Smartphone-assisted nanozyme sensor array constructed based on reaction kinetics for the discrimination and identification of phenolic compounds.

Although the research on nanozymes has attracted widespread attention in recent years, the development of highly active and multifunctional nanozymes remains a challenge. Here, a bifunctional AMP-Cu nanozyme with laccase- and catecholase-like activities was successfully prepared at room temperature with Cu2+ as the metal ion and adenosine-5'-monophosphate (AMP) as the ligand molecule. Based on the excellent catalytic performance of AMP-Cu, a three-channel colorimetric sensor array was constructed using reaction kinetics as the sensing unit to achieve high-throughput detection and identification of six common phenolic compounds at low concentrations. This strategy simplifies the construction of sensor array and demonstrates the capacity to obtain multidimensional data from a single material. Finally, with the assistance of smartphones and homemade dark boxes, a portable on-site detection method for phenolic compounds was developed. This work would contribute to the development of portable sensors and the highly efficient identification of phenolic compounds in complex samples.

Developing efficient vanillin biosynthesis system by regulating feruloyl-CoA synthetase and enoyl-CoA hydratase enzymes.

Vanillin is one of the most commonly used natural-occurring flavors in the world. This study successfully constructed an efficient whole-cell catalytic system for vanillin biosynthesis from ferulic acid by regulating feruloyl-CoA synthetase (FCS) and enoyl-CoA hydratase (ECH). First, we constructed an efficient cell-free catalytic system with FCS-Str (fcs from Streptomyces sp. V-1) and ECH-Str (ech from Streptomyces sp. V-1) combination at 1:1. The efficient cell-free catalytic system provided necessary strategies for optimizing the whole-cell catalytic system. Then, we constructed the recombinant Escherichia coli by heterologously expressing the fcs-Str and ech-Str combination. Moreover, E. coli JM109 was a better recombinant Escherichia coli than E. coli BL21 with higher vanillin production. Finally, we first adjusted the ratio of FCS and ECH in E. coli JM109 to 1:1 using two copies of fcs-Str. For higher vanillin production, we further optimized the induction conditions of E. coli JM109 to increase the amount of FCS and ECH. The optimized E. coli JM109-FE-F constructed in this study has the highest vanillin synthesis rate of converting 20 mM ferulic acid to 15 mM vanillin in 6 h among all of the E. coli catalytic systems. Our study made a significant contribution to the construction of the vanillin biosynthesis system and provided a valuable strategy for increasing vanillin production. KEY POINTS: • The efficient cell-free vanillin biosynthesis system was constructed by FCS-Str and ECH-Str combination at 1:1. • Escherichia coli JM109 was determined as a better recombinant Escherichia coli than E. coli BL21 with higher vanillin production. • Escherichia coli JM109-FE-F with two copies of fcs-Str and one copy of ech-Str has the highest catalytic efficiency for vanillin production.

Heterostructure engineering of ultrathin SnS2/Ti3C2Tx nanosheets for high-performance potassium-ion batteries.

Layered metal sulfides are considered as promising candidates for potassium ion batteries (KIBs) owing to the unique interlayer passages for ion diffusion. However, the insufficient electronic conductivity, inevitable volume expansion, and sulfur loss hinder the promotion of K-ion storage performance. Herein, few-layered Ti3C2Tx nanosheets were selected as the multi-functional substrate for cooperating few-layered SnS2 nanosheets, constructing SnS2/Ti3C2Tx hetero-structural nanosheets (HNs) with the thickness as thin as about 5 nm. In this configuration, the formed Ti-S bonds provide robust interaction between SnS2 and Ti3C2Tx nanosheets, which hinders the agglomeration of SnS2 and the restack of Ti3C2Tx, endowing the hybrid material with robust nanostructure. Thus, the shortcomings of the SnS2 anode are muchly relieved. In this way, the as-prepared SnS2/Ti3C2Tx HNs electrode delivers reversible capacities of 462.1 mAh g-1 at 0.1 A g-1 and 166.1 mAh g-1 at 2.0 A g-1, respectively, and a capacity of 85.5 mAh g-1 is remained even after 460 cycles at 2.0 A g-1. These results are superior to those of the counterpart electrode, confirming aggressive promotion of K-ion storage performance of SnS2 anode brought by the cooperation of Ti3C2Tx, and presenting a reliable strategy to improve the electrochemical performance of sulfide anodes.

Self-induced matrix with Li-ion storage activity in ultrathin CuMnO2 nanosheets electrode.

Conversion anode materials such as Mn3O4 draw much attention due to their considerable theoretical capacity for lithium-ion batteries (LIBs). However, poor conductivity, slow solid-state Li-ion diffusion, and huge volume expansion of the active materials during charge/discharge lead to unsatisfied electrochemical performance. Despite several strategies like nanocrystallization, fabricating hierarchical nanostructures, and introducing a matrix are valid to address these crucial issues, the achieved electrochemical performance still needs to be further enhanced. What is worse, the matrix with less or no Li-ion storage activity may lower the achieved capacity of the electrodes. Herein, ultra-thin CuMnO2 nanosheets with the thickness of 5-8 nm were evaluated for LIBs. The ultra-thin sheet-like nanostructure offers sufficient contact areas with electrolyte and shortens the Li-ion diffusion distance. Moreover, the in-situ generated Mn and Cu along with their oxides could play the role of matrix and conductive agent in turn at different stages, relieving the stress brought by volume expansion. Therefore, the as-prepared ultra-thin CuMnO2 nanosheets electrode displays a remarkable reversible capacity, long cycling stability, and outstanding rate capability (a reversible capacity of 1160.5 mAh g-1 at 0.1A g-1 was retained after 100 cycles with a capacity retention of 95.1 %, and 717.8 mAh g-1 at 2.0 A g-1 after 400 cycles).

Enhanced ß-carotene production by overexpressing the DID2 gene, a subunit of ESCRT complex, in engineered Yarrowia lipolytica.

OBJECTIVE: ß-Carotene has been widely used in the food and feed industry and has significant commercial value. This study aimed to increase the ß-carotene production in engineered Yarrowia lipolytica by optimizing the host metabolic network. The DID2 gene, a subunit of the endosomal sorting complex required for transport (ESCRT), was integrated into a ß-carotene producing strain. RESULTS: The ß-carotene production was increased by 260%, and the biomass increased by 10% for engineered Y. lipolytica. Meanwhile, DID2 elevated the mRNA level and protein level of the genes in the ß-carotene synthesis pathway, then increased precursors (FPP, Lycopene) utilization. DID2 also increased the mRNA level of the genes in the glucose pathway, pentose phosphate pathway, and tricarboxylic acid cycle and promoted glucose utilization and cofactors consumption. CONCLUSION: The ESCRT protein complex subunit, DID2, improved ß-carotene production in engineered Y. lipolytica and beneficial to glucose utilization and cofactors consumption. This study provided new finding of the DID2 gene's function and it mostly could be used for many other natural product productions.

Stimulating the Reversibility of Sb2 S3 Anode for High-Performance Potassium-Ion Batteries.

Conversion-alloy sulfide materials for potassium-ion batteries (KIBs) have attracted considerable attention because of their high capacities and suitable working potentials. However, the sluggish kinetics and sulfur loss result in their rapid capacity degeneration as well as inferior rate capability. Herein, a strategy that uses the confinement and catalyzed effect of Nb2 O5 layers to restrict the sulfur species and facilitate them to form sulfides reversibly is proposed. Taking Sb2 S3 anode as an example, Sb2 S3 and Nb2 O5 are dispersed in the core and shell layers of carbon nanofibers (C NFs), respectively, constructing core@shell structure Sb2 S3 -C@Nb2 O5 -C NFs. Benefiting from the bi-functional Nb2 O5 layers, the electrochemical reversibility of Sb2 S3 is stimulated. As a result, the Sb2 S3 -C@Nb2 O5 -C NFs electrode delivers the rapidest K-ion diffusion coefficient, longest cycling stability, and most excellent rate capability among the controlled electrodes (347.5 mAh g-1 is kept at 0.1 A g-1 after 100 cycles, and a negligible capacity degradation (0.03% per cycle) at 2.0 A g-1 for 2200 cycles is delivered). The enhanced K-ion storage properties are also found in SnS2 -C@Nb2 O5 -C NFs electrode. Encouraged by the stimulated reversibility of Sb2 S3 and SnS2 anodes, other sulfides with high electrochemical performance also could be developed for KIBs.

Dissolved-oxygen feedback control fermentation for enhancing ß-carotene in engineered Yarrowia lipolytica.

The DO-stat fed-batch fermentation was carried out to explore the volumetric productivity of ß-carotene in engineered Yarrowia lipolytica C11 strain. Using DO-stat fed-batch fermentation, we achieved 94 g/L biomass and 2.01 g/L ß-carotene. Both biomass and ß-carotene were about 1.28-fold higher than that in fed-batch fermentation. The ATP, NADP+/NADPH, and gene expression levels of tHMG, GGS1, carRA, and carB were promoted as compared to that in fed-batch fermentation. As for as the kinetic parameters in DO-stat fed-batch fermentation, µm', Yx/s', and Yp/s' was 0.527, 0.353, and 0.158, respectively. The µm' was elevated 4.66-fold than that in fed-batch fermentation. These data illustrate that more dissolved oxygen increased the biomass. The Yx/s' and Yp/s' were increased 1.15 and 22.57-fold, which suggest that the DO-stat fed-batch fermentation reduced the Crabtree effect and improved the utilization rate of glucose. Therefore, DO-stat fed-batch fermentation is a promising strategy in the industrialized production of ß-carotene.

Promoting the Synthesis of Precursor Substances by Overexpressing Hexokinase (Hxk) and Hydroxymethylglutaryl-CoA Synthase (Erg13) to Elevate ß-Carotene Production in Engineered Yarrowia lipolytica.

As a valuable carotenoid, ß-carotene is commercially used in food, cosmetics, animal feeds, and other industries. Metabolic engineering of microorganisms has been widely explored to improve the production of ß-carotene. Compared with the traditional genetic modifications mainly focused on the pathways of mevalonate (MVA) and ß-carotene biosynthesis, this study aims to increase the ß-carotene production through promoting the synthesis of precursor substances by overexpressing hexokinase and hydroxymethylglutaryl-CoA synthase in an engineered Yarrowia lipolytica. In this study, we investigated the effect of the unique hexokinase gene (Hxk) overexpression on ß-carotene accumulation and glucose consumption. The Hxk gene was introduced into a ß-carotene producing strain Y.L-1 to generate strain Y.L-2, and this increased the ß-carotene content by 98%. Overexpression of the Hxk gene led to increasing in hexokinase activity (329% higher), glucose-6-phosphate content (92% higher), and improvement of the transcriptional level of Hxk (315% higher) compared to the control Y.L-1 strain. Moreover, Hxk overexpression accelerated the utilization rate of glucose. The gene erg13 encoding hydroxymethylglutaryl-CoA synthase was also overexpressed to increase the precursor supply for ß-carotene biosynthesis. Recombinant Y.L-4 harboring two copies of erg13 produced 8.41 mg/g dry cell weight (DCW) of ß-carotene, which was 259% higher than Y.L-1. The ß-carotene content of 9.56 mg/g DCW was achieved in strain Y.L-6 by integrating erg13 into the chromosome and Hxk overexpression. The 3-Hydroxy-3-Methylglutaryl-CoA content in the cells was increased by overexpressing two copies of the erg13 gene. Finally, the titer of ß-carotene reached 2.4 g/L using a 50 L bioreactor by the engineered strain, and the fermentation cycle was shortened from 144 to 120 h. Overall, overexpression of Hxk and erg13 could improve ß-carotene production and successfully overcoming the bottleneck of precursor generation to support a more efficient pathway for the production of the target product. Our results revealed a novel strategy to engineer the pathway of ß-carotene synthesis.

Overexpression of △12, △15-Desaturases for Enhanced Lipids Synthesis in Yarrowia lipolytica.

Microbial oil triacylglycerol (TAG) from the renewable feedstock attract much attention. The oleaginous yeast Yarrowia lipolytica has become the most studied for lipid biosynthesis. Fatty acid desaturases catalyze the introduction of a double bond into fatty-acid hydrocarbon chains to produce unsaturated fatty acids. Desaturases are known to enhance lipid accumulation. In this study, we have achieved a significant increase in lipid production and increase the unsaturated fatty acids content in Y. lipolytica. By comparing the expression of the native genes of △-9 stearoyl-CoA desaturase (SCD) and △12 desaturase (△12D), and an exogenous △15 desaturase (△15D) from flax in the strain with deleted peroxisomal biogenesis factor 10 (PEX10) and overexpressed diacylglyceride acyl-transferase (DGA1), we found that the strain with overexpressed △15 desaturase accumulated 30.7% lipid. Simultaneously, we explored the effect of two copies of desaturase genes (12D-SCD, 15D-SCD, 12D-15D) on lipid production, and found co-expression of △12D and △15D accumulated 42.6% lipid. The lipid content was further increased by 56.3% through the deletion of the multifunctional enzyme (MFE1) and the overexpression of acetyl-CoA carboxylase (ACC1). Finally, the lipid productivity of 50 g/L and maximal lipid content of 77.8% DCW are obtained using a 5-L stirred-tank bioreactor during the stationary phase in the engineered YL-10. Our result demonstrated that the △12 and △15 desaturases play an important role in lipid production in Y. lipolytica and provides an effective strategy for biodiesel development.

Elevated ß-Carotene Synthesis by the Engineered Rhodobacter sphaeroides with Enhanced CrtY Expression.

ß-Carotene is a precursor of vitamin A and a dietary supplement for its antioxidant property. Producing ß-carotene by microbial fermentation has attracted much attention owing to consumers' preference for the natural product. In this study, an engineered photosynthetic Rhodobacter sphaeroides producing ß-carotene was constructed by the following strategies: (1) five promoters of different strengths were used to investigate the effect of the expression level of crtY on ß-carotene content. It was found that PrrnB increased the ß-carotene content by 109%. (2) blocking of the branched pentose phosphate pathway by zwf deletion, and (3) overexpressing dxs could restore the transcriptional levels of crtE and crtB. Finally, the engineered RS-C3 has the highest ß-carotene content of 14.93 mg/g dry cell weight (DCW) among all of the reported photosynthetic bacteria and the ß-carotene content reached 3.34 mg/g DCW under light conditions. Our results will be available for industrial use to supply a large quantity of natural ß-carotene.

Engineering the Core-Shell-Structured NCNTs-Ni2Si@Porous Si Composite with Robust Ni-Si Interfacial Bonding for High-Performance Li-Ion Batteries.

A new strategy has been innovatively proposed for wrapping the Ni-incorporated and N-doped carbon nanotube arrays (Ni-NCNTs) on porous Si with robust Ni-Si interfacial bonding to form the core-shell-structured NCNTs-Ni2Si@Si. The hierarchical porous silicon core was first fabricated via a novel self-templating synthesis route based on two crucial strategies: in situ thermal evaporation of crystal water from the perlite for producing porous SiO2 and subsequent magnesiothermic reduction of porous SiO2 into porous Si. Ni-NCNTs were subsequently constructed based on the Ni-catalyzed tip-growth mechanism and were further engineered to fully wrap the porous Si microparticles by forming the Ni2Si alloy at the heterojunction interface. When the prepared NCNTs-Ni2Si@Si was evaluated as the anode material for Li-ion batteries, the hierarchical porous system in the Si core and the rich void spaces in carbon nanotube arrays contributed to the remarkable accommodation of volume expansion of Si as well as the significant increase of Li+ diffusion and Si utilization. Moreover, the Ni2Si alloy, which chemically linked the Ni-NCNTs and porous Si, not only provided good electronic contact between the Si core and carbon shell but also effectively prevented the CNTs' detachment from the Si core during cycling. The multifunctional structural design rendered the whole electrode highly stable and active in Li storage, and the electrochemically active NCNTs-Ni2Si@Si electrode delivered a high reversible capacity of 1547 mAh g-1 and excellent cycling stability (85% capacity retention after 600 discharge-charge cycles) at a current density of 358 mA g-1 (0.1 C) as well as good rate performance (778 mAh g-1 at 2 C), showing great potential as an efficient and stable anode for high energy density Li-ion batteries.

Strategic Design of Vacancy-Enriched Fe1- xS Nanoparticles Anchored on Fe3C-Encapsulated and N-Doped Carbon Nanotube Hybrids for High-Efficiency Triiodide Reduction in Dye-Sensitized Solar Cells.

A new class of hybrids with the unique electrocatalytic nanoarchitecture of Fe1- xS anchored on Fe3C-encapsulated and N-doped carbon nanotubes (Fe1- xS/Fe3C-NCNTs) is innovatively synthesized through a facile one-step carbonization-sulfurization strategy. The efficient synthetic protocols on phase structure evolution and dynamic decomposition behavior enable the production of the Fe1- xS/Fe3C-NCNT hybrid with advanced structural and electronic properties, in which the Fe vacancy-contained Fe1- xS showed the 3d metallic state electrons and an electroactive Fe in +2/+3 valence, and the electronic structure of the CNT was effectively modulated by the incorporated Fe3C and N, with the work function decreased from 4.85 to 4.63 eV. The meticulous structural, electronic, and compositional control unveils the unusual synergetic catalytic properties for the Fe1- xS/Fe3C-NCNT hybrid when developed as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), in which the Fe3C- and N-incorporated CNTs with reduced work function and increased charge density provide a highway for electron transport and facilitate the electron migration from Fe3C-NCNTs to ultrahigh active Fe1- xS with the electron-donating effect, and the Fe vacancy-enriched Fe1- xS nanoparticles exhibit ultrahigh I3- adsorption and charge-transfer ability. As a consequence, the DSSC based on the Fe1- xS/Fe3C-NCNT CE delivers a high power conversion efficiency of 8.67% and good long-term stability with a remnant efficiency of 8.00% after 168 h of illumination, superior to those of traditional Pt. Furthermore, the possible catalytic mechanism toward I3- reduction is creatively proposed based on the structure-activity correlation. In this work, the structure engineering, electronic modulation, and composition control opens up new possibilities in constructing the novel electrocatalytic nanoarchitecture for highly efficient CEs in DSSCs.

Reductive chemical release of N-glycans as 1-amino-alditols and subsequent 9-fluorenylmethyloxycarbonyl labeling for MS and LC/MS analysis.

Glycoproteins play pivotal roles in a series of biological processes and their glycosylation patterns need to be structurally and functionally characterized. However, the lack of versatile methods to release N-glycans as functionalized forms has been undermining glycomics studies. Here a novel method is developed for dissociation of N-linked glycans from glycoproteins for analysis by MS and online LC/MS. This new method employs aqueous ammonia solution containing NaBH3CN as the reaction medium to release glycans from glycoproteins as 1-amino-alditol forms. The released glycans are conveniently labeled with 9-fluorenylmethyloxycarbonyl (Fmoc) and analyzed by ESI-MS and online LC/MS. Using the method, the neutral and acidic N-glycans were successfully released without peeling degradation of the core α-1,3-fucosylated structure or detectable de-N-acetylation, revealing its general applicability to various types of N-glycans. The Fmoc-derivatized N-glycans derived from chicken ovalbumin, Fagopyrum esculentum Moench Pollen and FBS were successfully analyzed by online LC/MS to distinguish isomers. The 1-amino-alditols were also permethylated to form quaternary ammonium cations at the reducing end, which enhance the MS sensitivity and are compatible with sequential multi-stage mass spectrometry (MSn) fragmentation for glycan sequencing. The Fmoc-labeled N-glycans were further permethylated to produce methylated carbamates for determination of branches and linkages by sequential MSn fragmentation. SIGNIFICANCE OF THE STUDY: N-Glycosylation represents one of the most common post-translational modification forms and plays pivotal roles in the structural and functional regulation of proteins in various biological activities, relating closely to human health and diseases. As a type of informational molecule, the N-glycans of glycoproteins participate directly in the molecular interactions between glycan epitopes and their corresponding protein receptors. Detailed structural and functional characterization of different types of N-glycans is essential for understanding the functional mechanisms of many biological activities and the pathologies of many diseases. Here we describe a simple, versatile method to indistinguishably release all types of N-glycans as functionalized forms without remarkable side reactions, enabling convenient, rapid analysis and preparation of released N-glycans from various complex biological samples. It is very valuable for studies on the complicated structure-function relationship of N-glycans, as well as for the search of N-glycan biomarkers of some major diseases and N-glycan related targets of some drugs.

Metabolic Redesign of Rhodobacter sphaeroides for Lycopene Production.

Lycopene plays an important role as an antioxidative and anticancer agent, and is an increasingly valuable commodity in the global market. Rhodobacter sphaeroides, a carotenogenic and phototrophic bacterium, is an efficient and practical host for carotenoid production. Herein, we explored the potential of metabolically engineered Rb. sphaeroides as a novel platform to produce lycopene. The basal lycopene-producing strain was generated by introducing an exogenous crtI4 from Rhodospirillum rubrum to replace the native crtI3 and deleting crtC in Rb. sphaeroides. Furthermore, knocking out zwf blocked the competitive pentose phosphate pathway and improved the lycopene content by 88%. Finally, the methylerythritol phosphate pathway was reinforced by integration of dxs combined with zwf deletion, which further increased the lycopene content. The final engineered strain produced lycopene to 10.32 mg/g dry cell weight. This study describes a new lycopene producer and provides insight into a photosynthetic bacterium as a host for lycopene biosynthesis.

Phosphonate-Stabilized Titanium-Oxo Clusters with Ferrocene Photosensitizer: Structures, Photophysical and Photoelectrochemical Properties, and DFT/TDDFT Calculations.

The metal-to-core charge transfer (MCCT) transition in sensitized titanium-oxo clusters is an important process for photoinduced electron injection in photovoltaic conversion. This process resembles most closely the Type II photoinjection in dye-sensitized solar cells. Herein we report the synthesis and photophysical and photoelectrochemical (PEC) properties of the phosphonate-stabilized titanium-oxo clusters containing the ferrocenecarboxylate ligands. These ferrocene-containing clusters exhibit intense visible absorption extended up to 600 nm along with low optical band gaps of ∼2.2 eV. The low-energy transitions of these clusters were systematically investigated by UV-vis spectroscopy and DFT/TDDFT calculations. The combined experimental and computational studies suggest that the ferrocenecarboxylate-substituted titanium-oxo clusters form a donor-acceptor (D-A) system. The low-energy transition of these clusters primarily involves the MCCT from the iron center to TiO cluster core. The TiO core structure and phosphonate ligands both have great influence on the PEC properties of the clusters. This work provides valuable examples for the sensitized titanium-oxo clusters in which electron injection takes place via MCCT transition.

A 4-dimethylaminobenzoate-functionalized Ti6-oxo cluster with a narrow band gap and enhanced photoelectrochemical activity: a combined experimental and computational study.

Organic donor-π-bridge-acceptor (D-π-A) dyes with arylamines as an electron donor have been widely used as photosensitizers for dye-sensitized solar cells (DSSCs). However, titanium-oxo clusters (TOCs) functionalized with this kind of D-π-A structured dye-molecule have rarely been explored. In the present study, the 4-dimethylaminobenzoate-functionalized titanium-oxo cluster [Ti6(µ3-O)6(OiPr)6(DMABA)6]·2C6H5CH3 (DMABA = 4-dimethylaminobenzoate) was synthesized and structurally characterized by single-crystal X-ray diffraction. For comparison, two other Ti6-oxo clusters, namely [Ti6(µ3-O)6(OiPr)6(AD)6] (AD = 1-adamantanecarboxylate) and [Ti6(µ3-O)2(µ2-O)(µ2-OiPr)4(OiPr)10(DMM)2] (DMM = dimethylmalonate), were also studied. The DMABA-functionalized cluster exhibits a remarkably reduced band gap of ∼2.5 eV and much enhanced photocurrent response in comparison with the other two clusters. The electronic structures and electronic transitions of the clusters were studied by DFT and TDDFT calculations. The computational results suggest that the low-energy transitions of the DMABA-functionalized cluster have a substantial charge-transfer character arising from the DMABA → {Ti6} cluster core ligand-to-core charge transfer (LCCT), along with the DMABA-based intra-ligand charge transfer (ILCT). These low-energy charge transfer transitions provide efficient electron injection pathways for photon-to-electron conversion.

A ferrocenecarboxylate-functionalized titanium-oxo-cluster: the ferrocene wheel as a sensitizer for photocurrent response.

Sensitized titanium-oxo clusters (TOCs) have attracted growing interest. However, reports on TOCs incorporated with a metal complex as photosensitizers are still very rare. In the present work, the organometallic complex ferrocene was used as a sensitizer for a titanium-oxo cluster. A ferrocenecarboxylate-substituted titanium-oxo cluster [Ti6(µ3-O)6(OiPr)6(O2CFc)6] (Fc = ferrocenyl) was synthesized and structurally characterized, in which the ferrocene wheel performs as a sensitizer for photocurrent response. For comparison, naphthalene-sensitized titanium-oxo clusters [Ti6(µ3-O)6(OiPr)6(NA)6] (NA = 1-naphthoate) and [Ti6(µ3-O)6(OiPr)6(NAA)6] (NAA = 1-naphthylacetate) with the same {Ti6} core structure were also synthesized. The structures, optical behaviors, electronic states and photoelectrochemical properties of these sensitized {Ti6} clusters were investigated. It is demonstrated that the introduction of ferrocene groups into the titanium-oxo cluster significantly reduces the band gap and enhances the photocurrent response in comparison with the naphthalene-sensitized clusters. The substantially reduced band gap of the ferrocene-sensitized cluster was attributed to the introduction of Fe(ii) d-d transitions and the possible contribution from the Fc → {Ti6} charge transfer. For the naphthalene-sensitized clusters, the better electronic coupling between the dye and the {Ti6} core in the 1-naphthoate (NA) substituted cluster results in higher photoelectrochemical activity.

Enhancement of X-ray Induced Apoptosis by Mobile Phone-Like Radio-Frequency Electromagnetic Fields in Mouse Spermatocyte-Derived Cells.

To explore the combined effects of environmental radio-frequency (RF) field and X-ray, mouse spermatocyte-derived (GC-1) cells were exposed to 1950 MHz RF field at specific absorption rate (SAR) of 3 W/kg for 24 h combined with or without X-ray irradiation at 6 Gy. After treatment, the cell proliferation level was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) Assay and 5-Bromo-2-deoxy Uridine (BrdU) enzyme linked immunosorbent (ELISA) Assay. The apoptosis level was detected by annexin V flow cytometry assay, transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) Assay and Caspase-3 Activity Assay. It was found that the proliferation and apoptosis level did not change in GC-1 cells after RF exposure alone. However, compared with the X-ray group, the proliferation level significantly decreased and the apoptotic rate significantly increased in the RF+X-ray group. Moreover, a significant decrease in Bcl-2 protein expression and increase in Bax protein expression were observed. The findings suggested that RF exposure at SAR of 3 W/kg did not affect apoptosis and proliferation in GC-1 cells by itself, but that it did enhance the effects of X-ray induced proliferation inhibition and apoptosis, in which B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) might be involved.

General Strategy for Controlled Synthesis of NixPy/Carbon and Its Evaluation as a Counter Electrode Material in Dye-Sensitized Solar Cells.

Hydrothermal treatment of nickel acetate and phosphoric acid aqueous solution followed with a carbothermal reduction assisted phosphorization process using sucrose as the carbon source for the controlled synthesis of NixPy/C was successfully realized for the first time. The critical synthesis factors, including reduction temperature, phosphorus/nickel ratio, pH, and sucrose amount were systematically investigated. Remarkably, the carbon serves as a reducer and plays a determinative role in the transformation of Ni2P2O7 into Ni2P/C. The synthesis strategy is divided into four distinguishable stages: (1) hydrothermal preparation of Ni3(PO4)2·8H2O precursor for stabilizing P sources; (2) dimerization of Ni3(PO4)2·8H2O into more thermal stable Ni2P2O7 amorphous phase along with the generation of NiO; (3) carbothermal reduction and phosphidation of NiO into NixPy (0 ≤ y/x ≤ 0.5); and (4) further phosphidation of mixed-phase NixPy and carbothermal reduction of Ni2P2O7 into single-phase Ni2P. The resultant Ni2P, the highly active phase in electrocatalysis, was applied as counter electrode in a dye-sensitized solar cell (DSSC). The DSSC based on Ni2P with 10.4 wt.% carbon delivers a power conversion efficiency of 9.57%, superior to that of state-of-the-art Pt-based cell (8.12%). The abundant Niδ+ and Pδ- active sites and the metal-like conductivity account for its outstanding catalytic performance.

Quantitative O-glycomics based on improvement of the one-pot method for nonreductive O-glycan release and simultaneous stable isotope labeling with 1-(d0/d5)phenyl-3-methyl-5-pyrazolone followed by mass spectrometric analysis.

Rapid, simple and versatile methods for quantitative analysis of glycoprotein O-glycans are urgently required for current studies on protein O-glycosylation patterns and the search for disease O-glycan biomarkers. Relative quantitation of O-glycans using stable isotope labeling followed by mass spectrometric analysis represents an ideal and promising technique. However, it is hindered by the shortage of reliable nonreductive O-glycan release methods as well as the too large or too small inconstant mass difference between the light and heavy isotope form derivatives of O-glycans, which results in difficulties during the recognition and quantitative analysis of O-glycans by mass spectrometry. Herein we report a facile and versatile O-glycan relative quantification strategy, based on an improved one-pot method that can quantitatively achieve nonreductive release and in situ chromophoric labeling of intact mucin-type O-glycans in one step. In this study, the one-pot method is optimized and applied for quantitative O-glycan release and tagging with either non-deuterated (d0-) or deuterated (d5-) 1-phenyl-3-methyl-5-pyrazolone (PMP). The obtained O-glycan derivatives feature a permanent 10-Da mass difference between the d0- and d5-PMP forms, allowing complete discrimination and comparative quantification of these isotopically labeled O-glycans by mass spectrometric techniques. Moreover, the d0- and d5-PMP derivatives of O-glycans also have a relatively high hydrophobicity as well as a strong UV adsorption, especially suitable for high-resolution separation and high-sensitivity detection by RP-HPLC-UV. We have refined the conditions for the one-pot reaction as well as the corresponding sample purification approach. The good quantitation feasibility, reliability and linearity of this strategy have been verified using bovine fetuin and porcine stomach mucin as model O-glycoproteins. Additionally, we have also successfully applied this method to the quantitative O-glycomic comparison between perch and salmon eggs by ESI-MS, MS/MS and online RP-HPLC-UV-ESI-MS/MS, demonstrating its excellent applicability to various complex biological samples. BIOLOGICAL SIGNIFICANCE: O-Linked glycoproteins, generated via a widely existing glycosylation modification process on serine (Ser) or threonine (Thr) residues of nascent proteins, play essential roles in a series of biological processes. As a type of informational molecule, the O-glycans of these glycoproteins participate directly in these biological mechanisms. Thus, the characteristic differences or changes of O-glycans in expression level usually relate to pathologies of many diseases and represent an important opportunity to uncover the functional mechanisms of various glycoprotein O-glycans. The novel strategy introduced here provides a simple and versatile analytical method for the precise quantitation of glycoprotein O-glycans by mass spectrometry, enabling rapid evaluation of the differences or changes of O-glycans in expression level. It is attractive for the field of quantitative/comparative O-glycomics, which has great significance for exploring the complex structure-function relationship of O-glycans, as well as for the search of O-glycan biomarkers of some major diseases and O-glycan related targets of some drugs.