Spacecraft formation flying in the port-Hamiltonian framework

The problem of controlling the relative position and velocity in multi-spacecraft formation flying in the planetary orbits is an enabling technology for current and future research. This paper proposes a family of tracking controllers for different dynamics of Spacecraft Formation Flying (SFF) in the framework of port-Hamiltonian (pH) systems through application of timed Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC). The leader–multi-follower architecture is used to address this problem. In this regard, first we model the spacecraft motion in the pH framework in the Earth Centered Inertial frame and then transform it to the Hill frame which is a special local coordinate system. By this technique, we may present a unified structure which encompasses linear/nonlinear dynamics, with/without perturbation. Then, using the timed IDA-PBC method and the contraction analysis, a new method for controlling a family of SFF dynamics is developed. The numerical simulations show the efficiency of the approach in two different cases of missions.

     

Green synthesis of isatin-based compounds

Research on Chemical Intermediates - Isatin and related derivatives are synthetically versatile substrates. These compounds can form a wide range of heterocyclic structures. These characteristics...     

Analysis,design and simulation of MIM plasmonic filters with different geometries for technical parameters improvement

In this paper, four optical filter topologies based on metal–insulator–metal waveguides are proposed and the designed structures are investigated numerically using finite-difference timedomain method. Triangular-shaped adjunctions have been added to the filter structures to improve their transmission spectrum. These improved structures consist of air as the insulator and silver as the metal. The relative permittivity of metal has been described via the Drude,Drude–Lorentz, and Palik models. The first filter's transmission spectrum shows an acceptable transmittance. In the second optimized filter, the transmission spectrum has been improved. The transmittance spectrum can be tuned through adjusting the edge of the triangle in these four optimized filters. As a result, the bandwidths of resonance spectra can be adjusted. The theory of such tapered structures will be investigated by the tapered transmission line and will be solved with the transfer matrix method. This method shows a better performance and higher transmission efficiency in comparison with the basic structures. On the other hand, the final filter has been chosen as the best one because of its hexagonal resonator. The main reason for having a better result is due to a longer interaction length in comparison with the circular resonator. This in turn creates much better energy coupling and results in higher transmission.     

Adaptive fuzzy voltage-based backstepping tracking control for uncertain robotic manipulators subject to partial state constraints and input delay

Nonlinear Dynamics - The aim of this paper is to tackle the problem of adaptive fuzzy voltage-based tracking control for uncertain electrically driven robotic manipulators subject to input delay...     

Synthesis and pharmacological properties of polysubstituted 2-amino-4H-pyran-3-carbonitrile derivatives

Molecular Diversity - 2-Amino-3-cyano-4H-chromenes are structural core motifs that received increasing attention in the last years due to their interesting potential pharmacological properties. In...     

Synthesis of Polymers Containing Potassium Acyltrifluoroborates (KATs) and Post-polymerization Ligation and Conjugation

We report the synthesis of monomers for atom-transfer radical polymerization (ATRP) and a reversible addition-fragmentation chain transfer (RAFT) agent bearing trifluoroborate iminiums (TIMs), which are quantitatively converted into potassium acyltrifluoroborates (KATs) after polymerization. The resulting KAT-containing polymers are suitable for rapid amide-forming ligations for both post-polymerization modification and polymer conjugation. The polymer conjugation occurs rapidly, even under dilute (micromolar) aqueous conditions at ambient temperatures, thereby enabling the synthesis of a variety of linear and star-shaped block copolymers. In addition, we applied post-polymerization modification to the covalent linking of a photocaged cyclic antibiotic (gramicidin S) to the side chains of the KAT-containing copolymer. Cellular assays revealed that the polymer–antibiotic conjugate is biocompatible and provides efficient light-controlled release of the antibiotic on demand.     

Assessment of antioxidant,cytotoxicity, antibacterial,antifungal, and cutaneous wound healing activities of green synthesized manganese nanoparticles using Ziziphora clinopodioides Lam leaves under in vitro and in vivo condition

In recent decades, nanotechnology is growing rapidly owing to its widespread application in medical science. The aim of the experiment was the evaluation of cytotoxicity, antioxidant, antibacterial, antifungal, and cutaneous wound healing activities of green synthesized manganese nanoparticles using Ziziphora clinopodioides Lam leaves (MnNPs@ZC). The synthesized MnNPs@ZC were characterized using different techniques including UV–Vis., FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). According to the XRD analysis, 48.10 nm was measured for the crystal size of nanoparticles. SEM images exhibited a uniform spherical morphology and size in the range of 47.58 to 70.26 nm for the biosynthesized nanoparticles. MnNPs@ZC revealed excellent non-cytotoxicity effect against human umbilical vein endothelial cells, antioxidant activity against DPPH, antibacterial properties against Gram-negative bacteria (Salmonella typhimurium, Pseudomonas aeruginosa, and Escherichia coli O157:H7) and Gram-positive bacteria (Streptococcus pneumonia, Staphylococcus aureus, and Bacillus subtilis), and antifungal potentials against Candida glabrata, Candida albicans, Candida guilliermondii, and Candida krusei. Also, use of MnNPs@ZC ointment decreased significantly (p ≤ 0.01) the wound area, total cells, neutrophil, and lymphocyte and raised significantly (p ≤ 0.01) the wound contracture, hydroxyl proline, hexosamine, hexuronic acid, fibrocyte, and fibrocytes/fibroblast rate compared to other groups in experimental animals. In conclusion, synthesized MnNPs@ZC indicated antibacterial, antifungal, non-cytotoxicity, antioxidant, and cutaneous wound healing effects in a dose-depended manner. After confirming in the clinical trials, these nanoparticles can be used in human for the treatment of cutaneous and infectious diseases.     

Preparation and characterization of Cu (II) Schiff base complex functionalized boehmite nanoparticles and its application as an effective catalyst for oxidation of sulfides and thiols

The synthesis, characterization, and evaluation of a Schiff base Cu (II) complex functionalized boehmite nanoparticles (Cu-complex-boehmite) as a new catalyst for oxidation of sulfides and thiols in the presence of hydrogen peroxide with complete selectivity and high conversion under solvent-free and mild reaction conditions were reported. Characterization of the catalyst was performed with various physicochemical methods. This effective catalyst was evaluated in terms of activity and reusability. It indicated high catalytic activity, good recoverability and reusability, and supplied the corresponding products in high yields and short reaction times. In addition, it shows notable advantages such as simplicity of operation, heterogeneous nature, easy work up, and it could be used at least eight times with no significant loss of its activity.     

Green synthesis and chemical characterization of Thymus vulgaris leaf aqueous extract conjugated gold nanoparticles for the treatment of acute myeloid leukemia in comparison to doxorubicin in a leukemic mouse model

Recently, metallic nanoparticles have been used for the treatment of several disorders, such as cancer. Indeed, finding the chemotherapeutic drug of nanoparticles is in researching the priority of both developed and developing countries. The present study confirms the ability of aqueous extract of Thymus vulgaris grown under in vitro condition for the biosynthesis of gold nanoparticles (AuNPs). Also, in this study, we indicated the antioxidant, cytotoxicity, and anti-acute myeloid leukemia properties of AuNPs compared to doxorubicin in a leukemic mouse model. The synthesized AuNPs were characterized using different techniques including X-ray diffraction (XRD), energy Dispersive X-ray Spectrometry (EDS), fourier-transform infrared spectroscopy (FT-IR) spectroscopy, ultraviolet–visible spectroscopy (UV–Vis.), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). In vivo design, induction of acute myeloid leukemia was done by 7,12-Dimethylbenz[a]anthracene (DMBA) in 75 mice. Then, the animals were randomly divided into six subgroups, including control, untreated, doxorubicin, AuNPs, T. vulgaris, and HAuCl₄. By quantitative real-time PCR, sphingosine-1-phosphate receptor-1 and sphingosine-1-phosphate receptor-5 mRNA expression in lymphocytes were significantly (P ≤ 0.01) raised by treating the leukemic mice with the AuNPs and doxorubicin. Also, AuNPs similar to doxorubicin, significantly (P ≤ 0.01) enhanced the anti-inflammatory cytokines (IL4, IL5, IL10, IL13, and IFNα) and the platelet, lymphocyte, and red blood cell (RBC) parameters and reduced the pro-inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα), and the total white blood cell (WBC), blast, monocyte, neutrophil, eosinophil, and basophil counts as compared to the untreated mice. In vitro design, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test revealed similar antioxidant potentials for doxorubicin and AuNPs. Furthermore, AuNPs similar to doxorubicin had low cell viability dose-dependently against 32D-FLT3-ITD, Human HL-60/vcr, and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. Above results confirm the excellent antioxidant, cytotoxicity, and anti-acute myeloid leukemia effects of AuNPs compared to doxorubicin. After confirming these results in clinical trial studies, AuNPs can be used as a chemotherapeutic drug for the treatment of acute myeloid leukemia in human.