Typhoid fever

Christie, A. B.

doi:10.1136/pgmj.42.483.41

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…The optimum molding condition for the double-end-gated configuration is achieved at a higher melt temperature, but at a lower injection pressure than for the single-end-gated configuration. This reinforces the observation that increased melt temperature enhances weld line strength due to molecular diffusion and entanglement at high temperatures [20,21]. The reason for slightly lower injection pressures in the case of weld lines may be due to the levels of molded-in-stress building up at the melt fronts.…”

Section: Principal Process Factors Determinationsupporting

confidence: 85%

Weld lines in nylon 6 melt-blended nanocomposites

2005

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The effects of weld lines in injection moldings of nylon 6 and nylon 6 nanocomposite samples were investigated by comparing single-end-gated and double-end-gated tensile samples. The single-gated samples have no weld line, whereas the double-end-gated configuration produces a weld line at the center of the gauge length. Nylon 6 shows little variation in tensile properties for samples with or without weld lines, remaining ductile and tough, even with weld lines present. However, nylon 6 nanocomposites containing organically modified montmorillonite (organoclay), produced by a melt blending technique, exhibits rigid and brittle behavior for both single (no weld line) and double-end-gated (with weld line) samples. The organoclay increases the tensile strength but reduces the strain-to-failure significantly in both cases. A modified L 16 orthogonal array based on the Taguchi approach with three levels was designed to run injection-molding experiments to allow production of a modest number of samples to identify the most important process factors. The results were analyzed using the statistical tools signal-to-noise (S/N) ratio and analysis of variance (ANOVA), in particular showing that the principal process factors for the double-end-gated nylon 6 nanocomposite samples are mold and melt temperatures. POLYM. ENG. SCI., 45:1606 -1614, 2005.

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Section: Principal Process Factors Determinationsupporting

confidence: 85%

Weld lines in nylon 6 melt-blended nanocomposites

2005

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“…and for talc (1 5) invite two comments. First, while it may be possible to improve somewhat the weldline strength of double-gated moldings by controlling the filler aspect ratio or adhesion at the filler-matrix interface (8,9,11) the weldline will always be much weaker than other areas of the part as long as differences in filler orientation remain. Even in the most favorable case of the strong filler matrix interface, the local elastic modulus in the weldline zone will be much lower than elsewhere in the part (1 6).…”

Section: Double-gated Moldmentioning

confidence: 99%

Weldline integrity of reinforced plastics: Effect of filler shape

Fisa

Dufour²,

Vu‐Khanh³

1987

Polymer Composites

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The paper is a preliminary report on glass fiber and glass flake orientation in the weldline zone of injection molded reinforced polypropylene. Two types of weldlines were studied using simple shape molds: one where two melt streams meet head‐on and become immobilized, the other where the weldline formation is followed by additional flow. In the weldlines of the first type, which are characteristic of current standard molds used to test weldline strength, the anisometric particles are almost perfectly oriented perpendicular to flow. As a result, the weldlines of this type tend to be weak and brittle. In the second case when the weldline is formed by merging of melt streams separated by an insert, particle orientation in the weldline area remains different from other areas of the sample for long distances from the insert. It is shown that in molds where the weldline formation is followed by laterally expanding flow the change of particle orientation is faster than for unidirectional flow.

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“…Flagellin is highly immunogenic and antibodies (IgG) against S . Typhi flagellin can be measured for a prolonged period after a confirmed typhoid infection 15 . As the isogenic S .…”

Section: Resultsmentioning

confidence: 99%

The Hd, Hj, and Hz66 flagella variants of Salmonella enterica serovar Typhi modify host responses and cellular interactions

Schreiber

Kay

Frankel

et al. 2015

Sci Rep

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Salmonella Typhi, the causative agent of typhoid fever, is a monophyletic, human-restricted bacterium that exhibits limited phenotypic variation. S. Typhi from Indonesia are a notable exception, with circulating strains expressing diverse flagella antigens including Hj, Hd and Hz66. Hypothesizing that S. Typhi flagella plays a key role during infection, we constructed an S. Typhi fliC mutant and otherwise isogenic S. Typhi strains expressing the Hj, Hd, Hz66 flagella antigens. Phenotyping revealed differences in flagellum structure, strain motility and immunogenicity, but not in the ability of flagellated isolates to induce TLR5 activity. Invasion assays using epithelial and macrophage cell lines revealed differences in the ability of these S. Typhi derivatives to invade cells or induce cellular restructuring in the form of ruffles. Notably, the Hj variant induced substantial ruffles that were not fully dependent on the GTPases that contribute to this process. These data highlight important differences in the phenotypic properties of S. Typhi flagella variation and how they impact on the pathogenesis of S. Typhi.

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Typhoid fever

Cited by 5 publications

References 12 publications

Weld lines in nylon 6 melt-blended nanocomposites

Weld lines in nylon 6 melt-blended nanocomposites

Weldline integrity of reinforced plastics: Effect of filler shape

The Hd, Hj, and Hz66 flagella variants of Salmonella enterica serovar Typhi modify host responses and cellular interactions

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