Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 83
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 118(14)2021 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-33790008

RESUMEN

A radiative vapor condenser sheds heat in the form of infrared radiation and cools itself to below the ambient air temperature to produce liquid water from vapor. This effect has been known for centuries, and is exploited by some insects to survive in dry deserts. Humans have also been using radiative condensation for dew collection. However, all existing radiative vapor condensers must operate during the nighttime. Here, we develop daytime radiative condensers that continue to operate 24 h a day. These daytime radiative condensers can produce water from vapor under direct sunlight, without active consumption of energy. Combined with traditional passive cooling via convection and conduction, radiative cooling can substantially increase the performance of passive vapor condensation, which can be used for passive water extraction and purification technologies.

2.
Matern Child Health J ; 27(Suppl 1): 34-43, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37243807

RESUMEN

OBJECTIVES: To characterize demographics, birth parameters, and social determinants of health among mother-infant dyads affected by neonatal abstinence syndrome (NAS) in Pennsylvania. METHODS: We linked 2018-2019 NAS surveillance data to birth record data using probabilistic methods and then geospatially linked to local social determinants of health data based on residential address. We generated descriptive statistics and used multivariable mixed-effects logistic regression to model the association between maternal characteristics, birth parameters, social determinants of health, and NAS. RESULTS: In adjusted models maternal age > 24, non-Hispanic white race/ethnicity, low educational attainment, Medicaid as payor at delivery, inadequate or no prenatal care, smoking during pregnancy, and low median household income were associated with NAS. We found no significant associations between NAS and county-level measures of clinician supply, number of substance use treatment facilities, or urban/rural designation. CONCLUSIONS FOR PRACTICE: This study characterizes mother-infant dyads affected by NAS using linked non-administrative, population data for Pennsylvania. Results demonstrate a social gradient in NAS and inequity in prenatal care receipt among mothers of infants with NAS. Findings may inform implementation of state-based public health interventions.


Asunto(s)
Síndrome de Abstinencia Neonatal , Trastornos Relacionados con Opioides , Recién Nacido , Femenino , Embarazo , Lactante , Humanos , Analgésicos Opioides/uso terapéutico , Madres , Pennsylvania/epidemiología , Trastornos Relacionados con Opioides/epidemiología , Trastornos Relacionados con Opioides/tratamiento farmacológico , Síndrome de Abstinencia Neonatal/epidemiología , Determinantes Sociales de la Salud
3.
J Public Health Manag Pract ; 29(2): 250-261, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36715597

RESUMEN

OBJECTIVES: The aim of this study was to assess the proportions and likelihood of children who receive confirmatory and follow-up blood lead testing within the recommended time frames after an initial capillary elevated blood lead level (EBLL) and confirmed EBLL, respectively, by individual and neighborhood-level sociodemographic characteristics. DESIGN: We linked and used blood testing and sociodemographic characteristics data from a Pennsylvania birth cohort including children born between 2017 and 2018. Generalized linear mixed models were constructed to examine the associations between sociodemographic factors and having recommended confirmatory and follow-up testing. SETTING: A population-based, retrospective cohort study. PARTICIPANTS: In this birth cohort, children who underwent at least 1 BLL test were followed up to 24 months of age. Children with a first unconfirmed (n = 6259) and confirmed BLL (n = 4213) ≥ 5 µg/dL were included in the analysis. MAIN OUTCOME MEASURE: Children had confirmatory and follow-up testing within the recommended time frames. RESULTS: Of the children with unconfirmed and confirmed EBLLs, 3555 (56.8%) and 1298 (30.8%) received confirmatory and follow-up testing, respectively. The proportions of the 2 outcome measures were lower among children experiencing certain sociodemographic disadvantages. In the univariate analyses, lower initial BLLs, older age, non-Hispanic Blacks, lower maternal educational levels, maternal Medicaid, The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) enrollment, maternal smoking, and higher quartiles of neighborhood poverty and old housing were associated with lower odds of having confirmatory and follow-up testing. However, in multivariate models, children with lower initial BLLs, older age, maternal smoking, and non-Hispanic Blacks were significantly less likely to have confirmatory and follow-up testing. CONCLUSIONS: There were deficiencies in having recommended confirmatory and follow-up blood lead testing among children, especially those with sociodemographic disadvantages. Public health agencies and stakeholders should finetune policies to improve follow-up testing in conjunction with primary and secondary preventions for early detection and reduction of lead exposure among targeted children at risk of lead poisoning.


Asunto(s)
Intoxicación por Plomo , Plomo , Lactante , Estados Unidos , Humanos , Niño , Femenino , Estudios Retrospectivos , Estudios de Seguimiento , Intoxicación por Plomo/diagnóstico , Intoxicación por Plomo/epidemiología , Características del Vecindario
4.
Am J Public Health ; 112(S7): S706-S714, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36179293

RESUMEN

Objectives. To (1) determine the prevalence of elevated blood lead levels (EBLLs; ≥ 5 µg/dL) among newly arrived refugee children, (2) understand the demographic characteristics of refugee children with EBLLs, and (3) assess health care providers' compliance with Centers for Disease Control and Prevention (CDC) recommendations for retesting. Methods. We matched refugee demographic data (2015-2019) from the CDC's Electronic Disease Notification (EDN) system with lead-testing laboratory report data from the Pennsylvania National Electronic Disease Surveillance System using Match*Pro software. Results. Of 3833 refugee children 16 years or younger in the EDN system, matching identified 3142 children with blood lead level data. Among children with blood lead level data, 578 (18.4%) had EBLLs. Among children with EBLLs, 341 (59.0%) were male. Of the 1370 children aged 6 years or younger with blood level test results, 335 (24.5%) had initial EBLLs, and only 78 (5.7%) were retested within 3 to 6 months. Of the 335 children 6 years or younger with an initial EBLL, only 44 (13.1%) were retested within 3 to 6 months. Conclusions. Following up on refugee children with EBLLs is necessary to ensure that they do not have continued lead exposure. (Am J Public Health. 2022;112(S7):S706-S714. https://doi.org/10.2105/AJPH.2022.306856).


Asunto(s)
Intoxicación por Plomo , Refugiados , Centers for Disease Control and Prevention, U.S. , Niño , Femenino , Humanos , Lactante , Plomo , Intoxicación por Plomo/diagnóstico , Intoxicación por Plomo/epidemiología , Masculino , Pennsylvania , Estados Unidos
5.
Prev Med ; 161: 107155, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35817162

RESUMEN

Mortality due to opioid misuse and overdose has increased substantially in the United States over the past two decades. The study objective was to describe the causes of death among persons with opioid-related hospitalizations and examine survival by Hepatitis C virus (HCV) or HIV. Opioid-related hospitalization records in Pennsylvania from 2000 to 2010 were linked to death registry files to assess cause of death, and survival from first hospital discharge date to death date, or December 31, 2010. Accelerated failure time models were used to compare survival between persons with and without HCV or HIV diagnoses. Among the 136,416 individuals with an opioid-related hospitalization, 13.0% died over a median of 56 months of follow-up; the most common causes of death were circulatory diseases (26.4%) and drug overdose (23.5%). There were 27,122 (19.9%) and 3662 (2.7%) persons who had an HCV and HIV diagnosis, respectively. Among patients aged ≥20 years, those with HCV had shorter survival time compared to those without HCV, with discrepancies more pronounced at older ages. Patients with HIV also had shorter survival time (time ratio: 0.29 [95% CI: 0.26, 0.34]) compared to without HIV. These findings show that in a cohort of patients with opioid-related hospitalizations, those with HCV or HIV diagnoses have shorter survival. This has public health implications, providing further evidence that medical providers should educate patients who use opioids about the risks of HCV and HIV infection and focus prevention and treatment to decrease mortality among patients hospitalized for opioid use.


Asunto(s)
Sobredosis de Droga , Infecciones por VIH , Hepatitis C , Trastornos Relacionados con Opioides , Analgésicos Opioides/efectos adversos , Infecciones por VIH/tratamiento farmacológico , Hepacivirus , Hepatitis C/tratamiento farmacológico , Hospitalización , Humanos , Estados Unidos
6.
Nano Lett ; 21(19): 8385-8392, 2021 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-34606292

RESUMEN

The microbolometer is the cornerstone device for imaging in the long-wavelength infrared range (LWIR) at room temperature. The state-of-the-art commercial microbolometers usually have a large thermal time constant (TTC) of over 10 ms, limited by their substantial device heat capacity. Moreover, the minimal pixel size of state-of-the-art bolometer is around 10 µm by 10 µm to ensure sufficient power absorption per pixel. Here, we demonstrate an ultrafast silicon nanomembrane microbolometer with a small heat capacity of around 1.9 × 10-11J/K, which allows for its operation at a speed of over 10 kHz, corresponding to a TTC of less than 16 µs. Moreover, a compact diabolo antenna is leveraged for efficient LWIR light absorption, enabling the downscaling of the active area size to 6.2 µm by 6.2 µm. Because of the complementary metal oxide semiconductor (CMOS)-compatible fabrication processes, our demonstration here may lead to a future high-resolution and high-speed LWIR imaging solution.


Asunto(s)
Semiconductores , Silicio , Rayos Infrarrojos , Óxidos
7.
Am J Epidemiol ; 188(8): 1503-1511, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31107539

RESUMEN

Infants and children are particularly vulnerable to in utero and early-life exposures. Thus, a mother's exposures before and during pregnancy could have important consequences for her child's health, including cancer development. We examined whether birth certificate-derived maternal anthropometric characteristics were associated with increased risk of subsequent childhood cancer development, accounting for established maternal and infant risk factors. Pennsylvania birth and cancer registry files were linked by the state Department of Health, yielding a virtual cohort of births and childhood cancers from 2003 through 2016. The analysis included 1,827,875 infants (13,785,309 person-years at risk), with 2,352 children diagnosed with any cancer and 747 with leukemia before age 14 years. Children born to mothers with a body mass index (weight (kg)/height (m)2) of ≥40 had a 57% (95% confidence interval: 12, 120) higher leukemia risk. Newborn size of ≥30% higher than expected was associated with 2.2-fold and 1.8-fold hazard ratios for total childhood cancer and leukemia, respectively, relative to those with expected size. Being <30% below expected size also increased the overall cancer risk (P for curvilinearity < 0.0001). Newborn size did not mediate the association between maternal obesity and childhood cancer. The results suggest a significant role of early-life exposure to maternal obesity- and fetal growth-related factors in childhood cancer development.


Asunto(s)
Neoplasias/epidemiología , Obesidad Materna/epidemiología , Adolescente , Peso al Nacer , Índice de Masa Corporal , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Pennsylvania/epidemiología , Embarazo , Resultado del Embarazo , Sistema de Registros , Factores de Riesgo
8.
Anal Chem ; 90(1): 769-776, 2018 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-29131578

RESUMEN

While there is great interest in understanding the fate and transport of nanomaterials in the environment and in biological systems, the detection of nanomaterials in complex matrices by fluorescence methods is complicated by photodegradation, blinking, and the presence of natural organic material and other fluorescent background signals that hamper detection of fluorescent nanomaterials of interest. Optically detected magnetic resonance (ODMR) of nitrogen-vacancy (NV) centers in diamond nanoparticles provides a pathway toward background-free fluorescence measurements, as the application of a resonant microwave field can selectively modulate the intensity from NV centers in nanodiamonds of various diameters in complex materials systems using on-resonance and off-resonance microwave fields. This work represents the first investigation showing how nanoparticle diameter impacts the NV center lifetime and thereby directly impacts the accessible contrast and signal-to-noise ratio when using ODMR to achieve background-free imaging of NV-nanodiamonds in the presence of interfering fluorophores. These results provide new insights that will guide the choice of optimum nanoparticle size and methodology for background-free imaging and sensing applications, while also providing a model system to explore the fate and transport of nanomaterials in the environment.


Asunto(s)
Nanodiamantes/química , Fluorescencia , Espectroscopía de Resonancia Magnética/métodos , Nitrógeno/química , Tamaño de la Partícula
9.
Nano Lett ; 17(9): 5614-5619, 2017 09 13.
Artículo en Inglés | MEDLINE | ID: mdl-28746807

RESUMEN

Phase transitions in correlated materials can be manipulated at the nanoscale to yield emergent functional properties, promising new paradigms for nanoelectronics and nanophotonics. Vanadium dioxide (VO2), an archetypal correlated material, exhibits a metal-insulator transition (MIT) above room temperature. At the thicknesses required for heterostructure applications, such as an optical modulator discussed here, the strain state of VO2 largely determines the MIT dynamics critical to the device performance. We develop an approach to control the MIT dynamics in epitaxial VO2 films by employing an intermediate template layer with large lattice mismatch to relieve the interfacial lattice constraints, contrary to conventional thin film epitaxy that favors lattice match between the substrate and the growing film. A combination of phase-field simulation, in situ real-time nanoscale imaging, and electrical measurements reveals robust undisturbed MIT dynamics even at preexisting structural domain boundaries and significantly sharpened MIT in the templated VO2 films. Utilizing the sharp MIT, we demonstrate a fast, electrically switchable optical waveguide. This study offers unconventional design principles for heteroepitaxial correlated materials, as well as novel insight into their nanoscale phase transitions.

10.
Macromol Rapid Commun ; 38(18)2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28749034

RESUMEN

The direct self-assembly of cylinder-forming poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) block copolymer is successfully assembled into two orientations, according to the underlying guiding pattern in different areas. Lying-down and perpendicular cylinders are formed, respectively, depending on the design of chemical pattern: sparse line/space pattern or hexagonal dot array. The first chemical pattern composed of prepatterned cross-linked polystyrene (XPS) line/space structure has a period (LS ) equal to twice the intercylinder period of the block copolymer (L0 ). The PS-b-PMMA thin film on the prepared chemical template after thermal annealing forms a lying-down cylinder morphology when the width of the PS strips is less than the width of PS block in the PS-b-PMMA block copolymer. The morphology is only applicable at the discrete thickness of the PS-b-PMMA film. In addition to forming the lying-down cylinders directly on the XPS guiding pattern, the cylinder-forming block copolymer can also be assembled in a perpendicular way on the second guiding pattern (the hexagonal dot array). The block copolymer films are registered into two orientations in a single directed self-assembly process. The features of the assembled patterns are successfully transferred down to the silicon oxide substrate.


Asunto(s)
Técnicas de Química Analítica/métodos , Nanoestructuras/química , Polímeros/síntesis química , Metacrilatos/química , Polímeros/química , Poliestirenos/química
12.
Opt Express ; 24(15): 16894-903, 2016 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-27464141

RESUMEN

In this study, the light absorption property of Ge nanomembrane (Ge NM), which incorporates hydrogen (H), in near-infrared (NIR) wavelength range was analyzed. Due to the presence of a large amount of structural defects, the light absorption coefficient of the Ge layer becomes much higher (10 times) than that of bulk Ge in the wavelength range of 1000 ~1600 nm. Increased light absorption was further measured from released Ge NM that has H incorporation in comparison to that of bulk Ge, proving the enhanced light absorption coefficient of H incorporated Ge. Finally, metal-semiconductor-metal (MSM) photodetectors were demonstrated using the H incorporated Ge on GeOI.

13.
Nano Lett ; 14(2): 682-6, 2014 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-24382263

RESUMEN

Field-effect transistors (FETs) that are stretchable up to 50% without appreciable degradation in performance are demonstrated. The FETs are based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes (CNTs) as the channel, a flexible ion gel as the dielectric, and buckled metal films as electrodes. The buckling of the CNT film enables the high degree of stretchability while the flexible nature of the ion gel allows it to maintain a high quality interface with the CNTs during stretching. An excellent on/off ratio of >10(4), a field-effect mobility of 10 cm(2) · V(-1) · s(-1), and a low operating voltage of <2 V are achieved over repeated mechanical cycling, with further strain accommodation possible. Deformable FETs are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins.

14.
J Nanosci Nanotechnol ; 14(2): 1521-32, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24749439

RESUMEN

A systematic review, covering fabrication of nanoscale patterns by laser interference lithography (LIL) and their applications for optical devices is provided. LIL is a patterning method. It is a simple, quick process over a large area without using a mask. LIL is a powerful technique for the definition of large-area, nanometer-scale, periodically patterned structures. Patterns are recorded in a light-sensitive medium that responds nonlinearly to the intensity distribution associated with the interference of two or more coherent beams of light. The photoresist patterns produced with LIL are the platform for further fabrication of nanostructures and growth of functional materials used as the building blocks for devices. Demonstration of optical and photonic devices by LIL is reviewed such as directed nanophotonics and surface plasmon resonance (SPR) or large area membrane reflectors and anti-reflectors. Perspective on future directions for LIL and emerging applications in other fields are presented.


Asunto(s)
Rayos Láser , Nanoestructuras/química , Nanoestructuras/ultraestructura , Dispositivos Ópticos , Fotograbar/métodos , Refractometría/instrumentación , Resonancia por Plasmón de Superficie/instrumentación , Diseño de Equipo , Conformación Molecular/efectos de la radiación , Nanoestructuras/efectos de la radiación , Tamaño de la Partícula , Propiedades de Superficie/efectos de la radiación
15.
Health Educ Res ; 29(2): 330-9, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24399260

RESUMEN

Although studies indicate school-based HIV/AIDS education programs effectively reduce risky behaviors, only 33 states and the District of Columbia in US mandate HIV/AIDS education. Ideally, school-based HIV/AIDS education should begin before puberty, or at the latest before first sexual intercourse. In 2011, 20% US states had fewer schools teaching HIV/AIDS prevention than during 2008; this is worrisome, especially for more vulnerable minorities. A nationally representative sample of 16 410 US high-school students participating in 2009 Youth Risk Behavior Survey was analyzed. Multiple regression models assessed the association between HIV/AIDS education and risky sexual behaviors, and academic grades. HIV/AIDS education was associated with delayed age at first sexual intercourse, reduced number of sex partners, reduced likelihood to have forced sexual intercourse and better academic grades, for sexually active male students, but not for female students. Both male and female students who had HIV/AIDS education were less likely to inject drugs, drink alcohol or use drugs before last sexual intercourse, and more likely to use condoms. Minority ethnic female students were more likely to have HIV testing. The positive effect of HIV/AIDS education and different gender and race/ethnicity effects support scaling up HIV/AIDS education and further research on the effectiveness of gender-race/ethnicity-specific HIV/AIDS curriculum.


Asunto(s)
Infecciones por VIH/prevención & control , Servicios de Salud Escolar , Sexo Inseguro/prevención & control , Adolescente , Factores de Edad , Escolaridad , Etnicidad/psicología , Etnicidad/estadística & datos numéricos , Femenino , Humanos , Masculino , Grupos Raciales/psicología , Grupos Raciales/estadística & datos numéricos , Servicios de Salud Escolar/organización & administración , Educación Sexual/métodos , Factores Sexuales , Conducta Sexual/estadística & datos numéricos , Sexo Inseguro/estadística & datos numéricos
16.
ACS Appl Mater Interfaces ; 16(4): 4896-4903, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38252593

RESUMEN

Radio frequency (RF) electronics are vital components of stretchable electronics that require wireless capabilities, ranging from skin-interfaced wearable systems to implantable devices to soft robotics. One of the key challenges in stretchable electronics is achieving near-lossless transmission line technology that can carry high-frequency electrical signals between various RF components. Almost all existing stretchable interconnection strategies only demonstrate direct current or low-frequency electrical properties, limiting their use in high frequencies, especially in the MHz to GHz range. Here, we describe the design and fabrication of a simple stretchable RF transmission line strategy that integrates a quasi-microstrip structure into a stretchable serpentine microscale interconnection. We show the effects of quasi-microstrip structural dimensions on the RF performance based on detailed quantitative analysis and experimentally demonstrate the optimized device capable of carrying RF signals with frequencies of up to 40 GHz with near-lossless characteristics. To show the potential application of our transmission line in stretchable microwave electronics, we designed a single-stage power amplifier system with a gain of 9.8 dB at 9 GHz that fully utilizes our quasi-microstrip transmission line technology.

17.
J Am Dent Assoc ; 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38904648

RESUMEN

BACKGROUND: Caries is the most common chronic disease among children. In Pennsylvania, a comprehensive oral health Basic Screening Survey and assessment of the association between caries and community water fluoridation (CWF) among children have not been conducted. METHODS: From 2021 through 2022, the first Basic Screening Survey was conducted among third-grade students in Pennsylvania. Oral health and demographic data were collected. CWF data were provided by the Pennsylvania Department of Environmental Protection. The relative risk of developing caries in association with CWF was assessed using the GENMOD procedure in SAS, Version 9.4 (SAS Institute) in this cross-sectional study. RESULTS: Caries prevalence was 59.7% among 4,120 screened students. Participation in the free or reduced lunch program and CWF were each significantly associated with risk of developing caries after adjustment for age, sex, and race and ethnicity. The risk of developing caries was 33% higher among students who participated in the free or reduced lunch program than those who did not participate (relative risk, 1.33; 95% CI, 1.24 to 1.42). Students with the highest CWF coverage had a nearly 16% lower risk of developing caries than those without CWF coverage (relative risk, 0.84; 95% CI, 0.75 to 0.94). CONCLUSIONS: CWF was significantly associated with a reduced risk of developing caries. Efforts are needed to increase CWF coverage, along with promotion of oral health education and healthy dietary habits among Pennsylvania children. PRACTICAL IMPLICATIONS: Increasing CWF coverage will reduce caries burden among Pennsylvania children. Although Pennsylvania has no state laws to regulate CWF, these findings are persuasive for local municipalities to consider expanding CWF coverage.

18.
Artículo en Inglés | MEDLINE | ID: mdl-38775214

RESUMEN

OBJECTIVE: The present study aimed to investigate the specific alterations of brain networks in patients with post-stroke depression (PSD), and further assist in elucidating the brain mechanisms underlying the PSD which would provide supporting evidence for early diagnosis and interventions for the disease. METHODS: Resting-state functional magnetic resonace imaging data were acquired from 82 nondepressed stroke patients (Stroke), 39 PSD patients, and 74 healthy controls (HC). Voxel-wise degree centrality (DC) conjoined with seed-based functional connectivity (FC) analyses were performed to investigate the PSD-related connectivity alterations. The relationship between these alterations and depression severity was further examined in PSD patients. RESULTS: Relative to both Stroke and HC groups, (1) PSD showed increased centrality in regions within the default mode network (DMN), including contralesional angular gyrus (ANG), posterior cingulate cortex (PCC), and hippocampus (HIP). DC values in contralesional ANG positively correlated with the Patient Health Questionnaire-9 (PHQ-9) scores in PSD group. (2) PSD exhibited increased connectivity between these three seeds showing altered DC and regions within the DMN: bilateral medial prefrontal cortex and middle temporal gyrus and ipsilesional superior parietal gyrus, and regions outside the DMN: bilateral calcarine, ipsilesional inferior occipital gyrus and contralesional lingual gyrus, while decreased connectivity between contralesional ANG and contralesional supramarginal gyrus. Moreover, these FC alterations could predict PHQ-9 scores in PSD group. INTERPRETATION: These findings highlight that PSD was related with increased functional connectivity strength in some areas within the DMN, which might be attribute to the specific alterations of connectivity between within DMN and outside DMN regions in PSD.

19.
Opt Express ; 21(21): 24582-9, 2013 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-24150302

RESUMEN

We report ultra-compact surface-normal high-Q optical filters based on single- and double-layer stacked Fano resonance photonic crystal slabs on both Si and quartz substrates. A single layer photonic crystal filter was designed and a Q factor of 1,737 was obtained with 23 dB extinction ratio. With stacked double-layer photonic crystal configuration, the optical filter Q can increase to over 10,000,000 in design. Double-layer filters with quality factor of 9,734 and extinction ratio of 8 dB were experimentally demonstrated, for a filter design with target Q of 22,000.

20.
Prev Chronic Dis ; 10: E201, 2013 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-24286275

RESUMEN

INTRODUCTION: Philadelphia enacted its Clean Indoor Air Act (CIAA) nearly 2 years before the statewide CIAA. In this study, we assessed the economic impact of CIAAs on 4 types of food services and drinking places and addressed the predominant limitation of previous pre-post ban studies, namely the lack of control for confounders and changes in secular trends over time. METHODS: We analyzed data from Pennsylvania Department of Revenue Quarterly 1998-2011 taxable county-level revenue sales and number of food services and drinking places. Region-specific and type-specific adjusted sales and number of food services and drinking places accounted for consumer spending as a general economic indicator. Segmented regression analysis of interrupted time-series methodology assessed changes in trend and level. RESULTS: Pennsylvania CIAA had no significant effect on adjusted sales or numbers except for an increase in sales in Philadelphia for limited-service eating places and in the surrounding 4 counties for special food services. Philadelphia CIAA was associated with an increase in adjusted numbers of full-service restaurants in Philadelphia and the rest of the state, special food services in Philadelphia, and drinking places in the rest of the state, and a decrease in the number of special food services in the surrounding counties. Philadelphia CIAA had no significant effect on adjusted sales except for an increase in special food services in the rest of the state. CONCLUSION: Overall, CIAAs had no negative business-related impact and, for the most part, suggest a positive impact on restaurant sales and numbers. Our results provide further support for comprehensive CIAA ordinance for restaurants.


Asunto(s)
Contaminación del Aire Interior/legislación & jurisprudencia , Bebidas Alcohólicas/economía , Comercio/estadística & datos numéricos , Exposición a Riesgos Ambientales/prevención & control , Servicios de Alimentación/economía , Humanos , Philadelphia
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA