Stainless steel-FRCM system for strengthening of RC beams: towards a sustainable strengthening technique

Fabric-Reinforced Cementitious Matrix (FRCM) systems for strengthening concrete structures are an alternative to traditional techniques. The FRCM system is a composite material consisting of two or more layers of cement-based matrix reinforced with dry fibres in the form of open mesh or fabric. When adhered to concrete structural members the FRCM system acts as supplemental external reinforcement. Many existing Reinforced Concrete (RC) members exhibit degradation due to the carbonation of concrete and/or corrosion of internal reinforcing steel bars. These RC members can be strengthened using stainless steel, in strip format (unidirectional fibres), embedded in a cementitious based matrix. The system, named Stainless Steel-FRCM, can be applied according to the Externally Bonded (EB) technique. In order to reduce times and costs of intervention, number of used materials, as well as the amount of chemical compounds, a novel Inhibiting-Repairing-Strengthening (IRS) technique is proposed and experimentally tested. Using a suitable matrix (thixotropic mortar with passivation properties) the main three operations of steel bars corrosion  inhibition/protection, restoring of deteriorated concrete, and installation of the external strengthening can be carried out in one-step. For evaluating the effectiveness of both new strengthening system and installation technique an extensive experimental investigation was planned and developed. A part of the experimental research includes two groups of three RC beams (3.00 m and 4.80 m long): one strengthened withIRS technique, one strengthened with EB technique and one control beam. These beams were tested  under monotonic loading. Further two beams, one beam for each group, strengthened according to IRS technique, were also tested under cyclic loading. The experimental results show the validity of the proposed solution in terms of structural performance and environmental sustainability

Single-lap shear bond tests on Steel Reinforced Geopolymeric Matrix-concrete joints

YesNowadays Fiber Reinforced Polymers (FRPs) represent a well-established technique for rehabilitation of Reinforced Concrete (RC) and masonry structures. However, the severe degradation of mechanical properties of FRP under high temperature and fire as well as poor sustainability represents major weak points of organic-based systems. The use of eco-friendly inorganic geopolymeric matrices, alternative to the polymeric resins, would be highly desirable to overcome these issues. The present work aims to investigate the bond characteristic of a novel Steel Reinforced Geopolymeric Matrix (SRGM) strengthening system externally bonded to a concrete substrate having low mechanical properties. SRGM composite material consists of stainless steel cords embedded into a fireproof geopolymeric matrix. Single-lap shear tests by varying the bonded length were carried out. The main failure mode observed of SRGM-concrete joints was debonding at the fiber-matrix interface. Test results also suggest the effective bond length. On the basis of the experimental results, a cohesive bond-slip law was proposed.Part of the analyses were developed within the activities of Rete dei Laboratori Universitari di Ingegneria Sismica (ReLUIS) for the research program funded by the Dipartimento di Protezione Civile (DPC), Progetto DPC/ReLUIS 2016–AQ DPC/ReLUIS 2014–2016

MR Imaging of the Ankle and Hindfoot

Magnetic Resonance Imaging (MRI) is the diagnostic modality of choice for evaluation of traumatic ligamentous and tendinous injuries of the ankle and hindfoot. MRI is also valuable in the detection of occult bony trauma, osteochondral injuries, avascular necrosis, osteomyelitis, and a variety of other osseous conditions. This unit presents basic protocols for T1‐ and T2‐weighted sequences and short tau inversion recovery (STIR) imaging. Additional imaging following intravenous gadolinium is indicated in selected cases.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145347/1/cpmia2501.pd

Carriage of Staphylococcus aureus among food handlers: An ongoing challenge in public health

Staphylococcus aureus is a commensal bacterium known to colonize the skin, nares, and gastrointestinal tract of humans. Asymptomatic workers can contaminate food via manual contact or through respiratory secretions thus becoming the source of staphylococcal food poisoning. This gastrointestinal intoxication occurs after the ingestion of food contaminated by enterotoxin-producing Staphylococcus aureus. Although most individuals overcome the infection without medical assistance and make a full recovery, in rare cases the infection can be life-threatening. Hence, Staphylococcus aureus food contamination represents a serious problem for both the food industry and healthcare systems. In the last few decades, many studies have investigated the prevalence of carriers among food handlers. We present an overview of all investigations carried out on nasal carriers working in different food industry settings highlighting the risk associated with cross-contamination

Clinical significance of the buccal fat pad: how to determine the correct surgical indications based on preoperative analysis

Background: Despite the multitude of clinical and aesthetic uses, the correct surgical indications for buccal fat pad (BFP) removal have yet to be fully elucidated. Although the procedure is widely performed and promoted for aesthetic purpose, literature lacks of studies accounting for a proper evaluation of patients undergoing BFP removal. Methods: Between 2012 and 2016 patients seeking an improvement of the malar contour by reduction of the submalar prominence have been visited at the Department of Plastic Surgery of the Institution. A preoperative MRI was requested in order to correctly identify the volume of the BFP and the presence of a masseter muscle (MM) hypertrophy. Results: According to clinical examination and the results of the preoperative imaging, patients were offered different treatment options: patients with BFP hypertrophy underwent BFP removal through an itraoral approach; patients with MM hypertrophy received injection of 50 UI of botulinum toxin (BTX). No complications were observed in the postoperative period and all patients were satisfied with the results. Conclusions: According to the experience, midface contouring procedures should take account of both surgeons’ experience, patients’ expectations and anatomical evaluation. As such, there is no given approach suitable for all cases. Suggested visual criteria, clinical examination and imaging analysis are useful in establishing patient’s condition and determining the appropriate methods of treatment to enhance the facial profile

High prevalence of clonally diverse spa type t026 staphylococcus aureus contaminating rural eggshells

Purpose. The presence of Staphylococcus aureus in poultry and poultry products, including eggs, increases its potential to enter the food chain, resulting in foodborne diseases. In this context, eggshell colonization by staphylococci may represent a risk factor. This study aimed to investigate the contamination of rural eggshell by S. aureus and to characterize the key features of the isolated strains. Methodology. Antibiotic resistance was assessed by disc diffusion. Resistant isolates were analysed by PCR for the identification of associated genetic determinants of resistance. PCR was also used to screen for the presence of genes coding for toxins, namely, sea, sec, sei, sem, seo and tst. The genetic characterization was extended by means of agr locus typing and spa typing. Results. 34 S. aureus were isolated. Macrolide-and tetracycline-resistant strains were prevalent. All strains were susceptible to oxacillin, cefoxitin and trimethoprim-sulfamethoxazole. PCR screening for genes encoding enterotoxins detected several virulence patterns, which, together with spa-typing and agr-locus typing, allowed cluster analysis and the description of novel clones. Conclusion. Continuous monitoring of staphylococci is needed also in rural or natural settings. Increasing the number of samples and expanding the geographical region will be needed to further extend the significance of the study

Leadless pacemaker technology: clinical evidence of new paradigm of pacing

Despite continuous technological developments, transvenous pacemakers (PM) are still associated with significant immediate and long-term complications, mostly lead or pocket-related. Recent technological advances brought to the introduction in clinical practice of leadless PM for selected cohort of patients. These miniaturize devices are implanted through the femoral vein and advanced to the right ventricle, without leaving leads in place. Lack of upper extremity vascular access and/or high infective risk in patients requiring VVI pacing are the most common indications to leadless PM. The recently introduced MICRA AV leadless PM also allows ventricular synchronization through mechanical sensing of atrial contraction waves, thus solving the problem of AV synchronization. This review will discuss and summarize available clinical evidence on leadless PM, their performance compared to transvenous devices, current applications and future perspectives

FRP-RC/PC members subjected to combined actions

The capacity provisions of conventional Reinforced Concrete (RC) and Prestressed Concrete (PC) beams subjected to combined action of torsion, shear and flexure are well known and stated by international/national codes. Similar provisions lack for concrete members containing Fibre Reinforced Polymer (FRP) reinforcements. In general, there is paucity of research on the treatment of torsion combined with other stress resultants for FRP-RC/PC members. In this paper the theoretical method proposed by the Canadian standard CSA S806 for FRP-RC/PC structures is presented. The critical issues, related to this topic, such as the appropriate strength and inclination of the diagonal struts and failure criteria are critically analyzed and addressed. In order to assess the reliability of this study a comparison between available experimental data regarding FRP-RC/PC beams subjected to combined actions and their corresponding theoretical provisions derived by the CSA S806 standard is shown. Furthermore, another approach, available in literature, which is based on the space truss model, is examined and used for comparison in order to evaluate the theoretical provisions offered by this model against the tests value of the set of the beams analyzed in this study. Based on the critical analysis of the results, it can be highlighted that the CSA method is able to conservatively predict the capacity of these beams

Toxicity of oxaliplatin rechallenge in metastatic colorectal cancer.

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