Associations between asthma trigger reports, mental health conditions, and asthma morbidity among world trade center rescue and recovery workers

Aim: There is limited information regarding asthma triggers in World Trade Center (WTC) rescue and recovery workers (RRW) or how mental health conditions affect the perception of triggers. Methods: We included 372 WTC workers with asthma. The Asthma Trigger Inventory (ATI) assessed triggers along five domains: psychological, allergens, physical activity, infection, and pollution. We administered the Structured Clinical Interview to diagnose post-traumatic stress disorder (PTSD), major depression and panic disorder (PD). The Asthma Control Questionnaire (ACQ) and Mini Asthma Quality of Life Questionnaire (AQLQ) measured asthma control and quality of life, respectively. Linear regression models were fitted to examine the association of ATI total and subdomain scores with mental health conditions as well as the percent of ACQ and AQLQ variance explained by ATI subscales. Results: The most common triggers were air pollution (75%) and general allergens (68%). PTSD was significantly associated with psychological triggers (partial r²=0.05, p < 0.01), physical activity (partial r²=0.03, p < 0.01) and air pollution (partial r²=0.02, p = 0.04) subscales while PD was significantly associated with air pollution (partial r²=0.03, p = 0.03) and general allergens (partial r²=0.02, p = 0.03). ATI subscales explained a large percentage of variance in asthma control (r²=0.37, p < 0.01) and quality of life scores (r²=0.40, p < 0.01). Psychological subscale scores explained the largest portion of the total variability in ACQ (partial r²= 0.11, p = 0.72) and AQLQ (partial r²=0.14, p = 0.64) scores. Conclusion: RRW with mental health conditions reported more asthma triggers and these triggers were associated with asthma morbidity. These data can help support interventions in RRW with asthma.

Metal-mediated linear self-assembly of porphyrins

Porphyrin derivatives are highly relevant to biological processes such as light harvesting and charge separation. Their aromatic electronic structure and their accessible HOMO-LUMO gap render porphyrins highly attractive for the development of opto- and electro-active materials. Due to the often difficult covalent synthesis of multiporphyrins, self-assembly using metal complexation as the driving force can lead to well defined objects exhibiting a controlled morphology, which will be required to analyse and understand the electronic properties of porphyrin wires. This article presents two assembly approaches, namely by peripheral coordination or by binding to a metal ion in the porphyrin core, that are efficient and well designed for future developments requiring interactions with a surface.

Acoustic emission multiplets as early warnings of fatigue failure in metallic materials

Fatigue, i.e. the failure of mechanical structures under cycling loading, remains a considerable technological challenge as it occurs unexpectedly when the structure is operating apparently in a safe and steady state regime, without external signs of mechanical deterioration. Here we report for the first time, in different metallic materials, the detection of acoustic emissions specific of fatigue crack growth. These so-called acoustic multiplets are characterized by nearly identical waveforms, signature of a unique source, are repeatedly triggered over many successive loading cycles at the same stress level, and originate from a single location. They mark the slow, incremental propagation of a fatigue crack at each cycle, or the rubbing along its faces. Being specific to fatigue cracking, they can be used as early warnings of crack propagation, which will ultimately lead to structural failure. Their detection and characterization thus open the way towards a new, reliable monitoring of the onset of fatigue cracking during mechanical tests or within structures in service.

A small spacecraft for multipoint measurement of ionospheric plasma

Measurement of ionospheric plasma is often performed by a single in situ device or remotely using cameras and radar. This article describes a small, low-resource, deployed spacecraft used as part of a local, multipoint measurement network. A B-field aligned sounding rocket ejects four of these spin-stabilized spacecraft in a cross pattern. In this application, each spacecraft carries two retarding potential analyzers which are used to determine plasma density, flow, and ion temperature. An inertial measurement unit and a light-emitting diode array are used to determine the position and orientation of the devices after deployment. The design of this spacecraft is first described, and then results from a recent test flight are discussed. This flight demonstrated the successful operation of the deployment mechanism and telemetry systems, provided some preliminary plasma measurements in a simple mid-latitude environment, and revealed several design issues.

Leaching of Conductive Species: Implications to Measurements of Electrical Resistivity

Electrical tests have been used to characterize the microstructure of porous materials, the measured electrical response being determined by the contribution of the microstructure (porosity and tortuosity) and the electrical properties of the solution (conductivity of the pore solution) inside the pores of the material. This study has shown how differences in concentration between the pore solution (i.e., the solution in the pores) and the storage solution surrounding the test specimen leads to significant transport (leaching) of the conductive ionic species between the pore solution and the storage solution. Leaching influences the resistivity of the pore solution, thereby influencing electrical measurements on the bulk material from either a surface or uniaxial bulk resistance test. This paper has three main conclusions: 1.) Leaching of conductive species does occur with concentration gradients and that a diffusion based approach can be used to estimate the time scale associated with this change. 2.) Leaching of ions in the pore solution can influence resistivity measurements, and the ratio of surface to uniaxial resistivity can be used as a method to assess the presence of leaching and 3.) An estimation of the magnitude of leaching for standardized tests of cementitious materials.