Protein‐Affinitive Polydopamine Nanoparticles as an Efficient Surface Modification Strategy for Versatile Porous Scaffolds Enhancing Tissue Regeneration

Porous scaffolds for tissue regeneration are often functionalized with extracellular matrix proteins to enhance surface/cell interactions and tissue regeneration. However, continuous coatings produced by commonly used surface modification strategies may preclude cells from contacting and sensing the chemical and physical cues of the scaffold. Here, it is shown that polydopamine nanoparticles (PDA‐NPs) tightly adhere on various scaffolds to form nanostructures, and the coverage can be finely tuned. Furthermore, the PDA‐NPs have good affinity to a variety of proteins and peptides. Thus, the PDA‐NPs act as an anchor to immobilize signal biomolecules on scaffolds, and consequently promote cell activity and tissue regeneration. β‐Tricalcium phosphate (TCP) scaffolds decorated with PDA‐NPs demonstrate excellent osteoinductivity and bone‐regeneration performance due to the protein affinity of PDA‐NPs and the intrinsic bioactive characteristics of TCP scaffolds. In summary, PDA‐NPs with excellent affinity for protein adhesion represent a versatile platform to modify porous scaffolds while not compromising the biological functions of the scaffolds, and might have potential applications in tissue regeneration.     

Aminopropyl-grafted various silica mesostructures for adsorption of molybdenum ions from Re-containing effluent

Four different silica mesostructures, SBA-15 with mesopore size (8.5 nm), SBA-15 with mesopore size (10.3 nm), mesocellular foam (MCF) with uniform cell size (33.2 nm), and MCF with bimodal mesoporosity, were grafted with aminopropyl groups and used for selective recovery of Mo(VI) from Re(VII)-containing effluent. Adsorption isotherms and mechanism of Mo(VI) adsorption on these materials were studied. The adsorbed complexes of Mo(VI) could be formed by ion exchange process or/and by chelation reaction. This study shows a new approach for fractional recovery and separation of Mo(VI) from Re(VII) by using amino-modified SBA-15-type mesoporous silica.     

Copper‐Catalyzed Intramolecular Oxidative Amination of Unactivated Internal Alkenes

A copper‐catalyzed oxidative amination of unactivated internal alkenes has been developed. The Wacker‐type oxidative alkene amination reaction is traditionally catalyzed by a palladium through a mechanism involving aminopalladation and β‐hydride elimination. Replacing the precious and scarce palladium with a cheap and abundant copper for this transformation has been challenging because of the difficulty associated with the aminocupration of internal alkenes. The combination of a simple copper salt, without additional ligand, as the catalyst and Dess–Martin periodinane as the oxidant, promotes efficiently the oxidative amination of allylic carbamates and ureas bearing di‐ and trisubstituted alkenes leading to oxazolidinones and imidazolidinones. Preliminary mechanistic studies suggested a hybrid radical–organometallic mechanism involving an amidyl radical cyclization to form the key C?N bond.     

Organocatalytic,Asymmetric Total Synthesis of (−)‐Haliclonin A

The first total synthesis of the alkaloid (−)‐haliclonin A is reported. The asymmetric synthesis relied on a novel organocatalytic asymmetric conjugate addition of nitromethane with 3‐alkenyl cyclohex‐2‐enone to set the stereochemistry of the all‐carbon quaternary stereogenic center. The synthesis also features a Pd‐promoted cyclization to form the 3‐azabicyclo[3,3,1]nonane core, a SmI₂‐mediated intermolecular reductive coupling of enone with aldehyde to form the requisite secondary chiral alcohol, ring‐closing alkene and alkyne metathesis reactions to build the two aza‐macrocyclic ring systems, and an unprecedented direct transformation of enol into enone.     

Novel and potent Lewis acid catalyst: Br2-catalyzed Friedel–Crafts reactions of naphthols with aldehydes

A discovery that the inexpensive Br₂ can serve as a potent Lewis acid catalyst for bis(2-hydroxy-1-naphthyl)methanes synthesis is presented. Under the catalysis of Br₂ at room temperature, naphthols reacted smoothly with various aldehydes with high efficiency and broad substrate scope. This reaction used to require highly acidic conditions and/or high temperature and/or pressure, and sometimes featured poor yields. Moreover, theoretical calculations suggested that Br₂ is a potent Lewis acid to activate the carbonyl group, yet it was not the primary cause for the remarkable activity of Br₂ in the current communication.     

Improved PHSS iterative methods for solving saddle point problems

An improvement on a generalized preconditioned Hermitian and skew-Hermitian splitting method (GPHSS), originally presented by Pan and Wang (J. Numer. Methods Comput. Appl. 32, 174–182, 2011), for saddle point problems, is proposed in this paper and referred to as IGPHSS for simplicity. After adding a matrix to the coefficient matrix on two sides of first equation of the GPHSS iterative scheme, both the number of required iterations for convergence and the computational time are significantly decreased. The convergence analysis is provided here. As saddle point problems are indefinite systems, the Conjugate Gradient method is unsuitable for them. The IGPHSS is compared with Gauss-Seidel, which requires partial pivoting due to some zero diagonal entries, Uzawa and GPHSS methods. The numerical experiments show that the IGPHSS method is better than the original GPHSS and the other two relevant methods.     

<Emphasis Type="Italic">N</Emphasis>-(4-(quinazolin-2-yl)phenyl)benzamide derivatives with potent anti-angiogenesis activities: synthesis and evaluation

Expanding our studies on the anti-angiogenesis activities of 2,4-disubstituted quinazoline derivatives [8], a series of novel N-(2-(quinazolin-2-yl)phenyl)benzamide (SZ) derivatives were designed and synthesized. Cytotoxicity assays indicated that most of these compounds displayed similar cytotoxicity against tumor cells in comparison with our previously reported, but showed a higher cytotoxicity against HUVECs. The SZ derivatives showed a remarkable inhibitive effect against the migration and adhesion of HUVECs, in addition to demonstrating significant in vivo anti-angiogenesis activities in the chick embryo chorioallantoic membrane (CAM) assay. The results proved that the introduction of an aryl group with a basic amide side chain on the 4′ position linked to the amide of the C-2 substituted quinazoline scaffold is an effective approach to improve the anti-angiogenic activity of quinazoline derivatives.     

Magnetically separated and N,S co-doped mesoporous carbon microspheres for the removal of mercury ions

Magnetically separated and N, S co-doped mesoporous carbon microspheres (N/S-MCMs/Fe₃O₄) are fabricated by encapsulating SiO₂ nanoparticles within N, S-containing polymer microspheres which were prepared using resorcinol/formaldehyde as the carbon source and cysteine as the nitrogen and sulfur co-precursors, followed by the carbonization process, silica template removal, and the introduction of Fe₃O₄ into the carbon mesopores. N/S-MCMs/Fe₃O₄ exhibits an enhanced Hg²⁺ adsorption capacity of 74.5 mg/g, and the adsorbent can be conveniently and rapidly separated from wastewater using an externalmagnetic field. This study opens up new opportunities to synthesize welldeveloped, carbon-based materials as an adsorbent for potential applications in the removal of mercury ions from wastewater.