1,965 research outputs found
2-{2,6-Bis[bis(4-fluorophenyl)methyl]-4-chlorophenylimino} -3-aryliminobutylnickel(II) bromide complexes: Synthesis, characterization, and investigation of their catalytic behavior
The series of 2-{2,6-bis[di(4-fluorophenyl)methyl]-4-chlorophenylimino}-3- aryliminobutane derivatives (L1-L5) and their nickel(II) dibromide complexes (Ni1-Ni5) were synthesized, and all organic compounds were fully characterized by the Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy and by elemental analysis, while the nickel complexes were characterized by FT-IR spectroscopy, elemental analysis, as well as by single-crystal X-ray diffraction for two representative examples, namely Ni1 and Ni4. A distorted tetrahedral geometry was observed for these four-coordinate nickel complexes. Upon the activation with either Methylaluminoxane or modified methylaluminoxane as co-catalyst, all nickel complex precatalysts showed very high activity toward ethylene polymerization with activities of up to 10 7 g(PE)·mol -1 (Ni)·h -1 , and afforded highly branched polyethylene with a bimodal distribution. © 2014 Elsevier B.V
Radioprotective effect and other biological benefits associated with flavonoids
Ionizing radiation has the potential to cause extensive damage to living organisms. It can directly act on DNA, proteins and lipids, resulting in ionizing excitation and chemical bond cleavage, which can lead to molecular and cellular damage. Ionizing radiation can hydrolyze water molecules in the body, resulting in increased numbers of free radicals with strong oxidation ability. This process indirectly leads to tissue degeneration and necrosis, which can possibly result in cancer. In this paper, the intervention mechanism of flavonoids on ionizing radiation was analyzed. It has been revealed that the intervention mechanism associated with flavonoids may offer protective properties for DNA, prevent scavenging free radicals, and protect against auto-immune damage. In addition, this invention mechanism can protect the hematopoietic system and reduce inflammationKeywords: Ionizing radiation, Flavonoids, Radioprotective mechanisms, Molecular and cellular damage, DNA, Hematopoietic system, Inflammatio
Synthesis, Structural Characterization,DFT,Hirschfeld Surface and Catalytic Activity of a New Zn (II) Complex of 4-Acetylbenzoic Acid
A new Zn(II) complex of 4-acetylbenzoic acid, namely [ZnL2(H2O)2] (1) (HL = 4-acetylbenzoic acid) has been synthesized in water-ethanol (v:v = 1:2) solution using zinc acetate dihydrate, 4-acetylbenzoic acid, and NaOH as reactants. The structure of complex (1) has been characterized by IR and X-ray single-crystal diffraction. X-ray diffraction analysis of complex (1) reveals that the Zn(II) ion is six-coordinated in a distorted octahedral coordination geometry with four carboxylic O atoms from two different bidentate 4-acetylbenzoic acid ligands (O1, O2, O1a, O2a) and two O atoms from two coordinated water molecules (O4 and O4a). Complex (1) forms 1D chained structure by the intermolecular and intramolecular O-H···O hydrogen bonds, and further forms a three-dimensional network structure by the π-π interaction of benzene rings and intermolecular O-H···O hydrogen bonds. The singlet ground-state geometry of the complex (1) were optimized using the PBE0 functional. The intermolecular interactions of complex (1) were quantitatively analysed by 3D Hirschfeld surface analysis and associated 2D fingerprint plots. The catalytic activity of complex (1) has been tested for the oxidation of benzyl alcohol under O2 atmosphere. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
2,2,7,7-Tetramethyl-1,2,3,6,7,8-hexahydrocinnolino[5,4,3-cde]cinnoline
The asymmetric unit of the title compound, C16H20N4, contains two half-molecules, which are completed by crystallographic inversion symmetry. The pyridazine rings are conjugated and the cyclohexane rings adopt envelope conformations
Constrained anti-disturbance control for a quadrotor based on differential flatness
The classical control design based on linearised model is widely used in practice even to those inherently nonlinear systems. Although linear design techniques are relatively mature and enjoy the simple structure in implementations, they can be prone to misbehaviour and failure when the system state is far away from the operating point. To avoid the drawbacks and exploit the advantages of linear design methods while
tackling the system nonlinearity, a hybrid control structure is developed in this paper. First, the model predictive control is used to impose states and inputs constraints on the linearised model, which makes the linearisation satisfy the small-perturbation requirement and reduces the bound of linearisation error. On the other hand, a combination of disturbance observer based control and H1 control, called composite hierarchical anti-disturbance control, is constructed for the linear model to provide robustness against multiple disturbances. The constrained reference states and inputs generated by the outer-loop model predictive controller are asymptotically tracked by the inner-loop composite anti-disturbance controller.
To demonstrate the performance of the proposed framework, a case study on quadrotor is conducted
Flight control design for small-scale helicopter using disturbance observer based backstepping
Flight control design for small-scale helicopter using disturbance observer based backsteppin
Antibody-drug conjugates targeting HER2 for the treatment of urothelial carcinoma: potential therapies for HER2-positive urothelial carcinoma
Urothelial carcinoma (UC) is a common cancer characterized by high morbidity and mortality rates. Despite advancements in treatment, challenges such as recurrence and low response rates persist. Antibody-drug conjugates (ADCs) have emerged as a promising therapeutic approach for various cancers, although their application in UC is currently limited. This review focuses on recent research regarding ADCs designed to treat UC by targeting human epidermal growth factor receptor 2 (HER2), a surface antigen expressed on tumor cells. ADCs comprise three main components: an antibody, a linker, and a cytotoxic payload. The antibody selectively binds to tumor cell surface antigens, facilitating targeted delivery of the cytotoxic drug, while linkers play a crucial role in ensuring stability and controlled release of the payload. Cleavable linkers release the drug within tumor cells, while non-cleavable linkers ensure stability during circulation. The cytotoxic payload exerts its antitumor effect by disrupting cellular pathways. HER2 is commonly overexpressed in UCs, making it a potential therapeutic target. Several ADCs targeting HER2 have been approved for cancer treatment, but their use in UC is still being tested. Numerous HER2 ADCs have demonstrated significant growth inhibition and induction of apoptosis in translational models of HER2-overexpressing bladder cancer. Ongoing clinical trials are assessing the efficacy and safety of ADCs targeting HER2 in UC, with the aim of determining tumor response and the potential of ADCs as a treatment option for UC patients. The development of effective therapies with improved response rates and long-term effectiveness is crucial for advanced and metastatic UC. ADCs targeting HER2 show promise in this regard and merit further investigation for UC treatment
Expression and prognostic significance of Golgiglycoprotein73 (GP73) with Epithelial-mesenchymal transition (EMT) related molecules in Hepatocellular Carcinoma (HCC)
BACKGROUND: Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third cause of cancer-related deaths, worldwide. It is essential to develop an effective prognostic biomarker and determine the mechanisms underlying HCC invasion and metastasis. AIMS: This study aimed to investigate the expression of Golgi glycoprotein73 (GP73) and Epithelial-mesenchymal transition (EMT) molecules such as E-cadherin and Vimentin in HCC. We also evaluated the prognostic value of GP73 in HCC. METHODS: Immunohistochemistry (IHC) was used to determine the expression of GP73 and EMT molecules in 75 HCC specimens and the corresponding paracarcinomatous liver (PCL) tissues. Spearman’s correlation test was used to analyze the correlation of GP73 and EMT molecules. Clinicopathological features of the HCC patients were also analyzed. Univariate survival analysis was performed by the Kaplan–Meier method and differences among the groups were analyzed by the Log-rank test. RESULTS: GP73 expression in HCC was higher compared with PCL tissues (χ( 2 ) = 73.60, P < 0.05). EMT molecules were also detected in HCC and PCL tissues. GP73 was negatively correlated with E-cadherin (r = − 0.49, P < 0.05), but positively correlated with Vimentin (r = 0.46, P < 0.05) in HCC. GP73 was correlated with the clinicopathological features including Edmondson grade, vascular invasion and TNM stage (P < 0.05), which was also associated with overall survival (OS) (P < 0.05). CONCLUSIONS: GP73 was negatively with E-cadherin and positively correlated with Vimentin. It might be associated with aggressive behavior of HCC and had influence on patients’ OS. Further research is needed to determine the potential of GP73. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/29 vs/1504046946108618; http://med.motic.com/MoticGallery/Slide?id=3b6a037e-f60e-4c68-9106-41e790de9431&user=2C69F0D6-A478-4A2B-ABF0-BB36763E8025; http://med.motic.com/MoticGallery/Slide?id=a25b5b32-b613-47b0-9f8b-e1e67a95d1bf&user=2C69F0D6-A478-4A2B-ABF0-BB36763E8025
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