Increasing external effects negate local efforts to control ozone air pollution: a case study of Hong Kong and implications for other Chinese cities.

It is challenging to reduce ground-level ozone (O3) pollution at a given locale, due in part to the contributions of both local and distant sources. We present direct evidence that the increasing regional effects have negated local control efforts for O3 pollution in Hong Kong over the past decade, by analyzing the daily maximum 8 h average O3 and Ox (=O3+NO2) concentrations observed during the high O3 season (September-November) at Air Quality Monitoring Stations. The locally produced Ox showed a statistically significant decreasing trend over 2002-2013 in Hong Kong. Analysis by an observation-based model confirms this decline in in situ Ox production, which is attributable to a reduction in aromatic hydrocarbons. However, the regional background Ox transported into Hong Kong has increased more significantly during the same period, reflecting contributions from southern/eastern China. The combined result is a rise in O3 and a nondecrease in Ox. This study highlights the urgent need for close cross-boundary cooperation to mitigate the O3 problem in Hong Kong. China's air pollution control policy applies primarily to its large cities, with little attention to developing areas elsewhere. The experience of Hong Kong suggests that this control policy does not effectively address secondary pollution, and that a coordinated multiregional program is required

Investigating freeway traffic hypercongestion between an on-ramp and its immediate upstream off-ramp

This paper applies the freeway traffic congestion dynamics proposed in Laval and Leclercq [2010. “Continuum Approximation for Congestion Dynamics Along Freeway Corridors.” Transportation Science 44 (1): 87–97] but with a modified distribution scheme of freeway merging flows to investigation of traffic hypercongestion on a freeway between an on-ramp and its immediate upstream off-ramp. The reason to make this modification is that the original merging scheme of this dynamics is found to possibly give undesired full priority to the traffic from the on-ramp and also occasionally make the resulting flow going through the merge greater than the available capacity. Traffic hypercongestion in this paper refers to a state where speed and flow change in the same direction as density varies. A homogeneous freeway segment chosen for this investigation includes an on-ramp and an off-ramp, which may correspond to a freeway passing by a city or town, with an off-ramp lying upstream towards the city and an on-ramp downstream. The entry flow from the upstream approach of the freeway was fixed and constant within the time horizon while both deterministic and random on-ramp inflow rates were used in this investigation. Then the formation and dissipation of traffic hypercongestion is investigated as on-ramp demand and off-ramp departure profiles vary. The first finding of this investigation is that the density in the hypercongestion area behind the merge never reached the jam density. Second, the hypercongested area continued to grow as long as the sum of the demand from the upstream of the freeway and that from the on-ramp was greater than the available capacity at the merge. Third, as long as the rate of flow leaving from the freeway via the off-ramp was not smaller than the entry flow rates from the on-ramp, no hypercongestion had been observed. In addition, in analysing the numerical results, a series of discussions was carried out to build the linkage between the on- and off-ramp flow profiles and the generated and attracted demand of the city plus its adjacent area the two ramps served for; these discussions suggest that the balanced generated and attracted demand of the city plus its adjacent area can reduce or even remove traffic hypercongestion behind the merge on the chosen freeway segment.postprin

Tetramethylpyrazine attenuates oleic acid-induced acute lung injury/acute respiratory distress syndrome through the downregulation of nuclear factor-kappa B (NF-kB) activation in rats

The aim of this study was to investigate the anti-inflammatory activities of tetramethylpyrazine (TMP) in the mice model of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) induced by oleic acid (0.15 ml/kg, intravenous (i.v.)). We report here that TMP (given at 160 mg/kg intraperitoneal (i.p.)) exerts potent anti-inflammatory effects in this model. After 4, 8 and 12 h, animal model reaction was observed and bronchoalveolar lavage fluid was obtained to measure proinflammatory cytokines (tumor necrosis factor α, interleukin 1β) and proteins by enzyme-linked immunosorbent assay and bicinchoninic acid protein assay kit, respectively. The protein expression of NF-kB in the lung was measured by immunohistochemistry and Western blotting. The results showed an increase in tumor necrosis factor α and interleukin 1β in the ALI/ARDS rat models. The activation of NF-kB was suppressed by TMP in the ALI/ARDS rats. The suppression of those molecules is controlled by NF-kB. These findings support the hypothesis that TMP inhibits the inflammatory process in the lung tissue through the suppression of NF-kB activation. Nevertheless, further investigations are required to determine the potential clinical usefulness of TMP in the adjunctive therapy for ARDS.Key words: Tetramethylpyrazine, acute lung injury/acute respiratory distress syndrome, inflammatory factors, NF-kB

Superconductivity in iron telluride thin films under tensile stress

By realizing in thin films a tensile stress state, superconductivity of 13 K was introduced into FeTe, an non-superconducting parent compound of the iron pnictides and chalcogenides, with transition temperature higher than that of its superconducting isostructural counterpart FeSe. For these tensile stressed films, the superconductivity is accompanied by the softening of the first-order magnetic and structural phase transition; and also, the in-plane extension and out-of-plane contraction are universal in all FeTe films independent of sign of lattice mismatch, either positive or negative. Moreover, the correlations were found exist between the transition temperatures and the tetrahedra bond angles in these thin films.Comment: 4 pages, 4 figures, accepted by Physical Review Letter

An environmentally friendly solution-processed ZrLaO gate dielectric for large-area applications in the harsh radiation environment

In this work, an eco-friendly aqueous solution-processed ZrLaO dielectric is demonstrated for large-area application in the harsh radiation environment. Appropriate La doping (10% La) into ZrOx could suppress the formation of Vo and improve the InOx/ZrLaO interface. The Zr0.9La0.1Oy thin films remained stable under 144 krad (SiO2) gamma-ray irradiation, no distinct composition variation or property degradation were observed. The resistor-loaded inverter based on InOx/Zr0.9La0.1Oy TFT demonstrated full swing characteristics with a gain of 13.3 at 4 V and remained 91% gain after 103 krad (SiO2) irradiation

Signal Transduction Pathways in the Pentameric Ligand-Gated Ion Channels

The mechanisms of allosteric action within pentameric ligand-gated ion channels (pLGICs) remain to be determined. Using crystallography, site-directed mutagenesis, and two-electrode voltage clamp measurements, we identified two functionally relevant sites in the extracellular (EC) domain of the bacterial pLGIC from Gloeobacter violaceus (GLIC). One site is at the C-loop region, where the NQN mutation (D91N, E177Q, and D178N) eliminated inter-subunit salt bridges in the open-channel GLIC structure and thereby shifted the channel activation to a higher agonist concentration. The other site is below the C-loop, where binding of the anesthetic ketamine inhibited GLIC currents in a concentration dependent manner. To understand how a perturbation signal in the EC domain, either resulting from the NQN mutation or ketamine binding, is transduced to the channel gate, we have used the Perturbation-based Markovian Transmission (PMT) model to determine dynamic responses of the GLIC channel and signaling pathways upon initial perturbations in the EC domain of GLIC. Despite the existence of many possible routes for the initial perturbation signal to reach the channel gate, the PMT model in combination with Yen's algorithm revealed that perturbation signals with the highest probability flow travel either via the β1-β2 loop or through pre-TM1. The β1-β2 loop occurs in either intra- or inter-subunit pathways, while pre-TM1 occurs exclusively in inter-subunit pathways. Residues involved in both types of pathways are well supported by previous experimental data on nAChR. The direct coupling between pre-TM1 and TM2 of the adjacent subunit adds new insight into the allosteric signaling mechanism in pLGICs. © 2013 Mowrey et al