Coupled effects of elevated CO2 and biochar on microbial communities of vegetated soil.

Soil microbial communities are important for plant growth and establishing healthy ecosystems. Although biochar is widely adopted as a sustainable fertilizer, its influence on soil ecological functions is still unclear, especially under climate change such as elevated carbon dioxide concentration (eCO2). This study explores the coupled effects between eCO2 and biochar on microbial communities in soil planted with tree seedlings of Schefflera heptaphylla. Root characteristics and soil microbial communities were examined and interpreted with statistical analysis. Results show that biochar application at ambient carbon dioxide concentration (aCO2) always improves plant growth, which is further promoted under eCO2. Similarly, ß-glucosidase, urease and phosphatase activities are enhanced by biochar at aCO2 (p < 0.05). In contrast, only urease activity increases with biochar added at eCO2 (p < 0.05). The beneficial effects of biochar on soil enzyme activities become less significant at eCO2. Depending on biochar type, biochar can increase bacterial diversity and fungal richness at aCO2. However, at eCO2, biochar does not significantly affect microbial richness (p > 0.05) while microbial diversity is reduced by peanut shell biochar (p < 0.05). Owing to better plant growth under biochar application and eCO2, plants are likely to become more dominant in specializing the microbial communities that are favourable to them. In such community, the abundance of Proteobacteria is the greatest and increases after biochar addition at eCO2. The most abundant fungus also shifts from Rozellomycota to Ascomycota and Basidiomycota. These microbes can improve soil fertility. Even though the microbial diversity is reduced, using biochar at eCO2 can further promote plant growth, which in turn enhances carbon sequestration. Thus, biochar application can be an effective strategy to facilitate ecological restoration under climate change and relieve the problem of eCO2.

Enhanced Photoelectrochemical Water Splitting of Black Silicon Photoanode with pH-Dependent Copper-Bipyridine Catalysts.

Since the water oxidation half-reaction requires the transfer of multi-electrons and the formation of O-O bond, it's crucial to investigate the catalytic behaviours of semiconductor photoanodes. In this work, a bio-inspired copper-bipyridine catalyst of Cu(dcbpy) is decorated on the nanoporous Si photoanode (black Si, b-Si). Under AM1.5G illumination, the b-Si/Cu(dcbpy) photoanode exhibits a high photocurrent density of 6.31 mA cm-2 at 1.5 VRHE at pH 11.0, which is dramatically improved from the b-Si photoanode (1.03 mA cm-2 ) and f-Si photoanode (0.0087 mA cm-2 ). Mechanism studies demonstrate that b-Si/Cu(dcbpy) has improved light-harvesting, interfacial charge-transfer, and surface area for water splitting. More interestingly, b-Si/Cu(dcbpy) exhibits a pH-dependent water oxidation behaviour with a minimum Tafel slope of 241 mV/dec and the lowest overpotential of 0.19 V at pH 11.0, which is due to the monomer/dimer equilibrium of copper catalyst. At pH ∼11, the formation of dimeric hydroxyl-complex could form O-O bond through a redox isomerization (RI) mechanism, which decreases the required potential for water oxidation. This in-depth understanding of pH-dependent water oxidation catalyst brings insights into the design of dimer water oxidation catalysts and efficient photoanodes for solar energy conversion.

Mitochondria-targeted Re(I) complexes bearing guanidinium as ligands and their anticancer activity.

As the "powerhouse" of a cell, mitochondria maintain energy homeostasis, synthesize ATP via oxidative phosphorylation, generate ROS signaling molecules, and modulate cell apoptosis. Herein, three Re(I) complexes bearing guanidinium derivatives have been synthesized and characterized. All of these complexes exhibit moderate anticancer activity in HepG2, HeLa, MCF-7, and A549 cancer cells. Mechanism studies indicate that complex 3, [Re(CO)3(L)(Im)](PF6)2, can selectively localize in the mitochondria and induce cancer cell death through mitochondria-associated pathways. In addition, complex 3 can effectively depress the ability of cell migration, cell invasion, and colony formation.

IL-11 drives the phenotypic transformation of tracheal epithelial cells and fibroblasts to enhance abnormal repair after tracheal injury.

Tracheal stenosis (TS) is a multifactorial and heterogeneous disease that can easily lead to respiratory failure and even death. Interleukin-11 (IL-11) has recently received increased attention as a fibrogenic factor, but its function in TS is uncertain. This study aimed to investigate the role of IL-11 in TS regulation based on clinical samples from patients with TS and a rat model of TS produced by nylon brush scraping. Using lentiviral vectors expressing shRNA (lentivirus-shRNA) targeting the IL-11 receptor (IL-11Rα), we lowered IL-11Rα levels in the rat trachea. Histological and immunostaining methods were used to evaluate the effects of IL-11Rα knockdown on tracheal injury, molecular phenotype, and fibrosis in TS rats. We show that IL-11 was significantly elevated in circulating serum and granulation tissue in patients with TS. In vitro, TGFß1 dose-dependently stimulated IL-11 secretion from human tracheal epithelial cells (Beas-2b) and primary rat tracheal fibroblasts (PRTF). IL-11 transformed the epithelial cell phenotype to the mesenchymal cell phenotype by activating the ß-catenin pathway. Furthermore, IL-11 activated the atypical ERK signaling pathway, stimulated fibroblasts proliferation, and transformed fibroblasts into alpha-smooth muscle actin (α-SMA) positive myofibroblasts. IL-11-neutralizing antibodies (IL-11NAb) or ERK inhibitors (U0126) inhibited IL-11 activity and downregulated fibrotic responses involving TGFß/SMAD signaling. In vivo, IL-11Rα knockdown rats showed unobstructed tracheal lumen, relatively intact epithelial structure, and significantly reduced granulation tissue proliferation and collagen fiber deposition. Our findings confirm that IL-11 may be a target for future drug prevention and treatment of tracheal stenosis.

Chitosan derivatives functionalized dual ROS-responsive nanocarriers to enhance synergistic oxidation-chemotherapy.

The efficient triggering of prodrug release has become a challengeable task for stimuli-responsive nanomedicine utilized in cancer therapy due to the subtle differences between normal and tumor tissues and heterogeneity. In this work, a dual ROS-responsive nanocarriers with the ability to self-regulate the ROS level was constructed, which could gradually respond to the endogenous ROS to achieve effective, hierarchical and specific drug release in cancer cells. In brief, DOX was conjugated with MSNs via thioketal bonds and loaded with ß-Lapachone. TPP modified chitosan was then coated to fabricate nanocarriers for mitochondria-specific delivery. The resultant nanocarriers respond to the endogenous ROS and release Lap specifically in cancer cells. Subsequently, the released Lap self-regulated the ROS level, resulting in the specific DOX release and mitochondrial damage in situ, enhancing synergistic oxidation-chemotherapy. The tumor inhibition Ratio was achieved to 78.49%. The multi-functional platform provides a novel remote drug delivery system in vivo.

Lysosome-targeted ruthenium(II) complexes induce both apoptosis and autophagy in HeLa cells.

Ruthenium complexes with good biological properties have attracted increasing attention in recent decades. In this work, three ruthenium polypyridine complexes containing 5-fluorouracil derivatives as ligands, [Ru(bpy)2(L)]2+ (Ru1), [Ru(phen)2(L)]2+ (Ru2), [Ru(dip)2(L)]2+ (Ru3) (L = 1-((1,10-phenanthroline-5-amino) pentyl)-5-fluorouracil; bpy = 2,2'-bipyridine; phen =1,10-phenanthroline; dip = 4,7-diphenyl-1,10-phenanthroline), were synthesized and characterized. Based on in vitro cytotoxicity tests, Ru3 (IC50 = 7.35 ± 0.39 µM) showed the best anticancer activity among three compounds in the selected cell lines. It is worth noting that Ru3 also exerts less cytotoxicity on LO2 cell lines, with an IC50 value 5 times higher than that on HeLa cells, indicating its selective activity. Mechanism studies revealed that Ru3 can specifically target lysosomes and induce cell apoptosis in a caspase-dependent manner. Specifically, Ru3 can arrest cell cycle at the G0/G1 phase, increase the intracellular reactive oxygen species (ROS) level, and then damage DNA. In short, Ru3 can eventually cause cell death through the synergy of inducing apoptosis and autophagy, which was further proven by western blot assay results.

Rhenium-guanidine complex as photosensitizer: trigger HeLa cell apoptosis through death receptor-mediated, mitochondria-mediated, and cell cycle arrest pathways.

The growing evidence over the past few decades has indicated that the photodynamic antitumor activity of transition metal complexes, and Re(I) compounds are potential candidates for photodynamic therapy. This study reports the synthesis, characterization, and anti-tumor activity of three new Re(I)-guadinium complexes. Cytotoxicity tests reveal that complex Re1 increased cytotoxicity by 145-fold from IC50 > 180 µM in the dark to 1.3 ± 0.7 µM following 10 min of light irradiation (425 nm) in HeLa cells. Further, the mechanism by which Re1 induces apoptosis in the presence or absence of light irradiation was investigated, and results indicate that cell death was caused through different pathways. Upon irradiation, Re1 first accumulates on the cell membrane and interacts with death receptors to activate the extrinsic death receptor-mediated signaling pathway, and then is transported into the cell cytoplasm. Most of the intracellular Re1 locates within mitochondria, improving the reactive oxygen species level, and decreasing mitochondrial membrane potential and ATP levels, and inducing the activation of caspase-9 and, thus, apoptosis. Subsequently, the residual Re1 can translocate into the cell nucleus, and activates the p53 pathway, causing cell cycle arrest and eventually cell death.

Cyclometalated iridium(III) complexes as mitochondria-targeted anticancer and antibacterial agents to induce both autophagy and apoptosis.

Mitochondrial damage will hinder the energy production of cells and produce excessive ROS (reactive oxygen species), resulting in cell death through autophagy or apoptosis. In this paper, four cyclometalated iridium(III) complexes (Ir1: [Ir(piq)2L]PF6; Ir2: [Ir(bzq)2L]PF6; Ir3: [Ir(dfppy)2L]PF6; Ir4: [Ir(thpy)2L]PF6; piq = 1-phenylisoquinoline; bzq = benzo[h]quinoline; dfppy = 2-(2,4-difluorophenyl)pyridine;thpy = 2-(2-thienyl)pyridine; L = 1,10-phenanthroline-5-amine) were synthesized and characterized. Cytotoxicity tests show that these complexes have excellent cytotoxicity to cancer cells, and mechanism studies indicatethat these complexes can specifically target mitochondria. Complexes Ir1 and Ir2 can damage the function of mitochondria, subsequently increasing intracellular levels of ROS, decreasing MMP (mitochondrial membrane potential), and interfering with ATP energy production, which leads to autophagy and apoptosis. Furthermore, autophagy induced by Ir1 and Ir2 can promote cell death in coordination with apoptosis. Surprisingly, these four complexes also showed moderate antibacterial activity to S. aureusand P. aeruginosa.

Dual-responsive TPGS crosslinked nanocarriers to overcome multidrug resistance.

Efficient delivery of chemotherapeutic agents into tumor cells and reversal of chemoresistance are crucially important to enhance cancer therapy. We fabricated pH/redox dual responsive nanocarriers based on cell penetrating peptides (TAT) functionalized TPGS (cTAT-TPGS) and polypeptide (PEG-b-poly(aspartic-lipoic acid), PPAL) to reduce the permanent drug release and overcome multidrug resistance. TAT was used to functionalize TPGS and shielded by pH-responsive fatty acids, and polypeptides with lipoic acid side chains (PPAL) were synthesized. Reversibly crosslinked hybrid micelles (RCMs) were fabricated based on cTAT-TPGS and PPAL. RCMs nanocarriers exhibited acid-responsive charge reversal and redox-responsive drug release. The in vitro results showed that the RCMs could be efficiently internalized by the MCF-7/ADR cells in an acidic microenvironment and inhibited the DOX efflux, causing a higher cytotoxicity than non-crosslinked nanocarriers. Furthermore, the dual-responsive structure effectively prolonged the circulation time of RCM nanocarriers and achieved a high level of accumulation in cancer cells in vivo, leading to much more effective inhibition of tumor growth. The DOX-loaded RCMs also showed excellent biosafety, especially for the myocardium tissue. This novel strategy provided an effective platform for drug target delivery and reversal of MDR.

Synthesis of methionine methyl ester-modified coumarin as the fluorescent-colorimetric chemosensor for selective detection Cu2+ with application in molecular logic gate.

A methionine methyl ester-modified coumarin derivative was designed and synthesized, which could discriminate Cu2+ from other metal ions in HEPES buffer (10 mM, pH 7.4)/CH3CN (40:60, V/V). The detection limit of WM toward Cu2+ was 1.84 × 10-7 M, which was lower than the concentration of Cu2+ in drinking water suggested by WHO and EPA. And the proposed coordination mode exhibiting the interaction between WM and Cu2+ was studied by UV-Vis, fluorescence spectrum, ESI-MS and FT-IR. Based on the fluorescent reversibility of WM, WM was considered as a molecular logic gate and molecular keypad lock. In addition, the test strips and the silica gel plates prepared from the solution of WM also demonstrate the favorable selectivity toward Cu2+.

Guanidine-modified cyclometalated iridium(III) complexes for mitochondria-targeted imaging and photodynamic therapy.

PDT is a well-established therapeutic modality for many types of cancer. Photoluminescent cyclometalated iridium(III) complexes are one of the most commonly used classes of organometallic compounds with potential beneficial applications in bioimaging and as promising anticancer agents. In the present study, three new cyclometalated iridium(III) complexes (Ir1-Ir3) containing guanidinium ligands were found to exert excellent cytotoxic effects on different types of cancer cells upon light irradiation at 425 nm. Notably, Ir1 conferred almost no dark toxicity (IC50 > 100 µM) to HepG2 cells, but the value decreased by 387-fold to 0.36 µM following 10 min of light irradiation (425 nm). Further mechanistic investigation revealed that complex Ir1 could induce apoptosis via the activation of reactive oxygen species (ROS)-mediated mitochondrial signaling pathways in the presence or absence of light irradiation. In vivo studies demonstrated that Ir1 significantly inhibited tumor growth in HepG2 xenograft-bearing mice under light irradiation at 425 nm. Taken together, these findings indicate that designing PDT-based Ir(III) complexes may hold a great deal of promise for anticancer drug development.

[Risk Analysis of Heavy Metal Contamination in Farmland Soil Around a Bauxite Residue Disposal Area in Guangxi].

Bauxite residue disposal areas (BRDA) appear to result in the heavy metal pollution of the farm fields surrounding them. In total, 194 topsoil samples were collected from the fields surrounding a BRDA in Guangxi in order to comprehensively understand the pollutant characteristics. These characteristics and their ecological risks were assessed by the Nemerow and Harkanson indices, whilst the sources and correlations of eight heavy metals (V, Cr, Ni, Cu, Zn, As, Pb, and Co) were analyzed by means of the spatial interpolation method, correlation analysis, and principal component analysis (PCA). The results demonstrated that the surrounding fields were seriously polluted by heavy metals. Ninety-two percent of samples were polluted, including 36% that showed serious pollution, and As was the dominant contaminant. The ecological risk results showed that the risks of the surrounding fields were medium, and As was responsible for 68% of this. Spatial interpolation suggested that concentrations of heavy metals in the northeastward and southwestward areas were higher, however the southeastward areas were lower. Multivariate statistics indicated that the possible source of As contaminant was different to those of V, Ni, Zn, Pb, and Co; As was primarily influenced by anthropogenic contamination, including atmospheric sedimentation, and agricultural fertilization. Cr was affected by both soil parent material and atmospheric sedimentation, whereas V, Ni, Zn, Pb, And Co levels were mainly affected by soil parent material.

A highly selective and reversible fluorescence "OFF-ON-OFF" chemosensor for Hg2+ based on rhodamine-6G dyes derivative and its application as a molecular logic gate.

A new rhodamine-6G-based chemosensor X was designed and synthesized for the colorimetric and fluorometric detection of Hg2+. The chemosensor X responsed to Hg2+ had good sensitivity, high selectivity and excellent reversibility in HEPES buffer (10 mM, pH 7.4)/CH3CN (40:60, V/V). The recognition mechanism of X toward Hg2+ was evaluated by Job's plot, IR and MS. Meanwhile, X-Hg2+ fluorescence lifetime was also measured. It was interesting that X displayed favorable reversibility to form an "off-on-off" type signaling behavior with the Hg2+-induced emission spectra being quenched by I-. Furthermore, it could be applied as a molecular logic gate and test strips based on X exhibited a good reversibility selectivity to Hg2+.

[Case-control study on therapeutic effects of different fixation methods with three Kirschners wires for the treatment of humeral supracondylar fractures].

OBJECTIVE: To compare therapeutic effects of three fixation methods with three Kirschner wires,and to find the best fixation method. METHODS: From July 2008 to May 2009, 60 patients with humeral supracondylar fractures were treated. Among patients in Group A, 11 patients were male and 9 patients were female, ranging from 2 to 13 years old,with an average of (5.4 +/- 0.5)years;all the patients in Group A were fresh closed fractures without nerve and blood vessel injuries, 13 patients were type II and 7 patients were type III according to Gartland classification; and all the patients in Group A were treated by three Kirschner wires fixation with the third Kirschner different wire fixed through radial edge of coronoid fossa. Among patients in Group B, 13 patients were male and 7 patients were female,ranging from 2 to 11 years old, with an average of (6.1 +/- 0.4) years; all the patients in Group B were fresh closed fractures without blood vessel injuries, 11 patients were type II and 9 patients were type III according to Gartland classification, 2 patients had ulnar nerve injuries before treatment; and all the patients in Group B were treated by three Kirschner wires fixation with the third Kirschner different wire fixed through ulnar edge of coronoid fossa. Among patients in Group C, 8 patients were male and 12 patients were female, ranging from 3 to 14 years old, with an average of (7.4 +/- 0.6) years; all the patients in Group C were closed fresh fractures without blood vessel injuries, 7 patients were type II and 13 patients were type III according to Gartland classification, 2 patients had radial nerve injuries before treatment; and all the patients in Group C were treated by three Kirschner wires fixation with the third Kirschner different wire fixed through middle of coronoid fossa. After 1 year of treatment,the Carrying and Baumann angles were measured on the X-ray of all patients in the three groups, and the motion range of elbow joint was observed. The Flynn evaluation criteria were used to compare therapeutic effects among the three groups. RESULTS: All the patients were followed up. The function loss of elbow joint were (14.04 +/- 3.25) degrees in Group A, (13.14 +/- 2.34) degrees in Group B, and (9.25 +/- 2.56) degrees in Group C. Changes of Carrying angle were (7.64 +/- 1.78) degrees in Group A; (7.38 +/- 1.68) degrees in Group B, and (5.27 +/- 1.13) degrees in Group C. Changes of Baumann angle were (28.55 +/- 3.23) degrees in Group A, (27.55 +/- 2.23) degrees in Group B, (21.45 +/- 1.73) degrees in Group C. According to Flynn criteria, there were 11 patients got excellent result, 4 good and 5 poor in Group A; in Group B, 12 patients got excellent result, 3 good and 5 poor; in Group C, 11 patients got excellent result, 6 good and 3 poor. The therapeutic effects of Group C was better than those of Group A and Group B. CONCLUSION: There are different effects among three kinds of operative approaches for the humerus supracondylar fractures. The fixation method with one Kirschner wire through middle part of coronoid fossa is better than the other two fixation methods.