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At present, the core of lidar data registration algorithms depends on search correspondence, which has become the core factor limiting the performance of this kind of algorithm. For point-based algorithms, the data coincidence rate is too low, and for line-based algorithms, the method of searching the correspondence is too complex and unstable. In this paper, a laser radar data registration algorithm based on DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering is proposed, which avoids the search and establishment of the corresponding relationship. Firstly, a ring band filter is designed to process the outliers with noise in a point cloud. Then, the adaptive threshold is used to extract the line segment features in the laser radar point cloud. For the point cloud to be registered, a DBSCAN density clustering algorithm is used to obtain the key clusters of the rotation angle and translation matrix. In order to evaluate the similarity of the two frames of the point cloud in the key clusters after data registration, a kernel density estimation method is proposed to describe the registered point cloud, and K-L divergence is used to find the optimal value in the key clusters. The experimental results show that the proposed algorithm avoids the direct search of the correspondence between points or lines in complex scenes with many outliers in laser point clouds, which can effectively improve the robustness of the algorithm and suppress the influence of outliers on the algorithm. The relative error between the registration result and the actual value is within 10%, and the accuracy is better than the ICP algorithm.

TianQin is a proposed geocentric space-based gravitational wave observatory mission, which requires time-delay interferometry (TDI) to cancel laser frequency noise. With high demands for precision, solar-wind plasma environment at $\sim 10^5$ km above the Earth may constitute a non-negligible noise source to laser interferometric measurements between satellites, as charged particles perturb the refractivity along light paths. In this paper, we first assess the plasma noises along single links from space-weather models and numerical orbits, and analyze the time and frequency domain characteristics. Particularly, to capture the plasma noise in the entire measurement band of $10^{-4} - 1$ Hz, we have performed additional space-weather magnetohydrodynamic simulations in finer spatial and temporal resolutions and utilized Kolmogorov spectra in high-frequency data generation. Then we evaluate the residual plasma noises of the first- and second-generation TDI combinations. Both analytical and numerical estimations have shown that under normal solar conditions the plasma noise after TDI is less than the secondary noise requirement. Moreover, TDI is shown to exhibit moderate suppression on the plasma noise below $\sim 10^{-2}$ Hz due to noise correlation between different arms, when compared with the secondary noise before and after TDI., 12 pages, 15 figures, accepted by Phys. Rev. D

Zero-order terahertz Bessel beams are diffractom-free. Therefore, unlike the traditional Gaussian beam CT, the terahertz zero-order Bessel beam used in terahertz CT imaging can improve the depth of field of the imaging system. At the same time, the imaging system has high lateral resolution. Bessel beam CT was used to scan a variety of samples at the same time and the reconstruction results were obtained. The reconstructed sections and three-dimensional structures of the scanned samples were clearly seen.

IntroductionAccumulating evidence has shown the potential of bergamottin as an anticancer agent. The present study was undertaken to evaluate the anticancer affects of bergamottin (µM) against colon cancer cells.Material and methodsAntiproliferative effects were evaluated by WST-1 cell viability assay. Apoptotic effects were studied by DAPI and Annexin V/PI staining. Cell cycle analysis was carried out by flow cytometry. Transwell assay was used to study the effects on cell invasion. Protein expression was estimated by the western blot method.ResultsThe results showed that bergamottin suppresses the proliferation of all the human colon cancer cell lines. Nonetheless, the growth inhibitory effects of bergamottin on the HT-29 and RKO cells were more significant (IC50, 12.5 µM). The anticancer effects of bergamottin on the HT-29 and RKO cells were mainly due to apoptosis. Bergamottin could considerably increase the expression of Bax and reduce the expression Bcl-2. The cleavage of caspase-3, 8 and 9 was also enhanced upon bergamottin treatment of the colon cancer cells. Flow cytometric analysis showed that bergamottin also induced G2/M cell cycle arrest of the HT-29 and RKO cells. Additionally, bergamottin could also suppress the invasion of HT-29 and RKO cells. The Raf/MEK/ERK pathway is regarded as one of the essential pathways involved in the development and progression of cancers. Herein, it was observed that bergamottin could concentration dependently block this pathway in colon cancer cells. In vivo study revealed that bergamottin could also suppress the growth of tumours in xenografted mice models.ConclusionsTaken together, bergamottin suppresses the proliferation of colon cancer cells and may be utilised in the development of chemotherapy for colon cancer.

Four Ln(III) complexes based on a new nitronyl nitroxide radical have been synthesized and structurally characterized: {Ln(hfac)3[NITPh(OMe)2]2} (Ln = Eu(1), Gd(2), Tb(3), Dy(4); NITPh(OMe)2 = 2-(3΄,4΄-dimethoxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; hfac = hexafluoroacetylacetonate;). The single-crystal X-ray diffraction analysis shows that these complexes have similar mononuclear tri-spin structures, in which central Ln(III) ion is eight-coordinated by two oxygen atoms from two nitroxide groups and six oxygen atoms from three hfac anions. The variable-temperature magnetic susceptibility study reveals that there exist ferromagnetic interactions between Gd(III) and the radicals, and antiferromagnetic interactions between two radicals (JGd-Rad = 3.40 cm−1, JRad-Rad = -9.99 cm−1) in complex 2. Meanwhile antiferromagnetic interactions are estimated between Eu(III) (or Dy(III)) and radicals in complexes 1 and 4, and ferromagnetic interaction between Tb(III) and radicals in complex 3, respectively. This article is protected by copyright. All rights reserved.

Four new nitronyl nitroxide radical-Ln(III) complexes, Ln(hfac)3(NITPhSCF3)2 (Ln(III) = Sm(1), Gd(2), Tb(3), Dy(4); NITPhSCF3 = 2-(4-trifluoromethylthiophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl- 3-oxide; hfac = hexafluoroacetylacetonate), have been synthesized and characterized. They are isostructural, which show mononuclear tri-spin structures. The central Ln(III) ion is eight-coordinated by three hfac anions and two NITPhSCF3 molecules. Direct-current magnetic study shows that there exist ferromagnetic interactions between Gd(III) ion and radicals (NITPhSCF3) with JGd-Rad = 1.61 cm−1, and antiferromagnetic interactions between radicals with JRad-Rad = −2.83 cm−1 in complex 2. The magnetic analysis with the rough approximate model show that a ferromagnetic coupling exists between Tb(III) and radical in 3, while a antiferromagnetic coupling between Dy(III) and radical in 4. The thermodynamics properties of four complexes were studied with differential scanning calorimetry (DSC), such as heat capacity, thermodynamic functions (HT-H298.15K), (ST-S298.15K), and (GT-G298.15K).

Five rare earth heterospin complexes [Ln(hfac)3(NITptBuPh)2], [LnIII = Eu (1), Tb (2), Dy (3), Ho (4), Er (5)] (hfac = hexafluoroacetylacetonate), were synthesized with the radical ligand NITptBuPh [2-(4′-tert-butylphenyl)-4, 4,5, 5-tetramethylimidazoline-1-oxyl-3-oxide]. These complexes exhibit similar structures. All of them crystallize in the monoclinic space group P21/c, and consist of discrete mononuclear molecules. The central LnIII ion is eight-coordinate with a distorted dodecahedral environment. The NITptBuPh radical acts as monodentate ligand towards LnIII ion through the NO group. The magnetic studies suggested weak antiferromagnetic interactions between LnIII ion and radicals in 1, 3, 4, and 5, but weak ferromagnetic interaction in 2.

The title compound {[Co2(NIT4Py)4(fum)2(H2O)4] · (H2O)2} n , where NIT4Py = 2-(4′-pyridinyl)-4,4,5,5-tetra-methylimidazoline-1-oxyl-3-oxide and fum = fumarate, was prepared and structurally characterized by X-ray diffraction. It crystallizes in triclinic, space group P 1 with a = 9.8853(9) A, b = 13.2167(13) A, c = 13.8481(12) A, α = 68.5400(10)°, β = 73.467(2)°, γ = 74.596(2)°, V = 1587.6(3) A3, Z = 1, and R 1 [I > 2σ(I)] = 0.0662. The complex consists of two kinds of neutral infinite 1-D chains, in which [Co(NIT4Py)2(H2O)2] moieties are connected by fumarate anions in a bis-monodentate mode. These 1-D chains are further connected by hydrogen bonds, generating a 2-D network. The variable temperature magnetic susceptibility measurement reveals that the magnetic couplings between Co(II) and NIT4Py are weak antiferromagnetic interactions.

Two new complexes [Mn(NIT4Py)(2,4-PDA)(H 2 O) 2 ] ( 1 ) and [Co(NIT4Py)(2,4-PDA)(H 2 O) 2 ] ( 2 ) (where NIT4Py stands for 2-(4′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, 2,4-PDA stands for pyridine-2,4-dicarboxylate) have been synthesized and characterized. The single-crystal X-ray diffraction demonstrates that complex 1 present dimeric structure with two 2,4-PDA anions function as bridging ligands, connecting two Mn(II) centers. The dimeric units form an infinite 2D double-layered network via hydrogen bonds. Complex 2 consists of infinite 1D chain, in which each 2,4-PDA anion bridges two adjacent Co(II) ions in monodentate–bidentate mode. These 1D chains are further connected together by hydrogen bonds, generating a 2D double-layered structure, too. The variable temperature magnetic susceptibility measurements reveal that the magnetic couplings between Mn(II) and NIT4Py, Co(II) and NIT4Py are weak ferromagnetic and antiferromagnetic interactions for complexes 1 and 2 , respectively.

A series of undecatungstozincate complexes, K n H[ZnW 11 O 39 M(H 2 O)]·X·H 2 O (M = Ni, Cu, Mn, Co, Fe or Ti), has been prepared and characterized by elemental analysis, 183 W NMR and electrochemistry. The title heteropolyanions catalyse olefin epoxidation by iodosylbenzene or 30% aqueous H 2 O 2 .

A new analytical method for the determination of uric acid (UA) by the perturbation of UA on the Belousov-Zhabotinsky oscillating reaction is proposed. The method is based on the linear relationship between the changes in the oscillating period and the concentration of UA. The calibration curve is linear over the range of 2.0 x 10(-5) to 5.0 x 10(-4)M, with a detecting limit of 3.28 x 10(-6)M. The method features good precision (R.S.D.: 3.59%) and excellent throughput (10samplesh(-1)). The possible mechanism of the perturbation of UA on the oscillating reaction is discussed.