Impact of bidirectional relationships between streptococcus anginosus group and host tissue matrix components on cellular activity: Role in establishment of infection

This paper investigates pathogenic mechanisms of the Streptococcus anginosus group (SAG) of bacteria which influence the biological activity of periodontal ligament (PDL) cells, endothelial cells and also how matrix proteins produced by these host cells influence bacterial virulence factors. Isolates of SAG species, designated S. anginosus, S. constellatus and S. intermedius, were derived from healthy commensal and clinical pathogenic infection sites. SAG culture supernatants contained multiple protein components which differed between isolates. All SAG supernatants increased cellular proliferation and decreased decorin synthesis and collagen assembly by PDL cells and reduced endothelial cell migration. SAG isolates responded differently to extracellular matrix (ECM) components synthesised by PDL cells, but there was an overall notable increase in hydrolytic enzyme activity and in the production of the cytotoxin intermedilysin by S. intermedius. Collectively, the results indicate that both commensal and pathogenic SAG isolates were capable of impairing the ability of PDL cells and endothelial cells to make functional vascularised tissue. Reduced decorin synthesis is likely to have a major impact on cell signalling, angiogenesis and matrix assembly. Furthermore, ECM components produced by PDL cells were differentially capable of moderately increasing SAG enzymic activity, leading to subtle ECM modifications. The impact this bidirectional effect has on the tissue remodelling process is discussed

Electrostatic charge generation and buildup during contact and frictional electrification of woven textile fabrics

Woven textile fabrics of cotton, polyester, nylon and polypropylene have been tested for contact and frictional electrification under similar experimental conditions. These fabrics are contacted and rubbed with steel and polytetrafluoroethylene (PTFE) for investigating electrostatic charge generation and dissipation properties between polymer-metal and polymer-polymer materials. Measurements have been made for the charge buildup after first initial contact/rubbing; the charge buildup during 50 contact/rubbing cycles; and the half-life discharge time. It is observed that the charge generation during rubbing and contact with steel is less than that with PTFE. It is also observed that the samples charged by rubbing decay quickly as compared to the contact charged samples. The findings indicate that with a few exceptions, the charge magnitude and polarity follow the triboelectric series

PRELIMINARY RECONSTRUCTION OF DIET AT A NEOLITHIC SITE IN VIETNAM USING STABLE ISOTOPE AND BA/SR ANALYSES

In order to better evaluate the role plant exploitation played at a Neolithic site (Con Co Ngua, ceramic context dated to 5000 years BP) in Vietnam, we measured the 13C in apatite from human teeth at this site as well as from a nearby Metal Period site (Nui Nap), with a carbon date of 1670 years BP, where 13C and 15N from collagen were also measured. Ba:Sr ratios at both sites were determined in order to estimate the importance of marine versus agricultural food sources. Results are consistent with incipient plant exploitation at Con Co Ngua, while dietary C3 plants that might have included rice played a smaller role than at Nui Nap. Marine sources appear to be more significant at the earlier site

The mechanism of the air-jet texturing: the role of wetting, spin finish and friction in forming and fixing loops

A comprehensive review of the roles played by the airflow, wetting and spin finish on the air-jet texturing process is given. An experimental investigation of the air-jet texturing process using residual spin finish, yarn-to-yarn static and kinetic friction, filament strength, filament diameter, and on-line tension measurements and high-speed cine-photography is reported. Filament yarn motion in different regions of the texturing nozzle during dry and wet texturing is analysed. It is found that water acts as lubricant to reduce friction between the filaments in the wet texturing process as the filament yarn travels through the nozzle enabling easier relative motion of the filaments resulting in enhanced entanglement. Wet texturing also reduces spin finish on the yarn surface, which in turn, causes an increase in static friction between the filaments of the textured yarn resulting in better fixing of the loops and consequently superior yarns

Tuning of Human Modulation Filters Is Carrier-Frequency Dependent

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Impact of bidirectional relationships between streptococcus anginosus group and host tissue matrix components on cellular activity: Role in establishment of infection

This paper investigates pathogenic mechanisms of the Streptococcus anginosus group (SAG) of bacteria which influence the biological activity of periodontal ligament (PDL) cells, endothelial cells and also how matrix proteins produced by these host cells influence bacterial virulence factors. Isolates of SAG species, designated S. anginosus, S. constellatus and S. intermedius, were derived from healthy commensal and clinical pathogenic infection sites. SAG culture supernatants contained multiple protein components which differed between isolates. All SAG supernatants increased cellular proliferation and decreased decorin synthesis and collagen assembly by PDL cells and reduced endothelial cell migration. SAG isolates responded differently to extracellular matrix (ECM) components synthesised by PDL cells, but there was an overall notable increase in hydrolytic enzyme activity and in the production of the cytotoxin intermedilysin by S. intermedius. Collectively, the results indicate that both commensal and pathogenic SAG isolates were capable of impairing the ability of PDL cells and endothelial cells to make functional vascularised tissue. Reduced decorin synthesis is likely to have a major impact on cell signalling, angiogenesis and matrix assembly. Furthermore, ECM components produced by PDL cells were differentially capable of moderately increasing SAG enzymic activity, leading to subtle ECM modifications. The impact this bidirectional effect has on the tissue remodelling process is discussed

Education in the interregnum: an evaluation of Zygmunt Bauman’s liquid-turn writing on education

In his liquid-turn writings, Zygmunt Bauman has come to identify liquid\ud modernity as a period of interregnum. Education has a central role to\ud play within the contemporary interregnum by opening up a new public\ud sphere for dialogue. However, the processes of liquefaction manifest\ud themselves in conditions that severely limit a person’s ability to exercise\ud their human agency. Bauman provides no indication of how the\ud educators can escape the processes that limit agency, nor does he\ud explain how educators can combat the seductive consumerism that\ud students need to overcome before they can engage in a reconstruction of\ud the public sphere

Forward Masking Estimated by Signal Detection Theory Analysis of Neuronal Responses in Primary Auditory Cortex

Psychophysical forward masking is an increase in threshold of detection of a sound (probe) when it is preceded by another sound (masker). This is reminiscent of the reduction in neuronal responses to a sound following prior stimulation. Studies in the auditory nerve and cochlear nucleus using signal detection theory techniques to derive neuronal thresholds showed that in centrally projecting neurons, increases in masked thresholds were significantly smaller than the changes measured psychophysically. Larger threshold shifts have been reported in the inferior colliculus of awake marmoset. The present study investigated the magnitude of forward masking in primary auditory cortical neurons of anaesthetised guinea-pigs. Responses of cortical neurons to unmasked and forward masked tones were measured and probe detection thresholds estimated using signal detection theory methods. Threshold shifts were larger than in the auditory nerve, cochlear nucleus and inferior colliculus. The larger threshold shifts suggest that central, and probably cortical, processes contribute to forward masking. However, although methodological differences make comparisons difficult, the threshold shifts in cortical neurons were, in contrast to subcortical nuclei, actually larger than those observed psychophysically. Masking was largely attributable to a reduction in the responses to the probe, rather than either a persistence of the masker responses or an increase in the variability of probe responses