The Radcliffe Wave Parameters from Data on Open Star Clusters

A spectral analysis of the vertical positions and velocities of 374 open star clusters(OSCs)was carried out.We took these OSCs from the Hunt and Reffert catalog;they have an average age of about 10 million years,and are located on the galactic plane XY in a narrow zone inclined by 25°to the galactic axis Y.The following estimates of the parameters of the Radcliffe wave were obtained:(a)the maximum value in periodic perturbations of vertical coordinates Z_(max)=92±10pc with the wavelength of these perturbations λ_(z)=4.82±0.09 kpc;(b)the maximum value of the velocity of vertical disturbances Wmax=4.36±0.12km s^(-1) with disturbance wavelengthλ_(W)=1.78±0.02 kpc.Note that the results of the vertical velocity analysis are first-class in accuracy and completely new.

Observation of HⅠaround three Satellite Galaxies of M31 with FAST:AndromedaⅡ,NGC 205,and NGC 185

With the exceptional sensitivity of the Five-hundred-meter Aperture Spherical radio Telescope,we conducted observations of the neutral hydrogen(HⅠ)in the circumgalactic medium of Andromeda’s(M31)satellite galaxies,specifically AndromedaⅡ,NGC 205,and NGC 185.Initially,three drift scans were executed for these satellites,with a detection limit of 4×10^(18)cm^(-2)(approximately 1.88×10^(3)M_Θof HⅠmass),followed by a more in-depth scan of a specific region.We discovered a C-shaped HⅠarc structure sharing a position and line-of-sight velocity similar to a stellar ring structure around AndromedaⅡ,hinting at a potential connection with AndromedaⅡ.In the context of NGC 205,we identified two mass concentrations in the northeast direction,which could be indicative of tidal streams resulting from the interaction between this galaxy and M31.These new lumps discovered could be very helpful in solving the missing interstellar medium problem for NGC 205.Observations regarding NGC 185are consistent with previous studies,and we did not detect any additional HⅠmaterial around this galaxy.These observational results enhance our understanding of the evolution of these satellite galaxies and provide insight into their historical interactions with the galaxy M31.

Local structure-preserving methods for the generalized Rosenau-RLW-KdV equation with power law nonlinearity

Local structure-preserving algorithms including multi-symplectic, local energy- and momentum-preserving schemes are proposed for the generalized Rosenau-RLW-KdV equation based on the multi-symplectic Hamiltonian formula of the equation. Each of the present algorithms holds a discrete conservation law in any time-space region. For the original problem subjected to appropriate boundary conditions, these algorithms will be globally conservative. Discrete fast Fourier transform makes a significant improvement to the computational efficiency of schemes. Numerical results show that the proposed algorithms have satisfactory performance in providing an accurate solution and preserving the discrete invariants.

The Environment and Star Formation around the Infrared Bubble N 13

Infrared bubbles provide a unique opportunity to study the interactions between massive stars and surrounding material.We conduct a multi-wavelength study on the environment and star formation around an infrared bubble N13.Three dust clumps and two molecular clumps are identified around N 13,which are all distributed on the layer.Young stellar objects(YSOs)are carefully searched using infrared colors and YSO candidates of WISE and Gaia DR2,and three Class I/II YSOs are found in N 13.In addition,four O-type stars identified in N 13 are probably the exciting stars.The dynamical and fragmentation ages of N 13 are 0.32-0.35 and 1.37-2.80 Myr respectively,which suggest that the radiation-driven implosion model may be dominant in N 13.By comparing the small-size bubble N 13(R~1.9 pc)and the larger-size bubble G15.684-0.29(R~15.7 pc)we found that star formation activity is more active in the large-size bubble.Brief comparisons of ten bubbles show that small-size bubbles have a small ratio of kinetic age versus the fragmentation time.Triggering star formation may be more active in bubbles with larger ratio between kinetic and fragmentation ages.Furthermore,the collect and collapse mechanism may play the dominant role in the large-size ones.

Virtual screening and optimization of typeⅡ inhibitors of JAK2 from a natural product library

OBJECTIVE To utilize a structure-based lead optimization approach to generate novel natural product-like typeⅡ inhibitors of JAK2 using the DOLPHIN protocol.METHODS Initially,the DOLHPIN computational protocol was employed to convert an active(DFG-in)conformation of JAK2 into a typeⅡ-compatible conformation,which was used as a model for the structure-based virtual screening of 150 000 natural product-like compounds in silico.The novel biflavonoid analogues were designed and synthesized based on the structure of lead compound and then tested for JAK2 and STAT3 inhibitory activity,cytotoxicity and HCV antiviral activity.RESULTS The top eleven highest-scoring compounds were generated from the initial high-throughput virtual screening.Amentoflavone 1a,a biflavonoid from the Chinese plant Gingko biloba,emerged as a promising candidate for further biological evaluation.In dose-response experiments,amentoflavone 1ainhibited JAK2 activity in a concentration dependent fashion with an IC50 value of 5μmol·L-1.As a proof-of-concept,we designed nine analogues 1b-1j with the addition of one or more aliphatic side chains to the biflavonoid scaffold of 1a.The octyl(C8)analogue 1bdisplayed superior potency against JAK2 activity and HCV activity compared to the parent compound 1a,validating the structure-based lead optimization approach used in this study.Moreover,kinetic analysis indicated that analogue 1bexhibited a non-competitive mode of inhibition,suggesting that this compound may be a putative typeⅡ inhibitor of JAK2.CONCLUSION Amentoflavone 1ahas been identified as a JAK2 inhibitor by structure-based virtual screening of a natural product library.In silico optimization using the DOLPHIN model yielded analogues with enhanced potency against JAK2 activity and HCV activity in cellulo.Molecular modeling and kinetic experiments suggested that the analogues may function as typeⅡ inhibitors of JAK2.

QSPR Studies on the Octanol/water Partition Coefficient (lgK_(ow)) of Substituted Anilines with 2D and 3D Methods

Octanol/water partition coefficient （Kow） is a crucial property for evaluating the environmental behavior and fate of organic compound. Herein, some quantitative structure-property relationship （QSPR） studies were performed to estimate and predict the lgK ow of substituted anilines. 2D method （multiple linear regression, MLR） and 3D method （comparative molecular field analysis, CoMFA） were applied in this study. Successful 2D and 3D models yielded the correlation coefficient （R2） values of 0.981 and 0.966 and the Leave-One-Out （LOO） cross-validated correlation coefficient （q2） values of 0.933 and 0.820, respectively. The developed models have a highly predictive ability in both internal and external validation. In addition, the results were interpreted in terms of physical and chemical meanings of descriptors and field contribution maps. It showed that the steric and electrostatic properties are the primary factors that govern the lgK ow of substituted anilines. The information obtained from the QSPR models would be helpful to the interpretation of structural features pertinent to the lgK ow of substituted anilines, which may be helpful in estimating the organic compounds＇ potential harm to the environment.

Calculation of Hildebrand Solubility Parameters of Some Polymers Using QSPR Methods Based on LS-SVM Technique and Theoretical Molecular Descriptors

In this work, some chemometrics methods are applied for the modeling and prediction of the Hildebrand solubility parameter of some polymers. A genetic algorithm （GA） method is designed for the selection of variables to construct two models using the multiple linear regression （MLR） and least square-support vector machine （LS-SVM） methods in order to predict the Hildebrand solubility parameter. The MLR method is used to build a linear relationship between the molecular descriptors and the Hildebrand solubility parameter for these compounds. Then the LS-SVM method is utilized to construct the non-linear quantitative structure-activity relationship （QSAR） models. The results obtained using the LS-SVM method are then compared with those obtained for the MLR method; it was revealed that the LS-SVM model was much better than the MLR one. The root-mean-square errors of the training set and the test set for the LS-SVM model were 0.2912 and 0.2427, and the correlation coefficients were 0.9662 and 0.9518, respectively. This paper provides a new and effective method for predicting the Hildebrand solubility parameter for some polymers, and also reveals that the LS-SVM method can be used as a powerful chemometrics tool for the quantitative structure-property relationship （QSPR） studies.