On robustness against JPEG2000: a performance evaluation of wavelet-based watermarking techniques

With the emergence of new scalable coding standards, such as JPEG2000, multimedia is stored as scalable coded bit streams that may be adapted to cater network, device and usage preferences in multimedia usage chains providing universal multimedia access. These adaptations include quality, resolution, frame rate and region of interest scalability and achieved by discarding least significant parts of the bit stream according to the scalability criteria. Such content adaptations may also affect the content protection data, such as watermarks, hidden in the original content. Many wavelet-based robust watermarking techniques robust to such JPEG2000 compression attacks are proposed in the literature. In this paper, we have categorized and evaluated the robustness of such wavelet-based image watermarking techniques against JPEG2000 compression, in terms of algorithmic choices, wavelet kernel selection, subband selection, or watermark selection using a new modular framework. As most of the algorithms use a different set of parametric combination, this analysis is particularly useful to understand the effect of various parameters on the robustness under a common platform and helpful to design any such new algorithm. The analysis also considers the imperceptibility performance of the watermark embedding, as robustness and imperceptibility are two main watermarking properties, complementary to each other

Immunopathogenesis of chronic inflammatory periodontal disease: cellular and molecular mechanisms.

Recent studies of the cellular mechanisms involved in chronic inflammatory periodontal disease (CIPD) have contributed significantly to our understanding of the pathogenesis of the disease process. Functional studies have demonstrated polymorphonuclear neutrophil (PMN) chemotactic defects in some 70% of subjects with localized juvenile periodontitis while chemiluminescence data have suggested that periphertal blood PMNs from young subjects with adult periodontitis (AP) may be in a metabolically active state. Further studies have shown that stimulation of PMNs with a number of periodontopathic bacteria resulted in the production of an IL‐1 inhibitor suggesting a possible regulatory role for PMNs in CIPD in addition to their established protective role. Most work on the immunoregulation of CIPD has, however, concentrated on T‐cells. Recent limit dilution analysis has demonstrated the presence of periodontopathic bacteria‐specific T cells in peripheral blood and the involvement and homing of these cells to the local lesions of CIPD is currently the focus of many studies. In animal studies, Actinobacillus actinomycetemcomitans (Aa)‐specific T‐cell clones home to the gingival tissues where they may exert a protective role. Homing and retention of lymphocytes to and in specific sites is dependent upon the expression of adhesion molecules. Recent data indicate however, that while there are increasing levels of ICAM‐1, LECAM‐1 and PECAM‐1 expression with increasing degrees of inflammation, there are no differences between gingivitis and periodontitis lesions. Cytokine profiles may be related to the role of T‐cell clones homing to the gingiva in CIPD. In subjects susceptible to periodontal breakdown there may be an increase in the type 2 IL‐4 producing T‐cells whereas in non‐susceptible subjects, type 1 IL‐2/IFN‐γ producing T‐cells may preferentially home to the gingiva. This hypothesis is generally supported by recent data obtained from human studies but data obtained from animal studies is only partly supportive and may suggest the opposite. Nevertheless, it is now possible to construct a testable framework or model of CIPD based on these cellular and molecular mechanisms

Priming a sense of security: what goes through people’s minds?

There is a growing literature charting the positive personaland interpersonal effects of security priming. Security primesenhance self- and relationship views, and even evaluationsof outgroups, relative to control primes. We examine howsecurity priming is experienced by individuals and how itseffects differ from those produced by other positive affect andrelationship-related primes. We analyze the written protocolsproduced by individuals in different priming conditions forfrequency of felt security, care, merging, agency, communion,and nostalgia words. Security priming led to thoughts relatedto felt security, positive care, a sense of merging with another,positive emotion, and communion; furthermore, the effectsof security priming could be distinguished from the effects ofpositive affect and other relationship-related primes. We discussseveral directions for future research

Repeat bacterial challenge in a subcutaneous chamber model results in augmented tumour necrosis factor-α and interferon-γ response, and suppression of interleukin-10

The present study compared the effect of a single or a repeat challenge with the Gram-negative pathogen Porphyromonas gingivalis on the local inflammatory response within subcutaneous chamber model in mice. Subcutaneous chambers were implanted 2 weeks prior to the final challenge. The repeat-challenge (REP) group received two intrachamber bacterial injections 14 days apart, while the single-injection group (SIN) received only a single bacterial challenge. Injection of saline was used as the control. The cellular contents of the chamber exudates were used for differential cell counts, and the supernatants were analysed for tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and interleukin (IL)-10 levels. Immunoglobulin G1 (IgG1) and IgG2a levels to P. gingivalis in the exudates were also determined. The results showed that the leucocyte counts increased significantly post-challenge, and the REP group showed the highest number of lymphocytes and neutrophils. Both P. gingivalis-challenged groups exhibited significant increase in TNF-α and IL-10 levels at day 1 post-challenge. TNF-α levels in the chamber exudate were threefold higher in the REP group compared with the SIN group on day 1 post-challenge (P < 0·05). In contrast, IL-10 levels were significantly lower in the REP group 1 day post-challenge compared with the SIN group. The REP group had significantly higher levels of IFN-γ at baseline, and this difference remained significant 1 day post-challenge. Analysis of antibody levels to P. gingivalis showed that while the control and the SIN groups had no anti-P. gingivalis IgG in the chamber exudate during the 7-day study period, the REP group showed high anti-P. gingivalis IgG levels. In addition, the titres of IgG2a were fivefold higher than the IgG1 titres. The results showed that a repeat local challenge with P. gingivalis augmented the proinflammatory cytokines TNF-α and IFN-γ, while inhibiting the accumulation of the anti-inflammatory cytokine IL-10. This shift towards a T helper 1 (Th1)-dominant response was reflected in the relatively high anti-P. gingivalis IgG2a titres in the local inflammatory environment 7 days post-challenge