Standards for X-Ray Microanalysis of Calcified Structures

The ability of electron probe X-ray microanalysis (EPMA) to solve biological problems often depends on the use of a quantitative approach. EPMA allows the quantitative determination of chemical elements of biological materials by using reference standards which resemble the specimen in the mode of interaction with the electron beam. Although there is a large experience in the quantification of elements in biological thin specimens, experience with standards for X-ray microanalysis of bulk specimens is limited, especially for calcified structures where the density of the specimen is difficult to estimate. The quality of the results in EPMA depends on obtaining accurate calibration curves which allow the establishment of the relationship between the signal measured and the concentration of the element of interest. The different methods for specimen preparation and the thickness of the specimen will also determine the precise nature of the standardization technique to be adopted. The physics of the electron beam-specimen interactions impose limitations upon the accuracy of calibration, and the choice of an unstable standard can result in large errors in the quantification of elements. We have reviewed the different types of compounds that have been used as standards for biological EPMA of thin and bulk specimens and discuss their potential use for quantitative analysis of mineralized tissues, with special reference to otoconia, the calcified structures of the vestibular system

Patient-reported outcomes and therapeutic affordances of social media findings from a global online survey of people with chronic pain

BACKGROUND: Patient-reported outcomes (PROs) from social media use in chronic disease management continue to emerge. While many published articles suggest the potential for social media is positive, there is a lack of robust examination into mediating mechanisms that might help explain social media’s therapeutic value. This study presents findings from a global online survey of people with chronic pain (PWCP) to better understand how they use social media as part of self-management. OBJECTIVE: Our aim is to improve understanding of the various health outcomes reported by PWCP by paying close attention to therapeutic affordances of social media. We wish to examine if demographics of participants underpin health outcomes and whether the concept of therapeutic affordances explains links between social media use and PROs. The goal is for this to help tailor future recommendations for use of social media to meet individuals’ health needs and improve clinical practice of social media use. METHODS: A total of 231 PWCP took part in a global online survey investigating PROs from social media use. Recruited through various chronic disease entities and social networks, participants provided information on demographics, health/pain status, social media use, therapeutic affordances, and PROs from use. Quantitative analysis was performed on the data using descriptive statistics, cross-tabulation, and cluster analysis. RESULTS: The total dataset represented 218 completed surveys. The majority of participants were university educated (67.0%, 146/218) and female (83.9%, 183/218). More than half (58.7%, 128/218) were married/partnered and not working for pay (75.9%, 88/116 of these due to ill health). Fibromyalgia (46.6%, 55/118) and arthritis (27.1%, 32/118) were the most commonly reported conditions causing pain. Participants showed a clear affinity for social network site use (90.0%, 189/210), followed by discussion forums and blogs. PROs were consistent, suggesting that social media positively impact psychological, social, and cognitive health. Analysis also highlighted two strong correlations linking platform used and health outcomes (particularly psychological, social, and cognitive) to (1) the narrative affordance of social media and (2) frequency of use of the platforms. CONCLUSIONS: Results did not uncover definitive demographics or characteristics of PWCP for which health outcomes are impacted. However, findings corroborate literature within this domain suggesting that there is a typical profile of people who use social media for health and that social media are more suited to particular health outcomes. Exploration of the relationship between social media’s therapeutic affordances and health outcomes, in particular the narration affordance, warrants further attention by patients and clinicians

Research highlights from the 2018 European Respiratory Society International Congress: Airway disease

The annual European Respiratory Society (ERS) International Congress (held in Paris in 2018) was once again a platform for discussion of the highest-quality scientific research, cutting-edge techniques and innovative new therapies within the respiratory field. This article discusses only some of the high-quality research studies presented at this year’s Congress, with a particular focus on airway diseases including asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis and cough, as presented through Assembly 5 of the ERS (Airway Diseases: Asthma and COPD). The authors establish the key take-home messages of these studies, compare their findings and place them in the context of current understanding.Health Research Boar

Work-Related Asthma: Diagnosis and Prognosis of Immunological Occupational Asthma and Work-Exacerbated Asthma

Abstract The incidence and prevalence of asthma are increasing. One reason for this trend is the rise in adult-onset asthma, especially occupational asthma, which is 1 of the 2 forms of work-related asthma. Occupational asthma is defined as asthma caused by agents that are present exclusively in the workplace. The presence of pre-existing asthma does not rule out the possibility of developing occupational asthma. A distinction has traditionally been made between immunological occupational asthma (whether IgE-mediated or not) and nonimmunological occupational asthma caused by irritants, the most characteristic example of which is reactive airway dysfunction syndrome. The other form of work-related asthma is known as work-exacerbated asthma, which affects persons with pre-existing or concurrent asthma that is worsened by work-related factors. It is important to differentiate between the 2 entities because their treatment, prognosis, and medical and social repercussions can differ widely. In this review, we discuss diagnostic methods, treatment, and avoidance/nonavoidance of the antigen in immunological occupational asthma and work-exacerbated asthma. Key words: Specific inhalation challenge. Peak expiratory flow. Workplace. Irritants. Resumen La incidencia y prevalencia del asma van en aumento. El asma de inicio en la edad adulta y especialmente el asma ocupacional (AO) podrían ser una de las causas que influyeran en este incremento. El AO, una de las dos formas de asma relacionada con el trabajo (ART), se define como el asma causada por agentes que están presentes exclusivamente en el lugar de trabajo. Clásicamente, se ha realizado una distinción entre AO inmunológica (mediada o no por un mecanismo IgE) y AO no inmunológica causada por irritantes, cuyo ejemplo más característico es el síndrome reactivo de disfunción de la vía aérea. La presencia de asma previa no descarta la posibilidad de desarrollar AO. El asma exacerbada por el trabajo (AET) es la otra forma de ART y se define como aquel asma pre-existente o concurrente que empeora por factores relacionados con el trabajo. Diferenciar estas dos entidades es importante ya que su tratamiento, pronóstico y repercusiones médica y social, pueden diferir ampliamente. En esta revisión se discuten los diversos métodos diagnósticos, tratamientos y las diferentes estrategias de evitación / no evitación del antígeno tanto en el AO inmunológica como en el AET. Palabras clave: Prueba de provocación bronquial específica. Pico flujo espiratorio. Lugar de trabajo. Irritantes. X Muñoz, et al

Steady state free radical budgets and ozone photochemistry during TOPSE

A steady state model, constrained by a number of measured quantities, was used to derive peroxy radical levels for the conditions of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign. The analysis is made using data collected aboard the NCAR/NSF C-130 aircraft from February through May 2000 at latitudes from 40° to 85°N, and at altitudes from the surface to 7.6 km. HO2 + RO2 radical concentrations were measured during the experiment, which are compared with model results over the domain of the study showing good agreement on the average. Average measurement/model ratios are 1.04 (σ = 0.73) and 0.96 (σ = 0.52) for the MLB and HLB, respectively. Budgets of total peroxy radical levels as well as of individual free radical members were constructed, which reveal interesting differences compared to studies at lower latitudes. The midlatitude part of the study region is a significant net source of ozone, while the high latitudes constitute a small net sink leading to the hypothesis that transport from the middle latitudes can explain the observed increase in ozone in the high latitudes. Radical reservoir species concentrations are modeled and compared with the observations. For most conditions, the model does a good job of reproducing the formaldehyde observations, but the peroxide observations are significantly less than steady state for this study. Photostationary state (PSS) derived total peroxy radical levels and NO/NO2ratios are compared with the measurements and the model; PSS-derived results are higher than observations or the steady state model at low NO concentrations

Limits on Associated Production of Visibly and Invisibly Decaying Higgs Bosons from Z Decays

Many extensions of the standard electroweak model Higgs sector suggest that the main Higgs decay channel is "invisible", for example, $h \to J J$ where $J$ denotes the majoron, a weakly interacting pseudoscalar Goldstone boson associated to the spontaneous violation of lepton number. In many of these models the Higgs boson may also be produced in association to a massive pseudoscalar boson (HA), in addition to the standard Bjorken mechanism (HZ). We describe a general strategy to determine limits from LEP data on the masses and couplings of such Higgs bosons, using the existing data on acoplanar dijet events as well as data on four and six $b$ jet event topologies. For the sake of illustration, we present constraints that can be obtained for the ALEPH data.Comment: FTUV/94-36, IFIC/94-31 TIFR/TH/94--25, 12 pages + 4 figures (included as ps files at the end

Single-molecule photobleaching probes the exciton wave function in a multichromophoric system

Ajuts: This work has been supported by the EC Program IHP- 99 (HPMF-CT-2002-01698)The exciton wave function of a trichromophoric system is investigated by means of single molecule spectroscopy at room temperature. Individual trimers exhibit superradiance and loss of vibronic structure in emission spectrum, features proving exciton delocalization. We identify two distinct photodegradation pathways for single trimers upon sequential photobleaching of the chromophores. The rate of each pathway is a measure for the contribution of the separate dyes to the collective excited state of the system, in this way probing the wave function of the delocalized exciton

Heterogeneous N2O5 Uptake During Winter: Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of Current Parameterizations

Nocturnal dinitrogen pentoxide (N2O5) heterogeneous chemistry impacts regional air quality and the distribution and lifetime of tropospheric oxidants. Formed from the oxidation of nitrogen oxides, N2O5 is heterogeneously lost to aerosol with a highly variable reaction probability, γ(N2O5), dependent on aerosol composition and ambient conditions. Reaction products include soluble nitrate (HNO3 or NO3−) and nitryl chloride (ClNO2). We report the first‐ever derivations of γ(N2O5) from ambient wintertime aircraft measurements in the critically important nocturnal residual boundary layer. Box modeling of the 2015 Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) campaign over the eastern United States derived 2,876 individual γ(N2O5) values with a median value of 0.0143 and range of 2 × 10−5 to 0.1751. WINTER γ(N2O5) values exhibited the strongest correlation with aerosol water content, but weak correlations with other variables, such as aerosol nitrate and organics, suggesting a complex, nonlinear dependence on multiple factors, or an additional dependence on a nonobserved factor. This factor may be related to aerosol phase, morphology (i.e., core shell), or mixing state, none of which are commonly measured during aircraft field studies. Despite general agreement with previous laboratory observations, comparison of WINTER data with 14 literature parameterizations (used to predict γ(N2O5) in chemical transport models) confirms that none of the current methods reproduce the full range of γ(N2O5) values. Nine reproduce the WINTER median within a factor of 2. Presented here is the first field‐based, empirical parameterization of γ(N2O5), fit to WINTER data, based on the functional form of previous parameterizations

Anthropogenic Control over Wintertime Oxidation of Atmospheric Pollutants

Anthropogenic air pollutants such as nitrogen oxides (NO(x) = NO + NO(2)), sulfur dioxide (SO(2)), and volatile organic compounds (VOC), among others, are emitted to the atmosphere throughout the year from energy production and use, transportation, and agriculture. These primary pollutants lead to the formation of secondary pollutants such as fine particulate matter (PM(2.5)) and ozone (O(3)) and perturbations to the abundance and lifetimes of short-lived greenhouse gases. Free radical oxidation reactions driven by solar radiation govern the atmospheric lifetimes and transformations of most primary pollutants and thus their spatial distributions. During winter in the mid and high latitudes, where a large fraction of atmospheric pollutants are emitted globally, such photochemical oxidation is significantly slower. Using observations from a highly instrumented aircraft, we show that multi-phase reactions between gas-phase NO(x) reservoirs and aerosol particles, as well as VOC emissions from anthropogenic activities, lead to a suite of atypical radical precursors dominating the oxidizing capacity in polluted winter air, and thus, the distribution and fate of primary pollutants on a regional to global scale