Bubble-resummation and critical-point methods for β\beta-functions at large NN

We investigate the connection between the bubble-resummation and critical-point methods for computing the $\beta$-functions in the limit of large number of flavours, $N$, and show that these can provide complementary information. While the methods are equivalent for single-coupling theories, for multi-coupling case the standard critical exponents are only sensitive to a combination of the independent pieces entering the $\beta$-functions, so that additional input or direct computation are needed to decipher this missing information. In particular, we evaluate the $\beta$-function for the quartic coupling in the Gross-Neveu-Yukawa model, thereby completing the full system at $\mathcal{O}(1/N)$. The corresponding critical exponents would imply a shrinking radius of convergence when $\mathcal{O}(1/N^2)$ terms are included, but our present result shows that the new singularity is actually present already at $\mathcal{O}(1/N)$, when the full system of $\beta$-functions is known.Comment: 11 pages, 7 figures; v2: references added, matches the published versio

Duality and Dimensional Reduction of 5D BF Theory

A planar boundary introduced \`a la Symanzik in the 5D topological BF theory, with the only requirement of locality and power counting, allows to uniquely determine a gauge invariant, non topological 4D Lagrangian. The boundary condition on the bulk fields is interpreted as a duality relation for the boundary fields, in analogy with the fermionization duality which holds in the 3D case. This suggests that the 4D degrees of freedom might be fermionic, although starting from a bosonic bulk theory. The method we propose to dimensionally reduce a Quantum Field Theory and to identify the resulting degrees of freedom can be applied to a generic spacetime dimension.Comment: 13 pages, plain LaTeX, version to appear on EPJ

Exaptive innovation in constraint-based environments: lessons from COVID-19 crisis

Purpose – This paper explores how exaptive innovation process might be considered a useful innovation model in constraint-based environments. Through an in-depth case study, it illustrates clearly the antecedents of exaptation processes, which are particularly relevant in rapidly changing environments requiring new solutions under time and resource constraints. Design/methodology/approach – The authors adopt a single case study approach that is particularly suitable in case of an inductive research design, which is required because of the novelty of the topic. The research is inspired by the use of the snorkeling mask EASYBREATH, commercialized by the giant Decathlon, as a medical device, a respirator to treat patients affected by coronavirus in Italy. The authors organized the evidence according to a novel taxonomy grounded in the literature. Findings – The case study stimulates reflections on the existence of some antecedents to the exaptive innovation process in constraint-based environments: (1) the availability of specific actors in the innovation process; (2) the creation of platforms of interaction between people with different competences, nurtured by collective bottom-up financing systems; (3) the role of the community of makers, in particular, and of the 4th industrial revolution, in general, for creating enabling technologies; (4) multidisciplinary individual background of key actors in the innovation process is crucial to ensure the exaptive path to be in place. Research limitations/implications – This work has some limitations, due to the choice of limiting the analysis to a single case, nevertheless, it offers a first glance on a new technological trajectory available in constraint-based environments. Originality/value – The case study results underline the importance of new digital collaboration platforms as knowledge multipliers, and illuminate on the potential of the fourth manufacturing revolution, which, through new technologies, creates opportunities for distributed forms of innovation that cross long distances

Gauging fractons and linearized gravity

We consider the covariant gauge field theory of fractons, which describe a new type of quasiparticles exhibiting novel and nontrivial properties. In particular, we focus on the field theoretical peculiarities which characterize this theory, starting from the fact that, if we accept the paradigm that quantum field theories are defined by their symmetries, fractons unavoidably come together with linearized gravity. The standard Faddeev-Popov procedure to gauge fix the theory leads to a scalar gauge condition, which has two important drawbacks: it is frozen in the Landau gauge and linearized gravity cannot be obtained as a limit. In this paper we adopt a tensorially alternative gauge fixing, which avoids both problems. In particular, this allows to show that important physical features, like the counting of the degrees of freedom, do not depend on a particular gauge choice, as expected. Moreover, the resulting gauge fixed theory contains both fractons and linearized gravity as a limit, differently from the standard scalar choice.Comment: 22 page

Reduction of Bacterial Proliferation by Zirconium Collar in Dental Implants

The peri-implant bacterial colonization is one of the current major problems facing dental implants with no actual protocols for prevention. The use of zirconium for bacterial eradication has already been reported and discussed in the dental literature. In this study we evaluated for the first time the ability of a "hybrid" dental implant model \u2013 where the implant collar is made out of titanium and zirconium - to reduce the peri-implant bacterial colonization, using traditional implants from the same manufacturer as controls. The results of microbiological analysis and the evaluation of the classic parameters of an implant success confirmed that, in all the 30 patients in this study, the zirconium collar had a vital role in reducing peri-implant bacterial colonization, and that the "hybrid" implants show lower plaque index values, less bleeding and less marginal bone loss than the traditional implants. Our data therefore suggest that a zirconium collar can effectively reduce the bacterial colonization around a titanium implant favoring a better long-term prognosis

Penetration of Sodium Hypochlorite Modified with Surfactants into Root Canal Dentin

Abstract The aim of this study was to evaluate the effect of concentration, exposure time and temperature of sodium hypochlorite (NaOCl) added with surfactants on its penetration into dentinal tubules. Sixty-five extracted human permanent maxillary anterior teeth with single canals were prepared by ProTaper SX hand-operated instruments. The teeth were then sectioned perpendicular to the long axis. The crowns and apical thirds of all the teeth were removed. The remaining roots were processed into 4-mm-long blocks and stained overnight in crystal violet. One hundred and thirty stained blocks were further split into halves and treated by nine different types of NaOCl-based solutions. Three solutions were added with surfactants (Hypoclean, H6, Chlor-Xtra) and the others were regular hypochlorites at increasing concentrations (1%, 2%, 4%, 5.25%, <6%, 6% NaOCl) from different brands. The dentin blocks were exposed to the solutions for 2, 5, and 20 min at 20 °C, 37 °C and 45 °C, respectively. The depth of NaOCl penetration was determined by bleaching of the stain and measured by light microscopy at 20 and 40. Statistical comparisons were made by using a generalized linear model with Bonferroni's post-hoc correction. The shortest penetration (81±6.6 μm) was obtained after incubation in 1% NaOCl for 2 min at 20 °C; the highest penetration (376.3±3.8 μm) was obtained with Chlor-Xtra for 20 min at 45 °C. Varying NaOCl concentration produced a minimal effect while temperature and exposure time had a significant direct relationship with NaOCl penetration into dentinal tubules, especially those with lowered surface tension. The exposure time and temperature of sodium hypochlorite as well as the addition of surfactants may influence the penetration depth of irrigants into dentinal tubules

In vitro and ex vivo studies on the antibacterial efficacy of sodium hypochlorite and two new generation endodontic irrigants, Tetraclean® and MTAD, in comparison with sodium hypochlorite.

The aim of this work was to compare the efficacy of two endodontic iorrigants of new generation, Tetraclean and MTAD. Their antimicrobial effectiveness was assessed by in vitro and in vivo studies. Sodium hypochlorite was included as standard reference irrigant

Clinical characterization of gingival type of burning mouth syndrome:a cross-sectional study

The aim of this study is to investigate the prevalence of localized intraoral neuropathic pain in a cluster of patients who reported the involvement of gingival site as only clinical manifestation of dysesthesia, analysing type and distribution of symptoms. Burning mouth syndrome (BMS) patients were enrolled in the study. Patients were screened through laboratory test and a conventional oral examination with periodontal chart. A questionnaire to collect data on symptoms, oral site involved, quality of sleep, anxiety was submitted to all the patients. A total of 236 patients were recruited. Seventy-six patients (32.2%) presented generalized type, whereas 160 (67.8%) had localized type. In the localized BMS group, the gingiva was involved in 70 patients and in 33 of these it was the only site involved. In the gingival subgroup, 35 patients reported burning, 29 pain and 24 xerostomia. To best our knowledge, this study is the first that analyses gingival involvement as the only site in BMS and it could encourage further investigations to understand the etiopathogenesis of gingival BMS

Compounds released from Lactobacillus (L.) acidophilus, L. plantarum, L. rhamnosus and L. reuteri inhibit Candida parapsilosis pathogenic potential after infection of vaginal epithelial cells in vitro.

INTRODUCTION. Lactobacillus spp. are the most represented microorganisms in the vaginal microbiota of healthy women, where they provide a shelter against infections from several pathogens, such as the yeasts belonging to the genus Candida. The latter are responsible for the vulvovaginal candidiasis (VVC), a condition affecting up to 75% of women during their child-bearing age at least once in their lifetime. Moreover, 5-8% of such women develop the recurrent form of the disease (RVVC), consisting of at least 5 VVC episodes per year. Notwithstanding C. albicans is the main responsible of VVC cases, in the last decades, the incidence of VVC cases by non-albicans Candida (NAC) species has become prevalent, especially in some geographical areas. C. parapsilosis, in particular, has been reported to be second species most commonly isolated from women affected by VVC. However, little is known on this species, and on its role in the pathogenesis of VVC. MATERIALS AND METHODS. Cell-free supernatants (CFS) were obtained following an overnight culture of 4 different Lactobacilli species (L. acidophilus, L. plantarum, L. rhamnosus, L. reuteri). Lactobacilli-released compounds, contained in CFS, were assessed for their effect on several virulence factors of C. parapsilosis (strain CLIB214), such as growth rate, capacity to form pseudohyphae, capacity to adhere to a vaginal epithelium in vitro (A-431 cells monolayer) and to induce cell damage. The latter was evaluated by measuring lactate dehydrogenase (LDH) release from A431 cells. RESULTS. C. parapsilosis growth inhibition by L. acidophilus, L. plantarum and L. reuteri CFS was 47%, 55% and 52% respectively, whereas L. rhamnosus CFS effect was weaker (33% inhibition growth). All the Lactobacilli significantly inhibited C. parapsilosis adhesion to vaginal epithelial cells: upon incubation with CFS, only 5-7% of fungal cells adhered to epithelial cells, after 90 minutes incubation; differently, the adhesion of the control reached 19%. Interestingly, no effect on pseudohyphae formation by any of the CSF was ever observed. Finally, the C. parapsilosis-induced damage on A-431 cells was significantly reduced by the addition of the CSF. DISCUSSION AND CONCLUSIONS. Our results show that the investigated species of Lactobacilli release compounds capable to impair several C. parapsilosis virulence factors, such as growth rate and adhesion to vaginal epithelial cells; interestingly, while not affecting fungal capacity to form pseudohyphae, such compounds significantly reduce Candida-mediated epithelial damage.. These data suggest that, in the context of vaginal microbiota, these Lactobacilli species may play an important role in counteracting the onset of mucosal Candida infections