SARS-CoV-2 Breakthrough Infections: Incidence and Risk Factors in a Large European Multicentric Cohort of Health Workers.

Background: The research aimed to investigate the incidence of SARS-CoV-2 breakthrough infections and their determinants in a large European cohort of more than 60,000 health workers. Methods: A multicentric retrospective cohort study, involving 12 European centers, was carried out within the ORCHESTRA project, collecting data up to 18 November 2021 on fully vaccinated health workers. The cumulative incidence of SARS-CoV-2 breakthrough infections was investigated with its association with occupational and social-demographic characteristics (age, sex, job title, previous SARS-CoV-2 infection, antibody titer levels, and time from the vaccination course completion). Results: Among 64,172 health workers from 12 European health centers, 797 breakthrough infections were observed (cumulative incidence of 1.2%). The primary analysis using individual data on 8 out of 12 centers showed that age and previous infection significantly modified breakthrough infection rates. In the meta-analysis of aggregated data from all centers, previous SARS-CoV-2 infection and the standardized antibody titer were inversely related to the risk of breakthrough infection (p = 0.008 and p = 0.007, respectively). Conclusion: The inverse correlation of antibody titer with the risk of breakthrough infection supports the evidence that vaccination plays a primary role in infection prevention, especially in health workers. Cellular immunity, previous clinical conditions, and vaccination timing should be further investigated

The mediating effects of family dynamics and parent-adolescent sex communication on sexual risk taking behavior among adolescents

The purpose of this study was to analyze the relationships between family dynamics, parent-adolescent sex communication, adolescent sexual risk behaviors, and rates of adolescent STIs and pregnancy. Correlations, t-tests, and logistic regressions were used to analyze the relationships between all variables. The results supported the hypothesis that family dynamics influences parent-adolescent sex communication. Results also supported the hypotheses that sex communication influences adolescent sexual risk behaviors, as well as rates of adolescent pregnancy. Surprisingly, parent-adolescent sex communication did not significantly correlate with rates of STI diagnoses. As hypothesized, adolescent sexual risk behavior influenced rates of STIs and pregnancy among adolescents. Logistic regression analysis indicated that age, family cohesion, shared activities, parent bonding, parent absence, parent attitudes about adolescent sexual behavior, and adolescent religiosity significantly predict sexual risk behaviors, whereas parent-adolescent communication, parent-adolescent sex communication, and parent religiosity predicted less sexual risk behaviors. This study has important implications for parents, clinicians, and educators who work with adolescents engaging in sexual activity

Classification of regular embeddings of hypercubes of odd dimension

By a regular embedding of a graph into a closed surface we mean a 2-cell embedding with the automorphism group acting regularly on flags. Recently, Kwon and Nedela [Non-existence of nonorientable regular embeddings of n-dimensional cubes, Discrete Math., to appear] showed that no regular embeddings of the n-dimensional cubes Q, into nonorientable surfaces exist for any positive integer n > 2. In 1997, Nedela and Skoviera [Regular maps from voltage assignments and exponent groups, European J. Combin. 18 (1997) 807-823] presented a construction giving for each solution of the congrumce e(2) equivalent to 1 (mod n) a regular embedding M-e of the hypercube Q(n) into an orientable surface. It was conjectured that all regular embeddings of Q(n) into orientable surfaces can be constructed in this way. This paper gives a classification of regular embeddings of hypercubes Q(n) into orientable surfaces for n odd, proving affirmatively the conjecture of Nedela and koviera for every odd n. (c) 2006 Elsevier B.V. All rights reserved.X1113sciescopu

Regular embeddings of complete multipartite graphs

In this paper, we classify all regular embeddings of the complete multipartite graphs K (p,..., p) a prime p into orientable surfaces. Also, the same work is done for the regular embeddings of the lexicographical product of any connected arc-transitive graph of prime order q with the complement of the complete graph of prime order p, where q and p are not necessarily distinct. Lots of regular maps found in this paper are Cayley maps. (C) 2004 Elsevier Ltd. All rights reserved.X1120sciescopu

REGULAR EMBEDDINGS OF K-N,K-N WHERE N IS A POWER OF 2. I: METACYCLIC CASE

A 2-cell embedding of a graph in an orientable closed surface is called regular if its automorphism group acts regularly on arcs of the embedded graph. The aim of this and of the associated consecutive paper is to give a classification of regular embeddings of complete bipartite graphs K-n.n, where n = 2(e). The method involves groups G which factorize as a product XY of two cyclic groups of order n so that the two cyclic factors are transposed by an involutory automorphism. In particular, we give a classification of such groups G. Employing the classification we investigate automorphisms of these groups, resulting in a classification of regular embeddings of K-n.n, based on that for G. We prove that given n = 2(e) (for e >= 3), there are, up to map isomorphism, exactly 2(e-2) + 4 regular embeddings of K-n.n. Our analysis splits naturally into two cases depending on whether the group G is metacyclic or not. (C) 2006 Elsevier Ltd. All rights reserved.X1124sciescopu

Ripple polystyrene nano-pattern induced by KrF laser

The study of excimer laser treatment of polystyrene surface was performed. The influence of laser fluence and number of laser pulses on surface chemistry and morphology was determined. The surface morphology and roughness were studied with atomic force microscopy. Surface wettability and aging studies were characterized by the water contact angle measurements. Surface oxygen concentration and chemistry were evaluated from X-ray photoelectron spectroscopy and zeta potential measurements. The optimal polystyrene treatment parameters for the most regular pattern were determined. The foils with optimal ripple pattern were subsequently sputtered with gold nano-layers of 100 nm thickness. It was found that the surface roughness of PS strongly depends on number of pulses. The aging study revealed that the higher contact angle achieve the samples treated with higher laser fluence. The deposition of gold nano-layer increases the surface roughness of nano-patterned surface. It was proved that the oxygen concentration is significantly influenced by the KrF laser exposure