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In the last decade, graphene has been frequently cited as one of the most promising materials for nanoelectronics. However, despite its outstanding mechanical and electronic properties, its use in the production of real nanoelectronic devices usually imposes some practical difficulties. This happens mainly due to the fact that, in its pristine form, graphene is a gapless material. We investigate theoretically the possibility of obtaining rectifying nanodevices using another carbon based two dimensional material, namely the graphenylene. This material has the advantage of being an intrinsic semiconductor, posing as a promising material for nanoelectronics. By doping graphenylene, one could obtain 2-dimensional p-n junctions, which can be useful for the construction of low dimensional electronic devices. We propose 2-dimensional diodes in which a clear rectification effect was demonstrated, with a conducting threshold of approximately 1.5 eV in direct bias and current blocking with opposite bias. During these investigations were found specific configurations that could result in devices with Zener-like behavior. Also, one unexpected effect was identified, which was the existence of transmission dips in electronic conductance plots. This result is discussed as a related feature to what was found in graphene nanoribbon systems under external magnetic fields, even though the external field was not a necessary ingredient to obtain such effect in the present case.A novel dearomatization/rearomatization/cyclization oxonium ylide trapping process is well developed via a dirhodium(ii) acetate and phosphoric acid cooperatively catalyzed multi-component reaction of diazo-ketones with alcohols and azonaphthalenes. This protocol provides an efficient route to synthesize N-substituted 1-amino-indole derivatives in good yield under mild reaction conditions.Topoisomerases are ubiquitous enzymes and important targets for DNA-oriented anticancer drugs. Two mitochondrion-targeted monofunctional platinum(ii) complexes, [Pt(ortho-PPh3CH2Py)(NH3)2Cl](NO3)2 (OPT) and [Pt(para-PPh3CH2Py)(NH3)2Cl](NO3)2 (PPT; PPh3 = triphenylphosphonium, Py = pyridine), show significant inhibition towards the activity of DNA topoisomerases in addition to their DNA binding and mitochondrial targeting capabilities. OPT exhibits strong cytotoxicity toward the human renal clear cell carcinoma 786-O and the murine prostate cancer RM-1 cell lines. The complex could bind to the minor groove of DNA, as well as DNA topoisomerases I and IIα, thereby acting as an inhibitor of topoisomerase I/IIα and causing DNA damage. The damage was evidenced by the enhanced expression of γ-H2AX, Chk1/2 phosphorylation, p53 and cell cycle arrest in the G2/M phase. In contrast, the inhibitory effect of PPT on DNA topoisomerases was largely limited to the isolated enzymes. The results demonstrate that the cellular inhibition of the complex towards the DNA topoisomerases positively correlated with its mitochondrial accumulation. Molecular docking provided more detailed structural insights into the interactions of OPT or PPT with DNA and topoisomerase I/IIα. The binding sites of OPT and PPT in topoisomerase-DNA complexes are different from each other. Aside from previously revealed DNA and mitochondrial targets, this study discovered new evidence that DNA topoisomerases may also serve as targets of monofunctional platinum(ii) complexes. For a multispecific platinum complex, strong DNA binding ability does not necessarily lead to potent cytotoxicity as other factors including the cell types, mitochondrial accumulation, and activity of DNA topoisomerases also affect the outcome of DNA damage.Recently, near-infrared phosphors that can be applied in many fields such as night vision, agriculture, and bio-applications have attracted considerable interest in the research field worldwide. Herein, a multi-functional and dual-excited near-infrared phosphor Mg14Ge5O24Cr3+,Cr4+ which provides two emission bands ranging from 700 nm to 1100 nm and 1100 nm to 1700 nm has been obtained via the traditional high-temperature solid state reaction. https://www.selleckchem.com/products/me-401.html The presence of six and four coordination ions in the olivine structure of Mg14Ge5O24 provides a favorable environment for the coexistence of Cr3+ and Cr4+. Under blue light excitation, a super broad emission band ranging from 650 nm to 1100 nm with a full-width at half maximum (FWHM) of 266 nm is assigned to the spin-allowed 4T2 (4F) →4A2 transition of Cr3+ in a weak crystal-field environment. With the increase in the concentration of Cr ions, more and more Cr4+ preferentially occupies four coordinated Ge4+ sites, and the other broad emission band ranging from 1100 nm to 1600 nm with a FWHM of 256 nm that comes from the 3T2→3A2 transition of Cr4+ is observed. The phenomenon of NIR I region excitation and NIR II region emission appears. The transmission experiment of a biological tissue proves that the Mg14Ge5O24Cr3+,Cr4+ phosphor has potential applications in the field of near-infrared light-emitting diodes for biological detection.Tryptophan enantiomers (d/l-Trp) were introduced into artificial nanochannels to regulate the chiral selective transport of Aβ proteins. The l-Trp channel performs effectively selectivity for the transport of Aβ protein, which would provide a new perspective for the pathological studies of Alzheimer's disease.Covering 2005 up to 2020Olive bioactive secoiridoids are recognized as natural antioxidants with multiple beneficial effects on human health. Nevertheless, the study of their biological activity has also disclosed some critical aspects associated with their application. Firstly, only a few of them can be extracted in large amounts from their natural matrix, namely olive leaves, drupes, oil and olive mill wastewater. Secondly, their application as preventive agents and drugs is limited by their low membrane permeability. Thirdly, the study of their biological fate after administration is complicated by the absence of pure analytical standards. Accordingly, efficient synthetic methods to obtain natural and non-natural bioactive phenol derivatives have been developed. Among them, semi-synthetic protocols represent efficient and economical alternatives to total synthesis, combining efficient extraction protocols with efficient catalytic conversions to achieve reasonable amounts of active molecules. The aim of this review is to summarize the semi-synthetic protocols published in the last fifteen years, covering 2005 up to 2020, which can produce natural olive bioactive phenols scarcely available by extractive procedures, and new biophenol derivatives with enhanced biological activity. Moreover, the semi-synthetic protocols to produce olive bioactive phenol derivatives as analytical standards are also discussed. A critical analysis of the advantages offered by semi-synthesis compared to classical extraction methods or total synthesis protocols is also performed.In this Feature Article, we summarize the synthetic progress of hetero[8]circulenes, focusing on their structures and intrinsic properties. Various hetero[8]circulenes have been synthesized to date, of which structural features are categorized on the basis of the numbers of annulated pentagons. From the viewpoint of key steps, the synthetic routes are classified into two methodologies, the annulative construction of the central eight-membered ring and the ring fusion of eight-membered ring precursors. Electronic and photophysical properties based on the structural features and the introduced heteroatoms of hetero[8]circulenes are also described.Nanocomposite double-network hydrogels (ncDN hydrogels) are recently introduced to address the limitations of traditional DN hydrogels, such as the lack of diversity in the network structure and the restricted functionalities. However, two challenges remain, including the time-consuming preparation and the lack of shear-thinning and self-healing properties. Here, our approach to developing versatile ncDN hydrogels is through the use of multiple interfacial crosslinking chemistries (i.e., noncovalent interactions of electrostatic interaction and hydrogen bonds as well as dynamic covalent interactions of imine bonds and boronate ester bonds) and surface functionalized nanomaterials (i.e. phenylboronic acid modified reduced graphene oxide (PBA-rGO)). PBA-rGO was used as a multivalent gelator to further crosslink the two polymer chains (i.e. triethylene glycol-grafted chitosan (TEG-CS) and polydextran aldehyde (PDA)) in DN hydrogels, forming the TEG-CS/PDA/PBA-rGO ncDN hydrogels in seconds. The microstructures (i.e. pore size) and properties (i.e. rheological, mechanical, and swelling properties) of the ncDN hydrogels can be simply modulated by changing the amount of PBA-rGO. The dynamic bonds in the polymeric network provided the shear-thinning and self-healing properties to the ncDN hydrogels, allowing the hydrogels to be injected and molded into varied shapes as well as self-repair the damaged structure. Besides, the designed TEG-CS/PDA/PBA-rGO ncDN hydrogels were cytocompatible and also exhibited antibacterial activity. Taken together, we hereby provide a nanomaterial approach to fabricate a new class of ncDN hydrogels with tailorable networks and favorite properties for specific applications.The imbalance between the anabolism and catabolism of the extracellular matrix (ECM) is of great importance to osteoarthritis (OA) development. Aberrant inflammatory responses and hypertrophic changes of chondrocytes are the main contributors to these metabolic disorders. In the present study, we found that Oroxylin A (ORA), a flavonoid compound derived from Oroxylum indicum, maintained ECM hemostasis of chondrocytes by Interleukin-1β (IL-1β) stimulation. Besides, it was demonstrated that IL-1β induced over-production of inflammatory mediators was attenuated by ORA treatment. Moreover, ORA could rescue IL-1β mediated hypertrophic alterations of chondrocytes. Mechanistically, ORA's protective effects were found to be associated with both NF-κB and Wnt/β-catenin signaling inhibition. Meanwhile, molecular docking analysis revealed that ORA could strongly bind to the inhibitor kappa B kinaseβ (IKKβ) and dishevelled, Dsh Homolog 2 (Dvl2), the upstream molecules of the NF-κB axis and β-catenin axis, respectively. In addition, ORA driven chondroprotective effects were also affirmed in a surgically induced OA mouse model. Taken together, the current study suggested that ORA might be a promising therapeutic option for the treatment of OA.Supersilyl, -Si(SiMe3)3, serves as an effective ligand to afford a series of four-coordinate manganese(ii) complexes. A dinuclear complex, [(THF)MnSi(SiMe3)3(μ-Br)]2 (2), was readily synthesized by the reaction of MnBr2 with KSi(SiMe3)3. A subsequent ligand exchange of Br in 2 to -OtBu, methyl, or hydride afforded the corresponding manganese(ii) complexes.Fluorescent organic nanoparticles (FONPs) have attracted considerable attention as a practical and effective platform for sensing and imaging applications. The present article delineates the fabrication of FONPs derived from the naphthalimide based histidine appended amphiphile, NID. The self-assembly of NID in 99 vol% water in DMSO led to the formation of FONPs through J-type aggregation. Aggregation-induced emission (AIE) was observed due to the pre-associated excimer of NID with bluish green emission at 470 nm along with intramolecular charge transfer (ICT). The emission of NID FONPs was utilized for selective sensing of Fe3+ and bioimaging of Fe3+ inside mammalian cells. The fluorescence intensity of the FONPs was quenched with the gradual addition of Fe3+ due to the formation of a 1 1 stoichiometric complex with the histidine residue of NID. The morphology of the FONPs transformed from spherical to spindle upon the complex formation of NID with Fe3+. The limit of detection (LOD) of this AIE based turn-off chemosensor for Fe3+ was found to be 12.
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