On perturbation bounds for orthogonal projections

In this paper, we present some new perturbation bounds for the orthogonal projections onto the column and row spaces of a matrix, which improve some existing results. Numerical examples are presented to illustrate our results.     

Amorphous High-Entropy Hydroxides of Tunable Wide Solar Absorption for Solar Water Evaporation

The high-entropy materials have raised much attention in recent years due to their extraordinary performances in mechanical, catalysis, energy storage fields. Herein, a new type of high-entropy hydroxides (e.g., NiFeCoMnAl(OH)_x) that are amorphous and capable of broad solar absorption is reported. A facile one-pot co-precipitation method is employed to synthesize these amorphous high-entropy hydroxides (a-HEHOs) under ambient conditions. The a-HEHOs thus obtained display widely tunable bandgap (e.g., from 2.6 to 1.1 eV) due to their high-entropy and amorphous characteristics, enabling efficient light absorbance and photothermal conversion in the solar regime. Further solar water evaporation measurements show that the a-HEHOs delivered a considerable energy conversion efficiency of 55%, comparable to black titanium oxides that are synthesized using more complex and expensive methods.     

A three-dimensional in vitro culture model for primary neonatal rat ventricular myocytes

To overcome bad prognosis of patients with heart failure and the lack of organ donors, cardiac tissue engineering has developed as a biomimetic approach to repair, replace, and regenerate the damaged cardiac tissue. During the past decade years, researchers are devoted to find different natural and/or synthetic materials that can build appropriate physical structures to contain and organize implanted cells. In this study, we present a new method for primary neonatal rat cardiomyocytes culture in vitro using alginate/collagen/chitosan hydrogel. To investigate the feasibility of this material as scaffold for cardiac myocytes, neonatal rat ventricular myocytes were isolated and encapsulated in alginate-based beads cross-linked with calcium ion. The growth of cells was evaluated by staining with α-Sarcomeric actin (α-SCA) and Troponin T type 2 (TNNT2), and the viability of cardiomyocytes was studied in vitro by assessing the expression levels of several cardiac ion channels, including CACNL1A1, Connexin 43 and SCN5A. The results showed a significant increase in cardiac myocytes number, and the expression levels of CACNL1A1, Connexin 43 (Cx43) were up-regulated significantly except SCN5A, as compared with two-dimensional cultures. Moreover, extracellular matrix produced by the seeded cells themselves was observed by staining with fibronectin. Taken together, these findings indicate that this alginate/collagen/chitosan hydrogel bead is suitable for supporting the growth and retaining the morphologic and electrophysiologic characteristics of primary cultured rat cardiac muscle cells.     

The enhanced biological activities of three Zn (II) complexes based on different 1,2,4‐triazole fungicides

In order to screen effective fungicides, three Zn (II) complexes, [Zn L ¹ ₄ (NO₃)₂]·2H₂O·2EtOH ( 1 ), [Zn L ² ₄ (NO₃)₂] ( 2 ), and [Zn L ³ ₄ (DMF)₂](NO₃)₂ ( 3 ), ( L ¹  = paclobutrazol, L ²  = diniconazole, and L ³  = hexaconazole), were synthesized and characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal XRD. The antifungal activities of these complexes were then evaluated against four selected fungi using the mycelial growth rate method. The resulting data indicate that all the complexes show the enhanced antifungal activities than the corresponding ligand and mixtures. And, the interactions between the metal salt and ligands in the three complexes seem to be synergistic. According to the study of the influence of the structures on the activity, complex 2 with C=C linkage and 2,4‐dichlorophenyl moieties enhances the bioactivity significantly, especially against Wheat gibberellic ( II ). Density functional theory (DFT) calculations were carried out to help explain the enhanced bioactivity of the Zn (II) complexes. Meanwhile, all complexes are excellent grow‐regulators, especially complex 3 . The resulting data show that the complexes based on triazole fungicides have the potential applications in agriculture.     

Enhanced photocatalytic activity of hybrid reduced graphene oxide–CeO2 hierarchical flower-like nanostructures

Research on Chemical Intermediates - The combination of the unique properties of graphene with functional characteristics of metal oxides is an interesting pathway to achieve desirable properties...     

Catalyst‐Free Protocol for the Synthesis of Quinoxalines and Pyrazines in PEG

A facile and simple catalyst‐free protocol has been developed for the condensation of 1,2‐diketones with aromatic 1,2‐diamines in polyethylene glycol (PEG), providing quinoxaline derivatives in good yields. The important features of the methodology are broad substrates scope, simple workup, catalyst free, environmentally benign, and no requirement for metal catalysts. It is noteworthy that the cyclization reaction of 1,2‐diketones with aliphatic 1,2‐diamines is also conducted smoothly to afford pyrazines in good yields under the standard conditions. In addition, PEG could be recovered easily and was reused without evident loss in activity     

Computational insight into asymmetric uranyl‐salophen coordinated with α, β‐unsaturated aldehydes and ketones

The study of the catalytic activity and activation mechanism of asymmetric uranyl‐salophens with α, β‐unsaturated aldehydes or α, β‐unsaturated ketones, is a research hotspot. In this paper, the complexes of the uranyl–salophen(U‐S) modified by unilateral benzene, coordinated with cyclohexenone, cyclopentenone and acrolein, were investigated using density functional theory calculations at the level of B3LYP/6‐311G(d, p) basis set. The results showed that the uranyl‐salophen(U‐S) weakened the large π bond between C = C and C = O of the α, β‐unsaturated aldehydes and ketones, making the unsaturated aldehydes and ketones activated. In addition, the molecular‐recognition selectivity of the asymmetrical uranyl‐salophen for cyclohexenone and cyclopentenone were much higher than for acrolein.     

Solvothermal synthesis of PbTe/SnTe hybrid nanocrystals

PbTe/SnTe hybrid nanocrystals with designed shape, chemical composition and narrow size distribution were synthesized by an efficient solvothermal approach. This approach enables mass and economical synthesis of PbTe-based nanocrystals. The organic ligands were completely removed by pretreatment with a super-hydride solution, making it possible to fabricate fully dense and robust thermoelectric devices with increased electrical conductivity.