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The construction of an anode material with a conversion-alloying dual mechanism will facilitate the development of potassium-ion batteries (PIBs) with high-energy density. Here a Bi2Se3 nanosheets coated with nitrogen-doped carbon and wrapped with reduced graphene oxide (Bi2Se3@NC@rGO) is fabricated to boost K-ion storage. The Bi2Se3@NC@rGO composite with strong C–O–Bi bonding can provide superior electrode integrity and electrochemical kinetics by combining the synergistic effect of carbon encapsulation and graphene confinement. In situ X-ray diffraction and ex situ transmission electron microscopy analyses demonstrate that K-ion intercalation/deintercalation proceeds via both conversion and alloying/dealloying reactions based on 12-electron transfer per formula unit; the conversion product of K2Se can efficiently suppress the volume expansion during alloying/dealloying process to improve its stability. Hence, a high reversible capacity of 612.0 mAh·g−1 at 100 mA·g−1; a great rate capability with the capacity of 101.6 mAh·g−1 at 5 A·g−1, and an ultra-long cycling life of over 1000 cycles at 500 mA·g−1 is achieved for the Bi2Se3@NC@rGO. The K-ion full cell is also assembled using K2Ni[Fe(CN)6] as the cathode, thereby contributing a high-energy density of 162.9 Wh·kg−1 at 10 mA·g−1 and a great cyclability.

Conversion-alloying dual mechanism anode materials have become the research hotspot for potassium-ion batteries (PIBs) due to its high theoretical specific capacity and low operating voltage. However, the large volume expansion and sluggish dynamic behavior are still the key bottleneck to suppress its further development. Herein, Sb2S3 nanorods encapsulated by reduced graphene oxide and nitrogen-doped carbon (Sb2S3@rGO@NC) are constructed as anodes for PIBs. The synergistic effect of dual physical protection and robust C-Sb chemical bonding between Sb2S3 and graphene boosts superior electrochemical kinetics behavior and great electrode stability to buffer the huge lattice stress. As a result, Sb2S3@rGO@NC composite exhibits a high initial charge capacity of 505.6 mAh·g-1 at 50 mA·g-1 and a great cycle stability with the lifetime over 200 cycles at 200 mA·g-1. Ex situ XRD, XPS and TEM characterizations confirm that the electrode undergoes a multi-electron transfer process (Sb2S3 ↔ Sb + K2S ↔ KSb + K3Sb) based on the redox center of Sb-ion, where K-ion insert into/extract from the material via dual mechanisms of conversion and alloying. This work sheds a light on the construction of high-performance anode materials and the understanding of K-ion storage mechanism.

SUMMARY The large volume expansion and sluggish dynamic behavior are the key bottleneck to suppress the development of conversion-alloying dual mechanism anode for potassium-ion batteries (PIBs). Herein, Sb2S3 nanorods encapsulated by reduced graphene oxide and nitrogen-doped carbon (Sb2S3@rGO@NC) are constructed as anodes for PIBs. The synergistic effect of dual physical protection and robust C-Sb chemical bonding boosts superior electrochemical kinetics and great electrode stability. Thus, Sb2S3@rGO@NC exhibits a high initial charge capacity of 505.6 mAh·g-1 at 50 mA·g-1 and a great cycle stability with the lifetime over 200 cycles at 200 mA·g-1. Ex situ XRD, XPS and TEM characterizations confirm that the electrode undergoes a multi-electron transfer process (Sb2S3 ↔ Sb + K2S ↔ KSb + K3Sb), where K-ion insert into/extract from the material via dual mechanisms of conversion and alloying. This work sheds a light on the construction of high-performance anode materials and the understanding of K-ion storage mechanism.

To remove As(III) in water, the composite material of TiO2@ZIF-8 was prepared by a sol-gel method with zeolitic imidazolate framework-8 (ZIF-8) as the matrix. The structure of TiO2@ZIF-8 was characterized with scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The results indicated that the best loading efficiency of TiO2 on ZIF-8 occurred when it was calcined at 300 °C for 3 h. This material was used to remove As(III) from aqueous solution, and the effect of the initial concentration of As(III), pH, and the illumination condition on the removal of As(III) was investigated. The results showed that the removal rate of As(III) was as high as 100% under a pH of 4–7, an initial As(III) concentration of less than 2 mg/L, and UV-light irradiation for 2 h. The repeated experiments were also performed for the investigation of the stability of TiO2@ZIF-8.

As an antioxidant, glutathione (GSH) can react with reactive oxygen species (ROS) and heavy metals to help alleviate oxidative stress (OS) and damage in cells. Accurately measuring the GSH level is important to gauge the integrity of cell redox buffering capacity. In this work, a convenient method for qualitative and quantitative determination of GSH was developed based on the reaction between CoOOH nanosheets and 3,3′,5,5′-tetramethylbenzidine (TMB). Colorless TMB solution can be oxidized by CoOOH to oxidized TMB (oxTMB) which is blue in color. However, in the presence of GSH, CoOOH preferentially reacted with GSH, producing less oxTMB and lighting the blue color. The changes of the blue color of oxTMB can be directly observed by naked eyes and accurately measured by UV–vis absorbance at 652 nm. Based on that, GSH can be detected in a wide range from 0.1 to 300 µM with a low limit of detection of 0.08 μM which was performed with a quantitative high-throughput 96-well plate. In addition, GSH in human SH-SY5Y neuroblastoma cells was successfully determined using our method, and the results show excellent agreement with those measured by a commercial GSH detection kit based on the use of Ellman’s reagent.

Background. With the change in lifestyle and the aging population, the incidence of cognitive dysfunction in diabetes mellitus is rising sharply. Oxidative stress is an important mechanism in the development of diabetic cognitive dysfunction. Nuclear factor E2-related factor 2 (Nrf2) is the core transcription factor of antioxidative stress. Early prevention and treatment of diabetic cognitive dysfunction can reduce the incidence of dementia and improve the quality of life of diabetic patients.Aim. This study was aimed at determining effect of troxerutin on the development of cognitive dysfunction and the expression level of Nrf2 in the hippocampus of streptozotocin (STZ) diabetic rats, when used in the early preventive stage.Methods. An STZ-induced diabetic rat model was established (n=30), and the animals were randomly divided into 2 groups: diabetic control group (DC,n=15) and diabetic troxerutin intervention group (DT,n=15). Another 10 normoglycemic rats were put into a normal control group (NC,n=10). While the DT group was injected with troxerutin (60 mg/kg), the DC group and the NC group were injected with physiological saline for 12 weeks daily. Learning and memory behaviors were tested using the Morris water maze test. The superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, mRNA level, and protein level of Nrf2 were measured. Data were collected and analyzed by the statistical software package SPSS 19.0, which included one-way analysis of variance with completely randomized design.Results. Learning and memory levels were significantly improved in the DT group compared with the DC group. Moreover, in the DT group, the expression level of Nrf2 in the hippocampus was increased, activity of SOD was elevated, and MDA content was decreased.Conclusion. Prophylactic use of troxerutin delays the development of diabetic cognitive dysfunction and increases the expression level of Nrf2 in the hippocampus of STZ diabetic rats.

In order to improve the adsorption and photocatalytic performance of TiO 2 modified clay composite, a new method of immobilization of nano-scaled TiO 2 on the layer surface of montmorillonite (MT) clay was designed and carried out in two steps in this work. The first step was to prepare a nano-scaled TiO 2 dispersion by a hydrothermal method with the addition of organic dispersant into an aqueous solution of TiCl 4 ; and then the assemblies of nano-scaled TiO 2 with CTAB (cetyltrimethylammonium bromide) were applied to regulate the process of immobilization of nano-scaled TiO 2 on the layer surface of MT clay. The results indicated that well pre-dispersed nano-TiO 2 was obtained with the application of diethanolamine (DEA) as a dispersant, which could interact with CTAB to form assemblies of nano-scaled TiO 2 particles and CTAB molecules (CTAB–DEA–TiO 2 ), and then became self-anchored on the layer surface of MT clay to produce well-distributed TiO 2 /MT nanocomposites. After calcination at 500 °C, the modified composites showed much higher values for specific surface area, average pore size and pore volume than the raw MT clay. The adsorption and photocatalytic performance of the composite TCM-500 was evaluated by using methyl orange (MO). The comparative photocatalytic degradation of MO indicated that the composite gave 10% higher photocatalytic efficiency than P25 due to its optimal structural conformation tailored by surfactant assembly. Therefore, the new method of immobilization of pre-dispersed nano-scaled TiO 2 assembly with a surfactant was a good alternative to prepare a TiO 2 /MT nanocomposite and was effective to improve its adsorption capacity and photocatalytic performance.

A simple and fast method was developed to determine non-UV active compounds directly without derivatization. The usefulness of the method was demonstrated by detecting the major components in aminoglycoside antibiotic mixtures using capillary zone electrophoresis with potential gradient detection. Under optimized separation conditions (0.2 mM cetyltrimethylammonium bromide (CTAB), 1 mM ammonium citrate, pH 3.5), gentamicin was separated into three major peaks (C1, C1a, and C2+C2a) within 15 min. This method showed better sensitivity than other capillary electrophoresis (CE) methods for determining underivatized gentamicin. The linear range was from 10 to 500 ppm. Because of its good repeatability and simplicity, this new method could be a good alternative for the current assays given by US Pharmacopoeia and European Pharmacopoeia.

High-performance capillary electrophoresis (HPCE) has been applied to the identification, separation, and quantitation of intact bacteria. We demonstrate that a pathogen (Edwardsiella tarda) which causes systemic infection in commercially important fish species can be rapidly identified and determined (10 min) after direct injection into fish fluid by CE blue light-emitting diode (LED)-induced fluorescence. SYTO 13 (488 nm/509 nm), a cell-permeable green nucleic acid stain, was used to stain the cells. Remarkably high efficiency (1,200,000 theoretical plates/m) was achieved with this rapid and efficient CE method. It was found that proper sample vortexing (90 s) would be beneficial to disperse aggregated cells and facilitate the focusing of intact cells during electrophoresis. Ionization of the surface constituents of Edwardsiella tarda cells provided efficient surface charges for the intact cells to be separated from the EOF and damaged or lysed cells when the separation was performed in running buffer (3.94 mM Tris, 0.56 mM borate, 0.013 mM EDTA) at pH 10.5. The limit of detection (LOD) and recovery were found to be 4.2 x 10(4) cells/mL and 70.0%, respectively. This proposed CE method could become an effective tool for diagnosis and tracking of certain diseases caused by bacteria in fish species as well as in human beings.

In Chinese medicines, herbs are usually prepared before use by patients. Since the preparation procedures convert the original component into one or more products, study of the procedures is usually complex and involves several compounds. On-line coupling of capillary electrophoresis (CE) to mass spectrometry (MS) allows both the efficient separation of CE and the specific and sensitive detection of MS to be achieved. In this study, CE-MS was applied to the determination of alkaloids in Maqianzi (the seed of Strychnos pierrian) and Wutou (aconite root, Radix aconiti praeparata) during the preparation procedure. With optimal CE-MS conditions, alkaloids in both prepared and unprepared Maqianzi were determined successfully in the total ion current (TIC) mode. However, single ion monitoring (SIM) had to be applied for the separation of aconitum alkaloids and their hydrolysis products. Quantification data indicated that MS detection under SIM mode is more sensitive than UV detection. Based on the CE-MS method developed, the hydrolysis of aconitum alkaloids in water and methanol was also studied.

The immobilization of pre-dispersed TiO2 colloids onto the external surface of the clay mineral montmorillonite (Mt) was accomplished and regulated via a self-assembly method employing the cationic surfactant cetyltrimethylammonium bromide (CTAB). The role of CTAB in the synthesis process was investigated by preparing a series of TiO2-CTAB-Mt composites (TCM) with various CTAB doses. The results indicated that a uniform and continuous TiO2 film was deposited on the external surface of montmorillonite in the composite synthesized with 0.1 wt.% of CTAB, and the TCM nano-composites showed much higher values for specific surface area, average pore size and pore volume than the raw montmorillonite clay. Then, the formed TCM materials were applied in photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) in aqueous solution. The degradation efficiency reached as high as 94.7%. Based on the degradation intermediates benezoquinone, fumaric acid and oxalic acid identified by LC-MS analysis, a mechanism for the photocatalytic oxidation of 2,4-DCP on TiO2/Mt nano-composites is proposed.

Sustainable food production for the earth's fast-growing population is a major challenge for breeding new high-yielding crops, but enhancing the nutritional quality of staple crops can potentially offset limitations associated with yield increases. Sorghum has immense value as a staple food item for humans in Africa, but it is poorly digested. Although a mutant exhibiting high-protein digestibility and lysine content has market potential, the molecular nature of the mutation is previously unknown. Here, building on knowledge from maize mutants, we take a direct approach and find that the high-digestible sorghum phenotype is tightly linked to a single-point mutation, rendering the signal peptide of a seed storage protein kafirin resistant to processing, indirectly reducing lysine-poor kafirins and thereby increasing lysine-rich proteins in the seeds. These findings indicate that a molecular marker can be used to accelerate introduction of this high nutrition and digestibility trait into different sorghum varieties.

This study investigates the effects of osmopriming on tomato (Lycopersicon esculentum M.) hybrid seed vigor under aging and salinity stress. Tomato seeds of the ZZ1 hybrid variety, stored for four years under natural (aged) or -20°C (unaged) conditions were primed in 10% (w/v) polyethylene glycol (PEG) solution for 2 d at 20±1°C in the dark. The seed vigor was evaluated at 25±1°C for 7 d under normal (water) and 100 mM NaCl conditions, respectively. Results show that the germination percentage (GP), germination index (GI) and mean germination rate (MGR) of primed, aged seeds were significantly enhanced with a substantial increase in the radicle length (RL), shoot length (SL) and total fresh weight (FW) compared with unprimed aged seeds. Similarly, the GI, MGR and FW significantly increased in primed seeds compared with unprimed seeds under salinity stress, while GP, RL and SL did not show significant differences. Furthermore, a decline in the relative electrolyte leakage (REL) and in malondialdehyde (MDA) was detected in primed seeds during the imbibition stage compared with unprimed seeds under aging and salinity stress. The negative correlations between seed vigor and REL and MDA were observed which suggests that seed priming improves seed vigor under stress conditions associated with a decrease in seed lipid peroxidation.Key words: Tomato, seed priming, osmopriming, seed vigor, seed aging, salt tolerance.

A simple method based on capillary electrophoresis with potential gradient detection was developed to separate and detect neomycin components within 4 min without a derivatization step. Satisfactory separation and good repeatability were obtained using a separation buffer composed of 1 mM ammonium citrate (pH 3.5). The linearity of the method ranged from 10 to 1000 ppm with a limit of detection for neomycin B of about 7 ppm. After a simple dilution and filtering pretreatment step, neomycin components in three real samples were successfully analyzed without any major interference. Due to its simplicity and reliability, this method could provide an excellent alternative to the assays currently listed in U.S. and European Pharmacopoeia. The experiments were performed on a portable capillary electrophoresis system and, hence, the method can be readily applied to field analysis and point-of-care testing. Figure Photo of portable CE-P2-PGD system.

A modified field amplification sample injection method was proposed and evaluated by using positively mono charged cyclodextrin (CD) as carrier and 1-adamantanecarboxylate as displacer for on-capillary preconcentration of neutral compounds and improvement of the concentration limit of detection in micellar electrokinetic chromatography. In modified sample injection mode a displacer plug was introduced before sample injection to reduce the length of the concentrated sample zone and increase the peak height by slowing down the forward movement of the neutral sample associated with β-CD-NH2 and the backward movement of the neutral sample partitioned in the micelles of sodium dodecyl sulfate. Stability of the inclusion complexes formed between the carrier and the solute was found to be an important factor affecting stacking efficiency in both the conventional field amplification sample injection mode and the modified one. However, further enhancement of the stacking efficiency in the modified mode rested on the relative stability of the displacer–carrier complex to that of the solute–carrier complex. Practical limits to the stacking efficiencies in both modes were discussed as well.