Hexahedron Structure Research Articles

Drug loading strategy of modular self‐assembly mode: Curcumin pyrimidine derivatives mediated by pH‐sensitive materials

AbstractChemotherapy drugs often cause various adverse reactions and affect normal tissues, so it is of great significance to design effective targeted anti‐tumor drug delivery methods. We constructed a series of self‐assembled supramolecular modular structures and explored whether they could become an effective targeted antitumor fluorescent agent. UV and fluorescence spectra show that it has fluorescence. The drug release curve was determined by dialysis method and the results showed that the release rate of PCB series composites was the highest under pH = 5. The curcumin pyrimidine derivative was embedded in the structure, and the formation of the complex was confirmed by infrared spectroscopy. The results for the cell imaging indicated that with the decrease of environmental pH value, the ability of PCB‐1 and PCB‐2 to penetrate the biofilm barrier into cells increased, suggesting that they have targeting action. The results of the cell viability test showed that PCB‐1 and PCB‐2 had a good inhibitory effect on MGC and HeLa cells. TEM showed that PCB‐1 was a regular hexahedron structure and PCB‐2 was a rod structure. In addition, the encapsulation efficiency of PCB‐1 and PCB‐2 was tested to be 86.50% and 88.57%, respectively, with drug loading rates of 27.62% and 28.38%, and Zeta potential values of +35 and +32. In conclusion, PCB‐1 and PCB‐2 are good potential anti‐tumor fluorescent agents.

Computation of resistance distance and Kirchhoff index of chain of triangular bipyramid hexahedron

The two point effective resistance in some electrical networks has been extensively studied by many mathematicians and physicists. The computation of the effective resistance among two points in a network is a well-known problem in electrical networks theory. To solve this problem, we can apply methods such as the series principle, parallel principle, star-mesh transformation and Delta-Y transformation. The resistance distance among vertices u and v in a graph G is the effective resistance among the corresponding points in the given electrical network obtained from G by converting each edge of G with resistor of 1 ohm. The Kirchhoff index is the sum of resistance distance between all pairs of vertices of graph G. Chain of triangular bipyramid hexahedron structure which is a polyhedral graph has many applications in the area of reticular chemistry. In our paper, we compute the resistance distance among all pairs of vertices in the chain of triangular bipyramid hexahedron. Also we compute the closed formula for Kirchhoff index.

Relationship between topological structures and mechanical properties of artificially architected SiC cellular ceramics: Experimental and numerical study

Due to their topological superiority, the architected materials facilitate the improvement of the physical and mechanical properties of cellular materials. With the progress of additive manufacturing technologies, the fabrication of architected silicon carbide (SiC) cellular ceramics has become achievable. This study focuses on the indirect additive manufacturing method of SiC cellular ceramics consisting of 3D printing, replication, and reaction-bonded sintering. To study the impact of the topology on the mechanical performance, three strut-based unit cell structures and stochastic foam with robust solid struts were experimentally and numerically studied. Results showed that the hexahedron structure has the highest compression strength, the tetrakaidecahedron structure has the highest flexural strength, while the regular structures have higher mechanical performance than the stochastic foam. The deformation mechanisms of the topologies under the compression load indicated that the hexahedron, tetrakaidecahedron, and stochastic foam favor the bending-dominated deformation mode, while the octet favors the stretching-dominated deformation mode.

Image encryption algorithm based on a new chaotic system with Rubik's cube transform and Brownian motion model

In this paper a new two-dimensional chaotic map based on Logistic map and Chebyshev map is proposed. The performance analysis and evaluation show the proposed map has a very wide range of chaos and good ergodicity. Further, a new image encryption algorithm is designed using the chaotic map with Rubik's Cube transform and Brownian motion model. The encryption process is ‘confusion - Rubik's cube transformation - diffusion’. In the confusion stage, a method combining Brownian motion theory and chaotic sequence is proposed. Then combining the advantages of chaotic system and Rubik's cube, a Rubik's Cube transformation algorithm is proposed. The scrambled pixel matrix and the chaotic matrix are spliced into a hexahedron structure, and the Rubik's Cube is dynamically scrambled through a pseudo-random sequence. Finally, the XOR operation is performed on the basis of the two-dimensional Hénon chaotic map. The experimental results show that the algorithm has the advantages of large key space, strong robustness and high security, and can resist common cryptanalysis attacks.

Design and analysis of three-dimensional printing of a porous titanium scaffold

ObjectiveMechanic strength, pore morphology and size are key factors for the three-dimensional (3D) printing of porous titanium scaffolds, therefore, developing optimal structure for the 3D printed titanium scaffold to fill bone defects in knee joints is instructive and important.MethodsStructural models of titanium scaffolds with fifteen different pore unit were designed with 3D printing computer software; five different scaffold shapes were designed: imitation diamond-60°, imitation diamond-90°, imitation diamond-120°, regular tetrahedron and regular hexahedron. Each structural shape was evaluated with three pore sizes (400, 600 and 800 μm), and fifteen types of cylindrical models (size: 20 mm; height: 20 mm). Autodesk Inventor software was used to determine the strength and safety of the models by simulating simple strength acting on the knee joints. We analyzed the data and found suitable models for the design of 3D printing of porous titanium scaffolds.ResultsFifteen different types of pore unit structural models were evaluated under positive pressure and lateral pressure; the compressive strength reduced when the pore size increased. Under torsional pressure, the strengths of the imitation diamond structure were similar when the pore size increased, and the strengths of the regular tetrahedron and regular hexahedron structures reduced when the pore size increased. In each case, the compressive strength of the regular hexahedron structure was highest, that of the regular tetrahedron was second highest, and that of the imitation diamond structure was relatively low. Fifteen types of cylindrical models under a set force were evaluated, and the sequence of comprehensive compressive strength, from strong to weak was: regular hexahedron > regular tetrahedron > imitation diamond-120° > imitation diamond-90° > imitation diamond-60°. The compressive strength of cylinder models was higher when the pore size was smaller.ConclusionThe pore size and pore morphology were important factors influencing the compressive strength. The strength of each structure reduced when the pore size (400, 600 and 800 μm) increased. The models of regular hexahedron, regular tetrahedron and imitation diamond-120°appeared to meet the conditions of large pore sizes and high compressive strength.

In-situ amino-functionalization of zeolitic imidazolate frameworks for high-efficiency capture of low-concentration CO2 from flue gas

The capture of low-concentration CO2 from flue gas is an on-going challenge. In this work, a novel series of amino-functionalized zeolitic imidazolate framework-8 materials (ZIF-DIA) was facilely synthesized via in-situ incorporating an large-size amino-functional imidazolium ligand during the synthesis process under atmospheric conditions, and its adsorption performance of CO2 from a simulated flue gas (15 vol% CO2) was investigated. With the introduction of amino-functional imidazolium ligand, the regular hexahedron structure of pure ZIF-8 is gradually converted into cluster-like morphology. The amino-functionalized ZIF materials exhibit high specific surface areas (712–941 m2·g−1), rapid CO2 adsorption rate (≤80 s), excellent CO2 adsorption capacities of up to 6.17 mmol·g−1 under wide temperature range (35–110 °C), overwhelming that of pure ZIF-8 (≤1.96 mmol·g−1) and other reported metal–organic frameworks (MOFs). DFT calculation verified that π-π stacking and hydrogen bonding between imidazole/aromatic rings on ligands and CO2 play crucial role in high CO2 uptake. Excellent recyclability in 10 runs under both low and high temperatures (55 °C, 110 °C) is exhibited, endowing this kind of materials with great potential for practical applications.

Histological characteristics of bone in-growth of proximal humeral implants with different spatial structures.

This study compares the longitudinal histological characteristics of proximal humeral implants with different spatial structures in rabbits. Thirty skeletally-mature male rabbits were divided into a trabecular structure group and regular hexahedron structure group according to the different spatial structures of a biological titanium alloy screw inserted into the greater tuberosity of the proximal humerus. Samples were collected 3, 6, and 12 weeks after the implantation surgery. Histological results showed that the amount of bone in-growth in the porous cavity of the screw implant increased over time. Quantitative analysis showed there was significantly more bone in-growth in the trabecular structure group than the classic structure group 3 weeks (25.4% ± 6.9% vs 19.6% ± 3.7%, P < 0.05) and 6 weeks (31.2% ± 1.7% vs 26.9% ± 5.3, P < 0.05) after the implantation surgery. No significant difference was detected between the two groups 12 weeks after the surgery (41.7% ± 2.5% vs 39% ± 4.1%, P > 0.05). Our data found that bone in-growth significantly differed among the three time points (P < 0.05) in both groups, but not between the implants with different spatial structures 12 weeks after the surgery.

Method of Real-Time Wellbore Surface Reconstruction Based on Spiral Contour

A wellbore surface is an irregular surface structure. The distribution of points on the wellbore surface measured based on the drilling diameter is not uniform. Thus, the conventional modeling method based on a point cloud cannot satisfy the needs of real-time measurement updating and wellbore display. This study proposes a spiral profile method for drilling shaft surface reconstruction. Scattered data along the drilling diameter are measured, and an inverse distance weighting cylindrical space surface algorithm with iterative interpolation is used to obtain the spiral angle and pitch of a relatively homogeneous helical contour line along the surface of the shaft. Using sets of four adjacent points in the spiral, quadrilaterals are formed, and then all obtained quadrilaterals are used to form the wellbore inner surface structure. This method can further construct the outer surface spiral contour line to advance the quadrilateral surface to the spatial hexahedron structure. The caliper and gamma measurement data obtained from the calibrated wellbore were used to verify the real-time surface reconstruction and fusion while drilling. The homogenized reconstructed surface profile is more than 99.5% similar to the actual measurement. Proved by experiment and application, this method has very high real-time performance, and the three-dimensional stereo imaging wellbore with additional gamma attributes has good visual effects.

Characterization, antioxidant, and anticancer activities of a neutral polysaccharide from Duchesnea indica (Andr.) Focke.

A neutral polysaccharide (DIP-1) from Duchesnea indica (Andr.) Focke was obtained by hot water extraction, ethanol precipitation and chromatographic separation (DEAE-52 cellulose anion-exchange column and Sephadex G-100 gel column). The physicochemical properties of DIP-1 were elucidated by gel permeation chromatography, monosaccharide composition, Fourier transform infrared spectrometry, UV-visible spectrophotometry, scanning electron microscope and Congo red test. The results indicated that DIP-1 was consisted of mannose, glucosamine, glucose, galactose and arabinose in a ratio of 1.00:0.42:18.36:14.17:0.81, and its molecular weight was 218.3kDa. Meanwhile, DIP-1 presented a straight hexahedron structure, but no triple-helical conformation. In antioxidant activity tests, DIP-1 exhibited powerful scavenging activities on hydroxyl, DPPH, ABTS radicals and reducing power in a dose-dependent manner. Especially, DIP-1 demonstrated high inhibitory activities against SKOV-3 and Hep-G2 cells in vitro, with IC50 values of 1.42 and 1.23mg/ml, respectively. PRACTICAL APPLICATIONS: D. indica has been used for a long time as a Chinese medicine for therapy of many diseases, including cancer, inflammation, leprosy, fever, bleeding and so on. At present, polysaccharides have attracted comprehensive attention because of a large range of pharmacological and biological properties, including antitumor, antidiabetic, antioxidant and immunomodulatory activity. In the present study, we purified and characterized a neutral polysaccharide from D. indica for the first time. Moreover, the neutral polysaccharide exhibits significant antioxidant and antitumor activities. Therefore, the present study laid a foundation for the high-value application of D. indica polysaccharides in functional food and pharmaceutical industries.

Impact of Plasmonic Parameters on 7-nm Patterning in Plasmonic Computational Lithography.

For the wavelength reduction to overcome the diffraction limit of the optical lithography, the surface plasmon lithography (SPL) has lower cost and simpler system configuration than the extreme ultraviolet (EUV) lithography. In this paper, for the below 10-nm critical dimension (CD) as one of critical challenges in the lithography technology, SPL based on the SP interference and metamaterial in bowtie and hexahedron structures is proposed and demonstrated by using computer simulations such as the rigorous coupled-wave analysis (RCWA) method and the finite difference time domain (FDTD) method. For 193-nm wavelength, the minimum FWHM (the full width at half maximum) of the transverse magnetic (TM) intensity in xz plane (and yz plane) is 10-nm (and 7-nm) in a bowtie plasmonic structure. For hexahedron structures, the minimum 30-nm FWHM of TM intensity with 193-nm wavelength is improved to the minimum 16-nm FWHM by using metamaterial and SP interference.

Simulation Analysis and Performance Study of CoCrMo Porous Structure Manufactured by Selective Laser Melting

To fabricate porous implants with improved biocompatibility and mechanical properties that are matched to their application using selective laser melting (SLM), flow within the mold and compressive properties and performance of the porous structures must be comprehensively studied. Parametric modeling was used to build 3D models of octahedron and hexahedron structures. Finite element analysis was used to evaluate the mold flow and compressive properties of the parametric porous structures. A DiMetal-100 SLM molding apparatus was used to manufacture the porous structures and the results evaluated by light microscopy. The results showed that parametric modeling can produce robust models. Square structures caused higher blood cell adhesion than cylindrical structures. “Vortex” flow in square structures resulted in chaotic distribution of blood elements, whereas they were mostly distributed around the connecting parts in the cylindrical structures. No significant difference in elastic moduli or compressive strength was observed in square and cylindrical porous structures of identical characteristics. Hexahedron, square and cylindrical porous structures had the same stress–strain properties. For octahedron porous structures, cylindrical structures had higher stress–strain properties. Using these modeling and molding results, an important basis for designing and the direct manufacture of fixed biological implants is provided.

NiCo2O4 particles with diamond-shaped hexahedron structure for high-performance supercapacitors

Nickel cobalt oxide (NiCo2O4) particles with a diamond-shaped hexahedral porous sheet structure are successfully synthesized by a facile hydrothermal method, followed by calcination in one step. NiCo2O4-I and NiCo2O4-II particles are prepared using the same method with different contents of urea (CO(NH2)2) and ammonium fluoride (NH4F). The different morphologies of the NiCo2O4-I and NiCo2O4-II particles illustrate that CO(NH2)2 and NH4F play an important role in crystal growth. To verify the influence of NH4F and CO(NH2)2 on the morphology of the NiCo2O4 particles, the theory of crystal growth morphology is analyzed. The electrochemical measurements show that NiCo2O4 particles exhibit a high specific capacitance. At a current density of 1.0mAcm−2, the mass specific capacitances of the NiCo2O4-I and NiCo2O4-II electrodes are 690.75 and 1710.9Fg−1, respectively, in a 6M KOH aqueous electrolyte. The specific capacitances of the NiCo2O4-I and NiCo2O4-II electrodes remain ∼95.95% and ∼70.58% of the initial capacitance values after 5000 cycles, respectively. According to the two-electrode test, the NiCo2O4-II//AC asymmetric electrodes exhibited an ultrahigh energy density of 64.67Whkg−1 at the power density of 12kWkg-1, demonstrating its excellent application potential as an electrode material for supercapacitors.

Magnetic Field Model for Permanent Magnet Spherical Motor With Double Polyhedron Structure

This paper presents an analytical method for calculating the magnetic field for a permanent magnet spherical motor (PMSM) with double polyhedron structure. For the PMSM, stator coils and cylindrical permanent magnet (PM) poles locate at the fixed point of octahedron and hexahedron, respectively, and provide the uniform magnetic field. To analyze the magnetic field in the spherical coordinate, the cylindrical PM pole is approximated as a dihedral cone pole using geometrical equivalence principle. Moreover, considering the characteristics of hexahedron structure, a virtual equatorial layer is emphasized, and the corresponding periodic boundary condition can be built for solving the Laplace equation related to the virtual equator. Then, the Tait–Bryan rotation transformation is applied three times; thereby the overall magnetic field of the PM poles is obtained by the superposition principle. Both simulations and experiments are conducted to demonstrate the effectiveness of the proposed method. The results indicate that the analytical modeling can represent the magnetic field of the PMSM with a high precision.

Multifunctional CuS nanocrystals for inhibiting both osteosarcoma proliferation and bacterial infection by photothermal therapy

Photothermal therapy (PTT) has attracted great attention in cancer therapy because of high efficiency and low side effect. The semiconductors have been proved to be ideal photothermal agents in the past years. Herein, we synthesized a novel hexahedron structure of polyvinyl pyrrolidone (PVP) coating CuS nanocrystals (NCs) by a facile hydrothermal method. The synthesized CuS NCs (150 nm for average length of edge and 125 nm for length of width) have good biocompatibility due to their PVP coating and strong absorption in the near infrared region. Moreover, the CuS NCs exhibit high photothermal conversion efficiency as well as good antibacterial effect. Notably, the proliferation of osteosarcoma cancer cells can be efficiently inhibited both in vitro and in vivo by the fatal heat with very low concentration of CuS NCs under the near infrared ray at a power density of 0.5 W/cm2. Therefore, the CuS-PVP NCs have great potential to work as an ideal photothermal and antibacterial agent in clinical applications.

Fabrication and Mechanical Properties of Porous CP-TiUsing Selective Laser Melting (SLM)

Recently, porous structure has become focus for the study of implantable devices due to the superior ability of osseointegration. Meanwhile, Selective laser melting (SLM), a versatile rapid manufacturing method, is widely utilized in medical restoration field due to its flexibility. Given the information about mechanical properties and manufacturing process of porous structure is limited, the aim of this study is to investigate the manufacturing process and static mechanical properties. Therefore, regular hexahedron structures are designed and fabricated by SLM, also the dimensions and mechanical properties are evaluated by experiments. The results show that manufacturing process and design of structure have significant influence on porosity and mechanical properties. Porous structure would reduce the elastic modulus and yield strength, and the ductility of porous structure is poor than that of solid structure. Moreover, the suitable pore size is >0.7mm. In conclusion, porous implant has great potential to use in bone repair and further study should be done to obtain more information.

Optical and bonding characters of Hg type clusters

The configuration, bonding, molecule orbitals and the wavelength of absorption spectra of HgX (X = O, Te, Se, and S) molecules and their doping clusters have been systematically investigated at B3LYP level with LanL2DZ basis set. The calculated results showed that Hg2O2 had different bonding, orbitals and spectra than other HgO clusters due to the presence of an O–O bond. From analysis of the calculated wavelengths of absorption spectra, we have found that Hg4O4 (a; hexahedron structure) and Hg4O4 (b; planar octagon) had completely different absorption wavelengths. As for doping, vacancy doping changed the HOMO and the LUMO, and the spectra of clusters. In contrast, substitution doping did not influence the orbital compositions of the structures. Obviously, vacancy doping was more difficult than substitution doping. Finally, through comparison of orbitals, spectra and bonding of HgO, HgS, HgSe and HgTe molecules, we have discovered that the other clusters had completely different orbital compositions, spectra, and bonding from of HgO clusters.

Single crystalline zinc stannate nanoparticles for efficient photo-electrochemical devices

Single crystalline zinc stannate (Zn(2)SnO(4) and ZnSnO(3)) nanoparticles were synthesized by a simple one-step hydrothermal reaction with a high production yield. Zn(2)SnO(4) is a (111) face-exposed octahedron, whereas ZnSnO(3) is a (100) face-exposed hexahedron structure. In particular, Zn(2)SnO(4) exhibits an efficient performance for applications in dye-sensitized solar cells.

Ｈｅｘａｈｅｄｒｏｎ Ｒｕｂｂｅｒ Ａｃｔｕａｔｏｒ（ＨＲＡ）の開発

To realize an actuator with flexibility, it is effective to use pneumatic actuators because of pneumatic compressibility. In this paper, a new type of pneumatic rubber actuator is developed. The actuator is called a hexahedron rubber actuator (HRA) . HRA has a hexahedron structure constructed by four plates and two fiber nets, which cover a rubber bladder. Since a HRA produces a rotational motion, it is suitable for making a rotational joint without adding mechanical parts . In this paper, we reveal the static characteristics of the HRA. Furthermore it is experimentally demonstrated that the HRA can realize a good position control performance without oscillation by using hierarchical feedback control. Moreover, we propose an adaptive gain method for the position control of the HRA to simplify the gain tuning. The effectiveness of the proposed method is confirmed through some experimental results.

Microscopy Studies for the Deep-Anisotropic Etching of (100) Si Wafers

Several etching phenomena appeared during the Si membrane process were observed and analyzed. In case of deep etching to above 300 µm depth, the etch-defects existed at the etched surface could be classified into three categories such as hillocks, adhered reaction products and white residues. It was known that the hillocks had a pyramidal shape or trapizoidal hexahedron structures depending on the density and size of the reaction products. Also, the existence of etch-defects and the etch rate distribution over a whole 4-inch wafers were investigated when the surfaces to be etched were downward, upward horizontally and erective for the stirring bar in the solution. As the results, the downward and erected postures were favorable in the etch rate uniformity and the etch-defect removal, respectively.