The use of transverse connectors as reinforcement of multi-leaf walls

The need for new retrofitting techniques is the consequence of an increasing interest in the conservation of historic construction. The global behavior of a stone masonry structure is often governed by the level of connection between masonry wall leaves and the overall quality of the masonry material. This paper presents the results of an investigation carried out on site and in the laboratory on multi-leaf stone masonry panels strengthened using stainless steel rod inserted in a grouted fabric sleeve. The aim is to increase the collaboration between weakly connected masonry leaves. Pull-out tests were conducted on site on full-scale stone masonry wall panels, with the aim of studying the force required to pull out a connector under uniaxial tension. Several wall panels were assembled in the laboratory using solid calcareous stones and weak mortar and the effectiveness of the connectors was tested in shear and compression on both virgin and damaged panels. The experimental tests allowed the analysis of the behavior of the multi-leaf panels. Experimental results show that a substantial improvement of the wall panels' mechanical behavior can be achieved by applying transverse connectors

Repairing brickwork panels using titanium rods embedded in the mortar joints

This paper investigates repairing brickwork masonry walls using smooth titanium rods. Firstly, numerical analyses were carried out following a detailed micro-modelling strategy and then an experimental research program was undertaken in the laboratory. Solid clay brick specimens were initially tested, without strengthening, and subsequently re-tested, after repair, using titanium rods. Rods were embedded into the horizontal joints using an epoxy paste or a cement mortar. A double-sided repair was considered. Shear tests were carried out on four brickwork panels, under diagonal loading. The mechanism by which the diagonal shear load was carried was analyzed, varying from the uncracked state, to the final, cracked state, for both control and repaired wall panels. The results demonstrate that it is partially possible to restore the panels’ original in-plane shear capacity by embedding titanium rods into the horizontal bed joints using the epoxy paste. The experimental results were used to evaluate the effectiveness of the titanium repair, and recommendations are made to allow the test data to be used in the design procedure of cracked masonry structures. Unsatisfactory test results were recorded for panels repaired using a cement mortar

Low Expression of Programmed Death 1 (PD-1), PD-1 Ligand 1 (PD-L1), and Low CD8+ T Lymphocyte Infiltration Identify a Subgroup of Patients With Gastric and Esophageal Adenocarcinoma With Severe Prognosis

Prognosis of gastric and esophageal cancer is poor and treatment improvements are needed. Programmed cell death 1 receptor (PD-1) interaction with its ligand PD-L1 in tumor micro-environment promotes immune tolerance and blocking monoclonal antibodies have entered clinical practice. However, clinical significance of PD-1 and PD-L1 expression in gastric and esophageal adenocarcinomas, particularly in non-Asian patients, is still unclear. Three tissue microarrays including 190 clinically annotated esophageal (n = 31) and gastric (n = 159) adenocarcinomas and 58 paired mucosa specimens, were stained with PD-1, PD-L1, and CD8-specific reagents in indirect immunohistochemistry assays. PD-L1 expression was detectable in 23.2% of cancer specimens. High PD-1 expression was detectable in 37.3% of cases and high CD8+ infiltration in 76%. PD-L1 and high PD1 expression significantly correlated with each other (rs = 0.404, P < 0.0001) and both significantly correlated with CD8+ infiltration (rs = 0.435, P = 0.0003, and rs = 0.444; P = 0.0004, respectively). CD8+ lymphocyte infiltration correlated with improved survival in univariate (P = 0.009), but not multivariate analysis. Most interestingly, multivariate analysis and Kaplan-Meier curves indicate that combined low PD-1/PD-L1 expression and low CD8+ lymphocyte infiltration significantly correlate with poor prognosis. Our data document the clinical significance of a microenvironmental signature including PD-1/PD-L1 expression and CD8+ lymphocyte infiltration in gastric and esophageal adenocarcinomas and contribute to identify a patients' subset requiring more aggressive peri-operative treatments

High myeloperoxidase positive cell infiltration in colorectal cancer is an independent favorable prognostic factor

BACKGROUND Colorectal cancer (CRC) infiltration by adaptive immune system cells correlates with favorable prognosis. The role of the innate immune system is still debated. Here we addressed the prognostic impact of CRC infiltration by neutrophil granulocytes (NG). METHODS A TMA including healthy mucosa and clinically annotated CRC specimens (n = 1491) was stained with MPO and CD15 specific antibodies. MPO+ and CD15+ positive immune cells were counted by three independent observers. Phenotypic profiles of CRC infiltrating MPO+ and CD15+ cells were validated by flow cytometry on cell suspensions derived from enzymatically digested surgical specimens. Survival analysis was performed by splitting randomized data in training and validation subsets. RESULTS MPO+ and CD15+ cell infiltration were significantly correlated (p<0.0001; r = 0.76). However, only high density of MPO+ cell infiltration was associated with significantly improved survival in training (P = 0.038) and validation (P = 0.002) sets. In multivariate analysis including T and N stage, vascular invasion, tumor border configuration and microsatellite instability status, MPO+ cell infiltration proved an independent prognostic marker overall (P = 0.004; HR = 0.65; CI:±0.15) and in both training (P = 0.048) and validation (P = 0.036) sets. Flow-cytometry analysis of CRC cell suspensions derived from clinical specimens showed that while MPO+ cells were largely CD15+/CD66b+, sizeable percentages of CD15+ and CD66b+ cells were MPO-. CONCLUSIONS High density MPO+ cell infiltration is a novel independent favorable prognostic factor in CRC

Masonry Columns Confined by Steel Fiber Composite Wraps

The application of steel fiber reinforced polymer (SRP) as a means of increasing the capacity of masonry columns is investigated in this study. The behavior of 23 solid-brick specimens that are externally wrapped by SRP sheets in low volumetric ratios is presented. The specimens are subjected to axial monotonic load until failure occurs. Two widely used types of masonry columns of differing square cross-sections were tested in compression (square and octagonal cross-sections). It is concluded that SRP-confined masonry behaves very much like fiber reinforced polymers (FRP)-confined masonry. Confinement increases both the load-carrying capacity and the deformability of masonry almost linearly with average confining stress. A comparative analysis between experimental and theoretical values computed in compliance with the Italian Council of Research (CNR) was also developed

Experimental analysis of dynamic effects of FRP reinforced masonry vaults

An increasing interest in the preservation of historic structures has produced a need for new methods for reinforcing curved masonry structures, such as arches and vaults. These structures are generally very ancient, have geometries and materials which are poorly defined and have been exposed to long-term historical movements and actions. Consequently, they are often in need of repair or reinforcement. This article presents the results of an experimental study carried out in the laboratory and during on-site testing to investigate the behaviour of brick masonry vaults under dynamic loading strengthened with FRPs (Fiber Reinforced Polymers). For the laboratory tests, the brick vaults were built with solid sanded clay bricks and weak mortar and were tested under dynamic loading. The experimental tests were designed to facilitate analysis of the dynamic behaviour of undamaged, damaged and reinforced vaulted structures. On-site tests were carried out on an earthquake-damaged thin brick vault of an 18th century aristocratic residence in the city of L’Aquila, Italy. The provision of FRP reinforcement is shown to re-establish elastic behavior previously compromised by time induced damage in the vaults

Shear strengthening of wall panels through jacketing with cement mortar reinforced by GFRP grids

This paper gives the results of a series of shear tests carried out on historic wall panels reinforced with an innovative technique by means of jacketing with GFRP (Glass Fiber Reinforced Plastics) mesh inserted into an inorganic matrix. Tests were carried out in situ on panels cut from three different historic buildings in Italy: two in double-leaf rough hewn rubble stone masonry in Umbria and L'Aquila and another with solid brick masonry in Emilia. Two widely-known test methods: the diagonal compression test and the shear-compression test with existing confinement stress. The test results enabled the determination of the shear strength of the masonry before and after the application of the reinforcement. The panels strengthened with the GFRP exhibited a significant improvement in lateral load-carrying capacity of up to 1060% when compared to the control panels. A numerical study assessed the global behavior and the stress evolution in the unreinforced and strengthened panels using a finite element code