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Rationale: Unprecedented pollution control actions during the Beijing Olympics provided a quasi-experimental opportunity to examine biologic responses to drastic changes in air pollution levels. Objectives: To determine whether changes in levels of biomarkers reflecting pulmonary inflammation and pulmonary and systemic oxidative stress were associated with changes in air pollution levels in healthy young adults. Methods: We measured fractional exhaled nitric oxide, a number of exhaled breath condensate markers (H 1 , nitrite, nitrate, and 8-isoprostane), and urinary 8-hydroxy-2-deoxyguanosine in 125 participants twice in each of the pre-(high pollution), during-(low pollution), and post-Olympic (high pollution) periods. We measured concentrations of air pollutants near where the participants lived and worked. We used mixed-effects models to estimate changes in biomarker levels across the three periods and to examine whether changes in biomarker levels were associated with changes in pollutant concentrations, adjusting for meteorologic parameters. Measurements and Main Results: From the pre-to the during-Olympic period, we observed significant and often large decreases (ranging from 24.5% to 272.5%) in levels of all the biomarkers. From the during-Olympic to the post-Olympic period, we observed significant and larger increases (48-360%) in levels of these same biomarkers. Moreover, increased pollutant concentrations were consistently associated with statistically significant increases in biomarker levels. Conclusions: These findings support the important role of oxidative stress and that of pulmonary inflammation in mediating air pollution health effects. The findings demonstrate the utility of novel and noninvasive biomarkers in the general population consisting largely of healthy individuals.Keywords: air pollution; inflammation; oxidative stress; respiratory health; the Beijing Olympics Increased air pollution concentrations have previously been associated with increased cardiorespiratory mortality and morbidity (1-5). However, observational and experimental studies in humans or animals have generated limited and somewhat inconsistent data supporting several postulated pathophysiologic pathways (6-10). One of these is the hypothesis that inhaled pollutants can react rapidly with extracelluar macromolecules or cell constituents in the airway epithelium to generate reactive oxygen or nitrogen species (e.g., free radicals and peroxides), inducing local and systemic oxidative or nitrosative stress and subsequent inflammation (11).Pulmonary inflammation and oxidative stress responses to air pollution have been examined in human studies using several noninvasive biomarkers in exhaled breath and exhaled breath condensate (EBC) (7,(12)(13)(14)(15)(16)(17)(18). Increased air pollution levels have been associated with increased levels of fractional exhaled nitric oxide (FE NO ), reflecting pulmonary inflammation, in children and the elderly (12)(13)(14)(15)(19)(20)(21)(22). Traffic pollution exposure has been associated...

BackgroundProblem-based learning (PBL), a pedagogical approach, is widely accepted in medical education. Manipulated by many factors, the internal motivation of learner is the most crucial determinant that affects the nature of the outcome, in which the influences of critical thinking (CT) remained elusive.MethodsOne hundred two third-year undergraduate medical students at Peking University were involved in this study. A Chinese version of the Critical Thinking Disposition Inventory (CTDI-CV) was used to assess the CT disposition, and the performance scores of students in PBL tutorials were compiled. A parametric bivariate correlation analysis was performed between the students’ CT scores and their PBL average scores. The PBL scores were compared between the strong and weak CT disposition groups using independent t-test. The analysis of numerical data was conducted using SPSS 16.0.ResultsCT disposition of third-year undergraduate medical students at Peking University was at a positive level, with an average score of 297.72. The total CT scores had a positive correlation with the scores of the PBL performance and its five dimensions significantly. In the majority, students with Strong-CT disposition obtained higher scores in PBL tutorials compared with students with Weak-CT disposition. The performance of these two groups was significantly different in the Late-Half but not in the Early-Half PBL tutorials. Furthermore, a significant improvement was observed in the students with strong CT but not weak CT dispositions.ConclusionCT disposition positively correlates to a students’ PBL performance. Students with stronger CT dispositions perform better in the PBL process and obtain higher scores. Our work suggested that the open-mindedness of the CT disposition is the primary factor that determines the improvement of the preparation dimensions in the PBL process.

The rapid development of wearable devices puts forward higher requirements for mass-produced integrated smart systems that incorporate multiple electric components, such as energy supplying, multisensing, and communicating. To synchronously realize continuously self-powering, multifunctional sensing, distinguish signals from different stimuli, and productively design and fabricate a large-area sensing array, an all-fabric-based self-powered pressure–temperature-sensing electronic skin (e-skin) was prepared in this study by assembling highly flexible and compressible 3D spacer fabric (SF) and the thermoelectric poly­(3,4-ethylenedioxythiophene)­poly­(styrenesulfonate) (PEDOT:PSS). The all-fabric-based e-skin can efficiently and accurately sense the temperature with a detection resolution of 0.1 K and a response time of 1 s, as well as pressure within a wide range of 200 Pa to 200 kPa and a fast response time of 80 ms. The electricity necessary for driving the sensor can be provided by the temperature difference between the body and environment. Notably, independent voltage and current signals can be generated and read out under the simultaneous temperature–pressure stimuli. For the first time, a real waistcoat-like e-skin with electricity-generating and pressure–temperature-sensing functions on the whole area was designed and prepared by a simple and easy to scale-up production method. All of these features make the developed all-fabric self-powered sensor have very promising applications.

Pressure sensors with 3D conformability are highly desirable components for artificial electronic skin or e-textiles that can mimic natural skin, especially for application in real-time monitoring of human physiological signals. Here, a nanofiber based electronic skin with ultra-high pressure sensitivity and 3D conformability is designed and built by interlocking two elastic patterned nanofibrous membranes. The patterned membrane is facilely prepared by casting conductive nanofiber ink into a silicon mould to form an array of semi-spheroid-like protuberances. The protuberances composed of intertwined elastic POE nanofibers and PPy@PVA-co-PE nanofibers afford a tunable effective elastic modulus that is capable of capturing varied strains and stresses, thereby contributing to a high sensitivity for pressure sensing. This electronic skin-like sensor demonstrates an ultra-high sensitivity (1.24 kPa(-1)) below 150 Pa with a detection limit as low as about 1.3 Pa. The pixelated sensor array and a RGB-LED light are then assembled into a circuit and show a feasibility for visual detection of spatial pressure. Furthermore, a nanofiber based proof-of-concept wireless pressure sensor with a bluetooth module as a signal transmitter is proposed and has demonstrated great promise for wireless monitoring of human physiological signals, indicating a potential for large scale wearable electronic devices or e-skin.