Carbon cloth supporting spinel CuMn0.5Co2O4 nanoneedles with the regulated electronic structure by multiple metal elements as catalysts for efficient oxygen evolution reaction.

Developing transition metal oxide catalysts to replace the noble metal oxide catalysts for efficient oxygen evolution reaction (OER) is essential to promote the practical application of water splitting. Herein, we designed and constructed the carbon cloth (CC) supporting spinel CuMn0.5Co2O4 nanoneedles with regulated electronic structure by multiple metal elements with variable chemical valences in the spinel CuMn0.5Co2O4. The carbon cloth not only provided good conductivity for the catalytic reaction but also supported the well-standing spinel CuMn0.5Co2O4 nanoneedles arrays with a large special surface area. Meanwhile, the well-standing nanoneedles arrays and mesoporous structure of CuMn0.5Co2O4 nanoneedles enhanced their wettability and facilitated access for electrolyte to electrochemical catalysis. Besides, the regulated electronic structure and generated oxygen vacancies of CuMn0.5Co2O4/CC by multiple metal elements improved the intrinsic catalytic activity and the durability of OER activity. Profiting from these merits, the CuMn0.5Co2O4/CC electrode exhibited superior OER activity with an ultralow overpotential of 189 mV at the current density of 10 mA⋅cm-2 and a smaller Tafel slope of 64.1 mV⋅dec-1, which was competitive with the noble metal oxides electrode. And the CuMn0.5Co2O4/CC electrode also exhibited long-term durability for OER with 95.3% of current retention after 1000 cycles. Therefore, the competitive OER activity and excellent cycling durability suggested that the CuMn0.5Co2O4/CC electrode is a potential candidate catalyst for efficient OER.

Microbial gradual shifts during the process of species replacement in Taihang Mountain.

Introduction: Understanding microbial gradual shifts along species replacement can help elucidate the mechanisms driving secondary succession, and predict microbial responses to changing environments. However, how climate-induced species replacement alters microbial processes, and whether microbial shifts follow predictable assembly trajectories remain unclear. Methods: Using space-for-time substitution approach, we studied shifts in bacterial and fungal communities in the succession from Leptodermis oblonga to Vitex negundo var. heterophylla shrubland in Taihang Mountain. Results and Discussion: Species replacement, induced by climate related environmental change, significantly increased the above-ground biomass of shrublands, and TP and TK contents in topsoil. The succession from L. oblonga to V. negundo var. heterophylla communities resulted in the gradually replacement of cold-tolerant microbes with warm-affinity ones, and alterations of microbial communities involved in soil biogeochemical processes. Soil and plant variables, such as above-ground biomass, soil pH, total phosphorus, and total potassium, well explained the variations in microbial communities, indicating that the coordinated changes in plant communities and soil properties during secondary succession caused accompanied shifts in microbial diversity and composition.

Application of microalgae Chlamydomonas applanata M9V and Chlorella vulgaris S3 for wheat growth promotion and as urea alternatives.

Excessive use of chemical fertilizers to meet the global food demand has caused extensive environmental pollution. Microalgae can be used to enhance agricultural crop production as a potentially sustainable and eco-friendly alternative. In this study, Chlamydomonas applanata M9V and Chlorella vulgaris S3 were isolated from the soil and mass-cultured for use as microalgal fertilizers. The influence of microalgae M9V and S3 on the growth of wheat (Triticum aestivum L.) and soil properties was evaluated and compared with that of chemical urea fertilizer. A pot experiment was conducted with six treatments, i.e., living M9V (M9VL), dead M9V (M9VD), living S3 (S3L), dead S3 (S3D), urea fertilizer (urea), and control without fertilizer (control). M9VL was found to have the best effect on wheat growth promotion, followed by M9VD and S3D. In addition, M9VL resulted in the highest enhancement of shoot fresh weight (166.67 and 125.68%), root dry weight (188.89 and 77.35%), leaf length (26.88 and 14.56%), root length (46.04 and 43.93%), chlorophyll a (257.81 and 82.23%), and chlorophyll b contents (269.00 and 247.27%) comparing to the control and urea treatments, respectively. Moreover, all microalgal fertilizer treatments increased soil organic matter (SOM) by 1.77-23.10%, total carbon (TC) by 7.14-14.46%, and C:N ratio by 2.99-11.73% compared to the control and urea treatments. Overall, this study provided two microalgae strains, M9V and S3, that could promote wheat growth and improve soil properties, thus highlighting the use of microalgae as biofertilizers to reduce the use of chemical fertilizers and promoting sustainable agricultural production.

Multifunctional effects of hollow flower-like CoTiO3 microspheres wrapped by reduced graphene as sulfur host in Li-S battery.

The poor conductivity of sulfur, the shuttle effect and sluggish redox reaction kinetics of lithium polysulfides (LiPSs) are considered the main obstacles to the practical application of Lithium-sulfur (Li-S) batteries. Thus, it is urgent to design multifunctional host materials to eliminate these obstacles. Herein, we designed a hollow flower-like CoTiO3 wrapped by reduced graphene oxide (h-CoTiO3@rGO) as sulfur host materials. The hollow structure of h-CoTiO3@rGO not only endows sufficient space for high sulfur loading, but also physically and chemically confines the shuttle effect of LiPSs through the formation of Co-S chemical bonding. The large specific surface area and excellent electrocatalytic ability of h-CoTiO3@rGO provide amounts of active sites to accelerate the redox reaction of LiPSs. Meanwhile, the conductive reduced graphene oxide (rGO) covered on the surface of CoTiO3 microspheres offers an interconnected conductive network to support the fast electron/ion transfer. Profit from these merits, the battery employing the multifunctional h-CoTiO3@rGO as sulfur host exhibited excellent cycling stability with an ultralow capacity fading of 0.0127 % per cycle after 500 cycles at 1C. Even the battery with high sulfur loading of 5.2 mg/cm2 still delivered a high area capacity of 5.02 mAh/cm2, which was competitive with the commercial Li-ion batteries. Therefore, the competitive capacity and superior cycling stability suggest that the h-CoTiO3@rGO/S cathode is a potential candidate for high-performance Li-S batteries.

Trichoderma Enhances Net Photosynthesis, Water Use Efficiency, and Growth of Wheat (Triticum aestivum L.) under Salt Stress.

Soil salinity is one of the most important abiotic stresses limiting plant growth and productivity. The breeding of salt-tolerant wheat cultivars has substantially relieved the adverse effects of salt stress. Complementing these cultivars with growth-promoting microbes has the potential to stimulate and further enhance their salt tolerance. In this study, two fungal isolates, Th4 and Th6, and one bacterial isolate, C7, were isolated. The phylogenetic analyses suggested that these isolates were closely related to Trichoderma yunnanense, Trichoderma afroharzianum, and Bacillus licheniformis, respectively. These isolates produced indole-3-acetic acid (IAA) under salt stress (200 mM). The abilities of these isolates to enhance salt tolerance were investigated by seed coatings on salt-sensitive and salt-tolerant wheat cultivars. Salt stress (S), cultivar (C), and microbial treatment (M) significantly affected water use efficiency. The interaction effect of M x S significantly correlated with all photosynthetic parameters investigated. Treatments with Trichoderma isolates enhanced net photosynthesis, water use efficiency and biomass production. Principal component analysis revealed that the influences of microbial isolates on the photosynthetic parameters of the different wheat cultivars differed substantially. This study illustrated that Trichoderma isolates enhance the growth of wheat under salt stress and demonstrated the potential of using these isolates as plant biostimulants.

Porous ZnO Ultrathin Nanosheets with High Specific Surface Areas and Abundant Oxygen Vacancies for Acetylacetone Gas Sensing.

In this study, porous ZnO ultrathin nanosheets with abundant surface oxygen vacancies were prepared by a hydrothermal technique followed by an annealing method using graphene oxide (GO) as a template. The high specific surface area of GO with ultrathin thickness provided an important template for the ZnO ultrathin nanosheets. The as-prepared porous ZnO ultrathin nanosheets exhibited superior acetylacetone sensing performance. The sensor response of the porous ZnO ultrathin nanosheets was 191.1 for 100 ppm acetylacetone, which was approximately 4 times higher than that of ZnO clusters (prepared without GO template) at 340 °C. The porous ZnO ultrathin nanosheets also exhibited excellent selectivity and operational stability. The excellent gas sensing performance of the porous ZnO ultrathin nanosheets was due to their high specific surface area (130.5 m2/g) and abundant surface oxygen vacancy.

Synthesis and coloration of highly dispersive SiO2/BiVO4 hybrid pigments with low cost and high NIR reflectance.

Highly dispersed SiO2/BiVO4 hybrid pigments with a spherical structure and high near-infrared (NIR) reflectance have been successfully fabricated by a facile sol-gel method followed by calcination. The dispersed and uniformly spherical particles of the hybrid pigments were caused by the support provided by SiO2 microspheres, and their color was adjusted via the band-gap energy, which was changed with the incorporation of SiO2 microspheres. The SiO2/BiVO4-3 hybrid pigment presented higher yellow hues (b* = 91.42) and more dispersed spherical particles than other as-prepared hybrid pigments and commercially available BiVO4-based yellow pigment. This strategy could save 72 wt% resource of BiVO4 while yielding the same amount of yellow pigment with high color performance. Therefore, the prepared hybrid pigments not only dramatically decreased the cost of expensive pigments, but also saved scarce resources and reduced environmental pollution. In addition, the SiO2/BiVO4-3 hybrid pigment also presented high NIR reflective performance, which demonstrated that it would be a favorable candidate for colorful NIR reflective pigments with wide applications in heat insulation.

Photocatalytic H2 Evolution on TiO2 Assembled with Ti3C2 MXene and Metallic 1T-WS2 as Co-catalysts.

The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst's surface. In this paper, we report that double metallic co-catalysts Ti3C2 MXene and metallic octahedral (1T) phase tungsten disulfide (WS2) act pathways transferring photoexcited electrons in assisting the photocatalytic H2 evolution. TiO2 nanosheets were in situ grown on highly conductive Ti3C2 MXenes and 1T-WS2 nanoparticles were then uniformly distributed on TiO2@Ti3C2 composite. Thus, a distinctive 1T-WS2@TiO2@Ti3C2 composite with double metallic co-catalysts was achieved, and the content of 1T phase reaches 73%. The photocatalytic H2 evolution performance of 1T-WS2@TiO2@Ti3C2 composite with an optimized 15 wt% WS2 ratio is nearly 50 times higher than that of TiO2 nanosheets because of conductive Ti3C2 MXene and 1T-WS2 resulting in the increase of electron transfer efficiency. Besides, the 1T-WS2 on the surface of TiO2@Ti3C2 composite enhances the Brunauer-Emmett-Teller surface area and boosts the density of active site.

Molecular Evidence for Catechin Synthesis and Accumulation in Tea Buds (Camellia sinensis).

Early spring buds of the Camellia sinensis variety Shuchazao were separated into two parts, including the shoot tip (ST) and non-expanded young leaves (YL), in which the synthesis and accumulation of catechins in the two parts were assessed by high-performance liquid chromatography (HPLC), p-dimethylaminocinnamaldehyde (DMACA) staining, quantitative real-time polymerase chain reaction (qRT-PCR), and in situ hybridization. HPLC showed that (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) amounts in YL were increased significantly by 74.0 and 71.8%, respectively. The results of DMACA staining indicated that catechins in buds accumulated mainly in mesophyll cells and the bud shaft of YL. Meanwhile, qRT-PCR demonstrated that the relative expression levels of genes related to flavonoid metabolism, including CsPAL1, CsC4H1, CsC4H2, CsCHS2, CsF3'5'H1, CsDFR1, CsDFR2, and CsANR1, were significantly higher in YL than in the ST. In situ hybridization revealed that CsDFR1, CsDFR2, CsLAR, and CsANR1 were expressed in leaf primordia and YL but not in the apical meristem. These findings highlight the synthesis and accumulation patterns of catechins in different parts of the ST in C. sinensis, providing a theoretical basis for the assessment of synthesis, accumulation, and transfer patterns of catechins in tea plants.

Hierarchical assembly of In2O3 nanoparticles on ZnO hollow nanotubes using carbon fibers as templates: Enhanced photocatalytic and gas-sensing properties.

A novel hollow hierarchical nano-heterostructure consisting of ZnO nanorods coated with In2O3 nanoparticles was prepared using a hydrothermal method combined with an annealing treatment via carbon fiber (CF) templates. Experimental results reveal that the In2O3/ZnO hierarchical composite has a tubular structure with an average diameter of ∼6µm and In2O3 nanoparticles distribute uniformly on the ZnO nanorods. Significantly, the obtained heterostructure shows enhanced visible light photoactivity to methyl orange (MO) degradation and good selectivity and response toward ethanol even at a low detection limit (1ppm). This outstanding performance is a result of the one-dimensional tubular structure and the heterostructure formation between In2O3 and ZnO, advantageous for the adsorption and diffusion and the separation of electrons and holes. In addition, the excellent performance is greatly improved by virtue of the evenly decorated In2O3 nanoparticles on the ZnO nanorod surfaces, which provide more active sites for pollutants and gases.

Visible photocatalytic and photoelectrochemical activities of TiO2 nanobelts modified by In2O3 nanoparticles.

Novel In2O3 nanoparticle/TiO2 nanobelt heterostructures with enhanced visible-light photocatalytic and photoelectrochemical (PEC) performance were successfully prepared via a facile hydrothermal method. Well-dispersed In2O3 nanoparticles with small sizes are uniformly attached on the surface of TiO2 nanobelts to form In2O3 nanoparticle/TiO2 nanobelt heterostructures. The TiO2 nanobelts as backbones restrict the aggregation of In2O3 nanoparticles, resulting in the formation of smaller In2O3 nanoparticles with more interaction sites for pollutants. The visible photocatalytic activity of as-prepared heterostructures for degradation of methyl blue (MB) is higher than those of TiO2 nanobelts and In2O3 nanoparticles alone. Moreover, the In2O3 nanoparticle/TiO2 nanobelt heterostructure shows an enhanced PEC performance under irradiation of visible light. The enhanced photocatalytic and PEC activities are mainly ascribed to the synergic effect of efficient charge separation of heterostructure, visible-light harvesting ability of In2O3, and the formation of preferential adsorption sites by the small size of In2O3 nanoparticles. Finally, based on the experimental results of Mott-Schottky, UV-vis DRS, photocurrent and open-circuit voltage response, a possible photocatalytic mechanism over the In2O3 nanoparticle/TiO2 nanobelt heterostructure is proposed.

Novel groups and unique distribution of phage phoH genes in paddy waters in northeast China.

Although bacteriophages are ubiquitous in various environments, their genetic diversity is primarily investigated in pelagic marine environments. Corresponding studies in terrestrial environments are few. In this study, we conducted the first survey of phage diversity in the paddy ecosystem by targeting a new viral biomarker gene, phoH. A total of 424 phoH sequences were obtained from four paddy waters generated from a pot experiment with different soils collected from open paddy fields in northeast China. The majority of phoH sequences in paddy waters were novel, with the highest identity of ≤70% with known phoH sequences. Four unique groups (Group α, Group ß, Group γ and Group δ) and seven new subgroups (Group 2b, Group 3d, Group 3e, Group 6a, Group 6b, Group 6c and Group 6d) were formed exclusively with the clones from the paddy waters, suggesting novel phage phoH groups exist in the paddy ecosystem. Additionally, the distribution proportions of phoH clones in different groups varied among paddy water samples, suggesting the phage community in paddy fields is biogeographically distributed. Furthermore, non-metric multidimensional scaling analysis indicated that phage phoH assemblages in paddy waters were distinct from those in marine waters.

Novel groups of cyanobacterial podovirus DNA polymerase (pol) genes exist in paddy waters in northeast China.

In this study, we surveyed cyanopodovirus DNA polymerase (pol) sequences in paddy waters using the culture-independent PCR and Sanger sequencing methods. Four paddy waters generated from a pot experiment with different soil types collected from op E: n paddy fields in northeast China were used in this study. A total of 438 DNA pol clones were identified as cyanopodoviruses. The clones from the paddy waters formed nine unique groups of cyanopodoviruses either exclusively or with clones from East Lake in China (subclusters α-1 to α-8 and cluster ß). None of the clones from open oceans or coastal waters fell into these unique groups. Additionally, the distribution proportions of the clones into different cyanopodovirus groups varied among paddy water samples, which suggested that the cyanopodovirus compositions were spatially distributed in the paddy fields. The comparison of clone libraries in different studies indicated that the diversity of cyanopodoviruses in paddy waters was comparable to the diversity in the open oceans but was less than the diversity in the coastal estuary of Chesapeake Bay. Non-metric multidimensional scaling analysis indicated that the cyanopodovirus communities in paddy waters were similar to those in lake freshwater but distinct from the communities in marine and coastal waters.

Functional analysis of flavonoid 3',5'-hydroxylase from tea plant (Camellia sinensis): critical role in the accumulation of catechins.

BACKGROUND: Flavonoid 3',5'-hydroxylase (F3'5'H), an important branch point enzyme in tea plant flavan-3-ol synthesis, belongs to the CYP75A subfamily and catalyzes the conversion of flavones, flavanones, dihydroflavonols and flavonols into 3',4',5'-hydroxylated derivatives. However, whether B-ring hydroxylation occurs at the level of flavanones and/or dihydroflavonols, in vivo remains unknown. RESULTS: The Camellia sinensis F3'5'H (CsF3'5'H) gene was isolated from tea cDNA library. Expression pattern analysis revealed that CsF3'5'H expression was tissue specific, very high in the buds and extremely low in the roots. CsF3'5'H expression was enhanced by light and sucrose. Over-expression of CsF3'5'H produced new-delphinidin derivatives, and increased the cyanidin derivative content of corollas of transgenic tobacco plants, resulting in the deeper transgenic plant flower color. Heterologous expressions of CsF3'5'H in yeast were carried out to demonstrate the function of CsF3'5'H enzyme in vitro. Heterologous expression of the modified CsF3'5'H (CsF3'5'H gene fused with Vitis vinifera signal peptide, FSI) revealed that 4'-hydroxylated flavanone (naringenin, N) is the optimum substrate for CsF3'5'H, and was efficiently converted into both 3'4'- and 3'4'5'-forms. The ratio of 3'4'5'- to 3'4'-hydroxylated products in FSI transgenic cells was significantly higher than VvF3'5'H cells. CONCLUSIONS: CsF3'5'H is a key controller of tri-hydroxyl flavan-3-ol synthesis in tea plants, which can effectively convert 4'-hydroxylated flavanone into 3'4'5'- and/or 3'4'-hydroxylated products. These findings provide animportant basis for further studies of flavonoid biosynthesis in tea plants. Such studies would help accelerate flavonoid metabolic engineering in order to increase B-ring tri-hydroxyl product yields.

Synthesis of nestlike ZnO hierarchically porous structures and analysis of their gas sensing properties.

Nestlike 3D ZnO porous structures with size of 1.0-3.0 µm have been synthesized through annealing the zinc hydroxide carbonate precursor, which was obtained by a one-pot hydrothermal process with the assistance of glycine, Na(2)SO(4), and polyvinyl pyrrolidone (PVP). The nestlike 3D ZnO structures are built of 2D nanoflakes with the thickness of ca. 20 nm, which exhibit the nanoporous wormhole-like characteristic. The measured surface area is 36.4 m(2)g(-1) and the pore size is ca. 3-40 nm. The unique nestlike 3D ZnO porous structures provided large contacting surface area for electrons, oxygen and target gas molecules, and abundant channels for gas diffusion and mass transport. Gas sensing tests showed that the nestlike 3D ZnO porous structures exhibit excellent gas sensing performances such as high sensitivity and fast response and recovery speed, suggesting the potential applications as advanced gas sensing materials.

Regulatory T cells are associated with post-cryoablation prognosis in patients with hepatitis B virus-related hepatocellular carcinoma.

BACKGROUND: We carried out this study to evaluate the association between regulatory T cells (Treg) and prognosis and progression after cryoablation in patients with hepatitis-B virus-related hepatocellular carcinoma. METHODS: Peripheral Treg frequency in 111 patients with hepatocellular carcinoma (HCC) was detected by flow cytometry. Treg frequency and function were re-examined during patient follow up. A possible association between Treg and α-fetoprotein (AFP) was also analyzed, and the distribution of resident CD4(+) and CD8(+) T cells and FoxP3(+) T cells in the liver tissue of patients with HCC was examined by immunohistochemistry. RESULTS: Treg frequency significantly increased with disease progression. Our longitudinal study showed that Treg frequency had significantly decreased in 17 patients with HCC regression following cryoablation, but the frequency had dramatically increased in 14 patients with HCC recurrence or progression. Furthermore, AFP levels varied in a way comparable with Treg frequency in patients with elevated AFP recorded before therapy. Significantly increased suppressive effects of Treg on proliferation and cytokine secretion of CD8(+) and CD4(+) T cells were observed during follow up in patients with tumor progression, but not in patients with tumor response. Moreover, the numbers of CD8(+), CD4(+), and FoxP3(+) cells infiltrating the tumors around the cryotherapeutic zones were significantly decreased after argon-helium cryoablation, and this was associated with a reduction in the FoxP3/CD8 ratio. Importantly,increased quantities of circulating CD4(+)CD25(+)FoxP3(+) Treg and tumor infiltrating FoxP3(+) cells before cryoablation were associated with high recurrence or risk of progression in HCC patients after cryoablation. CONCLUSIONS: Treg variation is associated with tumor regression or progression in HCC following cryoablation and may be used as a marker to estimate HCC progression.

Prognostic factors and recurrence of hepatitis B-related hepatocellular carcinoma after argon-helium cryoablation: a prospective study.

To determine the long-term prognosis of hepatocellular carcinoma (HCC) after argon-helium cryoablation and identify the risk factors that predict metastasis and recurrence. A total of 156 patients with hepatitis B-related HCC less than 5 cm in diameter who underwent curative cryoablation were followed up prospectively for tumor metastasis and recurrence. Immunohistochemistry was used to analyze the expression of vascular endothelial growth factor (VEGF). HBV basal core promoter (BCP) and precore mutations were detected by DNA sequence analysis. Post-treatment prognostic factors influencing survival, tumor metastasis and recurrence were assessed by univariate and multivariate analyses. The variables included the expression of VEGF in HCC tissues, clinical and pathologic characteristics of patients, and HBV features (HBV DNA level, HBV genotype, BCP mutation). The median follow-up period of the 156 patients was 37 months (range 8-48 months). The 1-, 2-, and 3-year overall survival rates were 92, 82 and 64%, respectively. The 1-, 2-, and 3-year recurrence-free survival rates were 72, 56 and 43%, respectively. Eighty-five patients (54.5%) had tumor recurrence or metastasis. The multivariate analysis showed that Child-Pugh class and the expression of VEGF in HCC tissues could be used as independent prognostic factors for overall survival. Meanwhile, the expression of VEGF in HCC tissues and HBV BCP mutations were found to be independent prognostic factors for recurrence-free survival. Strong expression of VEGF in HCC tissues and HBV BCP mutations are important risk predictors for recurrence or metastasis of HCC smaller than 5 cm in diameter.

Efficacy of argon-helium cryosurgical ablation on primary hepatocellular carcinoma: a pilot clinical study.

BACKGROUND AND OBJECTIVE: Recent years, great progression has been made in treating primary hepatocellular carcinoma (HCC) with argon-helium cryosurgical ablation. This study was to evaluate its efficacy on unresectable primary HCC. METHODS: A total of 124 primary HCC patients were divided into early stage, middle stage and advanced stage groups according to BCLC staging classification. Clinical symptoms, tumor size, serum level of alpha-fetoprotein (AFP), complications, and survival time were analyzed. RESULTS: After cryoablation of the tumors, serum level of AFP was reduced in 76 (82.6%) patients, 205 (92.3%) of the 222 tumor lesions were diminished or unchanged. Untill April 2008, 14 patients survived and 110 died. The median survival time was 31.25 months in early stage group, 17.41 months in middle stage group and 6.82 months in advanced stage group. CONCLUSION: For the patients with unresectable HCC, argon-helium cryosurgical ablation has the advantages of few complications and certain efficacy.