以去氢弯孢霉素NMR结构解析讲授本科生波谱分析课程

以去氢弯孢霉素核磁共振波谱(NMR)解析为例,讲授本科化学和药学相关专业波谱分析课程NMR解析。去氢弯孢霉素结构包含苯环、双键、酚羟基、羰基和酯基等常见基团,NMR信号几乎无重叠、辨识度高,非常适合作为核磁共振波谱结构解析中化学位移、耦合常数和二维核磁共振波谱的授课内容。

SOME SPECIAL SELF-SIMILAR SOLUTIONS FOR A MODEL OF INVISCID LIQUID-GAS TWO-PHASE FLOW

In this article,we are concerned with analytical solutions for a model of inviscid liquid-gas two-phase flow.On the basis of Yuen’s works[25,27–29]on self-similar solutions for compressible Euler equations,we present some special self-similar solutions for a model of inviscid liquid-gas two-phase flow in radial symmetry with and without rotation,and in elliptic symmetry without rotation.Some blowup phenomena and the global existence of the solutions obtained are classified.

Farnesyltransferase inhibitor lonafarnib suppresses respiratory syncytial virus infection by blocking conformational change of fusion glycoprotein

Respiratory syncytial virus(RSV)is the major cause of bronchiolitis and pneumonia in young children and the elderly.There are currently no approved RSV-specific therapeutic small molecules available.Using high-throughput antiviral screening,we identified an oral drug,the prenylation inhibitor lonafarnib,which showed potent inhibition of the RSV fusion process.Lonafarnib exhibited antiviral activity against both the RSV A and B genotypes and showed low cytotoxicity in HEp-2 and human primary bronchial epithelial cells(HBEC).Time-of-addition and pseudovirus assays demonstrated that lonafarnib inhibits RSV entry,but has farnesyltransferase-independent antiviral efficacy.Cryo-electron microscopy revealed that lonafarnib binds to a triple-symmetric pocket within the central cavity of the RSV F metastable pre-fusion conformation.Mutants at the RSV F sites interacting with lonafarnib showed resistance to lonafarnib but remained fully sensitive to the neutralizing monoclonal antibody palivizumab.Furthermore,lonafarnib dose-dependently reduced the replication of RSV in BALB/c mice.Collectively,lonafarnib could be a potential fusion inhibitor for RSV infection.

可压缩量子Navier-Stokes方程组光滑解的爆破

本文研究多维可压缩量子Navier-Stokes方程组Cauchy问题光滑解的爆破现象.不同于经典Navier-Stokes方程组光滑解的爆破结果,在一些初始值的合理限制下,本文证明对任意大于1的绝热指数,当黏性系数相对于Planck常数较小时,可压缩量子Navier-Stokes方程组光滑解在有限时刻爆破.

Existence of Classical Solutions to a Stationary Simplified Quantum Energy-Transport Model in 1-Dimensional Space

The existence of classical solutions to a stationary simplified quantum energytransport model for semiconductor devices in 1-dimensional space is proved.The model consists of a nonlinear elliptic third-order equation for the electron density,including a temperature derivative,an elliptic nonlinear heat equation for the electron temperature,and the Poisson equation for the electric potential.The proof is based on an exponential variable transformation and the Leray-Schauder fixed-point theorem.

Application of a quantitative ^1H NMR method for rapid extraction and determination of the content of paeonol in Cynanchum paniculatum

Cynanchum paniculatum(Bunge) Kitagawa is usually used as an herbal medicine for treating many diseases. Paeonol is the main active component, and its content is the key indicator for quality control of C. paniculatum. In the present study, we developed a rapid, accurate and precise method for quantitation of paeonol in C. paniculatum using 1 H NMR spectra. The deuterated solvent of methanol-d4 enabled satisfactory separation of the signals to be integrated in 1 H NMR spectrum. H-6(δ 7.78) of 1 H NMR spectrum of C. paniculatum was selected as the feature signal for quantitation, and trimesic acid(TMA) was selected as an internal standard. Validation of the quantitative method was performed in terms of linearity, specificity, repeatability and stability. This is the first time to report quantitative 1 H NMR(qHNMR) applied to determine the content of paeonol in C. paniculatum and showed a wider linearity range than the reported quantitation of paeonol in others. The simple extraction of paeonol from C. paniculatum was rapid and will prompt the application of the developed method. This work implied that qHNMR represented a feasible alternative to HPLC-based methods for quantitation of paeonol in C. paniculatum, and it was suitable for the quality control of C. paniculatum.

Variations in concentrations and bioavailability of heavy metals in rivers caused by water conservancy projects： Insights from water regulation of the Xiaolangdi Reservoir in the Yellow River

Water regulation of the Xiaolangdi Reservoir of the Yellow River was chosen as a case to investigate variations in concentrations and bioavailability of heavy metals caused by water conservancy projects in rivers. Water and suspended sediment（SPS） samples were collected at downstream sampling sites along the river during this period. Concentrations and speciation of Zn, Cr, Cu, Ni, and Pb in water and SPS samples were analyzed, and their bioaccumulation was studied with Daphnia magna. This study indicated that the exchangeable and carbonatebound fractions of heavy metals in SPS decreased along the studied stretch, and the dissolved heavy metal concentrations increased along the river with 1.6–15 folds. This is because sediment resuspension increased along the river during water regulation, giving rise to the increase of heavy metal release from SPS. The dissolved Zn, Cu, Ni, and Pb concentrations were significantly positively correlated with SPS concentrations, and their increase along the river was greater than Cr. The body burdens of heavy metals in D. magna exposed into samples collected from the reservoir outlet were 1.3–3.0 times lower than those from downstream stations, suggesting that the heavy metal bioavailability increased during water regulation.This should be considered in the reservoir operation.

The antioxidant activity and total phenolic and total flavonoid contents of Pyracantha fortuneana fruit can be improved by solid-state fermentation with Rhizopus oryzae and Penicillium commune

The fruits of Pyracantha fortuneana(Maxim.)Li were fermented with pure fungi to improve their antioxidant capacity.The antioxidant activities of fermented and non-fermented P.fortuneana fruits were estimated by 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS)radical scavenging activities,as well as ferric ion reducing antioxidant power(FRAP).The total phenolic content(TPC)and total flavonoid content(TFC)were also determined.Additionally,the changes caused by fermentation were characterized by proton nuclear magnetic resonance spectroscopy(1H NMR).The results showed that P.fortuneana fruits fermented with Rhizopus oryzae and Penicillium commune exhibited stronger antioxidant activity compared with the non-fermented material.Correlation analysis indicated that the increased activity might be ascribed to the improvement of TPC.Chemical characterization of 1H NMR implied that the increased TPC and antioxidant activity might be attributed to some of the phenolic and flavonoid glycosides hydrolyzed to new components during fermentation.The present study was the first report of the fermentation of P.fortuneana fruit with pure fungal strains and suggested that fermentation of P.fortuneana fruits with R.oryzae and P.commune was an effective alternative approach to increase antioxidant,and P.fortuneana fruit fermented by R.oryzae and P.commune might be the new alternative of natural antioxidants.

Antibiotics along an alpine river and in the receiving lake with a catchment dominated by grazing husbandry

The livestock breeding industries face overuse of antibiotics,which has been intensively studied in recent years.However,the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear.This study investigated the relationship of the occurrence and concentrations of antibi-otics between the Kaidu River and Bosten Lake in a typical alpine basin in China.Hot spots with antibiotic pollution source were explored.The antibiotic concentrations in river water and suspended sediment(SPS)were 2.20-99.4 ng/L and 1.03-176 ng/g.The dominant antibi-otics were tetracyclines,sulphacetamide,and ofloxacin in river water and sulfonamides,clarithromycin,roxithromycin,and ofloxacin in SPS.The apparent differences in pollution sources and landscapes in different reaches led to the obvious spatial patterns of antibiotics in the Kaidu River.Higher partition coefficient of antibiotic between SPS and water phases for sulfonamides than tetracyclines was because that tetracyclines strongly responded to clay contents while sulfonamides significantly responded to organic carbon contents in SPS.There were significant differences in detected antibiotic categories between the river and the lake.Fluoroquinolones(especially ciprofloxacin and enrofloxacin)were detected in the lake while sulphacetamide was only detected in the river.Therefore,the surrounding husbandry and aquaculture around the Bosten Lake was an important antibiotic pollution source in addition to inputs from the Kaidu River.This research suggested that alpine lakes could be an important sink of antibiotics in alpine dry regions,and thus impose greater threats to the aquatic ecosystem.