Background: Oxidative stress is involved in thoracic diseases and health responses to air pollution. Malondialdehyde (MDA) is a well-established marker of oxidative stress, but it may be present in unconjugated and conjugated forms. To our knowledge, no studies have conducted a systemic evaluation of both free MDA (unconjugated MDA) and total MDA (the sum of both unconjugated and conjugated MDA) across various types of human biospecimens.Methods: Free MDA and total MDA were simultaneously measured in a range of human biospecimens, including nasal fluid (N=158), saliva (N=158), exhaled breath condensate (N=40), serum (N=232), and urine (N=429). All samples were analyzed using an HPLC-fluorescence method with high sensitivity and specificity. Due to the right skewed distribution of free MDA and total MDA, we performed natural-log transformation before subsequent statistical analyses. The relationship between the natural log of free and total MDA was evaluated by R-2 of simple linear regression. T test was used for comparisons of means between two groups. One-way analysis of variance was used in combination with Tukey's test to compare the natural log of the ratio of free MDA to total MDA across various types of biospecimens.Results: For exhaled breath condensate, serum, urine, nasal fluid and saliva samples, the R-2 between free and total MDA were 0.61, 0.22, 0.59, 0.47 and 0.06, respectively; the medians of the free MDA to total MDA ratio were 48.1%, 17.4%, 9.8%, 5.1% and 3.0%, respectively; the free MDA to total MDA ratio in EBC > serum > urine > nasal fluid > saliva (P < 0.001 for pairwise comparisons).Conclusions: For exhaled breath condensate and urine samples, using either free or total MDA can provide information regarding the level of oxidative stress; however, that is not the case for serum, nasal fluid, and saliva given the low correlations between free and total MDA.
BACKGROUND: Long-term exposure to pollution can lead to an increase in the rate of decline of lung function, especially in older individuals and in those with chronic obstructive pulmonary disease (COPD), whereas shorter-term exposure at higher pollution levels has been implicated in causing excess deaths from ischaemic heart disease and exacerbations of COPD. We aimed to assess the effects on respiratory and cardiovascular responses of walking down a busy street with high levels of pollution compared with walking in a traffic-free area with lower pollution levels in older adults. METHODS: In this randomised, crossover study, we recruited men and women aged 60 years and older with angiographically proven stable ischaemic heart disease or stage 2 Global initiative for Obstructive Lung Disease (GOLD) COPD who had been clinically stable for 6 months, and age-matched healthy volunteers. Individuals with ischaemic heart disease or COPD were recruited from existing databases or outpatient respiratory and cardiology clinics at the Royal Brompton & Harefield NHS Foundation Trust and age-matched healthy volunteers using advertising and existing databases. All participants had abstained from smoking for at least 12 months and medications were taken as recommended by participants' doctors during the study. Participants were randomly assigned by drawing numbered disks at random from a bag to do a 2 h walk either along a commercial street in London (Oxford Street) or in an urban park (Hyde Park). Baseline measurements of participants were taken before the walk in the hospital laboratory. During each walk session, black carbon, particulate matter (PM) concentrations, ultrafine particles, and nitrogen dioxide (NO2) concentrations were measured. FINDINGS: Between October, 2012, and June, 2014, we screened 135 participants, of whom 40 healthy volunteers, 40 individuals with COPD, and 39 with ischaemic heart disease were recruited. Concentrations of black carbon, NO2, PM10, PM2.5, and ultrafine particles were higher on Oxford Street than in Hyde Park. Participants with COPD reported more cough (odds ratio [OR] 1.95, 95% CI 0.96-3.95; p<0.1), sputum (3.15, 1.39-7.13; p<0.05), shortness of breath (1.86, 0.97-3.57; p<0.1), and wheeze (4.00, 1.52-10.50; p<0.05) after walking down Oxford Street compared with Hyde Park. In all participants, irrespective of their disease status, walking in Hyde Park led to an increase in lung function (forced expiratory volume in the first second [FEV1] and forced vital capacity [FVC]) and a decrease in pulse wave velocity (PWV) and augmentation index up to 26 h after the walk. By contrast, these beneficial responses were attenuated after walking on Oxford Street. In participants with COPD, a reduction in FEV1 and FVC, and an increase in R5-20 were associated with an increase in during-walk exposure to NO2, ultrafine particles and PM2.5, and an increase in PWV and augmentation index with NO2 and ultrafine particles. In healthy volunteers, PWV and augmentation index were associated both with black carbon and ultrafine particles. INTERPRETATION: Short-term exposure to traffic pollution prevents the beneficial cardiopulmonary effects of walking in people with COPD, ischaemic heart disease, and those free from chronic cardiopulmonary diseases. Medication use might reduce the adverse effects of air pollution in individuals with ischaemic heart disease. Policies should aim to control ambient levels of air pollution along busy streets in view of these negative health effects. FUNDING: British Heart Foundation.
Britain’s loss of its Southeast Asian colonies during World War Two (WWII), especially the fall of Malaya and Singapore, is a relatively well-studied topic. While existing scholarship has covered the military failure in great detail, researchers have not paid equal attention to the disorganization of the colonial administration, which played a no less important role in the years leading up to the defeat. Based on his meticulous research in British archives, Ronald McCrum has filled the gap by scrutinizing the ‘irresponsible and incompetent’ behaviors of the civilian authorities. He argues that by pursuing different priorities, the colonial government failed to take necessary measures to counter the growing threat of the Japanese. Besides the fact that the British civilian administration was in disarray within itself, their poor relationship with the military also greatly hindered joint efforts to augment the defense against the imminent invasion, which ultimately led to astonishing casualties when the war broke out.
This review reports on the progress of recent developments in graphene-based microfluidics. The applications of graphene-based microfluidics that are the focus of this work are illustrated and discussed mainly with examples from detection of viruses and disease, detection of proteins and glucose, detection of contaminants, and applications in sensors and material preparation. A variety of microfluidic devices integrated with graphene are expounded and analysed. This paper will provide an expedient and valuable reference to designers researching graphene-based microfluidics for various applications.
This paper discusses the importance of a passage in book 5 of Lucretius’s De rerum natura (DRN) in relation to known Epicurean teachings during the Principate, and the significance of this disjunct between the Epicurean epic and the Epicurean teachings in the Roman world. Discussions on Lucretius' DRN 5.1011-1027 often focus on the Hobbesian reading, with particular interest in Lucretius' theoretical contribution that begins with an "original condition" of mankind to the arrival of the social contract and the formation of society. Another common strand of discussion evolves around the question whether Lucretius "had more of Epicurus' works to follow than we do," as David Sedley and Campbell assumes. Yet, as Brook Holmes pointed out, DRN 5.1011-1027 have often been used to "shore up reconstructions of Epicurean views on the nature of social relationships, about which we know relatively little." Sedley's attempt to reconstruct the Epicurea "without" using Lucretius as guide, for instance, chose to leave out our focus passage altogether, for it did not fit into any existing account of Epicurus' writings. While the relationship between our focus passage and Epicurus' own writings remain uncertain, there are two aspects that inform us of how to approach the significance of the focus passage with Roman society. The first is Arrian's account of the Stoic Epictetus, whose mockery of Epicurean positions regarding marriage and offspring illustrates a clear if not biased social perception of Epicurean views on topics of the family. The second is that some of the fragments in the Herculaneum papyri include passages showing some Epicureans discussing such topics concerning marriage, offspring, and parental affinity. This paper examines the two sets of data and consider Lucretius' account in social context. This paper takes the view that Lucretius was providing an innovative account of Epicureanist creation story that was tailored for an elite Roman audience, and the "familial topics," presented not only at DRN 5.1011-1027, but in other sections of his work as well, show a clear intention to introduce Epicureanism as a form of social discourse compatible with the circle of the Roman elite that placed emphasis on "familial topics."
In this work, room-temperature-operated ultrasensitive solution-processed perovskite photodetectors (PDs) with near infrared (NIR) photoresponse are reported. In order to enable perovskite PDs possessing extended NIR photoresponse, novel n-type low bandgap conjugated polymer, poly[(N, N'bis(2-octyldodecyl)-1,4,5,8-naphthalene diimide-2,6-diyl) (2,5-dioctyl-3,6-di(thiophen-2-yl) pyrrolo[3,4-c] pyrrole-1,4-dione-5,5'-diyl)] (NDI-DPP), which has strong absorption in the NIR region, is developed and then employed in perovskite PDs. By the formation of type II band alignment between NDI-DPP with single-wall carbon nanotubes (SWCNTs), the NIR absorption of NDI-DPP is exploited, which contributes to the NIR photoresponse for the perovskite PDs, where perovskite is incorporated with NDI-DPP and SWCNTs as well. In addition, SWCNTs incorporated with perovskite active layer can offer the percolation pathways for high charge-carrier mobility, which tremendously boosts the charge transfer in the photoactive layer, and consequently improves the photocurrent in the visible region. As a result, the perovskite PDs exhibit the responsivities of approximate to 400 and approximate to 150 mA W-1 and the detectivities of over 6 x 10(12) Jones (1 Jones = 1 cm Hz(1/2) W-1) and over 2 x 10(12) Jones in the visible and NIR regions, respectively. This work reports the development of perovskite PDs with NIR photoresponse, which is terrifically beneficial for the practical applications of perovskite PDs.