69 research outputs found

    Fabrication and characterization of thin, self‐supporting germanium single crystals

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    Thin Gesingle crystals (≀1 ÎŒm) up to 4 mm in diameter have been fabricated from epitaxialGefilmsgrown by atmospheric pressurechemical vapor deposition on Si(100) wafers. The thin Ge windows are formed by chemically etching away both the Si substrate and the region of the Gefilm near the interface that contains misfit dislocations associated with heteroepitaxialgrowth and relaxation of the Gefilms. The resulting Gefilms are comparable in crystalline quality to bulk Ge wafers, as indicated by ion channeling studies

    Coulomb Explosion and Thermal Spikes

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    A fast ion penetrating a solid creates a track of excitations. This can produce displacements seen as an etched track, a process initially used to detect energetic particles but now used to alter materials. From the seminal papers by Fleischer et al. [Phys. Rev. 156, 353 (1967)] to the present [C. Trautmann, S. Klaumunzer and H. Trinkaus, Phys. Rev. Lett. 85, 3648 (2000)], `Coulomb explosion' and thermal spike models are treated as conflicting models for describing ion track effects. Here molecular dynamics simulations of electronic-sputtering, a surface manifestation of ion track formation, show that `Coulomb explosion' produces a `heat' spike so that these are early and late aspects of the same process. Therefore, differences in scaling are due to the use of incomplete spike models.Comment: Submitted to PRL. 4 pages, 3 figures. For related movies see: http://dirac.ms.virginia.edu/~emb3t/coulomb/coulomb.html PACS added in new versio

    Staphylococcal Panton-Valentine Leucocidin as a Major Virulence Factor Associated to Furuncles

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    Panton-Valentine Leucocidin (PVL), one of the ÎČ-barrel pore-forming staphylococcal leucotoxins, is known to be associated to furuncles and some severe community pneumonia. However, it is still uncertain how many other virulence factors are also associated to furuncles and what the risk factors of furuncles are in immuno-compromised status of patients, especially the HIV (+) patients. In this paper, we use antigen immunoprecipitation and multiplex PCR approach to determine the presence of 19 toxins, 8 adhesion factors and the PFGE profiles associated to furuncles in three independent patient study groups of S. aureus (SA) isolates collected from the Cayenne General Hospital (French Guiana). The patient groups were made of: 16 isolates from HIV (−) patients, 9 from HIV (+) patients suffering from furuncles, and 30 control isolates from patients with diverse secondary infected dermatitis. Our data reveals that the majority (96%) of SA strains isolated from HIV patient-derived furuncles significantly produced PVL (p<10−7), whereas only 10% of SA strains produced this toxin in secondary infected dermatosis. A high prevalence of LukE-LukD-producing isolates (56 to 78%) was recorded in patient groups. Genes encoding clumping factor B, collagen- and laminin-binding proteins (clfB, cna, lbp, respectively) were markedly frequent (30 to 55%), without being associated to a specific group. Pulse field gel electrophoresis evidenced 24 overall pulsotypes, whereas the 25 PVL-producing isolates were distributed into 15 non clonal fingerprints. These pulsotypes were not specific PVL-producing isolates. PVL appears to be the major virulence factor associated to furuncles in Europe and in South America regardless of the immune status of the HIV patients

    Rhinitis in the geriatric population

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    The current geriatric population in the United States accounts for approximately 12% of the total population and is projected to reach nearly 20% (71.5 million people) by 2030[1]. With this expansion of the number of older adults, physicians will face the common complaint of rhinitis with increasing frequency. Nasal symptoms pose a significant burden on the health of older people and require attention to improve quality of life. Several mechanisms likely underlie the pathogenesis of rhinitis in these patients, including inflammatory conditions and the influence of aging on nasal physiology, with the potential for interaction between the two. Various treatments have been proposed to manage this condition; however, more work is needed to enhance our understanding of the pathophysiology of the various forms of geriatric rhinitis and to develop more effective therapies for this important patient population

    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

    Canine fossa trephine is a beneficial procedure in patients with Samter's triad

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    BACKGROUND: Canine fossa trephine (CFT) is an adjunctive technique to sinus surgery in patients with recalcitrant maxillary sinusitis. CFT allows for disease clearance in areas of the maxillary sinus that are hard to reach with standard endoscopic techniques. The objective of this study was to compare the surgical outcome of CFT to standard middle meatal antrostomy (MMA) in matched patients with the severely diseased maxillary sinus. STUDY DESIGN: Prospective clinical study METHODS: Patients undergoing sinus surgery were enrolled in either the CFT or MMA group. All patients had nasal polyps, Lund Mackay score of 2 in the maxillary sinus, and nasal endoscopy showing the maxillary sinus full of polyps. The patients were followed and the maxillary sinus was graded endoscopically at 3, 6 and 12 months after the surgery. Length of surgery, disease recurrence and need for revision surgery was documented. RESULTS: Forty-two CFTs and MMA were performed in each group. At 6 and 12 months the CFT group demonstrated statistically significant improvement in nasal endoscopy scores. Six patients recurred by the one year mark in the MMA group, 4 of which underwent revision surgery. In the CFT group 2 patients recurred, one who underwent a unilateral revision CFT. Furthermore the CFT did not prolong the surgical time and was often faster than performing a MMA. CONCLUSION: CFT allows for clearance of all gross disease in the maxillary sinus and appears to improve postoperative outcome at 6 and 12 months and decrease the need for revision surgery.K.A. Seiberling, C.A. Church, M. Tewfik, A. Foreman, D. Chang, M. Ghostine and P.J. Wormaldhttp://www.rhinologyjournal.com/abstract.php?id=105

    Fabrication and characterization of thin, self‐supporting germanium single crystals

    No full text
    Thin Gesingle crystals (≀1 ÎŒm) up to 4 mm in diameter have been fabricated from epitaxialGefilmsgrown by atmospheric pressurechemical vapor deposition on Si(100) wafers. The thin Ge windows are formed by chemically etching away both the Si substrate and the region of the Gefilm near the interface that contains misfit dislocations associated with heteroepitaxialgrowth and relaxation of the Gefilms. The resulting Gefilms are comparable in crystalline quality to bulk Ge wafers, as indicated by ion channeling studies

    Fabrication and characterization of thin, self‐supporting germanium single crystals

    No full text
    Thin Gesingle crystals (≀1 ÎŒm) up to 4 mm in diameter have been fabricated from epitaxialGefilmsgrown by atmospheric pressurechemical vapor deposition on Si(100) wafers. The thin Ge windows are formed by chemically etching away both the Si substrate and the region of the Gefilm near the interface that contains misfit dislocations associated with heteroepitaxialgrowth and relaxation of the Gefilms. The resulting Gefilms are comparable in crystalline quality to bulk Ge wafers, as indicated by ion channeling studies
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