Cu/Chiral Phosphoric Acid-Catalyzed Asymmetric Three-Component Radical-Initiated 1,2-Dicarbofunctionalization of Alkenes.

An asymmetric intermolecular, three-component radical-initiated dicarbofunctionalization of 1,1-diarylalkenes with diverse carbon-centered radical precursors and electron-rich heteroaromatics by a copper(I) and chiral phosphoric acid cooperative catalysis strategy has been developed, providing straightforward access to chiral triarylmethanes bearing quaternary all-carbon stereocenters with high efficiency as well as excellent chemo- and enantioselectivity. The key to success is not only the introduction of a sterically demanding chiral phosphoric acid to favor radical difunctionalization over the otherwise remarkable side reactions but also the in situ generation of carbocation intermediates from benzylic radical to realize asymmetric induction with the aid of a removable hydroxy directing group via cooperative interactions with chiral phosphate. Density functional theory calculations elucidated the critical chiral environment created by the hydrogen-bonding and ion-pair interactions between the chiral phosphoric acid catalyst and substrates, which leads to the enantioselective C-C bond formation.

Direct Photocatalytic Synthesis of Medium-Sized Lactams by C-C Bond Cleavage.

Reported is a novel two-step ring-expansion strategy for expeditious synthesis of all ring sizes of synthetically challenging (hetero)aryl-fused medium-sized lactams from readily available 5-8-membered cyclic ketones. This step-economic approach features a remote radical (hetero)aryl migration from C to N under visible-light conditions. Broad substrate scope, good functional-group tolerance, high efficiency, and mild reaction conditions make this procedure very attractive. In addition, this method also provides expedient access to 13-15-membered macrolactams upon an additional one-step manipulation. Mechanistic studies indicate that the reaction involves an amidyl radical and is promoted by acid.

[Characteristics of Spatial and Temporal Changes in Carbon Stocks in the Middle and Upper Reaches of the Huaihe River Basin and Future Multi-scenario Simulation Prediction].

The Huaihe River Basin is located in the north-south climate transition zone of China. The change of carbon storage in this area is of great significance for predicting the future ecological protection, mitigating climate change, and maintaining sustainable development of the Huaihe River Basin. The middle and upper reaches of Huaihe River Basin （above Bengbu station） were taken as the research area. Based on the land use data from 1980 to 2020, the PLUS model was used to simulate and predict the land use types in the study area from 2030 to 2100 under the scenarios of SSP1-2.6, SSP2-4.5, SSP5-8.5, and the continuation of land use status. The carbon module in the InVEST model was used to simulate and predict the carbon storage from 1980 to 2020 and the carbon storage from 2030 to 2100 under various scenarios, and the spatial and temporal changes of carbon storage in the middle and upper reaches of the Huaihe River Basin were compared and analyzed. The results showed that： ① From 1980 to 2020, the basin showed a decrease in both cultivated land and grassland,and the area of forest,water, construction, and unused land all increased, among which the area of cultivated land continued to decrease, with a total decrease of 4 699 km2 in 40 a. Construction land continued to increase, with a total increase of 4 592 km2 in 40 a. ② The carbon storage in the basin showed a downward trend, with a total reduction of 1.05×107 t from 1980 to 2020. ③ In the four scenarios, the area of each land type had different degrees of change, and that of the SSP1-2.6 scenario was relatively small out of the four scenarios. ④ Compared with the carbon storage in 2020, the carbon storage in the SSP1-2.6 scenario increased by 8.7×104 t, the carbon storage in the SSP2-4.5 scenario decreased by 1.42×107 t, the carbon storage in the SSP5-8.5 scenario decreased by 1.34×107 t, and the carbon storage in the current continuation scenario decreased by 1.22×107 t. The study can provide a scientific basis for land use structure management and ecological protection in the middle and upper reaches of the Huaihe River Basin （above Bengbu station） in the future.

[Evaluation of total suspended matter based on spectral classification].

Total suspended matter concentration is one of the important parameters of water component. Traditional retrieval model ignored the difference of case 2 water which has complex optical properties. In the present study, we developed a method of water classification based on optical classification using HJ-1 multispectral data. We divided the water into two types and developed a retrieval model suitable for different water type. The results indicate: (1) the accuracy of retrieved results based on spectral classification has been improved; (2) exponential model reflects the relationship between suspended sediment concentration and retrieved factor and is better for type I water, while linear model is better for type II water.

A Potential Novel Indication for Preventing Thromboembolism in Patients with Atrial Arrhythmias: Remodeling of the Left Atrium.

OBJECTIVE: Thrombosis in patients with atrial arrhythmias might be associated with remodeling of the left atrium (LA). We aimed to describe this relationship and identify a novel factor, in addition to the CHA2DS2-VASc score, to guide therapeutic strategies for preventing thromboembolism in the hope of improving the prognosis for such patients. METHODS: Patients diagnosed with atrial arrhythmias and who met our inclusion criteria were enrolled in this study. Various clinical parameters were recorded; diameters reflecting remodeling of the LA were measured and thrombosis was diagnosed by enhanced CT. RESULTS: Totally, 192 patients were enrolled in the study. The overall prevalence of left atrial thrombosis was 8.3%. Patients with persistent atrial fibrillation exhibited the highest anteroposterior diameter of the LA (45.1±7.2 mm) and prevalence of thrombosis (15.6%). An anteroposterior LA diameter of ≥50 mm was a strong independent impact risk factor for thrombosis (OR=10.1, 95%CI: 2.8-36.9, P<0.001). The prevalence of LA thrombosis in patients with and without anteroposterior LA diameter of ≥50 mm was 25.8% and 5.0%, respectively. CONCLUSION: Marked remodeling of the LA characterized by an anteroposterior LA diameter of ≥50 mm is a strong independent risk factor of thrombosis, and should be considered for the prevention of thromboembolism through various strategies.

[Spatial Differences and Influencing Factors of Denitrification and ANAMMOX Rates in Spring and Summer in Lake Taihu].

Denitrification and ANAMMOX are the main nitrogen removal processes in lakes, which are of great significance for maintaining the nitrogen balance. Lake Taihu is a large, shallow lake. There are great spatial and temporal differences in the nutrient levels and algal blooms, which will affect the rates of denitrification and ANAMMOX. In order to understand the spatial and temporal variations in the denitrification and ANAMMOX rates and their influencing factors in Lake Taihu, undisturbed sediment cores were collected from Meiliang Bay, Gonghu Bay, Zhushan Bay, Dapukou Bay, Xukou Bay, and the center of Lake Taihu in the spring and summer of 2020. The results showed that the spatial distribution of the denitrification and ANAMMOX rates varied greatly in different areas of Lake Taihu in spring. The denitrification and ANAMMOX rates were (27.74±8.45)-(142.43±35.54) µmol·(m2·h)-1 and (2.35±1.06)-(17.95±8.66) µmol·(m2·h)-1, respectively. The contribution of ANAMMOX to nitrogen removal was relatively low, ranging from (7.82±1.71)% to (11.20±1.53)%. In summer, the denitrification and ANAMMOX rates were (165.68±62.14) µmol·(m2·h)-1 and (33.56±10.66) µmol·(m2·h)-1, respectively. The nitrogen removal rates were relatively low in other areas where the denitrification and ANAMMOX rates were (25.47±10.46)-(42.50±16.46) µmol·(m2·h)-1 and (2.65±0.94)-(5.95±2.65) µmol·(m2·h)-1, respectively. The contribution of ANAMMOX to nitrogen removal was (13.62±1.95)%-(7.24±1.78)%. The denitrification rate in summer was generally lower than that in spring, while the ANAMMOX rate did not decrease significantly compared with that in spring. The statistical analysis showed that the denitrification and ANAMMOX rates were significantly correlated with the substrate nitrogen concentration (P<0.01), which indicated that the nitrogen concentration was the main factor causing the difference in the nitrogen removal rates in different lake regions. In addition, there was a significant positive correlation between the contribution rate of ANAMMOX and the concentration of chlorophyll-a (P<0.05), thereby indicating that cyanobacteria blooms have a great influence on the change in the contribution of ANAMMOX to nitrogen removal.

[Changes in Algal Particles and Their Water Quality Effects in the Outflow River of Taihu Lake].

Connected rivers are a common engineering method to ensure the ecological health of urban water. However, for the lakes with serious cyanobacteria blooms, the algal particles are carried by the outflow of the lake and will have a significant impact on water quality. The location at which the Liangxi river meets Meiliang Bay of Lake Taihu was selected to explore the influence of the eutrophic lake on the connected rivers, and high-frequency monitoring was conducted in summer for three consecutive years to analyze the changes in the flux of cyanobacterial bloom particles in rivers and their impact on river water quality. The results show that:① The improvement of the algal cyanobacteria bloom in Meiliang Bay and the operation of the pressure-controlled algae well at the entrance of the river significantly reduced the concentration of chlorophyll a and the flux of algae particles in the Liangxi River. The average value of the concentration of chlorophyll a and the flux of algae particles in the river in summer 2019 were 54.34 µg·L-1 and 84.7 t·d-1, respectively, and significantly lower than those of 2017; ② Water diversion had a significant effect on improving the water quality of the receiving water. Except for DTP, the nitrogen and phosphorus concentrations of the remaining forms of the Liangxi River showed a downward trend from 2017 to 2019, indicating that the water quality of the Liangxi river improved after water transfer; ③ A large amount of cyanobacterial blooms entering the channel significantly increased the particulate nitrogen and phosphorus content of the water. From 2017 to 2019, the nitrogen and phosphorus in the Liangxi River were mainly PN and PP, accounting for 62.5% and 70.8% of TN and TP, respectively; ④ The water quality of the Beijing-Hangzhou Grand Canal and other connected rivers has not been affected by the algal particles in Meiliang Bay. In August 2019, the chlorophyll a content in the canal water decreased by 65% compared with that of June, indicating that cyanobacterial bloom particles have not accumulated in the Grand Canal; ⑤ On the premise that the cyanobacteria bloom in the lake has not been effectively improved, the algae particles carried by the water diversion will have an impact on the water quality and landscape of the local reach connecting the river.

[Reconstruction of Water Hyperspectral Remote Sensing Reflectance Based on Sparse Representation and Its Application].

Multispectral satellite sensors have several limitations with respect to capturing the target's spectral information due to their band setting and number of bands. The hyperspectral reconstruction technique is an effective method to obtain hyperspectral information from multispectral data. In this study, we propose a hyperspectral reconstruction algorithm based on the sparse representation of water remote sensing reflectance. The proposed algorithm was validated for five ocean color sensors (Sentinel-2A MSI, MERIS, MODIS Aqua, GOCI, and ⅦRS) using in situ measured above-water remote sensing reflectance. The mean absolute percentage error (MAPE) and root mean square error (RMSE) of the reconstructed and measured spectra for five ocean color sensors were less than 10% and 0.005 sr-1, respectively. Compared with the spectra reconstruction algorithm based on multi-variable linear regression, the proposed algorithm can obtain the features of complex water remote sensing reflectance without using in situ-measured reflectance for algorithm tuning. In addition, the accuracy of the proposed algorithm is better than the spectra reconstruction algorithm based on multi-variable linear regression. Two spectra reconstruction algorithms were applied to five ocean color sensors to test the applicability of the remotely estimated water constituent concentration. The statistical results for the reconstructed spectral factors and in situ water constituent concentration suggest that the reconstructed reflectance derived by the proposed algorithm has a performance similar to that of in situ-measured hyperspectral reflectance. The reconstructed reflectance derived by the proposed algorithm performs better than the spectra reconstruction algorithm based on multi-variable linear regression. Finally, the proposed algorithm was applied to GOCI data to remotely estimate the chlorophyll-a and total suspended matter concentrations. The accuracy of the water constituent concentration estimated from reconstructed images is better than that using original multispectral images. For the estimation of the chlorophyll-a concentration, the MAPE improved from 80.6% to 51.5% and the RMSE improved from 12.175 µg·L-1 to 7.125 µg·L-1. For the estimation of total suspended matter, the MAPE improved from 19.1% to 18.8% and the RMSE improved from 29.048 mg·L-1 to 28.596 mg·L-1.

Oximinotrifluoromethylation of unactivated alkenes under ambient conditions.

An efficient protocol for oximinotrifluoromethylation of unactivated alkenes was developed via trifluoromethyl radical-induced intramolecular remote oximino migration under mild reaction conditions, providing a wide range of ß-trifluoromethylated oximes. Other fluoroalkyl radicals were also applicable for this transformation. This method provided access to synthetically challenging medium-sized ring scaffolds and the 6,7,5-fused lactam skeleton.

[A Three Band Chlorophyll-a Concentration Estimation Model Based on GOCI Imagery].

A GOCI-based three band model is proposed for chlorophyll-a concentration estimation based on the classical three band model. The model was built based on 289 in-situ measured chlorophyll-a concentration and hyperspectral spectrums-simulated GOCI spectrums, and was compared with MERIS-based three band model and GOCI band ratio model. At last, the model was validated using several GOCI images and an independent in-situ sampling dataset. The results showed that: (1) For the current dataset, the ratio of aph (680) and aph (660) was relatively stable. (2) The GOCI-based three band algorithm had a similar performance with MERIS-based three band algorithm in the modeling dataset. The R2 value of the GOCI-based three band model was 0. 809, which was a little lower than that of the MERIS-based three band model (R2 = 0. 820), but was obviously higher than that of GOCI band ratio model (R2 = 0. 450). (3) The performance of GOCI-based three band model in the validation dataset was similar with that in the modeling dataset, which was close to that of the MERIS-based three band model, and significantly better than that of GOCI band ratio model. (4) The GOCI image data validation indicated that GOCI band ratio model would clearly underestimate chlorophyll-a concentration in Taihu Lake. The spatial difference of chlorophyll-a concentration that yielded by the band ratio model was not clear. Compared with the widely used band ratio algorithm, the GOCI-based three band algorithm has higher stability, better accuracy, and stronger potential in application.

[Cloning and characterization of D-113 gene promoter from cotton].

To study the expression of late embryogenesis abundant gene in seeds, the 1,024 bp 5' flanking sequence of D-113 gene, a late embryogenesis abundant gene of Gossypium hirsutum cv. Coker 312, was cloned by PCR. The similarity compared with the sequence of Lea protein gene family published was 92.50%. There are three putative ABREs and one enhancer-like which riches A/T in the promoter. The promoter was fused to the beta-glucuronidase gene to form pLD II. Via a particle bombardment, pLD II was introduced into embryogenic calli of cotton and seeds of Brassica napus which were all treated with abscisic acid for 3d before bombardment, also into roots, stems and leafs of cotton. Transient expression was measured histochemically as spot number 24 h after bombardment. GUS sexpression was observed in the seeds of Brassica napus and the embryogenic calli of cotton, but not found in roots and leaves of cotton. Those results indicated that the expression of D-113 gene promoter was embryo specific.

[Cloning of a MADS box protein gene (GhMADS1) from cotton (Gossypium hirsutum L.)].

As a kind of transcription factors, MADS-box protein plays an important role in various cellular processes, especially in the development of floral organs. Based on the contig analysis of the cotton ESTs, the coding region of a cotton MADS-box protein (GhMADS1) was obtained by RT-PCR from floral buds of cotton (G. hirsutum). The cloned fragment of 713 bp (GhMADS1, GenBank accession no. AF538965) contains an open reading frame of 711 bp,coding a polypeptide of 236 amino acids. It was demonstrated that the deduced GhMADS1 protein was highly homologous to the AGL2 group of MADS-box proteins from Vitis vinifera, Nicotiana sylvestris, Petunia hybrida, Arabidopsis thaliana and Antirrhinum majus. Phylogenetic analysis also indicated that GhMADS1 belongs to the AGL2 group of MADS-box proteins. RT-PCR analysis showed that GhMADS1 gene expressed in petals, stamens, ovules and fibers, but not in roots, stems, leaves, bracts and sepals. The strongest expression of GhMADS1 gene was detected in petals. But in floral buds of a cotton homeotic mutant (CHV1), whose floral organs are all converted to bract leaf-like organs, the transcript of GhMADS1 gene was not detected. It was proposed that GhMADS1 gene would be crucial to the development of cotton floral organs.

[Estimation and forecast of chlorophyll a concentration in Taihu Lake based on ensemble square root filters].

Chlorophyll a concentration is one of the important parameters for the characterization of water quality, which reflects the degree of eutrophication and algae content in the water body. It is also an important factor in determining water spectral reflectance. Chlorophyll a concentration is an important water quality parameter in water quality remote sensing. Remote sensing quantitative retrieval of chlorophyll a concentration can provide new ideas and methods for the monitoring and evaluation of lake water quality. In this work, we developed a data assimilation scheme based on ensemble square root filters and three-dimensional numerical modeling for wind-driven circulation and pollutant transport to assimilate the concentration of chlorophyll a. We also conducted some assimilation experiments using buoy observation data on May 20, 2010. We estimated the concentration of chlorophyll a in Taihu Lake, and then used this result to forecast the concentration of chlorophyll a. During the assimilation stage, the root mean square error reduced from 1.58, 1.025, and 2.76 to 0.465, 0.276, and 1.01, respectively, and the average relative error reduced from 0.2 to 0.05, 0.046, and 0.069, respectively. During the prediction stage, the root mean square error reduced from 1.486, 1.143, and 2.38 to 0.017, 0.147, and 0.23, respectively, and the average relative error reduced from 0.2 to 0.002, 0.025, and 0.019, respectively. The final results indicate that the method of data assimilation can significantly improve the accuracy in the estimation and prediction of chlorophyll a concentration in Taihu Lake.

[Research of hyperspectral reconstruction based on HJ1A-CCD data].

By restoring plentiful spectral information from several bands, hyperspectral image reconstruction could provide more suitable data source to water environment remote sensing. This is significant for inland water color remote sensing. By using the HJ1 A-HSI and HJ1A-CCD image acquired on June 6th, 2009, the hyperspectral data was reconstructed from HJ1A-CCD data. The results show that: (1) The average relative error of HJ1A-HSI data and reconstructed data compared with measured Rrs at 660 nm-900 nm are 0.333 5 and 0.307 7, respectively; (2) The entropy and average gradient of reconstructed image are higher than HJ1A-HSI image. In additional, the three band model get higher accuracy when inversing chl-a concentration by the reconstructed data.

[Construction of semi-analytical model for inversing total suspended matter in Lake Taihu and Chaohu and assessment of its applicability].

Total suspended matter is an important water quality parameter. Firstly, a semi-analytical model for inversing concentration of total suspended matter was constructed by simplifying the bio-optical model, using the in-situ data of Lake Taihu in spring and autumn and that of Lake Chaohu in summer. And then, its applicability was validated by MERIS and HJ-1 HSI data. The results showed that: (1) The optical range for inversing total suspended matter in Lake Taihu and Chaohu was between 730 nm and 832 nm except the oxygen absorption bands. (2) According to MERIS data, bands centered at 754 nm and 779 nm were both suitable for inversing total suspended matter in Lake Taihu whereas the band centered at 761 nm was not suitable due to the influence of oxygen absorption. (3) According to MERIS data, the relative error of this model increased with the time difference after satellite transit time. The relative errors of inversion results of this model were below 50% when the time difference was less than 3 hours, while they increased to more than 50% when the time difference exceeded 3 hours. (4) The seventeen bands of HJ-1 HSI data were all suitable for inversing total suspended matter in Lake Chaohu and its result was better than that in Lake Taihu using MERIS data.

[Estimation and remote sensing inversion of diffuse attenuation coefficient Kd(490) in Lake Taihu in spring based on semi-analytical model].

Diffuse attenuation coefficient is not only an important optical parameter, but also an important factor of water ecological system. Two datasets measured in April 2009 and May 2010 were firstly used to calculate absorption coefficient [a (490)] and backscattering coefficient [b(b) (490)] at 490 nm, and then, the relationship between b(b) (490) and simulated remote sensing reflectance at different bands of HJ-1 was studied. The semi-analytical model of Kd (490) in Lake Taihu in spring was constructed based on this basis, and it was used to estimate Kd (490) of Lake Taihu via an image of HJ-1 finally. The results show that: 1) The values of a(490) and b(b)(490) can be calculated accurately based on optical closure principle, and the mean absolute percent error (MAPE) of a(490) between calculated and measured is 17.1%. In addition, the backscattering coefficient at 490 nm [b(b) (490)] exponentially relate with the simulated remote sensing reflectance at the fourth band of HJ-1; 2) The semi-analytical model constructed in this study has good accuracy and stability. The MAPE is 21.6% and RMSE is 1.68 m(-1) by comparing inversion result and quasi-synchronous measured data; 3) Kd (490) of Lake Taihu in spring differs a lot in space distribution. The values are relatively smaller in north and east part of Lake Taihu, but larger in west and south part.

[Simulation of backscattering coefficients of inland waters].

When we simulated backscattering coefficients (b(bp)) using quasi-analytical algorithm and optical closure theory, it was found that the position of reference wavelength (lambda(0)) had great impact on final results. In order to identify influence factors of the optimum lambda(0), datasets of Lake Taihu, Lake Chaohu and Lake Dianchi were used. After simulating of b(bp), the relationship between optimum lambda(0) and associated water quality parameters were analyzed. Meanwhile, power functions were utilized to model b(bp) spectra, and spectral slope parameters of Lake Taihu, Lake Chaohu and Lake Dianchi were 2.643 +/- 0.317, 2.719 +/- 0.242, 1.638 +/- 0.534, respectively. The results indicate that: (1) When the whole lakes are taken as objects of study, the lambda(0) should be changed to longer wavelength with the increasing of total suspended particle matter concentration (c(SPM)), suspended organic particle matter concentration (c(SPOM)) and chlorophyll a concentration (c(CHL)), the optimum location of lambda(0) of Lake Taihu is 695 nm, Lake Chaohu is 720 nm and Lake Dianchi is 730 nm; (2) When the samples in lakes are taken as objects of study, the influence factors are different due to the complexity of optical properties of inland waters. But it is to be noted that, c(SPM) is a key factor in common. Besides, the regularity mentioned above should be weakened with high c(CHL). (3) The relationship between b(bp) and c(SPM) is much stronger in the waters with suspended particles dominated by inorganic particles, in Lake Taihu, for example, relationship between these two variables is strong with R2 = 0.852.

Analysis of floral morphology of a cotton homeotic variant (CHV1).

Physiological and genetic variations exist frequently in the cotton plants regenerated from somatic embryos. A stable homeotic variant (CHV1) was identified from these regenerated plants. Morphological analysis suggested that all the floral organs of the CHV1 plants convert into bract leaf-like organs, this was confirmed by close inspection of floral organs surface using scanning electron microscope. However, there are placenta and ovules bearing at the basal region of central leaf-like organs. A flower of the variant consists of three to seven bracts, nineteen to fourty one bract leaf-like organs. Arrangement of the leaf-like organs is intermediate between spiral and whorl. The mechanisms responsible for the CHV1 phenotype are analyzed. The variant (CHV1) may be useful in the research of cotton flower development and the mechanism of somaclonal variation.