564 research outputs found

    Harmonic analysis on the Möbius gyrogroup

    Get PDF
    In this paper we propose to develop harmonic analysis on the Poincaré ball BtnB_t^n, a model of the n-dimensional real hyperbolic space. The Poincaré ball BtnB_t^n is the open ball of the Euclidean n-space RnR^n with radius t>0t>0, centered at the origin of RnR^n and equipped with Möbius addition, thus forming a Möbius gyrogroup where Möbius addition in the ball plays the role of vector addition in Rn\mathbb{R}^n. For any t>0t>0 and an arbitrary parameter σR\sigma \in R we study the (σ,t)(\sigma,t)-translation, the (σ,t)( \sigma,t)-convolution, the eigenfunctions of the (σ,t)(\sigma,t)-Laplace-Beltrami operator, the (σ,t)(\sigma,t)-Helgason Fourier transform, its inverse transform and the associated Plancherel's Theorem, which represent counterparts of standard tools, thus, enabling an effective theory of hyperbolic harmonic analysis. Moreover, when t+t \rightarrow +\infty the resulting hyperbolic harmonic analysis on BtnB_t^n tends to the standard Euclidean harmonic analysis on RnR^n, thus unifying hyperbolic and Euclidean harmonic analysis. As an application we construct diffusive wavelets on BtnB_t^n

    Occurrence and distribution of pepper veinal mottle virus and cucumber mosaic virus in pepper in Ibadan, Nigeria

    Get PDF
    Viral diseases constitute obstacles to pepper production in the world. In Nigeria, pepper plants are primarily affected by pepper veinal mottle virus (PVMV), Cucumber mosaic virus (CMV), Pepper leaf curl Virus (TLCV), Tobacco mosaic virus (TMV), Pepper mottle virus (PMV) and a host of other viruses. The experiment was carried out with a diagnostic survey on the experimental field of the National Horticultural Research Institute, Ibadan, Nigeria and on pepper farms in six local government areas within Ibadan Oyo State, Nigeria, forty samples were collected from each of the farms. Diseased samples were obtained from the field and taken to the laboratory for indexing. In ELISA test some of the samples from the pepper farms showed positive reaction to single infection with PVMV (36.79%), CMV (22.14%) while some others showed positive reaction to mixed infection of the two viruses (10%) but some also negative reaction to PVMV and CMV antisera (31.07)

    Non-small cell lung carcinoma in an adolescent manifested by acute paraplegia due to spinal metastases: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Bronchial carcinomas in childhood and adolescence are extremely rare; only individual cases have been reported previously.</p> <p>Case presentation</p> <p>We report on a 16-year-old Caucasian German boy with non-small cell lung carcinoma (squamous cell non-small cell lung carcinoma) stage IV, T4N2M1, without epidermal growth factor receptor overexpression and/or mutation or k-ras mutation. He presented with paraplegia due to spinal metastases of the bronchial carcinoma. No familial predisposition or toxin exposure was identified. Treatment following adult protocols consisted of surgical intervention for spinal metastases, first-line cisplatinum and gemcitabine, irradiation and second-line docetaxel. After a transient response our patient experienced disease progression and died about 10 months later.</p> <p>Conclusion</p> <p>Response and survival in our 16-year-old patient were similar to adult patients with stage IV non-small cell lung carcinoma.</p

    Determination of nitric oxide metabolites, nitrate and nitrite, in Anopheles culicifacies mosquito midgut and haemolymph by anion exchange high-performance liquid chromatography: plausible mechanism of refractoriness

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The diverse physiological and pathological role of nitric oxide in innate immune defenses against many intra and extracellular pathogens, have led to the development of various methods for determining nitric oxide (NO) synthesis. NO metabolites, nitrite (NO<sub>2</sub><sup>-</sup>) and nitrate (NO<sub>3</sub><sup>-</sup>) are produced by the action of an inducible <it>Anopheles culicifacies </it>NO synthase (AcNOS) in mosquito mid-guts and may be central to anti-parasitic arsenal of these mosquitoes.</p> <p>Method</p> <p>While exploring a plausible mechanism of refractoriness based on nitric oxide synthase physiology among the sibling species of <it>An. culicifacies</it>, a sensitive, specific and cost effective high performance liquid chromatography (HPLC) method was developed, which is not influenced by the presence of biogenic amines, for the determination of NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>from mosquito mid-guts and haemolymph.</p> <p>Results</p> <p>This method is based on extraction, efficiency, assay reproducibility and contaminant minimization. It entails de-proteinization by centrifugal ultra filtration through ultracel 3 K filter and analysis by high performance anion exchange liquid chromatography (Sphereclone, 5 μ SAX column) with UV detection at 214 nm. The lower detection limit of the assay procedure is 50 pmoles in all midgut and haemolymph samples. Retention times for NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>in standards and in mid-gut samples were 3.42 and 4.53 min. respectively. Assay linearity for standards ranged between 50 n<it>M </it>and 1 m<it>M</it>. Recoveries of NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>from spiked samples (1–100 μ<it>M</it>) and from the extracted standards (1–100 μ<it>M</it>) were calculated to be 100%. Intra-assay and inter assay variations and relative standard deviations (RSDs) for NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>in spiked and un-spiked midgut samples were 5.7% or less. Increased levels NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>in midguts and haemolymph of <it>An. culicifacies </it>sibling species B in comparison to species A reflect towards a mechanism of refractoriness based on AcNOS physiology.</p> <p>Conclusion</p> <p>HPLC is a sensitive and accurate technique for identification and quantifying pmole levels of NO metabolites in mosquito midguts and haemolymph samples that can be useful for clinical investigations of NO biochemistry, physiology and pharmacology in various biological samples.</p

    Epidemiologic aspects of the malaria transmission cycle in an area of very low incidence in Brazil

    Get PDF
    BACKGROUND: Extra-Amazonian autochthonous Plasmodium vivax infections have been reported in mountainous regions surrounded by the Atlantic Forest in Espírito Santo state, Brazil. METHODS: Sixty-five patients and 1,777 residents were surveyed between April 2001 and March 2004. Laboratory methods included thin and thick smears, multiplex-PCR, immunofluorescent assay (IFA) against P. vivax and Plasmodium malariae crude blood-stage antigens and enzyme-linked immunosorbent assay (ELISA) for antibodies against the P. vivax-complex (P. vivax and variants) and P. malariae/Plasmodium brasilianum circumsporozoite-protein (CSP) antigens. RESULTS: Average patient age was 35.1 years. Most (78.5%) were males; 64.6% lived in rural areas; 35.4% were farmers; and 12.3% students. There was no relevant history of travel. Ninety-five per cent of the patients were experiencing their first episode of malaria. Laboratory data from 51 patients were consistent with P. vivax infection, which was determined by thin smear. Of these samples, 48 were assayed by multiplex-PCR. Forty-five were positive for P. vivax, confirming the parasitological results, while P. malariae was detected in one sample and two gave negative results. Fifty percent of the 50 patients tested had IgG antibodies against the P. vivax-complex or P. malariae CSP as determined by ELISA. The percentages of residents with IgM and IgG antibodies detected by IFA for P. malariae, P. vivax and Plasmodium falciparum who did not complain of malaria symptoms at the time blood was collected were 30.1% and 56.5%, 6.2% and 37.7%, and 13.5% and 13%, respectively. The same sera that reacted to P. vivax also reacted to P. malariae. The following numbers of samples were positive in multiplex-PCR: 23 for P. vivax; 15 for P. malariae; 9 for P. falciparum and only one for P. falciparum and P. malariae. All thin and thick smears were negative. ELISA against CSP antigens was positive in 25.4%, 6.3%, 10.7% and 15.1% of the samples tested for "classical" P. vivax (VK210), VK247, P. vivax-like and P. malariae, respectively. Anopheline captures in the transmission area revealed only zoophilic and exophilic species. CONCLUSION: The low incidence of malaria cases, the finding of asymptomatic inhabitants and the geographic separation of patients allied to serological and molecular results raise the possibility of the existence of a simian reservoir in these areas

    Competing Interactions in DNA Assembly on Graphene

    Get PDF
    We study the patterns that short strands of single-stranded DNA form on the top graphene surface of graphite. We find that the DNA assembles into two distinct patterns, small spherical particles and elongated networks. Known interaction models based on DNA-graphene binding, hydrophobic interactions, or models based on the purine/pyrimidine nature of the bases do not explain our observed crossover in pattern formation. We argue that the observed assembly behavior is caused by a crossover in the competition between base-base pi stacking and base-graphene pi stacking and we infer a critical crossover energy of eV. The experiments therefore provide a projective measurement of the base-base interaction strength

    Competency of Anopheles stephensi mysorensis strain for Plasmodium vivax and the role of inhibitory carbohydrates to block its sporogonic cycle

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Despite the abundance of studies conducted on the role of mosquitoes in malaria transmission, the biology and interaction of <it>Plasmodium </it>with its insect host still holds many mysteries. This paper provides the first study to follow the sporogonic cycle of <it>Plasmodium vivax </it>in a wild insecticide-resistant mysorensis strain of <it>Anopheles stephensi</it>, a major vector of vivax malaria in south-eastern Iran. The study subsequently demonstrates that host-parasite sugar binding interactions are critical to the development of this parasite in the salivary glands of its mosquito host. The identity of the receptors or sugars involved was revealed by a receptor "pre-saturation" strategy in which sugars fed to the mosquitoes inhibited normal host-parasite interactions.</p> <p>Methods</p> <p><it>Anopheles stephensi </it>mysorensis mosquitoes were artificially infected with <it>P. vivax </it>by feeding on the blood of gametocytaemic volunteers reporting to local malaria clinics in the Sistan-Baluchistan province of south-eastern Iran. In order to determine the inhibitory effect of carbohydrates on sporogonic development, vector mosquitoes were allowed to ingest blood meals containing both gametocytes and added carbohydrates. The carbohydrates tested were GlcNAc, GalNAc, arabinose, fucose, mannose, lactose, glucose and galactose. Sporogonic development was assessed by survival of the parasite at both the oocyst and sporozoite stages.</p> <p>Results</p> <p>Oocyst development was observed among nearly 6% of the fed control mosquitoes but the overall number of mosquitoes exhibiting sporozoite invasion of the salivary glands was 47.5% lower than the number supporting oocysts in their midgut. Of the tested carbohydrates, only arabinose and fucose slightly perturbed the development of <it>P. vivax </it>oocysts at the basal side of the mosquito midgut, and the remaining sugars caused no reductions in oocyst development. Strikingly however, sporozoites were completely absent from the salivary glands of mosquitoes treated with mannose, GalNAc, and lactose.</p> <p>Conclusion</p> <p>The study indicates that <it>An. stephensi </it>in southern Iran has the potential to survive long enough to be re-infected and transmit vivax malaria several times, based on the average adult female longevity (about 30 days) and its gonotrophic cycle (2–3 days) during the malaria transmission season. Certain sugar binding interactions are important for the development of <it>P. vivax </it>sporozoites, and this information may be instrumental for the development of transmission blocking strategies.</p

    Using computer-aided detection in mammography as a decision support

    Get PDF
    Contains fulltext : 87548.pdf (publisher's version ) (Closed access)OBJECTIVE: To evaluate an interactive computer-aided detection (CAD) system for reading mammograms to improve decision making. METHODS: A dedicated mammographic workstation has been developed in which readers can probe image locations for the presence of CAD information. If present, CAD findings are displayed with the computed malignancy rating. A reader study was conducted in which four screening radiologists and five non-radiologists participated to study the effect of this system on detection performance. The participants read 120 cases of which 40 cases had a malignant mass that was missed at the original screening. The readers read each mammogram both with and without CAD in separate sessions. Each reader reported localized findings and assigned a malignancy score per finding. Mean sensitivity was computed in an interval of false-positive fractions less than 10%. RESULTS: Mean sensitivity was 25.1% in the sessions without CAD and 34.8% in the CAD-assisted sessions. The increase in detection performance was significant (p = 0.012). Average reading time was 84.7 +/- 61.5 s/case in the unaided sessions and was not significantly higher when interactive CAD was used (85.9 +/- 57.8 s/case). CONCLUSION: Interactive use of CAD in mammography may be more effective than traditional CAD for improving mass detection without affecting reading time.1 oktober 201
    corecore