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A radical‐induced dichloromethylation and concomitant 1,2‐aryl migration of allylic alcohols with CHCl3 is developed for the construction of γ,γ‐dichloroketones in moderate to good yields. We found that, for the para‐substituted unsymmetrical substrates, the more electron‐deficient aryl group migrates preferentially over the more electron‐rich aryl group. Moreover, chlorocyclopropanes could be obtained from allyl alcohols in one‐pot manner through radical‐addition/1,2‐aryl migration/nucleophilic substitution. [ABSTRACT FROM AUTHOR]

A radical‐induced dichloromethylation and concomitant 1,2‐aryl migration of allylic alcohols with CHCl3 is developed for the construction of γ,γ‐dichloroketones in moderate to good yields. We found that, for the para‐substituted unsymmetrical substrates, the more electron‐deficient aryl group migrates preferentially over the more electron‐rich aryl group. Moreover, chlorocyclopropanes could be obtained from allyl alcohols in one‐pot manner through radical‐addition/1,2‐aryl migration/nucleophilic substitution. [ABSTRACT FROM AUTHOR]

Using potentially best available rainfall data sets for the entire country of Japan (spatial scales of 1‐ and 20‐km), we analyze the 1–24 hr and city‐scale (1–400 km2) extreme rainfalls for both current (2006–2020) and future periods (2081–2109) at 1.5 K global warming scenario, complementing previous work that focuses on either coarse spatial and temporal scales or other warming scenarios (e.g., RCP and 2 K warming scenarios). A peak‐over‐threshold (POT)‐based approach is applied to compute areal reduction factor (ARF) for subsequently establishing intensity‐duration‐area‐frequency (IDAF) curves. Our results reveal that ARF values generally decrease with increasing area size and increase with longer duration and are affected by multiple underlying physical phenomena. Moreover, we find a greater increase in the rainfall intensities for shorter durations and higher return periods, ranging from 9.4% (1‐hr) to 6.2% (24‐hr), averaged for all return periods and 8.3% (25‐year) to 7.3% (2‐year), averaged for all rainfall durations. Spatially, extreme rainfall intensities are projected to increase by 8.9% in northern Japan (albeit with a less intense rainfall intensity in the current period), which is greater than the rest of the country (6.8%), underscoring the need to focus more on infrastructure designs in northern Japan. The projected IDAF curves further display an increase in the frequency of extreme events at city‐scale, for example, 25‐year extreme rainfall events in 2006–2020 would likely be 5‐10‐year events in 2081–2109. Our results with the state‐of‐the‐art data and implementable approach can be utilized for policymaking to reduce the warming‐induced risks in Japan and beyond. Key Points: For the first time, we analyze the city‐scale and sub‐daily extreme rainfall for the entire country of Japan by using high‐quality data setsAreal reduction factor values generally decrease with increasing area size and increase with longer duration and are affected by multiple physical phenomenaUnder 1.5 K warming, extreme rainfall will increase more for shorter durations and higher return periods, especially in northern Japan [ABSTRACT FROM AUTHOR]

The development of agricultural robots and the promotion of agricultural production automation are important means to alleviate the shortage of agricultural labor. Fruit and vegetable detection is a prerequisite for accurate harvesting by robots. It directly determines the efficiency and quality of harvesting operations. In order to meet the requirements of target positioning and recognition of tomato harvesting robots, this paper studies tomato recognition technology based on YOLOv3 convolutional neural network algorithm. And the tomato detection process of the YOLOv3 model is presented. The YOLOv3 model training dataset is constructed based on greenhouse tomato plants. The test results show that the model based on the YOLOv3 convolutional neural network has a better detection effect. [ABSTRACT FROM AUTHOR]

In this paper, a reconfigurable double‐sided inductor‐capacitor‐capacitor (LCC)‐based data transfer method for wireless power transfer (WPT) system is proposed. The power and the data are, respectively, transferred through the orthogonal decoupled inductive links, and thus, the interference between the power transfer link and the data transfer link can be eliminated. Dual‐resonant frequency is used to exchange data in the binary frequency‐shift keying (2FSK) modulation. The performance of the reconfigurable LCC compensation topology is explored, and the design method is presented to improve the data transfer rate and to guarantee the similar data transfer characteristics under the two different frequencies. Thus, a stable data transfer can be guaranteed irrespective of the data type. The power transfer link and data transfer link are, separately, analyzed. Together with the well‐designed parameters, 512 W power with 115.2 kbps transfer rate half‐duplex communication is obtained, and the direct current–direct current (DC–DC) efficiency reaches 80.44%. [ABSTRACT FROM AUTHOR]

To investigate the relationship among summer atmospheric boundary layer (ABL) over the Taklimakan Desert (TD), its land surface parameters and large scale meteorological field, the Urumqi Institute of Desert Meteorology of China Meteorological Administration conducted a comprehensive observation of boundary layer in Tazhong, the hinterland of TD from July 1 to 31, 2016. The correlations between the ABL height and surface sensible heat, latent heat, air temperature, turbulent kinetic energy (TKE) and buoyancy term are analyzed by using the observed GPS sounding data, the surface layer micro meteorological data in the hinterland of the TD and ERA5 reanalysis data so as to study the correlation of the ABL height and Eurasian circulation field. The research results indicate: (1) The height of summer ABL over the TD does not fully correspond with the variation tendency of surface sensible heat flux. In addition to surface sensible heat, large scale advection and residual mixed layer (RML) are also crucial factor influencing ABL. (2) The surface TKE over the TD is consistent with ABL height variation, with the correlation coefficient of 0.62. Hence the equation of ABL height and TKE is expressed as: Y = 1609.2X4 – 12,828X3 + 35,617X2 –39,514X + 15,858. (3) When the ABL height over the TD is quite high, 500 hPa altitude in Xinjiang is mostly controlled by anticyclone circulation, and the easterly low level jet (LLJ) tends to be formed at 850 hPa the next night. (4) The high correlation areas of summer ABL height over the TD and Eurasian temperature field are Xinjiang and Balkash Lake region. Significant positive correlation is identified between the ABL height and the temperature field at 850, 700, and 500 hPa of the above regions. The maximum correlation coefficient reaches 0.7. The study deepens the understanding of the relationship among the ABL process over the TD, land surface parameters and Eurasian circulation. [ABSTRACT FROM AUTHOR]

A novel dynamic adaptive unstructured mesh (DAUM) algorithm is proposed to solve incompressible multi‐object relative motion (MORM). The DAUM algorithm, consisting of exponential function deformation, adaptive edge swapping, and area Laplace smoothing, can greatly improve dynamic mesh robustness and perfectly overcome mesh skewness. The core of DAUM is the adaptive edge swapping inspired by Delaunay triangulation, which is distinguished from traditional edge swapping. The adaptive edge swapping can fully consider the relationship of neighbor elements only using Delaunay triangulation. Meanwhile, the implementation and reliability of adaptive edge swapping are better than the traditional edge swapping method due to eliminating the interference of the non‐convex polygon, so more code remedies can be avoided. Using the DAUM, none of the vertices is inserted or deleted so that the manipulation of the dynamic mesh is easily implemented and maintains computational efficiency in the process of mesh motion. Three representative geometries are used to assess the performance of the DAUM in MORM. To systematically analyze the advantages of DAUM, two relatively moving cylinders have been numerically investigated in incompressible flow. The inline force and lift force profiles on two cylinders are obtained and analyzed by using the flow field information. Three interaction stages are divided based on the parameter G and the interactional intensity of two inner anticlockwise vortices is considered as the division criteria. At the running process of the DAUM algorithm, the dynamic mesh quality is well controlled and remains in the high‐quality range based on the aspect ratio (AR) criterion. The results indicate that the proposed DAUM algorithm can properly solve the difficulties caused by MORM, especially for period oscillation motion. [ABSTRACT FROM AUTHOR]

An efficient Tf2O‐mediated regioselective C(sp2)−H sulfenylation of enaminones has been described. Methyl sulfoxides are employed as sulfur sources to react with different types of enaminones under mild reaction conditions, providing a straightforward approach for the synthesis of β‐amino sulfides in up to 97% yield via one‐pot manner. Moreover, this sulfenylation proceeded smoothly with oxidant‐free and metal‐free. [ABSTRACT FROM AUTHOR]

Dual windings parallel (DWP) coils are often used in high‐power wireless charging applications to reduce current stress and internal resistance. Due to the inconsistent self‐inductance and strong coupling of the two windings, the advantages of the DWP coils cannot be fully utilized. In particular, the current stresses of the two windings are different, which will cause one of the stress to exceed the limit, and the temperature rise is too high. The reason for the current imbalance in the two windings is analysed in this work, and a distributed capacitor compensation method is proposed to balance the current stress in the two windings. Finally, a WPT system with the DWP transmitting coil was built as an example to demonstrate the effectiveness of the proposed method. The experimental results show that the current ratio in two windings decreased from 1.70 to 1.05 after using the proposed compensation method. [ABSTRACT FROM AUTHOR]

The effects of Ti addition on microstructure and the associated electrochemical properties of 22Cr‐5Ni duplex stainless steel were evaluated using X‐ray diffraction, X‐ray electron probe microanalysis, electron backscattered diffraction, scanning Kelvin probe force microscopy, scanning electron microscopy–energy‐dispersive X‐ray spectroscopy, electrochemical techniques, and X‐ray photoelectron spectroscopy. The results indicated that the addition of a minor amount of Ti refined the grains, improved the pitting potential, and lowered passive current densities remarkably. However, excessive content could cause an imbalance of phase proportion of ferrite and austenite phases and precipitation of the coarse TiN particles. The films on the base and Ti‐containing alloy have a similar chemical composition, but the addition of Ti enriched the chromium in the passive film. In particular, the ratio of Cr2O3 and Mo6+ increased, which helped to form a comparatively homogeneous and stable passive film on the duplex stainless steel. [ABSTRACT FROM AUTHOR]

Rectal cancer is a common malignant tumour and the progression is highly affected by the tumour microenvironment (TME). This study intended to assess the relationship between TME and prognosis, and explore prognostic genes of rectal cancer. The gene expression profile of rectal cancer was obtained from TCGA and immune/stromal scores were calculated by Estimation of Stromal and Immune cells in Malignant Tumors using Expression data (ESTIMATE) algorithm. The correlation between immune/stromal scores and survival time as well as clinical characteristics were evaluated. Differentially expressed genes (DEGs) were identified according to the stromal/immune scores, and the functional enrichment analyses were conducted to explore functions and pathways of DEGs. The survival analyses were conducted to clarify the DEGs with prognostic value, and the protein‐protein interaction (PPI) network was performed to explore the interrelation of prognostic DEGs. Finally, we validated prognostic DEGs using data from the Gene Expression Omnibus (GEO) database by PrognoScan, and we verified these genes at the protein levels using the Human Protein Atlas (HPA) databases. We downloaded gene expression profiles of 83 rectal cancer patients from The Cancer Genome Atlas (TCGA) database. The Kaplan‐Meier plot demonstrated that low‐immune score was associated with worse clinical outcome (P =.034), metastasis (M1 vs. M0, P =.031) and lymphatic invasion (+ vs. ‐, P <.001). A total of 540 genes were screened as DEGs with 539 up‐regulated genes and 1 down‐regulated gene. In addition, 60 DEGs were identified associated with overall survival. Functional enrichment analyses and PPI networks showed that the DEGs are mainly participated in immune process, and cytokine‐cytokine receptor interaction. Finally, 19 prognostic genes were verified by GSE17536 and GSE17537 from GEO, and five genes (ADAM23, ARHGAP20, ICOS, IRF4,MMRN1) were significantly different in tumour tissues compared with normal tissues at the protein level. In summary, our study demonstrated the associations between TME and prognosis as well as clinical characteristics of rectal cancer. Moreover, we explored and verified microenvironment‐related genes, which may be the potential key prognostic genes of rectal cancer. Further clinical samples and functional studies are needed to validate this finding. [ABSTRACT FROM AUTHOR]

To provide guidance for the use of reanalysis data in the Central Taklimakan Desert (CTD), five reanalysis products are evaluated based on the radiosonde data obtained from two field experiments during summer for the first time in the CTD, including the European Center for Medium‐Range Weather Forecasts (ECMWF) Reanalysis version 5 (ERA5), ECMWF Reanalysis‐Interim (ERA‐Interim), Japanese 55‐years Reanalysis (JRA55), Modern‐Era Retrospective Analysis for Research and Applications version 2 (MERRA2), and the National Centers for Environmental Prediction‐Department of Energy Reanalysis version 2 (NCEP2). The results show that reanalysis temperature (T), specific humidity (Q), geopotential height (GPH), and wind field (U and V components) are consistent with the radiosonde observations in terms of the vertical distribution. In general, ERA5 has the best performance in the CTD during the study period, followed closely by ERA‐Interim. However, NCEP2 produces the largest error. The errors of all the reanalysis data show significant diurnal variations, and the diurnal variations differ from each other. Moreover, the results indicate that the reanalysis datasets have the largest deviation at 850 hPa (near the ground), which means that in the desert region complex interactions may exist between the land surface and the atmosphere. Therefore, more attention should be paid to the description of complex interactions between land and atmosphere over the moving‐sand desert region in the numerical models. Key Points: Five reanalysis products are evaluated based on the radiosonde data obtained from the Central Taklimakan Desert (CTD)The ERA5 reanalysis product has the best performance over the CTD, compared to other datasetsThe largest deviation at 850 hPa (near the ground) means complicated interactions may exist between the land surface and the atmosphere in the desert region [ABSTRACT FROM AUTHOR]

An efficient CAN‐mediated C−C bond formation in the oxidative reactions of xanthenes with enaminones under mild reaction conditions are described. A variety of 9H‐xanthene‐9‐ylidene aldehydes could be synthesized in up to 90% yield via one‐pot manner with good functional group compatibility, which achieved the simultaneous construction of carbon‐carbon double bond and carbon‐oxygen double bond. [ABSTRACT FROM AUTHOR]

Anatomical analysis of liver region is an essential and key step for liver‐related disease diagnosis and treatment. One of the challenging issues is to annotate the functional regions of liver automatically or semi‐ automatically by analyzing Computed Tomography (CT) images. The present study developed a complete liver annotation system with an improved vessel‐skeletonization method is proposed for CT images. In the first step, an automatic level set method and a customized region‐growing method are applied to extract the liver region including vessels and tumors. Next, a modified iterative thinning method is developed to obtain the geometric structure of liver vessels and mark a vessel skeleton. The three‐dimensional information is transformed into a tree data structure for storage. Based on the branch distribution of portal vein skeleton, a model‐based method with a modified nearest neighbor segment approximation (NNSA) algorithm is adopted for the functional liver anatomy. Three experiments involving five 64‐row liver CT datasets are performed. The accuracies of segmentation and annotation results were validated by an experienced doctor. Compared with different methods, our proposed vessel skeletonization method can simultaneously preserve the connectivity of the vasculature topology and generate the skeleton in a shorter time. Furthermore, our proposed annotation system can provide both visual and measurable information of livers. These experimental results demonstrate the usefulness and effectiveness of our proposed method. Our liver annotation system is helpful to evaluate the function of liver system and support diagnosis of liver disease. [ABSTRACT FROM AUTHOR]

Discontinuous current mode (DCM) with high‐frequency operation can be an effective way to reduce the volume of inductors for low‐power grid‐tied inverter applications. Unlike the controllers designed for continuous current mode operations, current controllers for DCM are required to address their nonlinear characteristics. A feed‐forward controller can be a good choice for the current control of the grid‐tied inverters operated in DCM. However, distortions in the output current cannot be eliminated, and they can be more severe if devices with large output capacitance are applied. Two harmonic current reduction strategies, namely a partial feedback path and an improved modulation, are proposed to reduce the low‐ and high‐order harmonics for single‐phase grid‐tied inverters operated in DCM. The proposed strategies are discussed and verified by a laboratory prototype in some experiments. It is indicated that the proposed modulation can mitigate the influence of device parasitic capacitance on current distortion and expand the device selections. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed intermolecular annulation and arylation cascade between internal alkynes and o‐triazole bromobenzenes was developed, delivering to various polysubstituted [1,2,3]triazolo[1,5‐a]quinolines. Broad substrate scope, great functional group tolerance and simple operation of this transformation, hold great synthetic potential for the rapid construction of fused N‐heterocycles with biologically activity. [ABSTRACT FROM AUTHOR]

To investigate the features of the extremely deep atmospheric boundary layer (ABL) over the Taklimakan Desert (TD) and its influence, this paper utilizes sounding data obtained from a month‐long intensive field campaign carried out in July 2016 over the TD to study the structure of the 5,000‐m‐depth ABL over the desert and the features of its temporal and spatial variations. The differences and causes of the regional circulation are analyzed for both the deep ABL and shallow ABL over the TD. We show that (1) deep ABLs occurred frequently in the hinterland and the surrounding areas of the TD in July 2016. The numbers of days when the ABL height reached 4,000 m at Tazhong, Minfeng, Korla, Ruoqiang, and Kashgar are 8, 9, 5, 4, and 2, respectively, and the numbers of days when the ABL height exceeded 3,000 m at the above locations are 20, 22, 13, 15, and 5, respectively. (2) The ABL height reached 5,000 m over the TD on 1 July 2016. The diurnal variation of the ABL appears in such a manner that it develops and intensifies gradually from southeast to northwest direction. The middle of the desert witnesses large values of ABL heights. The ABL height in the desert is obviously higher than those in the surrounding oases and in the northern part of Xinjiang. (3) On 1 July 2016, a deep ABL process is accompanied by a strong easterly low‐level jet on the following night, which triggers significant air accumulation and dynamic convergence in the lower‐level atmosphere over the middle and west of the TD, thus intensifying the divergence and anticyclonic circulation at the 500‐hPa middle‐level atmosphere. (4) The influence of the deep ABL process on 1 July on the regional circulation mainly occurs below 400 hPa, while its influence is relatively small above 400 hPa. This type of influence is also regional, as it mainly occurs over the TD and its surrounding areas. This study enriches the understanding of the deep ABL process over the TD and its influence. Key Points: The maximum height of the atmospheric boundary layer (ABL) exceed 5,000 m over the Taklimakan DesertThe deep ABL process is accompanied by a strong easterly low‐level jet (LLJ) on the following nightThe LLJ triggers the convergence upward movement in the lower atmosphere and intensifies the divergence and anticyclonic circulation at 500 hPa [ABSTRACT FROM AUTHOR]

A gold (I)‐catalyzed reaction of enyne‐ethers to rapidly construct oxa‐bridged compounds via a tandem 1,2‐acyloxy migration/intramolecular oxonium formation/1,2‐rearrangement process was reported. The reaction was shown to be robust with a wide range of substitution patterns tolerated to provide the corresponding oxygen‐containing bridged products in good to excellent yields. [ABSTRACT FROM AUTHOR]

The effects of solution annealing temperature and isothermal time on the phase composition evolution and corrosion behavior were investigated by employing energy dispersive spectrometry, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, and Mott–Schottky analysis. The pit morphologies were observed by a digital VHX‐5000 with a visible 3D microscopy system. The highest corrosion resistance and most stable passive films were obtained for specimen solution annealing at 1075 °C. Additionally, the solution time had a significant influence on the microstructure evolution and corrosion resistance of the duplex stainless steel. The largest impedance values were exhibited, revealing the best stability with a superior corrosion resistance of the films. The depth and size of pits that occurred on austenite were smaller than those on ferrite. The phase proportion on the microstructure and redistribution of the alloying elements caused by duplex interdiffusion solution annealing simultaneously affected the density of defects and the stability of the passive film, which determined the corrosion resistance. However, the semiconductor properties of the passive films were not affected. [ABSTRACT FROM AUTHOR]

A conformal array sensor suitable for partial discharge (PD) detection of electrical equipment was designed which displays multiple characteristics including compatibility with the surface of any carrier without affecting the performance of the carrier. Taking a cylindrical conformal array as an example, the simulation model was given and the array flow pattern of the cylindrical conformal array sensor was determined. Based on the Euler transform, the algorithm of multiple signal classification (MUSIC) was improved. An algorithm of array signal direction finding suitable for conformal array sensors was proposed and its performance under different signal‐to‐noise ratios and different array elements was simulated. The improved algorithm and conformal array sensor were used to simulate and test the PD signal. The results show that the algorithm and the conformal array sensor are suitable for PD detection of electrical equipment. [ABSTRACT FROM AUTHOR]

Abstract: A catalytic [1,3] O‐to‐C rearrangement from enyne‐ethers was developed for the rapid synthesis of diverse bridged bicyclic systems. In this reaction, a vinyl oxonium intermediate, generated in situ from enyne‐ether, was the precursor for the [1,3] O‐to‐C rearrangement. This versatile protocol represents the first example of catalytic [1,3] O‐to‐C rearrangement based on ring‐expansion strategy, enabling efficient access to bridged bicyclic scaffolds. [ABSTRACT FROM AUTHOR]

Abstract: We present a silver‐catalyzed reaction of acceptor‐enynals with alkynes to assemble tetracyclic framework of fluorenols efficiently, in which the reaction was proposed to proceed through an unfavorable 6‐endo‐dig cyclization, followed by a tandem [4+2] cycloaddition/Friedel–Crafts reaction. The reaction could be conducted in one pot for diaryl alkynes substrates. For terminal aryl alkyne or arylalkyl alkyne substrates, the Friedel–Crafts reaction has to be performed in the absence of alkynes. The control reactions demonstrated that there was competition between [Ag]⋅⋅⋅alkyne and [Ag]⋅⋅⋅O=CR2. [ABSTRACT FROM AUTHOR]

A cascade reaction of donor-acceptor cyclopropanes with enynals to construct indanone-fused cyclopentanes via a sequential hydrolysis/Knoevenagel condensation/[3+2] cycloaddition is reported. The desired indanone-fused cyclopentanes were obtained in good yields. This method features mild reaction conditions and broad substrate scope, which render it very appealing to chemists for the synthesis of complex molecules containing an indanone-fused cyclopentane moiety. Moreover, the products could be further converted into compounds with different functional groups through the well-known transformations. [ABSTRACT FROM AUTHOR]

Yb3+-doped LuAG laser ceramics with different Yb3+-doping concentrations were successfully fabricated by nonaqueous tape casting method and vacuum sintering technology. XRD patterns and SEM morphologies of the ceramics were presented. The optical in-line transmittance of the Yb-doped LuAG ceramics was about 83% at 1030 nm. The fluorescence lifetime of annealed and unannealed ceramic samples was compared. From the spectroscopic properties, it can be seen that the ceramics had a large emission cross section of 2.9 3 10-20 cm² with a FWHM of about 7.2 nm at 1030 nm. Under 100% population inversion, the maximum gain coefficient was estimated to be 12.4 cm-1 at 1030 nm. With a fiber-coupled diode laser as pump source, CW laser at 1030 nm was demonstrated and the maximum output power of 338.9 mW was achieved with a slop efficiency of 19%. A tuning range from 1028 to 1036 nm was obtained. [ABSTRACT FROM AUTHOR]

In Arabidopsis thaliana and Oryza sativa, the cytochrome P450 (CYP) 714 protein family represents a unique group of CYP monooxygenase, which functions as a shoot-specific regulator in plant development through gibberellin deactivation. Here, we report the functional characterizations of PtCYP714A3, an OsCYP714D1/Eui homologue from Populus trichocarpa. PtCYP714A3 was ubiquitously expressed with the highest transcript level in cambium-phloem tissues, and was greatly induced by salt and osmotic stress in poplar. Subcellular localization analyses indicated that PtCYP714A3-YFP fusion protein was targeted to endoplasmic reticulum (ER). Expression of PtCYP714A3 in the rice eui mutant could rescue its excessive-shoot-growth phenotype. Ectopic expression of PtCYP714A3 in rice led to semi-dwarfed phenotype with promoted tillering and reduced seed size. Transgenic lines which showed significant expression of PtCYP714A3 also accumulated lower GA level than did the wild-type (WT) plants. The expression of some GA biosynthesis genes was significantly suppressed in these transgenic plants. Furthermore, transgenic rice plants exhibited enhanced tolerance to salt and maintained more Na+ in both shoot and root tissues under salinity stress. All these results not only suggest a crucial role of PtCYP714A3 in shoot responses to salt toxicity in rice, but also provide a molecular basis for genetic engineering of salt-tolerant crops. [ABSTRACT FROM AUTHOR]

A systematic investigation of ZnCl2-catalyzed reactions of enynals with alkenes has been undertaken. Structurally unique propeller-like products could be obtained under mild conditions. Cyclic o-quinodimethanes ( o-QDMs) are generated through [4+2] cycloaddition between enynals and alkenes. Both electron-poor and electron-rich dienophiles could be used to trap the active intermediate through [4+2] cycloaddition. But [1,5]-H shift products could also be observed when electron-rich alkenes were used as dienophile. DFT calculations were performed to understand the reaction mechanism. A competition between the [4+2] cycloaddition and [1,5]-H shift was proposed for the transformation of cyclic o-QDMs. The selectivity could be affected by the properties of the substrates. [ABSTRACT FROM AUTHOR]

ABSTRACT The Urumqi Institute of Desert Meteorology of China Meteorological Administration carried out a scientific experiment to detect the clear-sky atmospheric boundary layer by using a wind-profiling radar and L-band radar sounding system in the hinterland and southern margin of the Taklamakan Desert in the summer of 2010 and 2011. Based on wind profile and radiosonde data collected from this experiment, this paper analyses the vertical structure features of the clear-sky daytime convective boundary layer and night-time stable boundary layer in the hinterland and southern margin of the desert, and compared the result with the boundary layer features in the Tibetan Plateau and the Dunhuang region in Gansu. The results show that: (1) the summer clear-sky convective boundary layers in the hinterland and southern margin of the Taklamakan Desert can develop thickly. The mixing layer can reach a maxiumum thickness of 3700 m, above which a significant entrainment layer exists with average thickness about 500 m. The maximum thickness of the convective boundary layer can exceed 4000 m. (2) A temperature inversion phenomenon is found to exist remarkably over the summer clear-sky nights in the hinterland and southern margin of the desert. The thickness of the night stable boundary layer is about 400-600 m, but the residual layer above it generally can reach a thickness of more than 3000 m. (3) An atmospheric boundary layer with supernormal thickness under the clear summer sky is a phenomenon of arid regions in Northwest China. [ABSTRACT FROM AUTHOR]

A one-pot tandem process involving hydrolysis, Knoevenagel condensation, Michael addition, and Conia-ene (HKMC) reactions has been developed for the rapid synthesis of indanone-fused 2-methylene tetrahydrofurans from the reaction of enynals and propynols. In this process, two rings and four bonds are generated with 100 % atom-economy and high step-efficiency. The resulting tetrahydrofurans were readily oxidized into α-methylene γ-lactones, which are one of the most important substructures in natural and bioactive compounds. [ABSTRACT FROM AUTHOR]

ABSTRACT A rapid and highly selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for determination of polygalasaponin F (PF) in rat plasma was developed and validated. The chromatographic separation was achieved on a reverse-phase Zorbax SB-C18 column (150 × 4.6 mm, 5 µm), using 2 m m ammonium acetate (pH adjusted to 6.0 with acetic acid) and acetonitrile (25:75, v/v) as a mobile phase at 30 °C. MS/MS detection was performed using an electrospray ionization operating in positive ion multiple reaction monitoring mode by monitoring the ion transitions from m/z 1091.5 → 471.2 (PF) and m/z 700.4 → 235.4 (internal standard), respectively. The calibration curve showed a good linearity in the concentration range 0.0544-13.6 µg/mL, with a limit of quantification of 0.0544 µg/mL. The intra- and inter-day precisions were <9.7% in rat plasma. The method was validated as per US Food and Drug Administration guidelines and successfully applied to pharmacokinetic study of PF in rats. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Stearoyl-acyl carrier protein desaturase ( SACPD) activity is essential for production of the major unsaturated fatty acids ( UFAs) in plant lipids. We report here the characterization of three SACPD genes from Nicotiana benthamiana, Nb SACPD- A, - B, and - C. All three genes share high similarity to At SSI2/ FAB2 (Suppressor of Salicylic acid-Insensitivity2/Fatty Acid Biosynthesis2), the primary SACPD isoform in Arabidopsis. Knocking down the expression of individual or combinations of Nb SACPDs by an artificial micro RNA approach resulted in significantly reduced accumulation of 18 C UFAs and elevated levels of 18:0- FA (Fatty acids) in leaves, indicating that all three genes participated in fatty acid desaturation. The triple knockdown ( KD) plants displayed severe growth phenotypes, including spontaneous cell death and dwarfing. While no vegetative morphologic abnormality was observed in Nb SACPD-A, - B, or - C KD plants, strikingly, Nb SACPD-C KD plants produced small fruits with aborted ovules. Reciprocal crosses with wild-type and Nb SACPD-C KD plants revealed that knocking down Nb SACPD-C expression caused female, but not male, sterility. Furthermore, arrested ovule development and significantly altered lipid composition in ovaries were observed in Nb SACPD- C KD plants, consistent with the predominant Nb SACPD- C expression in ovules. The ovule development defect was fully complemented by coexpressing an ami RNA-resistant Nb SACPD-C variant in the Nb SACPD-C KD background, further supporting a specific requirement for Nb SACPD-C in female fertility. Our results thus indicated that Nb SACPD-C plays a critical role maintaining membrane lipid composition in ovule development for female fertility in N. benthamiana, complementing and extending prior understanding on the well-demonstrated roles of SACPDs in biotic and abiotic stresses. [ABSTRACT FROM AUTHOR]

The chemoselectivity in the reaction of 2-diazo-3-oxo-3-phenylpropanal ( 1) with aldehydes and ketones in the presence of Et3N was investigated. The results indicate that 1 reacts with aromatic aldehydes with weak electron-donating substituents and cyclic ketones under formation of 6-phenyl-4 H-1,3-dioxin-4-one derivatives. However, it reacts with aromatic aldehydes with electron-withdrawing substituents to yield 1,3-diaryl-3-hydroxypropan-1-ones, accompanied by chalcone derivatives in some cases. It did not react with linear ketones, aliphatic aldehydes, and aromatic aldehydes with strong electron-donating substituents. A mechanism for the formation of 1,3-diaryl-3-hydroxypropan-1-ones and chalcone derivatives is proposed. We also tried to react 1 with other unsaturated compounds, including various olefins and nitriles, and cumulated unsaturated compounds, such as N, N′-dialkylcarbodiimines, phenyl isocyanate, isothiocyanate, and CS2. Only with N, N′-dialkylcarbodiimines, the expected cycloaddition took place. [ABSTRACT FROM AUTHOR]

Title compound (I) reacts with cyclic ketones (II) and aromatic aldehydes with weak electron-donating substituents (IV) to generate 1,3-dioxin-4-one derivatives (III) and (V), respectively. [ABSTRACT FROM AUTHOR]