Elementary abelian subgroups in p-groups with a cyclic derived group

Let p be an arbitrary prime and let P be a finite p-group. The general objective of this paper is to obtain refined information on the homotopy type of the poset of all non-trivial elementary abelian subgroups of P, ordered by inclusion, and the poset of all elementary abelian subgroups of P of rank at least 2

Elementary abelian subgroups in p-groups of class 2

All the results in this work concern (finite) p-groups. Chapter 1 is concerned with classifications of some classes of p-groups of class 2 and there are no particularly new results in this chapter, which serves more as an introductory chapter. The "geometric" method we use for these classifications differs however from the standard approach, especially for p-groups of class 2 with cyclic center, and can be of some interest in this situation. This "geometry" will for instance, prove to be particularly useful for the description of the automorphism groups performed in Chapter 3. Our main results can be found in chapters 2 and Chapter 3. The results of Chapter 2 have a geometric flavour and concern the study of upper intervals in the poset Ap(P) for p-groups P. We already know from work of Bouc and Thévenaz [8], that Ap(P)≥2 is always homotopy equivalent to a wedge of spheres. The first main result in Section 2.4, is a sharp upper bound, depending only on the order of the group, to the dimension of the spheres occurring in Ap(P)≥2. More precisely, we show that if P has order pn, then H~k(Ap(P)≥2) = 0 if k ≥ ⎣n-1/2⎦. The second main result in this section is a characterization of the p-groups for which this bound is reached. The main results in Section 2.3 are numerical values for the number of the spheres occurring in Ap(P)≥2 and their dimension, when P is a p-group with a cyclic derived subgroup. Using these calculations, we determine precisely in Section 2.5, for which p-groups with a cyclic center, the poset Ap(P) is homotopically Cohen-Macaulay. Section 2.7 is an attempt to generalize the work of Bouc and Thévenaz [8]. The main result of this section is a spectral sequence E1rs converging to H~r+s(Ap(P)>Z), for any Z ∈ Ap(P). We show also that this spectral sequence can be used to recover Bouc and Thévenaz's results [8]. In Section 2.8, we give counterexamples to results of Fumagalli [12]. As an important consequence, Fumagalli's claim that Ap(G) is homotopy equivalent to a wedge of spheres, for solvable groups G, seems to remain an open question. The results of Chapter 3 are more algebraic and concern automorphism groups of p-groups. The main result is a description of Aut(P), when P is any group in one of the following two classes: p-groups with a cyclic Frattini subgroup. odd order p-groups of class 2 such that the quotient by the center is homocyclic

Social representations of mask wearing in the general population during the COVID-19 pandemic

IntroductionAlthough one of the most prominent interventions against COVID-19, face masks seem poorly adopted by the general population. A growing body of literature has found that using face masks has social meaning. This qualitative study assessed the perceptions, representations and practices of mask wearing in the general population.MethodsA qualitative survey by short semi-structured walking interviews was carried out from April to December 2021 in 11 cities in France's Pays de la Loire region. Study locations were selected for their varied geographical, social, and economic characteristics, with urbanized and rural areas. Four domains linked to perceptions of masks and wearing them were explored: (i) evolution in mask wearing, (ii) decision-making methods for wearing and not wearing; (iii) incorporating the mask into way of life; (iv) projecting into the future.ResultsA total of 116 people were interviewed. Masks marked a shift from the ordinary world to the pandemic. Overall, interviewees considered masks an obstacle to breathing, communication, and social interactions, leading to establishing strategies circumventing the mask mandate. Poor attention was paid to their medical usefulness as an obligatory clothing accessory. Mask-wearing decisions were driven by social relations, common sense, and vulnerability. The greater the feeling of security (i.e., being with close relatives), the less it was worn or worn properly, with decreased attention to others and their health. Most participants did not remember learning to wear a mask. Some were convinced that mask-wearing could not be learned (experiential knowledge). Institutions (school and work) played a central role by facilitating incorporation of masks into daily life.ConclusionsThis study emphasizes the need to reinforce the individual medical values of face masks to prevent COVID-19. Ambitious education and training programmes should be planned to learn how and when to wear masks. Institutions (work and school) may be critical for this purpose

Three cases of BRAF mutation negative Erdheim-Chester disease with a challenging distinction from IgG4-related disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans histiocytosis with slow progression over the years that is particularly difficult to diagnose

ABC des polypes coliques [Abecedary of colonic polyps]

Colonic polyps are very common in the general population. Some polyps present a cancerization risk and their screening and management by endoscopy reduce the risk of colorectal cancer. Other polyps do not need specific follow-up. There are different types of polyps whose classification has been updated over the last ten years. Serrated polyps now intersect hyperplastic polyps, sessile serrated adenomas and traditional serrated adenomas. Current recommendations are to resect and histologically analyze each colonic polyp to define a personalized endoscopic surveillance strategy. Some colonic polyposis syndromes require management in a specialized center

Tobacco Alkaloid Assessment in a DSS-Induced Colitis Mouse Model with a Fully Humanized Immune System

Inflammatory bowel disease (IBD) refers to chronic intestinal immune-mediated diseases including two main disease manifestations: ulcerative colitis (UC) and Crohn’s disease (CD). Epidemiological, clinical, and preclinical evidence has highlighted the potential anti-inflammatory properties of naturally occurring alkaloids. In the present study, we investigated the potential anti-inflammatory activities of the tobacco alkaloids nicotine and anatabine in a dextran sulfate sodium (DSS)-induced UC mouse model with a fully humanized immune system. Our results show that nicotine significantly reduced all acute colitis symptoms and improved colitis-specific endpoints, including histopathologically assessed colon inflammation, tissue damage, and mononuclear cell infiltration. The tobacco alkaloid anatabine showed similar effectiveness trends, although they were generally weaker or not significant. Gene expression analysis in the context of biological network models of IBD further pinpointed a possible mechanism by which nicotine attenuated DSS-induced colitis in humanized mice. The current study enables further investigation of possible molecular mechanisms by which tobacco alkaloids attenuate UC symptoms