Cretaceous crown male ant reveals the rise of modern lineages.

Most described Mesozoic ants belong to stem groups that existed only during the Cretaceous period. Previously, the earliest known crown ants were dated to the Turonian (Late Cretaceous, ca. 94-90 million years ago (Ma)) deposits found in the USA, Kazakhstan, and Botswana.

[Concentration and Reactivity of Carbonyl Compounds in the Atmosphere of North China].

To reveal the characteristics of photochemical pollution in North China, adsorbing columns with 2, 4-dinitrophenylhydrazine(DNPH) were used to sample carbonyl compounds in Shijiazhuang and Xinglong between May 2018 and April 2019. The samples were analyzed by high-performance liquid chromatography to understand the composition, volume fraction, source, ·OH loss rate, and ozone formation potential of the carbonyl compounds. A total of 13 carbonyl compounds containing carbonyl groups were determined, of which acetone, formaldehyde, and acetaldehyde were highest at(6.

[Chemical Composition and Source Analysis of PM in Yuncheng, Shanxi Province in Autumn and Winter].

In order to reveal the chemical composition characteristics and pollution sources of fine particulate matter (PM) in autumn and winter in Yuncheng, PM samples were continuously collected using a four-channel small-flow particulate sampler from October 15, 2018 to March 15, 2019. The study prediminantly analyzed the chemical components of water-soluble ions, elemental carbon, organic carbon, and metal elements. Additionally, the chemical mass reconstruction method of particulate matter and the positive matrix factorization model (PMF) were combined for an in-depth discussion.

[Pollution Characteristics and Health Risk Assessment of Heavy Metals in PM Collected in Baoding].

To reveal the pollution characteristics and the health risks of the trace heavy metals in the atmospheric particles in Baoding, Hebei province, PM2.5 samples were collected using a middle volume sampler, and the mass concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb in the samples were determined by microwave digestion-inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that the PM concentration in Baoding ranged from 16.

[Pollution Characteristics and Source Apportionment of -Alkanes and PAHs in Summertime PM at Background Site of Yangtze River Delta].

To investigate the pollution characteristics and sources of organic aerosols at a background site of the Yangtze River Delta, day- and night- PM samples were collected from May 30 to August 15, 2018 in Chongming Island, China and measured for their normal alkanes (-alkanes) and polycyclic aromatic hydrocarbons (PAHs) content employing a GC-MS technique. Concentrations of PM, -alkanes, and PAHs during the entire sampling period were (33±21) μg·m, (26±44) ng·m, and (0.76±1.

[Concentration and Ecological Risk Assessment of Heavy Metals in PM Collected in Urban and Suburban Areas of Beijing].

Atmospheric PM pollution and ambient air quality were investigated in Beijing, and the ecological risks of the trace heavy metals in PM were analyzed. PM samples were collected from Dongzhimen and Huairou by a middle volume sampler, and 16 kinds of trace metals were determined by inductively couple plasma-mass spectrometry (ICP-MS). The results showed that the average concentration of PM in the urban area was 92.

[Pollution Characteristics and Source Analysis of Aromatic Compounds in Shijiazhuang].

To understand the pollution characteristics of aromatic compounds in Shijiazhuang, PM samples were collected day and night for 30 days from September 18 to October 17, 2016. Qualitative and quantitative analyses were conducted using gas chromatography-mass spectrometry (GC-MS). The results showed that total average concentration of aromatic compounds was 33.

[Analysis of Different Particle Sizes, Pollution Characteristics, and Sources of Atmospheric Aerosols During the Spring Dust Period in Beijing].

To understand the evolution of the physical and chemical properties of dust aerosols in the atmosphere, the concentrations and chemical compositions of differently sized particles were continuously observed and analyzed using an ion chromatograph and carbonaceous analyzer during the outbreak of dust in May 2017 in Beijing. The concentrations of total suspended particulate (TSP), water-soluble organic carbon (WSOC), elemental carbon (EC), OC, and water-soluble inorganic ions were (2237.59±681.

Evolution of aerosol chemistry in Xi'an during the spring dust storm periods: Implications for heterogeneous formation of secondary organic aerosols on the dust surface.

TSP and 9-stage size-segregated samples were simultaneously collected in Xi'an during the spring of 2013 and analyzed for organic aerosols (OA) on a molecular level. n-Alkanes were the dominant compound class during the whole campaign, followed by fatty acids. High molecular weight (HMW) n-alkanes and fatty acids dominated in the coarse mode particles (>1.

[The change of patients' psychosomatic symptoms after orthognathic surgery].

Purpose: To assess the change of patients' psychological status before and after orthognathic surgery.

Methods: The psychological status in 36 patients were assessed before and after orthognathic surgery using the SCL-90 questionnaire. The patients were allowed to evaluate the changes of mastication, facial aesthetics, pronunciation and function of temporomandibular joint subjectively through the questionnaire.

[Observation of size distribution of atmospheric OC/EC in Tangshan, China].

Atmospheric particulate matter pollution is serious in Tangshan, a heavy industrial city of North China. The annual average concentrations of PM1.1, PM2.

[Water-soluble inorganic salts in ambient aerosol particles in Tangshan].

To investigate the levels, seasonal variation and size distributions of water soluble inorganic components, samples were collected with an Andersen cascade sampler in Tangshan from Sep. 2010 to Aug. 2011, and were analyzed by IC.

[Pollution characteristics and source identification of atmospheric particulate matters n-alkanes in Baoding City].

Organic matter has been a very important component in the ambient particulate matter of big cities in China. In order to investigate the mass concentrations and sources of the organic matter which are adsorbed in ambient particulate matters in the industry cities of Hebei province, aerosol samples were collected with Anderson sampler during Sep. 2009 to Aug.

[Analysis on water-soluble inorganic ions in the atmospheric aerosol of Xinglong].

Size-segregated aerosol samples were collected using Andersen cascade sampler from Sep. 2009 to Aug. 2010 in Xinglong, a regional atmospheric background station.

[Chemical characteristics and sources of trace metals in precipitation collected from a typical industrial city in Northern China].

To investigate the chemical characteristics and possible sources of trace metals in precipitation of Tangshan, a typical industrial city in Northern China, precipitation samples were collected using an automated wet-only sampler for one year from December 2009 to November 2010 and subjected to chemical analysis using ICP-MS. The results showed that crustal elements (Ca, Mg, Na, K, Fe and Al) accounted for 97.72% of the total concentrations while heavy metals (Zn, Mn, Pb, Ba, Sb, Cu, Ni, As, V, Co and Se) only contributed 2.

[Chemical composition and mass closure of particulate matter in Beijing, Tianjin and Hebei megacities, Northern China].

To seek an efficient prevention and control method of regional atmospheric pollution in Jingjinji area, mass concentrations and size-resolved chemical composition of particulate matter were investigated at four urban sites and one background site from June 2009 to May 2010. The results show that the annual mean concentration of PM10 was 124, 141, 151 and 183 microg x m(-3) in Beijing, Tianjin, Tangshan and Baoding respectively, while the corresponding percentage of daily limit value exceedances was 29%, 36%, 39% and 52%, which is well above the maximum allowed limit of 150 microg x m(-3) (National Air Quality Stand II). As for PM2.

[Size distribution and characterization of EC and OC in aerosols during the Olympics of Beijing, China].

Samples of airborne PM with different size were collected by cascade impactor (Andersen) in Beijing during the Beijing Olympics. Organic carbon (OC) and elemental carbon (EC) in particles were determined by DRI Model 2001 A t carbon analyzer of USA. PM (56%), OC (55%) and EC (73%) were associated with the fine particle below 2.

[Laryngeal function preserving surgery in hypopharyngeal carcinoma].

Objective: To evaluate the preservation of laryngeal function hypopharyngeal cancer surgery clinical effectiveness and impact of prognostic factors.

Methods: A retrospective analysis in September 1974 - July 2003 treated 45 cases of hypopharyngeal cancer surgery retain the clinical treatment of laryngeal function effect. Among them there were 23 cases of original pyriform sinus cancer, 13 cases of post cricoid cancer and 9 cases of postero pharyngeal wall cancer.

[Pollution characteristics of n-alkanes in atmospheric fine particles during Spring Festival of 2007 in Beijing].

Research PM2.5 aerosols had been carried out with sampler of high-volume sampler during Spring Festival of 2007 in Beijing, and the concentrations of n-alkane in PM2.5 samples were determined via GC-MS.

[Pollution characteristic of PAHs in atmospheric particles during the Spring Festival of 2007 in Beijing].

Research on PM10, and PM2.5, aerosols had been carried out with sampler of large flow capacity during the Spring Festival of 2007 in Beijing, and the concentration of polycyclic aromatic hydrocarbons (PAHs) in PM2.5, samples were determined via GC-MS.

Distribution patterns of nitrobenzenes and polychlorinated biphenyls in water, suspended particulate matter and sediment from mid- and down-stream of the Yellow River (China).

Samples of water, suspended particulate matter (SPM) and sediment were collected from mid- and down-stream of the Yellow River. The distribution and concentration of 10 nitroaromatic compounds and polychlorinated biphenyls (PCBs) were extensively studied. The total concentration of 10 nitrobenzenes (SigmaNBs) varied from 0.