A two-dimensional deconvolution stability conditions

Deconvolution is the main prohlems of images restoration . This study deals with phenomena due to deconvolution, so stability conditions are precised about center cross convolution mask with Huang's theorem .La déconvolution est au centre des problèmes de reconstruction d'images. Dans cet article, nous présentons les phénomènes engendrés par cette opération. Nous définissons les conditions de stabilité des masques de convolution de type centré avec un voisinage en croix à partir du théorême de Huan

A 2022 τ\tau-Herculid meteor cluster from an airborne experiment: automated detection, characterization, and consequences for meteoroids

Context. The existence of meteor clusters has long since been a subject of speculation and so far only seven events have been reported, among which two involve less than five meteors, and three were seen during the Leonid storms. Aims. The 1995 outburst of Comet 73P/Schwassmann-Wachmann was predicted to result in a meteor shower in May 2022. We detected the shower, proved this to be the result of this outburst, and detected another meteor cluster during the same observation mission. Methods. The {\tau}-Herculids meteor shower outburst on 31 May 2022 was continuously monitored for 4 hours during an airborne campaign. The video data were analyzed using a recently developed computer-vision processing chain for meteor real-time detection. Results. We report and characterize the detection of a meteor cluster involving 38 fragments, detected at 06:48 UT for a total duration of 11.3 s. The derived cumulative size frequency distribution index is relatively shallow: s = 3.1. Our open-source computer-vision processing chain (named FMDT) detects 100% of the meteors that a human eye is able to detect in the video. Classical automated motion detection assuming a static camera was not suitable for the stabilized camera setup because of residual motion. Conclusions. From all reported meteor clusters, we crudely estimate their occurrence to be less than one per million observed meteors. Low heliocentric distance enhances the probability of such meteoroid self-disruption in the interplanetary space.Comment: 6 pqges, 5 figure

Activation of natural regulatory T cells by IgG Fc-derived peptide Tregitopes

We have identified at least 2 highly promiscuous major histocompatibility complex class II T-cell epitopes in the Fc fragment of IgG that are capable of specifically activating CD4+CD25HiFoxP3+ natural regulatory T cells (nTRegs). Coincubation of these regulatory T-cell epitopes or “Tregitopes” and antigens with peripheral blood mononuclear cells led to a suppression of effector cytokine secretion, reduced proliferation of effector T cells, and caused an increase in cell surface markers associated with TRegs such as FoxP3. In vivo administration of the murine homologue of the Fc region Tregitope resulted in suppression of immune response to a known immunogen. These data suggest that one mechanism for the immunosuppressive activity of IgG, such as with IVIG, may be related to the activity of regulatory T cells. In this model, regulatory T-cell epitopes in IgG activate a subset of nTRegs that tips the resulting immune response toward tolerance rather than immunogenicity

Immune Cell Recruitment and Cell-Based System for Cancer Therapy

Immune cells, such as cytotoxic T lymphocytes, natural killer cells, B cells, and dendritic cells, have a central role in cancer immunotherapy. Conventional studies of cancer immunotherapy have focused mainly on the search for an efficient means to prime/activate tumor-associated antigen-specific immunity. A systematic understanding of the molecular basis of the trafficking and biodistribution of immune cells, however, is important for the development of more efficacious cancer immunotherapies. It is well established that the basis and premise of immunotherapy is the accumulation of effective immune cells in tumor tissues. Therefore, it is crucial to control the distribution of immune cells to optimize cancer immunotherapy. Recent characterization of various chemokines and chemokine receptors in the immune system has increased our knowledge of the regulatory mechanisms of the immune response and tolerance based on immune cell localization. Here, we review the immune cell recruitment and cell-based systems that can potentially control the systemic pharmacokinetics of immune cells and, in particular, focus on cell migrating molecules, i.e., chemokines, and their receptors, and their use in cancer immunotherapy

Dependence of T Cell Antigen Recognition on the Dimensions of an Accessory Receptor–Ligand Complex

The T cell antigen receptor (TCR) and its ligand peptide–major histocompatibility complex (MHC) are small (∼7 nm) compared with other abundant cell surface molecules such as integrins, CD43, and CD45 (23–50 nm). We have proposed that molecules at the T cell/antigen-presenting cell (APC) interface segregate according to size, with small “accessory” molecules (e.g., CD2, CD4, CD8, CD28, and CD154) contributing to the formation of a close-contact zone, within which the TCR engages peptide–MHC, and from which large molecules are excluded (Davis, S.J., and P.A. van der Merwe. 1996. Immunol. Today. 17:177–187). One prediction of this model is that increasing the size of these small accessory molecules will disrupt their function. Here, we test this prediction by varying the dimensions of the CD2 ligand, CD48, and examining how this affects T cell antigen recognition. Although the interaction of CD2 on T cells with wild-type or shortened forms of CD48 on APCs enhances T cell antigen recognition, the interaction of CD2 with elongated forms of CD48 is strongly inhibitory. Further experiments indicated that elongation of the CD2/CD48 complex inhibited TCR engagement of peptide–MHC, presumably by preventing the formation of sufficiently intimate contacts at the T cell/APC interface. These findings demonstrate the importance of small size in CD2/CD48 function, and support the hypothesis that T cell antigen recognition requires segregation of cell surface molecules according to size

Organizational and corporate identity revisited: Towards a comprehensive understanding of identity in business

ABSTRACT: Purpose – This paper provides a comprehensive and integrative review of academic literature analyzing identity in business. The literature review proposed by the authors helps clearing up theoretical and practical understanding of this concept. Design/methodology/approach – A review of existing literature in organizational behavior and marketing fields is proposed to clarify the meaning of organizational and corporate identity. On the basis of this review, the authors also identify an integrative perspective proposed for managers to identify and effectively manage all dimensions of their business identities. Findings – Literature on the identity of businesses is extensive and blurred, failing to provide useful guidance for practitioners to manage this concept. A new approach proposes understanding this kind of identity as a global concept that integrates proposals from diverse research fields in order to take advantage of cross-fertilization. Practical implications – This research allows identity and communication managers to understand dimensions of business identity for a more effective management of this concept in their organizations. Originality/value – The line of research that proposes an integrative multidisciplinary approach to the study of identity in business is quite new and, as so, it still needs further contributions to clarify this nascent domain. In this paper, the authors also classify previous studies on business identity according to the theoretical approach they assume just as no other research has done before. Borra