Tuning the conductance of single-walled carbon nanotubes by ion irradiation in the Anderson localization regime

Carbon nanotubes are a good realization of one-dimensional crystals where basic science and potential nanodevice applications merge. Defects are known to modify the electrical resistance of carbon nanotubes. They can be present in as-grown carbon nanotubes, but controlling externally their density opens a path towards the tuning of the nanotube electronic characteristics. In this work consecutive Ar+ irradiation doses are applied to single-walled nanotubes (SWNTs) producing a uniform density of defects. After each dose, the room temperature resistance versus SWNT-length [R(L)] along the nanotube is measured. Our data show an exponential dependence of R(L) indicating that the system is within the strong Anderson localization regime. Theoretical simulations demonstrate that mainly di-vacancies contribute to the resistance increase induced by irradiation and that just a 0.03% of di-vacancies produces an increase of three orders of magnitude in the resistance of a 400 nm SWNT length.Comment: 16 pages, 4 figure

Oncological outcome after free jejunal flap reconstruction for carcinoma of the hypopharynx

It has been a common practice among the oncologist to reduce the dosage of adjuvant radiotherapy for patients after free jejunal flap reconstruction. The current aims to study potential risk of radiation to the visceral flap and the subsequent oncological outcome. Between 1996 and 2010, consecutive patients with carcinoma of the hypopharynx requiring laryngectomy, circumferential pharyngectomy and post-operative irradiation were recruited. Ninety-six patients were recruited. TNM tumor staging at presentation was: stage II (40.6%), stage III (34.4%) and stage IV (25.0%). Median follow-up period after surgery was 68 months. After tumor ablation, reconstruction was performed using free jejunal flap (60.4%), pectoralis major myocutaneous (PM) flap (31.3%) and free anterolateral thigh (ALT) flap (8.3%). All patients underwent adjuvant radiotherapy within 6.4 weeks after surgery. The mean total dose of radiation given to those receiving cutaneous and jejunal flap reconstruction was 62.2 Gy and 54.8 Gy, respectively. There was no secondary ischaemia or necrosis of the flaps after radiotherapy. The 5-year actuarial loco-regional tumor control for the cutaneous flap and jejunal flap group was: stage II (61 vs. 69%, p = 0.9), stage III (36 vs. 46%, p = 0.2) and stage IV (32 vs. 14%, p = 0.04), respectively. Reduction of radiation dosage in free jejunal group adversely affects the oncological control in stage IV hypopharyngeal carcinoma. In such circumstances, tubed cutaneous flaps are the preferred reconstructive option, so that full-dose radiotherapy can be given

Photodynamic therapy of early stage oral cavity and oropharynx neoplasms: an outcome analysis of 170 patients

The indications of photodynamic therapy (PDT) of oral cavity and oropharynx neoplasms are not well defined. The main reason is that the success rates are not well established. The current paper analyzes our institutional experience of early stage oral cavity and oropharynx neoplasms (Tis-T2) to identify the success rates for each subgroup according to T stage, primary or non-primary treatment and subsites. In total, 170 patients with 226 lesions are treated with PDT. From these lesions, 95 are primary neoplasms, 131 were non-primaries (recurrences and multiple primaries). The overall response rate is 90.7% with a complete response rate of 70.8%. Subgroup analysis identified oral tongue, floor of mouth sites with more favorable outcome. PDT has more favorable results with certain subsites and with previously untreated lesions. However, PDT can find its place for treating lesions in previously treated areas with acceptable results

TP53 regulates human AlkB homologue 2 expression in glioma resistance to Photofrin-mediated photodynamic therapy

2010-2011 > Academic research: refereed > Publication in refereed journa

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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

The Deformed Complex and the Formational Units

The formational units that appear in the available geological fuegian literature, and that are found within the Deformed Complex of the Fuegian Andes, are the Metamorfita Lapataia (i.e., Lapataia Metamorphites), and the Alvear, Lemaire, Yahgan and Beauvoir formations, Estratos (strata) de Policarpo and Estratos de Bahía Tethis.As an introduction to the elements of judgment that result from this study, the mentioned set of formational units is briefly reviewed here.Fil: Acevedo, Rogelio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Alternative Local Treatment in Oral Cavity Cancer::Photodynamic Therapy

The standard treatment for early stage oral cancer is surgery with or without adjuvant radiotherapy. For some patients such treatments are not applicable, for example when adequate re-irradiation doses cannot be given due to previous therapy or when further surgery would be expected to lead to unacceptable functional morbidity. Photodynamic therapy (PDT) might be an alternative for these patients. PDT is based on the interaction of three essential components: a photosensitizer i.e. a light sensitive drug, light and oxygen. The photosensitive drug is initially not toxic, but if activated by light it can interact with oxygen resulting in the formation of highly reactive oxygen species. Reactive oxygen species can readily oxidize biomolecules leading to cell death. The penetration depth of red laser light in tissue is limited to about ~8–10 mm depending on the optical properties in the tissue. Light can be delivered by surface or, intraluminal illumination for superficial tumors and by interstitial illumination for sub mucosal bulky tumor masses. For interstitial illumination light emitting catheters are inserted directly into the tumor tissue, ensuring the possibility to treat thicker tumors. Good, curative results have been achieved in the treatment of early stage oral cancer. The results are comparable to surgery. Also, in the palliative setting, encouraging results have been achieved, with preservation of quality of life. With surface illumination the treatment has a low morbidity on the long term with good functional and cosmetic results

Impact of sentinel node status and other risk factors on the clinical outcome of head and neck melanoma patients

Objective: To determine the impact of sentinel lymph node (SLN) status and other risk factors on recurrence and overall survival in head and neck melanoma patients. Design: The SLN Working Group, based in San Francisco, Calif, with its 11 member centers, the John Wayne Cancer Institute, and The University of Texas M. D. Anderson Cancer Center pooled data on 629 primary head and neck melanoma patients who had selective sentinel lymphadenectomy. A total of 614 subjects were analyzable. All centers obtained internal review board approval and adhered to the Health Insurance Portability and Accountability Act of 1996 regulations. A Cox proportional hazards model was used to identify factors associated with overall and disease-free survival. Setting: Tertiary care medical centers. Main Outcome Measure: Clinical outcome of head and neck melanoma patients undergoing selective sentinel lymphadenectomy. Results: Overall, 10.1% (n=62) of the subjects had at least 1 positive node. Subjects with positive SLN status had significantly thicker tumors (mean thickness, 2.8 vs 2.1 mm; P Conclusion: In this multicenter study, SLN status and other risk factors have an effect on recurrence and/or overall survival