Evolution of Meteorological Conditions during a Heavy Air Pollution Event under the Influence of Shallow Foehn in Urumqi, China

The air pollution in Urumqi which is located on the northern slope of the Tianshan Mountains in northwestern China,is very serious in winter.Of particular importance is the influence of terrain-induced shallow foehn,known locally as elevated southeasterly gale(ESEG).It usually modulates atmospheric boundary layer structure and wind field patterns and produces favorable meteorological conditions conducive to hazardous air pollution.During 2013-17,Urumqi had an average of 50 d yr-1 of heavy pollution(daily average PM2.5 concentration>150μg m-3),of which 41 days were in winter.The majority(71.4%)of heavy pollution processes were associated with the shallow foehn.Based on microwave radiometer,wind profiler,and surface observations,the surface meteorological fields and boundary layer evolution during the worst pollution episode in Urumqi during 16-23 February 2013 are investigated.The results illustrate the significant role of shallow foehn in the building,strengthening,and collapsing of temperature inversions.There were four wind field patterns corresponding to four different phases during the whole pollution event.The most serious pollution phase featured shallow foehn activity in the south of Urumqi city and the appearance of an intense inversion layer below 600 m.Intense convergence caused by foehn and mountain-valley winds was sustained during most of the phase,resulting in pollutants sinking downward to the lower boundary layer and accumulating around urban area.The key indicators of such events identified in this study are highly correlated to particulate matter concentrations and could be used to predict heavy pollution episodes in the feature.

Lypd1-DTR/+: A New Mouse Model for Specifically Damaging the Type Ic Spiral Ganglion Neurons of the Cochlea

Dear Editor,Inner ear auditory neurons,which are also referred as to spiral ganglion neurons(SGNs),bridge sound-receptor hair cells(HCs)to the cochlear nucleus in the brainstem[1].Two types of SGN exist:type I SGNs(95%),which innervate inner HCs(IHCs),and type II SGNs(only 5%),which form synapses with outer HCs(OHCs)[1,2].

Fgf8^(P2A-3×GFP/+):A New Genetic Mouse Model for Specifically Labeling and Sorting Cochlear Inner Hair Cells

The cochlear auditory epithelium contains two types of sound receptors,inner hair cells(IHCs)and outer hair cells(OHCs).Mouse models for labelling juvenile and adult IHCs or OHCs exist;however,labelling for embryonic and perinatal IHCs or OHCs are lacking.Here,we generated a new knock-in Fgf8^(P2A-3×GFP/+)(Fgf8^(GFP)/+)strain,in which the expression of a series of three GFP fragments is controlled by endogenous Fgf8 cis-regulatory elements.After confirming that GFP expression accurately reflects the expression of Fgf8,we successfully obtained both embryonic and neonatal IHCs with high purity,highlighting the power of Fgf8^(GFP)/+.Furthermore,our fate-mapping analysis revealed,unexpectedly,that IHCs are also derived from inner ear progenitors expressing Insm1,which is currently regarded as an OHC marker.Thus,besides serving as a highly favorable tool for sorting early IHCs,Fgf8^(GFP)/+will facilitate the isolation of pure early OHCs by excluding IHCs from the entire hair cell pool.

Enhanced electrochemical performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3−δ)cathode via Ba-doping for intermediate-temperature solid oxide fuel cells

La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)is recognized as one of the most promising cathode materials for the highly-desired intermediatetemperature solid oxide fuel cell(IT-SOFC)technology.However,it is still challenged by polarization losses due to reduced operation temperatures.In this work,a series of Ba^(2+)-doped La0.6-xBaxSr0.4Co0.2Fe0.8O3-δ(LBSCFx,x=0.05,0.10,0.15,and 0.20)materials are successfully synthesized and their electrochemical performances are evaluated as a cathode for IT-SOFC technology.The study shows that,compared to the un-doped LSCF,the Ba^(2+)-doped LBSCF possess higher electrical conductivities at 500-800℃ and display lower polarization resistances to oxygen adsorption/dissociation.As a result,the Ni-SDC|SDC|LBSCF0.20 cell(SDC=samarium-doped cerium,Sm_(0.2)Ce_(0.8)O_(1.9))delivers a high maximum power density of 0.704 W/cm^(2)at 750℃,which is>30%higher than the Ni-SDC|SDC|LSCF cell.This work reveals that Ba^(2+)-doping is effective in enhancing oxygen catalytic activity of LSCF-based cathode materials,demonstrating a new and commercial-feasible strategy in developing high performance cathode materials for the IT-SOFC technology.

Preparation of Magnetic Microsphere-Gold Nanoparticle- Immobilized Enzyme Batch Reactor and Its Application to Enzyme Inhibitor Screening in Natural Extracts by Capillary Electrophoresis

A novel strategy for screening the enzyme inhibitors from the natural products by capillary electrophoresis （CE） with a pre column enzyme batch reactor prepared by magnetic microsphere （MB）-gold nanoparticles （AuNPs） is reported. The enzyme batch reactor was prepared by immobilizing the enzymes on the MB conjugated AuNPs （MB-AuNPs）. To demonstrate this strategy, xanthine oxidase （XOD） was employed as a model for the activity of the enzyme, inhibition study, and inhibitor screening. With the developed CE method, the enzyme activity was de- termined by the quantification of the peak area of the product. Enzyme inhibition can be read out directly from the reduced peak area of product in comparison to a reference electropherogram obtained in the absence of any inhibitor A statistical parameter Z＇ factor was recommended for evaluation of the accuracy of a drug screening system. In the present study, it was calculated to be 0.7, implying a good accuracy. The screening of two natural extracts from Cortex Phellodendri and Rhizoma Galangae showed that they were positive for XOD inhibition by the present method. Using this immobilized enzyme technology combined with CE separation not only provides the advantages such as convenience, rapidity and low cost, but also provides a new platform for discovering enzyme-inhibitor drug lead compounds.