Effects of plasma treatments of polypropylene adhesive joints used in the automotive industry

Plasma treatment has been used in recent years to activate the surfaces of adhesive substrates and thus as an adhesion promoter between adhesive and substrates. The use of plasma treatments is widely adopted in the automotive industries especially for polymers that present low surface energy, such as polypropylene. In this work, polypropylene substrates used in the automotive industries have been treated with two different techniques: vacuum and atmospheric plasma. Then, polyurethane and methacrylate adhesives have been used to bond single lap joints (SLJs). Typically, these two adhesives cannot bond polypropylene substrates without surface treatments. An experimental plan has been designed to investigate the process parameters that can increase the functional polar groups (FPGs) maximizing the adhesion strength. Besides the types of plasma, two different gas carriers (air and nitrogen) and different treatment times have been investigated. The substrates, treated and not treated, have been assessed through scanning electron microscopy, energy-dispersive X-ray analysis, and Fourier-transform infrared spectroscopy to quantitatively assess the increment of FPGs after the different treatments. The experimental plan shows that the atmospheric plasma can improve the surface of the substrates by using a smaller time. Mechanical tests on SLJs show that methacrylate and polyurethane cannot bond polypropylene substrates without the plasma treatment. On the other hand, the treated substrates can form a strong bonding with the adhesive since all SLJs exhibit a substrate failure. Mechanical tests have been also carried out after three different aging cycles showing that the adopted plasma treatment is not affected by the aging cycles

Epoxy and Bio-Based Epoxy Carbon Fiber Twill Composites: Comparison of the Quasi-Static Properties

In recent years, interest in sustainability has significantly increased in many industrial sectors. Sustainability can be achieved with both lightweight design and eco-friendly manufacturing processes. For example, concerns on the use of thermoset composite materials, with a lightweight design and a high specific strength, have arisen, since thermoset resins are not fully recyclable and are mainly petrol based. A possible solution to this issue is the replacement of the thermoset matrix with a recyclable or renewable matrix, such as bio-based resin. However, the mechanical properties of composites made with bio-based resin should be carefully experimentally assessed to guarantee a safe design and the structural integrity of the components. In this work, the quasi-static mechanical properties of composite specimens (eight layers of carbon fiber fabric) made with commercially available epoxy and a bio-based epoxy resins (31% bio content) are compared. Tensile tests on the investigated resins and tensile, compression, shear and flexural tests have been carried out on composite laminates manufactured with the two investigated resins. A finite element model has been calibrated in the LS-Dyna environment using the experimentally assessed mechanical properties. The experimental results have proven that the two composites showed similar quasi-static properties, proving that bio-based composite materials can be reliably employed as a substitute for epoxy resins without affecting the structural integrity of the component but lowering their carbon footprint

Assessment of residual elastic properties of a damaged composite plate with combined damage index and finite element methods

In structural component applications the use of composite materials is increasing thanks to their optimal mechanical characteristics. However, the complexity of the damage evolution in composite materials significantly limits their widespread diffusion. Non-destructive tests are thus becoming ever more important. The detecting Damage Index (DId) technique has been recently brought in the realm of the non-destructive characterization tests for components made of composite material. In contrast to other techniques, this methodology allows to quantitatively assess local residual properties. In this paper, the DId technique is adopted in combination with the finite element method. The mechanical response of two composite plates (an 8-layer twill fabric carbon/epoxy) subjected to four-point bending test is firstly used to tune a finite element model of the laminate. Then, an undamaged laminate of the same composite material is progressively damaged through repeated four-point bending tests. Local residual elastic properties are mapped on the plate through the DId technique. A continuous polynomial curve has been considered to account for the variation of the elastic modulus in the finite element model. The resulting force-displacement curve of the numerical analysis is compared to experimental data of damaged plate, resulting in very good agreement. The combination of the experimental activity and the numerical finite element analysis points out the accuracy of the DId methodology in assessing local residual elastic properties of composite materials

Implementing anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer: challenges and future perspectives

Epidermal growth factor receptor (EGFR) inhibitors are valuable therapeutics in metastatic colorectal cancer (mCRC). Anti-EGFR monoclonal antibodies (MoAbs), such as cetuximab or panitumumab, in combination with chemotherapy are effective treatment options for patients with RAS and BRAF wild-type mCRC. Nevertheless, several issues are still open concerning the optimal use of anti-EGFR drugs in the continuum of care of mCRC. Novel approaches for increasing the efficacy of anti-EGFR therapies include better molecular selection of EGFR-dependent mCRC, intensification of chemotherapy, combination of anti-EGFR MoAbs and immune checkpoint inhibitors, and reintroduction of EGFR blockade or 'rechallenge' in selected patients who have previously responded to anti-EGFR MoAb therapy. An extensive translational research program was conducted in the Cetuximab After Progression in KRAS wIld-type colorectal cancer patients-Gruppo Oncologico dell' Italia Meridionale (CAPRI-GOIM) study with the aims of determining which subgroups of patients could benefit from the continuous inhibition of EGFR, from evaluating the role of liquid biopsy-based and its concordance with tissue-based molecular testing, and from investigating novel potential mechanisms of resistance to anti-EGFR therapies. In this review, we summarize the translational and clinical findings of the CAPRI-GOIM program in the context of the current knowledge of therapeutic strategies and of ongoing research on more appropriate uses of anti-EGFR therapies in RAS and BRAF wild-type mCRC patients

Numerical Study of Carbon Nanofoam Targets for Laser-Driven Inertial Fusion Experiments

Porous materials have peculiar characteristics that are relevant for inertial confinement fusion (ICF). Among them, chemically produced foams are proved to be able to smooth the laser inhomogeneities and to increase the coupling of the laser with the target. Foams realized with other elements and techniques may prove useful as well for ICF applications. In this work, we explore the potential of a novel class of porous materials for ICF, namely, carbon nanofoams produced with the pulsed laser deposition (PLD) technique, by means of hydrodynamic numerical simulations. By comparison with a simulation of solid-density carbon, PLD nanofoams show a higher pressure at the shock front, which could make them potential good candidates as ablators for a capsule for direct-drive fusion

Role of Egfr and Axl Pathways in Mediating Proliferation and Invasiveness of Human Mesothelioma Cell Lines

n/

axl has a prognostic role in metastatic colorectal cancer mcrc and is a predictive biomarker of lack of efficacy of chemotherapy ct cetuximab in ras wild type wt patients pts

n/

Influence of low-ph beverages on the two-body wear of cad/cam monolithic materials

The aim of this in vitro study is to evaluate the effect of different acidic media on volumetric wear and surface roughness of CAD/CAM monolithic materials. Forty-eight rectangular specimens were prepared using different CAD/CAM monolithic materials: nanohybrid composite (Grandio Blocks, Voco), resin-based composite (Cerasmart, GC), lithium disilicate (E-Max, Ivoclar), and high-translucency zirconia (Katana STML, Kuraray Noritake). After storage in distilled water at 37◦ C for two days, the specimens were tested using a chewing machine with a stainless-steel ball as an antagonist (49N loads, 250,000 cycles). Testing was performed using distilled water, Coca-Cola, and Red Bull as abrasive media. Wear and surface roughness analyses of the CAD/CAM materials were performed using a 3D profilometer and analyzed with two-way analysis of variance and post hoc pairwise comparison procedures. Worn surfaces were examined using scanning electron microscopy. Resin-based materials suffered higher volumetric wear than ceramics (p = 0.00001). Water induced significantly less volumetric wear than the other tested solutions (p = 0.0014), independent of the material tested. High-translucency zirconia showed less surface roughness than all the other materials tested. The selection of monolithic CAD/CAM materials to restore worn dentition due to erosive processes could impact restorative therapy stability over time. Resin-based materials seem to be more influenced by the acidic environment when subjected to a two-body wear test

Cutaneous metastasis from colorectal cancer: Making light on an unusual and misdiagnosed event

Cutaneous metastasis from solid tumors is a rare event and usually represents a late occurrence in the natural history of an advanced visceral malignancy. Rarely, cutaneous metastasis has been described in colorectal cancer patients. The most frequent cutaneous site of colorectal metastasis is the surgical scar in the abdomen following the removal of the primary malignancy, followed by the extremities, perineum, head, neck, and penis. Metastases to the thigh and back of the trunk are anecdotical. Dermatological diagnosis of cutaneous metastasis can be quite complex, especially in unusual sites, such as in the facial skin or thorax and in cases of single cutaneous lesions since metastasis from colorectal cancer is not usually the first clinical hypothesis, leading to misdiagnosis. To date, due to the rarity of cutaneous metastasis from colorectal cancer, little evidence, most of which is based on case reports and very small case series, is currently available. Therefore, a better understanding of the clinic-pathological characteristics of this unusual metastatic site represents an unmet clinical need. We present a large series of 29 cutaneous metastases from colorectal cancer with particular concerns regarding anatomic localization and the time of onset with respect to primitive colorectal cancer and visceral metastases