117 research outputs found

    Terahertz metamaterials on flexible polypropylene substrate

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; GarcĂ­a Meca, C.; MartĂ­nez Abietar, AJ. (2014). Terahertz metamaterials on flexible polypropylene substrate. Plasmonics. 9(5):1143-1147. https://doi.org/10.1007/s11468-014-9724-1S1143114795Smith DR, Padilla WJ, Vier DC, Nemat-Nasser SC, Schultz S (2000) Composite medium with simultaneously negative permeability and permittivity. Phys Rev Lett 84:4184–4187Pendry JB (2000) Negative refraction makes a perfect lens. Phys Rev Lett 85:3966–3969Zhang X, Liu Z (2008) Superlenses to overcome the diffraction limit. Nat Mater 7:435–441Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Schurig D, Mock JJ, Justice BJ, Cummer SA, Pendry JB, Starr AF, Smith DR (2006) Metamaterial electromagnetic cloak at microwave frequencies. Science 314:977–980RodrĂ­guez-CantĂł PJ, MartĂ­nez-Marco M, RodrĂ­guez-Fortuño FJ, TomĂĄs-Navarro B, Ortuño R, PeransĂ­-Llopis S, MartĂ­nez A (2011) Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon. Opt Express 19:7664–7672RodrĂ­guez-Fortuño FJ, MartĂ­nez-Marco M, TomĂĄs-Navarro B, Ortuño R, MartĂ­ J, MartĂ­nez A, RodrĂ­guez-CantĂł PJ (2011) Highly-sensitive chemical detection in the infrared regime using plasmonic gold nanocrosses. Appl Phys Lett 98:133118O’Hara FJ, Singh R, Brener I, Smirnova E, Han J, Taylor AJ, Zhang W (2008) Thin-film sensing with planar terahertz metamaterials: sensitivity and limitations. Opt Express 16:1786–1795Tao H, Landy NI, Bingham CM, Zhang X, Averitt RD, Padilla WJ (2008) A metamaterial absorber for the terahertz regime: design, fabrication and characterization. Opt Express 16:7181–7188Iwaszczuk K, Strikwerda AC, Fan K, Zhang X, Averitt RD, Jepsen PU (2012) Flexible metamaterial absorbers for stealth applications at terahertz frequencies. Opt Express 20:635–643Tao H, Bingham CM, Strikwerda AC, Pilon D, Shrekenhamer D, Landy NI, Fan K, Zhang X, Padilla WJ, Averitt RD (2008) Highly flexible wide angle of incidence terahertz metamaterial absorber: design, fabrication, and characterization. Phys Rev B 78:241103(R)Tao H, Bingham CM, Pilon D, Fan K, Strikwerda AC, Shrekenhamer D, Padilla WJ, Zhang X, Averitt RD (2010) A dual band terahertz metamaterial absorber. J Phys D: Appl Phys 43:225102Padilla WJ, Taylor AJ, Highstrete C, Lee M, Averitt RD (2006) Dynamical electric and magnetic metamaterial response at terahertz frequencies. Phys Rev Lett 96:107401Chen HT, Padilla WJ, Zide JMO, Gossard AC, Taylor AJ, Averitt RD (2006) Active terahertz metamaterial devices. Nature 444:597–600Chen HT, O’Hara FJ, Azad AK, Taylor AJ, Averitt RD, Shrekenhamer DB, Padilla WJ (2008) Experimental demonstration of frequency-agile terahertz metamaterials. Nature Photon 2:295–298Chen HT, Padilla WJ, Zide JMO, Bank SR, Gossard AC, Taylor AJ, Averitt RD (2007) Ultrafast optical switching of terahertz metamaterials fabricated on ErAs/GaAs nanoisland superlattices. Opt Lett 32:1620–1622Chen HT, Palit S, Tyler T, Bingham CM, Zide JMO, O’Hara FJ, Smith DR, Gossard AC, Averitt RD, Padilla WJ, Jokerst NM, Taylor AJ (2008) Hybrid metamaterials enable fast electrical modulation of freely propagating terahertz waves. Appl Phys Lett 93:091117Chen HT, Padilla WJ, Cich MJ, Azad AK, Averitt RD, Taylor AJ (2009) A metamaterial solid-state terahertz phase modulator. Nat Photon 3:148Driscoll T, Andreev GO, Basov DN, Palit S, Cho SY, Jokerst NM, Smith DR (2007) Tuned permeability in terahertz split-ring resonators for devices and sensors. Appl Phys Lett 91:062511Debus C, Bolivar PH (2007) Frequency selective surfaces for high sensitivity terahertz sensing. Appl Phys Lett 91:184102Al-Naib IAI, Jansen C, Koch M (2008) Thin-film sensing with planar asymmetric metamaterial resonators. Appl Phys Lett 93:083507Leonhardt U, Philbin TG (2010) Geometry and light: the science of invisibility. Dover, MineolaDi Falco A, Ploschner M, Krauss TF (2010) Flexible metamaterials at visible wavelengths. New J Phys 12:113006Tao H, Strikwerda AC, Fan K, Bingham CM, Padilla WJ, Zhang X, Averitt RD (2008) Terahertz metamaterials on free-standing highly-flexible polyimide substrates. Appl Phys 41:232004Tao H, Amsden JJ, Strikwerda AC, Fan K, Kaplan DL, Zhang X, Averitt RD, Omenetto FJ (2010) Metamaterial silk composites at terahertz frequencies. Adv Mater 22:3527–3531Chen ZC, Han NR, Pan ZY, Gong YD, Chong TC, Hong MH (2011) Tunable resonance enhancement of multi-layer terahertz metamaterials fabricated by parallel laser micro-lens array lithography on flexible substrates. Opt Mat Express 1:151–157Miyamaru F, Takeda MW, Taima K (2009) Characterization of terahertz metamaterials fabricated on flexible plastic films: toward fabrication of bulk metamaterials in terahertz region. Appl Phys Express 2:042001Peralta XG, Wanke MC, Arrington CL, Williams JD, Brener I, Strikwerda A, Averitt RD, Padilla WJ, Smirnova W, Taylor AJ, O’Hara FJ (2009) Large-area metamaterials on thin membranes for multilayer and curved applications at terahertz and higher frequencies. Appl Phys Lett 94:161113Choi M, Lee SH, Kim Y, Kang SB, Shin J, Kwak MH, Kang KY, Lee YH, Park N, Min B (2011) A terahertz metamaterial with unnaturally high refractive index. Nature 470:369–373Han NR, Chen ZC, Lim CS, Ng B, Hong MH (2011) Broadband multi-layer terahertz metamaterials fabrication and characterization on flexible substrates. Opt Express 19:6990–6998Aznabet M, Navarro-Cia N, Kuznetsov SA, Gelfand AV, Fedorinina NI, Goncharov YG, Beruete M, Mrabet OE, Sorolla M (2008) Polypropylene-substrate-based SRR- and CSRR- metasurfaces for submillimeter waves. Opt Express 16:18312–18319Padilla WJ, Aronsson MT, Highstrete C, Lee M, Taylor AJ, Averitt RD (2007) Electrically resonant terahertz metamaterials: theoretical and experimental investigations. Phys Rev B 75:041102(R)Chen HT, O’Hara FJ, Taylor AJ, Averitt RD, Highstrete C, Lee M, Padilla WJ (2007) Complementary planar terahertz metamaterials. Opt Express 15:1084–1095Pendry JB, Holden AJ, Robbins DJ, Stewart WJ (1999) Magnetism from conductors and enhanced nonlinear phenomena. IEEE Trans Microwave Theory Tech 47:2075–208

    Treatment Patterns and Use of Resources in Patients With Tuberous Sclerosis Complex: Insights From the TOSCA Registry

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    Tuberous Sclerosis Complex (TSC) is a rare autosomal-dominant disorder caused by mutations in the TSC1 or TSC2 genes. Patients with TSC may suffer from a wide range of clinical manifestations; however, the burden of TSC and its impact on healthcare resources needed for its management remain unknown. Besides, the use of resources might vary across countries depending on the country-specific clinical practice. The aim of this paper is to describe the use of TSC-related resources and treatment patterns within the TOSCA registry. A total of 2,214 patients with TSC from 31 countries were enrolled and had a follow-up of up to 5 years. A search was conducted to identify the variables containing both medical and non-medical resource use information within TOSCA. This search was performed both at the level of the core project as well as at the level of the research projects on epilepsy, subependymal giant cell astrocytoma (SEGA), lymphangioleiomyomatosis (LAM), and renal angiomyolipoma (rAML) taking into account the timepoints of the study, age groups, and countries. Data from the quality of life (QoL) research project were analyzed by type of visit and age at enrollment. Treatments varied greatly depending on the clinical manifestation, timepoint in the study, and age groups. GAB Aergics were the most prescribed drugs for epilepsy, and mTOR inhibitors are dramatically replacing surgery in patients with SEGA, despite current recommendations proposing both treatment options. mTOR inhibitors are also becoming common treatments in rAML and LAM patients. Forty-two out of the 143 patients (29.4%) who participated in the QoL research project reported inpatient stays over the last year. Data from non-medical resource use showed the critical impact of TSC on job status and capacity. Disability allowances were more common in children than adults (51.1% vs 38.2%). Psychological counseling, social services and social worker services were needed by <15% of the patients, regardless of age. The long-term nature, together with the variability in its clinical manifestations, makes TSC a complex and resource-demanding disease. The present study shows a comprehensive picture of the resource use implications of TSC

    Dermatite seborreica

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    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

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    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

    Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

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    Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

    Copernicus Marine Service ocean state report, issue 4

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    This is the final version. Available from Taylor & Francis via the DOI in this record. FCT/MCTE

    Newly Diagnosed and Growing Subependymal Giant Cell Astrocytoma in Adults With Tuberous Sclerosis Complex: Results From the International TOSCA Study

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    The onset and growth of subependymal giant cell astrocytoma (SEGA) in tuberous sclerosis complex (TSC) typically occurs in childhood. There is minimal information on SEGA evolution in adults with TSC. Of 2,211 patients enrolled in TOSCA, 220 of the 803 adults (27.4%) ever had a SEGA. Of 186 patients with SEGA still ongoing in adulthood, 153 (82.3%) remained asymptomatic, and 33 (17.7%) were reported to ever have developed symptoms related to SEGA growth. SEGA growth since the previous scan was reported in 39 of the 186 adults (21%) with ongoing SEGA. All but one patient with growing SEGA had mutations in TSC2. Fourteen adults (2.4%) were newly diagnosed with SEGA during follow-up, and majority had mutations in TSC2. Our findings suggest that surveillance for new or growing SEGA is warranted also in adulthood, particularly in patients with mutations in TSC2
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