Terahertz Leaky-Wave Antennas Based on Metasurfaces and Tunable Materials

Terahertz frequencies are increasingly gaining attention due to the recent efforts made in narrowing the technological gap among microwave and optical components. Still the demand of efficient THz antennas is high, due to the difficulty in obtaining directive patterns and good radiation efficiencies with planar, low-cost, easy-to-fabricate designs. In this regard, leaky-wave antennas have recently been investigated in the THz range, showing very interesting radiating features. Specifically, the combination of the leaky-wave antenna design with the use of metamaterials and metasurfaces seems to offer a promising platform for the development of future THz antenna technologies. In this Chapter, we focus on three different classes of leaky-wave antennas, based on either metasurfaces or tunable materials, namely graphene and nematic liquid crystals. While THz leaky-wave antennas based on homogenized metasurfaces are shown to be able to produce directive patterns with particularly good efficiencies, those based on graphene or nematic liquid crystals are shown to be able to dynamically reconfigure their radiating features. The latter property, although being extremely interesting, is obtained at the expense of an increase of costs and fabrication complexity, as it will emerge from the results of the presented study

Guidelines for the prevention of intravascular catheter-related infections

"This report provides health-care practitioners with background information and specific recommendations to reduce the incidence of intravascular catheter-related bloodstream infections (CRBSI). These guidelines replace the Guideline for Prevention of Intravascular Device-Related Infections, which was published in 1996. The Guidelines for the Prevention of Intravascular Catheter-Related Infections have been developed for practitioners who insert catheters and for persons who are responsible for surveillance and control of infections in hospital, outpatient, and home health-care settings. This report was prepared by a working group composed of professionals representing the disciplines of critical care medicine, infectious diseases, health-care infection control, surgery, anesthesiology, interventional radiology, pulmonary medicine, pediatrics, and nursing. The working group was led by the Society of Critical Care Medicine (SCCM), in collaboration with Infectious Disease Society of America (IDSA), Society for Healthcare Epidemiology of America (SHEA), Surgical Infection Society (SIS), American College of Chest Physicians (ACCP), American Thoracic Society (ATS), American Society of Critical Care Anesthesiologists (ASCCA), Association for Professionals in Infection Control and Epidemiology (APIC), Infusion Nurses Society (INS), Oncology Nursing Society (ONS), Society of Cardiovascular and Interventional Radiology (SCVIR), American Academy of Pediatrics (AAP), and the Healthcare Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention (CDC). The recommendations presented in this report reflect consensus of HICPAC and other professional organizations." - p. 1-2Introduction -- Intravascular catheter-related infections in adult and pediatric patients: an overview -- Epidemiology and microbiology -- Pathogenesis -- Strategies for prevention of catheter-related infections in adult and pediatric patients -- Replacement of catheters -- Special considerations for intravascular catheter-related infections in pediatric patients -- Recommendations for placement of intravascular catheters in adults and children -- References -- Appendix A: Examples of clinical definitions for catheter-related infections -- Appendix B: Summary of recommended frequency of replacements for catheters, dressings, administration sets, and fluidsprepared by Naomi P. O'Grady...[et al.]."August 9, 2002."The material in this report was prepared for publication by the National Center for Infectious Diseases, James M. Hughes, M.D., Director; Division of Healthcare Quality Promotion, Steven L. Solomon, M.D., Acting Director.Also available via the World Wide Web.Includes bibliographical references (p. 19- 26)

Computation of layered mixed potentials for the accurate and efficient analysis of periodic printed structures

International audienceOriginal acceleration procedures are proposed for the efficient calculation of the vertical components of the dyadic and scalar mixed-potential layered-media periodic Green's functions for various types of periodic structures. The extraction of suitable asymptotic terms, i.e., quasi-static images, is performed in order to speed up the convergence of the relevant spectral series. The extracted terms can be expressed as potentials for array of half-plane and half-line sources, depending on the type of the considered periodic Green's function. The relevant numerical results show the remarkable improvements in the efficiency of the approach

Air Pollution, Smoking, and Plasma Homocysteine

BACKGROUND: Mild hyperhomocysteinemia is independently associated with an increased risk of cardiovascular disease. Air pollution exposure induces short-term inflammatory changes that may determine hyperhomocysteinemia, particularly in the presence of a preexisting proinflammatory status such as that found in cigarette smokers. OBJECTIVE: We examined the relation of air pollution levels with fasting and postmethionine-load total homocysteine (tHcy) in 1,213 normal subjects from Lombardia, Italy. METHODS: We obtained hourly concentrations of particulate matter < 10 μm in aerodynamic diameter (PM(10)) and gaseous pollutants (carbon monoxide, nitrogen dioxide, sulfur dioxide(,) ozone) from 53 monitoring sites covering the study area. We applied generalized additive models to compute standardized regression coefficients controlled for age, sex, body mass index, smoking, alcohol, hormone use, temperature, day of the year, and long-term trends. RESULTS: The estimated difference in tHcy associated with an interquartile increase in average PM(10) concentrations in the 24 hr before the study was nonsignificant [0.4%; 95% confidence interval (CI), −2.4 to 3.3 for fasting; and 1.1%, 95% CI, −1.5 to 3.7 for postmethionine-load tHcy]. In smokers, 24-hr PM(10) levels were associated with 6.3% (95% CI, 1.3 to 11.6; p < 0.05) and 4.9% (95% CI, 0.5 to 9.6; p < 0.05) increases in fasting and postmethionine-load tHcy, respectively, but no association was seen in nonsmokers (p-interaction = 0.005 for fasting and 0.039 for postmethionine-load tHcy). Average 24-hr O(3) concentrations were associated with significant differences in fasting tHcy (6.7%; 95% CI, 0.9 to 12.8; p < 0.05), but no consistent associations were found when postmethionine-load tHcy and/or 7-day average O(3) concentrations were considered. CONCLUSIONS: Air particles may interact with cigarette smoking and increase plasma homocysteine in healthy subjects

Neonatal Thyroid Function in Seveso 25 Years after Maternal Exposure to Dioxin

Andrea Baccarelli and colleagues show that maternal exposure to a dioxin following the industrial accident in Seveso, Italy in 1976 is associated with modified neonatal thyroid function even many years later

IARC Monographs: 40 Years of Evaluating Carcinogenic Hazards to Humans

Background: Recently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans. Objectives: The authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed. Discussion: We concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed. Conclusions: The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public’s health

The impact of new research technologies on our understanding of environmental causes of disease: the concept of clinical vulnerability

In spite of decades of epidemiological research, the etiology and causal patterns for many common diseases, such as breast and colon cancer or neurodegenerative diseases, are still largely unknown. Such chronic diseases are likely to have an environmental origin. However, "environmental" risks have been often elusive in epidemiological studies. This is a conundrum for current epidemiological research. On the other side, the relative contribution of genes to chronic diseases, as emerging from GWAS, seems to be modest (15-50% increase in disease risk). What is yet to be explored extensively is a model of disease based on long-term effects of low doses of environmental exposures, incorporating both genetic and acquired susceptibility ("clinical vulnerability"), and the cumulative effects of different exposures. Such a disease model would be compatible with the weak associations found by GWAS and the still elusive role of many (low-level) environmental exposures. We also propose that the introduction of "-omic" high-throughput technologies, such as transcriptomics, proteomics and metabolomics, may provide, in the next years, powerful tools to investigate early effects of environmental exposures and understand the etiology of common diseases better, according to the "clinical vulnerability model". The development of "-omics", in spite of current limitations and lack of sound validation, could greatly contribute to the elucidation of the disease model we propose

IARC Monographs: 40 Years of Evaluating Carcinogenic Hazards to Humans

Background: Recently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans. Objectives: The authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed. Discussion: We concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed. Conclusions: The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public’s health. Citation: Pearce N, Blair A, Vineis P, Ahrens W, Andersen A, Anto JM, Armstrong BK, Baccarelli AA, Beland FA, Berrington A, Bertazzi PA, Birnbaum LS, Brownson RC, Bucher JR, Cantor KP, Cardis E, Cherrie JW, Christiani DC, Cocco P, Coggon D, Comba P, Demers PA, Dement JM, Douwes J, Eisen EA, Engel LS, Fenske RA, Fleming LE, Fletcher T, Fontham E, Forastiere F, Frentzel-Beyme R, Fritschi L, Gerin M, Goldberg M, Grandjean P, Grimsrud TK, Gustavsson P, Haines A, Hartge P, Hansen J, Hauptmann M, Heederik D, Hemminki K, Hemon D, Hertz-Picciotto I, Hoppin JA, Huff J, Jarvholm B, Kang D, Karagas MR, Kjaerheim K, Kjuus H, Kogevinas M, Kriebel D, Kristensen P, Kromhout H, Laden F, Lebailly P, LeMasters G, Lubin JH, Lynch CF, Lynge E, ‘t Mannetje A, McMichael AJ, McLaughlin JR, Marrett L, Martuzzi M, Merchant JA, Merler E, Merletti F, Miller A, Mirer FE, Monson R, Nordby KC, Olshan AF, Parent ME, Perera FP, Perry MJ, Pesatori AC, Pirastu R, Porta M, Pukkala E, Rice C, Richardson DB, Ritter L, Ritz B, Ronckers CM, Rushton L, Rusiecki JA, Rusyn I, Samet JM, Sandler DP, de Sanjose S, Schernhammer E, Seniori Costantini A, Seixas N, Shy C, Siemiatycki J, Silverman DT, Simonato L, Smith AH, Smith MT, Spinelli JJ, Spitz MR, Stallones L, Stayner LT, Steenland K, Stenzel M, Stewart BW, Stewart PA, Symanski E, Terracini B, Tolbert PE, Vainio H, Vena J, Vermeulen R, Victora CG, Ward EM, Weinberg CR, Weisenburger D, Wesseling C, Weiderpass E, Zahm SH. 2015. IARC Monographs: 40 years of evaluating carcinogenic hazards to humans. Environ Health Perspect 123:507–514; http://dx.doi.org/10.1289/ehp.140914