Effects of rf breakdown on the beam in the Compact Linear Collider prototype accelerator structure

Understanding the effects of RF breakdown in high-gradient accelerator structures on the accelerated beam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) and is one of the main issues addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN. During a RF breakdown large electro-magnetic fields are generated and produce parasitic magnetic fields which interact with the accelerated beam affecting its orbit and energy. We discuss here measurements of such effects observed on an electron beam accelerated in a CLIC prototype structure. Measurements of the trajectory of bunch-trains on a nanosecond time-scale showed fast changes in correspondence of breakdown which we compare with measurements of the relative beam spots on a scintillating screen. We identify different breakdown scenarios for which we offer an explanation based also on measurements of the power at the input and output ports of the accelerator structure. Finally we present the distribution of the magnitude of the observed changes in the beam orbit and we discuss its correlation with RF power and breakdown location in the accelerator structure.Comment: 10 pages, 8 figures. We replace the previous version of the article with this one, in which we extend our discussion on the experimental set-up and on the interpretation of our measurements, on the basis of the inputs received during the review process for publication on Phys. Rev. Special Topics - Accelerators and Beams. The essence of our conclusions remain unchange

A rare case of melanosis of the hard palate mucosa in a patient with chronic myeloid leukemia

Imatinib Mesylate, also known as Gleevec or ST1-571, is a tyrosine-kinase inhibitor used as the gold standard medication for the chronic myeloid leukemia (CML); Imatinib has indeed deeply revolutionized the CML therapy allowing most patients to have a good quality of life. Despite its beneficial effects, Imatinib has significant side effects such as mucosal pigmentation. A 72-year-old female having an Imatinib induced mucosal pigmentation is presented: she has been treated with Imatinib since 2003 and only in 2014 discovered, during a routine dental visit, having a pigmented lesion on her hard palate mucosa. Histopathologically, the lesion shows the deposition of fine dark brown spherical bodies within the lamina propria and cloaked in between the collagen fibers. There was no sign of inflammation, hyperplasia, or hemorrhage in the tissu

Classification review of dental adhesive systems: from the IV generation to the universal type

Adhesive dentistry has undergone great progress in the last decades. In light of minimal-invasive dentistry, this new approach promotes a more conservative cavity design, which relies on the effectiveness of current enamel-dentine adhesives. Adhesive dentistry began in 1955 by Buonocore on the benefits of acid etching. With changing technologies, dental adhesives have evolved from no-etch to total-etch (4th and 5th generation) to self-etch (6th, 7th and 8th generation) systems. Currently, bonding to dental substrates is based on three different strategies: 1) etch-and-rinse, 2) self-etch and 3) resin-modified glass-ionomer approach as possessing the unique properties of self-adherence to the tooth tissue. More recently, a new family of dentin adhesives has been introduced (universal or multi-mode adhesives), which may be used either as etch-and-rinse or as self-etch adhesives. The purpose of this article is to review the literature on the current knowledge for each adhesive system according to their classification that have been advocated by many authorities in most operative/restorative procedures. As noted by several valuable studies that have contributed to understanding of bonding to various substrates helps clinicians to choose the appropriate dentin bonding agents for optimal clinical outcomes

Subcutaneous emphysema during root canal therapy: endodontic accident by sodium hypoclorite

Cervicofacial subcutaneous emphysema is defined as the abnormal introduction of air in the subcutaneous tissues of the head and neck. It is mainly caused by trauma, head and neck surgery, general anesthesia, and coughing or habitual performance of Valsalva manoeuvre. The occurrence of subcutaneous emphysema after dental treatment is rare, and diffusion of gas into the mediastinum is much rarer, especially when the procedure is a nonsurgical treatment. Presented here is a case of subcutaneous emphysema that occurred after sodium hypochlorite irrigation during endodontic treatment, and the description of its etiologies and prevention during nonsurgical endodontic treatment. Endodontic success can be essentially achieved via good debridement of a root canal, and an ideal endodontic irrigant is effective in removing the smear layer, opening the dentinal tubules, and producing a clean surface for closer obturation

Laser treatment of 13 benign oral vascular lesions by three different surgical techniques

Objectives: Benign Oral Vascular Lesions (BOVLs) are a group of vascular diseases characterized by congenital, inflammatory or neoplastic vascular dilations clinically evidenced as more or less wide masses of commonly dark bluish color. If traumatized BOVLs are characterized by a great risk of hemorrhage and their treatment usually requires great caution to prevent massive bleeding. In the last decades lasers have dramatically changed the way of treatment of BOVLs permitting the application of even peculiar techniques that gave interesting advantages in their management reducing hemorrhage risks. The aim of this study was to evaluate the capabilities and disadvantages of three laser assisted techniques in the management of BOVLs. Study design: In this study 13 BOVLs were treated by three different laser techniques: the traditional excisional biopsy (EB), and two less invasive techniques, the transmucosal thermocoagulation (TMT) and the intralesional photocoagulation (ILP). Two different laser devices were adopted in the study: a KTP laser (DEKA, Florence, Italy, 532nm) and a GaAlAs laser (Laser Innovation, Castelgandolfo, Italy, 808nm) selected since their great effectiveness on hemoglobin. Results: In each case, lasers permitted safe treatments of BOVLs without hemorrhages, both during the intervention and in the post-operative period. The minimally invasive techniques (TMT and ILP) permitted even the safe resolution of big lesions without tissue loss. Conclusions: Laser devices confirm to be the gold standard in BOVLs treatment, permitting even the introduction of minimal invasive surgery principles and reducing the risks of hemorrhage typical of these neoplasms. As usual in laser surgery, it is necessary a clear knowledge of the devices and of the laser-tissue interaction to optimize the results reducing risks and disadvantages

Evaluation of wound healing and postoperative pain after oral mucosa laser biopsy with the aid of compound with chlorhexidine and sodium hyaluronate: a randomized double blind clinical trial

OBJECTIVES: The aim of this study is to evaluate secondary intention healing process and postoperative pain of oral soft tissues after laser surgery with the use of a compound containing chlorhexidine and sodium hyaluronate. MATERIALS AND METHODS: This double-blind, randomized clinical study included 56 patients affected by benign oral lesions and subjected to excisional biopsy with diode laser and randomly divided into three groups. Study group (SG) received 0.2% chlorhexidine digluconate and 0.2% sodium hyaluronate treatment; control group (CG) received 0.2% chlorhexidine digluconate; and placebo group (PG) followed the same protocol, taking a neutral solution having the same organoleptic characteristics. Wound healing was evaluated using percentage healing index (PHI). Numeric rating scale (NRS) was used to evaluate postoperative pain. RESULTS: PHI (T1 = 7 days) was 67.25% for SG, 58.67% for CG, and 54.55% for PG. PHI (T2 = 14 days) was 94.35% for SG, 77.79% for CG, and 78.98% for PG. A statistically significant difference was between the groups for PHI at T2 p = 0.001. No difference was detectable for pain index. CONCLUSIONS: A solution containing sodium hyaluronate and chlorhexidine is a good support to increase wound healing by secondary intention after laser biopsy, but no differences were in postoperative perception of pain. CLINICAL RELEVANCE: The use of the tested solution can be recommended after laser oral biopsies, to achieve a healing without suture. About the postoperative pain, the compound has not showed the same results and did not have measurable effects