格隆溴铵立体异构体杂质的毛细管电泳测定——推荐一个药物分析实验

推荐了一个药物分析实验——手性毛细管电泳分析药物格隆溴铵的立体异构体。实验内容包括:环糊精手性选择剂的选择、毛细管电泳分离条件的优化、标准曲线的绘制等。本实验从药物分析的角度,重点介绍毛细管电泳分析方法、手性分离的原理及药物立体异构体杂质分析的重要性。建议在应用化学、药学及制药工程等专业开设。

Experimental investigation of characteristics of instability evolution in a centrifugal compressor

The stable range of operation for the centrifugal compressor significantly influences the dynamic,economic,and environment-friendly characteristics of power systems.A deep understand-ing of the characteristics of instability evolution is necessary to improve the compressor stability.A centrifugal compressor equipped with a vaneless diffuser is experimentally investigated using high-response static-pressure measurements.The results obtained indicate that three typical rotational-speed ranges exist based on the different instability evolution characteristics,which reveals the var-ious impeller–diffuser matching behaviors over the entire speed range.At low-speed ranges((40%–75%)N_(max),N_(max)is the maximum rotational speed),the compressor exhibits stable,Rotating Insta-bility(RI),impeller stall(diffuser stall),and surge modes.The impeller stall mode is induced by RI and propagates downstream,resulting in the diffuser stall and compressor surge modes.In the medium-speed range((75%–85%)N_(max)),the compressor exhibits stable,diffuser stall,RI,and surge modes.In the high-speed range((85%–100%)N_(max)),the compressor exhibits stable,diffuser stall,and surge modes.The dominant instability position is shifted from the impeller to the diffuser as the rotational speed increases.Both the impeller and diffuser stall present an irregular sawtooth static-pressure wave and exhibit broadband frequency spectrum patterns.

East Asian paleoclimate change in the Weihe Basin (central China) since the middle Eocene revealed by clay mineral analysis

Obtaining a continuous sedimentary record of Cenozoic East Asian paleoclimate change is key to understand the origin,evolution and driving mechanism of the East Asian monsoon and climate change.Based on the continuous Cenozoic fluvial and lacustrine sedimentary sequence in the Weihe Basin,central China,we carried out research on the content and crystal parameters of clay minerals.The paleoclimate change since the middle Eocene was reconstructed accordingly.The results show that smectite and illite are the dominant clay minerals in fluvial-lacustrine sediments of Weihe Basin.The crystallinity of illite,the chemical index of illite,the ratio of smectite to illite and chlorite decrease gradually,which indicates that chemical weathering in the Weihe River watershed stepwise weakened since the middle Eocene,under the background of a semi-arid and semi-humid climate.The formation of palygorskite may be affected by a weak diagenesis.In this case,the content of smectite and the illite crystallinity caused by the weathering in the corresponding period may be actually higher than that of the current,which indicates that the climate in the Weihe Basin region was relatively warm and humid from the middle Eocene to Pliocene.With the decrease of Cenozoic global temperature and the continuous accumulation of sediments,the intensity of chemical weathering in the Weihe Basin gradually weakened,and the East Asian monsoon climate gradually evolved until becoming dry in the Quaternary.Evidence from clay minerals also indicates that the aridification in the Weihe Basin from the late Eocene to the Oligocene may be a response to the global cooling event at the Eocene-Oligocene transition.

Cadmium accumulation and tolerance of two castor cultivars in relation to antioxidant systems

To investigate the effects of Cd on tolerance and antioxidant activities of castor, two different castor（Ricinus communis L.） cultivars（Zibo No. 5 and Zibo No. 8） were used for a hydroponic experiment（0, 1 and 2 mg/L Cd） and a pot experiment using Cd-contaminated soil（34 mg/kg） with the addition of ethylenedinitrilotetraacetic acid（EDTA）. The results indicated that there were significant differences between the two cultivars with respect to Cd uptake in shoots（113–248 mg/kg for Zibo No. 5 and 130–288 mg/kg Zibo No. 8）, biomass tolerance indexes（64.9%–74.6% for Zibo No. 5 and 80.1%–90.9% for Zibo No. 8） in the hydroponic experiment and survival rates（0% for Zibo No. 5 and 100% for Zibo No. 8）determined by the addition of EDTA in the pot experiment, suggesting that Zibo No. 8 has higher tolerance than Zibo No. 5. Moreover, the castor cultivars have low bioconcentration factors（4.80% for Zibo No. 5 and 5.43% for Zibo No. 8） and low translocation factors（〈1%）.Consequently, Zibo No. 8 can participate in Cd phytostabilization in highly Cd-polluted areas. The results indicated that glutathione（GSH） as a non-enzymatic antioxidant, and antioxidant enzymes including superoxide dismutase（SOD）, catalase（CAT） and guaiacol peroxidase（GPX）, were cultivar- and dose-dependent. The higher tolerance of Zibo No. 8compared with Zibo No. 5 can be attributed to the higher GSH levels in the root and higher GPX activity in the leaf.

Drainage evolution in intermontane basins at the Qinling-Daba Mountains

River capture is of great significance to landform evolution and hominine migration.In the Qinling-Daba Mountains,there is a viewpoint that Jialing River captured Hanjiang River,but this is still controversial.In this paper,we discuss the drainage evolution processes in intermountain basins at the Qinling-Daba Mountains based on a combination of detrital zircon UPb geochronology and geomorphic indexes.We suggest that the Hanjiang River gradually captured the Jialing River from east to west,accompanied by the evolution of the ancient Yangtze River.In terms of geomorphic evidences,wide valleys did not match with discharge,and a series of wind gaps developed in the Shiquan-Ankang basin.In addition,the valley shapes and width-toheight ratios(Vf)indicate two possible rapid incisions.The hypsometric integrals(HI)reflect that the landform gradually changes from the old stage to the youth stage from west to east.Theχvalues show that the drainage divide is moving to the side of the Yuehe River,and the Yuehe River is gradually shrinking.According to the sedimentary records,the zircon U-Pb age distributions indicate the provenance change.The high-altitude terraces show three age peaks(200–250,400–505,and 700–900 Ma),with the dominant Indosinian age peak(200–250 Ma),while the modern fluvial sediments only show a single peak of Jinning(700–900 Ma).These data show that there are two major river captures:(1)The ancient Hanjiang River cut through the regional compression ridge,and then captured the Hanzhong Basin river system(a part of the ancient Jialing river system)from east to west,and(2)The southern tributary captured the trunk with the uplift of the divide in the Shiquan-Ankang Basin,forming the modern drainage pattern in the upper Hanjiang River.The activities of the regional strike-slip fault,and the associated compression uplift played a key role in the river captures,the drainage evolution,and related landforms in the Shiquan-Ankang basin.In addition,it is shown that the evolution of the upper tributary basins lagged behind the response of the trunk channel to the tectonic activities and river captures.The interconnected wide valleys caused by river capture may have provided convenient geomorphological conditions for human migration into the Qinling-Daba Mountains along those river valleys.

Washing out heavy metals from contaminated soils from an iron and steel smelting site

Washing is a promising method for separating contaminants bound to the particles of soil ex-situ by chemical mobilization. Laboratory batch washing experi- ments were conducted using deionized water and varying concentrations of oxalic acid, citric acid, tartaric acid, acetic acid, hydrochloric acid and ethylenediaminetetra acetic acid （EDTA） to assess the efficiency of using these chemicals as washing agents and to clean up heavy metals from two heavily polluted soils from an iron and streel smelting site. The toxicity reduction index and remediation costs were analyzed, and the results showed that the soils were polluted with Cd, Pb and Zn. Hydrochloric acid and EDTA were more efficient than the other washing agents in the remediation of the test soils. The maximum total toxicity reduction index showed that 0.5 mol·L^-1 hydro- chloric acid could achieve the remediation with the lowest costs.

Preparation of Durable Emitter of Electrospray Mass Spectrometry by Covalently Coating the Fused-Silica Capillary Tip with Carbon-Nanotube Sol-Gel Composite Material

A simple approach for the preparation of emitter of electrospray ionization mass spectrometry by covalently coating the fused-silica capillary tip with the conductive carbon-nanotube sol-gel composite material(CNTSCM)is described.The CNTSCM was prepared by dispersing single-walled carbon nanotubes in the sol composed of a mixture of 3-glycidoxypropyltrimethoxysilane and 3-aminopropyltrimethoxysilane,and ethanol.The long-term sta-bility of the prepared ESI emitters was demonstrated by at least 180 h of continuous use.Signal intensity obtained by the prepared emitter was mass-flux sensitive when the flow rate was lower than 500 nL/min,while the signal in-tensity performed a concentration dependence when the flow rate was in the range of 500-800 nL/min.The use-fulness of such a prepared emitter was demonstrated by the analysis of various types of samples such as organic small molecular drugs,oligosaccharide,peptide,and protein.

Evaluation and prospect of scientific research capacity ranking for community healthcare centres in China

The National Health and Family Planning Commission of the People's Republic of China has proposed to improve the medical capacity of general practitioners and the establishment of general practice in recent health reform.For the first time,the ability to conduct scientific research was included in this reform,which demands community healthcare centres(CHCs)to strengthen their research capacity.The evaluation of community scientific research capacity has become an important endeavour to promote the implementation of research in CHCs.Since 2016,our research team has been working on an evaluation system and has published the scientific research capacity ranking for the top 100 CHCs in China.The latest released ranking of scientific research capacities of China CHCs has aroused great attention in the country.