772 research outputs found

    Survivability of Vibrio parahaemolyticus in satar and otak-otak, Malaysian fish-based street food

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    Street food is popular in Asia due to its availability, low price and good taste. The safety of street food has been always questionable due to its poor handling which probably leads to microbial contamination. The objective of this study was to determine the surviving quantities of V. parahaemolyticus under various conditions in street-vended food, namely satar and otak-otak after anticipated cross-contamination to support policy and regulatory documents. The satar and otak-otak were prepared from minced and unminced fish flesh, respectively, together with other ingredients. Each satar and otak-otak were prepared with 0, 0.5, 1.5 and 3% of sodium chloride (NaCl), respectively. V. parahaemolyticus inoculum at approximately 8.66 log CFU/ml were inoculated into the samples and incubated for up to 6 h. Samples were taken at 0, 1, 3 and 6 h for enumeration of V. parahaemolyticus using spread plate method on Thiosulphate Citrate Bile Salts Sucrose (TCBS) agar. For control samples, V. parahaemolyticus was not immediately inactivated in distilled water even though significant better survivability was observed in Phosphate Buffer Saline (PBS). The numbers of V. parahaemolyticus was found to decrease by varying amounts based on the salt content and duration of holding. However, significant amounts survived to indicate potential risk

    Retinal Changes in a Mutant Form of Goldfish with Megalophthalmia

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    The retinal changes of a mutant strain of goldfish with megalophthalmia were studied by histology, electron microscopy and biochemistry. Changes in the morphology of the pigment epithelium, decrease in number of photoreceptors, thinning out of retinal layers and the existence of spaces in the retina were all features as the eyes grew in size. Invasion of macrophages was also evident in the retina. A decrease in leucine uptake per milligram of retina was also detected as the eye grew beyond 0.8 millilitre in volume. These changes, although related to volume changes (i.e., growth) of the eyes, were found to have little relationship with increase of intraocular pressure as intraocular pressures in the growing eyes of the mutant strain did not change much. Goldfish from a control strain with similar eye volumes and sizes (ages) were used for comparison and similar changes as in the mutant were not apparent

    Higher-order nonlinear modes and bifurcation phenomena due to degenerate parametric four-wave mixing

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    We demonstrate that weak parametric interaction of a fundamental beam with its third harmonic field in Kerr media gives rise to a rich variety of families of non-fundamental (multi-humped) solitary waves. Making a comprehensive comparison between bifurcation phenomena for these families in bulk media and planar waveguides, we discover two novel types of soliton bifurcations and other interesting findings. The later includes (i) multi-humped solitary waves without even or odd symmetry and (ii) multi-humped solitary waves with large separation between their humps which, however, may not be viewed as bound states of several distinct one-humped solitons.Comment: 9 pages, 17 figures, submitted to Phys. Rev.

    Approximate solutions and scaling transformations for quadratic solitons

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    We study quadratic solitons supported by two- and three-wave parametric interactions in chi-2 nonlinear media. Both planar and two-dimensional cases are considered. We obtain very accurate, 'almost exact', explicit analytical solutions, matching the actual bright soliton profiles, with the help of a specially-developed approach, based on analysis of the scaling properties. Additionally, we use these approximations to describe the linear tails of solitary waves which are related to the properties of the soliton bound states.Comment: 11 pages, 9 figures; submitted for publicatio

    A topological insulator surface under strong Coulomb, magnetic and disorder perturbations

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    Three dimensional topological insulators embody a newly discovered state of matter characterized by conducting spin-momentum locked surface states that span the bulk band gap as demonstrated via spin-resolved ARPES measurements . This highly unusual surface environment provides a rich ground for the discovery of novel physical phenomena. Here we present the first controlled study of the topological insulator surfaces under strong Coulomb, magnetic and disorder perturbations. We have used interaction of iron, with a large Coulomb state and significant magnetic moment as a probe to \textit{systematically test the robustness} of the topological surface states of the model topological insulator Bi2_2Se3_3. We observe that strong perturbation leads to the creation of odd multiples of Dirac fermions and that magnetic interactions break time reversal symmetry in the presence of band hybridization. We also present a theoretical model to account for the altered surface of Bi2_2Se3_3. Taken collectively, these results are a critical guide in manipulating topological surfaces for probing fundamental physics or developing device applications.Comment: 14 pages, 4 Figures. arXiv admin note: substantial text overlap with arXiv:1009.621

    Computer-Aided Fabrication System Structure

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    Contains reports on one research project.Defense Advanced Research Projects Agency MDA 972 88-K-000

    Recurrent neck abscesses due to cervical tuberculous lymphadenopathy in an elderly woman post-splenectomy: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>There are approximately 7000 new cases of tuberculosis every year in the UK, the majority of which are pulmonary. Approximately 5% affect the lymph nodes in immunocompetent patients. Scrofula is an old term used to describe lymph nodes of the neck infected with tuberculosis</p> <p>Case presentation</p> <p>In the elderly population, growing neck lumps are always treated as red flags until a diagnosis is confirmed. Here, the case of an 89-year-old Caucasian woman is presented. She was reluctant to seek medical help as she feared the cause was sinister and did not want surgical intervention.</p> <p>Conclusion</p> <p>It is difficult to culture tuberculosis from superficial swabs, resulting in a high proportion of false negative results. Where there is a high degree of clinical suspicion for tuberculosis, it is important to consider a biopsy with culture. Patients over the age of 65 have waning immunity and are therefore a vulnerable group for acute infections as well as the re-activation of indolent organisms. Post-splenectomy patients are at a major disadvantage during sepsis and when a cellular immune response is required, such as when faced with a <it>Mycobacterium tuberculosis </it>infection. Scrofula is treated with a similar regime as pulmonary tuberculosis and has a near 100% success rate.</p
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