Construction and Hierarchical Self-Assembly of a Supramolecular Metal-Carbene Complex with Multifunctional Units.

Hierarchical combinations involving metal-ligand interactions and host-guest interactions can consolidate building blocks with unique functions into material properties. This study reports the construction and hierarchical self-assembly of multifunctional trinuclear AuI tricarbene complex containing three crown ether units and three ferrocene units. Host-guest interactions between the multifunctional trinuclear AuI tricarbene complex and organic ammonium salts were investigated, revealing that crown ether-based host-guest interactions can effectively regulate the electrochemical properties of the complex. Utilizing bisammonium salt as the cross-linker and multifunctional trinuclear AuI tricarbene complex as the core, a stimuli-responsive and self-healing supramolecular gel with different functional units was obtained.

A metal-carbene template approach enables efficient synthesis of a functionalized cage-annulated crown ether.

A facile synthetic method to form cage-annulated crown ether with anchored imidazolium units was developed. The present work verified the potential application of the metal-carbene template approach (MCTA) in the preparation of novel flexible polyimidazolium cages by photochemical [2+2] cycloaddition reactions and may provide a new method for the preparation of flexible pure organic cages with incorporation of a variety of functional sites.

N-Heterocyclic Carbene as a Surface Platform for Assembly of Homochiral Metal-Organic Framework Thin Films in Chiral Sensing.

N-heterocyclic carbenes (NHCs) have attracted increasing attention on surface assembly due to their strong metal binding property, but an NHC-modified metal surface as a new growth platform to assemble other functional materials is still a challenge. Here, we report the preparation and chiral sensing properties of homochiral metal-organic framework thin films on carboxyl-containing NHC self-assembled monolayer-modified gold (Au(NHC)) substrates. By using a liquid-phase epitaxial layer-by-layer method, enantiopure [Cu2(cam)2dabco]n thin films with preferred [110] crystal orientation have been successfully grown on Au(NHC) surfaces. The results of electrochemical cyclic voltammetry and quartz crystal microbalance uptakes of (R)- and (S)-1-phenylethanol show that the chiral porous thin film on the robust Au(NHC) surface has good enantiomeric electrochemical recognition and enantioselective adsorption. The present work is a new step to develop metal-NHCs as surface platforms for the preparation of multifunctional thin films for sensing applications.

A Comparative Analysis of Methods for Titering Reovirus.

BACKGROUND: A key challenge in the process of virus amplification is the need for a simple and convenient method for measuring virus titers. OBJECTIVE: Real-time unlabeled cell analysis (RTCA) was used to establish a standard curve of correlation between half-cell index time (CIT50) and virus titer. At the same time, the virus titer from tunable resistance pulse detection (TRPS) technology was compared with the traditional median tissue culture infectious dose (TCID50) method to evaluate the feasibility and application value of the RTCA technique and TRPS technology. METHODS: Cell index (CI) values for L929 cells under different culture conditions were detected, and the appropriate initial cell inoculation density was screened. The half-cell index (CI50) values of reovirus infected L929 cells with TCID50 titers were analyzed by RTCA, the CI50-TCID50 standard curve was created, and a regression equation was developed. RTCA, TCID50, and TRPS methods were used to detect the reovirus titer obtained by the amplification, and the sensitivity and feasibility of the CIT50-TCID50 standard curve method were analyzed. The virus titer was detected by TRPS technology and the TCID50 method. RESULTS: L929 cells were best propagated at an initial density of 6 × 103 cells/well. After infecting L929 cells with different titers of reference reovirus, the linear correlation of CIT50 and TCID50 was y = -2.1806x + 71.023 (R2 = 0.9742). The titer resulting from the RTCA assay was 7×109.6821 pfu/mL, from the TRPS assay was 4.52×1010 pfu/mL, and from the TCID50 assay was 7×109.467 pfu/mL. CONCLUSION: The CIT50-TCID50 standard curve method established by the RTCA technique can be used to quantitatively detect reovirus titer with L929 cells. Compared with the TCID50 method, it takes a relatively short time and has high sensitivity and accuracy. The TRPS technology requires even less time to quantify the virus, but its precision is lower than that of the TCID50 method and RTCA technology. This study provides new technical methods for assessing the virulence of infectious live reovirus particles. Lay Summary: After amplification of the virus, we need to detect the virus titers (the virulence of the virus). The traditional method is to use the virus to infect cells, and then the virus titers can be calculated by 50% of the cells infected. However, this traditional method is time consuming. The ways of RTCA (a real-time cell analysis technique) and TRPS (a nano-bioparticle analysis technique) help us to detect viral titers. The consistency of these three methods determines their feasibility and accuracy. If they are feasible, then these two simple technologies will provide new ideas for detecting viral titers.

[Effects of no-tillage, mulching, and organic fertilization on soil fungal community composition and diversity]. / å è€•è¦†ç›–åŠæœ‰æœºè‚¥æ–½ç”¨å¯¹åœŸå£¤çœŸèŒç¾¤è½ç»„æˆåŠå¤šæ ·æ€§çš„å½±å“.

We examined the responses of soil fungal community to no-tillage, mulching, and organic fertilization by setting up different treatments for three years in winter wheat land in mountain areas of southern Ningxia, including no-tillage, mulching and organic fertilization (NF), no-tillage, mulching and no organic fertilization (NC), conventional tillage without mulching and organic fertilization (TF), and conventional tillage without mulching and no organic fertilization (TC). Based on Illumina Miseq high-throughput sequencing platform, the relationship between the composition and diversity of soil fungal community and soil environmental factors were examined. A total of 3490 fungal OTUs were obtained from four treatments, which included some unidentified or unknown fungi. In the identified ones, Ascomycota and Basidiomycota were the dominant phylum, contributing to 82.1%-94.2% of the total abundance. The relative abundance of Dothideomycetes from Ascomycota was the highest under TF, while that of Tremellomycetes from Basidiomycota was highest under NF. Both Shannon and Simpson indices of soil fungal community were in order of NC>TC>NF>TF. The results of multivariate analysis showed that soil microbial biomass carbon was the main factor affecting the relative abundance of Basidiomycota and Zygomycotabased at the phylum level, while soil total phosphorus, available potassium, and available phosphorus were key factors driving the changes of relative abundance of Ascomycota. Therefore, popularizing of conservation tillage based on the no-tillage, mulching and organic fertilization technology would be beneficial to the diversity of soil fungal community in mountainou areas of southern Ningxia.

Backbone-Directed Self-Assembly of Interlocked Molecular Cyclic Metalla[3]Catenanes.

The efficient backbone-directed self-assembly of cyclic metalla[3]catenanes by the combination of tetrachloroperylenediimide (TCPDI)-based dinuclear rhodium(III) clips and 4,4'-diazopyridine or 4,4'-dipyridylethylene ligands is realized in a single-step strategy. The topology and coordination geometry of the cyclic metalla[3]catenanes are characterized by NMR spectroscopy, ESI-TOF-MS spectrometry, UV/Vis-NIR spectroscopy, and X-ray diffraction studies. The most remarkable feature of the formed cyclic metalla[3]catenane is that it contains π-aggregates (ca. 2.6 nm) incorporating six TCPDIs. Further studies revealed that cyclic metalla[3]catenanes can be converted reversibly to their corresponding sodium adducts and precursor building blocks, respectively. This strategy opens the possibility of generating unique supramolecular structures from discrete functional π-aggregates with precise arrangements.

Supramolecular Construction of a [16]-Imidazolium Cage via a Quadruple [2+2] Photocycloaddition and Its Selective Fluorescent Recognition of Pyranine (HPTS).

Polyimidazolium-based cages are considered promising materials based on their fascinating properties and potential applications. These three-dimensional functional structures are highly desirable for the recognition of particular guest molecules, however, their synthesis remains challenging. In this work, we have designed and synthesizes a pure [n]-imidazolium (n=16) cage, the hexadecakisimidazolium salt H16 -2(PF6 )16 , from tetragonal octakisimidazolium salt H8 -1(PF6 )8 . The synthetic method involves formation of metal-carbene templates, a quadruple photochemical [2+2] cycloaddition reaction and subsequent removal of metal ions. Specifically, the synthesized cage, featuring sixteen imidazolium moieties, demonstrated high efficiency for the selective fluorescent recognition of 8-hydroxy-1,3,6-pyrene trisulfonate (HPTS). The present work not only further develops the metal-carbene template strategy by exploiting a new type of polyimidazolium cage, but also provides encouraging prospects for the design of versatile imidazolium-based functional acceptors.

Strategy for the Construction of Diverse Poly-NHC-Derived Assemblies and Their Photoinduced Transformations.

A series of supramolecular assemblies of types [Ag8 (L)4 ](PF6 )8 and [Ag4 (L)2 ](PF6 )4 , obtained from the tetraphenylethylene (TPE) bridged tetrakis(1,2,4-triazolium) salts H4 -L(PF6 )4 and AgI ions, is described. The assembly type obtained dependends on the N-wingtip substituents of H4 -L(PF6 )4 . Changes in the lengths of the N4-wingtip substituents enables controlled formation of assemblies with either [Ag4 (L)2 ](PF6 )4 or [Ag8 (L)4 ](PF6 )8 stoichiometry. The molecular structures of selected [Ag8 (L)4 ](PF6 )8 and [Ag4 (L)2 ](PF6 )4 assemblies were determined by X-ray diffraction analyses. While H4 -L(PF6 )4 does not exhibit fluorescence in solution, their tetra-NHC (NHC=N-heterocyclic carbene) assemblies do upon NHC-metal coordination. Upon irradiation, all assemblies undergo a light-induced, supramolecule-to-supramolecule structural transformation by an oxidative photocyclization involving phenyl groups of the TPE core, resulting in a significant change of the luminescence properties.

[Effects of maize straw returning on arbuscular mycorrhizal fungal community structure in soil]. / çŽ‰ç±³ç§¸ç§†è¿˜ç”°å¯¹åœŸå£¤ä¸›æžèŒæ ¹çœŸèŒç¾¤è½çš„å½±å“.

To understand the effects of agricultural management activities on soil arbuscular mycorrhizal (AM) fungi diversity, the high-throughput sequencing based on Illumina MiSeq platform, and the fatty acids fingerprints were used to examine the effects of maize straw returning on soil arbuscular mycorrhizal fungi. The relationships between AM fungal community composition, AM fungal biomass and soil factors after maize straw returning were examined for four continuous years. A total of 2430 operational taxonomic units (OTUs) of AM fungi were classified into 10 genera and 143 species, respectively, which belonged to 1 phylum, 3 classes, 4 orders, 8 families. There was no significant difference in AM fungal community richness (Chaoles index and ACE index) and diversity (Shannon, Simpson diversity indices) in different treatments. Paraglomus and Glomus were dominant genera among all AM fungal communities. With the increase of the maize straw returned amounts, the abundance of Glomus reduced. Under the treatments of 3000 and 9000 kg·hm-2 straw returned, the abundance of Glomus and Acaulospora had significant differences with the control (0 kg·hm-2). Compared with the control, there were significant differences between Archaeospora, Paraglomus and Glomus in the treatment of 3000 kg·hm-2 straw returned. Results from non-metric multi-dimensional scale (NMDS) analysis showed that under 9000 and 12000 kg·hm-2 straw returning treatments, the difference between the ß diversity of soil AM fungi and the spatial distance of controls was farther apart than the other treatments. The effect of straw returning on the ß diversity of AM fungi was significant. The multivariate analysis results revealed the relationship of the spatial variation between the soil physicochemical properties and AM fungi richness and diversity could be explained at 82.8% cumulative variables. The total nitrogen and available nitrogen were the most important factors driving soil microbial communities biomass marked by PLFAs and AM fungal biomass (NLFAs). The continuous maize straw returning to the field changed the genera composition of AM fungi. With the increases of straw returning amounts, the specific species of AM fungi decreased and the similarity between AM fungi community composition decreased. Straw returning increased soil AM fungi biomass and its contribution to soil total microbial biomass.

BRCA1 affects the resistance and stemness of SKOV3-derived ovarian cancer stem cells by regulating autophagy.

Breast cancer 1 (BRCA1) and autophagy both play a significant role in drug resistance. However, little is known about the dynamic cross talk between BRCA1 and autophagy in the regulation of drug sensitivity. Here, we investigated the drug resistance-associated regulation of BRCA1 in epithelial ovarian cancer stem cells (EOCSCs). The results indicated that BRCA1 could regulate drug resistance in EOCSCs. Autophagy played a significant role in the stemness maintenance and was a key mechanism underlying the survival against chemotherapy in EOCSCs. Further investigation found that BRCA1 could regulate drug resistance of EOCSCs through autophagy. Meanwhile, changes in the level of autophagy provided feedback regarding the expression of BRCA1. Inhibition of autophagy activity could effectively reduce the resistance of EOCSCs caused by BRCA1. In addition, BRCA1 was able to regulate cellular apoptosis and cell cycle progression under the action of cisplatin through autophagy, indirectly affecting the drug sensitivity of EOCSCs. The present results highlight a novel relationship between BRCA1 and autophagy, which may provide insight into the etiology of BRCA1-associated ovarian cancer, and improve our understanding of resistance mechanisms in ovarian cancer.

Supramolecular Control of Photocycloadditions in Solution: In Situ Stereoselective Synthesis and Release of Cyclobutanes.

A new class of supramolecular metallacycles capable of undergoing photochemical reactions and in situ release of cyclobutanes in solution is described. The molecular metallacycles were generated through coordination-driven self-assembly of dinuclear metal-carbene complexes as organometallic clips with olefin-functionalized bridging ligands. Photolysis of these molecular metallacycles in situ led to structural interconversion and release of the formed cyclobutane products with quantitative conversion. Further modifications of the obtained cyclobutanes provided a series of new species containing the cyclobutane skeleton.

[Effect of intensive glucose control during peri-operative period on prognosis of patients undergoing cardiac surgery: a Meta-analysis].

OBJECTIVE: To systematically review the literature to determine the effects of intensive versus normal glycaemic control during peri-operative period on prognosis of patients undergoing cardiac surgery. METHODS: The literature was systematically reviewed based on searching criteria established by Cochrane Collaboration. PubMed database searching was conducted for literature and the language was limited to English. Each paper was reviewed by 2 independent reviewers and data extracted for statistical analysis. Data from identified studies were collected for Meta-analysis (RevMan 5.0). RESULTS: Seven randomized controlled trials (RCTs), involving a total of 2329 patients, were identified in the literature. The results showed that intensive glycaemic control could reduce the incidence of infection [odds ratio (OR) = 0.42, 95% confidence interval (95%CI) 0.25 to 0.73, P = 0.002], mortality (OR = 0.54, 95%CI 0.34 to 0.87, P = 0.01), the duration of mechanical ventilation [weighted mean difference (WMD) = -2.68, 95%CI -4.99 to -0.37, P = 0.02], and length of stay in the intensive care unit (ICU, WMD = -15.49, 95%CI -16.14 to -14.83, P < 0.000 01), and also could slightly reduce the incidence of post-surgical atrial fibrillation (OR = 0.77, 95%CI 0.60 to 1.00, P = 0.05). However, intensive glycaemic control could not reduce the use of epicardial pacing (OR = 0.32, 95%CI 0.09 to 1.05, P = 0.06). CONCLUSION: Intensive blood glucose control during peri-operative period could improve the prognosis of patients undergoing cardiac surgery.

[Mass chromatographic analysis on different protein expression of human periodontal ligament cell under static pressure].

PURPOSE: To analyze the protein expression of human periodontal ligament cells (HPDLCs) under static pressure. METHODS: The proteins of two groups of human periodontal ligament cell (one group was interfered by static pressure and one group was not) were analyzed by two-dimensional electrophoresis and mass chromatographic analysis. The silver stained proteins spots were analyzed by Image Master 2D Platinum Software 5.0. There were about 720 and 730 detectable spots on the two 2D-gels separately and nearly 30 spots which were differentially expressed. RESULTS: With direct MALDI-TOF mass spectrometry and protein database searching, 2 protein spots out of 5 new appeared spots were identified. Presenilin 2 and catechol O-methyltransferase were expressed only in the group which was interfered by static pressure. CONCLUSIONS: The results of mass chromatographic analysis demonstrate that Notch pathway and calcitonin gene-related peptide(CGRP) may be the partners of the channel of biomechanical signal conduction of the periodontal ligament cell.