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Sample records for berghei transmission revealed

  1. Critical role of a K+ channel in Plasmodium berghei transmission revealed by targeted gene disruption

    DEFF Research Database (Denmark)

    Ellekvist, Peter; Maciel, Jorge; Mlambo, Godfree;

    2008-01-01

    through the mosquito vector remains unknown. We hypothesize that these two K(+) channels mediate the transport of K(+) in the parasites, and thus are important for parasite survival. To test this hypothesis, we identified the orthologue of one of the P. falciparum K(+) channels, PfKch1, in the rodent...... inhibition of the development of PbKch1-null parasites in Anopheles stephensi mosquitoes. In conclusion, these studies demonstrate that PbKch1 contributes to the transport of K(+) in P. berghei parasites and supports the growth of the parasites, in particular the development of oocysts in the mosquito midgut...

  2. Bone marrow chimeric mice reveal a dual role for CD36 in Plasmodium berghei ANKA infection

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    Febbraio Maria

    2007-03-01

    Full Text Available Abstract Background Adhesion of Plasmodium-infected red blood cells (iRBC to different host cells, ranging from endothelial to red blood cells, is associated to malaria pathology. In vitro studies have shown the relevance of CD36 for adhesion phenotypes of Plasmodium falciparum iRBC such as sequestration, platelet mediated clumping and non-opsonic uptake of iRBC. Different adhesion phenotypes involve different host cells and are associated with different pathological outcomes of disease. Studies with different human populations with CD36 polymorphisms failed to attribute a clear role to CD36 expression in human malaria. Up to the present, no in vivo model has been available to study the relevance of different CD36 adhesion phenotypes to the pathological course of Plasmodium infection. Methods Using CD36-deficient mice and their control littermates, CD36 bone marrow chimeric mice, expressing CD36 exclusively in haematopoietic cells or in non-haematopoietic cells, were generated. Irradiated CD36-/- and wild type mice were also reconstituted with syngeneic cells to control for the effects of irradiation. The reconstituted mice were infected with Plasmodium berghei ANKA and analysed for the development of blood parasitaemia and neurological symptoms. Results All mice reconstituted with syngeneic bone marrow cells as well as chimeric mice expressing CD36 exclusively in non-haematopoietic cells died from experimental cerebral malaria between day 6 and 12 after infection. A significant proportion of chimeric mice expressing CD36 only in haematopoietic cells did not die from cerebral malaria. Conclusion The analysis of bone marrow chimeric mice reveals a dual role of CD36 in P. berghei ANKA infection. Expression of CD36 in haematopoietic cells, most likely macrophages and dendritic cells, has a beneficial effect that is masked in normal mice by adverse effects of CD36 expression in non-haematopoietic cells, most likely endothelial cells.

  3. Attempted isolation of the gene encoding the 21 Kd Plasmodium berghei ookinete transmission blocking antigen from Plasmodium yoelli and Plasmodium vivax

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    G. C. Barker

    1994-01-01

    Full Text Available The 21kD ookinete antigen of Plasmodium berghei (Pbs 21 has been shown to elicit an effective and long lasting transmission blocking immune response in mice. Having cloned and sequenced this antigen (Paton et al. 1993 the sequence was compared to the genes of the same family previously identified in P. falciparum, P. gallinaceum (Kaslow et al. 1989 and P. reichenowi (Lal et al. 1990. Four conserved areas were identified in this comparison, to which degenerate oligonucleotides were designed. PCR amplification and screening of genomic libraries was then carried out using these oligonucleotides. The P. yoelii gene was successfully cloned and a number of novel P. vivax genes identified but the P. vivax homologue of Pbs21 remains elusive.

  4. Apoptosis of erythrocytic stage parasites of Plasmodium berghei chloroquine-resistant strain

    Institute of Scientific and Technical Information of China (English)

    CHEN Ke-qiang; SONG Guan-hong

    2002-01-01

    Objective: To explore the characteristics of crisis state at erythrocytic stage of Plasmodium berghei chloroquine-resistant (RC) strain. Methods: Agarose electrophoresis, optical and transmission electron microscopes were used. Patterns of genomic DNA structures and ultra-structures of the erythrocytic parasites were observed in ICA mice (infected with the RC strain) during rising and declining of parasitemia. Results: During the declining parasitemia, the erythrocytic stage parasites of the RC strain showed round or oval appearance with intact plasma membrane and shrank nuclei with no metabolic window, mitochondria or other membranaceous structures. Their DNA electrophoretogram revealed a ladder pattern which evidently differed from the parasites of the RC strain in the rising parasitemia and the chloroquine-sensitive (N) strain.Conclusion: The crisis state of the erythrocytic stage parasites of the P. berghei chloroquine-resistant (RC)strain is characterized by apoptosis.

  5. Serial Analysis of Gene Expression in Plasmodium berghei salivary gland sporozoites

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    Ménard Robert

    2007-12-01

    Full Text Available Abstract Background The invasion of Anopheles salivary glands by Plasmodium sporozoites is an essential step for transmission of the parasite to the vertebrate host. Salivary gland sporozoites undergo a developmental programme to express genes required for their journey from the site of the mosquito bite to the liver and subsequent invasion of, and development within, hepatocytes. A Serial Analysis of Gene Expression was performed on Anopheles gambiae salivary glands infected or not with Plasmodium berghei and we report here the analysis of the Plasmodium sporozoite transcriptome. Results Annotation of 530 tag sequences homologous to Plasmodium berghei genomic sequences identified 123 genes expressed in salivary gland sporozoites and these genes were classified according to their transcript abundance. A subset of these genes was further studied by quantitative PCR to determine their expression profiles. This revealed that sporozoites modulate their RNA amounts not only between the midgut and salivary glands, but also during their storage within the latter. Among the 123 genes, the expression of 66 is described for the first time in sporozoites of rodent Plasmodium species. Conclusion These novel sporozoite expressed genes, especially those expressed at high levels in salivary gland sporozoites, are likely to play a role in Plasmodium infectivity in the mammalian host.

  6. Characterization of Plasmodium developmental transcriptomes in Anopheles gambiae midgut reveals novel regulators of malaria transmission.

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    Akinosoglou, Karolina A; Bushell, Ellen S C; Ukegbu, Chiamaka Valerie; Schlegelmilch, Timm; Cho, Jee-Sun; Redmond, Seth; Sala, Katarzyna; Christophides, George K; Vlachou, Dina

    2015-02-01

    The passage through the mosquito is a major bottleneck for malaria parasite populations and a target of interventions aiming to block disease transmission. Here, we used DNA microarrays to profile the developmental transcriptomes of the rodent malaria parasite Plasmodium berghei in vivo, in the midgut of Anopheles gambiae mosquitoes, from parasite stages in the midgut blood bolus to sporulating oocysts on the basal gut wall. Data analysis identified several distinct transcriptional programmes encompassing genes putatively involved in developmental processes or in interactions with the mosquito. At least two of these programmes are associated with the ookinete development that is linked to mosquito midgut invasion and establishment of infection. Targeted disruption by homologous recombination of two of these genes resulted in mutant parasites exhibiting notable infection phenotypes. GAMER encodes a short polypeptide with granular localization in the gametocyte cytoplasm and shows a highly penetrant loss-of-function phenotype manifested as greatly reduced ookinete numbers, linked to impaired male gamete release. HADO encodes a putative magnesium phosphatase with distinctive cortical localization along the concave ookinete periphery. Disruption of HADO compromises ookinete development leading to significant reduction of oocyst numbers. Our data provide important insights into the molecular framework underpinning Plasmodium development in the mosquito and identifies two genes with important functions at initial stages of parasite development in the mosquito midgut.

  7. Antimalarial effect of agmatine on Plasmodium berghei K173 strain

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    SURui-Bin; WEIXiao-Li; LIUYin; LIJin

    2003-01-01

    AIM: To study the antimalarial effect of agmatine (Agm) on chloroquine-susceptible Plasmodium berghei K173strain (S strain) and the P berghei K173 resistant strain (R strain). METHODS: The antimalarial effects of Agm onP berghei K173 S strain and R strain were evaluated by Peters 4-d suppression test in mice. RESULTS: Agm(12.5-200 mg/kg,ig,daily) decreased the parasitemia for both P berghei K173 S strain (IC50=139 mg/kg) and Rstrain (IC50=126mg/kg) in mice. Subcutaneous injection (sc) of Agm (5-40mg/kg,tid) showed relatively strongerantimalarial effect than intragastric gavage (IC50=30 mg/kg) in P berghei K 173 S strain. Spermidine antagonized theantimalarial effect of Agm for P berghei K173 S strain and R strain. Agm did not reverse the chloroquine resistanceof P berghei K173 S strain, dl-α-Difluoromethylornithine (DFMO, sc) decreased the parasitemia of P BergheiK173 S strain and this effect was antagonized by spermidine. CONCLUSION: Agm has an antimalarial effect andthe mechanism is related to its inhibition of polyamine synthesis.

  8. Antimalarial activity of Malaysian Plectranthus amboinicus against Plasmodium berghei

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    Norazsida Ramli

    2014-01-01

    Full Text Available Context: Malaria is a mosquito-borne disease caused by parasitic protozoa from the genus of Plasmodium. The protozoans have developed resistance against many of current drugs. It is urgent to find an alternative source of new antimalarial agent. In the effort to discover new antimalarial agents, this research has been conducted on Plectranthus amboinicus. Aims: This study was conducted to evaluate the toxicity and antiplasmodial properties of P. amboinicus. Materials and Methods: Acute oral toxicity dose at 5000 mg/kg was conducted to evaluate the safety of this extract. Twenty mice were divided into control and experimental group. All the mice were observed for signs of toxicity, mortality, weight changes and histopathological changes. Antimalarial activity of different extract doses of 50, 200, 400 and 1000 mg/kg were tested in vivo against Plasmodium berghei infections in mice (five mice for each group during early, established and residual infections. Results: The acute oral toxicity test revealed that no mortality or evidence of adverse effects was seen in the treated mice. The extract significantly reduced the parasitemia by the 50 (P = 0.000, 200 (P = 0.000 and 400 mg/kg doses (P = 0.000 in the in vivo prophylactic assay. The percentage chemo-suppression was calculated as 83.33% for 50 mg/kg dose, 75.62% for 200 mg/kg dose and 90.74% for 400 mg/kg dose. Body weight of all treated groups; T1, T2, T3 and T4 also showed enhancement after 7 days posttreatment. Statistically no reduction of parasitemia calculated for curative and suppressive test. Conclusion: Thus, this extract may give a promising agent to be used as a prophylactic agent of P. berghei infection.

  9. Cytokine response to pregnancy-associated recrudescence of Plasmodium berghei infection in mice with pre-existing immunity to malaria

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    Megnekou, Rosette; Staalsoe, Trine; Hviid, Lars

    2013-01-01

    During childhood, residents of areas with stable transmission of Plasmodium falciparum parasites acquire substantial protective immunity to malaria, and adults therefore rarely experience clinical disease episodes. However, susceptibility to infection reappears in pregnant women, particularly...... primigravidae. This is due to appearance of antigenic parasite variants that are restricted to pregnancy. Variant-specific immunity also governs pregnancy-associated recrudescence of Plasmodium berghei infection in pregnant mice. Pregnancy-related changes in the plasma cytokine levels of mice with immunity...

  10. Salivary gland-specific P. berghei reporter lines enable rapid evaluation of tissue-specific sporozoite loads in mosquitoes.

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    Chandra Ramakrishnan

    Full Text Available Malaria is a life-threatening human infectious disease transmitted by mosquitoes. Levels of the salivary gland sporozoites (sgs, the only mosquito stage infectious to a mammalian host, represent an important cumulative index of Plasmodium development within a mosquito. However, current techniques of sgs quantification are laborious and imprecise. Here, transgenic P. berghei reporter lines that produce the green fluorescent protein fused to luciferase (GFP-LUC specifically in sgs were generated, verified and characterised. Fluorescence microscopy confirmed the sgs stage specificity of expression of the reporter gene. The luciferase activity of the reporter lines was then exploited to establish a simple and fast biochemical assay to evaluate sgs loads in whole mosquitoes. Using this assay we successfully identified differences in sgs loads in mosquitoes silenced for genes that display opposing effects on P. berghei ookinete/oocyst development. It offers a new powerful tool to study infectivity of P. berghei to the mosquito, including analysis of vector-parasite interactions and evaluation of transmission-blocking vaccines.

  11. Indigofera pulchra leaves extracts contain anti-Plasmodium berghei agents

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    Sani Ibrahim

    2011-06-01

    Full Text Available This study was conducted to investigate the anti-Plasmodium berghei activities of some extracts from Indigofera pulchra leaves. Six groups of mice were intraperitoneally infected with chloroquine sensitive P. berghei (NK 65 among which two groups were orally treated with 100 and 200 mg/kg body weight of methanol leaves extract while another two groups were treated with 100 and 200 mg/kg of n-butanol fraction derived from the methanol extract. Another infected group was treated with chloroquine (25 mg/kg whereas the remaining infected group was left untreated. All infected treated groups possessed a significantly (p<0.05 lowered number of parasitized erythrocytes than the infected untreated group throughout the experimental period except at day 6 post-infection. However, the 200 mg/kg n-butanol fraction treated group demonstrated a persistently lower number of parasitized erythrocytes than other extract-treated groups after day 9 post infection to the termination of the experiment. The P. berghei was found to induce anemia whose severity was significantly (p<0.05 ameliorated by all the treatments. It was concluded that the methanol extract and n-butanol fraction of I. pulchra contains anti-P. berghei phytochemicals that could ameliorate the parasite-induced anemia.

  12. Microstructure of atmospheric particles revealed by TXM and a new mode of influenza virus transmission

    Energy Technology Data Exchange (ETDEWEB)

    Bao, L.M., E-mail: baoliangman@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhang, G.L., E-mail: zhangguilin@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Lei, Q.T.; Li, Y.; Li, X.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Hwu, Y.K. [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Yi, J.M. [Advanced Photon Source, Argonne National Laboratory, Argonne 60439 (United States)

    2015-09-15

    For control of influenza, firstly it is important to find the real virus transmission media. Atmospheric aerosol particles are presumably one of the media. In this study, three typical atmospheric inhaled particles in Shanghai were studied by the synchrotron based transmission X-ray microscopes (TXM). Three dimensional microstructure of the particles reveals that there are many pores contained in, particularly the coal combustion fly particles which may be possible virus carrier. The particles can transport over long distance and cause long-range infections due to its light weight. We suggest a mode which is droplet combining with aerosol mode. By this mode the transmission of global and pandemic influenzas and infection between inland avian far from population and poultry or human living in cities along coast may be explained.

  13. Roles of the amino terminal region and repeat region of the Plasmodium berghei circumsporozoite protein in parasite infectivity.

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    Cassandra Aldrich

    Full Text Available The circumsporozoite protein (CSP plays a key role in malaria sporozoite infection of both mosquito salivary glands and the vertebrate host. The conserved Regions I and II have been well studied but little is known about the immunogenic central repeat region and the N-terminal region of the protein. Rodent malaria Plasmodium berghei parasites, in which the endogenous CS gene has been replaced with the avian Plasmodium gallinaceum CS (PgCS sequence, develop normally in the A. stephensi mosquito midgut but the sporozoites are not infectious. We therefore generated P. berghei transgenic parasites carrying the PgCS gene, in which the repeat region was replaced with the homologous region of P. berghei CS (PbCS. A further line, in which both the N-terminal region and repeat region were replaced with the homologous regions of PbCS, was also generated. Introduction of the PbCS repeat region alone, into the PgCS gene, did not rescue sporozoite species-specific infectivity. However, the introduction of both the PbCS repeat region and the N-terminal region into the PgCS gene completely rescued infectivity, in both the mosquito vector and the mammalian host. Immunofluorescence experiments and western blot analysis revealed correct localization and proteolytic processing of CSP in the chimeric parasites. The results demonstrate, in vivo, that the repeat region of P. berghei CSP, alone, is unable to mediate sporozoite infectivity in either the mosquito or the mammalian host, but suggest an important role for the N-terminal region in sporozoite host cell invasion.

  14. Illumination of parainfluenza virus infection and transmission in living animals reveals a tissue-specific dichotomy.

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    Crystal W Burke

    2011-07-01

    Full Text Available The parainfluenza viruses (PIVs are highly contagious respiratory paramyxoviruses and a leading cause of lower respiratory tract (LRT disease. Since no vaccines or antivirals exist, non-pharmaceutical interventions are the only means of control for these pathogens. Here we used bioluminescence imaging to visualize the spatial and temporal progression of murine PIV1 (Sendai virus infection in living mice after intranasal inoculation or exposure by contact. A non-attenuated luciferase reporter virus (rSeV-luc(M-F* that expressed high levels of luciferase yet was phenotypically similar to wild-type Sendai virus in vitro and in vivo was generated to allow visualization. After direct intranasal inoculation, we unexpectedly observed that the upper respiratory tract (URT and trachea supported robust infection under conditions that result in little infection or pathology in the lungs including a low inoculum of virus, an attenuated virus, and strains of mice genetically resistant to lung infection. The high permissivity of the URT and trachea to infection resulted in 100% transmission to naïve contact recipients, even after low-dose (70 PFU inoculation of genetically resistant BALB/c donor mice. The timing of transmission was consistent with the timing of high viral titers in the URT and trachea of donor animals but was independent of the levels of infection in the lungs of donors. The data therefore reveals a disconnect between transmissibility, which is associated with infection in the URT, and pathogenesis, which arises from infection in the lungs and the immune response. Natural infection after transmission was universally robust in the URT and trachea yet limited in the lungs, inducing protective immunity without weight loss even in genetically susceptible 129/SvJ mice. Overall, these results reveal a dichotomy between PIV infection in the URT and trachea versus the lungs and define a new model for studies of pathogenesis, development of live

  15. P. berghei telomerase subunit TERT is essential for parasite survival.

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    Religa, Agnieszka A; Ramesar, Jai; Janse, Chris J; Scherf, Artur; Waters, Andrew P

    2014-01-01

    Telomeres define the ends of chromosomes protecting eukaryotic cells from chromosome instability and eventual cell death. The complex regulation of telomeres involves various proteins including telomerase, which is a specialized ribonucleoprotein responsible for telomere maintenance. Telomeres of chromosomes of malaria parasites are kept at a constant length during blood stage proliferation. The 7-bp telomere repeat sequence is universal across different Plasmodium species (GGGTTT/CA), though the average telomere length varies. The catalytic subunit of telomerase, telomerase reverse transcriptase (TERT), is present in all sequenced Plasmodium species and is approximately three times larger than other eukaryotic TERTs. The Plasmodium RNA component of TERT has recently been identified in silico. A strategy to delete the gene encoding TERT via double cross-over (DXO) homologous recombination was undertaken to study the telomerase function in P. berghei. Expression of both TERT and the RNA component (TR) in P. berghei blood stages was analysed by Western blotting and Northern analysis. Average telomere length was measured in several Plasmodium species using Telomere Restriction Fragment (TRF) analysis. TERT and TR were detected in blood stages and an average telomere length of ∼ 950 bp established. Deletion of the tert gene was performed using standard transfection methodologies and we show the presence of tert- mutants in the transfected parasite populations. Cloning of tert- mutants has been attempted multiple times without success. Thorough analysis of the transfected parasite populations and the parasite obtained from extensive parasite cloning from these populations provide evidence for a so called delayed death phenotype as observed in different organisms lacking TERT. The findings indicate that TERT is essential for P. berghei cell survival. The study extends our current knowledge on telomere biology in malaria parasites and validates further investigations to

  16. P. berghei telomerase subunit TERT is essential for parasite survival.

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    Agnieszka A Religa

    Full Text Available Telomeres define the ends of chromosomes protecting eukaryotic cells from chromosome instability and eventual cell death. The complex regulation of telomeres involves various proteins including telomerase, which is a specialized ribonucleoprotein responsible for telomere maintenance. Telomeres of chromosomes of malaria parasites are kept at a constant length during blood stage proliferation. The 7-bp telomere repeat sequence is universal across different Plasmodium species (GGGTTT/CA, though the average telomere length varies. The catalytic subunit of telomerase, telomerase reverse transcriptase (TERT, is present in all sequenced Plasmodium species and is approximately three times larger than other eukaryotic TERTs. The Plasmodium RNA component of TERT has recently been identified in silico. A strategy to delete the gene encoding TERT via double cross-over (DXO homologous recombination was undertaken to study the telomerase function in P. berghei. Expression of both TERT and the RNA component (TR in P. berghei blood stages was analysed by Western blotting and Northern analysis. Average telomere length was measured in several Plasmodium species using Telomere Restriction Fragment (TRF analysis. TERT and TR were detected in blood stages and an average telomere length of ∼ 950 bp established. Deletion of the tert gene was performed using standard transfection methodologies and we show the presence of tert- mutants in the transfected parasite populations. Cloning of tert- mutants has been attempted multiple times without success. Thorough analysis of the transfected parasite populations and the parasite obtained from extensive parasite cloning from these populations provide evidence for a so called delayed death phenotype as observed in different organisms lacking TERT. The findings indicate that TERT is essential for P. berghei cell survival. The study extends our current knowledge on telomere biology in malaria parasites and validates further

  17. Network-based diffusion analysis reveals cultural transmission of lobtail feeding in humpback whales.

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    Allen, Jenny; Weinrich, Mason; Hoppitt, Will; Rendell, Luke

    2013-04-26

    We used network-based diffusion analysis to reveal the cultural spread of a naturally occurring foraging innovation, lobtail feeding, through a population of humpback whales (Megaptera novaeangliae) over a period of 27 years. Support for models with a social transmission component was 6 to 23 orders of magnitude greater than for models without. The spatial and temporal distribution of sand lance, a prey species, was also important in predicting the rate of acquisition. Our results, coupled with existing knowledge about song traditions, show that this species can maintain multiple independently evolving traditions in its populations. These insights strengthen the case that cetaceans represent a peak in the evolution of nonhuman culture, independent of the primate lineage.

  18. Antimalarial efficacy of Albizia lebbeck (Leguminosae against Plasmodium falciparum in vitro & P. berghei in vivo

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    Shagun Kalia

    2015-01-01

    Full Text Available Background & objectives: Albizia lebbeck Benth. (Leguminosae has long been used in Indian traditional medicine. The current study was designed to test antimalarial activity of ethanolic bark extract of A. lebbeck (EBEAL. Methods: EBEAL was prepared by soxhlet extraction and subjected to phytochemical analysis. The extract was evaluated for its in vitro antimalarial activity against Plasmodium falciparum chloroquine (CQ sensitive (MRC2 and CQ resistant (RKL9 strains. Cytotoxicity (CC 50 of extract against HeLa cells was evaluated. Median lethal dose (LD 50 was determined to assess safety of EBEAL in BALB/c mice. Schizonticidal (100-1000 mg/kg and preventive (100-750 mg/kg activities of EBEAL were evaluated against P. berghei. Curative activity (100-750 mg/kg of extract was also evaluated. Results: Phytochemical screening revealed presence of alkaloids, flavonoids, phenols, saponins, terpenes and phytosterols. The extract exhibited IC 50 of 8.2 µg/ml (MRC2 and 5.1 µg/ml (RKL9. CC 50 of extract on HeLa cell line was calculated to be >1000 µg/ml. EBEAL showed selectivity indices (SI of >121.9 and >196.07 against MRC2 and RKL9 strains of P. falciparum, respectively. LD 50 of EBEAL was observed to be >5 g/kg. Dose-dependent chemosuppression was observed with significant ( p100 mg/kg. Significant (P<0.001 curative and repository activities were exhibited by 750 mg/kg concentration of extract on D7. Interpretation & conclusions: The present investigation reports antiplasmodial efficacy of EBEAL in vitro against P. falciparum as evident by high SI values. ED 50 of <100 mg/kg against P. berghei categorizes EBEAL as active antimalarial. Further studies need to be done to exploit its antiplasmodial activity further.

  19. The ETRAMP family member SEP2 is expressed throughout Plasmodium berghei life cycle and is released during sporozoite gliding motility.

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    Chiara Currà

    Full Text Available The early transcribed membrane proteins ETRAMPs belong to a family of small, transmembrane molecules unique to Plasmodium parasite, which share a signal peptide followed by a short lysine-rich stretch, a transmembrane domain and a variable, highly charged C-terminal region. ETRAMPs are usually expressed in a stage-specific manner. In the blood stages they localize to the parasitophorous vacuole membrane and, in described cases, to vesicle-like structures exported to the host erythrocyte cytosol. Two family members of the rodent parasite Plasmodium berghei, uis3 and uis4, localize to secretory organelles of sporozoites and to the parasitophorous membrane vacuole of the liver stages. By the use of specific antibodies and the generation of transgenic lines, we showed that the P. berghei ETRAMP family member SEP2 is abundantly expressed in gametocytes as well as in mosquito and liver stages. In intracellular parasite stages, SEP2 is routed to the parasitophorous vacuole membrane while, in invasive ookinete and sporozoite stages, it localizes to the parasite surface. To date SEP2 is the only ETRAMP protein detected throughout the parasite life cycle. Furthermore, SEP2 is also released during gliding motility of salivary gland sporozoites. A limited number of proteins are known to be involved in this key function and the best characterized, the CSP and TRAP, are both promising transmission-blocking candidates. Our results suggest that ETRAMP members may be viewed as new potential candidates for malaria control.

  20. Identification and bioinformatic characterization of a multidrug resistance associated protein (ABCC) gene in Plasmodium berghei

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    González-Pons, María; Szeto, Ada C; González-Méndez, Ricardo; Serrano, Adelfa E

    2009-01-01

    Background The ATP-binding cassette (ABC) superfamily is one of the largest evolutionarily conserved families of proteins. ABC proteins play key roles in cellular detoxification of endobiotics and xenobiotics. Overexpression of certain ABC proteins, among them the multidrug resistance associated protein (MRP), contributes to drug resistance in organisms ranging from human neoplastic cells to parasitic protozoa. In the present study, the Plasmodium berghei mrp gene (pbmrp) was partially characterized and the predicted protein was classified using bioinformatics in order to explore its putative involvement in drug resistance. Methods The pbmrp gene from the P. berghei drug sensitive, N clone, was sequenced using a PCR strategy. Classification and domain organization of pbMRP were determined with bioinformatics. The Plasmodium spp. MRPs were aligned and analysed to study their conserved motifs and organization. Gene copy number and organization were determined via Southern blot analysis in both N clone and the chloroquine selected line, RC. Chromosomal Southern blots and RNase protection assays were employed to determine the chromosomal location and expression levels of pbmrp in blood stages. Results The pbmrp gene is a single copy, intronless gene with a predicted open reading frame spanning 5820 nucleotides. Bioinformatic analyses show that this protein has distinctive features characteristic of the ABCC sub-family. Multiple sequence alignments reveal a high degree of conservation in the nucleotide binding and transmembrane domains within the MRPs from the Plasmodium spp. analysed. Expression of pbmrp was detected in asexual blood stages. Gene organization, copy number and mRNA expression was similar in both lines studied. A chromosomal translocation was observed in the chloroquine selected RC line, from chromosome 13/14 to chromosome 8, when compared to the drug sensitive N clone. Conclusion In this study, the pbmrp gene was sequenced and classified as a member of

  1. Illumination of murine gammaherpesvirus-68 cycle reveals a sexual transmission route from females to males in laboratory mice.

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    Sylvie François

    Full Text Available Transmission is a matter of life or death for pathogen lineages and can therefore be considered as the main motor of their evolution. Gammaherpesviruses are archetypal pathogenic persistent viruses which have evolved to be transmitted in presence of specific immune response. Identifying their mode of transmission and their mechanisms of immune evasion is therefore essential to develop prophylactic and therapeutic strategies against these infections. As the known human gammaherpesviruses, Epstein-Barr virus and Kaposi's Sarcoma-associated Herpesvirus are host-specific and lack a convenient in vivo infection model; related animal gammaherpesviruses, such as murine gammaherpesvirus-68 (MHV-68, are commonly used as general models of gammaherpesvirus infections in vivo. To date, it has however never been possible to monitor viral excretion or virus transmission of MHV-68 in laboratory mice population. In this study, we have used MHV-68 associated with global luciferase imaging to investigate potential excretion sites of this virus in laboratory mice. This allowed us to identify a genital excretion site of MHV-68 following intranasal infection and latency establishment in female mice. This excretion occurred at the external border of the vagina and was dependent on the presence of estrogens. However, MHV-68 vaginal excretion was not associated with vertical transmission to the litter or with horizontal transmission to female mice. In contrast, we observed efficient virus transmission to naïve males after sexual contact. In vivo imaging allowed us to show that MHV-68 firstly replicated in penis epithelium and corpus cavernosum before spreading to draining lymph nodes and spleen. All together, those results revealed the first experimental transmission model for MHV-68 in laboratory mice. In the future, this model could help us to better understand the biology of gammaherpesviruses and could also allow the development of strategies that could prevent

  2. Plasmodium Berghei ANKA Infection in ICR Mice as a Model of Cerebral Malaria

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    F Othman

    2012-12-01

    Full Text Available Background: Animal models with various combination of host-parasite have long been employed to study malaria pathogenesis. Here, we describe the combination of Plasmodium berghei ANKA infec­tion in inbred ICR mice as a model of cerebral malaria (CM.Methods: Infection in mice was initiated by intraperitoneal injection of 2 x 107 (0.2ml parasitized red blood cells (PRBCs.Results: This model can produce a severe degree of infection presented by the high degree of parasitae­mia followed by death 6-7 days post infection. Severe anemia, splenomegaly, hepatomegaly and discolourations of major organs were observed. Histopathological findings revealed several impor­tant features mimicking human CM including, microvascular sequestration of PRBCs in major organs, particularly in the brain, hypertrophy and hyperplasia of the kupffer cells in the liver, pulmo­nary edema and hyaline membrane formation in the lungs and haemorrhages in the kidney’s medulla and cortex. Proinflammatory cytokines TNFα, IFNγ, IL-1, IL-6 and IL-18, and anti-inflammatory cytokine IL-10 were all found to be elevated in the plasma of infected mice.Conclusion: This model can reproduce many of the important features of CM and therefore can be used as a tool to advance our understanding of the disease pathogenesis.

  3. Protective immune mechanisms against pre-erythrocytic forms of Plasmodium berghei depend on the target antigen

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    Elke S. Bergmann-Leitner

    2014-01-01

    Full Text Available Pre-erythrocytic malaria vaccines are believed to either stop the injected sporozoites from reaching the liver or to direct cellular immune responses towards eliminating infected hepatocytes. The present study reveals for the first time the anatomical sites at which these immune mechanisms act against the malaria parasites. To determine the mechanisms leading to protection mediated by two previously characterized vaccines against either the circumsporozoite protein (CSP or the cell traversal protein for ookinetes and sporozoites (CelTOS, mice were immunized and subsequently challenged by subcutaneous injection of salivary gland sporozoites of luciferase-transgenic Plasmodium berghei parasites. The In Vivo Imaging System (IVIS was used to identify the anatomical site where the vaccine-induced immune response eliminates sporozoites after injection. The data demonstrate that CSP-based immunity acts at the site of infection (skin whereas CelTOS-based immunity is only partially efficient in the skin and allows reduced levels of liver infection that can be subsequently cleared. The results of this study challenge assumptions regarding CSP-mediated immune mechanisms and call into question the validity of some commonly used assays to evaluate anti-CSP immune responses. The knowledge of the mechanism and events leading to infection or immune defense will guide supportive treatment with drugs or combination therapies and thus accelerate the development of effective antimalarial strategies.

  4. The utility of Plasmodium berghei as a rodent model for anti-merozoite malaria vaccine assessment.

    Science.gov (United States)

    Goodman, Anna L; Forbes, Emily K; Williams, Andrew R; Douglas, Alexander D; de Cassan, Simone C; Bauza, Karolis; Biswas, Sumi; Dicks, Matthew D J; Llewellyn, David; Moore, Anne C; Janse, Chris J; Franke-Fayard, Blandine M; Gilbert, Sarah C; Hill, Adrian V S; Pleass, Richard J; Draper, Simon J

    2013-01-01

    Rodent malaria species Plasmodium yoelii and P. chabaudi have been widely used to validate vaccine approaches targeting blood-stage merozoite antigens. However, increasing data suggest the P. berghei rodent malaria may be able to circumvent vaccine-induced anti-merozoite responses. Here we confirm a failure to protect against P. berghei, despite successful antibody induction against leading merozoite antigens using protein-in-adjuvant or viral vectored vaccine delivery. No subunit vaccine approach showed efficacy in mice following immunization and challenge with the wild-type P. berghei strains ANKA or NK65, or against a chimeric parasite line encoding a merozoite antigen from P. falciparum. Protection was not improved in knockout mice lacking the inhibitory Fc receptor CD32b, nor against a Δsmac P. berghei parasite line with a non-sequestering phenotype. An improved understanding of the mechanisms responsible for protection, or failure of protection, against P. berghei merozoites could guide the development of an efficacious vaccine against P. falciparum.

  5. Transmissible [corrected] dog cancer genome reveals the origin and history of an ancient cell lineage.

    Science.gov (United States)

    Murchison, Elizabeth P; Wedge, David C; Alexandrov, Ludmil B; Fu, Beiyuan; Martincorena, Inigo; Ning, Zemin; Tubio, Jose M C; Werner, Emma I; Allen, Jan; De Nardi, Andrigo Barboza; Donelan, Edward M; Marino, Gabriele; Fassati, Ariberto; Campbell, Peter J; Yang, Fengtang; Burt, Austin; Weiss, Robin A; Stratton, Michael R

    2014-01-24

    Canine transmissible venereal tumor (CTVT) is the oldest known somatic cell lineage. It is a transmissible cancer that propagates naturally in dogs. We sequenced the genomes of two CTVT tumors and found that CTVT has acquired 1.9 million somatic substitution mutations and bears evidence of exposure to ultraviolet light. CTVT is remarkably stable and lacks subclonal heterogeneity despite thousands of rearrangements, copy-number changes, and retrotransposon insertions. More than 10,000 genes carry nonsynonymous variants, and 646 genes have been lost. CTVT first arose in a dog with low genomic heterozygosity that may have lived about 11,000 years ago. The cancer spawned by this individual dispersed across continents about 500 years ago. Our results provide a genetic identikit of an ancient dog and demonstrate the robustness of mammalian somatic cells to survive for millennia despite a massive mutation burden.

  6. Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock

    Science.gov (United States)

    Kamath, Pauline L.; Foster, Jeffrey T.; Drees, Kevin P.; Luikart, Gordon; Quance, Christine; Anderson, Neil J.; Clarke, P. Ryan; Cole, Eric K.; Drew, Mark L.; Edwards, William H.; Rhyan, Jack C.; Treanor, John J.; Wallen, Rick L.; White, Patrick J.; Robbe-Austerman, Suelee; Cross, Paul C.

    2016-01-01

    Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (B3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations.

  7. Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus)

    OpenAIRE

    Luncz, L.; Wittig, R.; Boesch, C.

    2015-01-01

    Recovering evidence of past human activities enables us to recreate behaviour where direct observations are missing. Here, we apply archaeological methods to further investigate cultural transmission processes in percussive tool use among neighbouring chimpanzee communities in the Taï National Park, Côte d'Ivoire, West Africa. Differences in the selection of nut-cracking tools between neighbouring groups are maintained over time, despite frequent female transfer, which leads to persistent cul...

  8. ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere

    Science.gov (United States)

    Rackham, Benjamin; Espinoza, Néstor; Apai, Dániel; López-Morales, Mercedes; Jordán, Andrés; Osip, David J.; Lewis, Nikole K.; Rodler, Florian; Fraine, Jonathan D.; Morley, Caroline V.; Fortney, Jonathan J.

    2017-01-01

    GJ 1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanet's atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum (4500–9260 Å) of GJ 1214b in 14 bins, measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of {R}p/{R}s=0.1146+/- 2× {10}-4 and mean uncertainty of σ ({R}p/{R}s)=8.7× {10}-4 in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission through the exoplanet's limb (the CPAT model), and use it to examine the cases of absorber and temperature heterogeneities in the stellar photosphere. We find the optical and near-infrared measurements are best explained by the combination of (1) photochemical haze in the exoplanetary atmosphere with a mode particle size r = 0.1 μm and haze-forming efficiency {f}{haze}=10 % and (2) faculae in the unocculted stellar disk with a temperature contrast {{Δ }}T={354}-46+46 K, assuming 3.2% surface coverage. The CPAT model can be used to assess potential contributions of heterogeneous stellar photospheres to observations of exoplanet transmission spectra, which will be important for searches for spectral features in the optical.

  9. ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere

    CERN Document Server

    Rackham, Benjamin; Apai, Dániel; López-Morales, Mercedes; Jordán, Andrés; Osip, David J; Lewis, Nikole K; Rodler, Florian; Fraine, Jonathan D; Morley, Caroline V; Fortney, Jonathan J

    2016-01-01

    GJ 1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanet's atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum ($4,500-9,260$\\AA) of GJ 1214b in 14 bins measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of ${R_{p}/R_{s} = 0.1146\\pm{2\\times10^{-4}}}$ and mean uncertainty of $\\sigma(R_{p}/R_{s})=8.7\\times10^{-4}$ in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission (CPAT) through the exoplanet's limb, and use it to exa...

  10. Molecular characterization of HCV in a Swedish county over 8 years (2002–2009 reveals distinct transmission patterns

    Directory of Open Access Journals (Sweden)

    Josefine Ederth

    2016-02-01

    Full Text Available Background: Hepatitis C virus (HCV is a major public health concern and data on its molecular epidemiology in Sweden is scarce. We carried out an 8-year population-based study of newly diagnosed HCV cases in one of Sweden's centrally situated counties, Södermanland (D-county. The aim was to characterize the HCV strains circulating, analyze their genetic relatedness to detect networks, and in combination with demographic data learn more about transmission. Methods: Molecular analyses of serum samples from 91% (N=557 of all newly notified cases in D-county, 2002–2009, were performed. Phylogenetic analysis (NS5B gene, 300 bp was linked to demographic data from the national surveillance database, SmiNet, to characterize D-county transmission clusters. The linear-by-linear association test (LBL was used to analyze trends over time. Results: The most prevalent subtypes were 1a (38% and 3a (34%. Subtype 1a was most prevalent among cases transmitted via sexual contact, via contaminated blood, or blood products, while subtype 3a was most prevalent among people who inject drugs (PWIDs. Phylogenetic analysis revealed that the subtype 3a sequences formed more and larger transmission clusters (50% of the sequences clustered, while the 1a sequences formed smaller clusters (19% of the sequences clustered, possibly suggesting different epidemics. Conclusion: We found different transmission patterns in D-county which may, from a public health perspective, have implications for how to control virus infections by targeted interventions.

  11. Naturally occurring triggers that induce apoptosis-like programmed cell death in Plasmodium berghei ookinetes.

    Directory of Open Access Journals (Sweden)

    Medhat Ali

    Full Text Available Several protozoan parasites have been shown to undergo a form of programmed cell death that exhibits morphological features associated with metazoan apoptosis. These include the rodent malaria parasite, Plasmodium berghei. Malaria zygotes develop in the mosquito midgut lumen, forming motile ookinetes. Up to 50% of these exhibit phenotypic markers of apoptosis; as do those grown in culture. We hypothesised that naturally occurring signals induce many ookinetes to undergo apoptosis before midgut traversal. To determine whether nitric oxide and reactive oxygen species act as such triggers, ookinetes were cultured with donors of these molecules. Exposure to the nitric oxide donor SNP induced a significant increase in ookinetes with condensed nuclear chromatin, activated caspase-like molecules and translocation of phosphatidylserine that was dose and time related. Results from an assay that detects the potential-dependent accumulation of aggregates of JC-1 in mitochondria suggested that nitric oxide does not operate via loss of mitochondrial membrane potential. L-DOPA (reactive oxygen species donor also caused apoptosis in a dose and time dependent manner. Removal of white blood cells significantly decreased ookinetes exhibiting a marker of apoptosis in vitro. Inhibition of the activity of nitric oxide synthase in the mosquito midgut epithelium using L-NAME significantly decreased the proportion of apoptotic ookinetes and increased the number of oocysts that developed. Introduction of a nitric oxide donor into the blood meal had no effect on mosquito longevity but did reduce prevalence and intensity of infection. Thus, nitric oxide and reactive oxygen species are triggers of apoptosis in Plasmodium ookinetes. They occur naturally in the mosquito midgut lumen, sourced from infected blood and mosquito tissue. Up regulation of mosquito nitric oxide synthase activity has potential as a transmission blocking strategy.

  12. Dark-field transmission electron microscopy of cortical bone reveals details of extrafibrillar crystals.

    Science.gov (United States)

    Schwarcz, Henry P; McNally, Elizabeth A; Botton, Gianluigi A

    2014-12-01

    In a previous study we showed that most of the mineral in bone is present in the form of "mineral structures", 5-6nm-thick, elongated plates which surround and are oriented parallel to collagen fibrils. Using dark-field transmission electron microscopy, we viewed mineral structures in ion-milled sections of cortical human bone cut parallel to the collagen fibrils. Within the mineral structures we observe single crystals of apatite averaging 5.8±2.7nm in width and 28±19nm in length, their long axes oriented parallel to the fibril axis. Some appear to be composite, co-aligned crystals as thin as 2nm. From their similarity to TEM images of crystals liberated from deproteinated bone we infer that we are viewing sections through platy crystals of apatite that are assembled together to form the mineral structures.

  13. Human sporotrichosis beyond the epidemic front reveals classical transmission types in Espírito Santo, Brazil.

    Science.gov (United States)

    de Araujo, Mariceli L; Rodrigues, Anderson M; Fernandes, Geisa F; de Camargo, Zoilo P; de Hoog, G Sybren

    2015-08-01

    Sporotrichosis has emerged as the main subcutaneous mycosis of humans and animals around the world. With particular differences in frequency, the major species includes Sporothrix brasiliensis, S. schenckii, S. globosa and S. luriei. In Brazil, the main aspect of this epidemic is based on the zoonotic transmission through the scratches and bites of diseased cats contaminated with S. brasiliensis. Areas free of feline sporotrichosis are poorly characterised in Brazil. We investigated by molecular tools the epidemiology of human sporotrichosis in the Espírito Santo (ES) state, an area adjacent to Rio de Janeiro where is the epicentre of the long-lasting outbreak of cat-transmitted sporotrichosis. The human cases in the ES state reveal the prevalence of classical transmission types where subjects are mainly infected by accidental traumatic inoculation during manipulation of contaminated plant material. In agreement with an environmental source, Sporothrix schenckii was the major aetiological agent in the classical transmission. Unlike Rio de Janeiro, this study shows that cat-transmitted epidemic in Espírito Santo is still scanty, although the geographic proximity and similar climatic features. Sporothrix brasiliensis was the agent in the feline-transmitted cases. Sporothrix globosa was isolated from a patient with fixed cutaneous lesions that did not report any contact with diseased animals. In conclusion, beyond the borders of Rio de Janeiro epidemic, agents of sporotrichosis in Espírito Santo show a scattered occurrence with high species diversity.

  14. Transmission electron microscopy of Tuberculina species (Helicobasidiales) reveals an unique mode of conidiogenesis within Basidiomycota.

    Science.gov (United States)

    Aghayeva, Dilzara N; Lutz, Matthias; Piątek, Marcin

    2016-08-01

    Tuberculina species represent the asexual life stage of the plant-parasitic sexual genus Helicobasidium. Tuberculina species are distributed all over the world, living in antagonistic symbiosis with over 150 rust species from at least 15 genera. Within the Basidiomycota, besides the spermogonia of rust fungi, only Tuberculina species develop distinct fructifications in the haplophase. However, the knowledge of conidiogenesis in Tuberculina is meagre. Therefore, conidial development in Tuberculina maxima, Tuberculina persicina, and Tuberculina sbrozzii was studied using transmission electron microscopy, and compared to each other as well as to spermatia formation in rust fungi. Significant ultrastructural characteristics such as the movement of nuclei in the process of conidium formation, and formation of the initial and late stages of conidiogenesis are documented. The mode of conidiogenesis of Tuberculina species is unique within the Basidiomycota in that (1) it is realized by haploid fructifications, (2) it is holoblastic, without annellidic proliferation, (3) the nucleus of the conidiogenous cell moves towards the forming conidium, divides, and no daughter nucleus remains inside the conidiogenous cell, and (4) the conidiogenous cell retains only cytoplasmic residues after the development of a single conidium, and a successive conidium is not produced.

  15. Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus).

    Science.gov (United States)

    Luncz, Lydia V; Wittig, Roman M; Boesch, Christophe

    2015-11-19

    Recovering evidence of past human activities enables us to recreate behaviour where direct observations are missing. Here, we apply archaeological methods to further investigate cultural transmission processes in percussive tool use among neighbouring chimpanzee communities in the Taï National Park, Côte d'Ivoire, West Africa. Differences in the selection of nut-cracking tools between neighbouring groups are maintained over time, despite frequent female transfer, which leads to persistent cultural diversity between chimpanzee groups. Through the recovery of used tools in the suggested natal territory of immigrants, we have been able to reconstruct the tool material selection of females prior to migration. In combination with direct observations of tool selection of local residents and immigrants after migration, we uncovered temporal changes in tool selection for immigrating females. After controlling for ecological differences between territories of immigrants and residents our data suggest that immigrants abandoned their previous tool preference and adopted the pattern of their new community, despite previous personal proficiency of the same foraging task. Our study adds to the growing body of knowledge on the importance of conformist tendencies in animals.

  16. Simulation of postsynaptic glutamate receptors reveals critical features of glutamatergic transmission.

    Directory of Open Access Journals (Sweden)

    Renaud Greget

    Full Text Available Activation of several subtypes of glutamate receptors contributes to changes in postsynaptic calcium concentration at hippocampal synapses, resulting in various types of changes in synaptic strength. Thus, while activation of NMDA receptors has been shown to be critical for long-term potentiation (LTP and long term depression (LTD of synaptic transmission, activation of metabotropic glutamate receptors (mGluRs has been linked to either LTP or LTD. While it is generally admitted that dynamic changes in postsynaptic calcium concentration represent the critical elements to determine the direction and amplitude of the changes in synaptic strength, it has been difficult to quantitatively estimate the relative contribution of the different types of glutamate receptors to these changes under different experimental conditions. Here we present a detailed model of a postsynaptic glutamatergic synapse that incorporates ionotropic and mGluR type I receptors, and we use this model to determine the role of the different receptors to the dynamics of postsynaptic calcium with different patterns of presynaptic activation. Our modeling framework includes glutamate vesicular release and diffusion in the cleft and a glutamate transporter that modulates extracellular glutamate concentration. Our results indicate that the contribution of mGluRs to changes in postsynaptic calcium concentration is minimal under basal stimulation conditions and becomes apparent only at high frequency of stimulation. Furthermore, the location of mGluRs in the postsynaptic membrane is also a critical factor, as activation of distant receptors contributes significantly less to calcium dynamics than more centrally located ones. These results confirm the important role of glutamate transporters and of the localization of mGluRs in postsynaptic sites in their signaling properties, and further strengthen the notion that mGluR activation significantly contributes to postsynaptic calcium

  17. Influence of antimalarial treatment on acquisition of immunity in Plasmodium berghei NK65 malaria.

    Science.gov (United States)

    Long, Ton That Ai; Nakazawa, Shusuke; Huaman, Maria Cecilia; Kanbara, Hiroji

    2002-07-01

    Antimalarial treatments during primary Plasmodium berghei NK65 infection in BALB/c mice influenced the acquisition of protective immunity against reinfection. Among subcurative treatments, lower doses better enable mice to acquire protective immunity than do higher doses. Eradication of parasites from the start of infection did not promote protective immunity.

  18. Nauclea latifolia aqueous leaf extract eliminates hepatic and cerebral Plasmodium berghei parasite in experimental mice

    Institute of Scientific and Technical Information of China (English)

    Innocent Onyesom; Ejovi Osioma; Precious Chiamaka Okereke

    2015-01-01

    Objective:To assess the effects of hot water leaf extract of Nauclea latifolia (N. latifolia) on antioxidant status, lipid peroxidation values and parasite levels in hepatic and brain tissue of experimental mice (BALB/c) infected with Plasmodium berghei (P. berghei) malaria. Methods:Forty nine mice were divided into seven groups (n=7) and used for the study. Group A (control) were given 0.2 mL/kg phosphate buffer saline;Group B mice were infected with P. berghei and treated with phosphate buffer saline. Groups C and D mice were also infected but treated with 200 and 300 mg/kg body weight of leaf extract respectively. Groups E and F mice were not infected, but received 200 and 300 mg/kg of leaf extract respectively. Group G mice were infected and treated with chloroquine (5 mg/kg). Liver and brain tissues of mice were prepared for both biochemical assay and microscopic examination. Results:Results showed that P. berghei malaria infection induced oxidative stress in both liver and brain tissues as evidenced by the significant (P Conclusions:The bioactive phytochemical(s) in N. latifolia should be structured and the mechanism(s) of its antimalarial tendency should be further investigated.

  19. Acoustic pathways revealed: simulated sound transmission and reception in Cuvier's beaked whale (Ziphius cavirostris).

    Science.gov (United States)

    Cranford, Ted W; Krysl, Petr; Hildebrand, John A

    2008-03-01

    The finite element modeling (FEM) space reported here contains the head of a simulated whale based on CT data sets as well as physical measurements of sound-propagation characteristics of actual tissue samples. Simulated sound sources placed inside and outside of an adult male Cuvier's beaked whale (Ziphius cavirostris) reveal likely sound propagation pathways into and out of the head. Two separate virtual sound sources that were located at the left and right phonic lips produced beams that converged just outside the head. This result supports the notion that dual sound sources can interfere constructively to form a biologically useful and, in fact, excellent sonar beam in front of the animal. The most intriguing FEM results concern pathways by which sounds reach the ears. The simulations reveal a previously undescribed 'gular pathway' for sound reception in Ziphius. Propagated sound pressure waves enter the head from below and between the lower jaws, pass through an opening created by the absence of the medial bony wall of the posterior mandibles, and continue toward the bony ear complexes through the internal mandibular fat bodies. This new pathway has implications for understanding the evolution of underwater hearing in odontocetes. Our model also provides evidence for receive beam directionality, off-axis acoustic shadowing and a plausible mechanism for the long-standing orthodox sound reception pathway in odontocetes. The techniques developed for this study can be used to study acoustic perturbation in a wide variety of marine organisms.

  20. Phase Boundary Propagation in Li-Alloying Battery Electrodes Revealed by Liquid-Cell Transmission Electron Microscopy.

    Science.gov (United States)

    Leenheer, Andrew J; Jungjohann, Katherine L; Zavadil, Kevin R; Harris, Charles T

    2016-06-28

    Battery cycle life is directly influenced by the microstructural changes occurring in the electrodes during charge and discharge cycles. Here, we image in situ the nanoscale phase evolution in negative electrode materials for Li-ion batteries using a fully enclosed liquid cell in a transmission electron microscope (TEM) to reveal early degradation that is not evident in the charge-discharge curves. To compare the electrochemical phase transformation behavior between three model materials, thin films of amorphous Si, crystalline Al, and crystalline Au were lithiated and delithiated at controlled rates while immersed in a commercial liquid electrolyte. This method allowed for the direct observation of lithiation mechanisms in nanoscale negative electrodes, revealing that a simplistic model of a surface-to-interior lithiation front is insufficient. For the crystalline films, a lithiation front spread laterally from a few initial nucleation points, with continued grain nucleation along the growing interface. The intermediate lithiated phases were identified using electron diffraction, and high-resolution postmortem imaging revealed the details of the final microstructure. Our results show that electrochemically induced solid-solid phase transformations can lead to highly concentrated stresses at the laterally propagating phase boundary which should be considered for future designs of nanostructured electrodes for Li-ion batteries.

  1. Single nucleotide polymorphism typing of Mycobacterium ulcerans reveals focal transmission of buruli ulcer in a highly endemic region of Ghana.

    Directory of Open Access Journals (Sweden)

    Katharina Röltgen

    Full Text Available Buruli ulcer (BU is an emerging necrotizing disease of the skin and subcutaneous tissue caused by Mycobacterium ulcerans. While proximity to stagnant or slow flowing water bodies is a risk factor for acquiring BU, the epidemiology and mode of M. ulcerans transmission is poorly understood. Here we have used high-throughput DNA sequencing and comparisons of the genomes of seven M. ulcerans isolates that appeared monomorphic by existing typing methods. We identified a limited number of single nucleotide polymorphisms (SNPs and developed a real-time PCR SNP typing method based on these differences. We then investigated clinical isolates of M. ulcerans on which we had detailed information concerning patient location and time of diagnosis. Within the Densu river basin of Ghana we observed dominance of one clonal complex and local clustering of some of the variants belonging to this complex. These results reveal focal transmission and demonstrate, that micro-epidemiological analyses by SNP typing has great potential to help us understand how M. ulcerans is transmitted.

  2. Efeito do Mycobacterium bovis BCG, lipopolissacarideo bacteriano e hidrocortisona no desenvolvimento de imunidade ao Plasmodium berghei em camundongos

    Directory of Open Access Journals (Sweden)

    José J. Ferraroni

    1986-02-01

    Full Text Available Mycobacterium bovis (BCG aumenta significantemente o desenvolvimento da imunidade nos camundongos CFW, C57BL/6, C57BL/l0ScN e BALB/c (Nu/+ para os estágios eritrocitos do Plasmodium berghei. Camundongos tratados com BCG requerem menos ciclos de infecção com P. berghei e cura pelo Fansidar (pirimetamina + sulfadoxina para desenvolverem imunidade sólida a este parasita do que os controles. Contudo, os animais que receberam BCG 30 dias antes do início da imunização evidenciaram uma perda precoce da imunidade adquirida para o P. berghei, quando comparado com os animais que receberam BCG 14 dias antes ou que não receberam BCG. Assim, sendo, o BCG aumentada a indução na resposta imune do hospedeiro ao P. berghei no curso de infecções subseqüentes. O tratamento de camundongos CFW, BALB/c e C57BL/6 com lipopolissacarídeo bacteriano ou hidrocortisona faz com que os animais requeiram um número maior de ciclos de infecção e cura para tornarem-se imunes ao P. berghei que os controles. O tratamento dos camundongos C57BL/10ScN com hidrocortisona aboliu completamente a sua habilidade de sobrevida subseqüentes a ciclos de infecção com P. berghei e cura pelo Fansidar.

  3. Molecular epidemiology of viral haemorrhagic septicaemia virus (VHSV) in British Columbia, Canada, reveals transmission from wild to farmed fish.

    Science.gov (United States)

    Garver, Kyle A; Traxler, Garth S; Hawley, Laura M; Richard, Jon; Ross, Jay P; Lovy, Jan

    2013-05-27

    Viral haemorrhagic septicaemia virus (VHSV) is a fish pathogen found throughout the Northern Hemisphere and is capable of infecting and causing mortality in numerous marine and freshwater hosts. In the coastal waters of British Columbia, Canada, the virus has been detected for 20 yr with many occurrences of mass mortalities among populations of Pacific herring Clupea pallasii (Valenciennes) and sardine Sardinops sagax as well as detections among cultured Atlantic Salmo salar and Chinook Oncorhynchus tshawytscha salmon. We compared nucleotide sequence of the full glycoprotein (G) gene coding region (1524 nt) of 63 VHSV isolates sampled during its recorded presence from 1993 to 2011 from 6 species and a total of 29 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVa within the major VHSV genetic group IV. Of the 63 virus isolates, there were 42 unique sequences, each of which was ephemeral, being repeatedly detected at most only 1 yr after its initial detection. Multiple sequence types were revealed during single viral outbreak events, and genetic heterogeneity was observed within isolates from individual fish. Moreover, phylogenetic analysis revealed a close genetic linkage between VHSV isolates obtained from pelagic finfish species and farmed salmonids, providing evidence for virus transmission from wild to farmed fish.

  4. Visualization of Malaria Parasites in the Skin Using the Luciferase Transgenic Parasite, Plasmodium berghei

    OpenAIRE

    Matsuoka, Hiroyuki; TOMITA, HIROYUKI; Hattori, Ryuta; Arai,Meiji; Hirai, Makoto

    2014-01-01

    We produced a transgenic rodent malaria parasite (Plasmodium berghei) that contained the luciferase gene under a promoter region of elongation factor-1α. These transgenic (TG) parasites expressed luciferase in all stages of their life cycle, as previously reported. However, we were the first to succeed in observing sporozoites as a mass in mouse skin following their deposition by the probing of infective mosquitoes. Our transgenic parasites may have emitted stronger bioluminescence than previ...

  5. Nauclea latifolia aqueous leaf extract eliminates hepatic and cerebral Plasmodium berghei parasite in experimental mice

    Institute of Scientific and Technical Information of China (English)

    Innocent; Onyesom; Ejovi; Osioma; Precious; Chiamaka; Okereke

    2015-01-01

    Objective: To assess the effects of hot water leaf extract of Nauclea latifolia(N. latifolia) on antioxidant status, lipid peroxidation values and parasite levels in hepatic and brain tissue of experimental mice(BALB/c) infected with Plasmodium berghei(P. berghei) malaria.Methods: Forty nine mice were divided into seven groups(n = 7) and used for the study. Group A(control) were given 0.2 m L/kg phosphate buffer saline; Group B mice were infected with P. berghei and treated with phosphate buffer saline. Groups C and D mice were also infected but treated with 200 and 300 mg/kg body weight of leaf extract respectively. Groups E and F mice were not infected, but received 200 and 300 mg/kg of leaf extract respectively. Group G mice were infected and treated with chloroquine(5 mg/kg). Liver and brain tissues of mice were prepared for both biochemical assay and microscopic examination. Results: Results showed that P. berghei malaria infection induced oxidative stress in both liver and brain tissues as evidenced by the significant(P < 0.05) decrease in antioxidants: superoxide dismutase, reduced glutathione and catalase. These reductions perhaps caused compromise in membrane integrity as indicated by the significant increase in lipid peroxidation product malondialdhyde. Malaria parasites were also identified in these tissues. However, N. latifolia treatment eliminated the parasites in tissues and protected them from oxidative damage even better than chloroquine treatment did, whose anti-malarial potency also cleared tissue parasites. The measurement of protection by N. latifolia against damage was strengthened by the insignificant micro structural alterations.Conclusions: The bioactive phytochemical(s) in N. latifolia should be structured and the mechanism(s) of its antimalarial tendency should be further investigated.

  6. Plasmodium berghei calcium dependent protein kinase 1 is not required for host cell invasion.

    Science.gov (United States)

    Jebiwott, Sylvia; Govindaswamy, Kavitha; Mbugua, Amos; Bhanot, Purnima

    2013-01-01

    Plasmodium Calcium Dependent Protein Kinase (CDPK1) is required for the development of sexual stages in the mosquito. In addition, it is proposed to play an essential role in the parasite's invasive stages possibly through the regulation of the actinomyosin motor and micronemal secretion. We demonstrate that Plasmodium berghei CDPK1 is dispensable in the parasite's erythrocytic and pre-erythrocytic stages. We successfully disrupted P. berghei CDPK1 (PbCDPK1) by homologous recombination. The recovery of erythrocytic stage parasites lacking PbCDPK1 (PbCDPK1-) demonstrated that PbCDPK1 is not essential for erythrocytic invasion or intra-erythrocytic development. To study PbCDPK1's role in sporozoites and liver stage parasites, we generated a conditional mutant (CDPK1 cKO). Phenotypic characterization of CDPK1 cKO sporozoites demonstrated that CDPK1 is redundant or dispensable for the invasion of mammalian hepatocytes, the egress of parasites from infected hepatocytes and through the subsequent erythrocytic cycle. We conclude that P. berghei CDPK1 plays an essential role only in the mosquito sexual stages.

  7. Plasmodium berghei calcium dependent protein kinase 1 is not required for host cell invasion.

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    Sylvia Jebiwott

    Full Text Available Plasmodium Calcium Dependent Protein Kinase (CDPK1 is required for the development of sexual stages in the mosquito. In addition, it is proposed to play an essential role in the parasite's invasive stages possibly through the regulation of the actinomyosin motor and micronemal secretion. We demonstrate that Plasmodium berghei CDPK1 is dispensable in the parasite's erythrocytic and pre-erythrocytic stages. We successfully disrupted P. berghei CDPK1 (PbCDPK1 by homologous recombination. The recovery of erythrocytic stage parasites lacking PbCDPK1 (PbCDPK1- demonstrated that PbCDPK1 is not essential for erythrocytic invasion or intra-erythrocytic development. To study PbCDPK1's role in sporozoites and liver stage parasites, we generated a conditional mutant (CDPK1 cKO. Phenotypic characterization of CDPK1 cKO sporozoites demonstrated that CDPK1 is redundant or dispensable for the invasion of mammalian hepatocytes, the egress of parasites from infected hepatocytes and through the subsequent erythrocytic cycle. We conclude that P. berghei CDPK1 plays an essential role only in the mosquito sexual stages.

  8. Phylogenetic analysis consistent with a clinical history of sexual transmission of HIV-1 from a single donor reveals transmission of highly distinct variants

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    McClure Myra

    2011-07-01

    Full Text Available Abstract Background To combat the pandemic of human immunodeficiency virus 1 (HIV-1, a successful vaccine will need to cope with the variability of transmissible viruses. Human hosts infected with HIV-1 potentially harbour many viral variants but very little is known about viruses that are likely to be transmitted, or even if there are viral characteristics that predict enhanced transmission in vivo. We show for the first time that genetic divergence consistent with a single transmission event in vivo can represent several years of pre-transmission evolution. Results We describe a highly unusual case consistent with a single donor transmitting highly related but distinct HIV-1 variants to two individuals on the same evening. We confirm that the clustering of viral genetic sequences, present within each recipient, is consistent with the history of a single donor across the viral env, gag and pol genes by maximum likelihood and Bayesian Markov Chain Monte Carlo based phylogenetic analyses. Based on an uncorrelated, lognormal relaxed clock of env gene evolution calibrated with other datasets, the time since the most recent common ancestor is estimated as 2.86 years prior to transmission (95% confidence interval 1.28 to 4.54 years. Conclusion Our results show that an effective design for a preventative vaccine will need to anticipate extensive HIV-1 diversity within an individual donor as well as diversity at the population level.

  9. Transmission electron microscopy and serial reconstructions reveal novel meiotic phenotypes for the ahp2 mutant of Arabidopsis thaliana.

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    Pathan, Nazia; Stronghill, Patti; Hasenkampf, Clare

    2013-03-01

    We have found novel phenotypes for the previously studied Arabidopsis thaliana (L.) Heynh. meiotic mutant ahp2. These phenotypes were revealed by analysis of reconstructions of normal and ahp2 nuclei that were imaged using transmission electron microscopy. Previous studies of the ahp2 mutant demonstrated that it has a general failure to form synaptonemal complexes, except for the nucleolus organizing regions, and it fails to complete reciprocal genetic exchange. Here, we show that even though the ahp2 chromosome axes have only 5% of the normal amount of synaptonemal complex formation, it nonetheless has slightly more than 40% of the axes involved in close alignment. We also observed two striking nuclear envelope associated abnormalities. Wild type nuclei contain two nucleoli, one nucleolus-like structure, and nuclear envelope associated structures that we refer to as nuclear envelope associated disks. The ahp2 nuclei have the two nucleoli, but they lack the third nucleolus-like structure and instead have a previously uncharacterized structure that spans the nuclear envelope. Additionally, ahp2 meiocytes have nuclear envelope associated disks that are narrower and more numerous (∼2×) than those seen in wild type, and unlike the wild type disks, they are in direct contact with the nuclear envelope.

  10. Effect of pre-existing Schistosoma haematobium infection on Plasmodium berghei multiplications in imprinting control region mice

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    Benjamin; Amoani; Elvis; Ofori; Ameyaw; Du-Bois; Asante; Francis; Ackah; Armah; James; Prah; Collins; Paa; Kwesi; Botchey; Johnson; Nyarko; Boampong

    2015-01-01

    Objective: To investigate the effect of pre-existing Schistosoma haematobium(S. haematobium) infection on malaria disease severity.Methods: The study involved the use of twenty-i ve imprinting control region mice, i fteen of which were initially infected with S. haematobium. Five of the remaining ten schistouninfected mice together with i ve schisto-infected mice were infected with Plasmodium berghei(P. berghei) after four weeks(acute stage) of schistosoma infection. The remaining i ve schisto-uninfected mice together with i ve schisto-infected mice were also infected with P. berghei after seven weeks(chronic stage) of schistosoma infection. The last i ve schistoinfected mice were used as control group. They were then monitored for changes in P. berghei parasitaemia on Days 3, 5, 7, 9 and 11 post-infection. Records on their survivability were also taken.Results: The co-infected mice had signii cantly higher malaria parasitaemia, compared with the mono-infected mice during acute S. haematobium infection. In contrast, the co-infected mice had signii cantly lower malaria parasitaemia during chronic S. haematobium infection and a higher survival rate.Conclusions: Co-infection of mice with P. berghei during acute S. haematobium infection resulted in rapid P. berghei development and increased malaria parasitaemia. However, the co-infection resulted in slower P. berghei development and decreased malaria parasitaemia with enhanced survivability of the mice during chronic S. haematobium infection. Therefore, pre-existing chronic S. haematobium infection may provide some protection to the host by reducing parasitaemia.

  11. New Insights Into the Transmissibility of Leishmania infantum From Dogs to Sand Flies: Experimental Vector-Transmission Reveals Persistent Parasite Depots at Bite Sites

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    Aslan, Hamide; Oliveira, Fabiano; Meneses, Claudio; Castrovinci, Philip; Gomes, Regis; Teixeira, Clarissa; Derenge, Candace A.; Orandle, Marlene; Gradoni, Luigi; Oliva, Gaetano; Fischer, Laurent; Valenzuela, Jesus G.; Kamhawi, Shaden

    2016-01-01

    Canine leishmaniasis (CanL) is a chronic fatal disease of dogs and a major source of human infection through propagation of parasites in vectors. Here, we infected 8 beagles through multiple experimental vector transmissions with Leishmania infantum–infected Lutzomyia longipalpis. CanL clinical signs varied, although live parasites were recovered from all dog spleens. Splenic parasite burdens correlated positively with Leishmania-specific interleukin 10 levels, negatively with Leishmania-specific interferon γ and interleukin 2 levels, and negatively with Leishmania skin test reactivity. A key finding was parasite persistence for 6 months in lesions observed at the bite sites in all dogs. These recrudesced following a second transmission performed at a distal site. Notably, sand flies efficiently acquired parasites after feeding on lesions at the primary bite site. In this study, controlled vector transmissions identify a potentially unappreciated role for skin at infectious bite sites in dogs with CanL, providing a new perspective regarding the mechanism of Leishmania transmissibility to vector sand flies. PMID:26768257

  12. The protective effect of Moringa oleifera leaf extract on liver damage in mice infected with Plasmodium berghei ANKA

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    Kittiyaporn Dondee

    2016-09-01

    Full Text Available Objective: To investigate the protective effect of Moringa oleifera leaf extract on liver damage in mice infected with Plasmodium berghei ANKA (P. berghei Methods: For extraction of Moringa oleifera (M. oleifera leaves, microwave with hot water method was used and acute toxicity study was then be done. Standard Peters’ test was carried out to test the efficacy of M. oleifera extract in vivo. The ICR mice were inoculated with 1 × 107 red blood cells infected with P. berghei strain by intraperitoneal injection. They were subsequently given with 100, 500 and 1000 mg/kg of this extract by intragastric route once a day for 4 consecutive days. Parasitemia was estimated using microscopy and levels of aspartate aminotransferase, alanine aminotransferase and albumin were also measured. Results: The M. oleifera leaf extract showed the protective activity on liver damage in mice infected with P. berghei in a dose-dependent fashion. It can be indicated by normal levels of aspartate aminotransferase, alanine aminotransferase and albumin in mice treated with extract. The 1000 mg/kg of extract was observed to present the highest activity. Interestingly, the dosedependent antimalarial activity was also found in the mice treated with extract. Conclusions: The M. oleifera leaf extract presented protective effect on liver damage in mice infected with P. berghei.

  13. The interplay between tubulins and P450 cytochromes during Plasmodium berghei invasion of Anopheles gambiae midgut.

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    Rute C Félix

    Full Text Available BACKGROUND: Plasmodium infection increases the oxidative stress inside the mosquito, leading to a significant alteration on transcription of Anopheles gambiae detoxification genes. Among these detoxification genes several P450 cytochromes and tubulins were differently expressed, suggesting their involvement in the mosquito's response to parasite invasion. P450 cytochromes are usually involved in the metabolism and detoxification of several compounds, but are also regulated by several pathogens, including malaria parasite. Tubulins are extremely important as components of the cytoskeleton, which rearrangement functions as a response to malaria parasite invasion. METHODOLOGY/PRINCIPAL FINDINGS: Gene silencing methods were used to uncover the effects of cytochrome P450 reductase, tubulinA and tubulinB silencing on the A. gambiae response to Plasmodium berghei invasion. The role of tubulins in counter infection processes was also investigated by inhibiting their effect. Colchicine, vinblastine and paclitaxel, three different tubulin inhibitors were injected into A. gambiae mosquitoes. Twenty-four hours post injection these mosquitoes were infected with P. berghei through a blood meal from infected CD1 mice. Cytochrome P450 gene expression was measured using RT-qPCR to detect differences in cytochrome expression between silenced, inhibited and control mosquitoes. Results showed that cytochrome P450 reductase silencing, as well as tubulin (A and B silencing and inhibition affected the efficiency of Plasmodium infection. Silencing and inhibition also affected the expression levels of cytochromes P450. CONCLUSIONS: Our results suggest the existence of a relationship between tubulins and P450 cytochromes during A. gambiae immune response to P. berghei invasion. One of the P450 cytochromes in this study, CYP6Z2, stands out as the potential link in this association. Further work is needed to fully understand the role of tubulin genes in the response to

  14. Proteomic and genetic analyses demonstrate that Plasmodium berghei blood stages export a large and diverse repertoire of proteins.

    Science.gov (United States)

    Pasini, Erica M; Braks, Joanna A; Fonager, Jannik; Klop, Onny; Aime, Elena; Spaccapelo, Roberta; Otto, Thomas D; Berriman, Matt; Hiss, Jan A; Thomas, Alan W; Mann, Matthias; Janse, Chris J; Kocken, Clemens H M; Franke-Fayard, Blandine

    2013-02-01

    Malaria parasites actively remodel the infected red blood cell (irbc) by exporting proteins into the host cell cytoplasm. The human parasite Plasmodium falciparum exports particularly large numbers of proteins, including proteins that establish a vesicular network allowing the trafficking of proteins onto the surface of irbcs that are responsible for tissue sequestration. Like P. falciparum, the rodent parasite P. berghei ANKA sequesters via irbc interactions with the host receptor CD36. We have applied proteomic, genomic, and reverse-genetic approaches to identify P. berghei proteins potentially involved in the transport of proteins to the irbc surface. A comparative proteomics analysis of P. berghei non-sequestering and sequestering parasites was used to determine changes in the irbc membrane associated with sequestration. Subsequent tagging experiments identified 13 proteins (Plasmodium export element (PEXEL)-positive as well as PEXEL-negative) that are exported into the irbc cytoplasm and have distinct localization patterns: a dispersed and/or patchy distribution, a punctate vesicle-like pattern in the cytoplasm, or a distinct location at the irbc membrane. Members of the PEXEL-negative BIR and PEXEL-positive Pb-fam-3 show a dispersed localization in the irbc cytoplasm, but not at the irbc surface. Two of the identified exported proteins are transported to the irbc membrane and were named erythrocyte membrane associated proteins. EMAP1 is a member of the PEXEL-negative Pb-fam-1 family, and EMAP2 is a PEXEL-positive protein encoded by a single copy gene; neither protein plays a direct role in sequestration. Our observations clearly indicate that P. berghei traffics a diverse range of proteins to different cellular locations via mechanisms that are analogous to those employed by P. falciparum. This information can be exploited to generate transgenic humanized rodent P. berghei parasites expressing chimeric P. berghei/P. falciparum proteins on the surface of

  15. Whole-Genome Sequencing of Measles Virus Genotypes H1 and D8 During Outbreaks of Infection Following the 2010 Olympic Winter Games Reveals Viral Transmission Routes.

    Science.gov (United States)

    Gardy, Jennifer L; Naus, Monika; Amlani, Ashraf; Chung, Walter; Kim, Hochan; Tan, Malcolm; Severini, Alberto; Krajden, Mel; Puddicombe, David; Sahni, Vanita; Hayden, Althea S; Gustafson, Reka; Henry, Bonnie; Tang, Patrick

    2015-11-15

    We used whole-genome sequencing to investigate a dual-genotype outbreak of measles occurring after the XXI Olympic Winter Games in Vancouver, Canada. By sequencing 27 complete genomes from H1 and D8 genotype measles viruses isolated from outbreak cases, we estimated the virus mutation rate, determined that person-to-person transmission is typically associated with 0 mutations between isolates, and established that a single introduction of H1 virus led to the expansion of the outbreak beyond Vancouver. This is the largest measles genomics project to date, revealing novel aspects of measles virus genetics and providing new insights into transmission of this reemerging viral pathogen.

  16. Inhibition of In Vivo Growth of Plasmodium berghei by Launaea taraxacifolia and Amaranthus viridis in Mice

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    Olorunnisola, Olubukola S.; Adegbola, Peter

    2016-01-01

    Launaea taraxacifolia and Amaranthus viridis used by people of Western Africa in the treatment of malaria and related symptoms were assessed for their antiplasmodial value against the chloroquine sensitive strain of Plasmodium berghei. Crude extracts (200 mg/kg) and chloroquine (5 mg/kg) were administered to different groups of Swiss mice. The percentage of parasitemia, survival time, and haematological parameters were determined. Both extracts significantly (p phytochemical investigations in the search for new and locally affordable antimalarial agents. PMID:28050307

  17. In vivo antimalarial activity of leaves of Plectranthus amboinicus (lour) spreng on Plasmodium berghei yoelii.

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    Periyanayagam, K; Nirmala Devi, K; Suseela, L; Uma, A; Ismail, M

    2008-06-01

    An invivo study of aqueous extract of the leaves of Plectranthus amboinicus on Plasmodium berghei yoelii was conducted on laboratory infected albino mice and compared with standard drug chloroquine. Reduction of parasitemia at 250 mg/kg and 500 mg/kg of aqueous extract for 24 hrs, 48 hrs, 72 hrs and 96 hrs were determined. The reduction of parasitemia after 96 hrs was 100%, 67.9% and 76.2% for standard, 250 mg/kg and 500 mg/kg of aqueous extract respectively. The isolation of active principle responsible for the reduction of parasitemia may give a promising drug molecule.

  18. Improved negative selection protocol for Plasmodium berghei in the rodent malarial model

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    Orr Rachael Y

    2012-03-01

    Full Text Available Abstract An improved methodology is presented here for transgenic Plasmodium berghei lines that express the negative selectable marker yFCU (a bifunctional protein that combines yeast cytosine deaminase and uridyl phosphoribosyl transferase (UPRT and substitutes delivery of selection drug 5-fluorocytosine (5FC by intraperitoneal injection for administration via the drinking water of the mice. The improved methodology is shown to be as effective, less labour-intensive, reduces animal handling and animal numbers required for successful selection thereby contributing to two of the "three Rs" of animal experimentation, namely refinement and reduction.

  19. Antiplasmodial activity of eco-friendly synthesized palladium nanoparticles using Eclipta prostrata extract against Plasmodium berghei in Swiss albino mice.

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    Rajakumar, Govindasamy; Rahuman, Abdul Abdul; Chung, Ill-Min; Kirthi, Arivarasan Vishnu; Marimuthu, Sampath; Anbarasan, Karunanithi

    2015-04-01

    Malaria is an infectious disease caused by the Plasmodium parasite that continues to be a health issue for humans. It is one of the most common pathogenic factors of morbidity and mortality. Palladium nanoparticles (Pd NPs) have been used as target antimicrobial compounds, as a catalyst to manufacture pharmaceuticals, degrade harmful environmental pollutants, and as sensors for the detection of various analyses. The aim of this study was to investigate the antiplasmodial activity of synthesized Pd NPs by using leaf aqueous extract of Eclipta prostrata against Plasmodium berghei in Swiss albino mice. The synthesized Pd NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscopy (SEM) with Energy dispersive X-ray spectroscopy (EDX), and High-resolution transmission electron microscope (HRTEM) with the Selected area (electron) diffraction (SAED). The XRD peaks appeared at 35.61°, 44.27°, 56.40°, and 74.51°, which correspond to (111), (200), (220), and (311) planes for palladium, respectively. The FTIR spectra that were carried out to identify the potential biomolecule of synthesized Pd NPs showed the peaks at 3361, 1540, 1399, 1257, 1049, and 659 in the region of 4000-500 cm(-1). The SEM images showed aggregation of NPs with an average size of 63 ± 1.4. The HRTEM images of the precipitated solid phase obtained after termination of the reaction of E. prostrata aqueous leaf extract were in the range from 18 to 64 nm with an average size of 27 ± 1.3 nm. The in vivo antiplasmodial assay was carried out as per Peters' 4-day suppressive test, and the synthesized Pd NP-treated mice group showed reduction of parasitemia by 78.13% with an inhibitory concentration (IC)50 value of 16.44 mg/kg/body weight. The growth inhibition of E. prostrata aqueous leaf extract, palladium acetate, and synthesized Pd NPs showed the IC20, IC50, and IC90 values of 1.90, 10.29, and 64.11; 4.49, 9.84, and 23.04; and 4.34, 8

  20. Study of the antimalarial properties of hydroxyethylamine derivatives using green fluorescent protein transformed Plasmodium berghei

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    Mariana Conceição Souza

    2015-06-01

    Full Text Available A rapid decrease in parasitaemia remains the major goal for new antimalarial drugs and thus, in vivo models must provide precise results concerning parasitaemia modulation. Hydroxyethylamine comprise an important group of alkanolamine compounds that exhibit pharmacological properties as proteases inhibitors that has already been proposed as a new class of antimalarial drugs. Herein, it was tested the antimalarial property of new nine different hydroxyethylamine derivatives using the green fluorescent protein (GFP-expressing Plasmodium berghei strain. By comparing flow cytometry and microscopic analysis to evaluate parasitaemia recrudescence, it was observed that flow cytometry was a more sensitive methodology. The nine hydroxyethylamine derivatives were obtained by inserting one of the following radical in the para position: H, 4Cl, 4-Br, 4-F, 4-CH3, 4-OCH3, 4-NO2, 4-NH2 and 3-Br. The antimalarial test showed that the compound that received the methyl group (4-CH3 inhibited 70% of parasite growth. Our results suggest that GFP-transfected P. berghei is a useful tool to study the recrudescence of novel antimalarial drugs through parasitaemia examination by flow cytometry. Furthermore, it was demonstrated that the insertion of a methyl group at the para position of the sulfonamide ring appears to be critical for the antimalarial activity of this class of compounds.

  1. Excess Fibrin Deposits Decrease Fetal Weight of Pregnant Mice Infected by Plasmodium berghei

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    Desy Andari

    2014-05-01

    Full Text Available Low birth weight is commonly attributed to malaria in pregnancy, but the cellular and molecular mechanisms that underlie this poor birth outcome are incompletely understood. A universally described histopathological feature of placental malaria is excessive deposition of fibrin, the end-product of the coagulation cascade. This study was conducted to compare fibrin deposit in pregnant mice that infected by Plasmodium berghei (treatment group to the normal pregnant mice (control group and its association with fetal weight. This research is in vivo experimental laboratory study that used 18 pregnant Balb/c mice which divided to the control the group (8 mice and treatment group (9 mice infected by P.berghei. Placentas were staining with Haematoxylin-Eosin (HE for fibrin deposits examination whereas fetal weight was performed with Mettler analytical balance AE 50. Fetal weight of the treatment group was lower than those of the control group (t test, p=0,002. Fibrin deposits were increased in the treatment group (t test, p=0,005 and influenced weight of fetuses (Spearman r= -0,586, p= 0,014. Weights of fetuses are interfered by fibrin deposits during malaria infection.

  2. Antihemolytic Activities of Green Tea, Safflower, and Mulberry Extracts during Plasmodium berghei Infection in Mice

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    Suthin Audomkasok

    2014-01-01

    Full Text Available Malaria-associated hemolysis is associated with mortality in adult patients. It has been speculated that oxidative stress and inflammation induced by malaria parasite are involved in its pathophysiology. Hence, we aimed to investigate the antihemolytic effect of green tea, safflower, and mulberry extracts against Plasmodium berghei infection. Aqueous crude extracts of these plants were prepared using hot water method and used for oral treatment in mice. Groups of ICR mice were infected with 6 × 106 infected red blood cells of P. berghei ANKA by intraperitoneal injection and given the extracts (500, 1500, and 3000 mg/kg twice a day for 4 consecutive days. To assess hemolysis, hematocrit levels were then evaluated. Malaria infection resulted in hemolysis. However, antihemolytic effects were observed in infected mice treated with these extracts at dose-dependent manners. In conclusion, aqueous crude extracts of green tea, safflower, and mulberry exerted antihemolysis induced by malaria infection. These plants may work as potential source in the development of variety of herbal formulations for malarial treatment.

  3. A cysteine protease inhibitor of plasmodium berghei is essential for exo-erythrocytic development.

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    Christine Lehmann

    2014-08-01

    Full Text Available Plasmodium parasites express a potent inhibitor of cysteine proteases (ICP throughout their life cycle. To analyze the role of ICP in different life cycle stages, we generated a stage-specific knockout of the Plasmodium berghei ICP (PbICP. Excision of the pbicb gene occurred in infective sporozoites and resulted in impaired sporozoite invasion of hepatocytes, despite residual PbICP protein being detectable in sporozoites. The vast majority of these parasites invading a cultured hepatocyte cell line did not develop to mature liver stages, but the few that successfully developed hepatic merozoites were able to initiate a blood stage infection in mice. These blood stage parasites, now completely lacking PbICP, exhibited an attenuated phenotype but were able to infect mosquitoes and develop to the oocyst stage. However, PbICP-negative sporozoites liberated from oocysts exhibited defective motility and invaded mosquito salivary glands in low numbers. They were also unable to invade hepatocytes, confirming that control of cysteine protease activity is of critical importance for sporozoites. Importantly, transfection of PbICP-knockout parasites with a pbicp-gfp construct fully reversed these defects. Taken together, in P. berghei this inhibitor of the ICP family is essential for sporozoite motility but also appears to play a role during parasite development in hepatocytes and erythrocytes.

  4. Antimalarial properties of Artemisia vulgaris L. ethanolic leaf extract in a Plasmodium berghei murine malaria model

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    Gayan S. Bamunuarachchi

    2013-12-01

    Full Text Available Background & objectives: Artemisinin isolated from Artemisia annua is the most potent antimalarial drug against chloroquine-resistant Plasmodium falciparum malaria. Artemisia vulgaris, an invasive weed, is the only Artemisia species available in Sri Lanka. A pilot study was undertaken to investigate the antiparasitic activity of an A. vulgaris ethanolic leaf extract (AVELE in a P. berghei ANKA murine malaria model that elicits pathogenesis similar to falciparum malaria. Methods: A 4-day suppressive and the curative assays determined the antiparasitic activity of AVELE using four doses (250, 500, 750 and 1000 mg/kg, Coartem® as the positive control and 5% ethanol as the negative control in male ICR mice infected with P. berghei. Results: The 500, 750 and 1000 mg/kg doses of AVELE significantly (p ≤0.01 inhibited parasitaemia by 79.3, 79.6 and 87.3% respectively, in the 4-day suppressive assay, but not in the curative assay. Chronic administration of the high dose of AVELE ruled out overt signs of toxicity and stress as well as hepatotoxicity, renotoxicity and haematotoxicity. Interpretation & conclusion: The oral administration of a crude ethonolic leaf extract of A. vulgaris is non-toxic and possesses potent antimalarial properties in terms of antiparasitic activity.

  5. Correlative scanning-transmission electron microscopy reveals that a chimeric flavivirus is released as individual particles in secretory vesicles.

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    Burlaud-Gaillard, Julien; Sellin, Caroline; Georgeault, Sonia; Uzbekov, Rustem; Lebos, Claude; Guillaume, Jean-Marc; Roingeard, Philippe

    2014-01-01

    The intracellular morphogenesis of flaviviruses has been well described, but flavivirus release from the host cell remains poorly documented. We took advantage of the optimized production of an attenuated chimeric yellow fever/dengue virus for vaccine purposes to study this phenomenon by microscopic approaches. Scanning electron microscopy (SEM) showed the release of numerous viral particles at the cell surface through a short-lived process. For transmission electron microscopy (TEM) studies of the intracellular ultrastructure of the small number of cells releasing viral particles at a given time, we developed a new correlative microscopy method: CSEMTEM (for correlative scanning electron microscopy - transmission electron microscopy). CSEMTEM analysis suggested that chimeric flavivirus particles were released as individual particles, in small exocytosis vesicles, via a regulated secretory pathway. Our morphological findings provide new insight into interactions between flaviviruses and cells and demonstrate that CSEMTEM is a useful new method, complementary to SEM observations of biological events by intracellular TEM investigations.

  6. Transmission of the Chromosome 1 R in Winter Wheat Germplasm Aimengniu and Its Derivatives Revealed by Molecular Markers

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chunhua; CUI Fa; ZONG Hao; WANG Yu-hai; BAO Yin-guang; HAO Yuan-feng; DU Bin; WANG Hong-gang

    2009-01-01

    In order to clarify the transmission of the rye chromosome 1R in winter wheat germplasm Aimengniu and its derivatives,17 derivatives and 7 types of Aimengniu were examined through molecular-marker technology.The results showed that the chromosome arm 1RS of Neuzucht was transmitted to 5 of the 7 types of Aimengniu,i.e.,Aimengniu II and Aimengniu Ⅳ-Aimengniu Ⅶ,no segment of 1RS was identified in Aimengniu Ⅰ or Aimengniu Ⅲ.As for the 17 derivatives,the 1RS chromosome arm of Aimengniu was transmitted to 11 derivatives,part segments of 1RS were found in 1 derivative,while no segment was found in the remaining 5 ones.The results provided the evidence that molecular-marker technology was an efficient approach and suitable for analysis of the transmission of chromosome 1R.

  7. Expression of cytosolic peroxiredoxins in Plasmodium berghei ookinetes is regulated by environmental factors in the mosquito bloodmeal.

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    Benjamin A Turturice

    2013-01-01

    Full Text Available The Plasmodium ookinete develops over several hours in the bloodmeal of its mosquito vector where it is exposed to exogenous stresses, including cytotoxic reactive oxygen species (ROS. How the parasite adapts to these challenging conditions is not well understood. We have systematically investigated the expression of three cytosolic antioxidant proteins, thioredoxin-1 (Trx-1, peroxiredoxin-1 (TPx-1, and 1-Cys peroxiredoxin (1-Cys Prx, in developing ookinetes of the rodent parasite Plasmodium berghei under various growth conditions. Transcriptional profiling showed that tpx-1 and 1-cys prx but not trx-1 are more strongly upregulated in ookinetes developing in the mosquito bloodmeal when compared to ookinetes growing under culture conditions. Confocal immunofluorescence imaging revealed comparable expression patterns on the corresponding proteins. 1-Cys Prx in particular exhibited strong expression in mosquito-derived ookinetes but was not detectable in cultured ookinetes. Furthermore, ookinetes growing in culture upregulated tpx-1 and 1-cys prx when challenged with exogenous ROS in a dose-dependent fashion. This suggests that environmental factors in the mosquito bloodmeal induce upregulation of cytosolic antioxidant proteins in Plasmodium ookinetes. We found that in a parasite line lacking TPx-1 (TPx-1KO, expression of 1-Cys Prx occurred significantly earlier in mosquito-derived TPx-1KO ookinetes when compared to wild type (WT ookinetes. The protein was also readily detectable in cultured TPx-1KO ookinetes, indicating that 1-Cys Prx at least in part compensates for the loss of TPx-1 in vivo. We hypothesize that this dynamic expression of the cytosolic peroxiredoxins reflects the capacity of the developing Plasmodium ookinete to rapidly adapt to the changing conditions in the mosquito bloodmeal. This would significantly increase its chances of survival, maturation and subsequent escape. Our results also emphasize that environmental conditions

  8. Proteomic profiling of Pseudomonas aeruginosa AES-1R, PAO1 and PA14 reveals potential virulence determinants associated with a transmissible cystic fibrosis-associated strain

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    Hare Nathan J

    2012-01-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is an opportunistic pathogen that is the major cause of morbidity and mortality in patients with cystic fibrosis (CF. While most CF patients are thought to acquire P. aeruginosa from the environment, person-person transmissible strains have been identified in CF clinics worldwide. The molecular basis for transmissibility and colonization of the CF lung remains poorly understood. Results A dual proteomics approach consisting of gel-based and gel-free comparisons were undertaken to analyse protein profiles in a transmissible, early (acute isolate of the Australian epidemic strain 1 (AES-1R, the virulent burns/wound isolate PA14, and the poorly virulent, laboratory-associated strain PAO1. Over 1700 P. aeruginosa proteins were confidently identified. AES-1R protein profiles revealed elevated abundance of proteins associated with virulence and siderophore biosynthesis and acquisition, antibiotic resistance and lipopolysaccharide and fatty acid biosynthesis. The most abundant protein in AES-1R was confirmed as a previously hypothetical protein with sequence similarity to carbohydrate-binding proteins and database search revealed this gene is only found in the CF-associated strain PA2192. The link with CF infection may suggest that transmissible strains have acquired an ability to rapidly interact with host mucosal glycoproteins. Conclusions Our data suggest that AES-1R expresses higher levels of proteins, such as those involved in antibiotic resistance, iron acquisition and virulence that may provide a competitive advantage during early infection in the CF lung. Identification of novel proteins associated with transmissibility and acute infection may aid in deciphering new strategies for intervention to limit P. aeruginosa infections in CF patients.

  9. Intra-epidemic evolutionary dynamics of a Dengue virus type 1 population reveal mutant spectra that correlate with disease transmission.

    Science.gov (United States)

    Hapuarachchi, Hapuarachchige Chanditha; Koo, Carmen; Kek, Relus; Xu, Helen; Lai, Yee Ling; Liu, Lilac; Kok, Suet Yheng; Shi, Yuan; Chuen, Raphael Lee Tze; Lee, Kim-Sung; Maurer-Stroh, Sebastian; Ng, Lee Ching

    2016-01-01

    Dengue virus (DENV) is currently the most prevalent mosquito-borne viral pathogen. DENVs naturally exist as highly heterogeneous populations. Even though the descriptions on DENV diversity are plentiful, only a few studies have narrated the dynamics of intra-epidemic virus diversity at a fine scale. Such accounts are important to decipher the reciprocal relationship between viral evolutionary dynamics and disease transmission that shape dengue epidemiology. In the current study, we present a micro-scale genetic analysis of a monophyletic lineage of DENV-1 genotype III (epidemic lineage) detected from November 2012 to May 2014. The lineage was involved in an unprecedented dengue epidemic in Singapore during 2013-2014. Our findings showed that the epidemic lineage was an ensemble of mutants (variants) originated from an initial mixed viral population. The composition of mutant spectrum was dynamic and positively correlated with case load. The close interaction between viral evolution and transmission intensity indicated that tracking genetic diversity through time is potentially a useful tool to infer DENV transmission dynamics and thereby, to assess the epidemic risk in a disease control perspective. Moreover, such information is salient to understand the viral basis of clinical outcome and immune response variations that is imperative to effective vaccine design.

  10. How Do People Become W.E.I.R.D.? Migration Reveals the Cultural Transmission Mechanisms Underlying Variation in Psychological Processes.

    Directory of Open Access Journals (Sweden)

    Alex Mesoudi

    Full Text Available Cultural psychologists have shown that people from Western, Educated, Industrialised, Rich, Democratic (WEIRD countries often exhibit different psychological processing to people from less-WEIRD countries. The former exhibit more individualistic and less collectivistic social orientation, and more analytic and less holistic cognition, than non-Westerners. Yet the mechanisms responsible for maintaining this cultural variation are unclear. Immigration is an ideal 'natural experiment' for uncovering such mechanisms. We used a battery of psychological measures previously shown to vary cross-culturally to compare the social orientation and cognitive style of 286 residents of East London from three cultural backgrounds: (i 1st-generation British Bangladeshi immigrants; (ii 2nd-generation British Bangladeshis raised in the UK to Bangladeshi-raised parents; and (iii non-migrants whose parents were born and raised in the UK. Model comparison revealed that individualism and dispositional attribution, typical of Western societies, are driven primarily by horizontal cultural transmission (e.g. via mass media, with parents and other family members having little or no effect, while collectivism, social closeness and situational attribution were driven by a mix of vertical/oblique cultural transmission (e.g. via family contact and horizontal cultural transmission. These individual-level transmission dynamics can explain hitherto puzzling population-level phenomena, such as the partial acculturation of 2nd-generation immigrants on measures such as collectivism (due to the mix of vertical and horizontal cultural transmission, or the observation in several countries of increasing individualism (which is transmitted horizontally and therefore rapidly despite little corresponding change in collectivism (which is transmitted partly vertically and therefore more slowly. Further consideration of cultural transmission mechanisms, in conjunction with the study of

  11. How Do People Become W.E.I.R.D.? Migration Reveals the Cultural Transmission Mechanisms Underlying Variation in Psychological Processes.

    Science.gov (United States)

    Mesoudi, Alex; Magid, Kesson; Hussain, Delwar

    2016-01-01

    Cultural psychologists have shown that people from Western, Educated, Industrialised, Rich, Democratic (WEIRD) countries often exhibit different psychological processing to people from less-WEIRD countries. The former exhibit more individualistic and less collectivistic social orientation, and more analytic and less holistic cognition, than non-Westerners. Yet the mechanisms responsible for maintaining this cultural variation are unclear. Immigration is an ideal 'natural experiment' for uncovering such mechanisms. We used a battery of psychological measures previously shown to vary cross-culturally to compare the social orientation and cognitive style of 286 residents of East London from three cultural backgrounds: (i) 1st-generation British Bangladeshi immigrants; (ii) 2nd-generation British Bangladeshis raised in the UK to Bangladeshi-raised parents; and (iii) non-migrants whose parents were born and raised in the UK. Model comparison revealed that individualism and dispositional attribution, typical of Western societies, are driven primarily by horizontal cultural transmission (e.g. via mass media), with parents and other family members having little or no effect, while collectivism, social closeness and situational attribution were driven by a mix of vertical/oblique cultural transmission (e.g. via family contact) and horizontal cultural transmission. These individual-level transmission dynamics can explain hitherto puzzling population-level phenomena, such as the partial acculturation of 2nd-generation immigrants on measures such as collectivism (due to the mix of vertical and horizontal cultural transmission), or the observation in several countries of increasing individualism (which is transmitted horizontally and therefore rapidly) despite little corresponding change in collectivism (which is transmitted partly vertically and therefore more slowly). Further consideration of cultural transmission mechanisms, in conjunction with the study of migrant

  12. Bioinformatics analysis and prediction for structure and function of nitric oxide synthase and similar proteins from Plasmodium berghei

    Institute of Scientific and Technical Information of China (English)

    Zhigang Fan; Gang Lv; Lingmin Zhang; Xiufeng Gan; Qiang Wu; Saifeng Zhong; Guogang Yan; Guifen Lin

    2011-01-01

    Objective: To search and analyze nitric oxide synthase (NOS) and similar proteins fromPlasmodium berghei(Pb). Methods: The structure and function of nitric oxide synthase and similar proteins from Plasmodium berghei were analyzed and predicted by bioinformatics. Results: PbNOS were not available, but nicotinamide adenine dinucleotide 2’-phosphate reduced tetrasodium (NADPH)-cytochrome p450 reductase(CPR) were gained. PbCPR was in the nucleus of Plasmodium berghei, while 134aa-229aa domain was localize in nucleolar organizer. The amino acids sequence of PbCPR had the closest genetic relationship with Plasmodium vivax showing a 73% homology. The tertiary structure of PbCPR displayed the forcep-shape with wings, but no wings existed in the tertiary structure of its’ host, Mus musculus(Mm). 137aa-200aa, 201aa-218aa, 220aa-230aa, 232aa-248, 269aa-323aa, 478aa-501aa and 592aa-606aa domains of PbCPR showed no homology with MmCPRs’, and all domains were exposed on the surface of the protein. Conclusions: NOS can’t be found in Plasmodium berghei and other Plasmodium species. PbCPR may be a possible resistance site of antimalarial drug, and the targets of antimalarial drug and vaccine. It may be also one of the mechanisms of immune evasion. This study on Plasmodium berghei may be more suitable to Plasmodium vivax. And137aa-200aa, 201aa-218aa, 220aa-230aa, 232aa-248, 269aa-323aa, 478aa-501aa and 592aa-606aa domains ofPb CPR are more ideal targets of antimalarial drug and vaccine.

  13. An essential role of the basal body protein SAS-6 in Plasmodium male gamete development and malaria transmission.

    Science.gov (United States)

    Marques, Sara R; Ramakrishnan, Chandra; Carzaniga, Raffaella; Blagborough, Andrew M; Delves, Michael J; Talman, Arthur M; Sinden, Robert E

    2015-02-01

    Gametocytes are the sole Plasmodium parasite stages that infect mosquitoes; therefore development of functional gametes is required for malaria transmission. Flagellum assembly of the Plasmodium male gamete differs from that of most other eukaryotes in that it is intracytoplasmic but retains a key conserved feature: axonemes assemble from basal bodies. The centriole/basal body protein SAS-6 normally regulates assembly and duplication of these organelles and its depletion causes severe flagellar/ciliary abnormalities in a diverse array of eukaryotes. Since basal body and flagellum assembly are intimately coupled to male gamete development in Plasmodium, we hypothesized that SAS-6 disruption may cause gametogenesis defects and perturb transmission. We show that Plasmodium berghei sas6 knockouts display severely abnormal male gametogenesis presenting reduced basal body numbers, axonemal assembly defects and abnormal nuclear allocation. The defects in gametogenesis reduce fertilization and render Pbsas6 knockouts less infectious to mosquitoes. Additionally, we show that lack of Pbsas6 blocks transmission from mosquito to vertebrate host, revealing an additional yet undefined role in ookinete to sporulating oocysts transition. These findings underscore the vulnerability of the basal body/SAS-6 to malaria transmission blocking interventions.

  14. [Ultrastructure of diatom Synedra acus subsp. radians as revealed by transmission electron microscopy after mild silica dissolution].

    Science.gov (United States)

    Bedoshvili, E D; Likhoshvaĭ, E V; Grachev, M A

    2007-01-01

    A diatom Synedra acus subsp. radians (Kütz.) Skabitsch. has been studied by transmission electron microscopy. Examination of ultrathin sections demonstrated that silica dissolution in ammonium fluoride pH 5 under mild conditions leaves the key ultrastructural elements intact. The ultrastructure and arrangement of the cell organelles was studied during ontogeny. Silicalemma-surrounded silica deposition vesicles (SDVs) with maturating daughter valves and forming girdle bands have been identified. This method of SDV visualization offers considerable advantages over the standard approach without silica dissolution.

  15. Exoplanetary atmospheric sodium revealed by the orbital motion. Narrow-band transmission spectroscopy of HD 189733b with UVES

    CERN Document Server

    Khalafinejad, S; Hoeijmakers, H J; Zhou, G; Klocova, T; Schmitt, J H M M; Dreizler, S; Lopez-Morales, M; Husser, T -O; Schmidt, T O B; Collet, R

    2016-01-01

    During primary transits, the spectral signatures of an exoplanet atmosphere can be measured using transmission spectroscopy. The goal of this work is to accurately measure the atomspheric sodium absorption light curve in HD189733b, correcting for the effects of stellar differential limb-darkening, stellar activity and a "bump" caused by the changing radial velocity of the exoplanet. In fact, due to the high cadence and quality of our data, it is the first time that the last feature can be detected even by visual inspection. We use 244 high-resolution optical spectra taken by the UVES instrument mounted at the VLT. Our observations cover a full transit of HD 189733b, with a cadence of 45 seconds. To probe the transmission spectrum of sodium we produce excess light- curves integrating the stellar flux in passbands of 1 \\AA, 1.5 \\AA, and 3 \\AA inside the core of each sodium D-line. We model the effects of external sources on the excess light-curves, which correspond to an observed stellar flare beginning close t...

  16. Sex determination by SRY PCR and sequencing of Tasmanian devil facial tumour cell lines reveals non-allograft transmission.

    Science.gov (United States)

    Cui, Xianlan; Wang, Yunfeng; Hua, Bobby; Miller, Webb; Zhao, Yan; Cui, Hongyu; Kong, Xiangang

    2016-05-20

    Devil facial tumour disease (DFTD) is an infectious tumour disease and was hypothesised to be transmitted by allograft during biting based on two cytogenetic findings of DFTD tumours in 2006. It was then believed that DFTD tumours were originally from a female devil. In this study the devil sex-determining region Y (SRY) gene was PCR amplified and sequenced, and six pairs of devil SRY PCR primers were used for detection of devil SRY gene fragments in purified DFTD tumour cell lines. Using three pairs of devil SRY PCR primers, devil SRY gene sequence was detected by PCR and sequencing in genomic DNA of DFTD tumour cell lines from six male devils, but not from six female devils. Four out of six DFTD tumour cell lines from male devils contained nucleotides 288-482 of the devil SRY gene, and another two DFTD tumour cell lines contained nucleotides 381-577 and 493-708 of the gene, respectively. These results indicate that the different portions of the SRY gene in the DFTD tumours of the male devils were originally from the male hosts, rejecting the currently believed DFTD allograft transmission theory. The reasons why DFTD transmission was incorrectly defined as allograft are discussed.

  17. Jupiter as an exoplanet: UV to NIR transmission spectrum reveals hazes, a Na layer and possibly stratospheric H2O-ice clouds

    CERN Document Server

    Montañes-Rodriguez, P; Palle, E; Lopez-Puertas, M; Garcia-Melendo, E

    2015-01-01

    Currently, the analysis of transmission spectra is the most successful technique to probe the chemical composition of exoplanet atmospheres. But the accuracy of these measurements is constrained by observational limitations and the diversity of possible atmospheric compositions. Here we show the UV-VIS-IR transmission spectrum of Jupiter, as if it were a transiting exoplanet, obtained by observing one of its satellites, Ganymede, while passing through Jupiter's shadow i.e., during a solar eclipse from Ganymede. The spectrum shows strong extinction due to the presence of clouds (aerosols) and haze in the atmosphere, and strong absorption features from CH4. More interestingly, the comparison with radiative transfer models reveals a spectral signature, which we attribute here to a Jupiter stratospheric layer of crystalline H2O ice. The atomic transitions of Na are also present. These results are relevant for the modeling and interpretation of giant transiting exoplanets. They also open a new technique to explore...

  18. Discovery and targeted LC-MS/MS of purified polerovirus reveals differences in the virus-host interactome associated with altered aphid transmission.

    Science.gov (United States)

    Cilia, Michelle; Peter, Kari A; Bereman, Michael S; Howe, Kevin; Fish, Tara; Smith, Dawn; Gildow, Fredrick; MacCoss, Michael J; Thannhauser, Theodore W; Gray, Stewart M

    2012-01-01

    Circulative transmission of viruses in the Luteoviridae, such as cereal yellow dwarf virus (CYDV), requires a series of precisely orchestrated interactions between virus, plant, and aphid proteins. Natural selection has favored these viruses to be retained in the phloem to facilitate acquisition and transmission by aphids. We show that treatment of infected oat tissue homogenate with sodium sulfite reduces transmission of the purified virus by aphids. Transmission electron microscopy data indicated no gross change in virion morphology due to treatments. However, treated virions were not acquired by aphids through the hindgut epithelial cells and were not transmitted when injected directly into the hemocoel. Analysis of virus preparations using nanoflow liquid chromatography coupled to tandem mass spectrometry revealed a number of host plant proteins co-purifying with viruses, some of which were lost following sodium sulfite treatment. Using targeted mass spectrometry, we show data suggesting that several of the virus-associated host plant proteins accumulated to higher levels in aphids that were fed on CYDV-infected plants compared to healthy plants. We propose two hypotheses to explain these observations, and these are not mutually exclusive: (a) that sodium sulfite treatment disrupts critical virion-host protein interactions required for aphid transmission, or (b) that host infection with CYDV modulates phloem protein expression in a way that is favorable for virus uptake by aphids. Importantly, the genes coding for the plant proteins associated with virus may be examined as targets in breeding cereal crops for new modes of virus resistance that disrupt phloem-virus or aphid-virus interactions.

  19. Discovery and targeted LC-MS/MS of purified polerovirus reveals differences in the virus-host interactome associated with altered aphid transmission.

    Directory of Open Access Journals (Sweden)

    Michelle Cilia

    Full Text Available Circulative transmission of viruses in the Luteoviridae, such as cereal yellow dwarf virus (CYDV, requires a series of precisely orchestrated interactions between virus, plant, and aphid proteins. Natural selection has favored these viruses to be retained in the phloem to facilitate acquisition and transmission by aphids. We show that treatment of infected oat tissue homogenate with sodium sulfite reduces transmission of the purified virus by aphids. Transmission electron microscopy data indicated no gross change in virion morphology due to treatments. However, treated virions were not acquired by aphids through the hindgut epithelial cells and were not transmitted when injected directly into the hemocoel. Analysis of virus preparations using nanoflow liquid chromatography coupled to tandem mass spectrometry revealed a number of host plant proteins co-purifying with viruses, some of which were lost following sodium sulfite treatment. Using targeted mass spectrometry, we show data suggesting that several of the virus-associated host plant proteins accumulated to higher levels in aphids that were fed on CYDV-infected plants compared to healthy plants. We propose two hypotheses to explain these observations, and these are not mutually exclusive: (a that sodium sulfite treatment disrupts critical virion-host protein interactions required for aphid transmission, or (b that host infection with CYDV modulates phloem protein expression in a way that is favorable for virus uptake by aphids. Importantly, the genes coding for the plant proteins associated with virus may be examined as targets in breeding cereal crops for new modes of virus resistance that disrupt phloem-virus or aphid-virus interactions.

  20. Variant-specific immunity to Plasmodium berghei in pregnant mice

    DEFF Research Database (Denmark)

    Megnekou, Rosette; Hviid, Lars; Staalsoe, Trine

    2009-01-01

    We have investigated the immunological basis of pregnancy-related Plasmodium berghei recrudescence in immune mice with substantial preexisting immunity. Specifically, we examined the relevance of this experimental model to the study of pregnancy-associated malaria (PAM) caused by P. falciparum...... in women with substantial preexisting protective immunity. We used mice with immunity induced prior to pregnancy and employed flow cytometry to assess their levels of immunoglobulin G (IgG) recognizing antigens on the surfaces of infected erythrocytes (IEs) in plasma. After immunization, the mice did...... not possess IgG specific for antigens on IEs obtained during pregnancy-related recrudescence but they acquired recrudescence-specific IgG over the course of several pregnancies and recrudescences. In contrast, levels of antibodies recognizing IEs from nonpregnant mice did not increase with increasing parity...

  1. 4(1H)-Quinolones with liver stage activity against Plasmodium berghei.

    Science.gov (United States)

    Lacrue, Alexis N; Sáenz, Fabián E; Cross, R Matthew; Udenze, Kenneth O; Monastyrskyi, Andrii; Stein, Steven; Mutka, Tina S; Manetsch, Roman; Kyle, Dennis E

    2013-01-01

    With the exception of primaquine, tafenoquine, and atovaquone, there are very few antimalarials that target liver stage parasites. In this study, a transgenic Plasmodium berghei parasite (1052Cl1; PbGFP-Luc(con)) that expresses luciferase was used to assess the anti-liver stage parasite activity of ICI 56,780, a 7-(2-phenoxyethoxy)-4(1H)-quinolone (PEQ), as well as two 3-phenyl-4(1H)-quinolones (P4Q), P4Q-146 and P4Q-158, by using bioluminescent imaging (BLI). Results showed that all of the compounds were active against liver stage parasites; however, ICI 56,780 and P4Q-158 were the most active, with low nanomolar activity in vitro and causal prophylactic activity in vivo. This potent activity makes these compounds ideal candidates for advancement as novel antimalarials.

  2. Anopheles gambiae eicosanoids modulate Plasmodium berghei survival from oocyst to salivary gland invasion

    Directory of Open Access Journals (Sweden)

    Susana Ramos

    2014-08-01

    Full Text Available Eicosanoids affect the immunity of several pathogen/insect models, but their role on the Anopheles gambiae response to Plasmodium is still unknown. Plasmodium berghei-infected mosquitoes were injected with an eicosanoid biosynthesis inhibitor, indomethacin (IN, or a substrate, arachidonic acid (AA, at day 7 or day 12 post-infection (p.i.. Salivary gland invasion was evaluated by sporozoite counts at day 21 p.i. IN promoted infection upon sporozoite release from oocysts, but inhibited infection when sporozoites were still maturing within the oocysts, as observed by a reduction in the number of sporozoites reaching the salivary glands. AA treatment had the opposite effect. We show for the first time that An. gambiae can modulate parasite survival through eicosanoids by exerting an antagonistic or agonistic effect on the parasite, depending on its stage of development.

  3. Anopheles gambiae eicosanoids modulate Plasmodium berghei survival from oocyst to salivary gland invasion.

    Science.gov (United States)

    Ramos, Susana; Custódio, Ana; Silveira, Henrique

    2014-08-01

    Eicosanoids affect the immunity of several pathogen/insect models, but their role on the Anopheles gambiae response to Plasmodium is still unknown. Plasmodium berghei-infected mosquitoes were injected with an eicosanoid biosynthesis inhibitor, indomethacin (IN), or a substrate, arachidonic acid (AA), at day 7 or day 12 post-infection (p.i.). Salivary gland invasion was evaluated by sporozoite counts at day 21 p.i. IN promoted infection upon sporozoite release from oocysts, but inhibited infection when sporozoites were still maturing within the oocysts, as observed by a reduction in the number of sporozoites reaching the salivary glands. AA treatment had the opposite effect. We show for the first time that An. gambiae can modulate parasite survival through eicosanoids by exerting an antagonistic or agonistic effect on the parasite, depending on its stage of development.

  4. Effects of levamisole on experimental infections by Plasmodium berghei in mice

    Directory of Open Access Journals (Sweden)

    Enrique Melendez C.

    1987-12-01

    Full Text Available Levamisole (phenylimidothiazol, considered a strong immunostimulant, when administered to healthy Swiss mice did not cause a significant increase in -the weight of their thymus, liver and spleen, even though the drug was used at different times before removing such organs. High doses ofdrug used in the 4-day prophylactic scheme had no antimalarial effect. However, when given to malaria infected mice 24 hours before, at the same time, and 24 hours after the inoculation of a chloroquine-sensitive or a chloroquine-resistant strain of Plasmodium berghei small doses of the drug induced a somewhat decreased parasitemia, the dose of 1 mg/kg body weight before the inoculum being the best scheme. The mortality rates by malaria in the levamisole treated groups were also delayed although all mice finally died. The data suggest that levamisole may display a stimulant effect on the depressed immune response caused by malaria.

  5. Enzymatic Characterization of Recombinant Food Vacuole Plasmepsin 4 from the Rodent Malaria Parasite Plasmodium berghei.

    Directory of Open Access Journals (Sweden)

    Peng Liu

    Full Text Available The rodent malaria parasite Plasmodium berghei is a practical model organism for experimental studies of human malaria. Plasmepsins are a class of aspartic proteinase isoforms that exert multiple pathological effects in malaria parasites. Plasmepsins residing in the food vacuole (FV of the parasite hydrolyze hemoglobin in red blood cells. In this study, we cloned PbPM4, the FV plasmepsin gene of P. berghei that encoded an N-terminally truncated pro-segment and the mature enzyme from genomic DNA. We over-expressed this PbPM4 zymogen as inclusion bodies (IB in Escherichia coli, and purified the protein following in vitro IB refolding. Auto-maturation of the PbPM4 zymogen to mature enzyme was carried out at pH 4.5, 5.0, and 5.5. Interestingly, we found that the PbPM4 zymogen exhibited catalytic activity regardless of the presence of the pro-segment. We determined the optimal catalytic conditions for PbPM4 and studied enzyme kinetics on substrates and inhibitors of aspartic proteinases. Using combinatorial chemistry-based peptide libraries, we studied the active site preferences of PbPM4 at subsites S1, S2, S3, S1', S2' and S3'. Based on these results, we designed and synthesized a selective peptidomimetic compound and tested its inhibition of PbPM4, seven FV plasmepsins from human malaria parasites, and human cathepsin D (hcatD. We showed that this compound exhibited a >10-fold selectivity to PbPM4 and human malaria parasite plasmepsin 4 orthologs versus hcatD. Data from this study furthesr our understanding of enzymatic characteristics of the plasmepsin family and provides leads for anti-malarial drug design.

  6. In Vivo Antimalarial Activity of Annona muricata Leaf Extract in Mice Infected with Plasmodium berghei.

    Science.gov (United States)

    Somsak, Voravuth; Polwiang, Natsuda; Chachiyo, Sukanya

    2016-01-01

    Malaria is one of the most important infectious diseases in the world. The choice for the treatment is highly limited due to drug resistance. Hence, finding the new compounds to treat malaria is urgently needed. The present study was attempted to evaluate the antimalarial activity of the Annona muricata aqueous leaf extract in Plasmodium berghei infected mice. Aqueous leaf extract of A. muricata was prepared and tested for acute toxicity in mice. For efficacy test in vivo, standard 4-day suppressive test was carried out. ICR mice were inoculated with 10(7) parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection. The extracts (100, 500, and 1000 mg/kg) were then given orally by gavage once a day for 4 consecutive days. Parasitemia, percentage of inhibition, and packed cell volume were subsequently calculated. Chloroquine (10 mg/kg) was given to infected mice as positive control while untreated control was given only distilled water. It was found that A. muricata aqueous leaf extract at doses of 100, 500, and 1000 mg/kg resulted in dose dependent parasitemia inhibition of 38.03%, 75.25%, and 85.61%, respectively. Survival time was prolonged in infected mice treated with the extract. Moreover, no mortality to mice was observed with this extract up to a dose of 4000 mg/kg. In conclusion, the A. muricata aqueous leaf extract exerted significant antimalarial activity with no toxicity and prolonged survival time. Therefore, this extract might contain potential lead molecule for the development of a new drug for malaria treatment.

  7. Efeito de Momordica charantia I. Em camundongos infectados por Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Helene Mariko Ueno

    1996-10-01

    Full Text Available A Organização Mundial de Saúde (OMS citou a malãria como um dos principais problemas de saúde no Brasil e no terceiro mundo, onde 80% da população recorre à medicina tradicional (popular para sanar vários problemas de assistência médica primária. No que se refere à malária, seu tratamento e controle têm sido dificultados devido às cepas resistentes às drogas comumente utilizadas. Isso torna urgente a busca de novas drogas antimaláncas. Sabe-se que a população utiliza-se de diferentes plantas para o tratamento e cura de vários males, inclusive a malãria. Neste trabalho nos propusemos reavaliar o efeito de Momordica charantia L. (Cucurbitaceae sobre camundongos infectados por Plasmodium berghei. A planta foi testada sob a forma de extratos aquoso e etanólico, na dose de lOOOmg por kg cle peso coipóreo do camundongo, ministrado por via oral, por cinco dias consecutivos da infecção (2º ao 6º. O efeito foi avaliado em função da parasitemia e da sobrevida dos animais. Embora a população indique e utilize essa planta na malária humana, nos ensaios deste trabalho, nas condições do experimento, os extratos de M. charantia não apresentaram atividade satisfatória contra o P. berghei.

  8. Chikungunya virus neutralization antigens and direct cell-to-cell transmission are revealed by human antibody-escape mutants.

    Directory of Open Access Journals (Sweden)

    Chia Yin Lee

    2011-12-01

    Full Text Available Chikungunya virus (CHIKV is an alphavirus responsible for numerous epidemics throughout Africa and Asia, causing infectious arthritis and reportedly linked with fatal infections in newborns and elderly. Previous studies in animal models indicate that humoral immunity can protect against CHIKV infection, but despite the potential efficacy of B-cell-driven intervention strategies, there are no virus-specific vaccines or therapies currently available. In addition, CHIKV has been reported to elicit long-lasting virus-specific IgM in humans, and to establish long-term persistence in non-human primates, suggesting that the virus might evade immune defenses to establish chronic infections in man. However, the mechanisms of immune evasion potentially employed by CHIKV remain uncharacterized. We previously described two human monoclonal antibodies that potently neutralize CHIKV infection. In the current report, we have characterized CHIKV mutants that escape antibody-dependent neutralization to identify the CHIKV E2 domain B and fusion loop "groove" as the primary determinants of CHIKV interaction with these antibodies. Furthermore, for the first time, we have also demonstrated direct CHIKV cell-to-cell transmission, as a mechanism that involves the E2 domain A and that is associated with viral resistance to antibody-dependent neutralization. Identification of CHIKV sub-domains that are associated with human protective immunity, will pave the way for the development of CHIKV-specific sub-domain vaccination strategies. Moreover, the clear demonstration of CHIKV cell-to-cell transmission and its possible role in the establishment of CHIKV persistence, will also inform the development of future anti-viral interventions. These data shed new light on CHIKV-host interactions that will help to combat human CHIKV infection and inform future studies of CHIKV pathogenesis.

  9. Genome analysis of a transmissible lineage of pseudomonas aeruginosa reveals pathoadaptive mutations and distinct evolutionary paths of hypermutators.

    Directory of Open Access Journals (Sweden)

    Rasmus Lykke Marvig

    Full Text Available Genome sequencing of bacterial pathogens has advanced our understanding of their evolution, epidemiology, and response to antibiotic therapy. However, we still have only a limited knowledge of the molecular changes in in vivo evolving bacterial populations in relation to long-term, chronic infections. For example, it remains unclear what genes are mutated to facilitate the establishment of long-term existence in the human host environment, and in which way acquisition of a hypermutator phenotype with enhanced rates of spontaneous mutations influences the evolutionary trajectory of the pathogen. Here we perform a retrospective study of the DK2 clone type of P. aeruginosa isolated from Danish patients suffering from cystic fibrosis (CF, and analyze the genomes of 55 bacterial isolates collected from 21 infected individuals over 38 years. Our phylogenetic analysis of 8,530 mutations in the DK2 genomes shows that the ancestral DK2 clone type spread among CF patients through several independent transmission events. Subsequent to transmission, sub-lineages evolved independently for years in separate hosts, creating a unique possibility to study parallel evolution and identification of genes targeted by mutations to optimize pathogen fitness (pathoadaptive mutations. These genes were related to antibiotic resistance, the cell envelope, or regulatory functions, and we find that the prevalence of pathoadaptive mutations correlates with evolutionary success of co-evolving sub-lineages. The long-term co-existence of both normal and hypermutator populations enabled comparative investigations of the mutation dynamics in homopolymeric sequences in which hypermutators are particularly prone to mutations. We find a positive exponential correlation between the length of the homopolymer and its likelihood to acquire mutations and identify two homopolymer-containing genes preferentially mutated in hypermutators. This homopolymer facilitated differential

  10. Genomic characterization of a rotavirus G8P[1] detected in a child with diarrhea reveal direct animal-to-human transmission.

    Science.gov (United States)

    Martinez, Magaly; Phan, Tung Gia; Galeano, Maria Eugenia; Russomando, Graciela; Parreno, Viviana; Delwart, Eric; Parra, Gabriel I

    2014-10-01

    Group A rotavirus is a major cause of severe gastroenteritis in children and young animals. During a retrospective analysis of samples collected from Paraguayan children under 5 years old with diarrhea, and previously negative for rotavirus and norovirus, we detected the presence of bovine rotavirus sequences by viral metagenomics. Nucleic acid was extracted direct from stool sample and determined to be G8P[1]. The genomic analyzes revealed that the strain presents an Artiodactyl-like genome (G8-P[1]-I2-R2-C2-M1-Ax-N2-T6-E12-H3) suggesting a direct animal-to-human transmission.

  11. Dislocation substructure of mantle-derived olivine as revealed by selective chemical etching and transmission electron microscopy

    Science.gov (United States)

    Kirby, S.H.; Wegner, M.W.

    1978-01-01

    Cleaved and mechanically polished surfaces of olivine from peridotite xenoliths from San Carlos, Arizona, were chemically etched using the techniques of Wegner and Christie (1974). Dislocation etch pits are produced on all surface orientations and they tend to be preferentially aligned along the traces of subgrain boundaries, which are approximately parallel to (100), (010), and (001). Shallow channels were also produced on (010) surfaces and represent dislocations near the surface that are etched out along their lengths. The dislocation etch channel loops are often concentric, and emanate from (100) subgrain boundaries, which suggests that dislocation sources are in the boundaries. Data on subgrain misorientation and dislocation line orientation and arguments based on subgrain boundary energy minimization are used to characterize the dislocation structures of the subgrain boundaries. (010) subgrain boundaries are of the twist type, composed of networks of [100] and [001] screw dislocations. Both (100) and (001) subgrain boundaries are tilt walls composed of arrays of edge dislocation with Burgers vectors b=[100] and [001], respectively. The inferred slip systems are {001} ???100???, {100} ???001???, and {010} ???100??? in order of diminishing importance. Exploratory transmission electron microscopy is in accord with these identifications. The flow stresses associated with the development of the subgrain structure are estimated from the densities of free dislocations and from the subgrain dimensions. Inferred stresses range from 35 to 75 bars using the free dislocation densities and 20 to 100 bars using the subgrain sizes. ?? 1978 Springer-Verlag.

  12. Evolution and Function of Dinosaur Teeth at Ultramicrostructural Level Revealed Using Synchrotron Transmission X-ray Microscopy

    Science.gov (United States)

    Wang, Chun-Chieh; Song, Yen-Fang; Song, Sheng-Rong; Ji, Qiang; Chiang, Cheng-Cheng; Meng, Qingjin; Li, Haibing; Hsiao, Kiko; Lu, Yi-Chia; Shew, Bor-Yuan; Huang, Timothy; Reisz, Robert R.

    2015-01-01

    The relationship between tooth form and dietary preference is a crucial issue in vertebrate evolution. However, the mechanical properties of a tooth are influenced not only by its shape but also by its internal structure. Here, we use synchrotron transmission X-ray microscopy to examine the internal microstructures of multiple dinosaur teeth within a phylogenetic framework. We found that the internal microstructures of saurischian teeth are very different from advanced ornithischian teeth, reflecting differences in dental developmental strategies. The three-tissue composition (enamel–mantle dentin–bulk dentin) near the dentinoenamel junction (DEJ) in saurischian teeth represents the primitive condition of dinosaur teeth. Mantle dentin, greatly reduced or absent from DEJ in derived ornithischian teeth, is a key difference between Saurischia and Ornithischia. This may be related to the derived herbivorous feeding behavior of ornithischians, but interestingly, it is still retained in the herbivorous saurischian sauropods. The protective functions of mantle dentin with porous microstructures between enamel and bulk dentin inside typical saurischian teeth are also discussed using finite-element analysis method. Evolution of the dental modifications in ornithischian dinosaurs, with the absence of mantle dentin, may be related to changes in enamel characteristics with enamel spindles extending through the DEJ. PMID:26512629

  13. Smectite flocculation structure modified by Al13 macro-molecules--as revealed by the transmission X-ray microscopy (TXM).

    Science.gov (United States)

    Zbik, Marek S; Martens, Wayde N; Frost, Ray L; Song, Yen-Fang; Chen, Yi-Ming; Chen, Jian-Hua

    2010-05-01

    The aggregate structure which occurs in aqueous smectitic suspensions is responsible for poor water clarification, difficulties in sludge dewatering and the unusual rheological behaviour of smectite rich soils. These macroscopic properties are dictated by the 3D structural arrangement of smectite finest fraction within flocculated aggregates. Here, we report results from a relatively new technique, transmission X-ray microscopy (TXM), which makes it possible to investigate the internal structure and 3D tomographic reconstruction of the smectite clay aggregates modified by Al(13) Keggin macro-molecule [Al(13)(O)(4)(OH)(24)(H(2)O)(12)](7+). Three different treatment methods were shown resulted in three different micro-structural environments of the resulting flocculation. In case of smectite sample prepared in Methods 1 and 3 particles fall into the primary minimum where Van der Waals forces act between FF oriented smectite flakes and aggregates become approach irreversible flocculation. In case of sample prepared using Method 2, particles contacting by edges (EE) and edge to face (EF) orientation fell into secondary minimum and weak flocculation resulted in severe gelation and formation of the micelle-like texture in fringe superstructure, which was first time observed in smectite based gel.

  14. Genetic Characterization of Plasmodium Putative Pantothenate Kinase Genes Reveals Their Essential Role in Malaria Parasite Transmission to the Mosquito

    Science.gov (United States)

    Hart, Robert J.; Cornillot, Emmanuel; Abraham, Amanah; Molina, Emily; Nation, Catherine S.; Ben Mamoun, Choukri; Aly, Ahmed S. I.

    2016-01-01

    The metabolic machinery for the biosynthesis of Coenzyme A (CoA) from exogenous pantothenic acid (Vitamin B5) has long been considered as an excellent target for the development of selective antimicrobials. Earlier studies in the human malaria parasite Plasmodium falciparum have shown that pantothenate analogs interfere with pantothenate phosphorylation and block asexual blood stage development. Although two eukaryotic-type putative pantothenate kinase genes (PanK1 and PanK2) have been identified in all malaria parasite species, their role in the development of Plasmodium life cycle stages remains unknown. Here we report on the genetic characterization of PanK1 and PanK2 in P. yoelii. We show that P. yoelii parasites lacking either PanK1 or PanK2 undergo normal asexual stages development and sexual stages differentiation, however they are severely deficient in ookinete, oocyst and sporozoite formation inside the mosquito vector. Quantitative transcriptional analyses in wild-type and knockout parasites demonstrate an important role for these genes in the regulation of expression of other CoA biosynthesis genes. Together, our data provide the first genetic evidence for the importance of the early steps of pantothenate utilization in the regulation of CoA biosynthesis and malaria parasite transmission to Anopheles mosquitoes. PMID:27644319

  15. Cryogenic transmission electron microscopy of recombinant tuberculosis vaccine antigen with anionic liposomes reveals formation of flattened liposomes

    Directory of Open Access Journals (Sweden)

    Fox CB

    2014-03-01

    Full Text Available Christopher B Fox,1 Sean K Mulligan,2 Joyce Sung,2 Quinton M Dowling,1 H W Millie Fung,1 Thomas S Vedvick,1 Rhea N Coler1 1Infectious Disease Research Institute, Seattle, WA, USA; 2NanoImaging Services, La Jolla, CA, USA Abstract: Development of lipid-based adjuvant formulations to enhance the immunogenicity of recombinant vaccine antigens is a focus of modern vaccine research. Characterizing interactions between vaccine antigens and formulation excipients is important for establishing compatibility between the different components and optimizing vaccine stability and potency. Cryogenic transmission electron microscopy (TEM is a highly informative analytical technique that may elucidate various aspects of protein- and lipid-based structures, including morphology, size, shape, and phase structure, while avoiding artifacts associated with staining-based TEM. In this work, cryogenic TEM is employed to characterize a recombinant tuberculosis vaccine antigen, an anionic liposome formulation, and antigen–liposome interactions. By performing three-dimensional tomographic reconstruction analysis, the formation of a population of protein-containing flattened liposomes, not present in the control samples, was detected. It is shown that cryogenic TEM provides unique information regarding antigen–liposome interactions not detectable by light-scattering-based methods. Employing a suite of complementary analytical techniques is important to fully characterize interactions between vaccine components. Keywords: vaccine adjuvant; cryo-TEM; antigen-adjuvant interactions; vaccine physical characterization; vaccine formulation morphology; 3D tomographic reconstruction

  16. Evolution and Function of Dinosaur Teeth at Ultramicrostructural Level Revealed Using Synchrotron Transmission X-ray Microscopy.

    Science.gov (United States)

    Wang, Chun-Chieh; Song, Yen-Fang; Song, Sheng-Rong; Ji, Qiang; Chiang, Cheng-Cheng; Meng, Qingjin; Li, Haibing; Hsiao, Kiko; Lu, Yi-Chia; Shew, Bor-Yuan; Huang, Timothy; Reisz, Robert R

    2015-10-29

    The relationship between tooth form and dietary preference is a crucial issue in vertebrate evolution. However, the mechanical properties of a tooth are influenced not only by its shape but also by its internal structure. Here, we use synchrotron transmission X-ray microscopy to examine the internal microstructures of multiple dinosaur teeth within a phylogenetic framework. We found that the internal microstructures of saurischian teeth are very different from advanced ornithischian teeth, reflecting differences in dental developmental strategies. The three-tissue composition (enamel-mantle dentin-bulk dentin) near the dentinoenamel junction (DEJ) in saurischian teeth represents the primitive condition of dinosaur teeth. Mantle dentin, greatly reduced or absent from DEJ in derived ornithischian teeth, is a key difference between Saurischia and Ornithischia. This may be related to the derived herbivorous feeding behavior of ornithischians, but interestingly, it is still retained in the herbivorous saurischian sauropods. The protective functions of mantle dentin with porous microstructures between enamel and bulk dentin inside typical saurischian teeth are also discussed using finite-element analysis method. Evolution of the dental modifications in ornithischian dinosaurs, with the absence of mantle dentin, may be related to changes in enamel characteristics with enamel spindles extending through the DEJ.

  17. Dendritic cells treated with crude Plasmodium berghei extracts acquire immune-modulatory properties and suppress the development of autoimmune neuroinflammation.

    Science.gov (United States)

    Thomé, Rodolfo; Issayama, Luidy K; Alves da Costa, Thiago; Gangi, Rosária D; Ferreira, Isadora T; Rapôso, Catarina; Lopes, Stefanie C P; da Cruz Höfling, Maria Alice; Costa, Fábio T M; Verinaud, Liana

    2014-10-01

    Dendritic cells (DCs) are professional antigen-presenting cells specifically targeted during Plasmodium infection. Upon infection, DCs show impaired antigen presentation and T-cell activation abilities. In this study, we aimed to evaluate whether cellular extracts obtained from Plasmodium berghei-infected erythrocytes (PbX) modulate DCs phenotypically and functionally and the potential therapeutic usage of PbX-modulated DCs in the control of experimental autoimmune encephalomyelitis (EAE, the mouse model for human multiple sclerosis). We found that PbX-treated DCs have impaired maturation and stimulated the generation of regulatory T cells when cultured with naive T lymphocytes in vitro. When adoptively transferred to C57BL/6 mice the EAE severity was reduced. Disease amelioration correlated with a diminished infiltration of cytokine-producing T cells in the central nervous system as well as the suppression of encephalitogenic T cells. Our study shows that extracts obtained from P. berghei-infected erythrocytes modulate DCs towards an immunosuppressive phenotype. In addition, the adoptive transfer of PbX-modulated DCs was able to ameliorate EAE development through the suppression of specific cellular immune responses towards neuro-antigens. To our knowledge, this is the first study to present evidence that DCs treated with P. berghei extracts are able to control autoimmune neuroinflammation.

  18. Influence of CD4+CD25+ T cells on Plasmodium berghei NK65 infection in BALB/c mice.

    Science.gov (United States)

    Long, Ton That Ai; Nakazawa, Shusuke; Onizuka, Shozaburo; Huaman, Maria Cecilia; Kanbara, Hiroji

    2003-02-01

    CD4(+) T cells co-expressing CD25 (CD4(+)CD25(+) T cells) have been identified as immunoregulatory suppressors modulating autoimmune response. Beside that, autoimmune response was supposed to be associated with malaria infection. Based on these data, we hypothesised that CD4(+)CD25(+) T cells may influence protective immunity to malaria parasites, while suppressing autoimmune response arising throughout the course of malarial infection. To test this possibility, we evaluated the kinetics of CD4(+)CD25(+) T cells during malaria infection and investigated the influence of CD25 depletion by anti-mouse CD25 monoclonal antibody (PC61) on the infection, using a mouse model of premunition to Plasmodium berghei NK65 malaria. The results showed that, during exacerbation of P. berghei NK65 infection, the proportion of CD4(+)CD25(+) T cells among CD4(+) T cells decreased, although that of CD4(+) T cells increased. CD25 depletion clearly delayed the growth of parasitaemia during parasite challenge, particularly in immunised mice. These findings demonstrated that CD4(+)CD25(+) T cells are able to influence protective immunity underlying premunition to P. berghei NK65 parasites.

  19. Pharmacodynamic evaluation for antiplasmodial activity of Holarrhena antidysentrica (Kutaja) and Azadirachta indica (Neemb) in Plasmodium berghei infected mice model

    Institute of Scientific and Technical Information of China (English)

    Jadhav Priyanka; Lal Hingorani; Kshirsagar Nilima

    2013-01-01

    Objective: To investigate in-vivo anti-plasmodial activity of aqueous extracts of plants selected based on the symptomology mentioned in Ayurveda. Methods: The aqueous extracts of Holarrhena antidysentrica (H. antidysentrica) (Kutaja) and Azadirachta indica (A. indica) (Neemb) for their antiplasmodial potential in Plasmodium berghei (P. berghei) infected mice was assessed using Peters four day suppressive test. Both the extracts were administered at 2 dose levels, full dose (1 000 mg/d) and minimized dose (200 mg/d). 106 P. berghei infected RBCs were injected on day ’0’ and treated from day ’0’ till day ’3’ post-infection. Tail blood smears were collected, giemsa stained and analyzed. The mice were observed for survival and parasitemia was assessed till 50% of mice in control survived. Results: It was observed that the percentage of parasitemia increased gradually in all the groups, with maximum in control group (Day 3-35, Day 9-46.98) and minimum in Chloroquine arm (Day 3-14.06, Day 9-19.92). The percentage of parasitemia was compared using Mann-Whitney U test depicting that all test groups exhibited reduction in parasitemia as compared to control (P-value<0.002 for all groups). These groups showed similar percentage of survival as Chloroquine. Conclusions: The present investigation demonstrated the anti-plasmodial effects of H. antidysentrica and A. indica, which are two most commonly used medicinal plants in Ayurved for treatment of fever.

  20. Protection of renal function by four selected plant extracts during Plasmodium berghei infection

    Directory of Open Access Journals (Sweden)

    Adewale Adetutu

    2015-10-01

    Full Text Available Background: Weakening of renal function from reactive oxygen species generated during malaria infection is one of the prominent causes of death in prevalent regions. The potential toxicity of free radical generated by malaria parasites are counteracted by a large number of cytoprotective phytochemicals. Therefore, this study examined the influence of extracts of five selected antimalarial plants (Azadirachta indica, Parquetina nigrescens, Citrus paradisi, and Khaya senigalensis on reduction of inflammation in renal tissue, blood urea nitrogen and creatinine levels during malaria infection using Plasmodium berghei infected Swiss albino mice. For in vivo assay, mice were inoculated with 1 × 107 parasitized erythrocytes and plant extracts were subsequently administered orally at 100 mg/kg body weight once a day for 17 consecutive days. The chemo-suppressive and prophylaxis effects of the plant extracts against P. berghei were investigated and compared with those of standard antimalarial drug, chloroquine. Tail bleeding was performed to check the percentage parasitaemia by making a thin film smear on a slide, stained in Giemsa. The numbers of parasited cells against the unparasitised cells were counted using a microscope. The effect of malaria infection on renal tissue was assessed by histological analysis and measurement of blood urea nitrogen and creatinine levels in plasma. At 100 mg/kg per body weight, aqueous extract of K. senegalensis, A. indica, C. paradisi and P. nigrescens exhibited significant (p<0.05 percentage inhibition and chemo-suppressive effects in comparison with the chloroquine treated mice. The result of the untreated group showed that there was a significant (p<0.05 increase in the level of plasma urea while the level of the groups treated with plants extract stabilized the level of urea and creatinine in the blood. Also there was a pathological lesion on the kidney tissue of untreated group whereas the group treated with

  1. Effects of levamisole on experimental infections by Plasmodium berghei in mice

    Directory of Open Access Journals (Sweden)

    Enrique Melendez C.

    1987-12-01

    Full Text Available Levamisole (phenylimidothiazol, considered a strong immunostimulant, when administered to healthy Swiss mice did not cause a significant increase in -the weight of their thymus, liver and spleen, even though the drug was used at different times before removing such organs. High doses ofdrug used in the 4-day prophylactic scheme had no antimalarial effect. However, when given to malaria infected mice 24 hours before, at the same time, and 24 hours after the inoculation of a chloroquine-sensitive or a chloroquine-resistant strain of Plasmodium berghei small doses of the drug induced a somewhat decreased parasitemia, the dose of 1 mg/kg body weight before the inoculum being the best scheme. The mortality rates by malaria in the levamisole treated groups were also delayed although all mice finally died. The data suggest that levamisole may display a stimulant effect on the depressed immune response caused by malaria.Levamisol (fenilimidotiazol, considerado urn potente imunoestimulante, quando administrado a camundongos suíços não causou aumento significante nos pesos do timo, figado ou baço, apesar de a droga ter sido usada em diferentes tempos antes da remoção desses órgãos. Doses elevadas da droga usadas no esquema profilático de 4 dias não tiveram efeito antimalárico. Entretanto quando dada a camundongos com malária, 24 horas antes, ao mesmo tempo ou 24 horas após inoculação de uma cepa de Plasmodium berghei cloroquina-sensível ou uma cepa cloroquina- resistente o levamisol reduziu, ainda que discretamente, a parasitemia nos grupos tratados, sendo a dose de 1 mg/kg o melhor esquema. Foi observado também atraso na mortalidade por malária nos grupos tratados com o levamisol. No entanto, todos os animais morreram. Os dados sugerem que o levamisol tem efeito imunoestimulante, ainda que discreto, na resposta imune de animais, deprimida pela malária.

  2. JUPITER AS AN EXOPLANET: UV TO NIR TRANSMISSION SPECTRUM REVEALS HAZES, A Na LAYER, AND POSSIBLY STRATOSPHERIC H{sub 2}O-ICE CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Montañés-Rodríguez, Pilar; González-Merino, B.; Pallé, E. [Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, E-38200 La Laguna (Spain); López-Puertas, Manuel [Departamento de Astrofísica, Universidad de La Laguna, Av., Astrofísico Francisco Sánchez, s/n, E-38206 La Laguna (Spain); García-Melendo, E., E-mail: pmr@iac.es [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18080 Granada (Spain)

    2015-03-01

    Currently, the analysis of transmission spectra is the most successful technique to probe the chemical composition of exoplanet atmospheres. However, the accuracy of these measurements is constrained by observational limitations and the diversity of possible atmospheric compositions. Here, we show the UV–VIS–IR transmission spectrum of Jupiter as if it were a transiting exoplanet, obtained by observing one of its satellites, Ganymede, while passing through Jupiter’s shadow, i.e., during a solar eclipse from Ganymede. The spectrum shows strong extinction due to the presence of clouds (aerosols) and haze in the atmosphere and strong absorption features from CH{sub 4}. More interestingly, the comparison with radiative transfer models reveals a spectral signature, which we attribute here to a Jupiter stratospheric layer of crystalline H{sub 2}O ice. The atomic transitions of Na are also present. These results are relevant for the modeling and interpretation of giant transiting exoplanets. They also open a new technique to explore the atmospheric composition of the upper layers of Jupiter’s atmosphere.

  3. Visualization of Malaria Parasites in the Skin Using the Luciferase Transgenic Parasite, Plasmodium berghei.

    Science.gov (United States)

    Matsuoka, Hiroyuki; Tomita, Hiroyuki; Hattori, Ryuta; Arai, Meiji; Hirai, Makoto

    2015-03-01

    We produced a transgenic rodent malaria parasite (Plasmodium berghei) that contained the luciferase gene under a promoter region of elongation factor-1α. These transgenic (TG) parasites expressed luciferase in all stages of their life cycle, as previously reported. However, we were the first to succeed in observing sporozoites as a mass in mouse skin following their deposition by the probing of infective mosquitoes. Our transgenic parasites may have emitted stronger bioluminescence than previous TG parasites. The estimated number of injected sporozoites by mosquitoes was between 34 and 775 (median 80). Since luciferase activity diminished immediately after the death of the parasites, luciferase activity could be an indicator of the existence of live parasites. Our results indicated that sporozoites survived at the probed site for more than 42 hours. We also detected sporozoites in the liver within 15 min of the intravenous injection. Bioluminescence was not observed in the lung, kidney or spleen. We confirmed the observation that the liver was the first organ in which malaria parasites entered and increased in number.

  4. Sex hormones modulate the immune response to Plasmodium berghei ANKA in CBA/Ca mice.

    Science.gov (United States)

    Legorreta-Herrera, Martha; Mosqueda-Romo, Néstor Aarón; Nava-Castro, Karen Elizabeth; Morales-Rodríguez, Ana Laura; Buendía-González, Fidel Orlando; Morales-Montor, Jorge

    2015-07-01

    Susceptibility to malaria differs between females and males, and this sexual dimorphism may have important implications for the effects of vaccines and drugs. However, little is known about the mechanisms mediating these sexual differences. Because the main differences between sexes are dictated by sex hormones, we studied the effect of gonadal steroids on immune responses to malaria in CBA/Ca mice. We decreased sex hormones levels by gonadectomy and evaluated the splenic index and the cells involved in the immune response, including T cells (CD3(+), CD4(+), CD8(+) and NK(+)), B cells and macrophages (Mac-3(+)) in the spleens of female and male mice infected with Plasmodium berghei ANKA. In addition, we measured antibody and cytokine levels in blood. Gonadectomy increased T(+) and B(+) splenic cells in both sexes but increased Mac-3(+) cells only in male mice. By contrast, gonadectomy decreased the NK(+) cell population only in male mice. In general, female mice developed higher antibody levels than males. Contrary to our expectations, gonadectomy increased the synthesis of IgG1, IgG2b, IgG3, and total IgG in female mice, indicating negative regulation of antibody production by female sex hormones. Gonadectomy increased the synthesis of tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) only in female mice, suggesting that female sex hormones have anti-inflammatory properties. This work demonstrates that the levels of sex hormones affect the immune response and should be considered when designing malaria vaccines.

  5. Study on application of high doses plasmodium berghei in cell culture

    Science.gov (United States)

    Spencer, L. M.; De Santis, M.; Davila, J.; Foinquinos, A.; Salcedo, E.; Sajo-Bohus, L.

    2012-02-01

    Malaria, one of the most important infection disease problems in the world, is caused by protozoan parasites of the genus Plasmodium. This disease is responsible for hundreds of the millions of clinical cases and more than one million deaths per year, for this reason, malaria is a priority and the WHO estimates that half of the world population is at risk. In this work we study how the absorbed dose inactivates the parasite (Plasmodium berghei) in rodent model (BALB/c mice), by applying X-ray irradiation. The dose was increased from 10 to 50 Gy in parasitized red blood cells (PRBC) with merozoite stage using in vitro short cultures. Also the reduction of the irradiation effect was determined by intra-peritoneal inoculations of irradiated parasites. Afterwards, the parasitaemia was assessed daily on smears made from tail blood and stained with Giemsa's reagent. Besides, the effect of irradiation was evaluated using an immunological test as indirect immunofluorescence assay (IFA). The results of this study showed that the most effective radiation for inactivation of parasites is about 50 Gy and the immunofluorescence pattern showed a different distribution of the fluorescence on parasites. These results showed direct correlation between the effect of irradiated parasites and parasitaemia in the group of mice infected with RBC after 50 Gy irradiation. Our results indicated that the threshold is between 30 to 50 Gy to inactivate the parasites.

  6. TRPV1 Antagonism by Capsazepine Modulates Innate Immune Response in Mice Infected with Plasmodium berghei ANKA

    Directory of Open Access Journals (Sweden)

    Elizabeth S. Fernandes

    2014-01-01

    Full Text Available Thousands of people suffer from severe malaria every year. The innate immune response plays a determinant role in host’s defence to malaria. Transient receptor potential vanilloid 1 (TRPV1 modulates macrophage-mediated responses in sepsis, but its role in other pathogenic diseases has never been addressed. We investigated the effects of capsazepine, a TRPV1 antagonist, in malaria. C57BL/6 mice received 105 red blood cells infected with Plasmodium berghei ANKA intraperitoneally. Noninfected mice were used as controls. Capsazepine or vehicle was given intraperitoneally for 6 days. Mice were culled on day 7 after infection and blood and spleen cell phenotype and activation were evaluated. Capsazepine decreased circulating but not spleen F4/80+Ly6G+ cell numbers as well as activation of both F4/80+and F4/80+Ly6G+ cells in infected animals. In addition, capsazepine increased circulating but not spleen GR1+ and natural killer (NK population, without interfering with natural killer T (NKT cell numbers and blood NK and NKT activation. However, capsazepine diminished CD69 expression in spleen NKT but not NK cells. Infection increased lipid peroxidation and the release of TNFα and IFNγ, although capsazepine-treated group exhibited lower levels of lipid peroxidation and TNFα. Capsazepine treatment did not affect parasitaemia. Overall, TRPV1 antagonism modulates the innate immune response to malaria.

  7. Isolation of Plasmodium berghei ookinetes in culture using Nycodenz density gradient columns and magnetic isolation

    Directory of Open Access Journals (Sweden)

    Williams Jackie

    2003-11-01

    Full Text Available Abstract Background Large scale in vitro production of the mosquito stages of malaria parasites remains elusive, with only limited success for complete sporogonic development and only one report of development through to infective sporozoites. The initial step in this process is the production, in vitro, of ookinetes from gametocytaemic blood. Methods for isolation of these ookinetes from blood cells have been described; however, in addition to yield often being low, processing time and potential for contamination by erythrocytes remain high. Methods This study compares two procedures for retaining mature ookinetes from blood stage cultures, whilst removing red blood cells and other contaminants prior to further culture of the parasite. The well established method of isolation on Nycodenz cushions is compared with a novel method utilizing the innate magnetic properties of the haem pigment crystals found in the cytoplasm of ookinetes. Results Yield and viability of ookinetes were similar with both isolation methods. However, in our hands magnetic isolation produced a cleaner ookinete preparation much more quickly. Moreover, decreasing the flow rate through the magnetic column could further enhance the yield. Conclusion We recommend the enrichment of an ookinete preparation prior to further culture being performed using the magnetic properties of Plasmodium berghei ookinetes as an alternative to their density. The former technique is faster, removes more erythrocytes, but day-to-day costs are greater.

  8. CSP--a model for in vivo presentation of Plasmodium berghei sporozoite antigens by hepatocytes.

    Directory of Open Access Journals (Sweden)

    Saidou Balam

    Full Text Available One target of protective immunity against the Plasmodium liver stage in BALB/c mice is represented by the circumsporozoite protein (CSP, and mainly involves its recognition by IFN-γ producing specific CD8+T-cells. In a previous in vitro study we showed that primary hepatocytes from BALB/c mice process Plasmodium berghei (Pb CSP (PbCSP and present CSP-derived peptides to specific H-2k(d restricted CD8+T-cells with subsequent killing of the presenting cells. We now extend these observations to an in vivo infection model in which infected hepatocytes and antigen specific T-cell clones are transferred into recipient mice inducing protection from sporozoite (SPZ challenge. In addition, using a similar protocol, we suggest the capacity of hepatocytes in priming of naïve T-cells to provide protection, as further confirmed by induction of protection after depletion of cross-presenting dendritic cells (DCs by cytochrome c (cyt c treatment or using traversal deficient parasites. Our results clearly show that hepatocytes present Plasmodium CSP to specific-primed CD8+T-cells, and could also prime naïve T-cells, leading to protection from infection. These results could contribute to a better understanding of liver stage immune response and design of malaria vaccines.

  9. The novel oxygenated chalcone, 2,4-dimethoxy-4'-butoxychalcone, exhibits potent activity against human malaria parasite Plasmodium falciparum in vitro and rodent parasites Plasmodium berghei and Plasmodium yoelii in vivo

    DEFF Research Database (Denmark)

    Chen, M; Brøgger Christensen, S; Zhai, L;

    1997-01-01

    growth of both a chloroquine-susceptible (3D7) and a chloroquine-resistant (Dd2) strain of Plasmodium falciparum in a [3H]hypoxanthine uptake assay. The in vivo activity of 2,4mbc was tested in mice infected with Plasmodium berghei or Plasmodium yoelii and in rats infected with P. berghei. 2,4mbc...

  10. Local symmetry breaking of a thin crystal structure of β-Si3N4 as revealed by spherical aberration corrected high-resolution transmission electron microscopy images.

    Science.gov (United States)

    Kim, Hwang Su; Zhang, Zaoli; Kaiser, Ute

    2012-06-01

    This report is an extension of the study for structural imaging of 5-6 nm thick β-Si(3)N(4) [0001] crystal with a spherical aberration corrected transmission electron microscope by Zhang and Kaiser [2009. Structure imaging of β-Si(3)N(4) by spherical aberration-corrected high-resolution transmission electron microscopy. Ultramicroscopy 109, 1114-1120]. In this work, a local symmetry breaking with an uneven resolution of dumbbells in the six-membered rings revealed in the reported images in the study of Zhang and Kaiser has been analyzed in detail. It is found that this local asymmetry in the image basically is not relevant to a slight mistilt of the specimen and/or a beam tilt (coma). Rather the certain variation of the tetrahedral bond length of Si-N(4) in the crystal structure is found to be responsible for the uneven resolution with a local structural variation from region to region. This characteristic of the variation is also supposed to give a distorted lattice of apparently 2°-2.5° deviations from the perfect hexagonal unit cell as observed in the reported image in the work of Zhang and Kaiser. It is discussed that this variation may prevail only in a thin specimen with a thickness ranging ~≤ 5-6 nm. At the same time, it is noted that the average of the bond length variation is close to the fixed length known in a bulk crystal of β-Si(3)N(4).

  11. In vivo and in vitro effectiveness of Azadirachta indica-synthesized silver nanocrystals against Plasmodium berghei and Plasmodium falciparum, and their potential against malaria mosquitoes.

    Science.gov (United States)

    Murugan, Kadarkarai; Panneerselvam, Chellasamy; Samidoss, Christina Mary; Madhiyazhagan, Pari; Suresh, Udaiyan; Roni, Mathath; Chandramohan, Balamurugan; Subramaniam, Jayapal; Dinesh, Devakumar; Rajaganesh, Rajapandian; Paulpandi, Manickam; Wei, Hui; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Pavela, Roman; Canale, Angelo; Benelli, Giovanni

    2016-06-01

    Malaria transmission is a serious emergence in urban and semiurban areas worldwide, becoming a major international public health concern. Malaria is transmitted through the bites of Anopheles mosquitoes. The extensive employ of synthetic pesticides leads to negative effects on human health and the environment. Recently, plant-synthesized nanoparticles have been proposed as highly effective mosquitocides. In this research, we synthesized silver nanoparticles (AgNP) using the Azadirachta indica seed kernel extract as reducing and stabilizing agent. AgNP were characterized by UV-vis spectrophotometry, SEM, EDX, XRD and FTIR spectroscopy. The A. indica seed kernel extract was toxic against Anopheles stephensi larvae and pupae, LC50 were 232.8ppm (larva I), 260.6ppm (II), 290.3ppm (III), 323.4ppm (IV), and 348.4ppm (pupa). AgNP LC50 were 3.9ppm (I), 4.9ppm (II), 5.6ppm (III), 6.5ppm (IV), and 8.2ppm (pupa). The antiplasmodial activity of A. indica seed kernel extract and AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of A. indica seed kernel extract were 63.18μg/ml (CQ-s) and 69.24μg/ml (CQ-r). A. indica seed kernel-synthesized AgNP achieved IC50, of 82.41μg/ml (CQ-s) and 86.12μg/ml (CQ-r). However, in vivo anti-plasmodial experiments conducted on Plasmodium berghei infecting albino mice showed moderate activity of the A. indica extract and AgNP. Overall, this study showed that the A. indica-mediated fabrication of AgNP is of interest for a wide array of purposes, ranging from IPM of mosquito vectors to the development of novel and cheap antimalarial drugs.

  12. Oxidative stress and modification of renal vascular permeability are associated with acute kidney injury during P. berghei ANKA infection.

    Science.gov (United States)

    Elias, Rosa Maria; Correa-Costa, Matheus; Barreto, Claudiene Rodrigues; Silva, Reinaldo Correia; Hayashida, Caroline Y; Castoldi, Angela; Gonçalves, Giselle Martins; Braga, Tarcio Teodoro; Barboza, Renato; Rios, Francisco José; Keller, Alexandre Castro; Cenedeze, Marcos Antonio; Hyane, Meire Ioshie; D'Império-Lima, Maria Regina; Figueiredo-Neto, Antônio Martins; Reis, Marlene Antônia; Marinho, Cláudio Romero Farias; Pacheco-Silva, Alvaro; Câmara, Niels Olsen Saraiva

    2012-01-01

    Malaria associated-acute kidney injury (AKI) is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. However, the causes that lead to a framework of malaria-associated AKI are still poorly characterized. Some clinical studies speculate that oxidative stress products, a characteristic of Plasmodium infection, as well as proinflammatory response induced by the parasite are involved in its pathophysiology. Therefore, we aimed to investigate the development of malaria-associated AKI during infection by P. berghei ANKA, with special attention to the role played by the inflammatory response and the involvement of oxidative stress. For that, we took advantage of an experimental model of severe malaria that showed significant changes in the renal pathophysiology to investigate the role of malaria infection in the renal microvascular permeability and tissue injury. Therefore, BALB/c mice were infected with P. berghei ANKA. To assess renal function, creatinine, blood urea nitrogen, and ratio of proteinuria and creatininuria were evaluated. The products of oxidative stress, as well as cytokine profile were quantified in plasma and renal tissue. The change of renal microvascular permeability, tissue hypoxia and cellular apoptosis were also evaluated. Parasite infection resulted in renal dysfunction. Furthermore, we observed increased expression of adhesion molecule, proinflammatory cytokines and products of oxidative stress, associated with a decrease mRNA expression of HO-1 in kidney tissue of infected mice. The measurement of lipoprotein oxidizability also showed a significant increase in plasma of infected animals. Together, our findings support the idea that products of oxidative stress, as well as the immune response against the parasite are crucial to changes in kidney architecture and microvascular endothelial permeability of BALB/c mice infected with P. berghei ANKA.

  13. The Maternally Inheritable Wolbachia wAlbB Induces Refractoriness to Plasmodium berghei in Anopheles stephensi

    Science.gov (United States)

    Joshi, Deepak; Pan, Xiaoling; McFadden, Michael J.; Bevins, David; Liang, Xiao; Lu, Peng; Thiem, Suzanne; Xi, Zhiyong

    2017-01-01

    The endosymbiont Wolbachia wAlbB induces refractoriness to Plasmodium falciparum in Anopheles stephensi, the primary mosquito vector of human malaria in the Middle East and South Asia. However, it remains unknown whether such refractoriness can be extended to other malaria species. In particular, it was reported that under very specific conditions, wAlbB can enhance Plasmodium infection in some hosts. Here, we measured the impact of wAlbB on the rodent malaria parasite Plasmodium berghei in A. stephensi by comparing the load of oocysts and sporozoites in midguts and salivary glands, respectively, between wAlbB-infected and -uninfected mosquitoes. To investigate whether wAlbB modulated mosquito immune defense against parasites, we compared the expression of the immune genes, which were previously reported to involve in antimalarial response, in both midguts and the remaining carcass tissues of mosquitoes. The stable association of wAlbB with A. stephensi resulted in reduction of parasites by more than half at the oocyst stage, and up to 91.8% at the sporzoite stage. The anti-plasmodium immune genes, including TEP1, LRIM1, Toll pathway gene Rel1 and the effector Defensin 1, were induced by wAlbB in different mosquito body tissues. These findings suggest that immune priming is a potential cause of wAlbB-mediated antimalarial response in A. stephensi. More importantly, no evidence was found for any enhancement of Plasmodium infection in A. stephensi stably infected with wAlbB. We discuss these findings with possible implementations of Wolbachia for malaria control in disease endemic areas. PMID:28337184

  14. Mitochondrial peroxidase TPx-2 is not essential in the blood and insect stages of Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Masuda-Suganuma Hirono

    2012-11-01

    Full Text Available Abstract Background Malaria parasites actively proliferate in the body of their vertebrate and insect hosts, and are subjected to the toxic effects of reactive oxygen species. The antioxidant defenses of malaria parasites are considered to play essential roles in their survival and are thus considered promising targets for intervention. We sought to identify the cellular function of thioredoxin peroxidase-2 (TPx-2, which is expressed in the mitochondria, by disrupting the TPx-2 gene (pbtpx-2 of the rodent malaria parasite Plasmodium berghei. Findings In three independent experiments, two disruptant populations (TPx-2 KO and three wild-type parasite populations with pyrimethamine resistance (dhfr-ts/mt at the DHFR-TS locus and intact pbtpx-2 (TPx-2 WT were obtained and cloned. Null expression of TPx-2 in the KO population was confirmed by RT-PCR and Western blot analyses. The TPx-2 KO parasite developed normally in mouse erythrocytes and multiplied at a rate similar to that of the TPx-2 WT parasite during the experimental period. The peak period of gametocytemia was delayed by 1 day in the TPx-2 KO compared with that of the TPx-2 WT and the parent parasite, however, the highest gametocyte number was comparable. The number of midgut oocysts in the TPx-2 KO at 14 days post feeding was comparable to that of the TPx-2 WT. Conclusions The present finding suggests that mitochondrial Prx TPx-2 is not essential for asexual and the insect stage development of the malaria parasite.

  15. Enhanced depletion of glutathione and increased liver oxidative damage in aflatoxin-fed mice infected with Plasmodium berghei

    DEFF Research Database (Denmark)

    Ankrah, N A; Sittie, A; Addo, P G;

    1995-01-01

    The effect of dietary aflatoxins B1 and G1 and Plasmodium berghei infection on glutathione (GSH) levels and liver status in mice was investigated. Three days after intraperitoneal injection of 0.1 x 10(6) parasitized red blood cells into the mice, there was a significant fall in blood glutathione...... levels accompanied by a significant increase in serum cholinesterase and liver malonic dialdehyde levels in the mice fed aflatoxin compared with those in the control group. The results suggested that malaria parasites can enhance depletion of host glutathione and oxidative damage of the liver in mice fed...... low levels of aflatoxins....

  16. miR-132/212 knockout mice reveal roles for these miRNAs in regulating cortical synaptic transmission and plasticity.

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    Judit Remenyi

    Full Text Available miR-132 and miR-212 are two closely related miRNAs encoded in the same intron of a small non-coding gene, which have been suggested to play roles in both immune and neuronal function. We describe here the generation and initial characterisation of a miR-132/212 double knockout mouse. These mice were viable and fertile with no overt adverse phenotype. Analysis of innate immune responses, including TLR-induced cytokine production and IFNβ induction in response to viral infection of primary fibroblasts did not reveal any phenotype in the knockouts. In contrast, the loss of miR-132 and miR-212, while not overtly affecting neuronal morphology, did affect synaptic function. In both hippocampal and neocortical slices miR-132/212 knockout reduced basal synaptic transmission, without affecting paired-pulse facilitation. Hippocampal long-term potentiation (LTP induced by tetanic stimulation was not affected by miR-132/212 deletion, whilst theta burst LTP was enhanced. In contrast, neocortical theta burst-induced LTP was inhibited by loss of miR-132/212. Together these results indicate that miR-132 and/or miR-212 play a significant role in synaptic function, possibly by regulating the number of postsynaptic AMPA receptors under basal conditions and during activity-dependent synaptic plasticity.

  17. Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs.

    Science.gov (United States)

    Cappuccio, Javier A; Pena, Lindomar; Dibárbora, Marina; Rimondi, Agustina; Piñeyro, Pablo; Insarralde, Lucas; Quiroga, María A; Machuca, Mariana; Craig, Maria I; Olivera, Valeria; Chockalingam, Ashok; Perfumo, Carlos J; Perez, Daniel R; Pereda, Ariel

    2011-12-01

    Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The current study describes the clinical epidemiology, pathology, and molecular and biological characteristics of the virus. Phylogenetic analysis revealed that the virus isolate shared nucleotide identities of 96-98 % with H3N2 IAVs that circulated in humans from 2000 to 2003. Antigenically, sera from experimentally inoculated animals cross-reacted mainly with non-contemporary human-origin H3N2 influenza viruses. In an experimental infection in a commercial swine breed, the virus was of low virulence but was transmitted efficiently to contact pigs and caused severe disease when an infected animal acquired a secondary bacterial infection. This is the first report of a wholly human H3N2 IAV associated with clinical disease in pigs in South America. These studies highlight the importance of two-way transmission of IAVs and SIVs between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide.

  18. The systematic functional analysis of plasmodium protein kinases identifies essential regulators of mosquito transmission

    KAUST Repository

    Tewari, Rita

    2010-10-21

    Although eukaryotic protein kinases (ePKs) contribute to many cellular processes, only three Plasmodium falciparum ePKs have thus far been identified as essential for parasite asexual blood stage development. To identify pathways essential for parasite transmission between their mammalian host and mosquito vector, we undertook a systematic functional analysis of ePKs in the genetically tractable rodent parasite Plasmodium berghei. Modeling domain signatures of conventional ePKs identified 66 putative Plasmodium ePKs. Kinomes are highly conserved between Plasmodium species. Using reverse genetics, we show that 23 ePKs are redundant for asexual erythrocytic parasite development in mice. Phenotyping mutants at four life cycle stages in Anopheles stephensi mosquitoes revealed functional clusters of kinases required for sexual development and sporogony. Roles for a putative SR protein kinase (SRPK) in microgamete formation, a conserved regulator of clathrin uncoating (GAK) in ookinete formation, and a likely regulator of energy metabolism (SNF1/KIN) in sporozoite development were identified. 2010 Elsevier Inc.

  19. Antiplasmodial effects of the aqueous ethanolic seed extract of Ziziphus mauritiana against Plasmodium berghei in Swiss albino mice

    Directory of Open Access Journals (Sweden)

    Tulika Mishra

    2014-08-01

    Full Text Available Ziziphus mauritiana is a fruit tree used traditionally since long back for wound healing, immunepotentiator, asthma, sedative, stomachic, styptic, as tonic etc. The present study determines the antiplasmodial effect of aqueous ethanolic seed extract against Chloroquine sensitive Plasmodium berghei berghei nk65 infection in Swiss albino mice. Based upon the acute toxicity data three different doses (100, 200, 400 mg/kg body weight of the plant extract was chosen to study the blood schizonticidal activity in early infection and in established infection and was compared with chloroquine. The Prophylactic activity was also assessed and compared with pyrimethamine. No mortality was observed in acute toxicity study however, above the dose of 1000 mg/kg animals showed the lethargic behaviour. In early infection, and in established infection the doses (100-400 mg/kg b.wt was found to cause significant (P<0.001 suppression of infection in a dose dependent manner as compared to control. Although, the activity was lower than standard chloroquine. Similarly, the extract at all the doses caused the suppression in repository activity but was lower than pyrimethamine. The mean survival time was also increased in mice by 14 and 17 days at the doses of 200 and 400 mg/kg respectively, whereas the control group sustained only for 7 days. Thus, the seed extract showed the effectiveness against plasmodium infection.

  20. Gonadal Steroids Negatively Modulate Oxidative Stress in CBA/Ca Female Mice Infected with P. berghei ANKA

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    Néstor Aarón Mosqueda-Romo

    2014-01-01

    Full Text Available We decreased the level of gonadal steroids in female and male mice by gonadectomy. We infected these mice with P. berghei ANKA and observed the subsequent impact on the oxidative stress response. Intact females developed lower levels of parasitaemia and lost weight faster than intact males. Gonadectomised female mice displayed increased levels of parasitaemia, increased body mass, and increased anaemia compared with their male counterparts. In addition, gonadectomised females exhibited lower specific catalase, superoxide dismutase, and glutathione peroxidase activities in their blood and spleen tissues compared with gonadectomised males. To further study the oxidative stress response in P. berghei ANKA-infected gonadectomised mice, nitric oxide levels were assessed in the blood and spleen, and MDA levels were assessed in the spleen. Intact, sham-operated, and gonadectomised female mice exhibited higher levels of nitric oxide in the blood and spleen compared with male mice. MDA levels were higher in all of the female groups. Finally, gonadectomy significantly increased the oxidative stress levels in females but not in males. These data suggest that differential oxidative stress is influenced by oestrogens that may contribute to sexual dimorphism in malaria.

  1. In vivo antiplasmodial activity of extract and fractions of Trema orientalis in P. berghei-induced malaria in mice

    Institute of Scientific and Technical Information of China (English)

    Oludele Olanlokun; Moses David; Tolulope Ilori; Victoria Abe

    2016-01-01

    Objective:To assess the in vivo antimalarial potential of various solvent extracts and fractions of Trema orientalis. Methods: In this study, the animal model of antimalarial activity was employed using Plasmodium berghei-induced mice. The crude methanol extract was fractionated using vacuum liquid chromatography in the order of increasing polarity using dichloromethane, ethylacetate and methanol. Percentages of parasitemia and clearance were used as indices for antiplasmodial activities. The full blood count was also assayed while the gas chromatography-mass spectrometer analysis of the most potent fraction was carried out to detect the active compounds presenting in it. Results:Dichloromethane fraction had the least percentage of parasitemia [(0.19 ± 0.07)%] and the highest percentage of clearance [(91.74 ± 8.38)%] at the highest dose used (200 mg/kg body weight) after day 7 relative to the artemisinin control which cleared the parasite after day 3. The ethylacetate fraction showed the least percentage of clearance [(70.52 ± 5.64)%] at the highest dose used (200 mg/kg body weight) after day 7. Conclusions:The results obtained showed that purification enhanced the antiplasmodial activity of Trema orientalis in Plasmodium berghei-induced malaria in mice. The antiplasmodial activity of the dichloromethane is a strong indication that the fraction, if purified further, may contain drug candidates for the treatment of malaria in the nearest future.

  2. Time-measured phylogenies of gag, pol and env sequence data reveal the direction and time interval of HIV-1 transmission

    NARCIS (Netherlands)

    Rachinger, Andrea; Groeneveld, Paul H. P.; van Assen, Sander; Lemey, Philippe; Schuitemaker, Hanneke

    2011-01-01

    Objective: To investigate whether time-measured phylogenetic analysis of longitudinal viral sequences can establish the direction and timing of HIV-1 transmission in an epidemiologically linked transmission cluster of three homosexual men. Design: An HIV-1-infected homosexual man (patient 1) and his

  3. Curcumin-arteether combination therapy of Plasmodium berghei-infected mice prevents recrudescence through immunomodulation.

    Directory of Open Access Journals (Sweden)

    Palakkod G Vathsala

    Full Text Available Earlier studies in this laboratory have shown the potential of artemisinin-curcumin combination therapy in experimental malaria. In a parasite recrudescence model in mice infected with Plasmodium berghei (ANKA, a single dose of alpha,beta-arteether (ART with three oral doses of curcumin prevented recrudescence, providing almost 95% protection. The parasites were completely cleared in blood with ART-alone (AE or ART+curcumin (AC treatments in the short-term, although the clearance was faster in the latter case involving increased ROS generation. But, parasites in liver and spleen were not cleared in AE or AC treatments, perhaps, serving as a reservoir for recrudescence. Parasitemia in blood reached up to 60% in AE-treated mice during the recrudescence phase, leading to death of animals. A transient increase of up to 2-3% parasitemia was observed in AC-treatment, leading to protection and reversal of splenomegaly. A striking increase in spleen mRNA levels for TLR2, IL-10 and IgG-subclass antibodies but a decrease in those for INFγ and IL-12 was observed in AC-treatment. There was a striking increase in IL-10 and IgG subclass antibody levels but a decrease in INFγ levels in sera leading to protection against recrudescence. AC-treatment failed to protect against recrudescence in TLR2(-/- and IL-10(-/- animals. IL-10 injection to AE-treated wild type mice and AC-treated TLR2(-/- mice was able to prolong survival. Blood from the recrudescence phase in AE-treatment, but not from AC-treatment, was able to reinfect and kill naïve animals. Sera from the recrudescence phase of AC-treated animals reacted with several parasite proteins compared to that from AE-treated animals. It is proposed that activation of TLR2-mediated innate immune response leading to enhanced IL-10 production and generation of anti-parasite antibodies contribute to protective immunity in AC-treated mice. These results indicate a potential for curcumin-based combination therapy to

  4. Different patterns of synaptic transmission revealed between hippocampal CA3 stratum oriens and stratum lucidum interneurons and their pyramidal cell targets.

    Science.gov (United States)

    Aaron, G B; Wilcox, K S; Dichter, M A

    2003-01-01

    Stratum lucidum (SL) interneurons likely mediate feedforward inhibition between the dentate gyrus mossy fibers and CA3 pyramidal cells, while stratum oriens (SO) interneurons likely provide both feedforward and feedback inhibition within the CA3 commissural/associational network. Using dual whole-cell patch-clamp recordings between interneurons and CA3 pyramidal cells, we have examined SL and SO interneurons and their synapses within organotypic hippocampal slice cultures. Biocytin staining revealed different morphologies between these interneuron groups, both being very similar to those found previously in acute slices. The kinetics of IPSCs were similar between the two groups, but the reliability of synaptic transmission of SL interneuron (SL-INT) IPSCs was significantly lower than the virtually 100% reliability (non-existent failure rates) of SO-INT IPSCs. The SL-INT IPSCs also had a lower quantal content than the SO-INT IPSCs. In addition, SL-INTs were less likely than SO-INTs to innervate or to be innervated by nearby CA3 pyramidal cells. Paired-pulse stimulation at 100 ms interstimulus intervals produced similar paired-pulse depression in both interneuron synapses, despite the significantly higher failure rate of IPSCs produced by the SL-INTs compared with SO-INTs. CV analysis supported the hypothesis that paired-pulse depression was presynaptic. During repetitive, high frequency stimulation (>10 Hz for 500 ms) the two different synapses exhibited distinctly different forms of short-term plasticity: all SL interneurons displayed significant short-term facilitation (mean 113% facilitation, n=4), while, by contrast, SO interneuron synapses displayed either short-term depression (mean 42% depression, n=5 of 8) or no net facilitation or depression (n=3 of 8). These results indicate that the synaptic properties of interneurons can be quite different for interneurons in different hippocampal circuits.

  5. A Year of Infection in the Intensive Care Unit: Prospective Whole Genome Sequencing of Bacterial Clinical Isolates Reveals Cryptic Transmissions and Novel Microbiota.

    Science.gov (United States)

    Roach, David J; Burton, Joshua N; Lee, Choli; Stackhouse, Bethany; Butler-Wu, Susan M; Cookson, Brad T; Shendure, Jay; Salipante, Stephen J

    2015-07-01

    Bacterial whole genome sequencing holds promise as a disruptive technology in clinical microbiology, but it has not yet been applied systematically or comprehensively within a clinical context. Here, over the course of one year, we performed prospective collection and whole genome sequencing of nearly all bacterial isolates obtained from a tertiary care hospital's intensive care units (ICUs). This unbiased collection of 1,229 bacterial genomes from 391 patients enables detailed exploration of several features of clinical pathogens. A sizable fraction of isolates identified as clinically relevant corresponded to previously undescribed species: 12% of isolates assigned a species-level classification by conventional methods actually qualified as distinct, novel genomospecies on the basis of genomic similarity. Pan-genome analysis of the most frequently encountered pathogens in the collection revealed substantial variation in pan-genome size (1,420 to 20,432 genes) and the rate of gene discovery (1 to 152 genes per isolate sequenced). Surprisingly, although potential nosocomial transmission of actively surveilled pathogens was rare, 8.7% of isolates belonged to genomically related clonal lineages that were present among multiple patients, usually with overlapping hospital admissions, and were associated with clinically significant infection in 62% of patients from which they were recovered. Multi-patient clonal lineages were particularly evident in the neonatal care unit, where seven separate Staphylococcus epidermidis clonal lineages were identified, including one lineage associated with bacteremia in 5/9 neonates. Our study highlights key differences in the information made available by conventional microbiological practices versus whole genome sequencing, and motivates the further integration of microbial genome sequencing into routine clinical care.

  6. Studies on the effects of sida acuta and vetiveria zizanioides against the malarial vector, anopheles stephensi and malarial parasite, plasmodium berghei

    Science.gov (United States)

    Methanolic extracts of Sida acuta and Vetiveria zizanioides leaves and root were studied for toxicity to Anopheles stephensi mosquitoes and to the malaria parasite Plasmodium berghei in mice. The extracts reduced parasitemia levels in mice by 17-69%, depending on extract concentration. Median le...

  7. Development of a transgenic Plasmodium berghei line (Pb pfpkg expressing the P. falciparum cGMP-dependent protein kinase, a novel antimalarial drug target.

    Directory of Open Access Journals (Sweden)

    Rita Tewari

    Full Text Available With the inevitable selection of resistance to antimalarial drugs in treated populations, there is a need for new medicines to enter the clinic and new targets to progress through the drug discovery pipeline. In this study we set out to develop a transgenic rodent model for testing inhibitors of the Plasmodium falciparum cyclic GMP-dependent kinase in vivo. A model was needed that would allow us to investigate whether differences in amino acid sequence of this enzyme between species influences in vivo efficacy. Here we report the successful development of a transgenic P. berghei line in which the cyclic GMP-dependent protein kinase (PKG was replaced by the P. falciparum orthologue. We demonstrate that the P. falciparum orthologue was able to functionally complement the endogenous P. berghei pkg gene throughout blood stage development and early sexual development. However, subsequent development in the mosquito was severely compromised. We show that this is due to a defect in the female lineage of the transgenic by using genetic crosses with both male and female deficient P. berghei lines. This defect could be due to expression of a female-specific target in the mosquito stages of P. berghei that cannot be phosphorylated by the P. falciparum kinase. Using a previously reported anti-coccidial inhibitor of the cyclic GMP-dependent protein kinase, we show no difference in in vivo efficacy between the transgenic and control P. berghei lines. This in vivo model will be useful for screening future generations of cyclic GMP-dependent protein kinase inhibitors and allowing us to overcome any species-specific differences in the enzyme primary sequence that would influence in vivo efficacy in the rodent model. The approach will also be applicable to in vivo testing of other antimalarial compounds where the target is known.

  8. Development of a transgenic Plasmodium berghei line (Pb pfpkg) expressing the P. falciparum cGMP-dependent protein kinase, a novel antimalarial drug target.

    Science.gov (United States)

    Tewari, Rita; Patzewitz, Eva-Maria; Poulin, Benoit; Stewart, Lindsay; Baker, David A

    2014-01-01

    With the inevitable selection of resistance to antimalarial drugs in treated populations, there is a need for new medicines to enter the clinic and new targets to progress through the drug discovery pipeline. In this study we set out to develop a transgenic rodent model for testing inhibitors of the Plasmodium falciparum cyclic GMP-dependent kinase in vivo. A model was needed that would allow us to investigate whether differences in amino acid sequence of this enzyme between species influences in vivo efficacy. Here we report the successful development of a transgenic P. berghei line in which the cyclic GMP-dependent protein kinase (PKG) was replaced by the P. falciparum orthologue. We demonstrate that the P. falciparum orthologue was able to functionally complement the endogenous P. berghei pkg gene throughout blood stage development and early sexual development. However, subsequent development in the mosquito was severely compromised. We show that this is due to a defect in the female lineage of the transgenic by using genetic crosses with both male and female deficient P. berghei lines. This defect could be due to expression of a female-specific target in the mosquito stages of P. berghei that cannot be phosphorylated by the P. falciparum kinase. Using a previously reported anti-coccidial inhibitor of the cyclic GMP-dependent protein kinase, we show no difference in in vivo efficacy between the transgenic and control P. berghei lines. This in vivo model will be useful for screening future generations of cyclic GMP-dependent protein kinase inhibitors and allowing us to overcome any species-specific differences in the enzyme primary sequence that would influence in vivo efficacy in the rodent model. The approach will also be applicable to in vivo testing of other antimalarial compounds where the target is known.

  9. Plasmodium berghei ANKA: erythropoietin activates neural stem cells in an experimental cerebral malaria model

    DEFF Research Database (Denmark)

    Core, Andrew; Hempel, Casper; Kurtzhals, Jørgen A L;

    2011-01-01

    Cerebral malaria (CM) causes substantial mortality and neurological sequelae in survivors, and no neuroprotective regimens are currently available for this condition. Erythropoietin (EPO) reduces neuropathology and improves survival in murine CM. Using the Plasmodium berghei model of CM, we...... investigated if EPO's neuroprotective effects include activation of endogenous neural stem cells (NSC). By using immunohistochemical markers of different NSC maturation stages, we show that EPO increased the number of nestin(+) cells in the dentate gyrus and in the sub-ventricular zone of the lateral...... ventricles, relative to control-treatment. 75% of the EPO-treated CM mice displayed migration as nestin(+) NSC. The NSC showed differentiation towards a neural cell lineage as shown by PSA-NCAM binding and NSC maturation and lineage commitment was significantly affected by exogenous EPO and by CM in the sub...

  10. Rate of red blood cell destruction varies in different strains of mice infected with Plasmodium berghei-ANKA after chronic exposure

    Directory of Open Access Journals (Sweden)

    Kikuchi Mihoko

    2009-05-01

    Full Text Available Abstract Background Severe malaria anaemia in the semi-immune individuals in the holo-endemic area has been observed to occur at low parasite density with individual variation in the responses. Thus the following has been thought to be involved: auto-immune-mediated mechanisms of uninfected red blood cell destruction, and host genetic factors to explain the differences in individual responses under the same malaria transmission. In this study, the extent of red blood cell (RBC destruction in different strains of semi-immune mice model at relatively low parasitaemia was studied. Methodology To generate semi-immunity, four strains of mice were taken through several cycles of infection and treatment. By means of immunofluorescent assay and ELISA, sera were screened for anti-erythrocyte auto-antibodies, and their relationship with haematological parameters and parasitaemia in the strains of semi-immune mice was investigated. Results Upon challenge with Plasmodium berghei ANKA after generating semi-immune status, different mean percentage haemoglobin (Hb drop was observed in the mice strains (Balb/c = 47.1%; NZW = 30.05%; C57BL/6 = 28.44%; CBA = 25.1%, which occurred on different days for each strain (for Balb/c, mean period = 13.6 days; for C57BL/6, NZW, and CBA mean period = 10.6, 10.8, 10.9 days respectively. Binding of antibody to white ghost RBCs was observed in sera of the four strains of semi-immune mice by immunofluorescence. Mean percentage Hb drop per parasitaemia was highest in Balb/c (73.6, followed by C57BL/6 (8.6, CBA (6.9 and NZW (4.0, p = 0.0005. Consequently, auto-antibodies level to ghost RBC were correlated with degree of anaemia and were highest in Balb/c, when compared with the other strains, p Conclusion The results presented in this study seem to indicate that anti-RBC auto-antibodies may be involved in the destruction of uninfected RBC in semi-immune mice at relatively low parasite burden. Host genetic factors may also

  11. Effects of the methanolic seeds extract of Carica Papaya on plasmodium Berghei infected mice

    Institute of Scientific and Technical Information of China (English)

    Amazu LU; Ebong OO; Azikiwe CCA; Unekwe PC; Siminialayi MI; Nwosu PJC; Ezeani MC; Obidiya OS; Ajugwo AO

    2009-01-01

    into 5subgroups (a-e)of 5animals per group.At the appropriate time,50 mg/kg/day,1 00 mg/kg/day and 200 mg/kg/day of crude extract of C.papaya were administered orally to the different subgroups(b-d)within the three main groups.One subgroup(a)in each main group also received orally,5 mg/kg/day of chloroquine phosphate as positive control while one subgroup (e)in each main group also received orally,0.2 mL /kg/day of distilled water as negative control.Malaria parasites infected red blood cells numbering 1 ×1 07 and suspended in 0.2 mL of physiological saline was inoc-ulated intraperitoneally,to each animal of the subgroups (a-d)in each of the three main groups at the appro-priate time.Blood smears were made from animals'tail,stained with Lieshman and examined microscopically at 100 ×for the presence of malaria parasite.Percentage malaria parastaemia was calculated as well as average percentage malaria parasitaemia suppression.Results:Extraction yield of 25.29% was obtained while the LD50 was 620 mg/kg.The phytochemistry showed the richly presence of alkaloids,as well as glycosides,car-bohydrates,resins,fats and fixed oils.The suppressive study at doses of 200,100 and 50mg/kg/day showed 53.02%,43.43% and 19.83 % suppressive activity against Plasmodium berghei respectively.This activity compared to that of chloroquine,a standard antimalaria drug that gave 95.95% suppressive anti-parasitaemia. The prophylactic study at doses of 200,100 and 50 mg/kg/day showed 63.85%,61.12% and 48.08% pre-vention to malaria parasitaemia respectively as against 94.78% showed by chloroquine.The curative study however,at doses of 200,100 and 50 mg/kg/day failed to suppress malaria parasitaemia with a mean survival range of 6-8days as against 27.2 days showed by chloroquine.The seeds extract of C.papaya showed a signifi-cant malaria parasitaemia suppressive activity (P≤0.05).These activities are dose dependent and compara-ble to those of Chloroquine phosphate.Conclusion:The results above

  12. Protection of athymic (Nu/Nu BALB/c mice against Plasmodium berghei by splenocytes from normal (Nu/ + BALB/c mice

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    José J. Ferraroni

    1985-12-01

    Full Text Available Athymic BALB/c (Nu/Nu mice died at 7-13 days after inoculation (DAI of Plasmodium berghei NK65, whereas their heterozygous (Nu/+ littermates died at 7-8 DAI. Nude (Nu/Nu mice, reconstituted with 2 x 10(7 splenocytes from uninfected heterozygous (Nu/+ littermates at 20 days before parasite inoculation (DBI, died about 2 days earlier than control nude mice; nude mice reconstituted at 10 or 2 DBI lived 2 to 4 days longer than control nudes; and nude mice reconstituted 2 DAI lived even longer and some survived. These findings indicate that P. berghei NK65 induces at least two T-cell dependent immune phenomena, one suppressive and the other stimulatory. Reconstitution of nude mice with T-cells from BALB/c (Nu/+ mice appeared to reduce or bypass suppressive T-cell activities which allowed the formation of a protective immune response by some of the nude mice.

  13. Evidência da ação antiparasitária da azitromicina na infecção experimental de camundongos pelo Plasmodium berghei

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    Gakiya Erika

    2001-01-01

    Full Text Available A azitromicina debelou a infecção experimental de camundongos pelo Plasmodium berghei quando administrada, pela via oral e durante 28 dias, na dose de 100mg/kg, iniciada no mesmo dia em que os animais foram infectados. Mediante uso de 10mg/kg houve insucesso. Os resultados obtidos suscitam investigações complementares sobre a referida atividade antiparasitária desse medicamento.

  14. Further antiplasmodial effects of the aqueous extract of cym-bopogon citratus stapf (lemon grass) against plasmodium berghei in Swiss albino mice

    Institute of Scientific and Technical Information of China (English)

    DV Dapper; IMSiminialayi; OO Ebong

    2008-01-01

    Lemon grass (Cymbopogon citratus Stapf)is a popular alternative to western medicines for a number of condi-tions,including fevers,muscle soreness and superficial infections in Nigeria.In addition to its already reported suppressive effects against P.berghei infection,this study sought to determine its repository and blood schizon-ticidal activities in established P.berghei infection using Swiss albino mice as models.Mice weighing on aver-age,between 15 and 25g were given 103mg/kg,155mg/kg and 310mg/kg/day of the crude aqueous extract of cymbopogon citratus stapf,in the 4-day test,24-hour Rane test and 72-hour Rane test.The effects of these do-ses of the extract were then compared with chloroquine (5mg/kg/day)and sulphadoxine /pyrimethamine (3mg/kg/day).We report an average percentage suppressive repository activity of 65.8% for the extract at a dose of 310mg/kg and a blood schizonticidal activity that increased from 68.33% in the 24-hour Rane test to 92% in the 72-hour Rane test for the same dose of extract.The crude aqueous extract of C.citratus stapf thus has significant repository and blood schizonticidal activities against established P.berghei infection in Swiss al-bino mice compare to that of pyrimethamine and sulphadoxine /pyrimethamine respectively.

  15. Unlike the synchronous Plasmodium falciparum and P. chabaudi infection, the P. berghei and P. yoelii asynchronous infections are not affected by melatonin

    Directory of Open Access Journals (Sweden)

    Piero Bagnaresi

    2009-04-01

    Full Text Available Piero Bagnaresi1, Eduardo Alves1, Henrique Borges da Silva1, Sabrina Epiphanio2, Maria M Mota2, Célia RS Garcia11Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil; 2Unidade de Malária, Instituto de Medicina Molecular, Universidade de Lisboa, Lisboa, PortugalAbstract: We have previously reported that Plasmodium chabaudi and P. falciparum sense the hormone melatonin and this could be responsible for the synchrony of malaria infection. In P. chabaudi and P. falciparum, melatonin induces calcium release from internal stores, and this response is abolished by U73122, a phospholipase C inhibitor, and luzindole, a melatoninreceptor competitive antagonist. Here we show that, in vitro, melatonin is not able to modulate cell cycle, nor to elicit an elevation in intracellular calcium concentration of the intraerythrocytic forms of P. berghei or P. yoelii, two rodent parasites that show an asynchrononous development in vivo. Interestingly, melatonin and its receptor do not seem to play a role during hepatic infection by P. berghei sporozoites either. These data strengthen the hypothesis that hostderived melatonin does not synchronize malaria infection caused by P. berghei and P. yoelii. Moreover, these data explain why infections by these parasites are asynchronous, contrary to what is observed in P. falciparum and P. chabaudi infections.Keywords: malaria, calcium, melatonin, cell cycle, rhythm, sporozoite

  16. Early infection dynamics after experimental challenge with Mycobacterium avium subspecies paratuberculosis in calves reveal limited calf-to-calf transmission and no impact of Hsp70 vaccination.

    Science.gov (United States)

    Santema, Wiebren J; Poot, Jacqueline; Segers, Ruud P A M; Van den Hoff, Daniëlle J P; Rutten, Victor P M G; Koets, Ad P

    2012-11-19

    Efficient control of bovine paratuberculosis is hampered by lack of a vaccine. The purpose of this study was to evaluate efficacy of a candidate vaccine, consisting of recombinant Mycobacterium avium subspecies paratuberculosis (MAP) Hsp70 with DDA adjuvant, in calves experimentally infected with MAP. Four groups of 14 animals each were used. Animals in group 1 and 2 were all vaccinated with Hsp70/DDA at day 0, 84, 168 and 357, and those in group 3 and 4 were non-vaccinated controls. In each group half (n=7) of the animals were challenged and the remaining half served as contacts. Blood and fecal samples were collected at three week intervals until day 588, and subsequently all animals were subjected to necropsy. The primary outcomes assessed were fecal culture (FC) of MAP, tissue colonization of MAP, and transmission of infection to contact animals. The kinetics of MAP shedding in feces of challenged animals showed a peak around 130 days post-challenge, irrespective of vaccination status. At necropsy no differences in the level of tissue colonization between vaccinated animals and controls were observed in the challenged groups. Only one contact animal (non-vaccinated) was positive at necropsy, indicating limited to no transmission within groups. These findings indicate that Hsp70/DDA vaccination does not influence early infection dynamics after experimental infection. However, early shedding of MAP in calves did not result in efficient transmission of infection to contact animals. The latter implies that introduction of an infected calf in a cohort of susceptibles has limited consequences for spread of infection.

  17. Effect of N-Acetyl Cysteine administration to the degree of parasitemia and plasma interleukin-12 level of mice infected with plasmodium berghei and treated with artemisinin

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    Loeki E. Fitri

    2009-03-01

    Full Text Available Introduction Protection against malaria requires a cell-mediated immune response which is initiated by releasing interleukin-12 (IL-12 from antigen presenting cells (APC. N-Acetyl Cysteine (NAC is a precursor of glutathione, while glutathione itself increases IL-12 production. Treatment with NAC combined with artemisinin is supposed to increase cellular immunity of mice during Plasmodium berghei infection. The aim of this study was to measure the effects of NAC administration on the degree of parasitemia and plasma IL-12 level in mice infected with P. berghei and treated with artemisinin.Methods The research was done using post-test-control-only design using 5 groups: group A (negative control group, group B (positive control group, or mice infected with P.berghei without therapy, group C ( mice infected by P.berghei and received artemisinin 0.04 mg/g BW for 7 days, group D (mice infected with P.berghei and received artemisinin in combination with NAC 1 mg/g BW for 7 days and group E (mice infected wirth P.berghei and received artemisinin in  combination with NAC 1 mg/g BW for 3 days and tapered into ½ mg/g BW for 4 days. Parasitemia was followed up every two days. Approximately six days post infection or when the degree of parasitemia reached ± 10% therapy was begun. On the 3rd, 5th, and 7th days post therapy, mice from each group were terminated and assayed for plasma IL-12 level (ELISA, Bender Medsystems GmbH, Vienna, cat. BMS6004.Results All mice treated with artemisinin mono-therapy and combined therapy had significantly decreased parasitemia (P=0.000. There was no significant difference (P>0.05 in decreasing parasitemia among treatment groups. The plasma IL-12 level increased significantly in both groups that received the combination of artemisinin and NAC constant dose and tapering dose compared with the group that received artemisinin mono-therapy (p < 0,05. Plasma IL-12p70 level in the combination of artemisinin and NAC tapering dose

  18. Revealing the synergetic effects in Ni nanoparticle-carbon nanotube hybrids by scanning transmission X-ray microscopy and their application in the hydrolysis of ammonia borane

    Science.gov (United States)

    Zhao, Guanqi; Zhong, Jun; Wang, Jian; Sham, Tsun-Kong; Sun, Xuhui; Lee, Shuit-Tong

    2015-05-01

    The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications.The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications. Electronic supplementary information (ESI) available: Magnified TEM images, high resolution TEM images and the particle size distributions of the samples, the STXM results of a thick tube at different positions, XPS results, stability test. See DOI: 10.1039/c5nr01168j

  19. Optogenetic stimulation of VTA dopamine neurons reveals that tonic but not phasic patterns of dopamine transmission reduce ethanol self-administration

    Directory of Open Access Journals (Sweden)

    Caroline E Bass

    2013-11-01

    Full Text Available There is compelling evidence that acute ethanol exposure stimulates ventral tegmental area (VTA dopamine cell activity and that VTA-dependent dopamine release in terminal fields within the nucleus accumbens plays an integral role in the regulation of ethanol drinking behaviors. Unfortunately, due to technical limitations, the specific temporal dynamics linking VTA dopamine cell activation and ethanol self-administration are not known. In fact, establishing a causal link between specific patterns of dopamine transmission and ethanol drinking behaviors has proven elusive. Here, we sought to address these gaps in our knowledge using a newly developed viral-mediated gene delivery strategy to selectively express Channelrhodopsin-2 (ChR2 on dopamine cells in the VTA of wild-type rats. We then used this approach to precisely control VTA dopamine transmission during voluntary ethanol drinking sessions. The results confirmed that ChR2 was selectively expressed on VTA dopamine cells and delivery of blue light pulses to the VTA induced dopamine release in accumbal terminal fields with very high temporal and spatial precision. Brief high frequency VTA stimulation induced phasic patterns of dopamine release in the nucleus accumbens. Lower frequency stimulation, applied for longer periods mimicked tonic increases in accumbal dopamine. Notably, using this optogenetic approach in rats engaged in an intermittent ethanol drinking procedure, we found that tonic, but not phasic, stimulation of VTA dopamine cells selectively attenuated ethanol drinking behaviors. Collectively, these data demonstrate the effectiveness of a novel viral targeting strategy that can be used to restrict opsin expression to dopamine cells in standard outbred animals and provide the first causal evidence demonstrating that tonic activation of VTA dopamine neurons selectively decreases ethanol self-administration behaviors.

  20. Optogenetic stimulation of VTA dopamine neurons reveals that tonic but not phasic patterns of dopamine transmission reduce ethanol self-administration.

    Science.gov (United States)

    Bass, Caroline E; Grinevich, Valentina P; Gioia, Dominic; Day-Brown, Jonathan D; Bonin, Keith D; Stuber, Garret D; Weiner, Jeff L; Budygin, Evgeny A

    2013-01-01

    There is compelling evidence that acute ethanol exposure stimulates ventral tegmental area (VTA) dopamine cell activity and that VTA-dependent dopamine release in terminal fields within the nucleus accumbens plays an integral role in the regulation of ethanol drinking behaviors. Unfortunately, due to technical limitations, the specific temporal dynamics linking VTA dopamine cell activation and ethanol self-administration are not known. In fact, establishing a causal link between specific patterns of dopamine transmission and ethanol drinking behaviors has proven elusive. Here, we sought to address these gaps in our knowledge using a newly developed viral-mediated gene delivery strategy to selectively express Channelrhodopsin-2 (ChR2) on dopamine cells in the VTA of wild-type rats. We then used this approach to precisely control VTA dopamine transmission during voluntary ethanol drinking sessions. The results confirmed that ChR2 was selectively expressed on VTA dopamine cells and delivery of blue light pulses to the VTA induced dopamine release in accumbal terminal fields with very high temporal and spatial precision. Brief high frequency VTA stimulation induced phasic patterns of dopamine release in the nucleus accumbens. Lower frequency stimulation, applied for longer periods mimicked tonic increases in accumbal dopamine. Notably, using this optogenetic approach in rats engaged in an intermittent ethanol drinking procedure, we found that tonic, but not phasic, stimulation of VTA dopamine cells selectively attenuated ethanol drinking behaviors. Collectively, these data demonstrate the effectiveness of a novel viral targeting strategy that can be used to restrict opsin expression to dopamine cells in standard outbred animals and provide the first causal evidence demonstrating that tonic activation of VTA dopamine neurons selectively decreases ethanol self-administration behaviors.

  1. Protective Effect of Aqueous Crude Extract of Neem (Azadirachta indica) Leaves on Plasmodium berghei-Induced Renal Damage in Mice.

    Science.gov (United States)

    Somsak, Voravuth; Chachiyo, Sukanya; Jaihan, Ubonwan; Nakinchat, Somrudee

    2015-01-01

    Malaria is a major public health problem in the world because it can cause of death in patients. Malaria-associated renal injury is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. Therefore, new plant extracts to protect against renal injury induced by malaria infection are urgently needed. In this study, we investigated the protective effect of aqueous crude extract of Azadirachta indica (neem) leaves on renal injury induced by Plasmodium berghei ANKA infection in mice. ICR mice were injected intraperitoneally with 1 × 10(7) parasitized erythrocytes of PbANKA, and neem extracts (500, 1,000, and 2,000 mg/kg) were given orally for 4 consecutive days. Plasma blood urea nitrogen (BUN) and creatinine levels were subsequently measured. Malaria-induced renal injury was evidenced as marked increases of BUN and creatinine levels. However, the oral administration of neem leaf extract to PbANKA infected mice for 4 days brought back BUN and creatinine levels to near normalcy, and the highest activity was observed at doses of 1,000 and 2,000 mg/kg. Additionally, no toxic effects were found in normal mice treated with this extract. Hence, neem leaf extract can be considered a potential candidate for protection against renal injury induced by malaria.

  2. Modulation of Lipoprotein Cholesterol Levels in Plasmodium berghei Malarial Infection by Crude Aqueous Extract of Ganoderma lucidum

    Directory of Open Access Journals (Sweden)

    Olarewaju M. Oluba

    2012-01-01

    Full Text Available In this study, attempt is made to establish changes in serum and liver lipoprotein cholesterols accompanying Plasmodium berghei malarial infection in mice treated with aqueous extract of Ganoderma lucidum at 100, 250, and 500 mg/kg body weight in comparison with 15 mg/kg chloroquine (CQ. Significant increases in all the lipoprotein fractions were observed in infected untreated mice compared with normal control mice. Treatment with 100 and 250 mg/kg G. lucidum extract produced significant reduction in serum total cholesterol (TC and low-density cholesterol (LDL-C contents compared with 500 mg/kg G. lucidum and CQ. Treatment with CQ, however, produced significant reduction in hepatic TC and LDL-C compared with the extract. A dose-dependent significant increase in serum high-density lipoprotein cholesterol (HDL-C was observed in the G. lucidum treated mice compared with normal control but significantly lower compared with CQ-treated mice. Liver HDL-C level was significantly higher in CQ-treated mice compared with normal control and significantly lower compared with G. lucidum-treated and infected untreated mice. A dose-dependent effect of the extract was observed in both serum and liver very-low density lipoprotein cholesterol (VLDL-C. The implication of these results is discussed with respect to the parasite survival and proliferation in the serum and liver.

  3. The alveolin IMC1h is required for normal ookinete and sporozoite motility behaviour and host colonisation in Plasmodium berghei.

    Directory of Open Access Journals (Sweden)

    Katrin Volkmann

    Full Text Available Alveolins, or inner membrane complex (IMC proteins, are components of the subpellicular network that forms a structural part of the pellicle of malaria parasites. In Plasmodium berghei, deletions of three alveolins, IMC1a, b, and h, each resulted in reduced mechanical strength and gliding velocity of ookinetes or sporozoites. Using time lapse imaging, we show here that deletion of IMC1h (PBANKA_143660 also has an impact on the directionality and motility behaviour of both ookinetes and sporozoites. Despite their marked motility defects, sporozoites lacking IMC1h were able to invade mosquito salivary glands, allowing us to investigate the role of IMC1h in colonisation of the mammalian host. We show that IMC1h is essential for sporozoites to progress through the dermis in vivo but does not play a significant role in hepatoma cell transmigration and invasion in vitro. Colocalisation of IMC1h with the residual IMC in liver stages was detected up to 30 hours after infection and parasites lacking IMC1h showed developmental defects in vitro and a delayed onset of blood stage infection in vivo. Together, these results suggest that IMC1h is involved in maintaining the cellular architecture which supports normal motility behaviour, access of the sporozoites to the blood stream, and further colonisation of the mammalian host.

  4. The alveolin IMC1h is required for normal ookinete and sporozoite motility behaviour and host colonisation in Plasmodium berghei.

    Science.gov (United States)

    Volkmann, Katrin; Pfander, Claudia; Burstroem, Charlotte; Ahras, Malika; Goulding, David; Rayner, Julian C; Frischknecht, Friedrich; Billker, Oliver; Brochet, Mathieu

    2012-01-01

    Alveolins, or inner membrane complex (IMC) proteins, are components of the subpellicular network that forms a structural part of the pellicle of malaria parasites. In Plasmodium berghei, deletions of three alveolins, IMC1a, b, and h, each resulted in reduced mechanical strength and gliding velocity of ookinetes or sporozoites. Using time lapse imaging, we show here that deletion of IMC1h (PBANKA_143660) also has an impact on the directionality and motility behaviour of both ookinetes and sporozoites. Despite their marked motility defects, sporozoites lacking IMC1h were able to invade mosquito salivary glands, allowing us to investigate the role of IMC1h in colonisation of the mammalian host. We show that IMC1h is essential for sporozoites to progress through the dermis in vivo but does not play a significant role in hepatoma cell transmigration and invasion in vitro. Colocalisation of IMC1h with the residual IMC in liver stages was detected up to 30 hours after infection and parasites lacking IMC1h showed developmental defects in vitro and a delayed onset of blood stage infection in vivo. Together, these results suggest that IMC1h is involved in maintaining the cellular architecture which supports normal motility behaviour, access of the sporozoites to the blood stream, and further colonisation of the mammalian host.

  5. Cardiac Myocyte Diversity and a Fibroblast Network in the Junctional Region of the Zebrafish Heart Revealed by Transmission and Serial Block-Face Scanning Electron Microscopy

    KAUST Repository

    Lafontant, Pascal J.

    2013-08-23

    The zebrafish has emerged as an important model of heart development and regeneration. While the structural characteristics of the developing and adult zebrafish ventricle have been previously studied, little attention has been paid to the nature of the interface between the compact and spongy myocardium. Here we describe how these two distinct layers are structurally and functionally integrated. We demonstrate by transmission electron microscopy that this interface is complex and composed primarily of a junctional region occupied by collagen, as well as a population of fibroblasts that form a highly complex network. We also describe a continuum of uniquely flattened transitional cardiac myocytes that form a circumferential plate upon which the radially-oriented luminal trabeculae are anchored. In addition, we have uncovered within the transitional ring a subpopulation of markedly electron dense cardiac myocytes. At discrete intervals the transitional cardiac myocytes form contact bridges across the junctional space that are stabilized through localized desmosomes and fascia adherentes junctions with adjacent compact cardiac myocytes. Finally using serial block-face scanning electron microscopy, segmentation and volume reconstruction, we confirm the three-dimensional nature of the junctional region as well as the presence of the sheet-like fibroblast network. These ultrastructural studies demonstrate the previously unrecognized complexity with which the compact and spongy layers are structurally integrated, and provide a new basis for understanding development and regeneration in the zebrafish heart. © 2013 Lafontant et al.

  6. Natural Leishmania (Viannia) spp. infections in phlebotomine sand flies (Diptera: Psychodidae) from the Brazilian Amazon region reveal new putative transmission cycles of American cutaneous leishmaniasis.

    Science.gov (United States)

    de Souza, Adelson Alcimar Almeida; Dos Santos, Thiago Vasconcelos; Jennings, Yara Lúcia Lins; Ishikawa, Edna Aoba Yassui; Barata, Iorlando da Rocha; Silva, Maria das Graças Soares; Lima, José Aprígio Nunes; Shaw, Jeffrey; Lainson, Ralph; Silveira, Fernando Tobias

    2016-01-01

    In Amazonian Brazil the etiological agents of American cutaneous leishmaniasis (ACL) belong to at least seven Leishmania species but little is known about the putative phlebotomine sand fly vectors in different biomes. In 2002-2003 a survey of the phlebotomine fauna was undertaken in the "Floresta Nacional do Tapajós", Belterra municipality, in the lower Amazon region, western Pará State, Brazil, where we recently confirmed the presence of a putative hybrid parasite, L. (V.) guyanensis × L. (V.) shawi shawi. Sand flies were collected from Centers for Disease Control (CDC) light traps, Shannon traps and by aspiration on tree bases. Females were dissected and attempts to isolate any flagellate infections were made by inoculating homogenized midguts into Difco B(45) medium. Isolates were characterized by monoclonal antibodies and isoenzyme electrophoresis. A total of 9,704 sand flies, belonging to 68 species or subspecies, were collected. Infections were found in the following sand flies: L. (V.) naiffi with Psychodopygus hirsutus hirsutus (1) and Ps. davisi (2); and L. (V.) shawi shawi with Nyssomyia whitmani (3) and Lutzomyia gomezi (1). These results provide strong evidence of new putative transmission cycles for L. (V.) naiffi and L. (V.) s. shawi.

  7. Variations between the photosynthetic properties of elite and landrace Chinese rice cultivars revealed by simultaneous measurements of 820 nm transmission signal and chlorophyll a fluorescence induction.

    Science.gov (United States)

    Hamdani, Saber; Qu, Mingnan; Xin, Chang-Peng; Li, Ming; Chu, Chengcai; Govindjee; Zhu, Xin-Guang

    2015-04-01

    The difference between the photosynthetic properties of elite and landrace Chinese rice cultivars was studied, using chlorophyll a fluorescence induction (mostly a monitor of Photosystem II activity) and I820 transmission signal (mostly a monitor of Photosystem I activity) to identify potential photosynthetic features differentiating these two groups, which show different degrees of artificial selection and grain yields. A higher fluorescence (related to PSII) IP rise phase and a lower P700(+) (related to PSI) accumulation were observed in the elite cultivars as compared to the landraces. Using these data, together with simulation data from a kinetic model of fluorescence induction, we show that the high IP rise phase and the low P700(+) accumulation can be a result of transient block on electron transfer and traffic jam on the electron acceptor side of PSI under a high [NADPH]/[NADP(+)] ratio. Considering that the ferredoxin NADP(+) reductase (FNR) transcript levels of XS134 (a representative elite cultivars) remains unaffected during the first few minutes of light/dark transition compared to Q4145 (a representative landrace cultivars), which shows a strong decline during the same time range, we propose that the FNR of elite cultivars may take more time to be inactivated in darkness. During this time the FNR enzyme can continue to reduce NADP(+) molecules, leading to initially high [NADPH]/[NADP(+)] ratio during OJIP transient. These data suggested a potential artificial selection of FNR during the breeding process of these examined elite rice cultivars.

  8. Cardiac myocyte diversity and a fibroblast network in the junctional region of the zebrafish heart revealed by transmission and serial block-face scanning electron microscopy.

    Science.gov (United States)

    Lafontant, Pascal J; Behzad, Ali R; Brown, Evelyn; Landry, Paul; Hu, Norman; Burns, Alan R

    2013-01-01

    The zebrafish has emerged as an important model of heart development and regeneration. While the structural characteristics of the developing and adult zebrafish ventricle have been previously studied, little attention has been paid to the nature of the interface between the compact and spongy myocardium. Here we describe how these two distinct layers are structurally and functionally integrated. We demonstrate by transmission electron microscopy that this interface is complex and composed primarily of a junctional region occupied by collagen, as well as a population of fibroblasts that form a highly complex network. We also describe a continuum of uniquely flattened transitional cardiac myocytes that form a circumferential plate upon which the radially-oriented luminal trabeculae are anchored. In addition, we have uncovered within the transitional ring a subpopulation of markedly electron dense cardiac myocytes. At discrete intervals the transitional cardiac myocytes form contact bridges across the junctional space that are stabilized through localized desmosomes and fascia adherentes junctions with adjacent compact cardiac myocytes. Finally using serial block-face scanning electron microscopy, segmentation and volume reconstruction, we confirm the three-dimensional nature of the junctional region as well as the presence of the sheet-like fibroblast network. These ultrastructural studies demonstrate the previously unrecognized complexity with which the compact and spongy layers are structurally integrated, and provide a new basis for understanding development and regeneration in the zebrafish heart.

  9. A Novel Multisensory Integration Task Reveals Robust Deficits in Rodent Models of Schizophrenia: Converging Evidence for Remediation via Nicotinic Receptor Stimulation of Inhibitory Transmission in the Prefrontal Cortex.

    Science.gov (United States)

    Cloke, Jacob M; Nguyen, Robin; Chung, Beryl Y T; Wasserman, David I; De Lisio, Stephanie; Kim, Jun Chul; Bailey, Craig D C; Winters, Boyer D

    2016-12-14

    Atypical multisensory integration is an understudied cognitive symptom in schizophrenia. Procedures to evaluate multisensory integration in rodent models are lacking. We developed a novel multisensory object oddity (MSO) task to assess multisensory integration in ketamine-treated rats, a well established model of schizophrenia. Ketamine-treated rats displayed a selective MSO task impairment with tactile-visual and olfactory-visual sensory combinations, whereas basic unisensory perception was unaffected. Orbitofrontal cortex (OFC) administration of nicotine or ABT-418, an α4β2 nicotinic acetylcholine receptor (nAChR) agonist, normalized MSO task performance in ketamine-treated rats and this effect was blocked by GABAA receptor antagonism. GABAergic currents were also decreased in OFC of ketamine-treated rats and were normalized by activation of α4β2 nAChRs. Furthermore, parvalbumin (PV) immunoreactivity was decreased in the OFC of ketamine-treated rats. Accordingly, silencing of PV interneurons in OFC of PV-Cre mice using DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) selectively impaired MSO task performance and this was reversed by ABT-418. Likewise, clozapine-N-oxide-induced inhibition of PV interneurons in brain slices was reversed by activation of α4β2 nAChRs. These findings strongly imply a role for prefrontal GABAergic transmission in the integration of multisensory object features, a cognitive process with relevance to schizophrenia. Accordingly, nAChR agonism, which improves various facets of cognition in schizophrenia, reversed the severe MSO task impairment in this study and appears to do so via a GABAergic mechanism. Interactions between GABAergic and nAChR receptor systems warrant further investigation for potential therapeutic applications. The novel behavioral procedure introduced in the current study is acutely sensitive to schizophrenia-relevant cognitive impairment and should prove highly valuable for such research.

  10. Phylodynamic analysis reveals CRF01_AE dissemination between Japan and neighboring Asian countries and the role of intravenous drug use in transmission.

    Directory of Open Access Journals (Sweden)

    Teiichiro Shiino

    Full Text Available BACKGROUND: One major circulating HIV-1 subtype in Southeast Asian countries is CRF01_AE, but little is known about its epidemiology in Japan. We conducted a molecular phylodynamic study of patients newly diagnosed with CRF01_AE from 2003 to 2010. METHODS: Plasma samples from patients registered in Japanese Drug Resistance HIV-1 Surveillance Network were analyzed for protease-reverse transcriptase sequences; all sequences undergo subtyping and phylogenetic analysis using distance-matrix-based, maximum likelihood and Bayesian coalescent Markov Chain Monte Carlo (MCMC phylogenetic inferences. Transmission clusters were identified using interior branch test and depth-first searches for sub-tree partitions. Times of most recent common ancestor (tMRCAs of significant clusters were estimated using Bayesian MCMC analysis. RESULTS: Among 3618 patient registered in our network, 243 were infected with CRF01_AE. The majority of individuals with CRF01_AE were Japanese, predominantly male, and reported heterosexual contact as their risk factor. We found 5 large clusters with ≥5 members and 25 small clusters consisting of pairs of individuals with highly related CRF01_AE strains. The earliest cluster showed a tMRCA of 1996, and consisted of individuals with their known risk as heterosexual contacts. The other four large clusters showed later tMRCAs between 2000 and 2002 with members including intravenous drug users (IVDU and non-Japanese, but not men who have sex with men (MSM. In contrast, small clusters included a high frequency of individuals reporting MSM risk factors. Phylogenetic analysis also showed that some individuals infected with HIV strains spread in East and South-eastern Asian countries. CONCLUSIONS: Introduction of CRF01_AE viruses into Japan is estimated to have occurred in the 1990s. CFR01_AE spread via heterosexual behavior, then among persons connected with non-Japanese, IVDU, and MSM. Phylogenetic analysis demonstrated that some viral

  11. Genome Analysis of Clostridium difficile PCR Ribotype 014 Lineage in Australian Pigs and Humans Reveals a Diverse Genetic Repertoire and Signatures of Long-Range Interspecies Transmission

    Science.gov (United States)

    Knight, Daniel R.; Squire, Michele M.; Collins, Deirdre A.; Riley, Thomas V.

    2017-01-01

    Clostridium difficile PCR ribotype (RT) 014 is well-established in both human and porcine populations in Australia, raising the possibility that C. difficile infection (CDI) may have a zoonotic or foodborne etiology. Here, whole genome sequencing and high-resolution core genome phylogenetics were performed on a contemporaneous collection of 40 Australian RT014 isolates of human and porcine origin. Phylogenies based on MLST (7 loci, STs 2, 13, and 49) and core orthologous genes (1260 loci) showed clustering of human and porcine strains indicative of very recent shared ancestry. Core genome single nucleotide variant (SNV) analysis found 42% of human strains showed a clonal relationship (separated by ≤2 SNVs in their core genome) with one or more porcine strains, consistent with recent inter-host transmission. Clones were spread over a vast geographic area with 50% of the human cases occurring without recent healthcare exposure. These findings suggest a persistent community reservoir with long-range dissemination, potentially due to agricultural recycling of piggery effluent. We also provide the first pan-genome analysis for this lineage, characterizing its resistome, prophage content, and in silico virulence potential. The RT014 is defined by a large “open” pan-genome (7587 genes) comprising a core genome of 2296 genes (30.3% of the total gene repertoire) and an accessory genome of 5291 genes. Antimicrobial resistance genotypes and phenotypes varied across host populations and ST lineages and were characterized by resistance to tetracycline [tetM, tetA(P), tetB(P) and tetW], clindamycin/erythromycin (ermB), and aminoglycosides (aph3-III-Sat4A-ant6-Ia). Resistance was mediated by clinically important mobile genetic elements, most notably Tn6194 (harboring ermB) and a novel variant of Tn5397 (harboring tetM). Numerous clinically important prophages (Siphoviridae and Myoviridae) were identified as well as an uncommon accessory gene regulator locus (agr3

  12. Contribution of the Ly49E natural killer receptor in the immune response to Plasmodium berghei infection and control of hepatic parasite development.

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    Jessica Filtjens

    Full Text Available Natural killer (NK cells have different roles in the host response against Plasmodium-induced malaria depending on the stage of infection. Liver NK cells have a protective role during the initial hepatic stage of infection by production of the TH1-type cytokines IFN-γ and TNF-α. In the subsequent erythrocytic stage of infection, NK cells also induce protection through Th1-type cytokines but, in addition, may also promote development of cerebral malaria via CXCR3-induction on CD8(+ T cells resulting in migration of these cells to the brain. We have recently shown that the regulatory Ly49E NK receptor is expressed on liver NK cells in particular. The main objective of this study was therefore to examine the role of Ly49E expression in the immune response upon Plasmodium berghei ANKA infection, for which we compared wild type (WT to Ly49E knockout (KO mice. We show that the parasitemia was higher at the early stage, i.e. at days 6-7 of Plasmodium berghei ANKA infection in Ly49E KO mice, which correlated with lower induction of CD69, IFN-γ and TNF-α in DX5(- liver NK cells at day 5 post-infection. At later stages, these differences faded. There was also no difference in the kinetics and the percentage of cerebral malaria development and in lymphocyte CXCR3 expression in WT versus Ly49E KO mice. Collectively, we show that the immune response against Plasmodium berghei ANKA infection is not drastically affected in Ly49E KO mice. Although NK cells play a crucial role in Plasmodium infection and Ly49E is highly expressed on liver NK cells, the Ly49E NK receptor only has a temporarily role in the immune control of this parasite.

  13. Genome-wide functional analysis of plasmodium protein phosphatases reveals key regulators of parasite development and differentiation

    KAUST Repository

    Guttery, David S.

    2014-07-09

    Reversible protein phosphorylation regulated by kinases and phosphatases controls many cellular processes. Although essential functions for the malaria parasite kinome have been reported, the roles of most protein phosphatases (PPs) during Plasmodium development are unknown. We report a functional analysis of the Plasmodium berghei protein phosphatome, which exhibits high conservation with the P. falciparum phosphatome and comprises 30 predicted PPs with differential and distinct expression patterns during various stages of the life cycle. Gene disruption analysis of P. berghei PPs reveals that half of the genes are likely essential for asexual blood stage development, whereas six are required for sexual development/sporogony in mosquitoes. Phenotypic screening coupled with transcriptome sequencing unveiled morphological changes and altered gene expression in deletion mutants of two N-myristoylated PPs. These findings provide systematic functional analyses of PPs in Plasmodium, identify how phosphatases regulate parasite development and differentiation, and can inform the identification of drug targets for malaria. © 2014 The Authors.

  14. Protection from experimental cerebral malaria with a single dose of radiation-attenuated, blood-stage Plasmodium berghei parasites.

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    Noel J Gerald

    Full Text Available BACKGROUND: Whole malaria parasites are highly effective in inducing immunity against malaria. Due to the limited success of subunit based vaccines in clinical studies, there has been a renewed interest in whole parasite-based malaria vaccines. Apart from attenuated sporozoites, there have also been efforts to use live asexual stage parasites as vaccine immunogens. METHODOLOGY AND RESULTS: We used radiation exposure to attenuate the highly virulent asexual blood stages of the murine malaria parasite P. berghei to a non-replicable, avirulent form. We tested the ability of the attenuated blood stage parasites to induce immunity to parasitemia and the symptoms of severe malaria disease. Depending on the mouse genetic background, a single high dose immunization without adjuvant protected mice from parasitemia and severe disease (CD1 mice or from experimental cerebral malaria (ECM (C57BL/6 mice. A low dose immunization did not protect against parasitemia or severe disease in either model after one or two immunizations. The protection from ECM was associated with a parasite specific antibody response and also with a lower level of splenic parasite-specific IFN-γ production, which is a mediator of ECM pathology in C57BL/6 mice. Surprisingly, there was no difference in the sequestration of CD8+ T cells and CD45+ CD11b+ macrophages in the brains of immunized, ECM-protected mice. CONCLUSIONS: This report further demonstrates the effectiveness of a whole parasite blood-stage vaccine in inducing immunity to malaria and explicitly demonstrates its effectiveness against ECM, the most pathogenic consequence of malaria infection. This experimental model will be important to explore the formulation of whole parasite blood-stage vaccines against malaria and to investigate the immune mechanisms that mediate protection against parasitemia and cerebral malaria.

  15. Unexpected bismuth concentration profiles in metal-organic vapor phase epitaxy-grown Ga(As1−xBix/GaAs superlattices revealed by Z-contrast scanning transmission electron microscopy imaging

    Directory of Open Access Journals (Sweden)

    A. W. Wood

    2015-03-01

    Full Text Available A set of GaAs1−xBix/GaAs multilayer quantum-well structures was deposited by metal-organic vapor phase epitaxy at 390 °C and 420 °C. The precursor fluxes were introduced with the intent of growing discrete and compositionally uniform GaAs1−xBix well and GaAs barrier layers in the epitaxial films. High-resolution high-angle annular-dark-field (or “Z-contrast” scanning transmission electron microscopy imaging revealed concentration profiles that were periodic in the growth direction, but far more complicated in shape than the intended square wave. The observed composition profiles could explain various reports of physical properties measurements that suggest compositional inhomogeneity in GaAs1−xBix alloys as they currently are grown.

  16. Development of an in vitro assay and demonstration of Plasmodium berghei liver-stage inhibition by TRAP-specific CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Rhea J Longley

    Full Text Available The development of an efficacious vaccine against the Plasmodium parasite remains a top priority. Previous research has demonstrated the ability of a prime-boost virally vectored sub-unit vaccination regimen, delivering the liver-stage expressed malaria antigen TRAP, to produce high levels of antigen-specific T cells. The liver-stage of malaria is the main target of T cell-mediated immunity, yet a major challenge in assessing new T cell inducing vaccines has been the lack of a suitable pre-clinical assay. We have developed a flow-cytometry based in vitro T cell killing assay using a mouse hepatoma cell line, Hepa1-6, and Plasmodium berghei GFP expressing sporozoites. Using this assay, P. berghei TRAP-specific CD8+ T cell enriched splenocytes were shown to inhibit liver-stage parasites in an effector-to-target ratio dependent manner. Further development of this assay using human hepatocytes and P. falciparum would provide a new method to pre-clinically screen vaccine candidates and to elucidate mechanisms of protection in vitro.

  17. Antimalarial Properties of Aqueous Crude Extracts of Gynostemma pentaphyllum and Moringa oleifera Leaves in Combination with Artesunate in Plasmodium berghei-Infected Mice.

    Science.gov (United States)

    Somsak, Voravuth; Borkaew, Preeyanuch; Klubsri, Chokdee; Dondee, Kittiyaporn; Bootprom, Panatda; Saiphet, Butsarat

    2016-01-01

    Due to the emergence and spread of malaria parasite with resistance to antimalarial drugs, discovery and development of new, safe, and affordable antimalarial are urgently needed. In this respect, medicinal plant extracts are targets to optimize antimalarial actions and restore efficacy of standard antimalarial drugs. The present study was aimed at determining the antimalarial activities of Gynostemma pentaphyllum and Moringa oleifera leaf extracts in combination with artesunate against Plasmodium berghei-infected mice. P. berghei ANKA maintained by serial passage in ICR mice were used based on intraperitoneal injection of 1 × 10(7) parasitized erythrocytes and subsequent development of parasitemia. These infected mice were used to investigate the antimalarial activity of artesunate (6 mg/kg) in combination with 500, 1,000, and 2,000 mg/kg of G. pentaphyllum and M. oleifera leaf extracts using 4-day suppressive test. It was found that these extracts showed significant (P leaf extract and 35, 40, and 50% for M. oleifera leaf extract. Additionally, artesunate combined with these extracts presented higher antimalarial activity, compared to extract treated alone with percentage of suppression of 78, 91, and 96% for G. pentaphyllum leaf extract and 73, 82, and 91% for M. oleifera leaf extract. The results indicated that combination treatment of G. pentaphyllum or M. oleifera leaf extracts with artesunate was able to increase the antimalarial activity by using low dose of artesunate. Hence, these results justified the combination of these extracts and artesunate in antimalarial herbal remedies.

  18. Plasmodium berghei Δp52&p36 parasites develop independent of a parasitophorous vacuole membrane in Huh-7 liver cells.

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    Ivo H J Ploemen

    Full Text Available The proteins P52 and P36 are expressed in the sporozoite stage of the murine malaria parasite Plasmodium berghei. Δp52&p36 sporozoites lacking expression of both proteins are severely compromised in their capability to develop into liver stage parasites and abort development soon after invasion; presumably due to the absence of a parasitophorous vacuole membrane (PVM. However, a small proportion of P. berghei Δp52&p36 parasites is capable to fully mature in hepatocytes causing breakthrough blood stage infections. We have studied the maturation of replicating Δp52&p36 parasites in cultured Huh-7 hepatocytes. Approximately 50% of Δp52&p36 parasites developed inside the nucleus of the hepatocyte but did not complete maturation and failed to produce merosomes. In contrast cytosolic Δp52&p36 parasites were able to fully mature and produced infectious merozoites. These Δp52&p36 parasites developed into mature schizonts in the absence of an apparent parasitophorous vacuole membrane as shown by immunofluorescence and electron microscopy. Merozoites derived from these maturing Δp52&p36 liver stages were infectious for C57BL/6 mice.

  19. In vivo antimalarial activity of the crude root and fruit extracts of Croton macrostachyus (Euphorbiaceae) against Plasmodium berghei in mice.

    Science.gov (United States)

    Mekonnen, Laychiluh Bantie

    2015-07-01

    Euphorbiaceae (Croton macrostachyus H.; bā dòu) is used in Ethiopian folklore medicine for the treatment of malaria, gonorrhea, diabetes, wounds, fungal infections, and helminths. No scientific investigations have been performed to substantiate these claims. This study aimed to investigate the in vivo antiplasmodial activity of 80% methanol extract of the fruit and the root of Croton macrostachyus H. in a rodent model of malaria. The rodent malaria parasite Plasmodium berghei was used to inoculate healthy 8-week-old male Swiss albino mice weighing 23-27 g. Each of the hydroalcoholic crude extracts (200 mg/kg, 400 mg/kg, and 600 mg/kg) were administered to different groups of mice. The parameters of parasitemia, survival time, body weight, temperature, and packed cell volume were determined using Peter's test and Rane's test. Both extracts significantly inhibited parasitemia and increased survival time in infected mice. Maximum suppression and prolongation were obtained at the highest doses used in the study. The crude extracts prevented loss of weight and temperature, but did not affect the packed cell volume. This study suggests that the root and fruit extracts of the plant both have promising antiplasmodial activity against Plasmodium berghei in a dose-dependent manner, which supports the folkloric use of the plant for treating malaria.

  20. Evaluation of the Effectiveness of Ethanolic Extract of Solanum Surattense against Plasmodium Berghei in Comparison with Chloroquine in Sourian Mice Using in Vivo Tests

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    Garedaghi Yagoob

    2014-07-01

    Full Text Available Objective: Owing to the importance of employing native and traditional medicinal plants with good efficacy against malaria parasites, an ethanolic extract of Solanum surattense was tested on Plasmodium berghei in sourian mice. Moreover, the results were compared with that of the effect of chloroquine on the same parasite. Materials and Methods: In this study, 80 sourian mice were divided into 8 groups, each consisting of 10 animals. The first 7 groups were infected with P. berghei and the last group was used as control. The first 7 groups were given chloroquine, solanum surattense at four different concentrations (20, 100, 300, and 450 mg/kg, and placebo, respectively, and the seventh group did not receive any treatment. The evaluation was done by Rane test. In each group, the level of parasitaemia was determined on days 4 and 7, and compared with values from day 0 (just before treatment in order to record the decline in parasitaemia in treated groups. Results were analyzed using SPSS software and one-way analysis of variance (ANOVA. Results: The results indicated that although all four concentrations of Solanum surattense extract significantly reduced parasitaemia in the infected subjects, the 450 mg/kg solution showed optimal effectiveness on the parasites in comparison with other concentrations and the no-treatment option. Conclusion: We conclude that although the ethanolic extract of Solanum surattense is not as effective as chloroquine in reducing parasitaemia, it can nonetheless cause a significant decrease when compared to control and placebo groups.

  1. C3d-defined complement receptor-binding peptide p28 conjugated to circumsporozoite protein provides protection against Plasmodium berghei.

    Science.gov (United States)

    Bergmann-Leitner, Elke S; Duncan, Elizabeth H; Leitner, Wolfgang W; Neutzner, Albert; Savranskaya, Tatyana; Angov, Evelina; Tsokos, George C

    2007-11-01

    Immune response against circumsporozoite protein (CSP) of Plasmodium berghei, a major surface protein on the sporozoite, confers protection in various murine malaria models. Engineered DNA vaccine encoding CSP and 3 copies of C3d caused an unexpected loss in protection attributed to the binding of C3d to the C-terminal region of CSP. Because the C3d region known as p28 represents the complement receptor (CR) 2-binding motif, we developed a CSP-3 copies of p28 DNA construct (CSP-3p28). CSP-3p28-immunized mice were better protected against P. berghei sporozoites than CSP-immunized mice 6 weeks after the 2nd boost, produced sufficient IgG1 anti-CSP and CSP C-terminus antibody and failed to produce IgG2a. CSP-3C3d-immunized mice were not protected, failed to produce IgG1 and produced high amounts of IgG2a. We conclude that use of the CR2-binding motif of C3d as molecular adjuvant to CSP results in anti-malaria protective immune response probably by targeting the chimeric protein to CR2.

  2. Plasmodium berghei Δp52&p36 parasites develop independent of a parasitophorous vacuole membrane in Huh-7 liver cells.

    Science.gov (United States)

    Ploemen, Ivo H J; Croes, Huib J; van Gemert, Geert-Jan J; Wijers-Rouw, Mietske; Hermsen, Cornelus C; Sauerwein, Robert W

    2012-01-01

    The proteins P52 and P36 are expressed in the sporozoite stage of the murine malaria parasite Plasmodium berghei. Δp52&p36 sporozoites lacking expression of both proteins are severely compromised in their capability to develop into liver stage parasites and abort development soon after invasion; presumably due to the absence of a parasitophorous vacuole membrane (PVM). However, a small proportion of P. berghei Δp52&p36 parasites is capable to fully mature in hepatocytes causing breakthrough blood stage infections. We have studied the maturation of replicating Δp52&p36 parasites in cultured Huh-7 hepatocytes. Approximately 50% of Δp52&p36 parasites developed inside the nucleus of the hepatocyte but did not complete maturation and failed to produce merosomes. In contrast cytosolic Δp52&p36 parasites were able to fully mature and produced infectious merozoites. These Δp52&p36 parasites developed into mature schizonts in the absence of an apparent parasitophorous vacuole membrane as shown by immunofluorescence and electron microscopy. Merozoites derived from these maturing Δp52&p36 liver stages were infectious for C57BL/6 mice.

  3. Anti-malarial effect of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one and green tea extract on erythrocyte-stage Plasmodium berghei in mice

    Institute of Scientific and Technical Information of China (English)

    Phitsinee; Thipubon; Wachiraporn; Tipsuwan; Chairat; Uthaipibull; Sineenart; Santitherakul; Somdet; Srichiratanakool

    2015-01-01

    Objective: To examine the efficacy of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one(CM1) iron chelator and green tea extract(GTE) as anti-malarial activity in Plasmodium berghei(P. berghei) infected mice.Methods: The CM1(0–100 mg/kg/day) and GTE(0–100 mg(-)-epigallocatechin 3-gallate equivalent/kg/day) were orally administered to P. berghei infected mice for consecutive 4 days. Parasitized red blood cells(PRBC) were enumerated by using Giemsa staining microscopic method.Results: CM1 lowered percentage of PRBC in dose-dependent manner with an ED50 value of 56.91 mg/kg, when compared with pyrimethamine(PYR)(ED50= 0.76 mg/kg).GTE treatment did not show any inhibition of the malaria parasite growth. In combined treatment, CM1 along with 0.6 mg/kg PYR significantly inhibited the growth of P. berghei in mice while GTE did not enhance the PYR anti-malarial activity.Conclusions: CM1 would be effective per se and synergize with PYR in inhibiting growth of murine malaria parasites, possibly by limiting iron supply from plasma transferrin and host PRBC cytoplasm, and chelating catalytic iron cstitutive in parasites’ mitochondrial cytochromes and cytoplasmic ribonucleotide reductase. CM1 would be a promising adjuvant to enhance PYR anti-malarial activity and minimize the drug resistance.

  4. Anti-malarial effect of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one and green tea extract on erythrocyte-stage Plasmodium berghei in mice

    Institute of Scientific and Technical Information of China (English)

    Phitsinee Thipubon; Wachiraporn Tipsuwan; Chairat Uthaipibull; Sineenart Santitherakul; Somdet Srichiratanakool

    2015-01-01

    Objective:To examine the efficacy of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) iron chelator and green tea extract (GTE) as anti-malarial activity in Plasmodium berghei (P. berghei ) infected mice. Methods:The CM1 (0–100 mg/kg/day) and GTE (0–100 mg (-)-epigallocatechin 3-gallate equivalent/kg/day) were orally administered to P. berghei infected mice for consecutive 4 days. Parasitized red blood cells (PRBC) were enumerated by using Giemsa staining microscopic method. Results: CM1 lowered percentage of PRBC in dose-dependent manner with an ED50 value of 56.91 mg/kg, when compared with pyrimethamine (PYR) (ED50=0.76 mg/kg). GTE treatment did not show any inhibition of the malaria parasite growth. In combined treatment, CM1 along with 0.6 mg/kg PYR significantly inhibited the growth of P. berghei in mice while GTE did not enhance the PYR anti-malarial activity. Conclusions: CM1 would be effective per se and synergize with PYR in inhibiting growth of murine malaria parasites, possibly by limiting iron supply from plasma transferrin and host PRBC cytoplasm, and chelating catalytic iron constitutive in parasites’ mitochondrial cytochromes and cytoplasmic ribonucleotide reductase. CM1 would be a promising adjuvant to enhance PYR anti-malarial activity and minimize the drug resistance.

  5. Intergenerational Transmission of Volunteering

    NARCIS (Netherlands)

    Bekkers, René

    2007-01-01

    In this article, I investigate the strength of intergenerational transmission of volunteering for non-profit associations in The Netherlands. Data from the Family Survey of the Dutch Population 2000 reveal that there are significant relations between current volunteering and parental volunteering in

  6. Antimalarial Properties of Aqueous Crude Extracts of Gynostemma pentaphyllum and Moringa oleifera Leaves in Combination with Artesunate in Plasmodium berghei-Infected Mice

    Directory of Open Access Journals (Sweden)

    Voravuth Somsak

    2016-01-01

    Full Text Available Due to the emergence and spread of malaria parasite with resistance to antimalarial drugs, discovery and development of new, safe, and affordable antimalarial are urgently needed. In this respect, medicinal plant extracts are targets to optimize antimalarial actions and restore efficacy of standard antimalarial drugs. The present study was aimed at determining the antimalarial activities of Gynostemma pentaphyllum and Moringa oleifera leaf extracts in combination with artesunate against Plasmodium berghei-infected mice. P. berghei ANKA maintained by serial passage in ICR mice were used based on intraperitoneal injection of 1 × 107 parasitized erythrocytes and subsequent development of parasitemia. These infected mice were used to investigate the antimalarial activity of artesunate (6 mg/kg in combination with 500, 1,000, and 2,000 mg/kg of G. pentaphyllum and M. oleifera leaf extracts using 4-day suppressive test. It was found that these extracts showed significant (P<0.05 antimalarial activity in dose-dependent manner with percentage of suppression of 45, 50, and 55% for G. pentaphyllum leaf extract and 35, 40, and 50% for M. oleifera leaf extract. Additionally, artesunate combined with these extracts presented higher antimalarial activity, compared to extract treated alone with percentage of suppression of 78, 91, and 96% for G. pentaphyllum leaf extract and 73, 82, and 91% for M. oleifera leaf extract. The results indicated that combination treatment of G. pentaphyllum or M. oleifera leaf extracts with artesunate was able to increase the antimalarial activity by using low dose of artesunate. Hence, these results justified the combination of these extracts and artesunate in antimalarial herbal remedies.

  7. Dietary supplementation of chloroquine with nigella sativa seed and oil extracts in the treatment of malaria induced in mice with plasmodium berghei

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    Promise Madu Emeka

    2014-01-01

    Full Text Available Background: The aim of the study was to investigate the effects of dietary combination of Nigella sativa seed and oil extracts with chloroquine (CQ, and how these combinations enhance CQ efficacy in mice infected with Plasmodium berghei and their survival rates. Materials and Methods: Chloroquine sensitive P. berghei, NK65 strain was used for the study. This was passaged intraperitoneally into albino mice with a 0.2ml standard inoculum consisting of 10 6 parasitized erythrocyte suspension in phosphate buffer solution (PBS. Parasitaemia was ascertained by microscopical examination of blood films under oil immersion at X100 magnification. Results: Nigella sativa seed in feed (NSSF, NSSF + CQ on day 4, produced 86.1% and 86.0% suppression respectively, while Nigella sativa oil extract in feed (NSOF and in combination with CQ had 86.0% and 99.9% suppression respectively. The degree of suppression with the combination was significantly higher compared to CQ alone (P < 0.001 (36.1%. Complete parasitaemia clearance was obtained on the 20 th and 15 th day of treatment for NSSF, NSSF + CQ respectively, while that for NSOF and NSOF + CQ was on days 26 and 12 respectively. For CQ parasite clearance was 12 days with treatment. Also, the combinastion of 10 mg/kg Nigella sativa oil treatment injected intraperitoneally with oral CQ produced very significant parasite suppression (P < 0.0001 (93%. Survival rate in NSSF and NSOF and in combination with CQ groups was 100 and 60.0% for CQ alone. Conclusion : sThis study shows that the use of Nigella sativa seed and oil extract as dietary supplements in combination with CQ has a potential in enhancing the efficacy of CQ and could be of benefit in management of malaria.

  8. Dietary supplementation of chloroquine with nigella sativa seed and oil extracts in the treatment of malaria induced in mice with plasmodium berghei

    Science.gov (United States)

    Emeka, Promise Madu; Badger-Emeka, Lorina Ineta; Eneh, Chiamaka Maryann; Khan, Tahir Mahmood

    2014-01-01

    Background: The aim of the study was to investigate the effects of dietary combination of Nigella sativa seed and oil extracts with chloroquine (CQ), and how these combinations enhance CQ efficacy in mice infected with Plasmodium berghei and their survival rates. Materials and Methods: Chloroquine sensitive P. berghei, NK65 strain was used for the study. This was passaged intraperitoneally into albino mice with a 0.2ml standard inoculum consisting of 106 parasitized erythrocyte suspension in phosphate buffer solution (PBS). Parasitaemia was ascertained by microscopical examination of blood films under oil immersion at X100 magnification. Results: Nigella sativa seed in feed (NSSF), NSSF + CQ on day 4, produced 86.1% and 86.0% suppression respectively, while Nigella sativa oil extract in feed (NSOF) and in combination with CQ had 86.0% and 99.9% suppression respectively. The degree of suppression with the combination was significantly higher compared to CQ alone (P < 0.001) (36.1%). Complete parasitaemia clearance was obtained on the 20th and 15th day of treatment for NSSF, NSSF + CQ respectively, while that for NSOF and NSOF + CQ was on days 26 and 12 respectively. For CQ parasite clearance was 12 days with treatment. Also, the combinastion of 10 mg/kg Nigella sativa oil treatment injected intraperitoneally with oral CQ produced very significant parasite suppression (P < 0.0001) (93%). Survival rate in NSSF and NSOF and in combination with CQ groups was 100 and 60.0% for CQ alone. Conclusions: This study shows that the use of Nigella sativa seed and oil extract as dietary supplements in combination with CQ has a potential in enhancing the efficacy of CQ and could be of benefit in management of malaria. PMID:24991115

  9. Antimalarial Properties of Aqueous Crude Extracts of Gynostemma pentaphyllum and Moringa oleifera Leaves in Combination with Artesunate in Plasmodium berghei-Infected Mice

    Science.gov (United States)

    Borkaew, Preeyanuch; Klubsri, Chokdee; Dondee, Kittiyaporn; Bootprom, Panatda; Saiphet, Butsarat

    2016-01-01

    Due to the emergence and spread of malaria parasite with resistance to antimalarial drugs, discovery and development of new, safe, and affordable antimalarial are urgently needed. In this respect, medicinal plant extracts are targets to optimize antimalarial actions and restore efficacy of standard antimalarial drugs. The present study was aimed at determining the antimalarial activities of Gynostemma pentaphyllum and Moringa oleifera leaf extracts in combination with artesunate against Plasmodium berghei-infected mice. P. berghei ANKA maintained by serial passage in ICR mice were used based on intraperitoneal injection of 1 × 107 parasitized erythrocytes and subsequent development of parasitemia. These infected mice were used to investigate the antimalarial activity of artesunate (6 mg/kg) in combination with 500, 1,000, and 2,000 mg/kg of G. pentaphyllum and M. oleifera leaf extracts using 4-day suppressive test. It was found that these extracts showed significant (P < 0.05) antimalarial activity in dose-dependent manner with percentage of suppression of 45, 50, and 55% for G. pentaphyllum leaf extract and 35, 40, and 50% for M. oleifera leaf extract. Additionally, artesunate combined with these extracts presented higher antimalarial activity, compared to extract treated alone with percentage of suppression of 78, 91, and 96% for G. pentaphyllum leaf extract and 73, 82, and 91% for M. oleifera leaf extract. The results indicated that combination treatment of G. pentaphyllum or M. oleifera leaf extracts with artesunate was able to increase the antimalarial activity by using low dose of artesunate. Hence, these results justified the combination of these extracts and artesunate in antimalarial herbal remedies. PMID:27872647

  10. Effect of Crocus sativus Stigma (saffron alone or in combination with chloroquine on chloroquine sensitive strain of Plasmodium berghei in mice

    Directory of Open Access Journals (Sweden)

    Pestechian Nader

    2015-10-01

    Full Text Available Introduction: In malaria treatment protocols, treatment failure or drug resistance of synthesized drugs like alkaloids related to quinine, and aminoquinolines are the main problems now. Therefore, discovering efficient drugs or combination therapy of blood schizonticidal drugs with different mechanisms or different targets in the parasite is a crucial effort to solve this problem. In this study, the effectiveness of Crocus sativus Stigma (saffron individually and in combination with chloroquine, was considered against chloroquine–sensitive strain of Plasmodium berghei.Methods: At the first stage, using 4 day suppressive Peter’s test in mice, ED50 and survival times of saffron methanol extract, and its aqueous and ethyl acetate fractions and chloroquine on P. berghei were calculated. Then, based on the toxicity and survival time results, combination therapy was conducted with the best saffron fraction and chloroquine against the parasite.Results: The saffron extract, aqueous and ethyl acetate fractions resulted in suppression of parasitemia with ED50 values of 587.0 ± 78.7, 323.7 ± 37.2, and 508.7 ± 35.6 mg/kg, respectively. Combination of ethyl acetate fraction with chloroquine, potentiated the antimalarial property and the survived percent of the treated mice on days 7, 14, and 28 significantly more than chloroquine or ethyl acetate fraction alone.Conclusion: Saffron and its fractions individually can be effective in reducing the parasitemia in mice. The outcome of combination of ethyl acetate fraction with chloroquine on the mice showed synergistic effect on the chloroquine–sensitive strain of parasite.

  11. AKTIVITAS ANTIMALARIA (IN VIVO KOMBINASI BUAH SIRIH (Piper betle L, DAUN MIYANA (Plectranthus scutellarioides (L. R. BR. MADU DAN KUNING TELUR PADA MEN CIT YANG DIINFEKSI Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Yun Astuti Nugroho

    2012-07-01

    Full Text Available Malaria is a major public health problem in the world and developing countries in particular, causing an estimated 1-2 million deaths per year, an annual incidence of 300-500 million clinical cases and more than 2 billion people were at risk of infection from it. But it is also becoming more difficult to treat malaria due to the increasing drug resistance. Therefore, the need for alternative drugs is acute. This study aims at investigating the in vivo antiplasmodial activity of Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk combination. Methods: A rodent malaria parasite, Plasmodium berghei, was inoculated into Swiss albino mice. The mice were infected with Ixl05 parasites intraperitoneally. The Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk combination were combined and administered by an intra gastric tube daily for seven days starting from the day of parasite inoculation. The control groups received the same amount of solvent (vehicle used to suspend each dose of the herbal drug. Chloroquine was used as a standard drug, administered through the same route. Results: Combination of Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk were observed to inhibit Plasomodium berghei parasitaemia in the Swiss albino mice 100 % on the sixth day. Conclusion: The study could partly confirm the claim in East Sulawesi traditional medicine that the Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk combination has therapeutic values in human malaria. There was, thus, the need to initiate further in-depth investigation by using different experimental models.

  12. HIV Transmission

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... on HIV Syndicated Content Website Feedback HIV/AIDS HIV Transmission Language: English Transmisión del VIH Recommend on ...

  13. Transcending Transmission

    DEFF Research Database (Denmark)

    Schoeneborn, Dennis; Trittin, Hannah

    2013-01-01

    Purpose – Extant research on corporate social responsibility (CSR) communication primarily relies on a transmission model of communication that treats organizations and communication as distinct phenomena. This approach has been criticized for neglecting the formative role of communication...... in the emergence of organizations. This paper seeks to propose to reconceptualize CSR communication by drawing on the “communication constitutes organizations” (CCO) perspective. Design/methodology/approach – This is a conceptual paper that explores the implications of switching from an instrumental...

  14. Comparing histopathology of ICR mice infected with chloroquine-sensitive and chloroquine-resistant strains of Plasmodium berghei%伯氏疟原虫氯喹敏感株和抗性株感染ICR鼠病理变化的比较研究

    Institute of Scientific and Technical Information of China (English)

    陈克强; 宋关鸿

    2001-01-01

    目的:研究伯氏疟原虫(Plasmodium berghei)的抗药性与致病力的关系。方法:比较伯氏疟原虫氯喹敏感株(N)和抗性株(RC)感染ICR鼠的肝、脾、脑、心、肺、肾等重要脏器病理组织学的动态变化。结果:N株感染后,小鼠肝、脾有较多的疟色素沉着,肺脏呈郁血性水肿;脑微血管充血和阻塞;各脏器呈急性炎症的病理变化特点。RC株感染后,小鼠肝、脾脏的病理组织学改变与原虫血症的变化有关。肺脏呈间质性肺炎,各脏器呈慢性增生性炎症的病理变化特点。结论:N株致病力较强,感染后引起宿主死亡的主要原因是感染疟原虫的红细胞对脑微血管内皮细胞的粘附,造成微血管阻塞;RC株致病力较弱,宿主的应答反应在感染早期可能是CD4+Th1相关的迟发型超敏炎症反应,而感染后期是CD4+T h2辅助作用下的抗体依赖性的免疫应答,并在疟原虫的最后清除上起着关键性的作用。%Objective: To understand the relationship between chloroquine resistance and the virulence of Plasmodium berghei. Met hods: Dynamic changes of histopathologic features of livers, spleens, brains, hearts, lungs and kidneys of mice infected with the chloroquine-sensitive (N) and the chloroquine-resistant (RC) strains of P. berghei were compared. Results: In mice infected with the N strain, deposition of heavy hemoz oin in livers and spleens, congestive edema in lungs, and congestion and embolis m in the brain capillaries were observed. The histopathologic features revealed ac ute inflammatory reaction. In mice infected with the RC strain, histopathologic variations of livers and spleens were associated with changes of parasitemia. In terstitial pneumonia was displayed in lungs. There were chronic histopathologic changes of the organs in the mice infected with RC strain. Conclusion: The mice infected by the N strain with potent virulence die due to adher ence of

  15. Activation and exhaustion of antigen-specific CD8(+) T cells occur in different splenic compartments during infection with Plasmodium berghei.

    Science.gov (United States)

    Bayarsaikhan, Ganchimeg; Miyakoda, Mana; Yamamoto, Kazuo; Kimura, Daisuke; Akbari, Masoud; Yuda, Masao; Yui, Katsuyuki

    2017-06-01

    The spleen is the major organ in which T cells are primed during infection with malaria parasites. However, little is known regarding the dynamics of the immune responses and their localization within the splenic tissue during malaria infection. We examined murine CD8(+) T cell responses during infection with Plasmodium berghei using recombinant parasites expressing a model antigen ovalbumin (OVA) protein and compared the responses with those elicited by Listeria monocytogenes expressing the same antigen. OVA-specific CD8(+) T cells were mainly activated in the white pulp of the spleen during malaria infection, as similarly observed during Listeria infection. However, the fates of these activated CD8(+) T cells were distinct. During infection with malaria parasites, activated CD8(+) T cells preferentially accumulated in the red pulp and/or marginal zone, where cytokine production of OVA-specific CD8(+) T cells decreased, and the expression of multiple inhibitory receptors increased. These cells preferentially underwent apoptosis, suggesting that T cell exhaustion mainly occurred in the red pulp and/or marginal zone. However, during Listeria infection, OVA-specific CD8(+) T cells only transiently expressed inhibitory receptors in the white pulp and maintained their ability to produce cytokines and become memory cells. These results highlighted the distinct fates of CD8(+) T cells during infection with Plasmodium parasites and Listeria, and suggested that activation and exhaustion of specific CD8(+) T cells occurred in distinct spleen compartments during infection with malaria parasites.

  16. Modulatory effect of crude aqueous extract of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Higher Basidiomycetes), on hematological and antioxidant indices in Plasmodium berghei-infected mice.

    Science.gov (United States)

    Oluba, Olarewaju M; Adebisi, Kayode E; Eidangbe, George O; Odutuga, Adewale A; Onyeneke, E Chukwu

    2014-01-01

    Hematological and antioxidant effects of the aqueous extract of fruiting bodies of Ganoderma lucidum were evaluated in Plasmodium berghei-infected mice. Extract was administered at doses of 100, 250, and 500 mg/kg body weight by an intragastric tube once daily for 14 d starting from the fourth day after parasite inoculation. At the end of treatment period, mice in each group were sacrificed and blood was collected for hematological and biochemical analyses. A significant (P<0.05) decrease was observed in serum malondialdehyde content with a corresponding significant (P<0.05) increase in superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and glucose 6-phosphate dehydrogenase activities in the extract-treated groups compared to the infected but untreated group. The results obtained suggest that crude aqueous extract of G. lucidum fruiting bodies possesses potent antioxidant activity that protects hemoglobin against Plasmodium-induced oxidative damage. These findings seem to justify the use of the plant in traditional African and Chinese medicine as an anti-inflammatory and antimicrobial agent.

  17. 伯氏疟原虫氯喹抗性逆转的实验观察%Search for reverser of chloroquine-resistance in Plasmodium berghei

    Institute of Scientific and Technical Information of China (English)

    吴嘉彤; 兰勤娴; 王琴美; 潘星清

    2010-01-01

    Objective To search for reverser of chloroquine-resistance in Plasmodium berghei (P.berghei) ANKA. Methods Seventy-two healthy Kunming mice were each infected with chloroquine sensitive (CS) or chloroquine resistance (CR) P. berghei ANKA respectively, then treated with various schedule of reversal agents C-2832 、D-6182 or ketotifen(Ket) respectively with or without co-administration of low dose (5%ED90) of chloroquine (CQ). Schedule 1: mice infected with CS were randomly distributed into 4 groups, 6 mice in each group, 30 min after infection,then treated i.g. with D-6182, C-2832, Ket or 0. 1% gum tragacanth(control) respectively for 5 consecutive days. The parasitemia of each experiment group was then determined by routine microscopic examination on blood smears from the tail blood of each mouse from D1 to D7.Schedule 2:mice infected with CR were randomly distriduted into 8 groups, 6 mice in each group, 3 d after infection, then treated i.g. with D-6182, C-2832, Ket, chloroquine or 0. 1% gum tragacanth (control) with or without co-administration of 12 mg/(kg · d) chloroquine (5% ED90) 2 h after the first administration for 5 consecutive days. The parasitemia of each experiment group was then determined microscopically by examination on blood smears from the tail blood of each mouse from D4 to D7. The reduction rates of each group were calculated and compared between the groups with or without treatment of reverser. Results 1. The parasitemia of mice infected with CS was going up daily from D1 to D4 and reached the peak on D4 in all groups administered with 80 mg/(kg · d) D-6182, 120 mg/(kg · d) C-2832 or 10 mg/(kg · d) Ket for5 d. From D5 the parasitemia kept going up in control group while it kept at the level of D4 in all treated groups. 2. Chloroquine 12 mg/(kg · d) administered i.g. 2 h after administration of C-2832 or D-6182 or Ket for 5 d(D3-D7) could reach 97.77%, 99.28% or 96.73% of reduction rate of parasitemia on D4 and 99.81%, 98.87% or 100

  18. The genotype of early-transmitting HIV gp120s promotes α (4) β(7)-reactivity, revealing α (4) β(7) +/CD4+ T cells as key targets in mucosal transmission.

    Science.gov (United States)

    Nawaz, Fatima; Cicala, Claudia; Van Ryk, Donald; Block, Katharine E; Jelicic, Katija; McNally, Jonathan P; Ogundare, Olajumoke; Pascuccio, Massimiliano; Patel, Nikita; Wei, Danlan; Fauci, Anthony S; Arthos, James

    2011-02-01

    Mucosal transmission of HIV is inefficient. The virus must breach physical barriers before it infects mucosal CD4+ T cells. Low-level viral replication occurs initially in mucosal CD4+ T cells, but within days high-level replication occurs in Peyer's patches, the gut lamina propria and mesenteric lymph nodes. Understanding the early events in HIV transmission may provide valuable information relevant to the development of an HIV vaccine. The viral quasispecies in a donor contracts through a genetic bottleneck in the recipient, such that, in low-risk settings, infection is frequently established by a single founder virus. Early-transmitting viruses in subtypes A and C mucosal transmission tend to encode gp120s with reduced numbers of N-linked glycosylation sites at specific positions throughout the V1-V4 domains, relative to typical chronically replicating isolates in the donor quasispecies. The transmission advantage gained by the absence of these N-linked glycosylation sites is unknown. Using primary α₄β₇/CD4+ T cells and a flow-cytometry based steady-state binding assay we show that the removal of transmission-associated N-linked glycosylation sites results in large increases in the specific reactivity of gp120 for integrin-α₄β₇. High-affinity for integrin α₄β₇, although not found in many gp120s, was observed in early-transmitting gp120s that we analyzed. Increased α₄β₇ affinity is mediated by sequences encoded in gp120 V1/V2. α₄β₇-reactivity was also influenced by N-linked glycosylation sites located in C3/V4. These results suggest that the genetic bottleneck that occurs after transmission may frequently involve a relative requirement for the productive infection of α₄β₇+/CD4+ T cells. Early-transmitting gp120s were further distinguished by their dependence on avidity-effects to interact with CD4, suggesting that these gp120s bear unusual structural features not present in many well-characterized gp120s derived from

  19. The genotype of early-transmitting HIV gp120s promotes α (4 β(7-reactivity, revealing α (4 β(7 +/CD4+ T cells as key targets in mucosal transmission.

    Directory of Open Access Journals (Sweden)

    Fatima Nawaz

    2011-02-01

    Full Text Available Mucosal transmission of HIV is inefficient. The virus must breach physical barriers before it infects mucosal CD4+ T cells. Low-level viral replication occurs initially in mucosal CD4+ T cells, but within days high-level replication occurs in Peyer's patches, the gut lamina propria and mesenteric lymph nodes. Understanding the early events in HIV transmission may provide valuable information relevant to the development of an HIV vaccine. The viral quasispecies in a donor contracts through a genetic bottleneck in the recipient, such that, in low-risk settings, infection is frequently established by a single founder virus. Early-transmitting viruses in subtypes A and C mucosal transmission tend to encode gp120s with reduced numbers of N-linked glycosylation sites at specific positions throughout the V1-V4 domains, relative to typical chronically replicating isolates in the donor quasispecies. The transmission advantage gained by the absence of these N-linked glycosylation sites is unknown. Using primary α₄β₇/CD4+ T cells and a flow-cytometry based steady-state binding assay we show that the removal of transmission-associated N-linked glycosylation sites results in large increases in the specific reactivity of gp120 for integrin-α₄β₇. High-affinity for integrin α₄β₇, although not found in many gp120s, was observed in early-transmitting gp120s that we analyzed. Increased α₄β₇ affinity is mediated by sequences encoded in gp120 V1/V2. α₄β₇-reactivity was also influenced by N-linked glycosylation sites located in C3/V4. These results suggest that the genetic bottleneck that occurs after transmission may frequently involve a relative requirement for the productive infection of α₄β₇+/CD4+ T cells. Early-transmitting gp120s were further distinguished by their dependence on avidity-effects to interact with CD4, suggesting that these gp120s bear unusual structural features not present in many well-characterized gp120s

  20. Teste de hemaglutinação na sorologia da malária humana empregando hemácias parasitadas pelo Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Maria Carmen Arroyo Sanchez-Ruiz

    1985-06-01

    Full Text Available Foi padronizado um teste de hemaglutinação para a sorologia da malária humana, com reagente constituído de suspensão de hemácias de camundongos infectadas pelo Plasmodium berghei e preservadas por fixação aldeídica. Em pacientes com parasitemia por P. falciparum ou P. vivax obteve-se uma sensibilidade de 98,9% nos 88 casos estudados, o teste apresentando títulos entre 40 e 640. Para o grupo de 476 soros de indivíduos não-maláricos, obteve-se uma especificidade de 96,0%. O teste apresentou elevada reprodutibilidade, mesmo para diferentes lotes de antígenos. Nos 200 soros, obtidos ao acaso, de indivíduos de área endêmica, o teste apresentou positividade de 48,5%, contra 88,0% do teste de imunofluorescência-IgG. A baixa positividade pode ser devida a que o teste de hemaglutinação detecta anticorpos IgM. Após tratamento com 2-mercaptoetanol, todos os soros de pacientes com parasitemia tornaram-se não reagentes. Em relação ao teste de imunofluorescência-IgG, o teste de hemaglutinação apresentou índice de co-positívidade de 0,989 para os soros de maláricos com parasitemia. Para os soros de não-maláricos o teste de hemaglutinação apresentou índice de co-negatividade de 0,969. Por outro lado, no grupo de soros de área endêmica, o índice de co-positividade foi de 0,528 e o de co-negatividade, de 0,833.A hemagglutination test is described for human malaria serodiagnosis with aldehyde-fixed Plasmodium berghei infected mouse erythrocytes. In patients with a P. falciparum or P. vivax patent parasitemia positive results were seen in 98.9% ofthe 88 cases tested. Titres rangedfrom 40 to 640. A 96.0% specificity wasfoundfor 476 non-malarialpatients. A close reproducibility was observed forthe test, even for dijferent reagent batches. The test was positive in 48.5% of 200 residents in malaria endemic areas, taken at random. These subjects showed 88.0% positivity of the IgG-immunofluorescence test. This lower positivity for

  1. Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Fink, S.; Porter, K.; Mudd, C.; Rogers, J.

    2011-02-01

    The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations.

  2. Drug intervention effects on thrombocytopenia due to Plasmodium berghei infection in mice%鼠疟原虫引起血小板减少药物干预效果的观察

    Institute of Scientific and Technical Information of China (English)

    区德锦; 韦海艳; 邹春燕; 崔立旺; 黄亚铭

    2013-01-01

    Objective To analyze the common antipyretics,antibiotics and corticosteroids on thrombocytopenia due to Plasmodium berghei infection in mice. Methods Healthy Kunming mice were intraperitoneally inoculated with Plasmodium berghei and treated with β -Iactams,quinolones, antipyretics and corticosteroids at dose of 10 times that of human dose for 3 days by irrigation or intramuscular injection when platelet count markedly below normal value.Then blood samples were obtained for every 12 hours and platelet count was recorded. Observation group consisted of five mice and each drug was tested in a group and with control group. Results The normal mice platelet count averaged for 256 × 109/L and the platelet count dropped to an average count of 90 ×109/L in each group 8 days after infection with Plasmodium berghei. The platelet count returned to 201 × 109/L in azithromycin-treated group only 3 days after treated with various antibiotics and muscular injection of aminophenazone and dexamethasone.and other antibiotics, antipyretic and corticosteroids showed no effect on thrombocytopenia recovery in mice infected with Plasmodium berghei. Conclusions Except azithromycin,aminophenazone,amoxicillin,levofloxacin and dexamethasone showed on effects on platelet recovery in mice infected with Plasmodium berghei.%目的 了解退烧药、抗生素及激素对感染鼠疟原虫引起的血小板减少是否具有恢复的效果.方法 健康昆明小鼠腹腔接种感染伯氏鼠疟原虫,当感染鼠血小板明显低于正常值后,分别采用临床常用的大环内酯类、β内酰胺类和喹诺酮类抗生素、退烧药及激素类药物按照人体治疗量的10倍灌服或肌注方法给药3d,每12h采血1次做血小板计数观察.每5只小鼠为一个观察试验组,每种药物采用一组小鼠试验观察取平均数据,并设正常对照组. 结果 正常鼠血小板平均计数为256 × 109/L.健康鼠感染鼠疟原虫后第8d,各组感

  3. Revealing the True Incidence of Pandemic A(H1N1)pdm09 Influenza in Finland during the First Two Seasons - An Analysis Based on a Dynamic Transmission Model.

    Science.gov (United States)

    Shubin, Mikhail; Lebedev, Artem; Lyytikäinen, Outi; Auranen, Kari

    2016-03-01

    The threat of the new pandemic influenza A(H1N1)pdm09 imposed a heavy burden on the public health system in Finland in 2009-2010. An extensive vaccination campaign was set up in the middle of the first pandemic season. However, the true number of infected individuals remains uncertain as the surveillance missed a large portion of mild infections. We constructed a transmission model to simulate the spread of influenza in the Finnish population. We used the model to analyse the two first years (2009-2011) of A(H1N1)pdm09 in Finland. Using data from the national surveillance of influenza and data on close person-to-person (social) contacts in the population, we estimated that 6% (90% credible interval 5.1 - 6.7%) of the population was infected with A(H1N1)pdm09 in the first pandemic season (2009/2010) and an additional 3% (2.5 - 3.5%) in the second season (2010/2011). Vaccination had a substantial impact in mitigating the second season. The dynamic approach allowed us to discover how the proportion of detected cases changed over the course of the epidemic. The role of time-varying reproduction number, capturing the effects of weather and changes in behaviour, was important in shaping the epidemic.

  4. Essays on electricity transmission investment and financial transmission rights

    Science.gov (United States)

    Shang, Wenzhuo

    The U.S. electric power industry has been going through fundamental restructuring and realignment since the 1990's. Many issues and problems have emerged during the transition, and both economists and engineers have been looking for the solutions fervently. In this dissertation, which consists primarily of three essays, we apply economics theory and techniques to the power industry and address two related issues, transmission investment and financial transmission rights (FTRs). The first essay takes the decentralized perspective and investigates the efficiency attribute of market-based transmission investment under perfect competition. We clarify, for the first time, the nature of the externality created by loop flows that causes transmission investment to be inefficient. Our findings have important implications for better understanding of transmission market design and creating incentives for efficient transmission investment. In the second essay, we define several rules for allocating transmission investment cost within the framework of cooperative game theory. These rules provide fair, stable or efficient cost allocations in theory and are good benchmarks against which the allocation mechanism in practice can be compared and improved upon. In the last essay, we make exploratory efforts in analyzing and assessing empirically the performance of the Midwest independent system operator (MISO) FTR auction market. We reveal some stylized facts about this young market and find that it is not efficient under the risk-neutrality assumption. We also point out and correct the drawbacks in previous related work and suggest about more complete empirical work in future. In all, this dissertation makes both theoretic and empirical analysis of the two hot issues related to the power industry and comes up with findings that have important implications for the development of this industry.

  5. RESEARCH OF DYNAMIC CHARACTERIATIC FOR TRANSMISSION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The kinetic precision of transmission chain is a key problem in the research of gear cutting machine transmission system.The traditional point of view is to consider the transmission chain as a geometrical meshing system,thus it is deemed that the kinetic precision of the transmission chain only depends on the manufacturing and assembly errors of its transmission parts.But further research reveals that the kinetic precision of transmission system is closely related with the system dynamic effects.Therefore,from the dynamic point of view,it is discerned that not only deems the transmission chain as a geometrical meshing system but also considers it as a dynamic system performing with torsional vibration.On the basis of analyses and processes of measuring data of samples from tests of cutting machine's kinetic precision of transmission chain,the results represent that the influences of dynamic characteristics of the transmission system on its kinetic precision is non-negligible.Experimental methods for discerning the transfer function of torsional vibration of gear transmission system and experimental results have been given.

  6. An overview of malaria transmission from the perspective of Amazon Anopheles vectors

    Directory of Open Access Journals (Sweden)

    Paulo FP Pimenta

    2015-02-01

    Full Text Available In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.

  7. Reduction of malaria transmission by transgenic mosquitoes expressing an antisporozoite antibody in their salivary glands.

    Science.gov (United States)

    Sumitani, M; Kasashima, K; Yamamoto, D S; Yagi, K; Yuda, M; Matsuoka, H; Yoshida, S

    2013-02-01

    We have previously developed a robust salivary gland-specific expression system in transgenic Anopheles stephensi mosquitoes. To establish transgenic mosquito lines refractory to Plasmodium falciparum using this system, we generated a transgenic mosquito harbouring the gene encoding an anti-P. falciparum circumsporozoite protein (PfCSP) single-chain antibody (scFv) fused to DsRed in a secretory form (mDsRed-2A10 scFv). Fluorescence microscopy showed that the mDsRed-2A10 scFv was localized in the secretory cavities and ducts of the salivary glands in a secreted form. To evaluate P. falciparum transmission-blocking in a rodent malaria model, a transgenic Plasmodium berghei line expressing PfCSP in place of PbCSP (PfCSP/Pb) was constructed. The PfCSP/Pb parasites were able to bind to the mDsRed-2A10 scFv in the salivary glands of the transgenic mosquitoes. Importantly, the infectivity of the transgenic mosquitoes to mice was strongly impaired, indicating that the parasites had been inactivated. These results suggest that salivary gland-specific expression of antisporozoite molecules could be a promising strategy for blocking malaria transmission to humans.

  8. Ambiguity Revealed

    OpenAIRE

    Subir Bose; Matthew Polisson; Ludovic Renou

    2012-01-01

    We derive necessary and suffcient conditions for data sets composed of state-contingent prices and consumption to be consistent with two prominent models of decision making under ambiguity: variational preferences and smooth ambiguity. The revealed preference conditions for the maxmin expected utility and subjective expected utility models are characterized as special cases.

  9. Ambiguity revealed

    OpenAIRE

    Bayer, Ralph-C; Bose, Subir; Polisson, Matthew; Renou, Ludovic

    2013-01-01

    We derive necessary and sufficient conditions for data sets composed of state-contingent prices and consumption to be consistent with two prominent models of decision making under uncertainty: variational preferences and smooth ambiguity. The revealed preference conditions for subjective expected utility, maxmin expected utility, and multiplier preferences are characterised as special cases. We implement our tests on data from a portfolio choice experiment.

  10. 4-(1H)-Quinolones and 1,2,3,4-Tetrahydroacridin-9(10H)-ones prevent the transmission of Plasmodium falciparum to Anopheles freeborni.

    Science.gov (United States)

    Sáenz, Fabián E; Lacrue, Alexis N; Cross, R Matthew; Maignan, Jordany R; Udenze, Kenneth O; Manetsch, Roman; Kyle, Dennis E

    2013-12-01

    Malaria kills approximately 1 million people a year, mainly in sub-Saharan Africa. Essential steps in the life cycle of the parasite are the development of gametocytes, as well as the formation of oocysts and sporozoites, in the Anopheles mosquito vector. Preventing transmission of malaria through the mosquito is necessary for the control of the disease; nevertheless, the vast majority of drugs in use act primarily against the blood stages. The study described herein focuses on the assessment of the transmission-blocking activities of potent antierythrocytic stage agents derived from the 4(1H)-quinolone scaffold. In particular, three 3-alkyl- or 3-phenyl-4(1H)-quinolones (P4Qs), one 7-(2-phenoxyethoxy)-4(1H)-quinolone (PEQ), and one 1,2,3,4-tetrahydroacridin-9(10H)-one (THA) were assessed for their transmission-blocking activity against the mosquito stages of the human malaria parasite (Plasmodium falciparum) and the rodent parasite (P. berghei). Results showed that all of the experimental compounds reduced or prevented the exflagellation of male gametocytes and, more importantly, prevented parasite transmission to the mosquito vector. Additionally, treatment with ICI 56,780 reduced the number of sporozoites that reached the Anopheles salivary glands. These findings suggest that 4(1H)-quinolones, which have activity against the blood stages, can also prevent the transmission of Plasmodium to the mosquito and, hence, are potentially important drug candidates to eradicate malaria.

  11. The automotive transmission book

    CERN Document Server

    Fischer, Robert; Jürgens, Gunter; Najork, Rolf; Pollak, Burkhard

    2015-01-01

    This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors, and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles.

  12. Bordetella pertussis transmission.

    Science.gov (United States)

    Trainor, Elizabeth A; Nicholson, Tracy L; Merkel, Tod J

    2015-11-01

    Bordetella pertussis and B. bronchiseptica are Gram-negative bacterial respiratory pathogens. Bordetella pertussis is the causative agent of whooping cough and is considered a human-adapted variant of B. bronchiseptica. Bordetella pertussis and B. bronchiseptica share mechanisms of pathogenesis and are genetically closely related. However, despite the close genetic relatedness, these Bordetella species differ in several classic fundamental aspects of bacterial pathogens such as host range, pathologies and persistence. The development of the baboon model for the study of B. pertussis transmission, along with the development of the swine and mouse model for the study of B. bronchiseptica, has enabled the investigation of different aspects of transmission including the route, attack rate, role of bacterial and host factors, and the impact of vaccination on transmission. This review will focus on B. pertussis transmission and how animal models of B. pertussis transmission and transmission models using the closely related B. bronchiseptica have increased our understanding of B. pertussis transmission.

  13. Enhanced broadband optical transmission in metallized woodpiles

    DEFF Research Database (Denmark)

    Malureanu, Radu; Alabastri, A.; Cheng, W.;

    2011-01-01

    We present an optimized isotropic metal deposition technique used for covering three-dimensional polymer structures with a 50 nm smooth silver layer. The technology allows fast and isotropic coating of complex 3D dielectric structures with thin silver layers. Transmission measurements of 3D...... metallized woodpiles reveal a new phenomenon of enhanced optical transmission in broadband range (up to 300 nm) in the near IR....

  14. TRANSMISSION LINE FAULT ANALYSIS USING WAVELET THEORY

    Directory of Open Access Journals (Sweden)

    Ravindra Malkar

    2012-06-01

    Full Text Available This paper describes a Wavelet transform technique to analyze power system disturbance such as transmission line faults with Biorthogonal and Haar wavelets. In this work, wavelet transform based approach,which is used to detect transmission line faults, is proposed. The coefficient of discrete approximation of the dyadic wavelet transform with different wavelets are used to be an index for transmission line fault detection and faulted – phase selection and select which wavelet is suitable for this application. MATLAB/Simulation is used to generate fault signals. Simulation results reveal that the performance of the proposed fault detection indicator is promising and easy to implement for computer relaying application.

  15. 遗传减毒伯氏疟原虫ANKA株的构建及其免疫保护效应%Establishment of a genetically attenuated strain of Plasmodium berghei ANKA and its immune protective effect

    Institute of Scientific and Technical Information of China (English)

    丁艳; 谭章平; 卢潇; 徐文岳; 付雍

    2016-01-01

    目的:构建遗传减毒伯氏疟原虫ANKA株(Plasmodium berghei ANKA,P.b ANKA),并用此减毒疟原虫株免疫C57BL/6J小鼠观察免疫保护效果。方法分别扩增UIS3基因编码序列两端的非编码区5′UTR和3′UTR及用于筛选的抗性标记hDHFR,然后利用融合PCR原理,扩增全长同源重组片段(5′UTR+hDHFR+3′UTR),最后常规PCR扩增获得大量线性化同源重组片段并纯化。体外培养富集伯氏疟原虫ANKA株的成熟裂殖体,将线性化同源重组片段通过电转的方式导入裂殖体中并接种到小鼠体内,再对转化后的疟原虫进行筛选和鉴定,最后用构建成功的减毒伯氏疟原虫ANKA株免疫小鼠并攻击,观察减毒株的免疫保护效力。结果成功扩增3个独立片段5′UTR、hDHFR和3′UTR ,长度分别为798、1628和759 bp ,后经融合 PCR 反应形成全长重组片段5′UTR+hDHFR+3′UTR ,长度为3185 bp。转化至裂殖体后经筛选鉴定获得遗传减毒伯氏疟原虫ANKA株,将此遗传减毒株免疫小鼠后攻击,小鼠红内期原虫率为0%,脑型疟发生率为0%,存活率为100%,可使其完全抵御野生型疟原虫感染。结论成功构建遗传减毒伯氏疟原虫ANKA株,此减毒株对小鼠的免疫保护率为100%,此模型的建立可为研究红前期疫苗免疫保护机制奠定基础。%Objective To construct a genetically attenuated strain of Plasmodium berghei ANKA, and observe the immune protective effect. Methods The PCR amplified 5′untranslated region and 3′untranslated region of UIS3 gene coding sequence and resistance marker hDHFR fragments were used for the construction of full-length homologous recombination fragments ( 5′UTR+hDHFR+3′UTR ) by fusion PCR . The linearized homologous recombination fragments were introduced into mature schizonts which were enriched through in vitro culture and inoculated into the mice. Screening and identification of

  16. Understanding ebola virus transmission.

    Science.gov (United States)

    Judson, Seth; Prescott, Joseph; Munster, Vincent

    2015-02-03

    An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus.

  17. Series Transmission Line Transformer

    Science.gov (United States)

    Buckles, Robert A.; Booth, Rex; Yen, Boris T.

    2004-06-29

    A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

  18. Revealing Rembrandt

    Directory of Open Access Journals (Sweden)

    Andrew J Parker

    2014-04-01

    Full Text Available The power and significance of artwork in shaping human cognition is self-evident. The starting point for our empirical investigations is the view that the task of neuroscience is to integrate itself with other forms of knowledge, rather than to seek to supplant them. In our recent work, we examined a particular aspect of the appreciation of artwork using present-day functional magnetic resonance imaging (fMRI. Our results emphasised the continuity between viewing artwork and other human cognitive activities. We also showed that appreciation of a particular aspect of artwork, namely authenticity, depends upon the co-ordinated activity between the brain regions involved in multiple decision making and those responsible for processing visual information. The findings about brain function probably have no specific consequences for understanding how people respond to the art of Rembrandt in comparison with their response to other artworks. However, the use of images of Rembrandt’s portraits, his most intimate and personal works, clearly had a significant impact upon our viewers, even though they have been spatially confined to the interior of an MRI scanner at the time of viewing. Neuroscientific studies of humans viewing artwork have the capacity to reveal the diversity of human cognitive responses that may be induced by external advice or context as people view artwork in a variety of frameworks and settings.

  19. Poverty and price transmission

    DEFF Research Database (Denmark)

    Elleby, Christian

    A key parameter determining the welfare impact from a world market shock is the transmission elasticity which measures the average domestic response to an international price change. Many studies have estimated price transmission elasticities for a large number of countries but the variation in t...

  20. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  1. Interspecies transmission of prions.

    Science.gov (United States)

    Afanasieva, E G; Kushnirov, V V; Ter-Avanesyan, M D

    2011-12-01

    Mammalian prions are infectious agents of proteinaceous nature that cause several incurable neurodegenerative diseases. Interspecies transmission of prions is usually impeded or impossible. Barriers in prion transmission are caused by small interspecies differences in the primary structure of prion proteins. The barriers can also depend on the strain (variant) of a transmitted prion. Interspecies barriers were also shown for yeast prions, which define some heritable phenotypes. Yeast prions reproduce all the main traits of prion transmission barriers observed for mammals. This allowed to show that the barrier in prion transmission can be observed even upon copolymerization of two prionogenic proteins. Available data allow elucidation of the mechanisms that impede prion transmission or make it impossible.

  2. Nonlinear magnetoinductive transmission lines

    CERN Document Server

    Lazarides, Nikos; Tsironis, G P

    2011-01-01

    Power transmission in one-dimensional nonlinear magnetic metamaterials driven at one end is investigated numerically and analytically in a wide frequency range. The nonlinear magnetic metamaterials are composed of varactor-loaded split-ring resonators which are coupled magnetically through their mutual inductances, forming thus a magnetoiductive transmission line. In the linear limit, significant power transmission along the array only appears for frequencies inside the linear magnetoinductive wave band. We present analytical, closed form solutions for the magnetoinductive waves transmitting the power in this regime, and their discrete frequency dispersion. When nonlinearity is important, more frequency bands with significant power transmission along the array may appear. In the equivalent circuit picture, the nonlinear magnetoiductive transmission line driven at one end by a relatively weak electromotive force, can be modeled by coupled resistive-inductive-capacitive (RLC) circuits with voltage-dependent cap...

  3. METHODS OF POLYMODAL INFORMATION TRANSMISSION

    Directory of Open Access Journals (Sweden)

    O. O. Basov

    2015-03-01

    Full Text Available The research results upon the application of the existing information transmission methods in polymodal info communication systems are presented herein. The analysis of the existing commutation ways and multiplexing schemes has revealed that modern means of telecommunication are capable of providing polymodal information delivery with the required quality to the customer correspondent terminal. Under these conditions substantial capacity resource consumption in the data transmission networks with a simultaneous static time multiplexing is required, however, it is easier to achieve the modality synchronization within that kind of an infrastructure. The data networks with a static time multiplexing demand employing more sophisticated supporting algorithms of the guaranteed data blocks delivery quality. However, due to the stochastic data blocks delays modality synchronizing during the off-line processing is more difficult to provide. Nowadays there are objective preconditions for a data networking realization which is invariable to the applied transmission technology. This capability is defined by a wide (person-to-person application of the optical technologies in the transport infrastructure of the polymodal info communication systems. In case of the availability of the customer terminal and networking functioning matching mode it becomes possible to organize channels in the latter which can adaptively select the most effective networking technology according to the current volume allocation and modality types in the messages.

  4. Understanding Ebola Virus Transmission

    Directory of Open Access Journals (Sweden)

    Seth Judson

    2015-02-01

    Full Text Available An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus.

  5. Tractor Transmissions. A Teaching Reference.

    Science.gov (United States)

    American Association for Agricultural Engineering and Vocational Agriculture, Athens, GA.

    The manual was developed as a reference for teaching students about transmissions in farm tractors. The manual is divided into five sections: (1) transmission history, (2) gears and bearings in transmission, (3) sliding-gear transmissions, (4) planetary gearing, and (5) glossary. The working principles of the sliding-gear transmission, the most…

  6. Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Fink, S.; Rogers, J.; Porter, K.

    2010-07-01

    This report describes transmission cost allocation methodologies for transmission projects developed to maintain or enhance reliability, to interconnect new generators, or to access new resources and enhance competitive bulk power markets, otherwise known as economic transmission projects.

  7. Vaccination with Altered Peptide Ligands of a Plasmodium berghei Circumsporozoite Protein CD8 T-Cell Epitope: A Model to Generate T Cells Resistant to Immune Interference by Polymorphic Epitopes

    Science.gov (United States)

    Minigo, Gabriela; Flanagan, Katie L.; Slattery, Robyn M.; Plebanski, Magdalena

    2017-01-01

    Many pathogens, including the malaria parasite Plasmodium falciparum, display high levels of polymorphism within T-cell epitope regions of proteins associated with protective immunity. The T-cell epitope variants are often non-cross-reactive. Herein, we show in a murine model, which modifies a protective CD8 T-cell epitope from the circumsporozoite protein (CS) of Plasmodium berghei (SYIPSAEKI), that simultaneous or sequential co-stimulation with two of its putative similarly non-cross-reactive altered peptide ligand (APL) epitopes (SYIPSAEDI or SYIPSAEAI) has radically different effects on immunity. Hence, co-immunization or sequential stimulation in vivo of SYIPSAEKI with its APL antagonist SYIPSAEDI decreases immunity to both epitopes. By contrast, co-immunization with SYIPSAEAI has no apparent initial effect, but it renders the immune response to SYIPSAEKI resistant to being turned off by subsequent immunization with SYIPSAEDI. These results suggest a novel strategy for vaccines that target polymorphic epitopes potentially capable of mutual immune interference in the field, by initiating an immune response by co-immunization with the desired index epitope, together with a carefully selected “potentiator” APL peptide.

  8. Antimalarial and hepatoprotective effects of crude ethanolic extract of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.)P.Karst. (higher Basidiomycetes), in Plasmodium berghei-infected mice.

    Science.gov (United States)

    Oluba, Olarewaju M; Olusola, Augustine O; Fagbohunka, Bamidele S; Onyeneke, E

    2012-01-01

    This study was aimed at investigating the in vivo antimalarial activity (using some biochemical indices) of crude aqueous extracts of the fruiting bodies of Ganoderma lucidum, a mushroom with well-established medicinal properties. A rodent malaria parasite, Plasmodium berghei (1 × 107), was inoculated intraperitoneally into Swiss albino mice. The test groups were administered G. lucidum extract and chloroquine (CQ, as standard drug), while the control groups were administered the same amount of distilled water by an intragastric tube once daily. The antimalarial activity of the extract was investigated from the suppressive, curative, and prophylactic effects of the extract on parasite growth. Serum aminotransferases (AST and ALT), alkaline phosphatase (ALP), and gamma glutamine transpeptidase (γ-GT) levels monitored following the 4-day suppressive test were significantly reduced, with a corresponding significant increase in the livers of mice treated with the extract compared with infected untreated mice. The results obtained from this study provide scientific justification in an animal model of malaria that an ethanolic extract of G. lucidum possesses potent antimalarial activity and also could help ameliorate the attendant Plasmodium-induced liver damage due to malarial infection.

  9. Transmissions in vehicles 2010

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Within the international VDI congress 'Gears in vehicles 2010' of the VDI Wissensforum GmbH (Duesseldorf, Federal Republic of Germany) between 22nd and 23rd June, 2010, in Friedrichshafen (Federal Republic of Germany), the following lectures were held: (1) 8HP70H - The moldhybrid transmission from ZF - Cjallenges and achievements (P. Gutmann); (2) GETRAG boosted range extender - A highly flexible electric powertrain for maximum CO{sub 2} reduction (S. Huepkes); (3) E-Transmission between full-hybrid and E-drive (P. Tenberge); (4) Reducing NO{sub x} and particulate emissions in electrified drivelines (R. Kuberczyk); (5) Simulation aided HEV and EV development: from the component to the whole powertrain (A. Gacometti); (6) Investigations on operating behaviour of the optimized CVT hybrid driveline (B.-R. Hoehn); (7) Customer-oriented dimensioning of electrified drivetrains (M. Eghtessad); (8) Decentralized optimal control strategy for parallel hybrid electric vehicles (A. Frenkel); (9) The new generation 6-speed automatic transmission AF40 (G. Bednarek); (10) Customized mechatronic solutions for integrated transmission control units (M. Wieczorek); (11) The optimal automatic transmission for front-transverse applications - Planetary transmissions or dual clutch transmissions? (G. Gumpoltsberger); (12) The new shift-by-wire gearshift lever for the Audi A8 - Requirements and concept (T. Guttenbergere); (13) The new shift-by-wire gearshift lever for the Audi A8 - Realization (A. Giefer); (14) Fuel-efficient transmissions of the future: Calculation of the efficiency factor for vehicle transmissions (B. Volpert); (15) HT-ACM: A new polymer generation for static and dynamic gearbox sealing solutions (E. Osen); (16) 'Energy efficiency equipped solutions by SKF' for power train applications - A contribution to CO{sub 2} - emission reduction and sustainability (T. Bobke); (17) 6-Ratio planetary shift transmission controlled by 4 external brakes, and design

  10. Watching Handball Transmissions

    DEFF Research Database (Denmark)

    Frandsen, Kirsten

    2010-01-01

    , due to the dramaturgic structure of handball transmissions, viewers consider such transmissions particularly reliable and effective sources of entertainment. The transmissions’ entertainment value derives from their specific ability to give the viewers a complex experience of feeling autonomous...... and competent when mastering the game and in relation to others. The study shows that entertainment concerns both affective involvement and identity formation, as social and cultural meaning seem to be at the root of involvement. Even though both men and women find great joy in the transmissions, their viewing...... is embedded in quite diverse patterns regarding additional media use. This points to gendered differences regarding how the entertaining experience is basically received and the qualities sought and pursued in the transmissions....

  11. Down hole transmission system

    Science.gov (United States)

    Hall, David R.; Hall, Jr., H. Tracy

    2007-07-24

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. The electrically conducting coil comprises at least two generally fractional loops. In the preferred embodiment, the transmission elements are connected by an electrical conductor. Preferably, the electrical conductor is a coaxial cable. Preferably, the MCEI trough comprises ferrite. In the preferred embodiment, the fractional loops are connected by a connecting cable. In one aspect of the present invention, the connecting cable is a pair of twisted wires. In one embodiment the connecting cable is a shielded pair of twisted wires. In another aspect of the present invention, the connecting cable is a coaxial cable. The connecting cable may be disposed outside of the MCEI circular trough.

  12. Transmission of Mumps

    Science.gov (United States)

    ... Serology Publications and Resources Multimedia MMWR Articles Outbreak Articles Related Links World Health Organization Medline Plus Transmission of Mumps Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir ...

  13. Kansas Electric Transmission Lines

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set is a digital representation of the EletcircTransmission lines for the State of Kansas as maintained by the Kansas Corporation Commission. Data is...

  14. Eliminating Perinatal HIV Transmission

    Centers for Disease Control (CDC) Podcasts

    2012-11-26

    In this podcast, CDC’s Dr. Steve Nesheim discusses perinatal HIV transmission, including the importance of preventing HIV among women, preconception care, and timely HIV testing of the mother. Dr. Nesheim also introduces the revised curriculum Eliminating Perinatal HIV Transmission intended for faculty of OB/GYN and pediatric residents and nurse midwifery students.  Created: 11/26/2012 by Division of HIV/AIDS Prevention.   Date Released: 11/26/2012.

  15. 77 FR 6554 - Zephyr Power Transmission, LLC; Pathfinder Power Transmission, LLC; Duke-American Transmission...

    Science.gov (United States)

    2012-02-08

    ... Energy Regulatory Commission Zephyr Power Transmission, LLC; Pathfinder Power Transmission, LLC; Duke... (Commission), 18 CFR 381.302, Zephyr Power Transmission, LLC (Zephyr), Pathfinder Power Transmission, LLC (PPT... to exercise its negotiated rate authority for Zephyr Power Transmission Project; (2) that...

  16. National transmission grid study

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Spencer [USDOE Office of the Secretary of Energy, Washington, DC (United States)

    2003-05-31

    The National Energy Policy Plan directed the U.S. Department of Energy (DOE) to conduct a study to examine the benefits of establishing a national electricity transmission grid and to identify transmission bottlenecks and measures to address them. DOE began by conducting an independent analysis of U.S. electricity markets and identifying transmission system bottlenecks using DOE’s Policy Office Electricity Modeling System (POEMS). DOE’s analysis, presented in Section 2, confirms the central role of the nation’s transmission system in lowering costs to consumers through increased trade. More importantly, DOE’s analysis also confirms the results of previous studies, which show that transmission bottlenecks and related transmission system market practices are adding hundreds of millions of dollars to consumers’ electricity bills each year. A more detailed technical overview of the use of POEMS is provided in Appendix A. DOE led an extensive, open, public input process and heard a wide range of comments and recommendations that have all been considered.1 More than 150 participants registered for three public workshops held in Detroit, MI (September 24, 2001); Atlanta, GA (September 26, 2001); and Phoenix, AZ (September 28, 2001).

  17. Geographical structure of dengue transmission and its determinants in Thailand.

    Science.gov (United States)

    Nagao, Y; Svasti, P; Tawatsin, A; Thavara, U

    2008-06-01

    Expansion of dengue has been attributed to urbanization. To test this concept, we examined dengue transmission intensities in Thailand. We used the inverse of mean age of dengue haemorrhagic fever (DHF) cases as a surrogate of dengue transmission intensity (or force of infection). The transmission intensity in Bangkok decreased rapidly since the mid-1990s, to levels that are currently lower than in other regions. Regression analysis revealed that transmission intensity is highest in the Northeastern rural region, mainly due to scarcity of private water wells. Private wells reduce the need for household water containers, the major breeding sites for vectors. Cumulatively, these results show that urbanization is not necessarily associated with intense dengue transmission in Thailand. Paradoxically, the DHF incidence in Bangkok has surpassed other regions despite declines in transmission intensity. This finding implies the existence of endemic stability (i.e. low incidence of a clinical illness in spite of high transmission intensity).

  18. Ultrahigh Transmission Optical Nanofibers

    CERN Document Server

    Hoffman, J E; Grover, J A; Solano, P; Kordell, P R; Wong-Campos, J D; Orozco, L A; Rolston, S L

    2014-01-01

    We present a procedure for reproducibly fabricating ultrahigh transmission optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode transmissions of 99.95 $ \\pm$ 0.02%, which represents a loss from tapering of 2.6 $\\,\\times \\,$ 10$^{-5}$ dB/mm when normalized to the entire stretch. When controllably launching the next family of higher-order modes on a fiber with 195 mm stretch, we achieve a transmission of 97.8 $\\pm$ 2.8%, which has a loss from tapering of 5.0 $\\,\\times \\,$ 10$^{-4}$ dB/mm when normalized to the entire stretch. Our pulling and transfer procedures allow us to fabricate optical nanofibers that transmit more than 400 mW in high vacuum conditions. These results, published as parameters in our previous work, present an improvement of two orders of magnitude less loss for the fundamental mode and an increase in transmission of more than 300% for higher-order modes, when following the protocols detailed in this paper. We extract from the transmission during the pull, the only reported...

  19. Plasmon cross transmission

    Energy Technology Data Exchange (ETDEWEB)

    Dobrzynski, Leonard; Akjouj, Abdellatif; Li, Changsheng, E-mail: Abdellatif.Akjouj@univ-lille1.fr [Centre National de la Recherche Scientifique, Universite Lille Nord de France, Lille1, Institut d' Electronique, de Microelectronique et de Nanotechnologie, Unite de Physique, Batiment P5, 59655 Villeneuve d' Ascq Cedex (France)

    2011-09-14

    Plasmon cross transmission avoids the frontal collision between two plasmons traveling in opposite directions along a guide. The guide is made out of equidistant identical metal dots. Thanks to two resonator dots, the plasmon frontal impact is avoided by transmission of the two plasmons from the input guide to an output one. The resonator and guide dots are identical in size and metal composition. The dipole-dipole interactions are restricted to first nearest neighbors. A convenient metal doping is assumed to compensate exactly all attenuations. The parameters are the nearest neighbor distances between the dots. These distances are rescaled to the chain nearest neighbor distance d. The system has two symmetry mirror planes. This simple model enables us to obtain two analytic tuning relations for the plasmon cross transmission. The intensities of the transmitted signals versus kd, where k is the plasmon propagation vector, are also given. (paper)

  20. Aerosol Transmission of Filoviruses

    Directory of Open Access Journals (Sweden)

    Berhanu Mekibib

    2016-05-01

    Full Text Available Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire and Sudan, the 2013–2015 western African Ebola virus disease (EVD outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses.

  1. Transmission grid security

    CERN Document Server

    Haarla, Liisa; Hirvonen, Ritva; Labeau, Pierre-Etienne

    2011-01-01

    In response to the growing importance of power system security and reliability, ""Transmission Grid Security"" proposes a systematic and probabilistic approach for transmission grid security analysis. The analysis presented uses probabilistic safety assessment (PSA) and takes into account the power system dynamics after severe faults. In the method shown in this book the power system states (stable, not stable, system breakdown, etc.) are connected with the substation reliability model. In this way it is possible to: estimate the system-wide consequences of grid faults; identify a chain of eve

  2. DATA TRANSMISSION INVESTIGATION

    Science.gov (United States)

    modem will have the capability of 18 bit rates and will be used in the investigation of the short range HF data transmission. System block diagrams of...Field test results of various modems operating over the AN/VRC-12 radio set are presented. Map profiles of each data link are shown and the average...error rates are given for digital data transmission at rates from 300 to 4800 bps. Bit error rates vary depending upon the site and bit rate. The

  3. Transmission positron microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Doyama, Masao [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan)]. E-mail: doyama@ntu.ac.jp; Kogure, Yoshiaki [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan); Inoue, Miyoshi [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan); Kurihara, Toshikazu [Institute of Materials Structure Science (IMSS), High Energy Accelerator, Research Organization (KEK), Ohno 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Yoshiie, Toshimasa [Reactor Research Institute, Kyoto University, Noda, Kumatori, Osaka 590-0451 (Japan); Oshima, Ryuichiro [Research Institute for Advanced Science and Technology, Osaka Prefecture University (Japan); Matsuya, Miyuki [Electron Optics Laboratory (JEOL) Ltd., Musashino 3-1-2, Akishima 196-0021 (Japan)

    2006-02-28

    Immediate and near-future plans for transmission positron microscopes being built at KEK, Tsukuba, Japan, are described. The characteristic feature of this project is remolding a commercial electron microscope to a positron microscope. A point source of electrons kept at a negative high voltage is changed to a point source of positrons kept at a high positive voltage. Positional resolution of transmission microscopes should be theoretically the same as electron microscopes. Positron microscopes utilizing trapping of positrons have always positional ambiguity due to the diffusion of positrons.

  4. Montanide, Poly I:C and nanoparticle based vaccines promote differential suppressor and effector cell expansion: a study of induction of CD8 T cells to a minimal Plasmodium berghei epitope

    Directory of Open Access Journals (Sweden)

    Kirsty Lee Wilson

    2015-02-01

    Full Text Available The development of practical and flexible vaccines to target liver stage malaria parasites would benefit from an ability to induce high levels of CD8 T cells to minimal peptide epitopes. Herein we compare different adjuvant and carrier systems in a murine model for induction of interferon gamma (IFN-γ producing CD8 T cells to the minimal immuno-dominant peptide epitope from the circumsporozoite protein (CSP of Plasmodium berghei, pb9 (SYIPSAEKI, referred to as KI. Two pro-inflammatory adjuvants, Montanide and Poly I:C, and a non-classical, non-inflammatory nanoparticle based carrier (polystyrene nanoparticles, PSNPs, were compared side-by-side for their ability to induce potentially protective CD8 T cell responses after two immunisations. KI in Montanide (Montanide + KI or covalently conjugated to PSNPs (PSNPs-KI induced such high responses, whereas adjuvanting with Poly I:C or PSNPs without conjugation was ineffective. This result was consistent with an observed induction of an immunosuppressed environment by Poly I:C in the draining lymph node (dLN 48 hours post injection, which was reflected by increased frequencies of myeloid derived suppressor cells (MDSC and a proportion of inflammation reactive regulatory T cells (Treg expressing the tumour necrosis factor receptor 2 (TNFR2, as well as decreased dendritic cell (DC maturation. The other inflammatory adjuvant, Montanide, also promoted proportional increases in the TNFR2+ Treg subpopulation, but not MDSCs, in the dLN. By contrast, injection with non-inflammatory PSNPs did not cause these changes. Induction of high CD8 T cell responses, using minimal peptide epitopes, can be achieved by non-inflammatory carrier nanoparticles, which in contrast to some conventional inflammatory adjuvants, do not expand either MDSCs or inflammation reactive Tregs at the site of priming.

  5. Dilemmas of Cultural Transmission

    Science.gov (United States)

    Kováts-Németh, Mária

    2016-01-01

    The fundamental problem of the 21st century is that in the modern civilization "the transmission of values is not stable." There is nothing, except for the natural sense of justice and some legal traditions, which would exercise selective power on social behavior. At a critical time in 1949 Albert Szent-Györgyi drew the attention to the…

  6. Facsimile Transmission Standards

    Science.gov (United States)

    1993-10-01

    transmettre les cartes tactiques et les compte rendu de situation. La presente note technique expose les 6lements nec~ssaires A la transmission de t~l6copies...Group MI machines introduced digital scanning techniques in which the single photoelectric cell was replaced with a Charged Coupled Device (CCD) array

  7. Laser power transmission

    Science.gov (United States)

    Conway, Edmund J.

    1992-01-01

    An overview of previous studies related to laser power transmission is presented. Particular attention is given to the use of solar pumped lasers for space power applications. Three general laser mechanisms are addressed: photodissociation lasing driven by sunlight, photoexcitation lasing driven directly by sunlight, and photoexcitation lasing driven by thermal radiation.

  8. Unraveling the Transmission Ecology of Polio.

    Directory of Open Access Journals (Sweden)

    Micaela Martinez-Bakker

    2015-06-01

    Full Text Available Sustained and coordinated vaccination efforts have brought polio eradication within reach. Anticipating the eradication of wild poliovirus (WPV and the subsequent challenges in preventing its re-emergence, we look to the past to identify why polio rose to epidemic levels in the mid-20th century, and how WPV persisted over large geographic scales. We analyzed an extensive epidemiological dataset, spanning the 1930s to the 1950s and spatially replicated across each state in the United States, to glean insight into the drivers of polio's historical expansion and the ecological mode of its persistence prior to vaccine introduction. We document a latitudinal gradient in polio's seasonality. Additionally, we fitted and validated mechanistic transmission models to data from each US state independently. The fitted models revealed that: (1 polio persistence was the product of a dynamic mosaic of source and sink populations; (2 geographic heterogeneity of seasonal transmission conditions account for the latitudinal structure of polio epidemics; (3 contrary to the prevailing "disease of development" hypothesis, our analyses demonstrate that polio's historical expansion was straightforwardly explained by demographic trends rather than improvements in sanitation and hygiene; and (4 the absence of clinical disease is not a reliable indicator of polio transmission, because widespread polio transmission was likely in the multiyear absence of clinical disease. As the world edges closer to global polio eradication and continues the strategic withdrawal of the Oral Polio Vaccine (OPV, the regular identification of, and rapid response to, these silent chains of transmission is of the utmost importance.

  9. Unraveling the Transmission Ecology of Polio.

    Science.gov (United States)

    Martinez-Bakker, Micaela; King, Aaron A; Rohani, Pejman

    2015-06-01

    Sustained and coordinated vaccination efforts have brought polio eradication within reach. Anticipating the eradication of wild poliovirus (WPV) and the subsequent challenges in preventing its re-emergence, we look to the past to identify why polio rose to epidemic levels in the mid-20th century, and how WPV persisted over large geographic scales. We analyzed an extensive epidemiological dataset, spanning the 1930s to the 1950s and spatially replicated across each state in the United States, to glean insight into the drivers of polio's historical expansion and the ecological mode of its persistence prior to vaccine introduction. We document a latitudinal gradient in polio's seasonality. Additionally, we fitted and validated mechanistic transmission models to data from each US state independently. The fitted models revealed that: (1) polio persistence was the product of a dynamic mosaic of source and sink populations; (2) geographic heterogeneity of seasonal transmission conditions account for the latitudinal structure of polio epidemics; (3) contrary to the prevailing "disease of development" hypothesis, our analyses demonstrate that polio's historical expansion was straightforwardly explained by demographic trends rather than improvements in sanitation and hygiene; and (4) the absence of clinical disease is not a reliable indicator of polio transmission, because widespread polio transmission was likely in the multiyear absence of clinical disease. As the world edges closer to global polio eradication and continues the strategic withdrawal of the Oral Polio Vaccine (OPV), the regular identification of, and rapid response to, these silent chains of transmission is of the utmost importance.

  10. Central cholinesterase inhibition enhances glutamatergic synaptic transmission.

    Science.gov (United States)

    Kozhemyakin, Maxim; Rajasekaran, Karthik; Kapur, Jaideep

    2010-04-01

    Central cholinergic overstimulation results in prolonged seizures of status epilepticus in humans and experimental animals. Cellular mechanisms of underlying seizures caused by cholinergic stimulation remain uncertain, but enhanced glutamatergic transmission is a potential mechanism. Paraoxon, an organophosphate cholinesterase inhibitor, enhanced glutamatergic transmission on hippocampal granule cells synapses by increasing the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) in a concentration-dependent fashion. The amplitude of mEPSCs was not increased, which suggested the possibility of enhanced action potential-dependent release. Analysis of EPSCs evoked by minimal stimulation revealed reduced failures and increased amplitude of evoked responses. The ratio of amplitudes of EPSCs evoked by paired stimuli was also altered. The effect of paraoxon on glutamatergic transmission was blocked by the muscarinic antagonist atropine and partially mimicked by carbachol. The nicotinic receptor antagonist α -bungarotoxin did not block the effects of paraoxon; however, nicotine enhanced glutamatergic transmission. These studies suggested that cholinergic overstimulation enhances glutamatergic transmission by enhancing neurotransmitter release from presynaptic terminals.

  11. Droplets and modes of respiratory disease transmission

    Science.gov (United States)

    Bourouiba, Lydia

    2014-11-01

    Direct observation of violent expirations such as sneezes and coughs events reveal that such flows are multiphase turbulent buoyant clouds with suspended droplets of various sizes. The effects of ambient conditions indoors, such as moisture and temperature, coupled with the water content of such clouds are key in shaping the pathogen footprint emitted by potentially sick individuals. Such pathogen footprint can change the patterns of respiratory disease transmission. We discuss how the fluid dynamics of violent expirations can help inform how.

  12. Resonant Transmission Line Method for Econophysics models

    CERN Document Server

    Raptis, T E

    2016-01-01

    In a recent paper [1304.6846], Racorean introduced a formal similarity of the Black-Sholes stock pricing model with a Schr\\"odinger equation. We use a previously introduced method of a resonant transmission line for arbitrary 2nd order Sturm-Liouville problems to attack the same problem from a different perspective revealing some deep structures in the naturally associated eigenvalue problem.

  13. Regional transmission subsystem planning

    Energy Technology Data Exchange (ETDEWEB)

    Costa Bortoni, Edson da [Quadrante Softwares Especializados Ltda., Itajuba, MG (Brazil); Bajay, Sergio Valdir; Barros Correia, Paulo de [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica; Santos, Afonso Henriques Moreira; Haddad, Jamil [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    This work presents an approach for the planning of transmission systems by employing mixed--integer linear programming to obtain a cost and operating characteristics optimized system. The voltage loop equations are written in a modified form, so that, at the end of the analysis, the model behaves as a DC power flow, with the help of the two Kirchhoff`s laws, exempting the need of interaction with an external power flow program for analysis of the line loading. The model considers the occurrence of contingencies, so that the final result is a network robust to the most severe contingencies. This whole technique is adapted to the regional electric power transmission subsystems. (author) 9 refs., 4 figs.

  14. Mechanisms, Transmissions and Applications

    CERN Document Server

    Corves, Burkhard

    2012-01-01

    The first Workshop on Mechanisms, Transmissions and Applications -- MeTrApp-2011 was organized by the Mechatronics Department at the Mechanical Engineering Faculty, “Politehnica” University of Timisoara, Romania, under the patronage of the IFToMM Technical Committees Linkages and Mechanical Controls and Micromachines. The workshop brought together researchers and students who work in disciplines associated with mechanisms science and offered a great opportunity for scientists from all over the world to present their achievements, exchange innovative ideas and create solid international links, setting the trend for future developments in this important and creative field. The topics treated in this volume are mechanisms and machine design, mechanical transmissions, mechatronic and biomechanic applications, computational and experimental methods, history of mechanism and machine science and teaching methods.

  15. Available transmission capacity assessment

    Directory of Open Access Journals (Sweden)

    Škokljev Ivan

    2012-01-01

    Full Text Available Effective power system operation requires the analysis of vast amounts of information. Power market activities expose power transmission networks to high-level power transactions that threaten normal, secure operation of the power system. When there are service requests for a specific sink/source pair in a transmission system, the transmission system operator (TSO must allocate the available transfer capacity (ATC. It is common that ATC has a single numerical value. Additionally, the ATC must be calculated for the base case configuration of the system, while generation dispatch and topology remain unchanged during the calculation. Posting ATC on the internet should benefit prospective users by aiding them in formulating their requests. However, a single numerical value of ATC offers little for prospect for analysis, planning, what-if combinations, etc. A symbolic approach to the power flow problem (DC power flow and ATC offers a numerical computation at the very end, whilst the calculation beforehand is performed by using symbols for the general topology of the electrical network. Qualitative analysis of the ATC using only qualitative values, such as increase, decrease or no change, offers some new insights into ATC evaluation, multiple transactions evaluation, value of counter-flows and their impact etc. Symbolic analysis in this paper is performed after the execution of the linear, symbolic DC power flow. As control variables, the mathematical model comprises linear security constraints, ATC, PTDFs and transactions. The aim is to perform an ATC sensitivity study on a five nodes/seven lines transmission network, used for zonal market activities tests. A relatively complicated environment with twenty possible bilateral transactions is observed.

  16. NB Power Transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, J. [NB Power Transmission, Fredericton, NB (Canada)

    2006-07-01

    The NB Power Transmission System operates 6700 km of transmission lines having voltages of 69 kV, 138 kV, 230 kV, and 345 kV. The history of lightning protection on this transmission system was presented. Lightning protection with shield wires has been applied selectively on the 69 kV and 138 kV lines and has been applied to all lines in the 230 kV and 345 kV range. Beginning in 2000, line arresters were installed on selected 69 kV and 138 kV lines. It was noted that although overhead shield wires are commonly installed to capture lightning strikes and shield the conductors, problems can occur if the electrical flashover of insulators result in a line to ground fault. Good grounding is needed to ensure that lightning enters the ground from the tower. The new approach is to install line arresters on structures without overhead shield wires. Line arresters are surge arresters applied in parallel with the insulator string. This new line arrester technology was tested by installing nearly 1200 arresters in the Saint John area. This paper described the reasons for choosing line arresters over shield wires and presented the methods of installation. The problems and failure rates of the installed line arresters were presented along with solutions, including solutions to protect lines against lightning in areas with heavy icing. Recommendations for future research into the use, application and development of line arresters were also presented. tabs., figs.

  17. Transmission eigenvalues for elliptic operators

    CERN Document Server

    Hitrik, Michael; Ola, Petri; Päivärinta, Lassi

    2010-01-01

    A reduction of the transmission eigenvalue problem for multiplicative sign-definite perturbations of elliptic operators with constant coefficients to an eigenvalue problem for a non-selfadjoint compact operator is given. Sufficient conditions for the existence of transmission eigenvalues and completeness of generalized eigenstates for the transmission eigenvalue problem are derived. In the trace class case, the generic existence of transmission eigenvalues is established.

  18. Cultural transmission of civic attitudes

    OpenAIRE

    Miles-Touya, Daniel; Rossi, Máximo

    2016-01-01

    In this empirical paper we attempt to measure the separate influence on civic engagement of educational attainment and cultural transmission of civic attitudes. Unlike most of the previous empirical works on this issue, we are able to approximate the cultural transmission of civic attitudes. We observe that civic returns to education are overstated when the transmission of civic attitudes is ignored. Moreover, the transmission of civic attitudes significantly enhances civic involvement and re...

  19. Optimizing Transmission Line Matching Circuits

    OpenAIRE

    Novak, S.

    1996-01-01

    When designing transmission line matching circuits, there exist often overlooked, additional, not much used, degree of choice in the selection of the transmission line impedance. In this work are presented results of CAD analysis for the two element transmission line matching networks, demonstrating that selecting matching circuits transmission lines with higher impedance, than usually used 50 or 75 ohms, can in most cases substantially decrease the physical dimension of the final matching ci...

  20. Successes and shortcomings of polio eradication: a transmission modeling analysis.

    Science.gov (United States)

    Mayer, Bryan T; Eisenberg, Joseph N S; Henry, Christopher J; Gomes, M Gabriela M; Ionides, Edward L; Koopman, James S

    2013-06-01

    Polio eradication is on the cusp of success, with only a few regions still maintaining transmission. Improving our understanding of why some regions have been successful and others have not will help with both global eradication of polio and development of more effective vaccination strategies for other pathogens. To examine the past 25 years of eradication efforts, we constructed a transmission model for wild poliovirus that incorporates waning immunity (which affects both infection risk and transmissibility of any resulting infection), age-mediated vaccination rates, and transmission of oral polio vaccine. The model produces results consistent with the 4 country categories defined by the Global Polio Eradication Program: elimination with no subsequent outbreaks; elimination with subsequent transient outbreaks; elimination with subsequent outbreaks and transmission detected for more than 12 months; and endemic polio transmission. Analysis of waning immunity rates and oral polio vaccine transmissibility reveals that higher waning immunity rates make eradication more difficult because of increasing numbers of infectious adults, and that higher oral polio vaccine transmission rates make eradication easier as adults become reimmunized. Given these dynamic properties, attention should be given to intervention strategies that complement childhood vaccination. For example, improvement in sanitation can reduce the reproduction number in problematic regions, and adult vaccination can lower adult transmission.

  1. Effect of benflumetol on DNA content and pH value of the lysosome of Plasmodium berghei%本芴醇对疟原虫DNA含量及溶酶体pH值的影响

    Institute of Scientific and Technical Information of China (English)

    苏瑞斌; 时云林; 李国福; 赵京花

    2001-01-01

    Objective:To study the antimalarial mechanism of benflumetol (B). Methods: Flow cytometry (FCM) was used to analyze the effects of B and chloroquine (CQ) on DNA content of Plasmodium berghei and pH value of the lysosome of malarial parasites. Results: DNA content of the plasmodia not treated with any drugs was not changed in 24 hours,while benflumetol could decrease the DNA content: the DNA content began to decrease 2 h after the drug administration and reached the minimum by 16 h, but somewhat increased at 24 h after administration. The pH in the lysosome increased 1 h and restored premedication level 4 h after benflumetol administration. Chloroquine had the same effects on DNA and lysosome pH of malarial parasites.Conclusions: The antimalarial mechanism of benflumetol is directly related to its effect to inhibit the synthesis of DNA.%目的:探讨本芴醇的抗疟作用机制。方法:采用流式细胞术(FCM)分析了本芴醇和氯喹对鼠伯氏疟原虫K173株DNA含量及溶酶体pH值的影响。结果:对照组疟原虫DNA含量在各时间点没有显著变化。本芴醇单次给药后,随时间推移疟原虫DNA含量逐渐减少,药后2 h两给药组疟原虫红内期 DNA含量开始降低,到16 h降到最低,但药后24 h DNA含量又有所回升。本芴醇单次给药后1 h起疟原虫溶酶体pH值开始升高,药后3 h升至最高,药后4 h原虫溶酶体pH值恢复至药前水平。对照药氯喹对疟原虫DNA含量和溶酶体pH值也有相同影响。结论:本芴醇的抗疟作用与其抑制DNA合成相关,但与其升高溶酶体pH值的关系不明确。

  2. Dynamically prioritized progressive transmission

    Science.gov (United States)

    Blanford, Ronald

    1992-04-01

    Retrieval of image data from a centralized database may be subject to bandwidth limitations, whether due to a low-bandwidth communications link or to contention from simultaneous accesses over a high-bandwidth link. Progressive transmission can alleviate this problem by encoding image data so that any prefix of the data stream approximates the complete image at a coarse level of resolution. The longer the prefix, the finer the resolution. In many cases, as little at 1 percent of the image data may be sufficient to decide whether to discard the image, to permit the retrieval to continue, or to restrict retrieval to a subsection of the image. Our approach treats resolution not as a fixed attribute of the image, but rather as a resource which may be allocated to portions of the image at the direction of a user-specified priority function. The default priority function minimizes error by allocating more resolution to regions of high variance. The user may also point to regions of interest requesting priority transmission. More advanced target recognition strategies may be incorporated at the user's discretion. Multispectral imagery is supported. The user engineering implications are profounded. There is immediate response to a query that might otherwise take minutes to complete. The data is transmitted in small increments so that no single user dominates the communications bandwidth. The user-directed improvement means that bandwidth is focused on interesting information. The user may continue working with the first coarse approximations while further image data is still arriving. The algorithm has been implemented in C on Sun, Silicon Graphics, and NeXT workstations, and in Lisp on a Symbolics. Transmission speeds reach as high as 60,000 baud using a Sparc or 68040 processor when storing data to memory; somewhat less if also updating a graphical display. The memory requirements are roughly five bytes per image pixel. Both computational and memory costs may be reduced

  3. Research and Transmission

    Directory of Open Access Journals (Sweden)

    Denise Pumain

    2001-01-01

    Full Text Available The present situation provides a challenge for us to reconsider the necessary link between science and pedagogy, between research and the transmission of knowledge. The Ministry of National education has just inaugurated a broad consultation of teachers on every level with a view to modernising and giving coherence to the programs of secondary education. Armand Frémont will head the group of experts responsible for history and geography. Is this a coincidence? The changeover in the jury for t...

  4. Conventional transmission electron microscopy.

    Science.gov (United States)

    Winey, Mark; Meehl, Janet B; O'Toole, Eileen T; Giddings, Thomas H

    2014-02-01

    Researchers have used transmission electron microscopy (TEM) to make contributions to cell biology for well over 50 years, and TEM continues to be an important technology in our field. We briefly present for the neophyte the components of a TEM-based study, beginning with sample preparation through imaging of the samples. We point out the limitations of TEM and issues to be considered during experimental design. Advanced electron microscopy techniques are listed as well. Finally, we point potential new users of TEM to resources to help launch their project.

  5. Quantum Contact Transmission

    Institute of Scientific and Technical Information of China (English)

    崔迪

    2015-01-01

    Abstract:Quantum transmission is based on quantum entanglement, which is a kind of the phenomenon of quantum mechanics. Quantum object refers to two or more between the localized, the classic strong correlation. When two object quantum entanglement in the quantum state is not independent, but related, and the correlation distance, a pair of electronic of entanglement state, no matter how far apart, they spin direction will remain an up and a down. If one of the electronic spin direction is changed, another of the electron spin direction wil follow to change immediately.

  6. Transmission Properties of Fiber Probes

    Institute of Scientific and Technical Information of China (English)

    XUE Chun-rong; ZHU Sheng-xiang; XIAO Zhi-gang

    2004-01-01

    Transmission properties of tapered fiber including right cone fiber and bend optical fiber are discussed. The transmission efficiency of the tapered fiber is measured. The curve of transmission efficiency versus taper cone angle is given. By the scalar wave equation and Gaussian approximation, transmission properties of the two kinds of tapered fibers are analyzed, the power losses caused by taper cone angle and by the bending are also calculated. From the experiments and theoretical analysis, it could come to a conclusion that the wider the taper cone angle is, the higher the transmission efficiency will be.

  7. [Oral transmission of Chagas' disease].

    Science.gov (United States)

    Toso M, Alberto; Vial U, Felipe; Galanti, Norbel

    2011-02-01

    The traditional transmission pathways of Chagas' disease are vectorial, transfusional, transplacental and organ transplantation. However, oral transmission is gaining importance. The first evidence of oral transmission was reported in Brazil in 1965. Nowadays the oral route is the transmission mode in 50% of cases in the Amazon river zone. Oral infection is produced by the ingestion of infected triatomine bugs or their feces, undercooked meat from infested host animals and food contaminated with urine or anal secretion of infected marsupials. Therefore travelers to those zones should be advised about care to be taken with ingested food. In Chile, this new mode of transmission should be considered in public health policies.

  8. Broadband transmission EPR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wilfred R Hagen

    Full Text Available EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9-10 GHz range. Most (biomolecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin - nuclear spin interactions and electron spin - electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8-2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed.

  9. Complete polarimetry on the asymmetric transmission through subwavelength hole arrays.

    Science.gov (United States)

    Arteaga, Oriol; Maoz, Ben M; Nichols, Shane; Markovich, Gil; Kahr, Bart

    2014-06-02

    Dissymmetric, periodically nanostructured metal films can show non-reciprocal transmission of polarized light, in apparent violation of the Lorentz reciprocity theorem. The wave vector dependence of the extraordinary optical transmission in gold films with square and oblique subwavelength hole arrays was examined for the full range of polarized light input states. In normal incidence, the oblique lattice, in contrast to square lattice, showed strong asymmetric, non-reciprocal transmission of circularly polarized light. By analyzing the polarization of the input and the output with a complete Mueller matrix polarimeter the mechanisms that permits asymmetric transmission while preserving the requirement of electromagnetic reciprocity is revealed: the coupling of the linear anisotropies induced by misaligned surface plasmons in the film. The square lattice also shows asymmetric transmission at non-normal incidence, whenever the plane of incidence does not coincide with a mirror line.

  10. Testing Transmission Mechanisms on Economic Growth in Malaysia

    OpenAIRE

    Wai Ching Poon

    2010-01-01

    This paper examines various transmission mechanism channels on economic growth in Malaysia over the quarterly period 1980:1-2004:4 using bounds testing approach. The bounds test reveals evidence of cointegration between the real GDP and the real exchange rate and share prices that address the exchange rate and asset price channels as the key transmission mechanisms in the conduct of the monetary policy stance. Nevertheless, the saving interest rate and credit channels are of insignificant.

  11. Resonant Transmission of Narrow Metallic Slit with Imperfect Inner Face

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng; YAN Chang-Chun; LIU Ying; CHEN Hao

    2005-01-01

    @@ We numerically analyse the spectral properties of resonant transmission of light through a sub-wavelength metal slit with imperfect inner face. It is found that slight defects on the inner face of the slit can remarkably increase the spectrum shift of its resonant transmission, and this spectra-shift enhancement can be attributed to the induced evanescent waves by the defects. This finding reveals the relationship between the spectrum shift of resonant transmission and the evanescent waves and is potentially useful to explain some extraordinary phenomena in practical experiments, in which the metallic slit is always not ideally smooth.

  12. Liquid Cell Transmission Electron Microscopy

    Science.gov (United States)

    Liao, Hong-Gang; Zheng, Haimei

    2016-05-01

    Liquid cell transmission electron microscopy (TEM) has attracted significant interest in recent years. With nanofabricated liquid cells, it has been possible to image through liquids using TEM with subnanometer resolution, and many previously unseen materials dynamics have been revealed. Liquid cell TEM has been applied to many areas of research, ranging from chemistry to physics, materials science, and biology. So far, topics of study include nanoparticle growth and assembly, electrochemical deposition and lithiation for batteries, tracking and manipulation of nanoparticles, catalysis, and imaging of biological materials. In this article, we first review the development of liquid cell TEM and then highlight progress in various areas of research. In the study of nanoparticle growth, the electron beam can serve both as the illumination source for imaging and as the input energy for reactions. However, many other research topics require the control of electron beam effects to minimize electron beam damage. We discuss efforts to understand electron beam-liquid matter interactions. Finally, we provide a perspective on future challenges and opportunities in liquid cell TEM.

  13. Stress transmission in soil

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    We urgently need increased quantitative knowledge on stress transmission in real soils loaded with agricultural machinery. 3D measurements of vertical stresses under tracked wheels were performed in situ in a Stagnic Luvisol (clay content 20 %) continuously cropped with small grain cereals......). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil in each of three depths (0.3, 0.6 and 0.9 m), covering the width of the wheeled area. The position of the wheel relative to the transducers was recorded using a laser sensor. Finally, the vertical stresses near...... the soil-tyre interface were measured in separate tests by 17 stress transducers across the width of the tyres. The results showed that the inflation pressure controlled the level of maximum stresses at 0.3 m depth, while the wheel load was correlated to the measured stresses at 0.9 m depth. This supports...

  14. Transmission of Electric Energy Along Long Lines

    Directory of Open Access Journals (Sweden)

    Berzan V.P.

    2009-08-01

    Full Text Available Transmission of electric energy along long lines is examined and characteristics of the change of capacities at the beginning and at the end of a line are submitted: factor of capacity, efficiency of a transmission line, currents depending on length, parameters of a line and parameters of loading. Influence of losses upon the dynamics of instant values of voltages and currents in the opened and short-circuited long lines is investigated and effects of nonlinearity in such chains are revealed at a power supply from a sinusoidal source of voltage. It is shown, that the method of complex amplitudes is not always applicable for the calculation of modes in long lines.

  15. A viral vectored prime-boost immunization regime targeting the malaria Pfs25 antigen induces transmission-blocking activity.

    Directory of Open Access Journals (Sweden)

    Anna L Goodman

    Full Text Available The ookinete surface protein Pfs25 is a macrogamete-to-ookinete/ookinete stage antigen of Plasmodium falciparum, capable of exerting high-level anti-malarial transmission-blocking activity following immunization with recombinant protein-in-adjuvant formulations. Here, this antigen was expressed in recombinant chimpanzee adenovirus 63 (ChAd63, human adenovirus serotype 5 (AdHu5 and modified vaccinia virus Ankara (MVA viral vectored vaccines. Two immunizations were administered to mice in a heterologous prime-boost regime. Immunization of mice with AdHu5 Pfs25 at week 0 and MVA Pfs25 at week 10 (Ad-MVA Pfs25 resulted in high anti-Pfs25 IgG titers, consisting of predominantly isotypes IgG1 and IgG2a. A single priming immunization with ChAd63 Pfs25 was as effective as AdHu5 Pfs25 with respect to ELISA titers at 8 weeks post-immunization. Sera from Ad-MVA Pfs25 immunized mice inhibited the transmission of P. falciparum to the mosquito both ex vivo and in vivo. In a standard membrane-feeding assay using NF54 strain P. falciparum, oocyst intensity in Anopheles stephensi mosquitoes was significantly reduced in an IgG concentration-dependent manner when compared to control feeds (96% reduction of intensity, 78% reduction in prevalence at a 1 in 5 dilution of sera. In addition, an in vivo transmission-blocking effect was also demonstrated by direct feeding of immunized mice infected with Pfs25DR3, a chimeric P. berghei line expressing Pfs25 in place of endogenous Pbs25. In this assay the density of Pfs25DR3 oocysts was significantly reduced when mosquitoes were fed on vaccinated as compared to control mice (67% reduction of intensity, 28% reduction in prevalence and specific IgG titer correlated with efficacy. These data confirm the utility of the adenovirus-MVA vaccine platform for the induction of antibodies with transmission-blocking activity, and support the continued development of this alternative approach to transmission-blocking malaria subunit

  16. International Transmission Under Bretton Woods

    OpenAIRE

    Alan C. Stockman

    1992-01-01

    This paper explores the main channels of international transmission of economic disturbances under the Bretton Woods System and presents evidence on the short-run international transmission of inflation under that system. There appears to have been little short-run international transmission of inflation. Countries with one-percent higher money-growth rates subsequently had one-fourth to one-half percent higher inflation and a (predictably) lower real interest rate. This probably reflects eff...

  17. The interior transmission problem and bounds on transmission eigenvalues

    CERN Document Server

    Hitrik, Michael; Ola, Petri; Päivärinta, Lassi

    2010-01-01

    We study the interior transmission eigenvalue problem for sign-definite multiplicative perturbations of the Laplacian in a bounded domain. We show that all but finitely many complex transmission eigenvalues are confined to a parabolic neighborhood of the positive real axis.

  18. Translational repression of the cpw-wpc gene family in the malaria parasite Plasmodium

    KAUST Repository

    Rao, Pavitra N.

    2016-06-14

    The technical challenges of working with the sexual stages of the malaria parasite Plasmodium have hindered the characterization of sexual stage antigens in the quest for a successful malaria transmission-blocking vaccine. One such predicted and largely uncharacterized group of sexual stage candidate antigens is the CPW-WPC family of proteins. CPW-WPC proteins are named for a characteristic domain that contains two conserved motifs, CPxxW and WPC. Conserved across Apicomplexa, this family is also present earlier in the Alveolata in the free-living, non-parasitophorous, photosynthetic chromerids, Chromera and Vitrella. In P. falciparum and P. berghei blood stage parasites the transcripts of all nine cpw-wpc genes have been detected in gametocytes. RNA immunoprecipitation followed by reverse transcriptase-PCR reveals all P. berghei cpw-wpc transcripts to be bound by the translational repressors DOZI and CITH, and thus are likely under translational control prior to transmission from the rodent host to the mosquito vector in P. berghei. The GFP tagging of two endogenous P. berghei genes confirmed translational silencing in the gametocyte and translation in ookinetes. Establishing a luciferase transgene assay we show that the 3′ untranslated region of PF3D7_1331400 controls protein expression of this reporter in P. falciparum gametocytes. Our analyses suggest that cpw-wpc genes are translationally silenced in gametocytes across Plasmodium spp. and activated during ookinete formation and thus may have a role in transmission to the mosquito.

  19. The Plasmodium falciparum Cell-Traversal Protein for Ookinetes and Sporozoites as a Candidate for Preerythrocytic and Transmission-Blocking Vaccines

    Science.gov (United States)

    Espinosa, Diego A.; Vega-Rodriguez, Joel; Flores-Garcia, Yevel; Noe, Amy R.; Muñoz, Christian; Coleman, Russell; Bruck, Torben; Haney, Keith; Stevens, Alex; Retallack, Diane; Allen, Jeff; Vedvick, Thomas S.; Fox, Christopher B.; Reed, Steven G.; Howard, Randall F.; Salman, Ahmed M.; Janse, Chris J.; Khan, Shahid M.

    2016-01-01

    ABSTRACT Recent studies have shown that immune responses against the cell-traversal protein for Plasmodium ookinetes and sporozoites (CelTOS) can inhibit parasite infection. While these studies provide important evidence toward the development of vaccines targeting this protein, it remains unknown whether these responses could engage the Plasmodium falciparum CelTOS in vivo. Using a newly developed rodent malaria chimeric parasite expressing the P. falciparum CelTOS (PfCelTOS), we evaluated the protective effect of in vivo immune responses elicited by vaccination and assessed the neutralizing capacity of monoclonal antibodies specific against PfCelTOS. Mice immunized with recombinant P. falciparum CelTOS in combination with the glucopyranosyl lipid adjuvant-stable emulsion (GLA-SE) or glucopyranosyl lipid adjuvant-liposome-QS21 (GLA-LSQ) adjuvant system significantly inhibited sporozoite hepatocyte infection. Notably, monoclonal antibodies against PfCelTOS strongly inhibited oocyst development of P. falciparum and Plasmodium berghei expressing PfCelTOS in Anopheles gambiae mosquitoes. Taken together, our results demonstrate that anti-CelTOS responses elicited by vaccination or passive immunization can inhibit sporozoite and ookinete infection and impair vector transmission. PMID:27895131

  20. Acoustic data transmission method

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, A.

    1991-09-17

    This patent describes a method for transmitting time line data through a drillstring having drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints. It comprises generating acoustic data signals having a single frequency content in at least one passband of the drillstring; transmitting the data signals through the drillstring from either the first location to the second location or from the second location to the first location during a time period prior to the onset of reflective interference caused by the data signals reflecting from along the length of the drillstring, the time period being equal to or less than the time for the data signals to travel three lengths of the drillstring; stopping the transmission of data signals at the onset of the reflective interference and allowing the acoustic signals to substantially attenuate; and detecting the data signals at the respective first or second location.

  1. EC Transmission Line Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, Tim S [ORNL

    2012-05-01

    The purpose of this document is to identify materials acceptable for use in the US ITER Project Office (USIPO)-supplied components for the ITER Electron cyclotron Heating and Current Drive (ECH&CD) transmission lines (TL), PBS-52. The source of material property information for design analysis shall be either the applicable structural code or the ITER Material Properties Handbook. In the case of conflict, the ITER Material Properties Handbook shall take precedence. Materials selection, and use, shall follow the guidelines established in the Materials Assessment Report (MAR). Materials exposed to vacuum shall conform to the ITER Vacuum Handbook. [Ref. 2] Commercial materials shall conform to the applicable standard (e.g., ASTM, JIS, DIN) for the definition of their grade, physical, chemical and electrical properties and related testing. All materials for which a suitable certification from the supplier is not available shall be tested to determine the relevant properties, as part of the procurement. A complete traceability of all the materials including welding materials shall be provided. Halogenated materials (example: insulating materials) shall be forbidden in areas served by the detritiation systems. Exceptions must be approved by the Tritium System and Safety Section Responsible Officers.

  2. HVDC power transmission technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hauth, R.L.; Tatro, P.J.; Railing, B.D. [New England Power Service Co., Westborough, MA (United States); Johnson, B.K.; Stewart, J.R. [Power Technologies, Inc., Schenectady, NY (United States); Fink, J.L.

    1997-04-01

    The purpose of this study was to develop an assessment of the national utility system`s needs for electric transmission during the period 1995-2020 that could be met by future reduced-cost HVDC systems. The assessment was to include an economic evaluation of HVDC as a means for meeting those needs as well as a comparison with competing technologies such as ac transmission with and without Flexible AC Transmission System (FACTS) controllers. The role of force commutated dc converters was to be assumed where appropriate. The assessment begins by identifying the general needs for transmission in the U.S. in the context of a future deregulated power industry. The possible roles for direct current transmission are then postulated in terms of representative scenarios. A few of the scenarios are illustrated with the help of actual U.S. system examples. non-traditional applications as well as traditional applications such as long lines and asynchronous interconnections are discussed. The classical ``break-even distance`` concept for comparing HVDC and ac lines is used to assess the selected scenarios. The impact of reduced-cost converters is reflected in terms of the break-even distance. This report presents a comprehensive review of the functional benefits of HVDC transmission and updated cost data for both ac and dc system components. It also provides some provocative thoughts on how direct current transmission might be applied to better utilize and expand our nation`s increasingly stressed transmission assets.

  3. Broadband Transmission and Statistical Performance Properties of Overhead High-Voltage Transmission Networks

    Directory of Open Access Journals (Sweden)

    Athanasios G. Lazaropoulos

    2012-01-01

    Full Text Available This paper considers broadband signal transmission and statistical performance properties of high-voltage/broadband over power lines (HV/BPL channels associated with overhead power transmission. The overhead HV/BPL transmission channel is investigated with regard to its spectral behavior, its end-to-end signal attenuation, and its statistical performance metrics. It is found that the above features depend critically on the frequency, the overhead HV power grid type (150 kV, 275 kV, or 400 kV and single- or double-circuit, the coupling scheme applied, the physical properties of the cables used, the MTL configuration, and the type of branches existing along the end-to-end BPL signal propagation. The contribution of this paper is threefold. First, the significant broadband transmission potential of overhead HV lines is revealed. The results demonstrate that, regardless of overhead HV power grid type, the overhead HV grid is a potentially excellent communications medium, offering low-loss characteristics, flat-fading features, and low multipath dispersion over a 25 km repeater span well beyond 100 MHz. Second, regarding the statistical properties of various overhead HV/BPL transmission channels, two fundamental correlations of several wireline systems, for example, coaxial cables and xDSL, are also validated in the case of overhead HV/BPL transmission channels, namely, (i end-to-end channel attenuation in relation with root-mean-square delay spread (RMS-DS and (ii coherence bandwidth (CB in relation with RMS-DS. Third, fitting the numerical results and other field trial measurements, two regression distributions suitable for each fundamental correlation are proposed.

  4. Regional Transmission Projects: Finding Solutions

    Energy Technology Data Exchange (ETDEWEB)

    The Keystone Center

    2005-06-15

    The Keystone Center convened and facilitated a year-long Dialogue on "Regional Transmission Projects: Finding Solutions" to develop recommendations that will help address the difficult and contentious issues related to expansions of regional electric transmission systems that are needed for reliable and economic transmission of power within and across regions. This effort brought together a cross-section of affected stakeholders and thought leaders to address the problem with the collective wisdom of their experience and interests. Transmission owners sat at the table with consumer advocates and environmental organizations. Representatives from regional transmission organizations exchanged ideas with state and federal regulators. Generation developers explored common interests with public power suppliers. Together, the Dialogue participants developed consensus solutions about how to begin unraveling some of the more intractable issues surrounding identification of need, allocation of costs, and reaching consensus on siting issues that can frustrate the development of regional transmission infrastructure. The recommendations fall into three broad categories: 1. Recommendations on appropriate institutional arrangements and processes for achieving regional consensus on the need for new or expanded transmission infrastructure 2. Recommendations on the process for siting of transmission lines 3. Recommendations on the tools needed to support regional planning, cost allocation, and siting efforts. List of Dialogue participants: List of Dialogue Participants: American Electric Power American Transmission Company American Wind Energy Association California ISO Calpine Corporation Cinergy Edison Electric Institute Environmental Defense Federal Energy Regulatory Commission Great River Energy International Transmission Company ISO-New England Iowa Public Utility Board Kanner & Associates Midwest ISO National Association of Regulatory Utility Commissioners National Association

  5. Energy Transmission and Infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Mathison, Jane

    2012-12-31

    The objective of Energy Transmission and Infrastructure Northern Ohio (OH) was to lay the conceptual and analytical foundation for an energy economy in northern Ohio that will: • improve the efficiency with which energy is used in the residential, commercial, industrial, agricultural, and transportation sectors for Oberlin, Ohio as a district-wide model for Congressional District OH-09; • identify the potential to deploy wind and solar technologies and the most effective configuration for the regional energy system (i.e., the ratio of distributed or centralized power generation); • analyze the potential within the district to utilize farm wastes to produce biofuels; • enhance long-term energy security by identifying ways to deploy local resources and building Ohio-based enterprises; • identify the policy, regulatory, and financial barriers impeding development of a new energy system; and • improve energy infrastructure within Congressional District OH-09. This objective of laying the foundation for a renewable energy system in Ohio was achieved through four primary areas of activity: 1. district-wide energy infrastructure assessments and alternative-energy transmission studies; 2. energy infrastructure improvement projects undertaken by American Municipal Power (AMP) affiliates in the northern Ohio communities of Elmore, Oak Harbor, and Wellington; 3. Oberlin, OH-area energy assessment initiatives; and 4. a district-wide conference held in September 2011 to disseminate year-one findings. The grant supported 17 research studies by leading energy, policy, and financial specialists, including studies on: current energy use in the district and the Oberlin area; regional potential for energy generation from renewable sources such as solar power, wind, and farm-waste; energy and transportation strategies for transitioning the City of Oberlin entirely to renewable resources and considering pedestrians, bicyclists, and public transportation as well as drivers

  6. Propagation of microwaves in gradient transmission lines: exactly solvable model

    Science.gov (United States)

    Shvartsburg, A. B.; Silin, N. V.

    2015-08-01

    Propagation of microwaves along the transmission line with smoothly continuously distributed capacitance and inductance (gradient transmission line) is considered in the framework of an exactly solvable model. The appearance of strong heterogeneity-induced plasma-like dispersion in gradient transmission line determined by the sizes and shapes of these distributions, is visualized by means of this model. Owing to this dispersion the energy transport in the line discussed can be ensured by both travelling and evanescent microwave modes, characterized by the real and imaginary wave numbers, respectively. The reflectance spectra for microwaves, incident on this heterogeneous transition section located between two homogeneous sections of transmission line are presented, the antireflection properties of this section are demonstrated. The interference of evanescent and anti-evanescent microwave modes is shown to provide the effective weakly attenuated energy transfer in the tunneling regime. The analogy between this microwave system and gradient nano-optical photonic barrier in revealed.

  7. Sensitivity analysis of the age-structured malaria transmission model

    Science.gov (United States)

    Addawe, Joel M.; Lope, Jose Ernie C.

    2012-09-01

    We propose an age-structured malaria transmission model and perform sensitivity analyses to determine the relative importance of model parameters to disease transmission. We subdivide the human population into two: preschool humans (below 5 years) and the rest of the human population (above 5 years). We then consider two sets of baseline parameters, one for areas of high transmission and the other for areas of low transmission. We compute the sensitivity indices of the reproductive number and the endemic equilibrium point with respect to the two sets of baseline parameters. Our simulations reveal that in areas of either high or low transmission, the reproductive number is most sensitive to the number of bites by a female mosquito on the rest of the human population. For areas of low transmission, we find that the equilibrium proportion of infectious pre-school humans is most sensitive to the number of bites by a female mosquito. For the rest of the human population it is most sensitive to the rate of acquiring temporary immunity. In areas of high transmission, the equilibrium proportion of infectious pre-school humans and the rest of the human population are both most sensitive to the birth rate of humans. This suggests that strategies that target the mosquito biting rate on pre-school humans and those that shortens the time in acquiring immunity can be successful in preventing the spread of malaria.

  8. The evolution of transmission mode

    Science.gov (United States)

    Forbes, Mark R.; Hauffe, Heidi C.; Kallio, Eva R.; Okamura, Beth; Sait, Steven M.

    2017-01-01

    This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phylogenetic studies, including changes in transmission associated with host shifts and with evolution of the unusually complex life cycles of many parasites. Understanding the forces that determine the evolution of particular transmission modes presents a fascinating medley of problems for which there is a lack of good data and often a lack of conceptual understanding or appropriate methodologies. Our best information comes from studies that have been focused on the vertical versus horizontal transmission dichotomy. With other kinds of transitions, theoretical approaches combining epidemiology and population genetics are providing guidelines for determining when and how rapidly new transmission modes may evolve, but these are still in need of empirical investigation and application to particular cases. Obtaining such knowledge is a matter of urgency in relation to extant disease threats. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289251

  9. Lrp4 in astrocytes modulates glutamatergic transmission.

    Science.gov (United States)

    Sun, Xiang-Dong; Li, Lei; Liu, Fang; Huang, Zhi-Hui; Bean, Jonathan C; Jiao, Hui-Feng; Barik, Arnab; Kim, Seon-Myung; Wu, Haitao; Shen, Chengyong; Tian, Yun; Lin, Thiri W; Bates, Ryan; Sathyamurthy, Anupama; Chen, Yong-Jun; Yin, Dong-Min; Xiong, Lei; Lin, Hui-Ping; Hu, Jin-Xia; Li, Bao-Ming; Gao, Tian-Ming; Xiong, Wen-Cheng; Mei, Lin

    2016-08-01

    Neurotransmission requires precise control of neurotransmitter release from axon terminals. This process is regulated by glial cells; however, the underlying mechanisms are not fully understood. We found that glutamate release in the brain was impaired in mice lacking low-density lipoprotein receptor-related protein 4 (Lrp4), a protein that is critical for neuromuscular junction formation. Electrophysiological studies revealed compromised release probability in astrocyte-specific Lrp4 knockout mice. Lrp4 mutant astrocytes suppressed glutamatergic transmission by enhancing the release of ATP, whose level was elevated in the hippocampus of Lrp4 mutant mice. Consequently, the mutant mice were impaired in locomotor activity and spatial memory and were resistant to seizure induction. These impairments could be ameliorated by blocking the adenosine A1 receptor. The results reveal a critical role for Lrp4, in response to agrin, in modulating astrocytic ATP release and synaptic transmission. Our findings provide insight into the interaction between neurons and astrocytes for synaptic homeostasis and/or plasticity.

  10. Load Distribution in Transmissions "Split"

    Science.gov (United States)

    Krantz, Timothy L.; Delgado, Irebert R.

    1998-01-01

    The transmission system of a helicopter must meet particularly critical requirements. It must transmit engine power to the rotor, at the same time ensuring a typical speed reduction of 60 to 1. It must also be safe, reliable, light, and reach a high level of performance while, at the same time, it must produce few vibrations and little noise. Helicopter transmissions have achieved high-level performances thanks to the combination of analyses, experiments, and the application of practical field experience. However, the new generation of helicopters will require transmission systems that are even safer, lighter, less noisy, and more reliable.

  11. Midwest Transmission Workshop I Summary

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Bryan

    2001-05-01

    OAK-B135 The meeting was opened with a review of the purposes of the workshop: (1) Present and discuss key studies and assessments of transmission upgrades, additions and related issues for the upper Midwest, including work that addresses the full range of views on these topics; (2) Understand the various transmission issues in the upper Midwest and discuss options for addressing the issues; and (3) Identify the decision makers and entities that need to play an active role if transmission issues are to be resolved, and agree on next steps for engaging these individuals and organizations through education, outreach, and information dissemination.

  12. Metals on BN Studied by High Resolution Transmission Electron Microscopy

    Science.gov (United States)

    Bangert, U.; Zan, R.; Ramasse, Q.; Jalil, Rashid; Riaz, Ibstam; Novoselov, K. S.

    2012-07-01

    Metal impurities, gold and nickel, have been deliberately introduced into boron-nitride (BN) sheets. The structural and topographic properties of doped BN have been studied by aberration corrected scanning transmission electron microscopy (STEM). Analysis revealed that metal atoms cluster preferentially in/on contaminated areas. The metal coverage on BN is almost the same for the same evaporated amount of 1 Å.

  13. Transmission line model for nanoelectronics

    Directory of Open Access Journals (Sweden)

    Nelin E. A.

    2009-08-01

    Full Text Available Analytical expressions for resonant parametres and characteristics of typical barrier nanoelectronic structures have been received on the basis of the transmission line model. Characteristics illustrating the efficiency of such approach are presented in the article.

  14. Hybrid-Vehicle Transmission System

    Science.gov (United States)

    Lupo, G.; Dotti, G.

    1985-01-01

    Continuously-variable transmission system for hybrid vehicles couples internal-combustion engine and electric motor section, either individually or in parallel, to power vehicle wheels during steering and braking.

  15. Cultural transmission of civic attitudes.

    Science.gov (United States)

    Miles-Touya, Daniel; Rossi, Máximo

    2016-01-01

    In this empirical paper we attempt to measure the separate influence on civic engagement of educational attainment and cultural transmission of civic attitudes. Unlike most of the previous empirical works on this issue, we are able to approximate the cultural transmission of civic attitudes. We observe that civic returns to education are overstated when the transmission of civic attitudes is ignored. Moreover, the transmission of civic attitudes significantly enhances civic involvement and reinforces civic returns to education. Our findings are in line with the proposals of civic virtue theorists or grass movements who suggest that citizenship education should be included in the compulsory school curricula since, if not, families or local communities will only transmit their particular view of the world.

  16. Radio and line transmission 2

    CERN Document Server

    Roddy, Dermot

    2013-01-01

    Radio and Line Transmission, Volume 2 gives a detailed treatment of the subject as well as an introduction to additional advanced subject matter. Organized into 14 chapters, this book begins by explaining the radio wave propagation, signal frequencies, and bandwidth. Subsequent chapters describe the transmission lines and cables; the aerials; tuned and coupled circuits; bipolar transistor amplifiers; field-effect transistors and circuits; thermionic valve amplifiers; LC oscillators; the diode detectors and modulators; and the superheterodyne receiver. Other chapters explore noise and interfere

  17. Advanced Rotorcraft Transmission (ART) program

    Science.gov (United States)

    Heath, Gregory F.; Bossler, Robert B., Jr.

    1993-01-01

    Work performed by the McDonnell Douglas Helicopter Company and Lucas Western, Inc. within the U.S. Army/NASA Advanced Rotorcraft Transmission (ART) Program is summarized. The design of a 5000 horsepower transmission for a next generation advanced attack helicopter is described. Government goals for the program were to define technology and detail design the ART to meet, as a minimum, a weight reduction of 25 percent, an internal noise reduction of 10 dB plus a mean-time-between-removal (MTBR) of 5000 hours compared to a state-of-the-art baseline transmission. The split-torque transmission developed using face gears achieved a 40 percent weight reduction, a 9.6 dB noise reduction and a 5270 hour MTBR in meeting or exceeding the above goals. Aircraft mission performance and cost improvements resulting from installation of the ART would include a 17 to 22 percent improvement in loss-exchange ratio during combat, a 22 percent improvement in mean-time-between-failure, a transmission acquisition cost savings of 23 percent of $165K, per unit, and an average transmission direct operating cost savings of 33 percent, or $24K per flight hour. Face gear tests performed successfully at NASA Lewis are summarized. Also, program results of advanced material tooth scoring tests, single tooth bending tests, Charpy impact energy tests, compact tension fracture toughness tests and tensile strength tests are summarized.

  18. Using Complexity Measure to Characterize Information Transmission of Human Brain Cortex

    Institute of Scientific and Technical Information of China (English)

    徐京华; 吴祥宝

    1994-01-01

    The information transmission among various parts of the cortex are computed with the the-ory of mutual information from the data of the electroencephalogram(EEG)time series of normal humansubjects.The intensities of these transmissions are characterized by the"complexity"measures.These mea-sures have revealed to be sensitively related to the functional conditions of human beings.

  19. Image simulations of kinked vortices for transmission electron microscopy

    DEFF Research Database (Denmark)

    Beleggia, Marco; Pozzi, G.; Tonomura, A.

    2010-01-01

    We present an improved model of kinked vortices in high-Tc superconductors suitable for the interpretation of Fresnel or holographic observations carried out with a transmission electron microscope. A kinked vortex is composed of two displaced half-vortices, perpendicular to the film plane...... observations of high-Tc superconducting films, where the Fresnel contrast associated with some vortices showed a dumbbell like appearance. Here, we show that under suitable conditions the JV segment may reveal itself in Fresnel imaging or holographic phase mapping in a transmission electron microscope....

  20. Transmission Electron Microscopy Characterization of Helium Bubbles in Aged Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, A J; Wall, M A; Zocco, T G; Blobaum, K M

    2004-11-02

    The self-irradiation damage generated by alpha decay of plutonium results in the formation of lattice defects, helium, and uranium atoms. Over time, microstructural evolution resulting from the self-irradiation may influence the physical and mechanical properties of the material. In order to assess microstructural changes, we have developed and applied procedures for the specimen preparation, handling, and transmission electron microscopy characterization of Pu alloys. These transmission electron microscopy investigations of Pu-Ga alloys ranging in age up to 42-years old reveal the presence of nanometer-sized helium bubbles. The number density of bubbles and the average size have been determined for eight different aged materials.

  1. Clustering, climate and dengue transmission.

    Science.gov (United States)

    Junxiong, Pang; Yee-Sin, Leo

    2015-06-01

    Dengue is currently the most rapidly spreading vector-borne disease, with an increasing burden over recent decades. Currently, neither a licensed vaccine nor an effective anti-viral therapy is available, and treatment largely remains supportive. Current vector control strategies to prevent and reduce dengue transmission are neither efficient nor sustainable as long-term interventions. Increased globalization and climate change have been reported to influence dengue transmission. In this article, we reviewed the non-climatic and climatic risk factors which facilitate dengue transmission. Sustainable and effective interventions to reduce the increasing threat from dengue would require the integration of these risk factors into current and future prevention strategies, including dengue vaccination, as well as the continuous support and commitment from the political and environmental stakeholders.

  2. Harmonics in transmission power systems

    DEFF Research Database (Denmark)

    Wiechowski, Wojciech Tomasz

    in transmission power systems" was formulated. In this project, the entire 400 kV and 150 kV western transmission network of Energinet.dk is modelled using the simulation software DIgSILENT PowerFactory. A fundamental frequency load-flow model is used as a basis that is to be extended. The model is sought......, provided that background harmonic distortion, and the network configuration, are not changing during the measurement. It is shown that switching of a shunt linear power system component can result in variation of the harmonic levels that can be measured and used to verify the harmonic model of the network......, in order to determine which power system component, when switched, results in the largest change in harmonic levels, some initial harmonic simulations, using the created harmonic model of Energinet.dk transmission network, are performed. The criterion is that the measuring equipment shall not be installed...

  3. Midwest Transmission Workshop III Summary

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Bryan

    2003-03-12

    OAK-B135 On March 12-13, 2002, the National Wind Coordinating Committee (NWCC), in cooperation with regional stakeholders, held a two-day workshop: Planning for Electrical Transmission Needs in the Upper Midwest. The workshop was the outgrowth of an effort to develop a forum and process for consideration of transmission options that strives for equitable allocation of benefits and impacts among all affected parties. The goal of this workshop was to provide a catalyst for an enhanced, inclusive process for transmission planning with participation of and acceptance by all affected stakeholders. Participants in the meeting included representatives of state and regional regulatory agencies, utilities and power generators, the wind industry, environmental and landowner interests, and other interested parties (see Attachment A for a list of meeting participants).

  4. Plasmodium vivax Transmission in Africa.

    Directory of Open Access Journals (Sweden)

    Rosalind E Howes

    2015-11-01

    Full Text Available Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf. Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health

  5. Intercultural Transmission and Intergenerational Transmission in Immigrant Families.

    Science.gov (United States)

    Nauck, Bernhard

    2001-01-01

    Examined the impact of intergenerational transmission processes on the intercultural contact and ethnic identification of second generation adolescents from five migrant groups in Germany, distinguishing four possible outcomes of intercultural contact (integration, assimilation, segregation, and marginalization). Data from interviews with same-sex…

  6. Boundary stabilization of transmission problems

    Science.gov (United States)

    Cardoso, Fernando; Vodev, Georgi

    2010-02-01

    We study the transmission problem in bounded domains with dissipative boundary conditions. Under some natural assumptions, we prove uniform bounds of the corresponding resolvents on the real axis at high frequency and, as a consequence, we obtain regions free of eigenvalue. To this end, we extend the result of Cardoso et al. ["Distribution of resonances and local energy decay in the transmission problem. II," Math. Res. Lett. 6, 377 (1999)] under more general assumptions. As an application, we get exponential decay of the energy of the solutions of the corresponding mixed boundary value problems.

  7. Transmission pricing: paradigms and methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Shirmohammadi, Dariush [Pacific Gas and Electric Co., San Francisco, CA (United States); Vieira Filho, Xisto; Gorenstin, Boris [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Pereira, Mario V.P. [Power System Research, Rio de Janeiro, RJ (Brazil)

    1994-12-31

    In this paper we describe the principles of several paradigms and methodologies for pricing transmission services. The paper outlines some of the main characteristics of these paradigms and methodologies such as where they may be used for best results. Due to their popularity, power flow based MW-mile and short run marginal cost pricing methodologies will be covered in some detail. We conclude the paper with examples of the application of these two pricing methodologies for pricing transmission services in Brazil. (author) 25 refs., 2 tabs.

  8. Electromagnetic Transmission Through Resonant Structures

    Science.gov (United States)

    Young, Steven M.

    Electromagnetic resonators store energy in the form of oscillatory electric and magnetic fields and gradually exchange that energy by coupling with their environment. This coupling process can have profound effects on the transmission and reflection properties of nearby interfaces, with rapid transitions from high transmittance to high reflectance over narrow frequency ranges, and has been exploited to design useful optical components such as spectral filters and dielectric mirrors. This dissertation includes analytic, numeric, and experimental investigations of three different electromagnetic resonators, each based on a different method of confining electromagnetic fields near the region of interest. First, we show that a structure with two parallel conducting plates, each containing a subwavelength slit, supports a localized resonant mode bound to the slits and therefore exhibits (in the absence of nonradiative losses), perfect resonant transmission over a narrow frequency range. In practice, the transmission is limited by conduction losses in the sidewalls; nevertheless, experimental results at 10 GHz show a narrowband transmission enhancement by a factor of 104 compared to the non-resonant transmission, with quality factor (ratio of frequency to peak width) Q ~ 3000. Second, we describe a narrowband transmission filter based on a single-layer dielectric grating. We use a group theory analysis to show that, due to their symmetry, several of the grating modes cannot couple to light at normal incidence, while several others have extremely large coupling. We then show how selectively breaking the system symmetry using off-normal light incidence can produce transmission peaks by enabling weak coupling to some of the previously protected modes. The narrowband filtering capabilities are validated by an experimental demonstration in the long wavelength infrared, showing transmission peaks of quality factor Q ~ 100 within a free-spectral range of 8-15 mum. Third, we

  9. Transmission of Campylobacter coli in chicken embryos

    Directory of Open Access Journals (Sweden)

    Daise Aparecida Rossi

    2012-06-01

    Full Text Available Campylobacter coli is an important species involved in human cases of enteritis, and chickens are carriers of the pathogen mainly in developing country. The current study aimed to evaluate the transmission of C. coli and its pathogenic effects in chicken embryos. Breeder hens were inoculated intra-esophageally with C. coli isolated from chickens, and their eggs and embryos were analyzed for the presence of bacteria using real-time PCR and plate culture. The viability of embryos was verified. In parallel, SPF eggs were inoculated with C. coli in the air sac; after incubation, the embryos were submitted to the same analysis as the embryos from breeder hens. In embryos and fertile eggs from breeder hens, the bacterium was only identified by molecular methods; in the SPF eggs, however, the bacterium was detected by both techniques. The results showed no relationship between embryo mortality and positivity for C. coli in the embryos from breeder hens. However, the presence of bacteria is a cause of precocious mortality for SPF embryos. This study revealed that although the vertical transmission is a possible event, the bacteria can not grow in embryonic field samples.

  10. Periodic host absence can select for higher or lower parasite transmission rates

    OpenAIRE

    van den Berg, F.; Bacaer, N.; Metz, J. A. J.; Lannou, C.; van den Bosch, F.

    2011-01-01

    This paper explores the effect of discontinuous periodic host absence on the evolution of pathogen transmission rates by using R-0 maximisation techniques. The physiological consequence of an increased transmission rate can be either an increased virulence, i.e. there is a transmission-virulence trade-off or ii) a reduced between season survival, i.e. there is a transmission-survival trade-off. The results reveal that the type of trade-off determines the direction of selection, with relativel...

  11. Research Overview on Wireless Power Transmission Technology

    OpenAIRE

    Li Tao; Wu Liheng; Chen Zheng

    2015-01-01

    According to the latest researches, this paper outlines the development of wireless power transmission and introduces the latest applications of wireless power transmission in life. To describe the wireless power transmission technologies in detail, the paper presents the short-range, medium-range and remote wireless power transmission, respectively. In addition, the paper also depicts some unique properties of wireless power transmission system to make readers understand WPT system better. A...

  12. VIDEO TRANSMISSION SYSTEM IN ITV APPLICATION

    Institute of Scientific and Technical Information of China (English)

    WangYancai; WangQunwei; WangZhaohui

    1996-01-01

    The transmission characteristics of video transmission mediums,coaxial cable and optical fiber ,are discussed in the paper. The formulas for frequency bandwidthare given to evaluate the video transmission distance. For typical video transmissionsystems with BB/IM and PFM/IM using optical fiber as the channel, expressions andcalculating results for both SIN and sensitivity are given. Finally. the principle for selecting different type of transmission systems according to transmission distances of the industrial TV is presented.

  13. Tunable Transmission-Line Metamaterials Mimicking Electromagnetically Induced Transparency

    Science.gov (United States)

    Feng, T. H.; Han, H. P.

    2016-11-01

    Tunable transmission-line (TL) metamaterials mimicking electromagnetically induced transparency (EIT) have been studied. Firstly, two types of tunable TL EIT-like metamaterial, based on the double split-ring resonator (DSRR) and single split-ring resonator (SSRR), were fabricated and their transmission properties carefully compared. The results showed that the transmittance maximum was almost invariable with shift of the transparency window for the tunable DSRR-based TL EIT-like metamaterial, but for the tunable SSRR-based TL EIT-like metamaterial, the transmittance maximum gradually diminished with shift of the transparency window toward the center of the absorption band. Moreover, the reason for these different transmission properties was explored, revealing that the reduction of the transmittance maximum of the transparency window for the tunable SSRR-based TL EIT-like metamaterial is mainly due to energy loss caused by the resistance of the loaded varactor diodes.

  14. Suppression of glucocorticoid secretion enhances cholinergic transmission in rat hippocampus.

    Science.gov (United States)

    Mizoguchi, Kazushige; Shoji, Hirotaka; Ikeda, Ryuji; Tanaka, Yayoi; Maruyama, Wakako; Tabira, Takeshi

    2008-08-15

    We previously demonstrated that suppression of glucocorticoid secretion by adrenalectomy (ADX) impaired prefrontal cortex-sensitive working memory, but not reference memory. Since the cholinergic system in the hippocampus is also involved in these memories, we examined the effects of glucocorticoid suppression on cholinergic transmission in the rat hippocampus. A microdialysis study revealed that ADX did not affect the basal acetylcholine release, but enhanced the KCl-evoked response. This enhanced response was reversed by the corticosterone replacement treatment. The extracellular choline concentrations increased under both basal and KCl-stimulated conditions in the ADX rats, and these increases were also reversed by the corticosterone replacement. These results indicate that suppression of glucocorticoid secretion enhances cholinergic transmission in the hippocampus in response to stimuli. It is possible that this enhanced cholinergic transmission may not contribute to the ADX-induced working memory impairment, but it may be involved in maintenance of reference memory.

  15. Transmission Behavior of B Chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae).

    Science.gov (United States)

    Penitente, Manolo; Daniel, Sandro N; Senhorini, José A; Foresti, Fausto; Porto-Foresti, Fábio

    2015-01-01

    The population of Prochilodus lineatus found in the Mogi-Guaçu River is karyotypically polymorphic, carrying acrocentric, metacentric, and submetacentric B chromosomes. The analysis of each B chromosome frequency in this species revealed a variation in the distribution pattern, with the metacentric type having the highest frequency (73.30%), followed by submetacentric (25.22%) and acrocentric B chromosomes (1.48%). The transmission pattern of the supernumerary chromosomes was identified by controlled crosses, and it was shown that the acro- and submetacentric B chromosomes have a transmission pattern below the Mendelian rate (kB = 0.333 and kB = 0.385, respectively), but the metacentric variant has a cumulative transmission pattern (kB = 0.587). These results indicate that the acro- and submetacentric B chromosomes are undergoing an extinction process, while the metacentric B chromosomes appear to be accumulating in frequency with each generation.

  16. Climate drivers on malaria transmission in Arunachal Pradesh, India.

    Science.gov (United States)

    Upadhyayula, Suryanaryana Murty; Mutheneni, Srinivasa Rao; Chenna, Sumana; Parasaram, Vaideesh; Kadiri, Madhusudhan Rao

    2015-01-01

    The present study was conducted during the years 2006 to 2012 and provides information on prevalence of malaria and its regulation with effect to various climatic factors in East Siang district of Arunachal Pradesh, India. Correlation analysis, Principal Component Analysis and Hotelling's T² statistics models are adopted to understand the effect of weather variables on malaria transmission. The epidemiological study shows that the prevalence of malaria is mostly caused by the parasite Plasmodium vivax followed by Plasmodium falciparum. It is noted that, the intensity of malaria cases declined gradually from the year 2006 to 2012. The transmission of malaria observed was more during the rainy season, as compared to summer and winter seasons. Further, the data analysis study with Principal Component Analysis and Hotelling's T² statistic has revealed that the climatic variables such as temperature and rainfall are the most influencing factors for the high rate of malaria transmission in East Siang district of Arunachal Pradesh.

  17. Characteristics on Hydro-mechanical Transmission in Power Shift Process

    Institute of Scientific and Technical Information of China (English)

    HU Jibin; WEI Chao; YUAN Shihua; JING Chongbo

    2009-01-01

    To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed.The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can't be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.

  18. Light transmission of the ocular media in birds and mammals.

    Science.gov (United States)

    Tsukahara, Naoki; Tani, Yuri; Kikuchi, Hideyuki; Sugita, Shoei

    2014-01-01

    Differences in the ultraviolet (UV) cutoff of ocular media between birds and mammals have been revealed by spectrophotometric measurements of the transmission of light wavelengths by the cornea, lens and vitreous body in chickens, crows, quails, rats, rabbits and pigs. The light transmission values of the cornea were shown to be above 50% for wavelengths of 330-800 nm in birds, 300-800 nm in rat and 310-800 nm in mammals except for rat. For the lens, the light transmission values were shown to be above 50% for wavelengths of 320-800 nm in birds and rat and 390-800 nm in mammals except for rat. Thus, among the ocular media, the cornea in birds and the lens in mammals except for rat may play a role as a major UV cutoff filter.

  19. Wireless Power Transmission Using Microwaves

    Directory of Open Access Journals (Sweden)

    Nikhil B. Dhake

    2012-04-01

    Full Text Available In this paper, we present the concept of wireless power transmission to cut the clutter or lead to clean sources of electricity. It will eradicate the hazardous usage of electrical wires which involve lot of confusion in particularly organizing them. The plan is transmitting power as microwaves from one place to another in order to reduce the use of clumsy wires

  20. Neutron Transmission through Sapphire Crystals

    DEFF Research Database (Denmark)

    of simulations, in order to reproduce the transmission of cold neutrons through sapphire crystals. Those simulations were part of the effort of validating and improving the newly developed interface between the Monte-Carlo neutron transport code MCNP and the Monte Carlo ray-tracing code McStas....

  1. Transmission characteristics of BSE transponder

    Science.gov (United States)

    Yamamoto, M.; Fukuchi, H.; Kozu, T.; Igarashi, M.; Takeuchi, M.

    1986-01-01

    The transmission characteristics of the BSE transponder and their variation with the passage of time measured during the period from the beginning of BSE operation, May 1978 to March 1979, were previously reported. In this paper, the subsequent investigation completed by the time of the failure of the last high power amplifier of 100 watts of the BSE, June 1980, is discussed.

  2. Transmission analysis in WDM networks

    DEFF Research Database (Denmark)

    Rasmussen, Christian Jørgen

    1999-01-01

    This thesis describes the development of a computer-based simulator for transmission analysis in optical wavelength division multiplexing networks. A great part of the work concerns fundamental optical network simulator issues. Among these issues are identification of the versatility and user...... with a view of reducing the required number of bits....

  3. Microstructured Surfaces for Enhanced Transmission

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Bergmann, René; Kafka, Jan Robert;

    2014-01-01

    Binary microstructures are used to increase transmission of silicon (Si) surfaces in the infrared (IR) range. We consider hexagonal and square lattices with square and round pillars with the finitedifference frequency-domain (FDFD) method. In agreement with theory and previous publications, the h...

  4. Norovirus transmission on cruise ship.

    Science.gov (United States)

    Isakbaeva, Elmira T; Widdowson, Marc-Alain; Beard, R Suzanne; Bulens, Sandra N; Mullins, James; Monroe, Stephan S; Bresee, Joseph; Sassano, Patricia; Cramer, Elaine H; Glass, Roger I

    2005-01-01

    An outbreak of norovirus gastroenteritis affected passengers on two consecutive cruises of ship X and continued on 4 subsequent cruises despite a 1-week sanitization. We documented transmission by food and person-to-person contact; persistence of virus despite sanitization onboard, including introductions of new strains; and seeding of an outbreak on land.

  5. Heat reveals faults

    Energy Technology Data Exchange (ETDEWEB)

    Weinreich, Bernhard [Solarschmiede GmbH, Muenchen (Germany). Engineering Dept.

    2010-07-01

    Gremlins cannot hide from the all-revealing view of a thermographic camera, whereby it makes no difference whether it is a roof-mounted system or a megawatt-sized farm. Just as diverse are the range of faults that, with the growing level of expertise, can now be detected and differentiated with even greater detail. (orig.)

  6. Evidence of scrapie transmission via milk

    Directory of Open Access Journals (Sweden)

    Moore S Jo

    2008-04-01

    Full Text Available Abstract Background The risk of scrapie infection increases with increased duration and proximity of contact between sheep at lambing. Scrapie infectivity has not been detected in milk but cellular prion protein, the precursor of disease-associated prion protein PrPd, has been found in milk from ruminants. To determine whether milk is able to transmit scrapie, 18 lambs with a prion protein genotype associated with high susceptibility to scrapie (VRQ/VRQ were fed milk from twelve scrapie-affected ewes of the same genotype, and 15 VRQ/VRQ sheep reared on scrapie-free dams served as controls. Results Three lambs fed milk from scrapie-affected ewes were culled due to intercurrent diseases at 43, 44 and 105 days of age respectively, and PrPd was detected in the distal ileum of the first two lambs, whilst PrPd was not found in lymphoreticular tissues in the third lamb. A control lamb, housed in a separate pen and culled at 38 days of age, was also negative for PrPd in a range of tissues. Samples of recto-anal mucosa associated lymphoid tissue collected from the remaining 15 live lambs at seven months of age (between five to seven months after mixing were positive for PrPd in the scrapie milk recipients, whereas PrPd was not detected in the remaining 14 controls at that time. A subsequent sample collected from control lambs revealed PrPd accumulation in two of five lambs eight months after mixing with scrapie milk recipients suggestive of an early stage of infection via lateral transmission. By contrast, the control sheep housed in the same building but not mixed with the scrapie milk recipients were still negative for PrPd. Conclusion The presence of PrPd in distal ileum and rectal mucosa indicates transmission of scrapie from ewe to lamb via milk (or colostrum although it is not yet clear if such cases would go on to develop clinical disease. The high level of infection in scrapie-milk recipients revealed by rectal mucosal testing at approximately

  7. Transplacental transmission of Human Papillomavirus

    Directory of Open Access Journals (Sweden)

    Serafini Eduardo P

    2008-09-01

    Full Text Available Abstract This paper aimed at studying the transplacental transmission of HPV and looking at the epidemiological factors involved in maternal viral infection. The following sampling methods were used: (1 in the pregnant woman, (a genital; (b peripheral blood; (2 in the newborn, (a oral cavity, axillary and inguinal regions; (b nasopharyngeal aspirate, and (c cord blood; (3 in the placenta. The HPV DNA was identified using two methods: multiplex PCR of human β-globin and of HPV using the PGMY09 and PGMY11 primers; and nested-PCR, which combines degenerated primers of the E6/E7 regions of the HPV virus, that allowed the identification of genotypes 6/11, 16, 18, 31, 33, 42, 52 and 58. Transplacental transmission was considered when type-specific HPV concordance was found between the mother, the placenta and the newborn or the mother and cord blood. The study included 49 HPV DNA-positive pregnant women at delivery. Twelve placentas (24.5%, n = 12/49 had a positive result for HPV DNA. Eleven newborn were HPV DNA positive in samples from the nasopharyngeal or buccal and body or cord blood. In 5 cases (10.2%, n = 5/49 there was HPV type-specific agreement between genital/placenta/newborn samples. In one case (2%, n = 1/49 there was type specific HPV concordance between genital/cord blood and also suggested transplacental transmission. A positive and significant correlation was observed between transplacental transmission of HPV infection and the maternal variables of immunodepression history (HIV, p = 0.011. In conclusion the study suggests placental infection in 23.3% of the cases studied and transplacental transmission in 12.2%. It is suggested that in future HPV DNA be researched in the normal endometrium of women of reproductive age. The possible consequence of fetal exposure to HPV should be observed.

  8. Damage Detection and Quantification Using Transmissibility Coherence Analysis

    Directory of Open Access Journals (Sweden)

    Yun-Lai Zhou

    2015-01-01

    Full Text Available A new transmissibility-based damage detection and quantification approach is proposed. Based on the operational modal analysis, the transmissibility is extracted from system responses and transmissibility coherence is defined and analyzed. Afterwards, a sensitive-damage indicator is defined in order to detect and identify the severity of damage and compared with an indicator developed by other authors. The proposed approach is validated on data from a physics-based numerical model as well as experimental data from a three-story aluminum frame structure. For both numerical simulation and experiment the results of the new indicator reveal a better performance than coherence measure proposed in Rizos et al., 2008, Rizos et al., 2002, Fassois and Sakellariou, 2007, especially when nonlinearity occurs, which might be further used in real engineering. The main contribution of this study is the construction of the relation between transmissibility coherence and frequency response function coherence and the construction of an effective indicator based on the transmissibility modal assurance criteria for damage (especially for minor nonlinearity detection as well as quantification.

  9. Neurexin regulates nighttime sleep by modulating synaptic transmission

    Science.gov (United States)

    Tong, Huawei; Li, Qian; Zhang, Zi Chao; Li, Yi; Han, Junhai

    2016-01-01

    Neurexins are cell adhesion molecules involved in synaptic formation and synaptic transmission. Mutations in neurexin genes are linked to autism spectrum disorders (ASDs), which are frequently associated with sleep problems. However, the role of neurexin-mediated synaptic transmission in sleep regulation is unclear. Here, we show that lack of the Drosophila α-neurexin homolog significantly reduces the quantity and quality of nighttime sleep and impairs sleep homeostasis. We report that neurexin expression in Drosophila mushroom body (MB) αβ neurons is essential for nighttime sleep. We demonstrate that reduced nighttime sleep in neurexin mutants is due to impaired αβ neuronal output, and show that neurexin functionally couples calcium channels (Cac) to regulate synaptic transmission. Finally, we determine that αβ surface (αβs) neurons release both acetylcholine and short neuropeptide F (sNPF), whereas αβ core (αβc) neurons release sNPF to promote nighttime sleep. Our findings reveal that neurexin regulates nighttime sleep by mediating the synaptic transmission of αβ neurons. This study elucidates the role of synaptic transmission in sleep regulation, and might offer insights into the mechanism of sleep disturbances in patients with autism disorders. PMID:27905548

  10. 76 FR 49841 - Transmission Planning and Cost Allocation by Transmission Owning and Operating Public Utilities

    Science.gov (United States)

    2011-08-11

    ... process, procedures for joint evaluation and sharing of information regarding the respective transmission... data and information between neighboring transmission planning regions at least annually. 9. Finally... of power flows over an interconnected transmission system. In particular, the...

  11. Stream Control Transmission Protocol Steganography

    CERN Document Server

    Fraczek, Wojciech; Szczypiorski, Krzysztof

    2010-01-01

    Stream Control Transmission Protocol (SCTP) is a new transport layer protocol that is due to replace TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) protocols in future IP networks. Currently, it is implemented in such operating systems like BSD, Linux, HP-UX or Sun Solaris. It is also supported in Cisco network devices operating system (Cisco IOS) and may be used in Windows. This paper describes potential steganographic methods that may be applied to SCTP and may pose a threat to network security. Proposed methods utilize new, characteristic SCTP features like multi-homing and multistreaming. Identified new threats and suggested countermeasures may be used as a supplement to RFC 5062, which describes security attacks in SCTP protocol and can induce further standard modifications.

  12. Exploiting a Transmission Grating Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ronald E. Bell

    2004-12-08

    The availability of compact transmission grating spectrometers now allows an attractive and economical alternative to the more familiar Czerny-Turner configuration for many high-temperature plasma applications. Higher throughput is obtained with short focal length refractive optics and stigmatic imaging. Many more spectra can be obtained with a single spectrometer since smaller, more densely packed optical input fibers can be used. Multiple input slits, along with a bandpass filter, can be used to maximize the number of spectra per detector, providing further economy. Curved slits can correct for the strong image curvature of the short focal length optics. Presented here are the governing grating equations for both standard and high-dispersion transmission gratings, defining dispersion, image curvature, and desired slit curvature, that can be used in the design of improved plasma diagnostics.

  13. Transmission capacity of wireless networks

    CERN Document Server

    Weber, Steven

    2012-01-01

    Transmission capacity (TC) is a performance metric for wireless networks that measures the spatial intensity of successful transmissions per unit area, subject to a constraint on the permissible outage probability (where outage occurs when the SINR at a receiver is below a threshold). This volume gives a unified treatment of the TC framework that has been developed by the authors and their collaborators over the past decade. The mathematical framework underlying the analysis (reviewed in Ch. 2) is stochastic geometry: Poisson point processes model the locations of interferers, and (stable) shot noise processes represent the aggregate interference seen at a receiver. Ch. 3 presents TC results (exact, asymptotic, and bounds) on a simple model in order to illustrate a key strength of the framework: analytical tractability yields explicit performance dependence upon key model parameters. Ch. 4 presents enhancements to this basic model --- channel fading, variable link distances, and multi-hop. Ch. 5 presents four...

  14. Transmission of influenza A viruses.

    Science.gov (United States)

    Neumann, Gabriele; Kawaoka, Yoshihiro

    2015-05-01

    Influenza A viruses cause respiratory infections that range from asymptomatic to deadly in humans. Widespread outbreaks (pandemics) are attributable to 'novel' viruses that possess a viral hemagglutinin (HA) gene to which humans lack immunity. After a pandemic, these novel viruses form stable virus lineages in humans and circulate until they are replaced by other novel viruses. The factors and mechanisms that facilitate virus transmission among hosts and the establishment of novel lineages are not completely understood, but the HA and basic polymerase 2 (PB2) proteins are thought to play essential roles in these processes by enabling avian influenza viruses to infect mammals and replicate efficiently in their new host. Here, we summarize our current knowledge of the contributions of HA, PB2, and other viral components to virus transmission and the formation of new virus lineages.

  15. Terahertz metamaterial with asymmetric transmission

    CERN Document Server

    Singh, R; Menzel, C; Rockstuhl, C; Azad, A K; Cheville, R A; Lederer, F; Zhang, W; Zheludev, N I

    2009-01-01

    We show for the first time that a planar metamaterial, an array of coupled metal split-ring resonators with a unit cell lacking mirror symmetry, exhibits asymmetric transmission of terahertz radiation propagating through it in opposite directions. This intriguing effect, that is compatible with Lorentz reciprocity and time-reversal, depends on a directional difference in conversion efficiency of the incident circularly polarized wave into one of opposite handedness, that is only possible in lossy low-symmetry planar chiral metamaterials. We show that asymmetric transmission is linked to excitation of enantiomerically sensitive plasmons, these are induced charge-field excitations that depend on the mutual handedness of incident wave and metamaterial pattern. Various bands of positive, negative and zero phase and group velocities have been identified indicating the opportunity to develop polarization sensitive negative index and slow light media based on such metamaterials.

  16. Monitoring Atmospheric Transmission with FLAME

    Science.gov (United States)

    Zimmer, Peter C.; McGraw, J. T.; Zirzow, D. C.; Koppa, M.; Buttler-Pena, K.

    2014-01-01

    Calibration of ground-based observations in the optical and near-infrared requires precise and accurate understanding of atmospheric transmission, at least as precise and accurate as that required for the spectral energy distributions of science targets. Traditionally this has used the Langley extrapolation method, observing targets and calibrators over a range of airmass and extrapolating to zero airmass by assuming a plane-parallel homogeneous atmosphere. The technique we present uses direct measurements of the atmosphere to derive the transmission along the line of sight to science targets at a few well-chosen wavelengths. The Facility Lidar Atmospheric Monitor of Extinction (FLAME) is a 0.5m diameter three Nd:YAG wavelength (355nm, 532nm & 1064nm) elastic backscatter lidar system. Laser pulses are transmitted into the atmosphere in the direction of the science target. Photons scattered back toward the receiver by molecules, aerosols and clouds are collected and time-gated so that the backscatter intensity is measured as a function of range to the scattering volume. The system is housed in a mobile calibration lab, which also contains auxiliary instrumentation to provide a NIST traceable calibration of the transmitted laser power and receiver efficiency. FLAME was designed to create a million photons per minute signal from the middle stratosphere, where the atmosphere is relatively calm and dominated by molecules of the well-mixed atmosphere (O2 & N2). Routine radiosonde measurements of the density at these altitudes constrain the scattering efficiency in this region and, combined with calibration of the transmitter and receiver, the only remaining unknown quantity is the two-way transmission to the stratosphere. These measurements can inform atmospheric transmission models to better understand the complex and ever-changing observatory radiative transfer environment. FLAME is currently under active development and we present some of our ongoing measurements.

  17. Analysis of Wireless Power Transmission

    OpenAIRE

    2013-01-01

    The advent of various wireless technologies have revolutionized the communication infrastructure and consequently changed the entire world into a global village. Use of wireless technology has also been made for transmission of electric power wirelessly. It increases the portability of power systems and integrates the communication technologies and electric power to the same platform. This paper presents a comprehensive review and detailed analysis of various techniques used for wireless powe...

  18. Advanced Rotorcraft Transmission program summary

    Science.gov (United States)

    Bossler, Robert B., Jr.; Heath, Gregory F.

    1992-07-01

    The current status of the Advanced Rotorcraft Transmission (ART) program is reviewed. The discussion includes a general configuration and face gear description, weight analysis, stress analysis, reliability analysis, acoustic analysis, face gear testing, and planned torque split testing. Design descriptions include the face gear webs sized for equal stiffness, a positive engagement clutch, the lubrication system, and a high contact ratio planetary. Test results for five gear materials and three housing materials are presented.

  19. Transmission risk of human trichinellosis.

    Science.gov (United States)

    Takumi, Katsuhisa; Teunis, Peter; Fonville, Manoj; Vallee, Isabelle; Boireau, Pascal; Nöckler, Karsten; van der Giessen, Joke

    2009-02-23

    Trichinella is a food-borne parasitic zoonoses and human cases are still reported in Europe mainly due to the consumption of pig meat originating from small backyard farms. Infections originating from industrialized pig farming have not been reported for decades in Europe, due to control measures to prevent the transmission of Trichinella from wildlife by indoor housing and good management practices. Therefore, risk-based monitoring programs might replace individual carcass control in industrialized pig farming as described in EU legislation SANCO 2075/2005. Transmission of Trichinella species between wildlife and the risk that may pose to humans via consumption of contaminated pork meat has not been studied quantitatively. One pathway by which human trichinellosis can occur is the rat-pig-human route. To evaluate the transmission risk though this pathway the dose responses of rat, pig, and human were studied. Experimental T. spiralis infection was performed in rats with doses of as few as 10 parasites and the data set was analysed using a newly developed dose response model that describes larvae per gram (LPG). Experimental T. spiralis infection in pig was analysed in a similar way. Furthermore nine published outbreaks of human trichinellosis were analysed to determine the dose response in humans. The risk of human trichinellosis via the rat-pig-human transmission was simulated by the Monte Carlo method. A pair of female and male parasites representing the lowest infection pressure from the environment, led to the probability of human trichinellosis by consumption of 100g of raw pork meat equal to 5% via the studied rat-pig-human pathway. In the absence of rodent control near the farm, a low infection pressure from wildlife presents a relatively high risk of human trichinellosis via consumption of uncooked pork meat.

  20. ac transmission line field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kotter, F.R.; Misakian, M.

    1977-11-01

    The concern in recent years over the environmental effects of electric and magnetic fields from high voltage transmission lines has also focused attention on the accuracy of measurements of these fields. Electric field meters are discussed in terms of theory of operation, parameters affecting performance, meter performance under field and laboratory conditions, and calibration procedures. The performance and calibration of magnetic field meters is described. (LCL)

  1. Transmission and distribution electrical engineering

    CERN Document Server

    Bayliss, Colin

    2003-01-01

    This comprehensive treatment of the theory and practice encountered in the installation and design of transmission and distribution systems for electrical power has been updated and revised to provide the project engineer with all the latest, relevant information to design and specify the correct system for a particular application.Thoroughly updated and revised to include latest developmentsLearn from and Author with extensive experience in managing international projectsFind out the reasoning and implicatons behind the different specifications and methods

  2. Coiled transmission line pulse generators

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Kenneth Fox (Columbia, MO)

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  3. Disruption of Plasmodium Sporozoite Transmission by Depletion of Sporozoite Invasion-Associated Protein 1▿ §

    OpenAIRE

    2009-01-01

    Accumulation of infectious Plasmodium sporozoites in Anopheles spp. salivary glands marks the final step of the complex development of the malaria parasite in the insect vector. Sporozoites are formed inside midgut-associated oocysts and actively egress into the mosquito hemocoel. Traversal of the salivary gland acinar cells correlates with the sporozoite's capacity to perform continuous gliding motility. Here, we characterized the cellular role of the Plasmodium berghei sporozoite invasion-a...

  4. TypeScript revealed

    CERN Document Server

    Maharry, Dan

    2013-01-01

    TypeScript Revealed is a quick 100-page guide to Anders Hejlsberg's new take on JavaScript. With this brief, fast-paced introduction to TypeScript, .NET, Web and Windows 8 application developers who are already familiar with JavaScript will easily get up to speed with TypeScript and decide whether or not to start incorporating it into their own development. TypeScript is 'JavaScript for Application-scale development'; a superset of JavaScript that brings to it an additional object-oriented-like syntax familiar to .NET programmers that compiles down into simple, clean JavaScript that any browse

  5. Mycobacterial factors relevant for transmission of tuberculosis

    NARCIS (Netherlands)

    Verhagen, L.M.; Hof, S. van den; Deutekom, H. van; Hermans, P.W.M.; Kremer, K.; Borgdorff, M.W.; Soolingen, D. van

    2011-01-01

    BACKGROUND: Tuberculosis (TB) transmission is associated with patient-related risk factors. However, DNA fingerprint analysis has provided anecdotal evidence suggesting a role for bacteriological factors. METHODS: To examine the importance of the bacteriological component in TB transmission, we inve

  6. Sevick's transmission line transformers theory and practice

    CERN Document Server

    Mack, Raymond

    2014-01-01

    An updated and reorganized revision of the classic book Transmission Line Transformers (2001) by Jerry Sevick, this book provides communication engineers with a clear technical presentation of both the theory and practical applications of the transmission of radio communication.

  7. Integrated Transmission and Distribution Control

    Energy Technology Data Exchange (ETDEWEB)

    Kalsi, Karanjit; Fuller, Jason C.; Tuffner, Francis K.; Lian, Jianming; Zhang, Wei; Marinovici, Laurentiu D.; Fisher, Andrew R.; Chassin, Forrest S.; Hauer, Matthew L.

    2013-01-16

    Distributed, generation, demand response, distributed storage, smart appliances, electric vehicles and renewable energy resources are expected to play a key part in the transformation of the American power system. Control, coordination and compensation of these smart grid assets are inherently interlinked. Advanced control strategies to warrant large-scale penetration of distributed smart grid assets do not currently exist. While many of the smart grid technologies proposed involve assets being deployed at the distribution level, most of the significant benefits accrue at the transmission level. The development of advanced smart grid simulation tools, such as GridLAB-D, has led to a dramatic improvement in the models of smart grid assets available for design and evaluation of smart grid technology. However, one of the main challenges to quantifying the benefits of smart grid assets at the transmission level is the lack of tools and framework for integrating transmission and distribution technologies into a single simulation environment. Furthermore, given the size and complexity of the distribution system, it is crucial to be able to represent the behavior of distributed smart grid assets using reduced-order controllable models and to analyze their impacts on the bulk power system in terms of stability and reliability. The objectives of the project were to: • Develop a simulation environment for integrating transmission and distribution control, • Construct reduced-order controllable models for smart grid assets at the distribution level, • Design and validate closed-loop control strategies for distributed smart grid assets, and • Demonstrate impact of integrating thousands of smart grid assets under closed-loop control demand response strategies on the transmission system. More specifically, GridLAB-D, a distribution system tool, and PowerWorld, a transmission planning tool, are integrated into a single simulation environment. The integrated environment

  8. Revealing the programming process

    DEFF Research Database (Denmark)

    Bennedsen, Jens; Caspersen, Michael Edelgaard

    2005-01-01

    One of the most important goals of an introductory programming course is that the students learn a systematic approach to the development of computer programs. Revealing the programming process is an important part of this; however, textbooks do not address the issue -- probably because the textb......One of the most important goals of an introductory programming course is that the students learn a systematic approach to the development of computer programs. Revealing the programming process is an important part of this; however, textbooks do not address the issue -- probably because...... the textbook medium is static and therefore ill-suited to expose the process of programming. We have found that process recordings in the form of captured narrated programming sessions are a simple, cheap, and efficient way of providing the revelation.We identify seven different elements of the programming...... process for which process recordings are a valuable communication media in order to enhance the learning process. Student feedback indicates both high learning outcome and superior learning potential compared to traditional classroom teaching....

  9. INFINITELY VARIABLE TRANSMISSION USING FOUR BAR MECHANISM

    OpenAIRE

    Dr.N. ARUNKUMAR; Santhosh, R.; S. SUNIL SUBRAMANIAM

    2014-01-01

    Most of the continuously variable transmission systems in automobiles now-a-days are non-positive drives. This means that they cannot be used in heavy vehicles that require very high torque to be transmitted. This new type of infinitely variable transmission is aimed at transmitting high torques by making it a positive drive, thus making continuously variable transmission systems to be suitable for heavy vehicles. Infinitely variable transmission system and continuously variable transmissi...

  10. Advanced Power Transmission of the Future

    OpenAIRE

    Rabinowitz, Mario

    2003-01-01

    Electric power is a vital ingredient of modern society. This article is written to provide an insight into the physics and engineering that go into the transmission of electric power and its potential modernization. Topics covered will be Transmission and Distribution, Comparing Overhead and Underground Delivery, Pros and Cons of Underground Delivery, Superconducting Transmission, Cryorisistive Delivery, Hyperconductivity, and Metal-Plated Graphite Fibers.

  11. Fractional Frequency Transmission System and Its Applications

    Institute of Scientific and Technical Information of China (English)

    WANG Xifan; WANG Xiuli; TENG Yufei

    2012-01-01

    In 1994, we proposed transmission approach, the a novel fractional electricity frequency transmission system (FFTS), which uses lower frequency (50/3 Hz) to reduce the electrical length of AC power lines and thus obviously increases transmission capacity. The system is especially suitable to transmit remote renewable power such as hydro power and wind power.

  12. Malaria transmission rates estimated from serological data.

    OpenAIRE

    Burattini, M. N.; Massad, E; Coutinho, F. A.

    1993-01-01

    A mathematical model was used to estimate malaria transmission rates based on serological data. The model is minimally stochastic and assumes an age-dependent force of infection for malaria. The transmission rates estimated were applied to a simple compartmental model in order to mimic the malaria transmission. The model has shown a good retrieving capacity for serological and parasite prevalence data.

  13. 40 CFR 86.528-78 - Transmissions.

    Science.gov (United States)

    2010-07-01

    ... be conducted with automatic transmissions in “Drive” (highest gear). Automatic clutch-torque... shall be in gear with the clutch disengaged; except first idle, see §§ 86.536 and 86.537. (d) The... transmissions shall shift automatically through the normal sequence of gears; manual transmissions shall...

  14. Average Transmission Probability of a Random Stack

    Science.gov (United States)

    Lu, Yin; Miniatura, Christian; Englert, Berthold-Georg

    2010-01-01

    The transmission through a stack of identical slabs that are separated by gaps with random widths is usually treated by calculating the average of the logarithm of the transmission probability. We show how to calculate the average of the transmission probability itself with the aid of a recurrence relation and derive analytical upper and lower…

  15. Topics on Electricity Transmission Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerndal, Mette

    2000-02-01

    Within the last decade we have experienced deregulation of several industries, such as airlines, telecommunications and the electric utility industry, the last-mentioned being the focus of this work. Both the telecommunications and the electricity sector depend on network facilities, some of which are still considered as natural monopolies. In these industries, open network access is regarded as crucial in order to achieve the gains from increased competition, and transmission tariffs are important in implementing this. Based on the Energy Act that was introduced in 1991, Norway was among the first countries to restructure its electricity sector. On the supply side there are a large number of competing firms, almost exclusively hydro plants, with a combined capacity of about 23000 MW, producing 105-125 TWh per year, depending on the availability of water. Hydro plants are characterized by low variable costs of operation, however since water may be stored in dams, water has an opportunity cost, generally known as the water value, which is the shadow price of water when solving the generator's inter temporal profit maximization problem. Water values are the main factor of the producers' short run marginal cost. Total consumption amounts to 112-117 TWh a year, and consumers, even households, may choose their electricity supplier independent of the local distributor to which the customer is connected. In fact, approximately 10% of the households have actually changed supplier. The web-site www.konkurransetilsynet.no indicates available contracts, and www.dinside.no provides an ''energy-calculator'' where one can check whether it is profitable to switch supplier. If a customer buys energy from a remote supplier, the local distributor only provides transportation facilities for the energy and is compensated accordingly. Transmission and distribution have remained monopolized and regulated by the Norwegian Water Resources and Energy

  16. Topics in Electricity Transmission Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerndal, Mette

    2000-02-01

    Within the last decade we have experienced deregulation of several industries, such as airlines, telecommunications and the electric utility industry, the last-mentioned being the focus of this work. Both the telecommunications and the electricity sector depend on network facilities, some of which are still considered as natural monopolies. In these industries, open network access is regarded as crucial in order to achieve the gains from increased competition, and transmission tariffs are important in implementing this. Based on the Energy Act that was introduced in 1991, Norway was among the first countries to restructure its electricity sector. On the supply side there are a large number of competing firms, almost exclusively hydro plants, with a combined capacity of about 23000 MW, producing 105-125 TWh per year, depending on the availability of water. Hydro plants are characterized by low variable costs of operation, however since water may be stored in dams, water has an opportunity cost, generally known as the water value, which is the shadow price of water when solving the generator's inter temporal profit maximization problem. Water values are the main factor of the producers' short run marginal cost. Total consumption amounts to 112-117 TWh a year, and consumers, even households, may choose their electricity supplier independent of the local distributor to which the customer is connected. In fact, approximately 10% of the households have actually changed supplier. The web-site www.konkurransetilsynet.no indicates available contracts, and www.dinside.no provides an ''energy-calculator'' where one can check whether it is profitable to switch supplier. If a customer buys energy from a remote supplier, the local distributor only provides transportation facilities for the energy and is compensated accordingly. Transmission and distribution have remained monopolized and regulated by the Norwegian Water Resources and Energy

  17. Virological factors that increase the transmissibility of emerging human viruses.

    Science.gov (United States)

    Geoghegan, Jemma L; Senior, Alistair M; Di Giallonardo, Francesca; Holmes, Edward C

    2016-04-12

    The early detection of pathogens with epidemic potential is of major importance to public health. Most emerging infections result in dead-end "spillover" events in which a pathogen is transmitted from an animal reservoir to a human but is unable to achieve the sustained human-to-human transmission necessary for a full-blown epidemic. It is therefore critical to determine why only some virus infections are efficiently transmitted among humans whereas others are not. We sought to determine which biological features best characterized those viruses that have achieved sustained human transmission. Accordingly, we compiled a database of 203 RNA and DNA human viruses and used an information theoretic approach to assess which of a set of key biological variables were the best predictors of human-to-human transmission. The variables analyzed were as follows: taxonomic classification; genome length, type, and segmentation; the presence or absence of an outer envelope; recombination frequency; duration of infection; host mortality; and whether or not a virus exhibits vector-borne transmission. This comparative analysis revealed multiple strong associations. In particular, we determined that viruses with low host mortality, that establish long-term chronic infections, and that are nonsegmented, nonenveloped, and, most importantly, not transmitted by vectors were more likely to be transmissible among humans. In contrast, variables including genome length, genome type, and recombination frequency had little predictive power. In sum, we have identified multiple biological features that seemingly determine the likelihood of interhuman viral transmissibility, in turn enabling general predictions of whether viruses of a particular type will successfully emerge in human populations.

  18. Android Emotions Revealed

    DEFF Research Database (Denmark)

    Vlachos, Evgenios; Schärfe, Henrik

    2012-01-01

    This work presents a method for designing facial interfaces for sociable android robots with respect to the fundamental rules of human affect expression. Extending the work of Paul Ekman towards a robotic direction, we follow the judgment-based approach for evaluating facial expressions to test...... in which case an android robot like the Geminoid|DK –a duplicate of an Original person- reveals emotions convincingly; when following an empirical perspective, or when following a theoretical one. The methodology includes the processes of acquiring the empirical data, and gathering feedback on them. Our...... findings are based on the results derived from a number of judgments, and suggest that before programming the facial expressions of a Geminoid, the Original should pass through the proposed procedure. According to our recommendations, the facial expressions of an android should be tested by judges, even...

  19. EM transmission-line metamaterials

    Directory of Open Access Journals (Sweden)

    George V. Eleftheriades

    2009-03-01

    Full Text Available Metamaterials are understood to be artificially engineered materials that exhibit unusual or difficult to obtain electromagnetic (EM properties. Such properties would include negative or low values of permittivity, permeability and index of refraction. In this article, we review the fundamentals of metamaterials with emphasis on negative-refractive-index ones, which are synthesized using loaded transmission lines. A number of applications of such metamaterials are discussed, including peculiar lenses that can overcome the diffraction limit and small antennas for emerging wireless communication applications.

  20. Corrosive effects of hvdc transmission

    Energy Technology Data Exchange (ETDEWEB)

    Cornwell, F.E.; Backstrom, T.E.

    1966-02-01

    Field tests using ac transmission lines for introduction of direct current into the earth at widely separated points are described. One test circuit was between a Tracy pumping plant and a Shasta power plant in California, and two others were in the Hoover power plant area. Evaluation of the effects of such ground currents on corrosion of buried metalwork was a primary aim of the tests. Potential gradients, pipe-to-soil potentials, and soil resistivities are discussed in detail. Estimates are made of the distances from ehv dc terminal installations within which corrosion prevention procedures may become necessary.

  1. Transmission system planning in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Barrie, D.; Macedo, F.X.; Mcconnach, J.S. [Ontario Hydro, Toronto, ON (Canada)

    1994-12-31

    In recent years, new and modified approaches to planning the large transmission system that serves the province of Ontario, Canada, have been necessary to accommodate the rapidly changing planning environment including slower uncertain growth, ageing of facilities, integration of demand side management and non utility generation options, increased competitiveness, increased financial stresses and affordable constraints. This paper describes some of the new and modified approaches and tools that have been adopted or are being developed by Ontario Hydro to cope with this changing environment. (author) 9 refs., 4 figs.

  2. Force transmission in epithelial tissues.

    Science.gov (United States)

    Vasquez, Claudia G; Martin, Adam C

    2016-03-01

    In epithelial tissues, cells constantly generate and transmit forces between each other. Forces generated by the actomyosin cytoskeleton regulate tissue shape and structure and also provide signals that influence cells' decisions to divide, die, or differentiate. Forces are transmitted across epithelia because cells are mechanically linked through junctional complexes, and forces can propagate through the cell cytoplasm. Here, we review some of the molecular mechanisms responsible for force generation, with a specific focus on the actomyosin cortex and adherens junctions. We then discuss evidence for how these mechanisms promote cell shape changes and force transmission in tissues.

  3. 49 CFR 191.13 - Distribution systems reporting transmission pipelines; transmission or gathering systems...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution systems reporting transmission pipelines; transmission or gathering systems reporting distribution pipelines. 191.13 Section 191.13... Distribution systems reporting transmission pipelines; transmission or gathering systems reporting...

  4. 49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

    Science.gov (United States)

    2010-10-01

    ... position. S3.1.2Transmission braking effect. In vehicles having more than one forward transmission gear... when the transmission shift position is in any forward drive gear; (b) The engine may not automatically stop when the transmission is in reverse gear; and (c) The engine may automatically restart in...

  5. Magnetic Force Transmission of a Reciprocating Motion

    Institute of Scientific and Technical Information of China (English)

    Qing-chang Tan; Fu-sheng Zheng; Jian-gang Li

    2008-01-01

    Magnetic force transmission of a reciprocating motion is studied by theoretical analysis and experiment. A mathematical model for calculating the magnetic force is derived using the theory of equivalent magnetic charges. An experimental rig is constructed to test the transmission and the model is verified by experiment. Effect of the transmission parameters on the magnetic force is analyzed theoretically from the model, and characteristic of the transmission is studied experimentally. Since the transmission is without direct contact between two elements, it is suitable for application in an organism.

  6. ENERGY EFFICIENCY OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSION TESTS AT LOCOMOTIVE REPAIR PLANT

    Directory of Open Access Journals (Sweden)

    B. E. Bodnar

    2015-10-01

    Full Text Available Purpose. In difficult economic conditions, cost reduction of electricity consumption for the needs of production is an urgent task for the country’s industrial enterprises. Technical specifications of enterprises, which repair diesel locomotive hydraulic transmission, recommend conducting a certain amount of evaluation and regulatory tests to monitor their condition after repair. Experience shows that a significant portion of hydraulic transmission defects is revealed by bench tests. The advantages of bench tests include the ability to detect defects after repair, ease of maintenance of the hydraulic transmission and relatively low labour intensity for eliminating defects. The quality of these tests results in the transmission resource and its efficiency. Improvement of the technology of plant post-repairs hydraulic tests in order to reduce electricity consumption while testing. Methodology. The possible options for hydraulic transmission test bench improvement were analysed. There was proposed an energy efficiency method for diesel locomotive hydraulic transmission testing in locomotive repair plant environment. This is achieved by installing additional drive motor which receives power from the load generator. Findings. Based on the conducted analysis the necessity of improving the plant stand testing of hydraulic transmission was proved. The variants of the stand modernization were examined. The test stand modernization analysis was conducted. Originality. The possibility of using electric power load generator to power the stand electric drive motor or the additional drive motor was theoretically substantiated. Practical value. A variant of hydraulic transmission test stand based on the mutual load method was proposed. Using this method increases the hydraulic transmission load range and power consumption by stand remains unchanged. The additional drive motor will increase the speed of the input shaft that in its turn wil allow testing in

  7. Open Access Transmission and Renewable Energy Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Porter, K.

    1996-09-01

    In April 1996, the Federal Regulatory Commission (PERC) approved Orders 888 and 889 and released a draft rule for public comment on capacity reservation tariffs (CRTs). Order No. 888 requires electric utilities to file transmission tariffs that would allow transmission access to third parties who want to conduct wholesale transactions, and Order No. 889 requires transmission-owning utilities to set up open access, same-time information systems (OASIS), using commercial software and Internet protocols. This paper discusses these Orders in detail, as well as some of the issues before FERC with implications for renewables, which include: transmission pricing; transmission terms and conditions; reassignment of transmission capacity; defining state and FERC jurisdiction over transmission and distribution; the pricing of ancillary services; and the adoption and implementation of independent system operators.

  8. Energy transmission using recyclable quantum entanglement

    Science.gov (United States)

    Ye, Ming-Yong; Lin, Xiu-Min

    2016-07-01

    It is known that faster-than-light (FTL) transmission of energy could be achieved if the transmission were considered in the framework of non-relativistic classical mechanics. Here we show that FTL transmission of energy could also be achieved if the transmission were considered in the framework of non-relativistic quantum mechanics. In our transmission protocol a two-spin Heisenberg model is considered and the energy is transmitted by two successive local unitary operations on the initially entangled spins. Our protocol does not mean that FTL transmission can be achieved in reality when the theory of relativity is considered, but it shows that quantum entanglement can be used in a recyclable way in energy transmission.

  9. Chitosan conjugated chloroquine: proficient to protect the induction of liver apoptosis during malaria.

    Science.gov (United States)

    Tripathy, Satyajit; Chattopadhyay, Sourav; Dash, Sandeep Kumar; Chowdhuri, Angshuman Ray; Das, Sabyasachi; Sahu, Sumanta Kumar; Majumdar, Subrata; Roy, Somenath

    2015-03-01

    Chitosan has impelled continuous motion by its unique physicochemical and biological characteristics. In our study, chitosan-tripolyphosphate (CS-TPP) particles was conjugated with an undervalued antimalarial drug, chloroquine to find out the proficiency against ROS mediated caspase activation and apoptosis in liver during Plasmodium berghei NK65 infection. The transmission electron microscopic image illustrated the size range of particle was less than 50 nm and the particle showed the blood compatibility. ROS generation, mitochondrial membrane potential, anti apoptotic and pro apoptotic protein level of CS-TPP conjugated chloroquine treated group revealed that CS-TPP conjugation amplified the protective capability of chloroquine. FACS study by annexin v-FITC and PI staining reveals chloroquine treatment reduces significantly (Pagainst P. berghei induced liver apoptosis. This study suggests that proficiency of conventional antimalarial drug may escalate by delivery with chitosan nanoparticles to portray defense possessions against malarial damage.

  10. Exoplanet Transmission Spectroscopy using KMOS

    CERN Document Server

    Parviainen, Hannu; Thatte, Niranjan; Barstow, Joanna K; Evans, Thomas M; Gibson, Neale

    2015-01-01

    KMOS (K-Band Multi Object Spectrograph) is a novel integral field spectrograph installed in the VLT's ANTU unit. The instrument offers an ability to observe 24 2.8"$\\times$2.8" sub-fields positionable within a 7.2' patrol field, each sub-field producing a spectrum with a 14$\\times$14-pixel spatial resolution. The main science drivers for KMOS are the study of galaxies, star formation, and molecular clouds, but its ability to simultaneously measure spectra of multiple stars makes KMOS an interesting instrument for exoplanet atmosphere characterization via transmission spectroscopy. We set to test whether transmission spectroscopy is practical with KMOS, and what are the conditions required to achieve the photometric precision needed, based on observations of a partial transit of WASP-19b, and full transits of GJ 1214b and HD 209458b. Our analysis uses the simultaneously observed comparison stars to reduce the effects from instrumental and atmospheric sources, and Gaussian processes to model the residual system...

  11. Wildlife and electric power transmission

    Science.gov (United States)

    Ellis, D.H.; Goodwin, J.G.; Hunt, J.R.; Fletcher, John L.; Busnel, R.G.

    1978-01-01

    Hundreds of thousands of miles of transmission lines have been introduced into our natural environment. These lines and their corridors can be damaging or beneficial to wildlife communities depending on how they are designed, where they are placed, and when they are constructed and maintained. With the current trend toward UHV systems, new problems (associated with additional increments in audible noise, electric and magnetic force fields, etc.) must be addressed. We recommend the following areas for careful study: (1) the response of wilderness species to transmission lines and line construction and maintenance activities (2) the magnitude of bird collision and electrocution mortality, (3) the response of power corridor and power tower in habiting wildlife to laboratory and field doses of electro-chemical oxidants, corona noise, electric and magnetic fields, etc., (4) the productivity of tower inhabiting birds compared with nearby non-tower nesters, and (5) the influence of powerline corridors on mammalian and avian migration patterns. It is our hope that the questions identified in this study will help stimulate further research so that we can maximize wildlife benefits and minimize wildlife detriments.

  12. Propagation of disturbances as voltage fluctuations in transmission networks

    Directory of Open Access Journals (Sweden)

    Albert Hermina

    2016-08-01

    Full Text Available Significant changes occurred in the power system in Romania in recent years by reducing the power used in the system, the number of classic power sources in operation as well as by implementing renewable energy sources, have determined short circuit power reduction (node rigidity in the points where disturbing users are connected, that in the absence of adequate measures, result in disturbances above acceptable levels. The paper analyzes two power systems areas in which are connected users that cause voltage fluctuation. Disturbances as voltage fluctuations resulting in these nodes may exceed the acceptable values and can spread in the transmission network affecting power quality over large system areas. The analysis conducted reveals the influence of short circuit power in nodes where these users are connected and highlights the fact that in some cases (e.g. lines out of operation for maintenance, shutdown of classic units in the area the disturbances in the transmission network sent to the users at lower voltages may have values above those allowed. Technical Code of existing power transmission network makes no reference to voltage fluctuations, as a rule, in the electricity transmission network was considered that this phenomenon should not exist.

  13. Natural maternal transmission of H pylori in Mongolian gerbils

    Institute of Scientific and Technical Information of China (English)

    Jin-Uk Lee; Okjin Kim

    2006-01-01

    AIM: To investigate maternal H pylori infection status to determine the potential of maternal transmission.METHODS: In the present study, we examined these issues in an experimental murine model, which is a Mongolian gerbil model that has been reported as an optimal laboratory animal model to study H pylori.Pregnant Mongolian gerbils, infected experimentally with H pylori, were divided into as four groups. Following the experimental design, the stomachs of the mother and litters were isolated and assessed for transmission of H pylori at the prenatal period, parturition day, 1-wk old and 3-wk old respectively. Bacterial culture and polymerase chain reaction (PCR) were used to examine the presence of transmitted H pylori.RESULTS: All litters showed no transmission of H pylori during pregnancy and at parturition day. However, they revealed 33.3% and 69.6% at 1-wk and 3-wk of age respectively by PCR.CONCLUSION: These results suggested that vertical infection during the prenatal period or delivery procedure is unlikely as a route of mother-to-child H pylori infection.It may be that H pylori is acquired through breastfeeding, contaminated saliva and fecal-oral transmission during co-habitation.

  14. Characterization of HIV Transmission in South-East Austria.

    Science.gov (United States)

    Hoenigl, Martin; Chaillon, Antoine; Kessler, Harald H; Haas, Bernhard; Stelzl, Evelyn; Weninger, Karin; Little, Susan J; Mehta, Sanjay R

    2016-01-01

    To gain deeper insight into the epidemiology of HIV-1 transmission in South-East Austria we performed a retrospective analysis of 259 HIV-1 partial pol sequences obtained from unique individuals newly diagnosed with HIV infection in South-East Austria from 2008 through 2014. After quality filtering, putative transmission linkages were inferred when two sequences were ≤1.5% genetically different. Multiple linkages were resolved into putative transmission clusters. Further phylogenetic analyses were performed using BEAST v1.8.1. Finally, we investigated putative links between the 259 sequences from South-East Austria and all publicly available HIV polymerase sequences in the Los Alamos National Laboratory HIV sequence database. We found that 45.6% (118/259) of the sampled sequences were genetically linked with at least one other sequence from South-East Austria forming putative transmission clusters. Clustering individuals were more likely to be men who have sex with men (MSM; pAustria had at least one putative inferred linkage with sequences from a total of 69 other countries. In conclusion, analysis of HIV-1 sequences from newly diagnosed individuals residing in South-East Austria revealed a high degree of national and international clustering mainly within MSM. Interestingly, we found that a high number of heterosexual males clustered within MSM networks, suggesting either linkage between risk groups or misrepresentation of sexual risk behaviors by subjects.

  15. APEnet+ 34 Gbps data transmission system and custom transmission logic

    Science.gov (United States)

    Ammendola, R.; Biagioni, A.; Frezza, O.; Lonardo, A.; Lo Cicero, F.; Paolucci, P. S.; Rossetti, D.; Simula, F.; Tosoratto, L.; Vicini, P.

    2013-12-01

    APEnet+ is a point-to-point, low-latency, 3D-torus network controller integrated in a PCIe Gen2 board based on the Altera Stratix IV FPGA. We characterize the transmission system (embedded transceivers driving external QSFP+ modules) analyzing signal integrity, throughput, latency, BER and jitter at different data rates up to 34 Gbps. We estimate the efficiency of a custom logic able to sustain 2.6 GB/s per link with an FPGA on-chip memory footprint of 40 KB, providing deadlock-free routing and systemic awareness of faults. Finally, we show the preliminary results obtained with the embedded transceivers of a next-generation FPGA and outline some ideas to increase the performance with the same FPGA memory footprint.

  16. Transmission Dynamics of a Driven Two-Level System Dissipated by Leads

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping; FAN Wen-Bin; ZHAO Xian-Geng

    2001-01-01

    We study the transmission dynamics of a driven two-level system dissipated by the two leads. Using the nonequilibrium Green function, we derive an analytical transmission formula for an electron incident from the left lead,through the double quantum dots, to the right lead. The Landauer-type conductance and current are also given.A discussion of the internal tunnelling dynamics reveals crucial effects of the localization and delocalization on the transport of the system.

  17. Topics in Electricity Transmission Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerndal, Mette

    2000-02-01

    Within the last decade we have experienced deregulation of several industries, such as airlines, telecommunications and the electric utility industry, the last-mentioned being the focus of this work. Both the telecommunications and the electricity sector depend on network facilities, some of which are still considered as natural monopolies. In these industries, open network access is regarded as crucial in order to achieve the gains from increased competition, and transmission tariffs are important in implementing this. Based on the Energy Act that was introduced in 1991, Norway was among the first countries to restructure its electricity sector. On the supply side there are a large number of competing firms, almost exclusively hydro plants, with a combined capacity of about 23000 MW, producing 105-125 TWh per year, depending on the availability of water. Hydro plants are characterized by low variable costs of operation, however since water may be stored in dams, water has an opportunity cost, generally known as the water value, which is the shadow price of water when solving the generator's inter temporal profit maximization problem. Water values are the main factor of the producers' short run marginal cost. Total consumption amounts to 112-117 TWh a year, and consumers, even households, may choose their electricity supplier independent of the local distributor to which the customer is connected. In fact, approximately 10% of the households have actually changed supplier. The web-site www.konkurransetilsynet.no indicates available contracts, and www.dinside.no provides an ''energy-calculator'' where one can check whether it is profitable to switch supplier. If a customer buys energy from a remote supplier, the local distributor only provides transportation facilities for the energy and is compensated accordingly. Transmission and distribution have remained monopolized and regulated by the Norwegian Water Resources and Energy

  18. Topics on Electricity Transmission Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerndal, Mette

    2000-02-01

    Within the last decade we have experienced deregulation of several industries, such as airlines, telecommunications and the electric utility industry, the last-mentioned being the focus of this work. Both the telecommunications and the electricity sector depend on network facilities, some of which are still considered as natural monopolies. In these industries, open network access is regarded as crucial in order to achieve the gains from increased competition, and transmission tariffs are important in implementing this. Based on the Energy Act that was introduced in 1991, Norway was among the first countries to restructure its electricity sector. On the supply side there are a large number of competing firms, almost exclusively hydro plants, with a combined capacity of about 23000 MW, producing 105-125 TWh per year, depending on the availability of water. Hydro plants are characterized by low variable costs of operation, however since water may be stored in dams, water has an opportunity cost, generally known as the water value, which is the shadow price of water when solving the generator's inter temporal profit maximization problem. Water values are the main factor of the producers' short run marginal cost. Total consumption amounts to 112-117 TWh a year, and consumers, even households, may choose their electricity supplier independent of the local distributor to which the customer is connected. In fact, approximately 10% of the households have actually changed supplier. The web-site www.konkurransetilsynet.no indicates available contracts, and www.dinside.no provides an ''energy-calculator'' where one can check whether it is profitable to switch supplier. If a customer buys energy from a remote supplier, the local distributor only provides transportation facilities for the energy and is compensated accordingly. Transmission and distribution have remained monopolized and regulated by the Norwegian Water Resources and Energy

  19. Transmission of equine influenza virus during an outbreak is characterized by frequent mixed infections and loose transmission bottlenecks.

    Directory of Open Access Journals (Sweden)

    Joseph Hughes

    2012-12-01

    Full Text Available The ability of influenza A viruses (IAVs to cross species barriers and evade host immunity is a major public health concern. Studies on the phylodynamics of IAVs across different scales - from the individual to the population - are essential for devising effective measures to predict, prevent or contain influenza emergence. Understanding how IAVs spread and evolve during outbreaks is critical for the management of epidemics. Reconstructing the transmission network during a single outbreak by sampling viral genetic data in time and space can generate insights about these processes. Here, we obtained intra-host viral sequence data from horses infected with equine influenza virus (EIV to reconstruct the spread of EIV during a large outbreak. To this end, we analyzed within-host viral populations from sequences covering 90% of the infected yards. By combining gene sequence analyses with epidemiological data, we inferred a plausible transmission network, in turn enabling the comparison of transmission patterns during the course of the outbreak and revealing important epidemiological features that were not apparent using either approach alone. The EIV populations displayed high levels of genetic diversity, and in many cases we observed distinct viral populations containing a dominant variant and a number of related minor variants that were transmitted between infectious horses. In addition, we found evidence of frequent mixed infections and loose transmission bottlenecks in these naturally occurring populations. These frequent mixed infections likely influence the size of epidemics.

  20. Virus-phytoplankton adhesion: a new WSSV transmission route to zooplankton

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pathogenicity of white spot syndrome virus (WSSV) to zooplankton species, rotifer Brachionus urceus (Linnaeus), copepod Acartia clausi (Giesbrecht) and mysid shrimp Neomysis awatschensis (Brandt), was estimated by immersion challenge and virus-phytoplankton adhesion route to investigate a potential new transmission route of WSSV to zooplankton. WSSV succeeded in infecting these zooplankton species and nested-PCR revealed positive results for the virus-phytoplankton adhesion route, whereas WSSV cannot infect zooplankton by immersion challenge. These results indicated that virus-phytoplankton adhesion route is a successful new transmission route of WSSV to zooplankton and also implied that phytoplankton could be a carrier in WSSV transmission.

  1. Enhancement and Inhibition of Transmission from metal gratings: Engineering the Spectral Response

    CERN Document Server

    de Ceglia, D; Scalora, M; Akozbek, N; Bloemer, M J

    2010-01-01

    We present a systematic analysis of the optical properties of slit arrays in metal films. An exhaustive investigation of geometrical and dispersive properties reveals the resonance features of these structures, including the role of surface waves and their relationship with features in the transmission spectrum. Although enhanced transmission windows are significantly dominated by the longitudinal resonances localized inside the slits, the periodicity introduces transverse resonances that can either enhance or inhibit light transmission. We thus illustrate the intriguing interaction regime between longitudinal and transverse resonances, where the two modes hybridize leading to the formation of a photonic band gap spectrum.

  2. Resonant Transmission of Electromagnetic Fields through Subwavelength Zero-$\\epsilon$ Slits

    CERN Document Server

    Halterman, Klaus

    2008-01-01

    We theoretically investigate the transmission of electromagnetic radiation through a metal plate with a zero-$\\epsilon$ metamaterial slit, where the permittivity tends towards zero over a given bandwidth. Our analytic results demonstrate that the transmission coefficient can be substantial for a broad range of slit geometries, including subwavelength widths that are many wavelengths long. This novel resonant effect has features quite unlike the Fabry-P\\'{e}rot-like resonances that have been observed in conductors with deep channels. We further reveal that these high impedance ultranarrow zero-$\\epsilon$ channels can have significantly {\\it greater} transmission compared to slits with no wave impedance difference across them.

  3. Electrophysiology of autonomic neuromuscular transmission involving ATP.

    Science.gov (United States)

    Sneddon, P

    2000-07-01

    Electrophysiological investigations of autonomic neuromuscular transmission have provided great insights into the role of ATP as a neurotransmitter. Burnstock and Holman made the first recordings of excitatory junction potentials (e.j.p.s) produced by sympathetic nerves innervating the smooth muscle of the guinea-pig vas deferens. This led to the identification of ATP as the mediator of e.j.p.s in this tissue, where ATP acts as a cotransmitter with noradrenaline. The e.j.p.s are mediated solely by ATP acting on P2X(1) receptors leading to action potentials and a rapid phasic contraction, whilst noradrenaline mediates a slower, tonic contraction which is not dependent on membrane depolarisation. Subsequent electrophysiological studies of the autonomic innervation of smooth muscles of the urogenital, gastrointestinal and cardiovascular systems have revealed a similar pattern of response, where ATP mediates a fast electrical and mechanical response, whilst another transmitter such as noradrenaline, acetylcholine, nitric oxide or a peptide mediates a slower response. The modulation of junction potentials by a variety of pre-junctional receptors and the mechanism of inactivation of ATP as a neurotransmitter will also be described.

  4. Inter-generational transmission of incest.

    Science.gov (United States)

    Cooper, I; Cormier, B M

    1982-04-01

    The majority of reported incest cases involve sexual relations between one generation and another, the most common being father-daughter incest. The increased availability of clinical data on incest has revealed an aspect of the problem that has received little attention in clinical literature. Incest can involve three generations in a family rather than two. It is possible for incest to be "transmitted" from one generation to the next through several patterns. In some cases, the mother in a family of father-daughter incest has herself been a victim of incest with her own father. With a history of unresolved incest with their own fathers, these women are unable to prevent an incest relationship between their husbands and daughters. Another pattern involves situations where the father in the father-daughter incest relationship has been the victim of father-son incest in his youth. The psychodynamics of these patterns of intergenerational transmission of incest are described, with clinical examples from the authors' work, as well as from the literature.

  5. 伯氏疟原虫再感染过程中树突状细胞表面分子表达水平的实验观察%Experimental observation on expression levels of dendritic cell surface molecular during the course of reinfection with Plasmodium berghei ANKA

    Institute of Scientific and Technical Information of China (English)

    刘英杰; 潘艳艳; 李莹; 冯永辉; 刘军; 曹雅明

    2011-01-01

    To investigate effect of radical treatment in early phase of primary infection with Plsamodium spp.on expression levels of dendritic cells (DCs) surface molecular during the course of reinfection.DBA/2 mice were infected by intraperitoneal injection of 1 × 106 P.berghei ANKA (PbA) parasited erythrocytes, and radically treated with chloroquine plus artesunate on day 3 after infection.Then the mice were reinfected with PbA on day 90 after primary infection.The level of parasitemia during primary and secondary infections was observed by mean of the Giemsa staining of thin blood smears.Flow cytometry was appilied to quantitively analyze the percentage of CD11c+ CD80+ DCs, CD11c+ CD86+ DCs, CD11c+ CD40+ DCs, CD11c+MHC-Ⅱ+ DCs and actived T cells in spleen cell population on days 0, 1 ,3 and 5 post-reinfection, respectively.It was found that parasitemia in radically treated mice post-reinfection was transient and extremely low, and the percentage of CD11c+CD80+ DCs, CD11c+ CD86+ DCs, CD11c+ CD40+ DCs and CD11c+ MHC-Ⅱ+ DCs in spleen cell population from the mice organ all to increase on day 3 post-reinfection.Moreover, the percentage of actived T cells began to rise steadily from day 1 to day 5 after reinfection.These results suggest that homologous malarial parasite rechallenge could induce DCs to mature and fully functional display after radical treatment in early phase of primary infection with Plasmodium spp.%目的 探讨疟疾感染早期根治性治疗对再感染过程中树突状细胞(dendritic cells,DCs)成熟和功能的影响.方法 用伯氏疟原虫(Plasmodium berghei ANKA,PbA)感染DBA/2小鼠,感染后3d进行根治性治疗,并于初次感染后90d进行再感染.通过吉姆萨薄血膜染色法计数红细胞感染率,流式细胞术检测再感染前(0d)和再感染后(1d、3d、5d)不同时间点脾细胞中表达CD80、CD86、CD40和MHC-Ⅱ分子的DCs以及活化性T细胞的百分含量.结果 同种疟原虫再感染后,根治性治疗小鼠

  6. Poverty, Policy and Price Transmission

    DEFF Research Database (Denmark)

    Elleby, Christian

    This thesis consists of four self-contained chapters in which different aspects of the relationship between international commodity markets and domestic food markets are explored. What motivates the analysis is the recent surge in international commodity prices and the controversy over the poverty...... domestic goods. Households prefer the traded good which they substitute towards as their incomes increase, thus exposing themselves to world market price swings. Price transmission from international to domestic markets therefore increases with per capita income but also with income inequality. Model...... using a Bayesian simulation methodology. Three main findings emerge from the analysis. Firstly, it seems that domestic rather than global or regional shocks are the main drivers of domestic food prices in all regions. Secondly, global factors have gained importance since 2005. Food inflation...

  7. Multimedia signal coding and transmission

    CERN Document Server

    Ohm, Jens-Rainer

    2015-01-01

    This textbook covers the theoretical background of one- and multidimensional signal processing, statistical analysis and modelling, coding and information theory with regard to the principles and design of image, video and audio compression systems. The theoretical concepts are augmented by practical examples of algorithms for multimedia signal coding technology, and related transmission aspects. On this basis, principles behind multimedia coding standards, including most recent developments like High Efficiency Video Coding, can be well understood. Furthermore, potential advances in future development are pointed out. Numerous figures and examples help to illustrate the concepts covered. The book was developed on the basis of a graduate-level university course, and most chapters are supplemented by exercises. The book is also a self-contained introduction both for researchers and developers of multimedia compression systems in industry.

  8. Magnetically insulated transmission line oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, Larry D. (Albuquerque, NM); Ballard, William P. (Albuquerque, NM); Clark, M. Collins (Albuquerque, NM); Marder, Barry M. (Albuquerque, NM)

    1988-01-01

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields arfe produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap.

  9. Nonlinear transmission of an intense terahertz field through monolayer graphene

    Directory of Open Access Journals (Sweden)

    H. A. Hafez

    2014-11-01

    Full Text Available We report nonlinear terahertz (THz effects in monolayer graphene, giving rise to transmission enhancement of a single-cycle THz pulse when the incident THz peak electric field is increased. This transmission enhancement is attributed to reduced photoconductivity, due to saturation effects in the field-induced current and increased intraband scattering rates arising from transient heating of electrons. We have developed a tight-binding model of the response using the length gauge interaction Hamiltonian that provides good qualitative agreement. The model fully accounts for the nonlinear response arising from the linear dispersion energy spectrum in graphene. The results reveal a strong dependence of the scattering time on the THz field, which is at the heart of the observed nonlinear response.

  10. International Transmission of Shocks and Fragility of a Bank Network

    CERN Document Server

    Feng, Xiaobing; Kim, Beom Jun

    2014-01-01

    The weighted and directed network of countries based on the number of overseas banks is analyzed in terms of its fragility to the banking crisis of one country. We use two different models to describe transmission of shocks, one local and the other global. Depending on the original source of the crisis, the overall size of crisis impacts is found to differ country by country. For the two-step local spreading model, it is revealed that the scale of the first impact is determined by the out-strength, the total number of overseas branches of the country at the origin of the crisis, while the second impact becomes more serious if the in-strength at the origin is increased. For the global spreading model, some countries named "triggers" are found to play important roles in shock transmission, and the importance of the feed-forward-loop mechanism is pointed out. We also discuss practical policy implications of the present work.

  11. An extraordinary transmission analogue for enhancing microwave antenna performance

    Directory of Open Access Journals (Sweden)

    Sarin V. Pushpakaran

    2015-10-01

    Full Text Available The theory of diffraction limit proposed by H.A Bethe limits the total power transfer through a subwavelength hole. Researchers all over the world have gone through different techniques for boosting the transmission through subwavelength holes resulting in the Extraordinary Transmission (EOT behavior. We examine computationally and experimentally the concept of EOT nature in the microwave range for enhancing radiation performance of a stacked dipole antenna working in the S band. It is shown that the front to back ratio of the antenna is considerably enhanced without affecting the impedance matching performance of the design. The computational analysis based on Finite Difference Time Domain (FDTD method reveals that the excitation of Fabry-Perot resonant modes on the slots is responsible for performance enhancement.

  12. An extraordinary transmission analogue for enhancing microwave antenna performance

    Energy Technology Data Exchange (ETDEWEB)

    Pushpakaran, Sarin V., E-mail: sarincrema@gmail.com [Department of Electronics, Govt. College, Chittur, Palakkad, Kerala (India); Purushothaman, Jayakrishnan M.; Chandroth, Aanandan; Pezholil, Mohanan; Kesavath, Vasudevan [Centre for Research in Electromagnetics and Antennas, Cochin University of Science and Technology, Cochin-22, Kerala (India)

    2015-10-15

    The theory of diffraction limit proposed by H.A Bethe limits the total power transfer through a subwavelength hole. Researchers all over the world have gone through different techniques for boosting the transmission through subwavelength holes resulting in the Extraordinary Transmission (EOT) behavior. We examine computationally and experimentally the concept of EOT nature in the microwave range for enhancing radiation performance of a stacked dipole antenna working in the S band. It is shown that the front to back ratio of the antenna is considerably enhanced without affecting the impedance matching performance of the design. The computational analysis based on Finite Difference Time Domain (FDTD) method reveals that the excitation of Fabry-Perot resonant modes on the slots is responsible for performance enhancement.

  13. Geometric and Meshing Properties of Conjugate Curves for Gear Transmission

    Directory of Open Access Journals (Sweden)

    Dong Liang

    2014-01-01

    Full Text Available Conjugate curves have been put forward previously by authors for gear transmission. Compared with traditional conjugate surfaces, the conjugate curves have more flexibility and diversity in aspects of gear design and generation. To further extend its application in power transmission, the geometric and meshing properties of conjugate curves are discussed in this paper. Firstly, general principle descriptions of conjugate curves for arbitrary axial position are introduced. Secondly, geometric analysis of conjugate curves is carried out based on differential geometry including tangent and normal in arbitrary contact direction, characteristic point, and curvature relationships. Then, meshing properties of conjugate curves are further revealed. According to a given plane or spatial curve, the uniqueness of conjugated curve under different contact angle conditions is discussed. Meshing commonality of conjugate curves is also demonstrated in terms of a class of spiral curves contacting in the given direction for various gear axes. Finally, a conclusive summary of this study is given.

  14. Point of Connection Transmission Pricing in India

    Science.gov (United States)

    Soonee, S. K.; Barpanda, S. S.; Joshi, Mohit; Mishra, Nripen; Bhardwaj, Vaishally

    2013-05-01

    The National Electricity Policy (NEP) [1], issued by the Government of India, mandates transmission prices to be distance and direction sensitive and capture utilization of the network by each network user. In line with the mandate, the Central Electricity Regulatory Commission (CERC) [2] has issued Sharing of Interstate Transmission Charges and Losses Regulations, 2010 [3], to introduce point of connection (PoC)-based transmission pricing methodology in India. The methodology under the above regulations introduces one of the major reforms of its kind in the Indian power sector and seeks to share the total transmission charges in proportion to respective utilization of the transmission system by different entities. In this paper, the authors have enumerated their experience gained from the implementation of PoC-based transmission pricing regime in India. Authors have also discussed various issues encountered in the process of implementation and the methodology adopted.

  15. Inference of Transmission Network Structure from HIV Phylogenetic Trees

    Science.gov (United States)

    Britton, Tom; Leitner, Thomas

    2017-01-01

    Phylogenetic inference is an attractive means to reconstruct transmission histories and epidemics. However, there is not a perfect correspondence between transmission history and virus phylogeny. Both node height and topological differences may occur, depending on the interaction between within-host evolutionary dynamics and between-host transmission patterns. To investigate these interactions, we added a within-host evolutionary model in epidemiological simulations and examined if the resulting phylogeny could recover different types of contact networks. To further improve realism, we also introduced patient-specific differences in infectivity across disease stages, and on the epidemic level we considered incomplete sampling and the age of the epidemic. Second, we implemented an inference method based on approximate Bayesian computation (ABC) to discriminate among three well-studied network models and jointly estimate both network parameters and key epidemiological quantities such as the infection rate. Our ABC framework used both topological and distance-based tree statistics for comparison between simulated and observed trees. Overall, our simulations showed that a virus time-scaled phylogeny (genealogy) may be substantially different from the between-host transmission tree. This has important implications for the interpretation of what a phylogeny reveals about the underlying epidemic contact network. In particular, we found that while the within-host evolutionary process obscures the transmission tree, the diversification process and infectivity dynamics also add discriminatory power to differentiate between different types of contact networks. We also found that the possibility to differentiate contact networks depends on how far an epidemic has progressed, where distance-based tree statistics have more power early in an epidemic. Finally, we applied our ABC inference on two different outbreaks from the Swedish HIV-1 epidemic. PMID:28085876

  16. Research on stepless transmission utilizing noncircular gears

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmiss...

  17. Puerto Rico Revealed Preference data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Revealed preference models provide insights into recreational angler behavior and the economic value of recreational fishing trips. Revealed preference data is...

  18. Transmission eigenvalues for operators with constant coefficients

    CERN Document Server

    Hitrik, Michael; Ola, Petri; Päivärinta, Lassi

    2010-01-01

    In this paper we study the interior transmission problem and transmission eigenvalues for multiplicative perturbations of linear partial differential operator of order $\\ge 2$ with constant real coefficients. Under suitable growth conditions on the symbol of the operator and the perturbation, we show the discreteness of the set of transmission eigenvalues and derive sufficient conditions on the existence of transmission eigenvalues. We apply these techniques to the case of the biharmonic operator and the Dirac system. In the hypoelliptic case we present a connection to scattering theory.

  19. Study of Transmission Loss on Muffler

    Directory of Open Access Journals (Sweden)

    Wang Bing

    2013-05-01

    Full Text Available Transmission loss is the main method which measure silencer sound deadening capacity. The most effective noise elimination technique of compensator is muffler. Muffler is equipment which organizes sound transmission and permits airflow pass and must satisfy definite muffling amount and frequency property. The study builds model and theoretically studies and analyzes the internal sound problem and contrasts between FEM and transmission matrix method and computes transmission loss. On the basis of experimental verification, combining model analysis with sound pressure distribution graph, analyze muffling property deeply.

  20. Overvoltage Suppression for UHV Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    LI Yongli; LIU Taihua; LI Zhongqing; JING Lei; LONG Ying; FAN Jianzhong

    2008-01-01

    The overvoltage phenomena of ultra high voltage (UHV) transmission lines are analyzed and verified by EMTDC/PSCAD simulation. Referring to the theoretical analyses and operating experiences of extra high voltage (EHV) transmission lines in China and UHV transmission lines in Russia and Japan, the methods to suppress the internal overvoltage in UHV transmission lines by protection and control strategies are discussed. Through the cooperation among the recloser, shunt reactor, tripping and closing resistance, and metal oxide varistor (MOV), the overvoltage can be restrained within an acceptable level.

  1. Cross-species transmission of CWD prions.

    Science.gov (United States)

    Kurt, Timothy D; Sigurdson, Christina J

    2016-01-01

    Prions cause fatal neurodegenerative diseases in humans and animals and can be transmitted zoonotically. Chronic wasting disease (CWD) is a highly transmissible prion disease of wild deer and elk that affects cervids over extensive regions of the United States and Canada. The risk of cross-species CWD transmission has been experimentally evaluated in a wide array of mammals, including non-human primates and mouse models expressing human cellular prion protein. Here we review the determinants of cross-species CWD transmission, and propose a model that may explain a structural barrier for CWD transmission to humans.

  2. Transmission Line Security Monitor: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    John Svoboda

    2011-04-01

    The Electric Power Transmission Line Security Monitor System Operational Test is a project funded by the Technical Support Working Group (TSWG). TSWG operates under the Combating Terrorism Technical Support Office that functions under the Department of Defense. The Transmission Line Security Monitor System is based on technology developed by Idaho National Laboratory. The technology provides a means for real-time monitoring of physical threats and/or damage to electrical transmission line towers and conductors as well as providing operational parameters to transmission line operators to optimize transmission line operation. The end use is for monitoring long stretches of transmission lines that deliver electrical power from remote generating stations to cities and industry. These transmission lines are generally located in remote transmission line corridors where security infrastructure may not exist. Security and operational sensors in the sensor platform on the conductors take power from the transmission line and relay security and operational information to operations personnel hundreds of miles away without relying on existing infrastructure. Initiated on May 25, 2007, this project resulted in pre-production units tested in realistic operational environments during 2010. A technology licensee, Lindsey Manufacturing of Azusa California, is assisting in design, testing, and ultimately production. The platform was originally designed for a security monitoring mission, but it has been enhanced to include important operational features desired by electrical utilities.

  3. Random torsional vibration in automobile transmissions

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The action of a road profile to the torsional vibrations in automobile transmissions is studied. The model to calculate the random torsional vibrations in the transmissions is proposed and the values of the model parameters are determined by both computation and experiment. Furthermore, the dynamic characteristics and the responses of automobile transmissions to the random excitation of road profile are calculated. The results of road experiment demonstrate that the theoretic analyses and the calculation are correct, which imply that the low frequency torsional vibrations in automobile transmissions are caused by the random excitation of a road profile.

  4. Revealing the Beast Within

    Science.gov (United States)

    2003-07-01

    Deeply Embedded Massive Stellar Clusters Discovered in Milky Way Powerhouse Summary Peering into a giant molecular cloud in the Milky Way galaxy - known as W49 - astronomers from the European Southern Observatory (ESO) have discovered a whole new population of very massive newborn stars . This research is being presented today at the International Astronomical Union's 25th General Assembly held in Sydney, Australia, by ESO-scientist João Alves. With the help of infrared images obtained during a period of excellent observing conditions with the ESO 3.5-m New Technology Telescope (NTT) at the La Silla Observatory (Chile), the astronomers looked deep into this molecular cloud and discovered four massive stellar clusters, with hot and energetic stars as massive as 120 solar masses. The exceedingly strong radiation from the stars in the largest of these clusters is "powering" a 20 light-year diameter region of mostly ionized hydrogen gas (a "giant HII region"). W49 is one of the most energetic regions of star formation in the Milky Way. With the present discovery, the true sources of the enormous energy have now been revealed for the first time, finally bringing to an end some decades of astronomical speculations and hypotheses. PR Photo 21a/03 : Colour Composite of W49A (NTT+SOFI). PR Photo 21b/03 : Radio and Near-Infrared Composite of W49A Giant molecular clouds Stars form predominantly inside Giant Molecular Clouds which populate our Galaxy, the Milky Way. One of the most prominent of these is W49 , which has a mass of a million solar masses. It is located some 37,000 light-years away and is the most luminous star-forming region known in our home galaxy: its luminosity is several million times the luminosity of our Sun. A smaller region within this cloud is denoted W49A - this is one of the strongest radio-emitting areas known in the Galaxy . Massive stars are excessive in all ways. Compared to their smaller and ligther brethren, they form at an Olympic speed and

  5. Transmission Lines or Poles, Electric, electric transmission line, Published in unknown, Kleinschmidt.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Transmission Lines or Poles, Electric dataset as of unknown. It is described as 'electric transmission line'. Data by this publisher are often provided in UTM...

  6. Transmission of Helicobacter pylori Infection

    Directory of Open Access Journals (Sweden)

    Giuseppina Oderda

    1999-01-01

    Full Text Available Helicobacter pylori infection is one of the most common bacterial infections worldwide. It is accepted as the major cause of chronic gastritis, peptic ulcer, carcinoma of the distal part of the stomach and gastric lymphoma. However, how and when the infection is acquired remain largely unknown. Identification of mode of transmission is vital for developing preventive measures to interrupt its spread, but studies focused on this issue are difficult to implement. From epidemiological studies, it is known that there are great differences in the prevalence of infection in different populations and in ethnic groups originating from high prevalence regions. This is likely related to inferior hygienic conditions and sanitation. In developing countries, infection occurs at a much earlier age. In developed countries, the prevalence of infection is related to poor socioeconomic conditions, particularly density of living. Humans seem to be the only reservoir of H pylori, which spread from person to person by oral-oral, fecal-oral or gastro-oral routes. Most infections are acquired in childhood, possibly from parents or other children living as close contacts. Infection from the environment or from animals cannot be entirely excluded.

  7. Seir Model for Transmission of Dengue Fever in Selangor Malaysia

    Science.gov (United States)

    Syafruddin, S.; Noorani, M. S. M.

    In this paper, we study a system of differential equations that models the population dynamics of SEIR vector transmission of dengue fever. The model studied breeding value based on the number of reported cases of dengue fever in Selangor because the state had the highest case in Malaysia. The model explains that maximum level of human infection rate of dengue fever achieved in a very short period. It is also revealed that there existed suitability result between theoretical and empirical calculation using the model. The result of SEIR model will hopefully provide an insight into the spread of dengue fever in Selangor Malaysia and basic form for modeling this area.

  8. Metallocarbohedrenes: Transmission Electron Microscopy of Mass Gated Deposits

    Science.gov (United States)

    Castleman, M. E. Lyn, Jr.

    2002-03-01

    Titanium and zirconium Met-Car cluster ions have been detected from the direct laser vaporization of metal-graphite mixtures using time-of-flight mass spectrometry. Optimization of the production conditions enabled sufficient intensities to mass select and deposit Met-Cars on surfaces. High-resolution transmission electron microscopy images of mass gated Met-Car species reveals deposited nanocrystals 2 nm in diameter. Diffraction patterns indicate the presence of multiple species and shows that the deposits have spatial orientation. Lattice parameters have been extracted. The implication of the findings will be discussed. Support for the work has been from the AFOSR F49620-01-1-0122.

  9. In situ and operando transmission electron microscopy of catalytic materials

    DEFF Research Database (Denmark)

    Crozier, Peter A.; Hansen, Thomas Willum

    2015-01-01

    Catalytic nanomaterials play a major role in chemical conversions and energy transformations. Understanding how materials control and regulate surface reactions is a major objective for fundamental research on heterogeneous catalysts. In situ environmental transmission electron microscopy (ETEM......) is a powerful technique for revealing the atomic structures of materials at elevated temperatures in the presence of reactive gases. This approach can allow the structure-reactivity relations underlying catalyst functionality to be investigated. Thus far, ETEM has been limited by the absence of in situ...

  10. Spermatogenic transmission of Marbug and ebola virus

    Directory of Open Access Journals (Sweden)

    Sora Yasri

    2015-03-01

    Full Text Available The spermatogenic transmission of infectious disease is an interesting consideration in reproductive medicine. The problem can be serious and classified as sexually transmitted infection. The concern is on the new emerging viral infections because there is usually little information on those new viruses. In this short article, the authors specially review and discuss on Spermatogenic transmission of Marbug and ebola virus.

  11. Transmission dynamics and resistance in staphylococci

    NARCIS (Netherlands)

    Hetem, D.J.

    2015-01-01

    This thesis will focus on nosocomial transmission and resistance of S. aureus and CoNS. After the general introduction on S. aureus and coagulase-negative staphylococci, part II focuses on the nosocomial transmission capacity of different MRSA clones in the hospital setting. In chapter 2 the nosocom

  12. Gear Transmission Error Measurement System Made Operational

    Science.gov (United States)

    Oswald, Fred B.

    2002-01-01

    A system directly measuring the transmission error between the meshing spur or helical gears was installed at the NASA Glenn Research Center and made operational in August 2001. This system employs light beams directed by lenses and prisms through gratings mounted on the two gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. The device is capable of resolution better than 0.1 mm (one thousandth the thickness of a human hair). The measured transmission error can be displayed in a "map" that shows how the transmission error varies with the gear rotation or it can be converted to spectra to show the components at the meshing frequencies. Accurate transmission error data will help researchers better understand the mechanisms that cause gear noise and vibration and will lead to The Design Unit at the University of Newcastle in England specifically designed the new system for NASA. It is the only device in the United States that can measure dynamic transmission error at high rotational speeds. The new system will be used to develop new techniques to reduce dynamic transmission error along with the resulting noise and vibration of aeronautical transmissions.

  13. Dual-Rate Transmission Reduces Weather Effects

    Science.gov (United States)

    Posner, E. C.

    1984-01-01

    Scheme ensures maximum data received on average. Dual-rate scheme for maximizing data returned during spacecraft mission, adaptable, as is or with modifications, to high-frequency terrestrial data transmission. Data rate fixed in advance at minimum value guarantees reasonable prospect of success during bad weather. Dualrate strategy yields net data rate 2.5 times best achievable with single transmission rate.

  14. Sexual and vertical transmission of visceral leishmaniasis.

    Science.gov (United States)

    Turchetti, Andreia P; Souza, Tayse D; Paixão, Tatiane A; Santos, Renato L

    2014-04-15

    Visceral leishmaniasis (VL) is an important zoonosis caused by Leishmania infantum, which has in the domestic dog its principal vertebrate host. VL is usually transmitted by phlebotomine sand flies, however atypical routes of transmission have been described. In this review we discuss the the role of sexual and vertical transmissions, and their role in the maintenance of VL in canine populations.

  15. Investment in electricity networks with transmission switching

    DEFF Research Database (Denmark)

    Villumsen, Jonas Christoffer; Philpott, A.B.

    2012-01-01

    We consider the application of Dantzig-Wolfe decomposition to stochastic integer programming problems arising in the capacity planning of electricity transmission networks that have some switchable transmission elements. The decomposition enables a column-generation algorithm to be applied, which...

  16. Spermatogenic transmission of Marbug and ebola virus

    Institute of Scientific and Technical Information of China (English)

    Sora Yasri; Viroj Wiwanitkit

    2015-01-01

    The spermatogenic transmission of infectious disease is an interesting consideration in reproductive medicine. The problem can be serious and classified as sexually transmitted infection. The concern is on the new emerging viral infections because there is usually little information on those new viruses. In this short article, the authors specially review and discuss on Spermatogenic transmission of Marbug and ebola virus.

  17. Transmission Lines in CMOS: An Explorative Study

    NARCIS (Netherlands)

    Klumperink, E.A.M.; Kreienkamp, R.; Ellermeyer, T.; Langmann, U.

    2001-01-01

    On-chip transmission line modelling and design become increasingly important as frequencies are continuously going up. This paper explores possibilities to implement transmission lines on CMOS ICs via coupled coplanar strips. EM-field simulations with SONNET are used to estimate important transmissi

  18. Methicillin-resistant Staphylococcus aureus transmission

    DEFF Research Database (Denmark)

    Andersen, Leif Percival; Nielsen, Xiaohui

    2015-01-01

    INTRODUCTION: Even though methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infections, it may often be difficult to evaluate the exact route of transmission. METHODS: In this study, we describe four cases of nosocomial transmission of MRSA in a hospital with a low...

  19. Advanced Rotorcraft Transmission (ART) Program summary

    Science.gov (United States)

    Krantz, T. L.; Kish, J. G.

    1992-07-01

    The Advanced Rotorcraft Transmission (ART) Program was initiated to advance the state of the art for rotorcraft transmissions. The goal of the ART Program was to develop and demonstrate the technologies needed to reduce transmission weight by 25 pct and reduce noise by 10 dB while obtaining a 5000 hr 'mean time between failure'. The research done under the ART Program is summarized. A split path design was selected as best able to meet the program goals. Key part technologies needed for this design were identified, studied, and developed. Two of these technologies are discussed in detail: the load sharing of split path designs including the use of a compliant elastomeric torque splitter and the application of a high ratio, low pitch line velocity gear mesh. Development of an angular contact spherical roller bearing, transmission error analysis, and fretting fatigue testing are discussed. The technologies for a light weight, quiet, and reliable rotorcraft transmission were demonstrated.

  20. Advanced Rotorcraft Transmission (ART) program status

    Science.gov (United States)

    Bossler, Robert; Heath, Gregory

    1991-01-01

    Reported herein is work done on the Advanced Rotorcraft Transmission by McDonnell Douglas Helicopter Company under Army/NASA contract. The novel concept pursued includes the use of face gears for power transmission and a torque splitting arrangement. The design reduces the size and weight of the corner-turning hardware and the next reduction stage. New methods of analyzing face gears have increased confidence in their usefulness. Test gears have been designed and manufactured for power transmission testing on the NASA-Lewis spiral bevel test rig. Transmission design effort has included finite element modeling of the split torque paths to assure equal deflection under load. A finite element model of the Apache main transmission has been completed to substantiate noise prediction methods. A positive engagement overrunning clutch design is described. Test spur gears have been made by near-net-shape forging from five different materials. Three housing materials have been procured for evaluation testing.

  1. Unpredictability and the transmission of numbers

    CERN Document Server

    Myers, John M

    2015-01-01

    Curiously overlooked in physics is its dependence on the transmission of numbers. For example the transmission of numerical clock readings is implicit in the concept of a coordinate system. The transmission of numbers and other logical distinctions is often achieved over a computer-mediated communications network in the face of an unpredictable environment. By unpredictable we mean something stronger than the spread of probabilities over given possible outcomes, namely an opening to unforeseeable possibilities. Unpredictability, until now overlooked in theoretical physics, makes the transmission of numbers interesting. Based on recent proofs within quantum theory that provide a theoretical foundation to unpredictability, here we show how regularities in physics rest on a background of channels over which numbers are transmitted. As is known to engineers of digital communications, numerical transmissions depend on coordination reminiscent of the cycle of throwing and catching by players tossing a ball back and...

  2. Transmission properties of cryogenic twisted pair filters

    Energy Technology Data Exchange (ETDEWEB)

    Song, Woon; Rehman, Mushtaq; Chong, Yonuk [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Ryu, Sangwan [Chonnam National University, Gwangju (Korea, Republic of)

    2010-12-15

    We fabricated a cryogenic low pass filter that consists of twisted pairs of manganin wires wrapped in copper tape and measured its transmission characteristics at frequencies up to 18 GHz. The dependence of the microwave transmission characteristics on the filter length was studied, which showed that a filter of length 1.0 m had a 70-dB attenuation at 1 GHz. We also studied the dependence of common- and differential-mode transmission on the number of twists per unit length and found that the number of twists per unit length affects differential-mode transmission but not common-mode transmission. Because the shielded twisted pair filter is more compact than a conventional copper powder filter, it can solve the space and thermal load issues when many cables are required for precision electronic transport experiments at low temperatures.

  3. Occurrence and seasonal transmission of hematozoa in wild turkeys.

    Science.gov (United States)

    Stacey, L M; Couvillion, C E; Siefker, C; Hurst, G A

    1990-10-01

    The occurrence and seasonal patterns of transmission of the blood protozoa of wild turkeys (Meleagris gallopavo silvestris) were studied at Tallahala Wildlife Management Area (TWMA) (Jasper County, Mississippi, USA). Blood smears obtained from wild turkeys in winter, spring and summer, and from sentinel domestic turkeys throughout the year were examined for Haemoproteus meleagridis and Leucocytozoon smithi. Whole blood from wild turkeys captured in summer was subinoculated into malaria-free domestic turkey poults and recipient birds were examined for Plasmodium spp. The prevalence of H. meleagridis and L. smithi were not different (P greater than 0.05) between adults and juveniles or between male and female turkeys in any season. Leucocytozoon smithi was not detected in poults in summer or in juveniles examined in winter. Sentinel studies and information from wild birds revealed that transmission of H. meleagridis and L. smithi did not overlap. Haemoproteus meleagridis was transmitted from May through November, while L. smithi was transmitted only from January through April. The onset of transmission of H. meleagridis coincided with peak hatching (mid-May) and brood-rearing (May-November) of turkey poults. Plasmodium spp. were not found in turkeys from TWMA (n = 27) nor in birds from three widely separated counties (n = 28) in Mississippi.

  4. Normalized power transmission between ABP and ICP in TBI.

    Science.gov (United States)

    Shahsavari, S; Hallen, T; McKelvey, T; Ritzen, C; Rydenhag, B

    2009-01-01

    A new approach to study the pulse transmission between the cerebrovascular bed and the intracranial space is presented. In the proposed approach, the normalized power transmission between ABP and ICP has got the main attention rather than the actual power transmission. Evaluating the gain of the proposed transfer function at any single frequency can reveal how the percentage of contribution of that specific frequency component has been changed through the cerebrospinal system. The gain of the new transfer function at the fundamental cardiac frequency was utilized to evaluate the state of the brain in three TBI patients. Results were assessed using the reference evaluations achieved by a novel CT scan-based scoring scheme. In all three study cases, the gain of the transfer function showed a good capability to follow the trend of the CT scores and describe the brain state. Comparing the new transfer function with the traditional one and also the index of compensatory reserve, the proposed transfer function was found more informative about the state of the brain in the patients under study.

  5. Vector transmission of leishmania abrogates vaccine-induced protective immunity.

    Directory of Open Access Journals (Sweden)

    Nathan C Peters

    2009-06-01

    Full Text Available Numerous experimental vaccines have been developed to protect against the cutaneous and visceral forms of leishmaniasis caused by infection with the obligate intracellular protozoan Leishmania, but a human vaccine still does not exist. Remarkably, the efficacy of anti-Leishmania vaccines has never been fully evaluated under experimental conditions following natural vector transmission by infected sand fly bite. The only immunization strategy known to protect humans against natural exposure is "leishmanization," in which viable L. major parasites are intentionally inoculated into a selected site in the skin. We employed mice with healed L. major infections to mimic leishmanization, and found tissue-seeking, cytokine-producing CD4+ T cells specific for Leishmania at the site of challenge by infected sand fly bite within 24 hours, and these mice were highly resistant to sand fly transmitted infection. In contrast, mice vaccinated with a killed vaccine comprised of autoclaved L. major antigen (ALM+CpG oligodeoxynucleotides that protected against needle inoculation of parasites, showed delayed expression of protective immunity and failed to protect against infected sand fly challenge. Two-photon intra-vital microscopy and flow cytometric analysis revealed that sand fly, but not needle challenge, resulted in the maintenance of a localized neutrophilic response at the inoculation site, and removal of neutrophils following vector transmission led to increased parasite-specific immune responses and promoted the efficacy of the killed vaccine. These observations identify the critical immunological factors influencing vaccine efficacy following natural transmission of Leishmania.

  6. Control and Simulation of Continuously Variable Transmission for Electric Transmission System

    Institute of Scientific and Technical Information of China (English)

    张豫南; 葛蕴珊; 马晓军; 臧克茂

    2004-01-01

    According to the study of electric transmission, the concept of the fore and the aft power chain is presented. The control method of continuously variable transmission is established in the aft chain of electric transmission based on brushless DC motor. A fuzzy controller is designed with continuous fuzzy variables and the simulation module of the aft power chain is proved by test. The fuzzy controller controls the process of continuously variable transmission steadily and the acceleration of vehicle is quick according to simulation results. The elementary performance exhibited in the simulation is a foundation for the further study of the electric transmission track vehicle.

  7. [Basic research on BSE transmission to people].

    Science.gov (United States)

    Bodemer, W; Kaup, F J

    2002-08-01

    Prion diseases of animal and man belong to neurological diseases with amyloidal deposition of the respective proteins. As to prion disease, the cellular prionprotein is in its abnormal isoform(s) an essential component of prionprotein aggregates found in affected tissue. In contrast to all neurodegenerative diseases like Morbus Alzheimer or Huntington's disease, prion diseases are transmissible. Therefore, prion diseases were designated Transmissible Spongiform Encephalopathies (TSE). The diseases are well known since decades. Scrapie was first described around 1750, a BSE case was reported in the 1850, most likely a misdiagnosis, and in 1920/1930 the human Creutzfeldt-Jakob disease (CJD) had been described. Transmission of CJD i.e. Kuru had been suspected in the early 1950s and erronously classified as slow virus disease. The CJD transmission posed a problem to humans when transplants from CJD cases were used for treatment. Fortunately, these iatrogenic transmissions remained limited. But with the advent of BSE and appearance of variant CJD cases in the UK and some places in Europe scientists suspected that transmission from cattle to man could have happened. From animal models we know of successful transmission via several routes. Species barriers do not completely prevent transmission. Rather transmission barriers might exist controlling individual susceptibility against prions. Modes of transmission, susceptibility for transmission, identification of receptor molecules as well as molecular mechanisms of the transmission process are intensely investigated. Current knowledge let us to assume that inapparent stages of prion infection pretend a (not existing) species barrier. This inapparent infection preceeds overt disease and, thus, most re-search focuses on the development of highly sensitive assay systems for detection of minute amounts of pathological prionprotein in suspected cases. Inapparence also should warn us to underestimate BSE or human vCJD cases; at

  8. Signal transmission in a Y-shaped one-way chain

    CERN Document Server

    Liang, Xiaoming; Lv, Huaping

    2013-01-01

    It has been found that noise plays a key role to improve signal transmission in a one-way chain of bistable systems [Zhang et al., Phys. Rev. E 58, 2952 (1998)]. We here show that the signal transmission can be sharply improved without the aid of noise, if the one-way chain with a single source node is changed with two source nodes becoming a Y-shaped one-way chain. We further reveal that the enhanced signal transmission in the Y-shaped one-way chain is regulated by coupling strength, and that it is robust to noise perturbation and input signal irregularity. We finally analyze the mechanism of the enhanced signal transmission by the Y-shaped structure.

  9. Super-transmission from a finite subwavelength arrangement of slits in a metal film.

    Science.gov (United States)

    Chen, Shuwen; Jin, Shilong; Gordon, Reuven

    2014-06-02

    A theory is presented for the transmission of transverse magnetic waves through a finite number of subwavelength slits in metal film. While a single slit achieves the single channel limit on resonance, multiple slits show super-transmission exceeding the single channel limit. The phenomenon of super-transmission is revealed as a result of cross-coupling of modes and confirmed by simulations. The influence of finite permittivity in the IR and microwave regime is included by perturbative corrections to the theory. The theory agrees quantitatively with past experiments and finite-difference time-domain simulations. By considering two or more modes in the slit region, our theory provides an approach to the analysis of cross-coupling among slits, which allows for super-transmission and features of a Fano resonance.

  10. Sexual transmission of human T-cell lymphotropic virus type 1

    Directory of Open Access Journals (Sweden)

    Arthur Paiva

    2014-06-01

    Full Text Available Human T-cell lymphotropic virus type 1 (HTLV-1 is endemic in many parts of the world and is primarily transmitted through sexual intercourse or from mother to child. Sexual transmission occurs more efficiently from men to women than women to men and might be enhanced by sexually transmitted diseases that cause ulcers and result in mucosal ruptures, such as syphilis, herpes simplex type 2 (HSV-2, and chancroid. Other sexually transmitted diseases might result in the recruitment of inflammatory cells and could increase the risk of HTLV-1 acquisition and transmission. Additionally, factors that are associated with higher transmission risks include the presence of antibodies against the viral oncoprotein Tax (anti-Tax, a higher proviral load in peripheral blood lymphocytes, and increased cervicovaginal or seminal secretions. Seminal fluid has been reported to increase HTLV replication and transmission, whereas male circumcision and neutralizing antibodies might have a protective effect. Recently, free virions were discovered in plasma, which reveals a possible new mode of HTLV replication. It is unclear how this discovery might affect the routes of HTLV transmission, particularly sexual transmission, because HTLV transmission rates are significantly higher from men to women than women to men.

  11. Combining contact tracing with targeted indoor residual spraying significantly reduces dengue transmission

    Science.gov (United States)

    Vazquez-Prokopec, Gonzalo M.; Montgomery, Brian L.; Horne, Peter; Clennon, Julie A.; Ritchie, Scott A.

    2017-01-01

    The widespread transmission of dengue viruses (DENV), coupled with the alarming increase of birth defects and neurological disorders associated with Zika virus, has put the world in dire need of more efficacious tools for Aedes aegypti–borne disease mitigation. We quantitatively investigated the epidemiological value of location-based contact tracing (identifying potential out-of-home exposure locations by phone interviews) to infer transmission foci where high-quality insecticide applications can be targeted. Space-time statistical modeling of data from a large epidemic affecting Cairns, Australia, in 2008–2009 revealed a complex pattern of transmission driven primarily by human mobility (Cairns accounted for ~60% of virus transmission to and from residents of satellite towns, and 57% of all potential exposure locations were nonresidential). Targeted indoor residual spraying with insecticides in potential exposure locations reduced the probability of future DENV transmission by 86 to 96%, compared to unsprayed premises. Our findings provide strong evidence for the effectiveness of combining contact tracing with residual spraying within a developed urban center, and should be directly applicable to areas with similar characteristics (for example, southern USA, Europe, or Caribbean countries) that need to control localized Aedes-borne virus transmission or to protect pregnant women’s homes in areas with active Zika transmission. Future theoretical and empirical research should focus on evaluation of the applicability and scalability of this approach to endemic areas with variable population size and force of DENV infection. PMID:28232955

  12. Extraordinary transmission of gigahertz surface acoustic waves.

    Science.gov (United States)

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H; Wright, Oliver B

    2016-09-19

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3-50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging.

  13. Extraordinary transmission of gigahertz surface acoustic waves

    Science.gov (United States)

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H.; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H.; Wright, Oliver B.

    2016-01-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3–50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging. PMID:27640998

  14. Extraordinary transmission of gigahertz surface acoustic waves

    Science.gov (United States)

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H.; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H.; Wright, Oliver B.

    2016-09-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3–50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging.

  15. Differential mechanisms of transmission and plasticity at mossy fiber synapses.

    Science.gov (United States)

    McBain, Chris J

    2008-01-01

    The last few decades have seen the hippocampal formation at front and center in the field of synaptic transmission. However, much of what we know about hippocampal short- and long-term plasticity has been obtained from research at one particular synapse; the Schaffer collateral input onto principal cells of the CA1 subfield. A number of recent studies, however, have demonstrated that there is much to be learned about target-specific mechanisms of synaptic transmission by study of the lesser known synapse made between the granule cells of the dentate gyrus; the so-called mossy fiber synapse, and its targets both within the hilar region and the CA3 hippocampus proper. Indeed investigation of this synapse has provided an embarrassment of riches concerning mechanisms of transmission associated with feedforward excitatory and inhibitory control of the CA3 hippocampus. Importantly, work from a number of labs has revealed that mossy fiber synapses possess unique properties at both the level of their anatomy and physiology, and serve as an outstanding example of a synapse designed for target-specific compartmentalization of synaptic transmission. The purpose of the present review is to highlight several aspects of this synapse as they pertain to a novel mechanism of bidirectional control of synaptic plasticity at mossy fiber synapses made onto hippocampal stratum lucidum interneurons. It is not my intention to pour over all that is known regarding the mossy fiber synapse since many have explored this topic exhaustively in the past and interested readers are directed to other fine reviews (Henze et al., 2000; Urban et al., 2001; Lawrence and McBain, 2003; Bischofberger et al., 2006; Nicoll and Schmitz, 2005).

  16. Transmission of sheep-bovine spongiform encephalopathy to pigs.

    Science.gov (United States)

    Hedman, Carlos; Bolea, Rosa; Marín, Belén; Cobrière, Fabien; Filali, Hicham; Vazquez, Francisco; Pitarch, José Luis; Vargas, Antonia; Acín, Cristina; Moreno, Bernardino; Pumarola, Martí; Andreoletti, Olivier; Badiola, Juan José

    2016-01-07

    Experimental transmission of the bovine spongiform encephalopathy (BSE) agent has been successfully reported in pigs inoculated via three simultaneous distinct routes (intracerebral, intraperitoneal and intravenous). Sheep derived BSE (Sh-BSE) is transmitted more efficiently than the original cattle-BSE isolate in a transgenic mouse model expressing porcine prion protein. However, the neuropathology and distribution of Sh-BSE in pigs as natural hosts, and susceptibility to this agent, is unknown. In the present study, seven pigs were intracerebrally inoculated with Sh-BSE prions. One pig was euthanized for analysis in the preclinical disease stage. The remaining six pigs developed neurological signs and histopathology revealed severe spongiform changes accompanied by astrogliosis and microgliosis throughout the central nervous system. Intracellular and neuropil-associated pathological prion protein (PrP(Sc)) deposition was consistently observed in different brain sections and corroborated by Western blot. PrP(Sc) was detected by immunohistochemistry and enzyme immunoassay in the following tissues in at least one animal: lymphoid tissues, peripheral nerves, gastrointestinal tract, skeletal muscle, adrenal gland and pancreas. PrP(Sc) deposition was revealed by immunohistochemistry alone in the retina, optic nerve and kidney. These results demonstrate the efficient transmission of Sh-BSE in pigs and show for the first time that in this species propagation of bovine PrP(Sc) in a wide range of peripheral tissues is possible. These results provide important insight into the distribution and detection of prions in non-ruminant animals.

  17. Research on stepless transmission utilizing noncircular gears

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmission ratio etc. are investigated in detail for each unit. Following this, several examples of using a noncircular gear pair in the units and their manipulation technique are introduced.

  18. Robust hyperchaotic synchronization via analog transmission line

    Science.gov (United States)

    Sadoudi, S.; Tanougast, C.

    2016-02-01

    In this paper, a novel experimental chaotic synchronization technique via analog transmission is discussed. We demonstrate through Field-Programmable Gate Array (FPGA) implementation design the robust synchronization of two embedded hyperchaotic Lorenz generators interconnected with an analog transmission line. The basic idea of this work consists in combining a numerical generation of chaos and transmitting it with an analog signal. The numerical chaos allows to overcome the callback parameter mismatch problem and the analog transmission offers robust data security. As application, this technique can be applied to all families of chaotic systems including time-delayed chaotic systems.

  19. Concurrent Wind Cooling in Power Transmission Lines

    Energy Technology Data Exchange (ETDEWEB)

    Jake P Gentle

    2012-08-01

    Idaho National Laboratory and the Idaho Power Company, with collaboration from Idaho State University, have been working on a project to monitor wind and other environmental data parameters along certain electrical transmission corridors. The combination of both real-time historical weather and environmental data is being used to model, validate, and recommend possibilities for dynamic operations of the transmission lines for power and energy carrying capacity. The planned results can also be used to influence decisions about proposed design criteria for or upgrades to certain sections of the transmission lines.

  20. Joint source-channel video transmission

    CERN Document Server

    Zhai, Fan

    2007-01-01

    This book deals with the problem of joint source-channel video transmission, i.e., the joint optimal allocation of resources at the application layer and the other network layers, such as data rate adaptation, channel coding, power adaptation in wireless networks, quality of service (QoS) support from the network, and packet scheduling, for efficient video transmission. Real-time video communication applications, such as videoconferencing, video telephony, and on-demand video streaming, have gained increased popularity. However, a key problem in video transmission over the existing Internet an

  1. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT II, MECHANICAL TRANSMISSIONS.

    Science.gov (United States)

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF MECHANICAL TRANSMISSIONS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) PURPOSE OF TRANSMISSIONS, (2) RATIO DIFFERENCE, (3) CONSTANT MESH TRANSMISSIONS, (4) FOUR-SPEED TRUCK TRANSMISSION POWER FLOW, AND (5) TRANSMISSION TROUBLESHOOTING.…

  2. New dual clutch transmission for tractors; Neues Doppelkupplungsgetriebe fuer Traktoren

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Joerg [John Deere Werke, Mannheim (Germany)

    2012-10-15

    John Deere presented its new 6R series of tractors at Agritechnica 2011. The tractors are available since the summer of this year, with a double clutch transmission, a completely new type of transmission for agricultural machinery. This transmission concept combines the advantages of mechanical manual transmissions (high efficiency) and stepless transmissions (convenient driving and operation). (orig.)

  3. Spatial patterns in discordant diagnostic test results for Chagas disease: links to transmission hotspots.

    Science.gov (United States)

    Levy, Michael Z; Bowman, Natalie M; Kawai, Vivian; Plotkin, Joshua B; Waller, Lance A; Cabrera, Lilia; Steurer, Frank; Seitz, Amy E; Pinedo-Cancino, Viviana V; Cornejo del Carpio, Juan Geny; Cordova Benzaquen, Eleazar; McKenzie, F Ellis; Maguire, James H; Gilman, Robert H; Bern, Caryn

    2009-04-15

    Diagnosis of Chagas disease is hindered by discordance between screening and confirmatory test results for Trypanosoma cruzi infection. In periurban Arequipa, Peru, spatial analysis revealed that individuals with discordant test results are spatially clustered in hotspots of T. cruzi transmission, suggesting that discordant results likely represent true infections in this setting.

  4. Current status and future directions for in situ transmission electron microscopy

    DEFF Research Database (Denmark)

    Taheri, Mitra L.; Stach, Eric A.; Arslan, Ilke

    2016-01-01

    This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of scientists, representing academia, government labs...

  5. Acquisition and transmission of potato leafroll virus by Myzus persicae; quantitative aspects.

    NARCIS (Netherlands)

    Heuvel, van den J.F.J.M.

    1991-01-01

    Studying the transmission of potato leafroll virus (PLRV) by Myzus persicae from infected Physalis floridana plants, revealed that the ability of aphids to transmit the virus differed widely among individuals and strongly depended on the biotype of the vector aphid and the age of the virus source. V

  6. Time-of-Flight Effects in Microwave Transmission Through a Thin Metal Slab

    DEFF Research Database (Denmark)

    Henningsen, J. O.; Falk, David S.

    1971-01-01

    A 45-GHz size-effect experiment on Ag revealed significant structure in the combined transmission and leakage signal below the first-belly-electron size effects. The oscillations, which behave differently for different field orientations, are shown to be due to the time-of-flight phase delay of e...

  7. SPINEL METAL INTERFACES IN LASER COATED STEELS - A TRANSMISSION ELECTRON-MICROSCOPY STUDY

    NARCIS (Netherlands)

    ZHOU, XB; DEHOSSON, JTM

    1991-01-01

    This paper reports on coating a Duplex steel SAF 2205 and stainless steel 304 by bringing a mixture of Cr2O3 and Fe powder into a laser beam. Transmission electron microscopy reveals that in the case of proper bonding between substrate and coating a spinel structure around the composition FeCr2O4 co

  8. Spinel/Metal Interfaces in Laser Coated Steels : A Transmission Electron Microscopy Study

    NARCIS (Netherlands)

    Zhou, X.B.; Hosson, J.Th.M. De

    1991-01-01

    This paper reports on coating a Duplex steel SAF 2205 and stainless steel 304 by bringing a mixture of Cr2O3 and Fe powder into a laser beam. Transmission electron microscopy reveals that in the case of proper bonding between substrate and coating a spinel structure around the composition FeCr2O4 co

  9. Risk factors of influenza transmission in households

    OpenAIRE

    Viboud, Cécile; Boëlle, Pierre-Yves; Cauchemez, Simon; Lavenu, Audrey; Valleron, Alain-Jacques; Flahault, Antoine; Carrat, Fabrice

    2004-01-01

    Background: Influenza transmission in households is a subject of renewed interest, as the vaccination of children is currently under debate and antiviral treatments have been approved for prophylactic use.

  10. Ultrahigh-Speed Optical Transmission Technology

    CERN Document Server

    Weber, Hans-Georg

    2007-01-01

    Ultrahigh-speed optical transmission technology is a key technology for increasing the communication capacity. In optical fibre networks, the number of wavelength channels and the bit rate per wavelength channel, i.e. the TDM (Time Division Multiplexing) bit rate, determine the transmission capacity. Currently, TDM bit rates of more than 40 Gbit/s require optical signal processing (Optical Time Division Multiplexing, OTDM). OTDM bit rates of up to 1.2 Tbit/s have already been reported. The devices developed for ultrahigh-speed optical transmission are not limited to communication applications only. They are key devices for high-speed optical signal processing, i.e. monitoring, measurement and control, and will thus give a wide technological basis for innovative science and technology. All these aspects of ultrahigh-speed optical transmission technology are described in detail in this book.

  11. Transmission and Institutional Infection Control of Tuberculosis.

    Science.gov (United States)

    Nardell, Edward A

    2016-02-01

    Tuberculosis (TB) transmission control in institutions is evolving with increased awareness of the rapid impact of treatment on transmission, the importance of the unsuspected, untreated case of transmission, and the advent of rapid molecular diagnostics. With active case finding based on cough surveillance and rapid drug susceptibility testing, in theory, it is possible to be reasonably sure that no patient enters a facility with undiagnosed TB or drug resistance. Droplet nuclei transmission of TB is reviewed with an emphasis on risk factors relevant to control. Among environmental controls, natural ventilation and upper-room ultraviolet germicidal ultraviolet air disinfection are the most cost-effective choices, although high-volume mechanical ventilation can also be used. Room air cleaners are generally not recommended. Maintenance is required for all engineering solutions. Finally, personal protection with fit-tested respirators is used in many situations where administrative and engineering methods cannot assure protection.

  12. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    Denmark is taking on the exciting project of undergrounding the electricity transmission grid. In 2009 it was decided by the Danish government to underground large parts of the 400 kV and the entire 132-150 kV transmission network before the end of 2030. For ensuring network stability...... and economical gain, such severe network changes necessitate correct estimation and optimisation of load conditions in the cable grid. Both IEC and IEEE have published standards for rating transmission cables' current carrying capacity. These standards are based on assumptions of a number of parameters...... of better calculation of the AC resistance of transmission cable conductors, in particular regarding higher frequencies. In this way, also losses under harmonics can be covered. Furthermore, the model is suitable for modelling of transient attenuation in high voltage cables. The AC resistance is calculated...

  13. Wireless power transmission - Applications and technology status

    Science.gov (United States)

    Schupp, Bradford W.; Brown, Alan M.

    The history of wireless power transmission systems is reviewed and current and future applications and technology are discussed. Design constraints for terrestrial systems, airborne platforms, and space systems are presented.

  14. Advanced Rotorcraft Transmission (ART) program review

    Science.gov (United States)

    Kish, Jules

    1990-01-01

    This paper summarizes the work accomplished to date on the NASA/Army Advanced Rotorcraft Transmission (ART) program. A 23-percent weight reduction has been demonstrated for a high output reduction ratio split path transmission compared to an aggressive program goal of 25-percent. Greater than 10 dB noise reduction in the cabin is achieved by the use of high contact ratio spur and double helical gears. In addition, mean times between transmission removals have been increased by almost four fold. These performance gains have been achieved by application of advanced transmission technology concepts. Technology areas are being explored which offer high gain but at relatively high risk in such areas as composites, split power gear concepts, double helical gears, new gear materials, high speed spring clutches, and ceramic rolling element bearings.

  15. Modelling of vibration of gear transmissions

    Science.gov (United States)

    Zeman, Vladimir; Nemecek, Josef

    The method for mathematical modeling of spatial vibrations of the spur gear transmissions is presented. This method enables a substantial reduction of the number of degrees of freedom with relatively high accuracy in calculating vibration amplitude.

  16. Transmission of torque at the nanoscale

    Science.gov (United States)

    Williams, Ian; Oğuz, Erdal C.; Speck, Thomas; Bartlett, Paul; Löwen, Hartmut; Royall, C. Patrick

    2016-01-01

    In macroscopic mechanical devices, torque is transmitted through gearwheels and clutches. In the construction of devices at the nanoscale, torque and its transmission through soft materials will be a key component. However, this regime is dominated by thermal fluctuations leading to dissipation. Here we demonstrate the principle of torque transmission for a disc-like colloidal assembly exhibiting clutch-like behaviour, driven by 27 particles in optical traps. These are translated on a circular path to form a rotating boundary that transmits torque to additional particles confined to the interior. We investigate this transmission and find that it is determined by solid-like or fluid-like behaviour of the device and a stick-slip mechanism reminiscent of macroscopic gearwheels slipping. The transmission behaviour is predominantly governed by the rotation rate of the boundary and the density of the confined system. We determine the efficiency of our device and thus optimize conditions to maximize power output.

  17. Hybrid Transmission Scheme for MIMO Relay Channels

    Directory of Open Access Journals (Sweden)

    Guangming Xu

    2009-11-01

    Full Text Available To improve the achievable rate for the MIMO channels, we propose a hybrid transmission (HT scheme that mixes half-duplex decode-and-forward cooperative relaying transmission (DFRH)with direct transmission (DT. In the HT scheme, the source message is divided into two parts: one is transmitted by DFRH scheme and another is transmitted by DT scheme. Precoding and decoding are considered to convert the original MIMO relay channel into several parallel subchannels so that resource allocation can be easily performed. We focus on the spatial subchannel and power allocation problem. The objective of this problem is to maximize the total achievable rate under the constraints of joint total transmission power. Simulation results show that significant capacity gain can be achieved by the HT scheme compared to the DT scheme and the pure DFRH scheme.

  18. Lack of transplacental transmission of Bartonella bovis.

    Science.gov (United States)

    Chastant-Maillard, S; Boulouis, H-J; Reynaud, K; Thoumire, S; Gandoin, C; Bouillin, C; Cordonnier, N; Maillard, R

    2015-02-01

    Transplacental transmission of Bartonella spp. has been reported for rodents, but not for cats and has never been investigated in cattle. The objective of this study was to assess vertical transmission of Bartonella in cattle. Fifty-six cow-calf pairs were tested before (cows) and after (calves) caesarean section for Bartonella bacteremia and/or serology, and the cotyledons were checked for gross lesions and presence of the bacteria. None of the 29 (52%) bacteremic cows gave birth to bacteremic calves, and all calves were seronegative at birth. Neither placentitis nor vasculitis were observed in all collected cotyledons. Bartonella bovis was not detected in placental cotyledons. Therefore, transplacental transmission of B. bovis and multiplication of the bacteria in the placenta do not seem likely. The lack of transplacental transmission may be associated with the particular structure of the placenta in ruminants or to a poor affinity/agressiveness of B. bovis for this tissue.

  19. Television signal transmission characteristics via BSE

    Science.gov (United States)

    Kozu, T.; Yamamoto, M.; Ohuchi, C.; Sugimoto, Y.; Fukuchi, H.

    1986-01-01

    The FM-TV signal transmission characteristics via BSE measured at the Main Transit and Receiving Station are described. Measurements are reported using 'standard parameters' which were carried out every half year from 1978 to 1980, measuring the video signal to noise ratio, waveform distortion, DG-DP, amplitude-frequency characteristics of video and audio signal, and the subjective assessment of video signal quality. These characteristics were good enough to broadcast a high-quality TV signal, and no degradation was observed for two years. Measurements using 'nonstandard parameters' were performed in order to study transmission parameters suitable for satellite broadcasting. Results are reported for one sound channel transmission using one FM subcarrier and for two sound channel transmission using two FM subcarriers.

  20. 4th International Conference on Power Transmissions

    CERN Document Server

    2013-01-01

    This books contains the Proceedings of the 4th International Conference on Power Transmissions, that was held in Sinaia, Romania from June 20 -23, 2012. Power Transmissions is a very complex and multi-disciplinary scientific field of Mechanical Engineering that covers the different types of transmissions (mechanical, hydraulic, pneumatic) as well as all the machine elements involved, such as gears, bearings, shafts, couplings and a lot more. It concerns not only their basic theory but also their design, analysis, testing, application and maintenance. The requirements set to modern power transmissions are really tough to meet: They need to be more efficient, stronger, smaller, noiseless, easier to produce and to cost less. There is a strong demand to become easier in operation and maintenance, or even automatic and in maintenance-free. Last but not least, they should be easily recycled and respect the environment. Joint efforts of specialists from both academia and industry can significantly contribute to fulf...

  1. High Voltage Power Transmission for Wind Energy

    Science.gov (United States)

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  2. VT Electric Transmission Line Corridors - substation points

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The ELTRN layer depicts electric transmission line corridors in Vermont. Various methods have been used to digitize features. The data layer...

  3. VT Electric Transmission Line Corridors - corridor lines

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The ELTRN layer depicts electric transmission line corridors in Vermont. Various methods have been used to digitize features. The data layer...

  4. Composite Based EHV AC Overhead Transmission Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard

    Overhead lines at transmission level are the backbone of any national power grid today. New overhead line projects however are at the same time subject to ever greater public resistance due to the lines environmental impact. As full undergrounding of transmission lines at extra high voltage (EHV......) levels are still not seen as possibility, the future expansion of transmission grids are dependent on new solutions with lessened environment impact, especially with regard to the visual impact. In the present Thesis, composite materials and composite based overhead line components are presented...... and analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...

  5. The transmissible spongiform encephalopathies of livestock

    Science.gov (United States)

    Prion diseases or transmissible spongiform encephalopathies (TSEs) are fatal protein misfolding neurodegenerative diseases. TSEs have been described in several species including bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep and goats, chronic wasting disease (CWD) in cervids, tr...

  6. Permit Review - Florida Gas Transmission Company (FGT)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Branch of Air Quality Permit Review for Florida Gas Transmission Company and their expansion of Compressor Station Number 10 in Wiggins, Mississippi. The facility is...

  7. Spectrally efficient polymer optical fiber transmission

    Science.gov (United States)

    Randel, Sebastian; Bunge, Christian-Alexander

    2011-01-01

    The step-index polymer optical fiber (SI-POF) is an attractive transmission medium for high speed communication links in automotive infotainment networks, in industrial automation, and in home networks. Growing demands for quality of service, e.g., for IPTV distribution in homes and for Ethernet based industrial control networks will necessitate Gigabit speeds in the near future. We present an overview on recent advances in the design of spectrally efficient and robust Gigabit-over-SI-POF transmission systems.

  8. Transmission Line Resonator Segmented with Series Capacitors

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Boer, Vincent; Petersen, Esben Thade

    2016-01-01

    Transmission line resonators are often used as coils in high field MRI. Due to distributed nature of such resonators, coils based on them produce inhomogeneous field. This work investigates application of series capacitors to improve field homogeneity along the resonator. The equations for optimal...... values of evenly distributed capacitors are presented. The performances of the segmented resonator and a regular transmission line resonator are compared....

  9. Human to Human Transmission of Brucella Melitensis

    Directory of Open Access Journals (Sweden)

    Patrice Vigeant

    1995-01-01

    Full Text Available Human brucellosis is acquired mainly through contact with infected animal tissues, ingestion of unpasteurized dairy products or infected aerosols. Person to person transmission is still considered uncertain. The case of a woman diagnosed with proven brucellosis after her husband suffered a relapse of bacteremia with Brucella melitensis biotype 3, which was originally acquired abroad by eating goat cheese, is described. It was postulated that person to person spread of brucellosis is a likely mode of transmission in this case.

  10. Maritime wideband communication networks video transmission scheduling

    CERN Document Server

    Yang, Tingting

    2014-01-01

    This Springer Brief covers emerging maritime wideband communication networks and how they facilitate applications such as maritime distress, urgency, safety and general communications. It provides valuable insight on the data transmission scheduling and protocol design for the maritime wideband network. This brief begins with an introduction to maritime wideband communication networks including the architecture, framework, operations and a comprehensive survey on current developments. The second part of the brief presents the resource allocation and scheduling for video packet transmission wit

  11. Lateral force transmission between human tendon fascicles

    DEFF Research Database (Denmark)

    Haraldsson, Bjarki T; Aagaard, Per; Qvortrup, Klaus

    2008-01-01

    Whether adjacent collagen fascicles transmit force in parallel is unknown. The purpose of the present study was to examine the magnitude of lateral force transmission between adjacent collagen fascicles from the human patellar and Achilles tendon. From each sample two adjacent strands of fascicles...... adjacent collagen fascicles in human tendons is small or negligible, suggesting that tendon fascicles largely act as independent structures and that force transmission principally takes place within the individual fascicles....

  12. Donor Transmission of Melanoma Following Renal Transplant

    Directory of Open Access Journals (Sweden)

    Kathryn T. Chen

    2012-01-01

    Full Text Available Donor transmission of melanoma is one of the more common and lethal of recipient malignancies, often presenting with systemic disease. Although some patients may receive durable remission of melanoma following explantation of the allograft and withdrawal of immunosuppression, donor transmission of melanoma is fatal in most patients. Here we present a case of a 44-year-old male who developed metastatic melanoma following renal transplant.

  13. Donor transmission of melanoma following renal transplant.

    Science.gov (United States)

    Chen, Kathryn T; Olszanski, Anthony; Farma, Jeffrey M

    2012-01-01

    Donor transmission of melanoma is one of the more common and lethal of recipient malignancies, often presenting with systemic disease. Although some patients may receive durable remission of melanoma following explantation of the allograft and withdrawal of immunosuppression, donor transmission of melanoma is fatal in most patients. Here we present a case of a 44-year-old male who developed metastatic melanoma following renal transplant.

  14. Elephant-to-Human Transmission of Tuberculosis

    Centers for Disease Control (CDC) Podcasts

    2011-02-23

    This podcast reports on the transmission of TB from elephants to humans. Dr. Rendi Murphree, Epidemic Intelligence Service Officer at the Centers for Disease Control and Prevention and Vanderbilt University Visiting Scholar, discusses the recent elephant-to-human transmission of tuberculosis at an elephant refuge in Tennessee.  Created: 2/23/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/23/2011.

  15. Testing Selective Transmission with Low Power Listening

    DEFF Research Database (Denmark)

    Hansen, Morten Tranberg; Arroyo-Valles, Rocio; Cid-Sueiro, Jesus

    2010-01-01

    Selective transmission policies allow nodes in a sensor network to autonomously decide between transmitting or discarding packets depending on the importance of the information content and the energetic cost of communications. The potential benefits of these policies depend on the capability...... of nodes to estimate its current energy consumption patterns. As a case study, this paper tests the performance of a particular selective transmission algorithm over a simple network using a low power listening MAC protocol on real sensor node hardware....

  16. Reflection and transmission of conformal perturbation defects

    CERN Document Server

    Brunner, Ilka

    2015-01-01

    We consider reflection and transmission of interfaces which implement renormalisation group flows between conformal fixed points in two dimensions. Such an RG interface is constructed from the identity defect in the ultraviolet CFT by perturbing the theory on one side of the defect line. We compute reflection and transmission coefficients in perturbation theory to third order in the coupling constant and check our calculations against exact constructions of RG interfaces between coset models.

  17. ATTENUATION AND FLANKING TRANSMISSION IN LIGHTWEIGHT STRUCTURES

    DEFF Research Database (Denmark)

    Brunskog, Jonas; Lhomond, Alice; Ohlrich, Mogens

    2007-01-01

    In this paper the attenuation and flanking transmissions of impact noise in lightweight building structures is studied using a modal approach. The structural field is mainly analysed, putting the main attention to the parts being important in the modelling. The amount of attenuation produced...... by the periodically reinforcing beams used in lightweight building structures is analysed. The consequence of these factors in modelling flanking transmission is also discussed....

  18. ASYMPTOTIC SOLUTION TO MODEL FOR A CLASS OF VIRUS TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, a class of HIV virus transmission is considered. The transmissive dynamic model for the HIV virus is described. Using the functional-variational iteration theory, the rule for human group in the epidemic transmissive area is studied.

  19. Low voltage transmission electron microscopy of graphene.

    Science.gov (United States)

    Bachmatiuk, Alicja; Zhao, Jiong; Gorantla, Sandeep Madhukar; Martinez, Ignacio Guillermo Gonzalez; Wiedermann, Jerzy; Lee, Changgu; Eckert, Juergen; Rummeli, Mark Hermann

    2015-02-04

    The initial isolation of graphene in 2004 spawned massive interest in this two-dimensional pure sp(2) carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State-of-the-art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in-situ investigations is also presented.

  20. Wireless Power Transmission Using Resonance Inductive Coupling

    Directory of Open Access Journals (Sweden)

    Prof. Vishal V. Pande,

    2014-04-01

    Full Text Available In this paper, we present the concept of transmitting power without using wires i.e.transmitting power as Magnetic waves from one place to another is in order to reduce the transmission and distribution losses. This concept is known as Resonance Inductive Coupling (RIC. We also discussed the technological developments in Wireless Power Transmission (WPT. The advantages, disadvantages, biological impacts and applications of WPT are also presented. Wireless power or wireless energy transmission is the transmission of electrical energy from a power source to an electrical load without man-made conductors. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous, or impossible. the proportion of energy received becomes critical only if it is too low for the signal to be distinguished from the background noise. With wireless power, efficiency is the more significant parameter. A large part of the energy sent out by the generating plant must arrive at the receiver or receivers to make the system economical.The most common form of wireless power transmission is carried out using direct induction followed by resonant magnetic induction. Other methods under consideration are electromagnetic radiation in the form of microwaves or lasers and electrical conduction through natural media

  1. Determinants of Arbovirus Vertical Transmission in Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Sebastian Lequime

    2016-05-01

    Full Text Available Vertical transmission (VT and horizontal transmission (HT of pathogens refer to parental and non-parental chains of host-to-host transmission. Combining HT with VT enlarges considerably the range of ecological conditions in which a pathogen can persist, but the factors governing the relative frequency of each transmission mode are poorly understood for pathogens with mixed-mode transmission. Elucidating these factors is particularly important for understanding the epidemiology of arthropod-borne viruses (arboviruses of public health significance. Arboviruses are primarily maintained by HT between arthropod vectors and vertebrate hosts in nature, but are occasionally transmitted vertically in the vector population from an infected female to her offspring, which is a proposed maintenance mechanism during adverse conditions for HT. Here, we review over a century of published primary literature on natural and experimental VT, which we previously assembled into large databases, to identify biological factors associated with the efficiency of arbovirus VT in mosquito vectors. Using a robust statistical framework, we highlight a suite of environmental, taxonomic, and physiological predictors of arbovirus VT. These novel insights contribute to refine our understanding of strategies employed by arboviruses to persist in the environment and cause substantial public health concern. They also provide hypotheses on the biological processes underlying the relative VT frequency for pathogens with mixed-mode transmission that can be tested empirically.

  2. Determinants of Arbovirus Vertical Transmission in Mosquitoes.

    Science.gov (United States)

    Lequime, Sebastian; Paul, Richard E; Lambrechts, Louis

    2016-05-01

    Vertical transmission (VT) and horizontal transmission (HT) of pathogens refer to parental and non-parental chains of host-to-host transmission. Combining HT with VT enlarges considerably the range of ecological conditions in which a pathogen can persist, but the factors governing the relative frequency of each transmission mode are poorly understood for pathogens with mixed-mode transmission. Elucidating these factors is particularly important for understanding the epidemiology of arthropod-borne viruses (arboviruses) of public health significance. Arboviruses are primarily maintained by HT between arthropod vectors and vertebrate hosts in nature, but are occasionally transmitted vertically in the vector population from an infected female to her offspring, which is a proposed maintenance mechanism during adverse conditions for HT. Here, we review over a century of published primary literature on natural and experimental VT, which we previously assembled into large databases, to identify biological factors associated with the efficiency of arbovirus VT in mosquito vectors. Using a robust statistical framework, we highlight a suite of environmental, taxonomic, and physiological predictors of arbovirus VT. These novel insights contribute to refine our understanding of strategies employed by arboviruses to persist in the environment and cause substantial public health concern. They also provide hypotheses on the biological processes underlying the relative VT frequency for pathogens with mixed-mode transmission that can be tested empirically.

  3. Transmission models of tuberculosis in heterogeneous population

    Institute of Scientific and Technical Information of China (English)

    JIA Zhong-wei; LI Xiao-wen; FENG Dan; CAO Wu-chun

    2007-01-01

    Objective To review the transmission models of tuberculosis in heterogeneous population.Data sources The data used in this review were adopted mainly from the studies of models of tuberculosis reported from 1995 to 2006.Study selection Relevant literature on transmission models of tuberculosis in heterogeneous populations are referenced.Results Casual/random factors and genetic factors are the main reasons for epidemics of tuberculosis in recent years.Mass public transport is playing the primary role in casually close contact which can facilitate the transmission of tuberculosis. Genetic susceptibility not only varies endemic prevalence levels, but also drastically alters the effects of treatment for tuberculosis patients. Detailed studies further exhibit that casual contact and genetic factor are responsible for over 30%-40% of the total new cases in recent years. The prevalence of tuberculosis could double (from 33% to 60%)if a genetically susceptible phenotype is present in only 30% of the population. And some challenges have emerged along with these exciting results.Conclusions Casual/random contact, public transport and genetic susceptibility are responsible for most new tuberculosis cases and a wide variation in endemic tuberculosis levels between regions. Hence, the transmission model of tuberculosis in a heterogeneous population can provide more clues to underlying mechanism of tuberculosis transmission than in a homogeneous population. However, many challenges remain for us in understanding transmission of disease.

  4. A simple stochastic model with environmental transmission explains multi-year periodicity in outbreaks of avian flu.

    Directory of Open Access Journals (Sweden)

    Rong-Hua Wang

    Full Text Available Avian influenza virus reveals persistent and recurrent outbreaks in North American wild waterfowl, and exhibits major outbreaks at 2-8 years intervals in duck populations. The standard susceptible-infected- recovered (SIR framework, which includes seasonal migration and reproduction, but lacks environmental transmission, is unable to reproduce the multi-periodic patterns of avian influenza epidemics. In this paper, we argue that a fully stochastic theory based on environmental transmission provides a simple, plausible explanation for the phenomenon of multi-year periodic outbreaks of avian flu. Our theory predicts complex fluctuations with a dominant period of 2 to 8 years which essentially depends on the intensity of environmental transmission. A wavelet analysis of the observed data supports this prediction. Furthermore, using master equations and van Kampen system-size expansion techniques, we provide an analytical expression for the spectrum of stochastic fluctuations, revealing how the outbreak period varies with the environmental transmission.

  5. VLT FORS2 comparative transmission spectral survey of clear and cloudy exoplanet atmospheres

    Science.gov (United States)

    Nikolov, Nikolay; Sing, David K.; Gibson, Neale; Fortney, Jonathan J.; Evans, Tom M.; Barstow, Joanna; Kataria, Tiffany; Wilson, Paul

    2017-01-01

    Thousands of transiting exoplanets are known today but not many have been studied in transmission. While observations with the Hubble Space Telescope (HST) have started to reveal a diversity of atmosphere types, drawing robust conclusions about the underlying population is hampered by the small sample size. This can be greatly aided by ground-based telescopes, equipped with multi-object spectrographs by their unprecedented access to the abundance of fainter systems that HST cannot observe. We have initiated a ground-based, multi-object transmission spectroscopy of a handful of hot gas-giants, covering the wavelength range 360-850nm, using the recently upgraded FOcal Reducer and Spectrograph (FORS2) mounted on the Very Large Telescope (VLT). These exoplanets were selected for a comparative follow-up as their transmission spectra showed evidence for alkali metal absorption, based on the results of HST observations. Here we will discuss first results from the program, demonstrating an excellent agreement between the transmission spectra measured from VLT and HST and detections of Na and K absorption and scattering by clouds/hazes in the atmospheres of several exoplanets. More details will be discussed on the narrow alkali features obtained with FORS2 at higher resolution, revealing its high potential in obtaining optical transmission spectra, which can greatly aid comparative exoplanet studies.

  6. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    Energy Technology Data Exchange (ETDEWEB)

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  7. 320 Gb/s Single polarization OTDM Transmission over 80 km Standard Transmission Fiber

    DEFF Research Database (Denmark)

    Siahlo, Andrei; Seoane, Jorge; Clausen, Anders;

    2005-01-01

    Optical time-division multiplexing (OTDM) is an attractive technique for increasing the capacity of optical transmission systems. 320 Gbit/s single-channel and single-polarization error-free transmission over continuous spans of either 80 km SMF or 77 km NZDSF are realized.......Optical time-division multiplexing (OTDM) is an attractive technique for increasing the capacity of optical transmission systems. 320 Gbit/s single-channel and single-polarization error-free transmission over continuous spans of either 80 km SMF or 77 km NZDSF are realized....

  8. Gene expression analysis reveals early changes in several molecular pathways in cerebral malaria-susceptible mice versus cerebral malaria-resistant mice

    Directory of Open Access Journals (Sweden)

    Grau Georges E

    2007-12-01

    Full Text Available Abstract Background Microarray analyses allow the identification and assessment of molecular signatures in whole tissues undergoing pathological processes. To better understand cerebral malaria pathogenesis, we investigated intra-cerebral gene-expression profiles in well-defined genetically cerebral malaria-resistant (CM-R and CM-susceptible (CM-S mice, upon infection by Plasmodium berghei ANKA (PbA. We investigated mouse transcriptional responses at early and late stages of infection by use of cDNA microarrays. Results Through a rigorous statistical approach with multiple testing corrections, we showed that PbA significantly altered brain gene expression in CM-R (BALB/c, and in CM-S (CBA/J and C57BL/6 mice, and that 327 genes discriminated between early and late infection stages, between mouse strains, and between CM-R and CM-S mice. We further identified 104, 56, 84 genes with significant differential expression between CM-R and CM-S mice on days 2, 5, and 7 respectively. The analysis of their functional annotation indicates that genes involved in metabolic energy pathways, the inflammatory response, and the neuroprotection/neurotoxicity balance play a major role in cerebral malaria pathogenesis. In addition, our data suggest that cerebral malaria and Alzheimer's disease may share some common mechanisms of pathogenesis, as illustrated by the accumulation of β-amyloid proteins in brains of CM-S mice, but not of CM-R mice. Conclusion Our microarray analysis highlighted marked changes in several molecular pathways in CM-S compared to CM-R mice, particularly at early stages of infection. This study revealed some promising areas for exploration that may both provide new insight into the knowledge of CM pathogenesis and the development of novel therapeutic strategies.

  9. Functional analysis of the leading malaria vaccine candidate AMA-1 reveals an essential role for the cytoplasmic domain in the invasion process.

    Directory of Open Access Journals (Sweden)

    Moritz Treeck

    2009-03-01

    Full Text Available A key process in the lifecycle of the malaria parasite Plasmodium falciparum is the fast invasion of human erythrocytes. Entry into the host cell requires the apical membrane antigen 1 (AMA-1, a type I transmembrane protein located in the micronemes of the merozoite. Although AMA-1 is evolving into the leading blood-stage malaria vaccine candidate, its precise role in invasion is still unclear. We investigate AMA-1 function using live video microscopy in the absence and presence of an AMA-1 inhibitory peptide. This data reveals a crucial function of AMA-1 during the primary contact period upstream of the entry process at around the time of moving junction formation. We generate a Plasmodium falciparum cell line that expresses a functional GFP-tagged AMA-1. This allows the visualization of the dynamics of AMA-1 in live parasites. We functionally validate the ectopically expressed AMA-1 by establishing a complementation assay based on strain-specific inhibition. This method provides the basis for the functional analysis of essential genes that are refractory to any genetic manipulation. Using the complementation assay, we show that the cytoplasmic domain of AMA-1 is not required for correct trafficking and surface translocation but is essential for AMA-1 function. Although this function can be mimicked by the highly conserved cytoplasmic domains of P. vivax and P. berghei, the exchange with the heterologous domain of the microneme protein EBA-175 or the rhoptry protein Rh2b leads to a loss of function. We identify several residues in the cytoplasmic tail that are essential for AMA-1 function. We validate this data using additional transgenic parasite lines expressing AMA-1 mutants with TY1 epitopes. We show that the cytoplasmic domain of AMA-1 is phosphorylated. Mutational analysis suggests an important role for the phosphorylation in the invasion process, which might translate into novel therapeutic strategies.

  10. Propagation of epileptiform activity can be independent of synaptic transmission, gap junctions, or diffusion and is consistent with electrical field transmission.

    Science.gov (United States)

    Zhang, Mingming; Ladas, Thomas P; Qiu, Chen; Shivacharan, Rajat S; Gonzalez-Reyes, Luis E; Durand, Dominique M

    2014-01-22

    The propagation of activity in neural tissue is generally associated with synaptic transmission, but epileptiform activity in the hippocampus can propagate with or without synaptic transmission at a speed of ∼0.1 m/s. This suggests an underlying common nonsynaptic mechanism for propagation. To study this mechanism, we developed a novel unfolded hippocampus preparation, from CD1 mice of either sex, which preserves the transverse and longitudinal connections and recorded activity with a penetrating microelectrode array. Experiments using synaptic transmission and gap junction blockers indicated that longitudinal propagation is independent of chemical or electrical synaptic transmission. Propagation speeds of 0.1 m/s are not compatible with ionic diffusion or pure axonal conduction. The only other means of communication between neurons is through electric fields. Computer simulations revealed that activity can indeed propagate from cell to cell solely through field effects. These results point to an unexpected propagation mechanism for neural activity in the hippocampus involving endogenous field effect transmission.

  11. BDNF-mediated modulation of glycine transmission on rat spinal motoneurons.

    Science.gov (United States)

    Ding, Jian-Dong; Tang, Xian-Ye; Shi, Jian-Gang; Jia, Lian-Shun

    2014-08-22

    BDNF has a widespread distribution in the central and peripheral nervous systems, suggesting that BDNF may play a role in the regulation of motor control. However, the direct actions of BDNF on the motoneurons and their underlying mechanisms are still largely unknown to date. Therefore, by using whole-cell patch clamp recordings, quantitative RT-PCR and immunocytochemistry, the present study was designed to investigate the effects of BDNF on electrical activity and glycinergic transmission on the motoneurons and the underlying receptor mechanism. The results reveal: (i) BDNF did not produce a direct excitatory or inhibitory effect on the motoneurons; (ii) BDNF dose-dependently increased the glycinergic transmission on the motoneurons; (iii) glycinergic transmission on motoneurons was a direct postsynaptic effect; (iv) BDNF-induced enhancement of the glycinergic transmission was mediated by the activation of TrkB receptors; and (v) BDNF and its receptors TrkB had an extensive expression in the motoneurons. These results suggest that BDNF is directly involved in the regulation of glycinergic transmission on the motoneurons through postsynaptic TrkB receptors. Considering that the glycinergic synaptic transmission of motoneurons mainly comes from Renshaw cells, the important inhibitory interneurons of spinal cord, we speculate that BDNF may play an important role in the information integration in the spinal cord and participate in the sensitivity of motoneurons.

  12. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus

    Science.gov (United States)

    Tully, Damien C.; Ogilvie, Colin B.; Batorsky, Rebecca E.; Bean, David J.; Power, Karen A.; Ghebremichael, Musie; Bedard, Hunter E.; Gladden, Adrianne D.; Seese, Aaron M.; Amero, Molly A.; Lane, Kimberly; McGrath, Graham; Bazner, Suzane B.; Tinsley, Jake; Lennon, Niall J.; Henn, Matthew R.; Brumme, Zabrina L.; Norris, Philip J.; Rosenberg, Eric S.; Mayer, Kenneth H.; Jessen, Heiko; Kosakovsky Pond, Sergei L.; Walker, Bruce D.; Altfeld, Marcus; Carlson, Jonathan M.; Allen, Todd M.

    2016-01-01

    Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM) exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX) transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU), we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic “signatures” within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission. PMID:27163788

  13. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus.

    Directory of Open Access Journals (Sweden)

    Damien C Tully

    2016-05-01

    Full Text Available Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU, we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.

  14. Light Focusing and Two-Dimensional Imaging Through Scattering Media using the Photoacoustic Transmission-Matrix with an Ultrasound Array

    CERN Document Server

    Chaigne, Thomas; Katz, Ori; Bossy, Emmanuel; Gigan, Sylvain

    2014-01-01

    We implement the photoacoustic transmission-matrix approach on a two-dimensional photoacoustic imaging system, using a 15 MHz linear ultrasound array. Using a black leaf skeleton as a complex absorbing structure, we demonstrate that the photoacoustic transmission-matrix approach allows to reveal structural features that are invisible in conventional photoacoustic images, as well as to selectively control light focusing on absorbing targets, leading to a local enhancement of the photoacoustic signal.

  15. Pneumothorax effects on pulmonary acoustic transmission.

    Science.gov (United States)

    Mansy, Hansen A; Balk, Robert A; Warren, William H; Royston, Thomas J; Dai, Zoujun; Peng, Ying; Sandler, Richard H

    2015-08-01

    Pneumothorax (PTX) is an abnormal accumulation of air between the lung and the chest wall. It is a relatively common and potentially life-threatening condition encountered in patients who are critically ill or have experienced trauma. Auscultatory signs of PTX include decreased breath sounds during the physical examination. The objective of this exploratory study was to investigate the changes in sound transmission in the thorax due to PTX in humans. Nineteen human subjects who underwent video-assisted thoracic surgery, during which lung collapse is a normal part of the surgery, participated in the study. After subjects were intubated and mechanically ventilated, sounds were introduced into their airways via an endotracheal tube. Sounds were then measured over the chest surface before and after lung collapse. PTX caused small changes in acoustic transmission for frequencies below 400 Hz. A larger decrease in sound transmission was observed from 400 to 600 Hz, possibly due to the stronger acoustic transmission blocking of the pleural air. At frequencies above 1 kHz, the sound waves became weaker and so did their changes with PTX. The study elucidated some of the possible mechanisms of sound propagation changes with PTX. Sound transmission measurement was able to distinguish between baseline and PTX states in this small patient group. Future studies are needed to evaluate this technique in a wider population.

  16. [Maternal-fetal transmission of HIV].

    Science.gov (United States)

    Gillet, J Y; Bongain, A; Monpoux, F; Mariani, R

    1995-02-01

    HIV infection in children is mainly the result of a mother-to-child transmission. The contamination during pregnancy is well known but intrapartum vertical transmission may also occur through ascending infection, blood exchange between mother and child, or direct contact with vaginal or cervical secretions. In addition HIV can be transmitted via breast milk. The reported rates of vertical transmission are highly variable: 14.4% in a European study, 18.3% in a French survey, 20 to 25% in the USA, 35 to 50% in Africa. It is unclear whether such a large variation of the rate of transmission is due to methodological differences or to different distributions of risk factors in the populations. There are some known predictive factors of HIV transmission such as low CD4 cells count, positive p24 antigenaemia and elevated concentrations of virus. The role of other factors is still debated: prematurity, virus (CMV, HTLV-1, HVB, HVC), C section prior labour, rupture of membranes. The prevention of HIV infection in infants is mainly based on contra-indication of pregnancy in infected women, desinfection of the vagina at the beginning of labour, early protection of the newborn by avoiding skin lesions and immediate washing, preventive treatment by zidovudin during pregnancy.

  17. Transmission fingerprints in quasiperiodic magnonic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, I.P. [Departamento de Ensino Superior, Instituto Federal de Educacao, Ciencia e Tecnologia do Maranhao, Imperatriz-MA 65919-050 (Brazil); Departamento de Fisica, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil); Vasconcelos, M.S. [Escola de Ciencias e Tecnologia, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil); Bezerra, C.G., E-mail: cbezerra@dfte.ufrn.br [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil)

    2011-12-15

    In this paper we investigated the influence of mirror symmetry on the transmission spectra of quasiperiodic magnonic multilayers arranged according to Fibonacci, Thue-Morse and double period quasiperiodic sequences. We consider that the multilayers composed of two simple cubic Heisenberg ferromagnets with bulk exchange constants J{sub A} and J{sub B} and spin quantum numbers S{sub A} and S{sub B}, respectively. The multilayer structure is surrounded by two semi-infinite slabs of a third Heisenberg ferromagnetic material with exchange constant J{sub C} and spin quantum number S{sub C}. For simplicity, the lattice constant has the same value a in each material, corresponding to epitaxial growth at the interfaces. The transfer matrix treatment was used for the exchange-dominated regime, taking into account the random phase approximation (RPA). Our numerical results illustrate the effects of mirror symmetry on (i) transmission spectra and (ii) transmission fingerprints. - Highlights: > We model quasiperiodic magnetic multilayers presenting mirror symmetry. > We investigated the allowed and forbidden bands of magnonic transmission. > Transmission return maps show the influence of mirror symmetry. > Mirror symmetry has no effect on the Fibonacci case. > Mirror symmetry does have effect on the Thue-Morse and double period cases.

  18. Transmission network expansion planning under deliberate outages

    Energy Technology Data Exchange (ETDEWEB)

    Alguacil, Natalia; Carrion, Miguel; Arroyo, Jose Manuel [E.T.S. de Ingenieros Industriales, Universidad de Castilla - La Mancha, Campus Universitario s/n, 13071 Ciudad Real (Spain)

    2009-10-15

    The reasons why the transmission network is a potentially attractive target for deliberate outages are twofold: (i) its crucial importance as a critical infrastructure for the society welfare, and (ii) its high level of vulnerability due to the current operation close to its static and dynamic limits. This new context where destructive agents come into play has been recognized by several agencies in Europe and North America, and various initiatives have been launched worldwide in order to assess and mitigate the vulnerability of transmission. Within this framework, this paper proposes the reinforcement and expansion of the transmission network as a way of mitigating the impact of increasingly plausible deliberate outages. The network planner selects the new lines to be built accounting not only for economic issues, as traditionally done, but also for the vulnerability of the transmission network against a set of credible intentional outages. The resulting vulnerability- and economic-constrained transmission expansion planning problem is formulated as a mixed-integer linear program. A number of case studies numerically illustrate the tradeoff between economic- and vulnerability-related issues and its impact on the expansion plans. In addition, we compare the results with those achieved by a traditional expansion planning model based on cost minimization. (author)

  19. Layered transmission of audio/video signals

    Science.gov (United States)

    Sajadieh, Masoud; Kschischang, F. R.; Leon-Garcia, Alberto

    1996-02-01

    In a broadcast channel, a single transmitter communicates with a number of receivers having different channel capacities available to them. A typical example of such a channel is the over the air TV broadcast. For the two-receiver case, we examine the performance of some common orthogonal transmission methods in terms of their achievable rates. Layered transmission, whereby the information intended for the better channel is superimposed on the portion of information common to both receivers, can provide an optimal solution. On this premise, we construct a bi-rate transmission model for a Gaussian broadcast channel, in which receivers are distributed according to an exponential pdf. A basic grade of service is thus maintained throughout the entire coverage area in addition to a higher quality video offered to the receivers with better reception conditions. The performance evaluation indicates that this model offers a higher per capita data rate comparing to the conventional single rate transmission systems. The multirate paradigm exhibits a stepwise degradation, mitigating the sharp cutoff threshold of the current digital broadcast systems. Application of this multirate broadcast proves very promising in the area of multiresolution transmission of digital HDTV.

  20. Image compression and transmission based on LAN

    Science.gov (United States)

    Huang, Sujuan; Li, Yufeng; Zhang, Zhijiang

    2004-11-01

    In this work an embedded system is designed which implements MPEG-2 LAN transmission of CVBS or S-video signal. The hardware consists of three parts. The first is digitization of analog inputs CVBS or S-video (Y/C) from TV or VTR sources. The second is MPEG-2 compression coding primarily performed by a MPEG-2 1chip audio/video encoder. Its output is MPEG-2 system PS/TS. The third part includes data stream packing, accessing LAN and system control based on an ARM microcontroller. It packs the encoded stream into Ethernet data frames and accesses LAN, and accepts Ethernet data packets bearing control information from the network and decodes corresponding commands to control digitization, coding, and other operations. In order to increase the network transmission rate to conform to the MEPG-2 data stream, an efficient TCP/IP network protocol stack is constructed directly from network hardware provided by the embedded system, instead of using an ordinary operating system for embedded systems. In the design of the network protocol stack to obtain a high LAN transmission rate on a low-end ARM, a special transmission channel is opened for the MPEG-2 stream. The designed system has been tested on an experimental LAN. The experiment shows a maximum LAN transmission rate up to 12.7 Mbps with good sound and image quality, and satisfactory system reliability.

  1. Transmission Line Adapted Analytical Power Charts Solution

    Science.gov (United States)

    Sakala, Japhet D.; Daka, James S. J.; Setlhaolo, Ditiro; Malichi, Alec Pulu

    2016-08-01

    The performance of a transmission line has been assessed over the years using power charts. These are graphical representations, drawn to scale, of the equations that describe the performance of transmission lines. Various quantities that describe the performance, such as sending end voltage, sending end power and compensation to give zero voltage regulation, may be deduced from the power charts. Usually required values are read off and then converted using the appropriate scales and known relationships. In this paper, the authors revisit this area of circle diagrams for transmission line performance. The work presented here formulates the mathematical model that analyses the transmission line performance from the power charts relationships and then uses them to calculate the transmission line performance. In this proposed approach, it is not necessary to draw the power charts for the solution. However the power charts may be drawn for the visual presentation. The method is based on applying derived equations and is simple to use since it does not require rigorous derivations.

  2. Frequent cross-species transmission of parvoviruses among diverse carnivore hosts

    Science.gov (United States)

    Allison, Andrew B.; Kohler, Dennis J.; Fox, Karen A.; Brown, Justin D.; Gerhold, Richard W.; Shearn-Bochsler, Valerie I.; Dubovi, Edward J.; Parrish, Colin R.; Holmes, Edward C.

    2013-01-01

    Although parvoviruses are commonly described in domestic carnivores, little is known about their biodiversity in nondomestic species. A phylogenetic analysis of VP2 gene sequences from puma, coyote, gray wolf, bobcat, raccoon, and striped skunk revealed two major groups related to either feline panleukopenia virus (“FPV-like”) or canine parvovirus (“CPV-like”). Cross-species transmission was commonplace, with multiple introductions into each host species but, with the exception of raccoons, relatively little evidence for onward transmission in nondomestic species.

  3. Fabrication and infrared-transmission properties of monolayer hexagonal-close-packed metallic nanoshells

    Science.gov (United States)

    Chen, Jing; Xu, Rongqing; Liu, Zhengqi; Tang, Chaojun; Chen, Zhuo; Wang, Zhenlin

    2013-06-01

    This paper presents a novel method for fabricating a monolayer of hexagonal-close-packed metallic nanoshells with a small opening, based on a combination of a porous polymer template and a nanocrystal-seeded electroless plating technique. Light transmission spectra of the metallic nanoshell arrays are measured, which show that light can transmit through the dense particle assemblies via excitations of a variety of surface-plasmons (SPs). Further numerical simulations confirm these transmission resonances and reveal that they are attributed to the excitations of localized quadrupolar spherelike and Fano-type hybridized SP modes supported by the specific structure. The present metallic microstructure could find applications in plasmonics.

  4. Assessing transmissibility of HIV-1 drug resistance mutations from treated and from drug-naive individuals

    Science.gov (United States)

    Winand, Raf; Theys, Kristof; Eusébio, Mónica; Aerts, Jan; Camacho, Ricardo J.; Gomes, Perpetua; Suchard, Marc A.; Vandamme, Anne-Mieke; Abecasis, Ana B.

    2015-01-01

    Objectives: Surveillance drug resistance mutations (SDRMs) in drug-naive patients are typically used to survey HIV-1-transmitted drug resistance (TDR). We test here how SDRMs in patients failing treatment, the original source of TDR, contribute to assessing TDR, transmissibility and transmission source of SDRMs. Design: This is a retrospective observational study analyzing a Portuguese cohort of HIV-1-infected patients. Methods: The prevalence of SDRMs to protease inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) in drug-naive and treatment-failing patients was measured for 3554 HIV-1 subtype B patients. Transmission ratio (prevalence in drug-naive/prevalence in treatment-failing patients), average viral load and robust linear regression with outlier detection (prevalence in drug-naive versus in treatment-failing patients) were analyzed and used to interpret transmissibility. Results: Prevalence of SDRMs in drug-naive and treatment-failing patients were linearly correlated, but some SDRMs were classified as outliers – above (PRO: D30N, N88D/S, L90 M, RT: G190A/S/E) or below (RT: M184I/V) expectations. The normalized regression slope was 0.073 for protease inhibitors, 0.084 for NRTIs and 0.116 for NNRTIs. Differences between SDRMs transmission ratios were not associated with differences in viral loads. Conclusion: The significant linear correlation between prevalence of SDRMs in drug-naive and in treatment-failing patients indicates that the prevalence in treatment-failing patients can be useful to predict levels of TDR. The slope is a cohort-dependent estimate of rate of TDR per drug class and outlier detection reveals comparative persistence of SDRMs. Outlier SDRMs with higher transmissibility are more persistent and more likely to have been acquired from drug-naive patients. Those with lower transmissibility have faster reversion dynamics after transmission and are associated with

  5. Combining epidemiological and genetic networks signifies the importance of early treatment in HIV-1 transmission.

    Science.gov (United States)

    Zarrabi, Narges; Prosperi, Mattia; Belleman, Robert G; Colafigli, Manuela; De Luca, Andrea; Sloot, Peter M A

    2012-01-01

    Inferring disease transmission networks is important in epidemiology in order to understand and prevent the spread of infectious diseases. Reconstruction of the infection transmission networks requires insight into viral genome data as well as social interactions. For the HIV-1 epidemic, current research either uses genetic information of patients' virus to infer the past infection events or uses statistics of sexual interactions to model the network structure of viral spreading. Methods for a reliable reconstruction of HIV-1 transmission dynamics, taking into account both molecular and societal data are still lacking. The aim of this study is to combine information from both genetic and epidemiological scales to characterize and analyse a transmission network of the HIV-1 epidemic in central Italy.We introduce a novel filter-reduction method to build a network of HIV infected patients based on their social and treatment information. The network is then combined with a genetic network, to infer a hypothetical infection transmission network. We apply this method to a cohort study of HIV-1 infected patients in central Italy and find that patients who are highly connected in the network have longer untreated infection periods. We also find that the network structures for homosexual males and heterosexual populations are heterogeneous, consisting of a majority of 'peripheral nodes' that have only a few sexual interactions and a minority of 'hub nodes' that have many sexual interactions. Inferring HIV-1 transmission networks using this novel combined approach reveals remarkable correlations between high out-degree individuals and longer untreated infection periods. These findings signify the importance of early treatment and support the potential benefit of wide population screening, management of early diagnoses and anticipated antiretroviral treatment to prevent viral transmission and spread. The approach presented here for reconstructing HIV-1 transmission networks

  6. High resolution transmission spectroscopy as a diagnostic for Jovian exoplanet atmospheres: constraints from theoretical models

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); Perna, Rosalba [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Heng, Kevin, E-mail: kemptone@grinnell.edu [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2014-11-01

    We present high resolution transmission spectra of giant planet atmospheres from a coupled three-dimensional (3D) atmospheric dynamics and transmission spectrum model that includes Doppler shifts which arise from winds and planetary motion. We model Jovian planets covering more than two orders of magnitude in incident flux, corresponding to planets with 0.9-55 day orbital periods around solar-type stars. The results of our 3D dynamical models reveal certain aspects of high resolution transmission spectra that are not present in simple one-dimensional (1D) models. We find that the hottest planets experience strong substellar to anti-stellar (SSAS) winds, resulting in transmission spectra with net blueshifts of up to 3 km s{sup –1}, whereas less irradiated planets show almost no net Doppler shifts. We find only minor differences between transmission spectra for atmospheres with temperature inversions and those without. Compared to 1D models, peak line strengths are significantly reduced for the hottest atmospheres owing to Doppler broadening from a combination of rotation (which is faster for close-in planets under the assumption of tidal locking) and atmospheric winds. Finally, high resolution transmission spectra may be useful in studying the atmospheres of exoplanets with optically thick clouds since line cores for very strong transitions should remain optically thick to very high altitude. High resolution transmission spectra are an excellent observational test for the validity of 3D atmospheric dynamics models, because they provide a direct probe of wind structures and heat circulation. Ground-based exoplanet spectroscopy is currently on the verge of being able to verify some of our modeling predictions, most notably the dependence of SSAS winds on insolation. We caution that interpretation of high resolution transmission spectra based on 1D atmospheric models may be inadequate, as 3D atmospheric motions can produce a noticeable effect on the absorption

  7. 77 FR 32183 - Transmission Planning and Cost Allocation by Transmission Owning and Operating Public Utilities

    Science.gov (United States)

    2012-05-31

    ... to Consideration of 195 Transmission Needs Driven by Public Policy Requirements i. Requests for... Clarification..... 235 c. Commission Determination 263 3. Consideration of Transmission Needs Driven by 302... Commission Did Not Show 551 That Existing Rates Are Unjust and Unreasonable 3. Commission Determination 555...

  8. 77 FR 64890 - Transmission Planning and Cost Allocation by Transmission Owning and Operating Public Utilities

    Science.gov (United States)

    2012-10-24

    .... Consideration of Transmission Needs Driven by 28 Public Policy Requirements B. Nonincumbent Transmission... followed or if a cost allocation method was not followed or produced unjust and unreasonable results for a.... 1000 compliance filings process and make a decision based on the record before us. 3. Consideration...

  9. Association of HIV transmissions and non-transmission knowledge with negative attitudes to HIV/AIDS

    Institute of Scientific and Technical Information of China (English)

    WEN Yu-feng; WANG Hua-dong; ZHAO Cun-xi; YAO Ying-shui; YE Dong-qing; JIANG Zuo-jun

    2011-01-01

    Background Human immunodeficiency virus/acquired immure deficiency syndrome (HIV/AIDS)-related stigma is an obstacle to the implementation of treatment, care, and support programs for people living with HIV/AIDS. This study explored the association of the HIV knowledge with the attitudes toward HIV/AIDS.Methods A cross-sectional survey was conducted in HIV epidemic rural areas with 5355 participants. Their knowledge and attitudes about HIV/AIDS were assessed, and the associations of HIV transmission and non-transmission knowledge with negative attitudes towards the HIV/AIDS were analyzed.Results Negative attitudes were significantly correlated with the HIV non-transmission knowledge and the correlation was higher than that with HIV transmission knowledge among participants who were male, 20 years old and migrant workers, students and respondents of and above junior high school. However, among those who were female, age 30 and older, illiterate with primary school education, negative attitudes were significantly associated with HIV non-transmission knowledge and the association was lower than that with HIV transmission knowledge.Conclusions HIV transmission knowledge and non-transmission knowledge have different influences on negative attitudes towards HIV/AIDS among different demographic subgroups.

  10. Value transmissions between parents and children: Gender and developmental phase as transmission belts

    NARCIS (Netherlands)

    Roest, A.M.C.; Dubas, J.S.; Gerris, J.R.M.

    2010-01-01

    This study applied the gender role model of socialization theory. the developmental aging theory, and the topic salience perspective to the investigation of parent-child value transmissions Specifically, we examined whether the bi-directionality and selectivity of value transmissions differed as a f

  11. Transmission of caprine herpesvirus 2 in domestic goats.

    Science.gov (United States)

    Li, Hong; Keller, Janice; Knowles, Donald P; Taus, Naomi S; Oaks, J Lindsay; Crawford, Timothy B

    2005-04-25

    Caprine herpesvirus 2 (CpHV-2) is a recently recognized gammaherpesvirus that is endemic in domestic goats and has been observed to cause clinical malignant catarrhal fever (MCF) in certain species of deer. In this study, transmission of CpHV-2 in goats was examined. A total of 30 kids born to a CpHV-2 positive goat herd were selected and divided into two groups: group 1 (n=16) remained in the positive herd; group 2 (n=14) was separated from the herd at 1 week of age after obtaining colostrum. Peripheral blood samples from each kid were examined regularly by competitive ELISA for MCF viral antibody and by PCR for CpHV-2 DNA. Fifteen out of 16 goats (94%) that remained with the positive herd seroconverted and became PCR-positive for CpHV-2 by 10 months of age. In contrast, all kids (100%) that were separated from the positive herd at 1 week of age remained negative until termination of the experiment at 1 year of age. Additional transmission experiments revealed that all CpHV-2-free adult goats were susceptible to CpHV-2 or ovine herpesvirus 2 (OvHV-2) infection. The data indicate that the transmission pattern of CpHV-2 in goats is similar to the pattern of OvHV-2 in sheep and that CpHV-2-free goats can be established by early separation of kids from positive herds, which has significant implications for MCF control programs.

  12. Spatial outline of malaria transmission in Iran

    Institute of Scientific and Technical Information of China (English)

    Mohammad Barati; Hossein Keshavarz-valian; Majid Habibi-nokhandan; Ahmad Raeisi; Leyla Faraji; Abdoreza Salahi-moghaddam

    2012-01-01

    Objective: To conduct for modeling spatial distribution of malaria transmission in Iran. Methods: Records of all malaria cases from the period 2008-2010 in Iran were retrieved for malaria control department, MOH&ME. Metrological data including annual rainfall, maximum and minimum temperature, relative humidity, altitude, demographic, districts border shapefiles, and NDVI images received from Iranian Climatologic Research Center. Data arranged in ArcGIS. Results:Results: 99.65%of malaria transmission cases were focused in southeast part of Iran. These transmissions had statistically correlation with altitude (650 m), maximum (30℃), minimum (20℃) and average temperature (25.3℃). Statistical correlation and overall relationship between NDVI (118.81), relative humidity (≥45%) and rainfall in southeast area was defined and explained in this study. Conclusions: According to ecological condition and mentioned cut-off points, predictive map was generated using cokriging method.

  13. Twisted Light Transmission over 143 kilometers

    CERN Document Server

    Krenn, Mario; Fink, Matthias; Fickler, Robert; Ursin, Rupert; Malik, Mehul; Zeilinger, Anton

    2016-01-01

    Spatial modes of light can potentially carry a vast amount of information, making them promising candidates for both classical and quantum communication. However, the distribution of such modes over large distances remains difficult. Intermodal coupling complicates their use with common fibers, while free-space transmission is thought to be strongly influenced by atmospheric turbulence. Here we show the transmission of orbital angular momentum modes of light over a distance of 143 kilometers between two Canary Islands, which is 50 times greater than the maximum distance achieved previously. As a demonstration of the transmission quality, we use superpositions of these modes to encode a short message. At the receiver, an artificial neural network is used for distinguishing between the different twisted light superpositions. The algorithm is able to identify different mode superpositions with an accuracy of more than 80% up to the third mode order, and decode the transmitted message with an error rate of 8.33%....

  14. Transmission Electron Microscopy Physics of Image Formation

    CERN Document Server

    Kohl, Helmut

    2008-01-01

    Transmission Electron Microscopy: Physics of Image Formation presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fifth edition includes discussion of recent progress, especially in the area of aberration correction and energy filtering; moreover, the topics introduced in the fourth edition have been updated. Transmission Electron Microscopy: Physics of Image Formation is written f...

  15. Wideband optical transmission properties of seven thermoplastics.

    Science.gov (United States)

    Lytle, J D; Wilkerson, G W; Jaramillo, J G

    1979-06-01

    Transmission measurements were made on samples of acrylic, polystyrene, styrene-acrylic copolymer (N.A.S.), polymethyl pentene (TPX), polysulfone, polycarbonate, and Trogamid; molded windows of 5.08-mm thickness were measured over the range 0.4-40.0 microm. All these injection-moldable materials appear to be usable in the visible region, and have surprisingly similar transmission profiles from 1.0 microm to 2.0 microm. Polystyrene and TPX possess several potentially useful transmission windows in the middle-wavelength and long-wavelength infrared regions, particularly TPX. The potential of these materials as substitutes for expensive crystalline materials in infrared application is discussed. The possibility that other thermoplastic materials may offer similar opportunities is also presented.

  16. Neutron transmission and capture of 241Am

    Directory of Open Access Journals (Sweden)

    Sage C.

    2013-03-01

    Full Text Available A set of neutron transmission and capture experiments based on the Time Of Flight (TOF technique, were performed in order to determine the 241Am capture cross section in the energy range from 0.01 eV to 1 keV. The GELINA facility of the Institute for Reference Materials and Measurements (IRMM served as the neutron source. A pair of C6D6 liquid scintillators was used to register the prompt gamma rays emerging from the americium sample, while a Li-glass detector was used in the transmission setup. Results from the capture and transmission data acquired are consistent with each other, but appear to be inconsistent with the evaluated data files. Resonance parameters have been derived for the data up to the energy of 100 eV.

  17. Enhanced Transmission through the Nanoparticle Coat

    Energy Technology Data Exchange (ETDEWEB)

    Song, G; Yu, L; Liu, B; Li, T, E-mail: candlesinwind@gmail.com [School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876 (China)

    2011-02-01

    By using the full-vectorial three-dimensional finite-difference time-domain method and the perfect electronic conductor as the materials, we studied the enhanced transmission spectra through a substrate with the perfect electronic conductor nanoparticle coat. Single metal nanoparticle exhibited characteristic localized surface plasmon modes. By placing more plasmonic nanoparticles close to each other to make up of a plane, it was possible to observe the interaction between the modes of each individual nanostructure. The results showed that the enhanced transmission spectra through a substrate with different nanoparticle coats which were made by different numbers of the layers or by different metals exhibited different peaks whose values could reach 1. The number of the nanoparticle coat layers influenced the number and the positions of the enhanced transmission peaks.

  18. Molecular Modeling of Prion Transmission to Humans

    Directory of Open Access Journals (Sweden)

    Etienne Levavasseur

    2014-10-01

    Full Text Available Using different prion strains, such as the variant Creutzfeldt-Jakob disease agent and the atypical bovine spongiform encephalopathy agents, and using transgenic mice expressing human or bovine prion protein, we assessed the reliability of protein misfolding cyclic amplification (PMCA to model interspecies and genetic barriers to prion transmission. We compared our PMCA results with in vivo transmission data characterized by attack rates, i.e., the percentage of inoculated mice that developed the disease. Using 19 seed/substrate combinations, we observed that a significant PMCA amplification was only obtained when the mouse line used as substrate is susceptible to the corresponding strain. Our results suggest that PMCA provides a useful tool to study genetic barriers to transmission and to study the zoonotic potential of emerging prion strains.

  19. A transmission calibration method for superconducting resonators

    CERN Document Server

    Cataldo, Giuseppe; Barrentine, Emily M; Brown, Ari D; Moseley, Samuel H; U-Yen, Kongpop

    2014-01-01

    A method is proposed and experimentally explored for \\textit{in-situ} calibration of complex transmission data for superconducting microwave resonators. This cryogenic calibration method accounts for the instrumental transmission response between the vector network analyzer reference plane and the device calibration plane. Once calibrated, the observed resonator response was modeled in detail by two approaches. The first, a phenomenological model based on physically realizable rational functions, enables the extraction of multiple resonance frequencies and widths for coupled resonators without explicit specification of the circuit network. In the second, an ABCD-matrix representation for the distributed transmission line circuit is used to model the observed response from the characteristic impedance and propagation constant. When used in conjunction with electromagnetic simulations, the kinetic inductance fraction can be determined with this method with an accuracy of 2%. Datasets for superconducting microst...

  20. Storage, transmission and distribution of hydrogen

    Science.gov (United States)

    Kelley, J. H.; Hagler, R., Jr.

    1979-01-01

    Current practices and future requirements for the storage, transmission and distribution of hydrogen are reviewed in order to identify inadequacies to be corrected before hydrogen can achieve its full potential as a substitute for fossil fuels. Consideration is given to the storage of hydrogen in underground solution-mined salt caverns, portable high-pressure containers and dewars, pressure vessels and aquifers and as metal hydrides, hydrogen transmission in evacuated double-walled insulated containers and by pipeline, and distribution by truck and internal distribution networks. Areas for the improvement of these techniques are indicated, and these technological deficiencies, including materials development, low-cost storage and transmission methods, low-cost, long-life metal hydrides and novel methods for hydrogen storage, are presented as challenges for research and development.