Series-Type Switched-Inductor Z-Source Inverter

To solve the disadvantages of the traditional Z-source inverter(ZSI),this paper investigates a series-type switched-inductor Z-source inverter(SSI-ZSI)topology.It not only preserves the advantages of the traditional ZSI,but also improves the voltage gain.On the condition of the same voltage gain,the capacitor voltage stress is reduced,the soft start characteristic can be achieved and the inverter can be immune to the damage of the inrush current.The circuit structure and operating principle are analyzed in detail;the simulation model and the experimental platform are built.The simulation and experimental results verify the rationality and superiority of the circuit topology.

An Algorithm of 0-1 Knapsack Problem Based on Economic Model

In order to optimize the knapsack problem further, this paper proposes an innovative model based on dynamic expectation efficiency, and establishes a new optimization algorithm of 0-1 knapsack problem after analysis and research. Through analyzing the study of 30 groups of 0-1 knapsack problem from discrete coefficient of the data, we can find that dynamic expectation model can solve the following two types of knapsack problem. Compared to artificial glowworm swam algorithm, the convergence speed of this algorithm is ten times as fast as that of artificial glowworm swam algorithm, and the storage space of this algorithm is one quarter that of artificial glowworm swam algorithm. To sum up, it can be widely used in practical problems.

Polyethylene imine functionalized porous carbon framework for selective nitrogen dioxide sensing with smartphone communication

Highly selective and remotely communicable nitrogen dioxide(NO_(2))sensing may contribute to future Internet of Things in environmental monitoring.However,room-temperature NO_(2)sensing materials such as carbon materials is still less than satisfactory due to their insensitive interaction with target gas.Here,polyethylene imine functionalized three-dimensional(3D)carbon framework(PEI/C framework)has been developed for enhanced selective NO_(2)sensing,via combined template synthesis and subsequent doping.Typically,the 3D PEI/C framework is observed porous shape with irregular coating.Beneficially,the response of C framework to NO_(2)increases while those of interfering gases decrease after being functionalized with PEI.Remarkably,the sensor prototypes show a 100 ppb-concentration detection limit at room temperature.Theoretically,such excellent NO_(2)sensing is attributed to the large specific surface ratio of porous 3D PEI/C framework,in which PEI serves as an active layer for target NO_(2),while a passivated one for interfering gases.Practically,such PEI/C framework sensor prototype is simulated for NO_(2)sensing device and communicated with a smartphone,showing great potential in future intelligent environmental monitoring.

Clinical antitumor application and pharmacological mechanisms of Dahuang Zhechong Pill

Cancer still has elevated morbidity and mortality,which undoubtedly impacts the life quality of affected individuals.Remarkable advances have been made in cancer therapy,although the toxicities of traditional therapies remain an obvious challenge.Dahuang Zhechong Pill(DHZCP),developed by Zhongjing Zhang in the Synopsis of the Golden Chamber,represents an effective anticancer traditional Chinese medicine(TCM).In this review,it was found that DHZCP is therapeutically utilized in liver,lung,gastric,pancreatic and other cancers in clinic.Pharmacological evidence showed that its anti-tumor mechanisms mainly involve induced cell cycle arrest,apoptosis and autophagy,as well as suppressed tumor cell proliferation,obstructed angiogenesis and metastasis,enhanced immunity,and reversal of multidrug resistance.The present review provides a solid basis for the clinical application of DHZCP and may promote the wide use of TCM in clinical antitumor application.

Iridium-Catalyzed Asymmetric Hydrogenation of Tetrasubstituted Exocyclic Olefins:An Efficient Access to Dexmethylphenidate

An Ir-catalyzed enantioselective hydrogenation of challenging tetrasubstituted exocyclic olefins is disclosed.This new catalytic system tolerates a broad substrate scope and affords valuable chiral cyclic β-amino esters possessing two vicinal stereocenters in high yields and excellent enantioselectivities and diastereoselectivities(up to 94% yield,96% ee,99:1 dr).Control experiments and deuterium-labeling reactions reveal an iminium hydrogenation mechanism upon Brønsted acid-promoted tautomerization of the C=C double bond to cycliciminium intermediates.Density functional theory calculations showcase that the excellent selectivities are derived from C-H…π interaction between the substrate and the chiral ligand.Application in gram-scale preparation of dexmethylphenidate with up to 1500 turnover number is also demonstrated,showing the promising potential of Ir-catalyzed enantioselective hydrogenation in drug synthesis.

Inventory and Spatial Distribution of Landslides Triggered by the 8th August 2017 M_W 6.5 Jiuzhaigou Earthquake, China

An accurate and detailed seismic landslide inventory is essential to better understand the landslide mechanism and susceptibility. The 8 th August 2017 MW 6.5 Jiuzhaigou Earthquake of China initiated a large number of coseismic landslides. The results of the post-seismic survey show the actual landslide number might be underestimated in previous publications. Coupled with field investigation and visual interpretation on high-resolution remote sensing images before and after the main shock, we established a detailed inventory of landslides triggered by the earthquake. Results show that this event caused at least 4 834 individual landslides with a total area of 9.64 km^2. They are concentrated in an elliptical area of 434 km^2, dominated by medium-and small-scale rock falls and debris slides. Statistics indicate that, except for slope aspect that seems not significantly correlated with the landsliding, these landslides are most common in the places with following features: elevation of 2 800–3 400 m, slope angle greater than 30o, slope positions of upper, middle and flat slopes, and Carboniferous limestone and dolomite. Besides, the landslide area percentage(LAP) and landslide number density(LND) values decrease with the increasing distance to river channels and roads, implying a positive correlation. Instead of centering around the epicenter, most of these coseismic landslides are distributed along the inferred seismogenic fault, which means that the seismogenic structure played a more important role than the location of the epicenter. Remarkable differences in landslide densities along the fault indicate the varied landslide susceptibility which may be attributed to other varied controls along the fault such as the rock mass strength. In sum, this study presents a more detailed inventory of the landslides triggered by the 2017 MW 6.5 Jiuzhaigou Earthquake, describes their distribution pattern and analyzes its control factors, which would be helpful to understand the genesis of the coseismic landslides and further study their long-term impact on the environment of the affected area.

Two Comparable Earthquakes Produced Greatly Different Coseismic Landslides:The 2015 Gorkha,Nepal and 2008 Wenchuan,China Events

The 2015 Gorkha Earthquake in Nepal and the 2008 Wenchuan Earthquake in China occurred at the south and southeast margins of the Tibetan Plateau, respectively. Both earthquakes had similar magnitudes of Mw 7.8 and 7.9, caused catastrophic loss of life and damage to property, and generated tens of thousands of landslides. Comparisons of pre-and post-quake satellite images supported by field investigations show that the Gorkha Earthquake triggered at least 2 064 large landslides （defined as covering an area ≥10 000 m2） over a -35 600 km2 region with a volume of （444-584）×10^6 （average 509×10^6） m3 and total area of 44.78×10^6 m2. In contrast, the Wenchuan Earthquake triggered 25 580 large landslides over a region of -44 000 km2 with a volume of （7 128-9 479）×10^6 （average 8 219×10^6） m3 and a total area of about 670.65×10^6 m2. Several controlling factors including topographic relief, slope steepness, and regional peak ground acceleration （PGA） were investigated to try to explain the great differences between the number, volume and area of the coseismic landslides associated with the two similar earthquakes. We found that the differences primarily arose from an unexpected factor, the dip angle of the seismogenic fault. This discovery should aid understanding the failure mechanisms of quake-triggered landslides, and suggests that more factors should be taken into consideration in estimating coseismic landslide volumes from earthquake magnitudes. KEY WORDS： Gorkha Earthquake, Wenchuan Earthquake, landslide, dip angle, seismogenic fault.

Detailed Inventory Mapping and Spatial Analyses to Landslides Induced by the 2013 Ms 6.6 Minxian Earthquake of China

On July 22, 2013, an earthquake （Ms 6.6） occurred in Minxian, Gansu Province of China, causing a large number of landslides. Based on high resolution remote sensing images before and after this event, we made the visual interpretation to these coseismic landslides, and prepared a detailed inventory. The inventory registers totally 6 478 landslides in the study area. Of them, 3 322 landslides are larger than 100 m2. Based on 5 m resolution DEM, these landslides were used to perform spatial analyses using landslide number density （LND） and landslide area percentage （LAP）. The results show that the highest LND and LAP values are in the elevation range of 2 300-2 500 m and steeper slopes. Slopes facing E, SE, S and SW directions, slopes with larger absolute curvature values, ridges, scopes of gravel beds of Late Pleistocene （Qp） and the VIII-degree seismic intensity are more prone to sliding with high LND and LAP values. The largest LND and LAP values are in the scopes of 0.08 and 0.24 g, respectively. According to landslide distribution, we infer that F2-2 branch of Lintan-Dangchang fault is the seismogenic fault. With the increasing distances to this branch fault and drainages, LND and LAP values tend to decrease.

Mutation of DELAYED GREENING1 impairs chloroplast RNA editing at elevated ambient temperature in Arabidopsis

Chloroplasts are important for plant growth and development.RNA editing in chloroplast converts cytidines(Cs)to uridine s(Us)at specific transcript positions and provides a correction mechanism to restore conserved codons or creates start or stop codons.However,the underlined molecular mechanism is not yet fully unders tood.In the present study,we identi fied a thermo-sensi tive mutantin leaf color 1(tst1)and found that TSL1 is allelic to DELAYED GREENING 1(DG1).The mis sense mutation of DG1 in tsl1 mutant confers a high temperature sensitivity and impaired chloroplast development at an elevated ambient temperature in Arabidopsis.Subsequent analysis showed that chloroplast RNA editing at seve ral sites including accD-2568,ndhD-2,and petL-5 is impaired in tsl1 mutant plants grown at an elevated temperature.DG1 interacts with MORF2 and other proteins such as DYW1 and DYW2 involved in chloroplast RNA editing.In vitro RNA electrophoretic mobility shift assay demonstrated that DG1 binds to RNA targets such as accD,ndhD,and petL.Thus,our results revealed that DG1 is important for maintaining chloroplast mRNA editing in Arabidopsis.

Landslides Triggered by the 3 August 2014 Ludian(China) Mw 6.2 Earthquake: An Updated Inventory and Analysis of Their Spatial Distribution

The 3 August 2014 Ludian, Yunnan, China Mw 6.2(Ms 6.5) earthquake triggered a large number of coseismic landslides. Based on pre-and post-quake high-resolution optical satellite images, this study established a new, complete and objective database of these landslides with field investigations. The updated inventory shows that this earthquake triggered at least 12 817 landslides with a total occupation area of 16.33 km2, covering a nearly circular area about 600 km2, which all exceed those in our previous work and other relevant studies. In addition, we used this database to examine the correlations of the landslides with topographic, geologic, and seismic factors. Results show that the landslides occurred mostly at places with slope gradients 10o–40o, showing an increase tendency with steeper slopes. Affected by the propagation direction of the earthquake rupture, the eastward-facing slopes are more prone to landsliding. The differences between the landslide susceptibility in different strata indicate that lithology is also an important controlling factor. The landslide density of the places with peak ground acceleration(PGA) greater than 0.16 g is obviously larger than those with PGA less than 0.16 g. Meanwhile, the greater the distance from the epicenter, the lower the susceptibility of landslides is. This study suggests that when using satellite images to create coseismic landslide inventories, it should meet certain conditions, including high resolution, whole coverage, and timely data collection. The correct criteria of coseismic landslide inventorying also should be followed. Such inventories can provide a reliable basis for hazard assessment of earthquake-triggered landslides and other quantitative studies.

Spatiotemporal dynamics of cell abundance,colony size and intracellular toxin concentrations of pelagic and benthic Microcystis in Lake Caohai,China

Lake Caohai has experienced extensive Microcystis blooms in recent years,and to improve its water quality,the local government carried out a series of water control measures.To better understand the dynamics of both pelagic and benthic Microcystis and their characteristics in Lake Caohai,we conducted a 1-year investigation from December 2015to December 2016 to gain a seasonal outlook on the distribution and dynamics of cell abundance,colony size and intracellular microcystins(MCs)of Microcystis.The results indicated that the Microcystis bloom occupied primarily the northeastern region and then moved gradually from lakeshore to lake center.The perennial southwesterly winds and the water inflow from northeast to southwest in Lake Caohai determined the spatiotemporal distribution of pelagic Microcystis.Benthic Microcystis was mainly distributed in the northeastern region in summer,occupied the lake center in autumn and then occupied the southeastern region in winter,determined by the sedimentation of pelagic Microcystis and the death of benthic Microcystis.Small colonies(20-60μm)overwintered more easily in both water column and sediment.The concentrations of intracellular toxin of benthic Microcystis were observed to be significantly higher than those of pelagic Microcystis.This might be because Microcystis synthesized large amount of MCs to acclimate to an unfavorable benthic environment.This knowledge on the dynamics of Microcystis expands our understanding of mechanisms underpinning the formation of Microcystis blooms.

Study on the effects of the different polar group of EPA-enriched phospholipids on the proliferation and apoptosis in 95D cells

EPA-enriched phosphatidylcholine(EPA-PC)and EPA-enriched phosphatidylethanolamine(EPA-PE)are newly identified marine phospholipids.The polar group of phospholipids is known to influence EPA-phospholipid activity.However,the differences in anti-tumor effects between EPA-PC and EPA-PE have not been reported.In this study,we evaluated the effects of two forms of EPA on the proliferation and apoptosis in the lung-cancer cell line 95D as well as possible molecular mechanisms.Our results showed that EPA-PC effectively inhibited proliferative activity and promoted apoptosis of 95D cells in a dose-dependent manner,while EPA-PE had no effect on cell proliferation,although it slightly promoted apoptosis.Western blot results showed that EPA-PC and EPA-PE upregulated the expression of PPARy,RXRoc,and PTEN,and downregulated the PI3K/AKT signaling pathway.Furthermore,EPA-PC and EPA-PE induced the expression of the pro-apoptotic gene,Bax,and reduced the expression of the anti-apoptotic gene,Bcl-xl.Additionally,EPA-PC and EPA-PE promoted the release of cytochrome c and activated the apoptotic enzyme-cleaved caspase-3.These data suggest that the anti-tumor effect of EPA-phospholipids may be exerted via a PPARy-related mechanism.EPA-PC was more efficacious as compared to EPA-PE,which might be due to the different polar groups of phospholipids.