Quantitative estimation of enzymatic released specific oligosaccharides from Hericium erinaceus polysaccharides using CE-LIF

Polysaccharides exhibit multiple pharmacological activities which are closely related to their structural features.Therefore,quantitatively quality control of polysaccharides based on their chemical charac-teristics is important for their application in biomedical and functional food sciences.However,poly-saccharides are mixed macromolecular compounds that are difficult to isolate and lack standards,making them challenging to quantify directly.In this study,we proposed an improved saccharide mapping method based on the release of specific oligosaccharides for the assessment of Hericium eri-naceus polysaccharides from laboratory cultured and different regions of China.Briefly,a polysaccharide from H.erinaceus was digested by b-(1-3)-glucanase,and the released specific oligosaccharides were labeled with 8-aminopyrene-1,3,6-trisulfonic-acid(APTS)and separated by using micellar electrokinetic chromatography(MEKC)coupled with laser induced fluorescence(LIF),and quantitatively estimated.MEKC presented higher resolution compared to polysaccharide analysis using carbohydrate gel elec-trophoresis(PACE),and provided great peak capacity between oligosaccharides with polymerization degree of 2(DP2)and polymerization degree of 6(DP6)in a dextran ladder separation.The results of high performance size exclusion chromatography coupled with multi-angle laser light scattering and refractive index detector(HPSEC-MALLS-RI)showed that 12 h was sufficient for complete digestion of polysaccharides from H.erinaceus.Laminaritriose(DP3)was used as an internal standard for quantifi-cation of all the oligosaccharides.The calibration curve for DP3 showed a good linear regression(R2>0.9988).The limit of detection(LOD)and limit of quantification(LOQ)values were 0.05 mg/mL and 0.2 mg/mL,respectively.The recovery for DP3 was 87.32(±0.03)%in the three independent injections.To sum up,this proposed method is helpful for improving the quality control of polysaccharides from H.erinaceus as well as other materials.

Fast saccharide mapping method for quality consistency evaluation of commercial xylooligosaccharides collected in China

Due to the extensive use of xylooligosaccharides(XOS)as functional food ingredients,many inferior goods and even adulterants are generally found in the market,which may pose a health hazard to certain populations.Chromatography method such as high-performance liquid chromatography(HPLC)and high-performance thin-layer chromatography(HPTLC)is traditionally applied for the quality analysis of XOS.However,it is time consuming due to the prolonged separation and pre-or post-derivatization procedure.In this study,a fast saccharide mapping method based on matrix-assisted laser desorption/time-of-flight mass spectrometry(MALDI-TOF-MS)was developed for the quality consistency analysis of 22 batches of XOS collected from different manufacturers in China.The time needed for saccharides analysis using MALDI-MS was less than 30 min for one plate,at least 6 times faster than that by the traditional HPTLC chromatography method.In addition,MALDI-MS possessed higher resolution for XOS with DP4-DP7 based on the difference of m/z,which is hardly separated using HPTLC.The results showed that XOS were present only in samples XY01-XY11,samples XY12-XY14 only consisted of hex oligosaccharides,and samples XY15-XY22 were free of oligosaccharides.These indicate that the quality consistency of XOS products in the China market was poor,which should be carefully investigated.

数字普惠金融背景下的小额信贷与农户收入

与传统小额信贷相比,以网络平台小额信贷为代表的数字普惠金融不但可以分散风险、降低信息成本,而且可以缓解资金供给不足的困境,因而在小额信贷领域备受期待。本文利用公益性网络借贷平台——宜农贷开展的追踪调查数据,实证考察了宜农贷平台借贷对农户收入的影响。基于倾向得分匹配基础上的双重差分法(PSMDID)分析表明:宜农贷平台借贷促进了农户人均纯收入的提高,且主要是通过提高农户的农业类收入实现。进一步研究发现,宜农贷平台借贷对农户人均纯收入的提高作用与农户人均纯收入水平之间呈现U型关系。因此,本文建议,在处于脱贫攻坚战关键期和加快乡村振兴的当下,政府可以通过政策支持引导以网络平台为媒介的小额信贷来支持贫困地区农村发展,进一步扩大返贫力量和资源。

Optimization of microwave-assisted extraction of bioactive alkaloids from lotus plumule using response surface methodology

In this work,a fast and efficient microwave-assisted extraction(MAE) method was developed to extract main bioactive alkaloids from lotus plumue.To optimize MAE conditions,three main factors were selected using univariate approach experiments,and then central composite design(CCD).The optimal extraction conditions were as follows:methanol concentration of 65%,microwave power of 200 W,and extraction time of 260 s.A high performance liquid chromatography–diode array detector(HPLC–DAD) method was established to quantitatively analyze these phytochemicals in different lotus plumule samples and in different part of lotus.Chromatographic separation was carried out on an Agilent Zorbax Extend-C_(18) column(4.6 mm×150 mm,3.5 μm).Gradient elution was applied with the mobile phase constituted with 0.1% triethylamine in water(A)and acetonitrile(B):40%-70% B at 0-8 min,70%-100% B at 8–9 min,100% B for 2 min,and then equilibrated with 40% B for 2 min.

Current-Induced Magnetic Switching in an L1_(0) FePt Single Layer with Large Perpendicular Anisotropy Through Spin–Orbit Torque

In this study,current-induced partial magnetization-based switching was realized through the spin–orbit torque(SOT)in single-layer L1_(0) FePt with a perpendicular anisotropy(K_(u⊥))of 1.19×10^(7) erg·cm^(-3)(1 erg·cm^(-3)=0.1 J·m^(-3)),and its corresponding SOT efficiency(βDL)was 8×10^(-6) Oe·(A·cm^(-2))^(-1)(1 Oe=79.57747 A·m^(-1)),which is several times higher than that of the traditional Ta/CoFeB/MgO structure reported in past work.The SOT in the FePt films originated from the structural inversion asymmetry in the FePt films since the dislocations and defects were inhomogeneously distributed within the samples.Furthermore,the FePt grown on MgO with a granular structure had a larger effective SOT field and effi-ciency than that grown on SrTiO_(3)(STO)with a continuous structure.The SOT efficiency was found to be considerably dependent on not only the sputtering temperature-induced chemical ordering but also the lattice mismatch-induced evolution of the microstructure.Our findings can provide a useful means of efficiently electrically controlling a magnetic bit that is highly thermally stable via SOT.

Analysis of Cordyceps by multi-column liquid chromatography

Cordyceps is a famous traditional Chinese medicine(TCM) that has been used in China for hundreds of years.In the present study a multi-column liquid chromatography(MC-LC) system was developed for the qualitative analysis of macromolecules and micromolecules in Cordyceps.The MC-LC system includes a size exclusion pre-column,a size exclusion column(SEC) and a reversed phase column(RP) which were controlled by column-switching valves.The sample was separated by the size exclusion pre-column into two fractions(macromolecules and micromolecules).These fractions were further separated on SEC and RP columns,respectively.A diode array detector(DAD) and a mass spectrometer(MS) were used to detect the components.This MC-LC method was utilized for analysis of Cordyceps samples.Two macromolecular peaks and 15 micromolecular peaks were found in Cordyceps,and 11 of the micromolecular peaks were identified as adenosine-5'-monophosphate(AMP),phenylalanine,uridine,hypoxanthine,inosine,guanine,guanosine,deoxyadenosine-5'-monophosphate(dAMP),adenosine,adenine and cordycepin(or its isomer).This method is useful for quality control of Cordyceps.

Clinical features of 162 fatal cases of COVID-19:a multi-center retrospective study

Background:The coronavirus disease 2019(COVID-19)has affected approximately 2 million individuals worldwide;however,data regarding fatal cases have been limited.Objective:To report the clinical features of 162 fatal cases of COVID-19 from 5 hospitals in Wuhan between December 30,2019 and March 12,2020.Methods:The demographic data,signs and symptoms,clinical course,comorbidities,laboratory findings,computed tomographic(CT)scans,treatments,and complications of the patients with fatal cases were retrieved from electronic medical records.Results:The median patient age was 69.5(interquartile range:63.0–77.25)years,and 80%of the patients were over 61 years.A total of 112(69.1%)patients were men.Hypertension(45.1%)was the most common comorbidity,while 59(36.4%)patients had no comorbidity.At admission,131(81.9%)patients had severe or critical COVID-19,whereas 39(18.1%)patients with hypertension or chronic lung disease had moderate COVID-19.In total,126(77.8%)patients received antiviral treatment,while 132(81.5%)patients received glucocorticoid treatment.A total of 116(71.6%)patients were admitted to the intensive care unit(ICU),and 137(85.1%)patients received mechanical ventilation.Most patients received mechanical ventilation before ICU admission.Approximately 93.2%of the patients developed respiratory failure or acute respiratory distress syndrome.There were no significant differences in the inhospital survival time among the hospitals(P=0.14).Conclusion:Young patients with moderate COVID-19 without comorbidity at admission could also develop fatal outcomes.The in-hospital survival time of the fatal cases was similar among the hospitals of different levels in Wuhan.

Free radical scavenging activity of Eagle tea and their flavonoids

In this study,an online HPLC-DAD-MS coupled with 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)diammonium salt(A BTS)assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components.Twenty-three chromatographic peaks were detected,and nineteen components had free radical scavenging activity.Among them,eight compounds were identified as flavonoids(hyperin,isoquercitrin,quercitrin,quercetin,kaempferol),catechins,chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.

Effect of Migration on Children's Self-esteem in Rural China

China＇s rapid economic growth has been facilitated by its large volume of rural to urban migration. China ＇s projected future development, especially increasing urbanization, implies that such migration will further intensify. However, migration does not come without cost. There are concerns about the potential negative impacts of migration on children＇s care, education, and, in particular, the self-esteem of children left behind in villages where one or both parents have out-migrated to cities. In this paper, we employ unique survey data collected from Shaanxi Province, where more than 4700 ninth grade students from 36 rural junior high schools in five counties were surveyed in late 2011. The results show that having both parents migrate into cities significantly reduced children ＂s self-esteem. The effects are also gender sensitive. Girls that had a father or both parents who had out-migrated were inclined to have lower self-esteem than boys. Moreover, our study findings indicate that parental migration decreased children ＂s self-esteem more for individuals with initial low self-esteem.