No Self-Interaction for Two-Column Massless Fields

We investigate the problem of introducing consistent self-couplings in free theories for mixed tensor gauge fields whose symmetry properties are characterized by Young diagrams made of two columns of arbitrary (but different) lengths. We prove that, in flat space, these theories admit no local, Poincar\'e-invariant, smooth, self-interacting deformation with at most two derivatives in the Lagrangian. Relaxing the derivative and Lorentz-invariance assumptions, there still is no deformation that modifies the gauge algebra, and in most cases no deformation that alters the gauge transformations.Our approach is based on a BRST-cohomology deformation procedure.Comment: 41 pages, LaTe

A note on spin-s duality

Duality is investigated for higher spin ($s \geq 2$), free, massless, bosonic gauge fields. We show how the dual formulations can be derived from a common "parent", first-order action. This goes beyond most of the previous treatments where higher-spin duality was investigated at the level of the equations of motion only. In D=4 spacetime dimensions, the dual theories turn out to be described by the same Pauli-Fierz (s=2) or Fronsdal ($s \geq 3$) action (as it is the case for spin 1). In the particular s=2 D=5 case, the Pauli-Fierz action and the Curtright action are shown to be related through duality. A crucial ingredient of the analysis is given by the first-order, gauge-like, reformulation of higher spin theories due to Vasiliev.Comment: Minor corrections, reference adde

Spin three gauge theory revisited

We study the problem of consistent interactions for spin-3 gauge fields in flat spacetime of arbitrary dimension n>3. Under the sole assumptions of Poincar\'e and parity invariance, local and perturbative deformation of the free theory, we determine all nontrivial consistent deformations of the abelian gauge algebra and classify the corresponding deformations of the quadratic action, at first order in the deformation parameter. We prove that all such vertices are cubic, contain a total of either three or five derivatives and are uniquely characterized by a rank-three constant tensor (an internal algebra structure constant). The covariant cubic vertex containing three derivatives is the vertex discovered by Berends, Burgers and van Dam, which however leads to inconsistencies at second order in the deformation parameter. In dimensions n>4 and for a completely antisymmetric structure constant tensor, another covariant cubic vertex exists, which contains five derivatives and passes the consistency test where the previous vertex failed.Comment: LaTeX, 37 pages. References and comments added. Published versio

Asthma-related inflammation promotes lung metastasis of breast cancer cells through CCL11–CCR3 pathway

Background: Mechanisms that preclude lung metastasis are still barely understood. The possible consequences of allergic airways inflammation on cancer dissemination were studied in a mouse model of breast cancer. Methods: Balb/c mice were immunized and daily exposed to ovalbumin (OVA) from day 21. They were subcutane- ously injected with 4T1 mammary tumor cells on day 45 and sacrificed on day 67. Lung metastases were measured by biophotonic imaging (IVIS 200 Imaging System) and histological measurement of tumor area (Cytomine software). Effects of CCL11 were assessed in vivo by intratracheal instillations of recCCL11 and in vitro using Boyden chambers. CCR3 expression on cell surface was assessed by flow cytometry. Results: The extent of tumor metastases was significantly higher in lungs of OVA-exposed mice and increased levels of CCL11 expression were measured after OVA exposure. Migration of 4T1 cells and neutrophils was stimulated in vitro and in vivo by recCCL11. 4T1 cells and neutrophils express CCR3 as shown by flow cytometry and a selective CCR3 antagonist (SB-297006) inhibited the induction of 4T1 cells migration and proliferation in response to recCCL11. Conclusions: Allergic inflammation generated by exposure to allergens triggers the implantation of metastatic cells from primary breast tumor into lung tissues plausibly in a CCL11–CCR3-dependent manner. This indicates that asthma related inflammation in lungs might be a risk factor for lung metastasis in breast cancer patients.Peer reviewe

Worn Dentition No Prep Treatment with PICN restorations: 4-yr results

To prospectively evaluate the 4-yr results of the One-step No-prep treatment of full mouth-worn dentition, a minimally invasive and multidisciplinary approach using PICN CAD CAM composite restorations without provisional phas

Prolonged ex vivo culture of human bone marrow mesenchymal stem cells influences their supportive activity toward NOD/SCID -repopulating cells and committed progenitor cells of B lymphoid and myeloid lineages

Background Bone marrow (BM) mesenchymal stem cells (MSC) support proliferation and differentiation of hematopoietic progenitor cells (HPC) in vitro. Since they represent a rare subset of BM cells, MSC preparations for clinical purposes involves a preparative step of ex vivo multiplication. The aim of our study was to analyze the influence of culture duration on MSC supportive activity. DESIGN AND METHODS: MSC were expanded for up to 10 passages. MSC and CD34(+) cells were seeded in cytokine-free co-cultures after which the phenotype, clonogenic capacity and in vivo repopulating activity of harvested hematopoietic cells were assessed. RESULTS: Early passage MSC supported HPC expansion and differentiation toward both B lymphoid and myeloid lineages. Late passage MSC did not support HPC and myeloid cell outgrowth but maintained B cell supportive ability. In vitro maintenance of NOD/SCID mouse repopulating cells cultured for one week in contact with MSC was effective until the fourth MSC passage and declined afterwards. CD34(+) cells achieved higher levels of engraftment in NOD/SCID mice when co-injected with early passage MSC; however MSC expanded beyond 9 passages were ineffective in promoting CD34(+) cell engraftment. Non-contact cultures indicated that MSC supportive activity involved diffusible factors. Among these, interleukin (IL)-6 and IL-8 contributed to the supportive activity of early passage MSC but not of late passage MSC. MSC phenotype as well as fat, bone and cartilage differentiation capacity did not change during MSC culture. Conclusions Extended MSC culture alters their supportive ability toward HPC without concomitant changes in phenotype and differentiation capacity

One tooth-One time (1T1T), immediate loading of posterior single implants with the final crown: Two-year results of a case series.

AIMS: The aim of this study was to evaluate the two-year outcomes of the One Tooth-One Time (1T1T) completely digital workflow, allowing the immediate loading of a single implant in the posterior region with a final CAD-CAM crown made of a polymer-infiltrated ceramic network (PICN). MATERIALS AND METHODS: A series of 10 implants were placed, and an intra-oral scan was taken after the surgery. A final screw-retained PICN crown was manufactured chair-side and placed the same day in full occlusion. Marginal peri-implant bone changes and soft-tissue health were evaluated, as well as restoration performance using World Dental Federation criteria and Pink and White Esthetic Scores. Patient-related outcome measures (PROMs) and time consumption data were collected. RESULTS: After two years, the implant survival rate was 100%. The debonding of one crown from its Titanium Base led to a 90% prosthodontic survival rate and the remaining crowns were all considered successful. The mean marginal peri-implant bone changes yielded 0.87 (SD: 0.96) and 0.55 (SD: 0.53) mm after one and two years, respectively. Mild or no inflammation of peri-implant soft tissue was observed in most implants. The overall treatment time reached 175 min and PROMs displayed high patient satisfaction. CONCLUSIONS: This study constitutes the first report considering immediate loading of a single implant in the posterior region with a final crown in occlusion. In this case-series, the two-year outcomes of the 1T1T protocol seem rather promising and fulfil patient expectations. However, those preliminary results need to be confirmed by randomized control trials and patient selection is probably a key factor in this procedure success

Bonding properties of third generation zirconia materials

To use the Notchless Triangular Prism (NTP) test to compare the Interfacial Fracture Toughness (IFT) of 2 resin cements, Panavia-SA Cement Plus (SA) and Panavia-V5 + Ceramic Primer (V5) (Kuraray Noritake), and a resin-modified glass-ionomer cement (RMGIC) Fuji-Plus (GC Corporation), with Katana zirconia CAD-CAM blocks of the third generation (Kuraray Noritake) for CEREC systems, after sandblasting with 50-µm Al2O3 particles at 0.5-bar and 2.5-bars and upon thermocycling aging

PROPRIÉTÉS DE LIAISON DES MATÉRIAUX EN ZIRCONE DE TROISIÈME GÉNÉRATION

peer reviewedIl existe peu de données à l’heure actuelle concernant les zircones de troisième génération, qui contiennent 4 à 5% molaire d’oxyde d’yttrium pour augmenter la translucidité du matériau1. Bien que moins résistantes mécaniquement que les deux générations précédentes, ces zircones permettent de réaliser des restaurations monolithiques unitaires, notamment des restaurations collées de type facettes. Elles existent notamment sous forme de blocs destinés à être usinés et frittés au cabinet dentaire. L’objectif de cette étude est d’évaluer la ténacité interfaciale (IFT) entre une zircone de troisième génération pour CFAO directe (Cerec Katana Zirconia, Kuraray Noritake) et deux types de colles, le Panavia-SA Cement Plus (SA) et le Panavia-V5+Ceramic primer (V5) (Kuraray Noritake), ainsi qu’un ciment verre ionomère modifié par addition de résine (RMGIC) (Fuji-Plus, GC Corporation)