Three-dimensional honeycomb-like porous carbon derived from corncob for the removal of heavy metals from water by capacitive deionization

In this study, porous carbon (3DHPC) with a 3D honeycomb-like structure was synthesized from waste biomass corncob via hydrothermal carbonization coupled with KOH activation and investigated as a capacitive deionization (CDI) electrode material. The obtained 3DHPC possesses a hierarchal macroporous and mesoporous structure, and a large accessible specific surface area (952 m² g⁻¹). Electrochemical tests showed that the 3DHPC electrode exhibited a specific capacitance of 452 F g⁻¹ and good electric conductivity. Moreover, the feasibility of electrosorptive removal of chromium(vi) from an aqueous solution using the 3DHPC electrode was demonstrated. When 1.0 V was applied to a solution containing 30 mg L⁻¹ chromium(vi), the 3DHPC electrode exhibited a higher removal efficiency of 91.58% compared with that in the open circuit condition. This enhanced adsorption results from the improved affinity between chromium(vi) and the electrode under electrochemical assistance involving a non-faradic process. Consequently, the 3DHPC electrode with typical double-layer capacitor behavior is demonstrated to be a favorable electrode material for capacitive deionization.

A porous carbon electrode with a 3D honeycomb-like structure demonstrates a high removal efficiency for the removal of chromium(vi) from water.     

Illustration of charge transfer in graphene-coated hexagonal ZnO photocatalysts using Kelvin probe force microscopy

A graphene coated hexagonal ZnO (HZO@Gr) with enhanced activity in photocatalysis was synthesized. However, the photoinduced charge transfer behavior and the beneficial role of graphene in promoting photocatalytic reactions have not been sufficiently investigated experimentally. In this paper, the surface potentials of the ±(0001)-polar plane of HZO (Zn-polar plane and O-polar plane), graphene, graphene/Zn-polar plane and graphene/O-polar plane were measured using Kelvin probe force microscopy (KPFM). On the basis of the KPFM results, the respective Fermi levels were calculated and the internal electric field (IEF) of HZO was confirmed. Taking the IEF of HZO into consideration, the three-dimensional band diagrams of the HZO@Gr composites in methyl blue (MB) solution in the dark and under UV-visible irradiation after equilibrium were proposed. Accordingly, it is found that there could emerge different interactions between graphene and HZO at the ±(0001)-polar plane of HZO. Furthermore, the photogenerated holes and electrons tend to migrate to opposite directions. With the participation of graphene and IEF, the composites show a decrease in possibility of charge recombination. As a result, the active groups, namely ˙OH and ˙O₂⁻ radicals, could be mainly generated at/near the O-polar plane and Zn-polar plane, respectively. This work can serve as a supplemental explanation of the charge transfer during the photocatalytic process at the polar ZnO/graphene composite surface.

The Fermi levels and three-dimensional band diagrams of the synthesized HZO@Gr composites in methyl blue (MB) solution before and after equilibrium were assumed.     

Preferential occupancy of Eu3+ and energy transfer in Eu3+ doped Sr2V2O7, Sr9Gd(VO4)7 and Sr2V2O7/Sr9Gd(VO4)7 phosphors

The vanadate-based phosphors Sr₂V₂O₇:Eu³⁺ (SV:Eu³⁺), Sr₉Gd(VO₄)₇:Eu³⁺ (SGV:Eu³⁺) and Sr₉Gd(VO₄)₇/Sr₂V₂O₇:Eu³⁺ (SGV/SV:Eu³⁺) were obtained by solid-state reaction. The bond-energy method was used to investigate the site occupancy preference of Eu³⁺ based on the bond valence model. By comparing the change of bond energy when the Eu³⁺ ions are incorporated into the different Sr, V or Gd sites, we observed that Eu³⁺ doped in SV, SGV or SV/SGV would preferentially occupy the smaller energy variation sites, i.e., Sr4, Gd and Gd sites, respectively. The crystal structures of SGV and SV, the photoluminescence properties of SGV:Eu³⁺, SV, SGV/SV and SGV/SV:Eu, as well as their possible energy transfer mechanisms are proposed. Interesting tunable colours (including warm-white emission) of SGV/SV:Eu³⁺ can be obtained through changing the concentration of Eu³⁺ or changing the relative quantities of SGV to SV by increasing the calcination temperature. Its excitation bands consist of two types of O²⁻ → V⁵⁺ charge transfer (CT) bands with the peaks at about 325 and 350 nm respectively, as well as f–f transitions of Eu³⁺. The obtained warm-white emission consists of a broad photoluminescence band centred at about 530 nm, which originates from the O²⁻ → V⁵⁺ CT of SV, and a sharp characteristic spectrum (⁵D₀–⁷F₂) at about 615 and 621 nm.

The vanadate-based phosphors Sr₂V₂O₇:Eu³⁺ (SV:Eu³⁺), Sr₉Gd(VO₄)₇:Eu³⁺ (SGV:Eu³⁺) and Sr₉Gd(VO₄)₇/Sr₂V₂O₇:Eu³⁺ (SGV/SV:Eu³⁺) were obtained by solid-state reaction.     

Feedback Facility−Assisted Balance Training in a Patient With Multiple System Atrophy: A Case Presentation

Multiple system atrophy is a rare neurodegenerative disease with a poor prognosis. Furthermore, there are no pharmacological or notable rehabilitation strategies available to prevent the worsening of the disease. This case presentation assessed the outcome of feedback facility?assisted balance training in combination with physical therapy in a 61-year-old man. The patient participated in 30 training sessions over 6 weeks for 30 minutes each that involved balance training. His static and dynamic balance abilities were improved on the Berg Balance Scale, Trunk Impairment Scale, Functional Independence Measure, and Functional Reach. Although this patient’s gait speed and muscle strength did not show improvement after training, feedback facility?assisted balance training might be a potential strategy to help reduce the rate of symptom deterioration in patients with multiple system atrophy.

Alpha 1 antitrypsin distribution in an allergic asthmatic population sensitized to house dust mites

Background and objective

Severe alpha1 antitrypsin deficiency has been clearly associated with pulmonary emphysema, but its relationship with bronchial asthma remains controversial. Some deficient alpha 1 antitrypsin (AAT) genotypes seem to be associated with asthma development. The objective of this study was to analyze the distribution of AAT genotypes in asthmatic patients allergic to house dust mites (HDM), and to asses a possible association between these genotypes and severe asthma.

Methods

A cross-sectional cohort study of 648 patients with HDM allergic asthma was carried out. Demographic, clinical and analytical variables were collected. PI*S and PI*Z AAT deficient alleles of the SERPINA1 gene were assayed by real-time PCR.

Results

Asthma was intermittent in 253 patients and persistent in 395 patients (246 mild, 101 moderate and 48 severe). One hundred and forty-five asthmatic patients (22.4%) with at least one mutated allele (S or Z) were identified. No association between the different genotypes and asthma severity was found. No significant differences in all clinical and functional tests, as well as nasal eosinophils, IgA and IgE serum levels were observed. Peripheral eosinophils were significantly lower in patients with the PI*MS genotype (p?=?0.0228). Neither association between deficient AAT genotypes or serum ATT deficiency (AATD) and development of severe asthma, or correlation between ATT levels and FEV1 was observed.

Conclusion

In conclusion, the distribution of AAT genotypes in HDM allergic asthmatic patients did not differ from those found in Spanish population. Neither severe ATTD or deficient AAT genotypes appear to confer different clinical expression of asthma.

     

Novel N-doped ZrO2 with enhanced visible-light photocatalytic activity for hydrogen production and degradation of organic dyes

Two new types of N-doped ZrO₂ photocatalysts ZON and AZON have been synthesized using ethylenediamine as the nitrogen source by a facile and low-cost sol–gel method. The N-doped ZrO₂ samples have been characterized using various techniques including X-ray diffraction (XRD), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and N₂ adsorption–desorption tests. The XRD analysis shows that the crystallinity of ZON samples calcined at 400–600 °C can be indexed to monoclinic ZrO₂; while the AZON samples calcined at 400–550 °C only show amorphous diffraction patterns. The UV-Vis response of both N-doped ZrO₂ samples can be extended to the visible light regime. The high resolution XPS spectra indicate that N element has been doped in the lattice of ZrO₂. Visible-light photocatalytic reactions using the N-doped ZrO₂ photocatalysts (i.e. ZON, AZON) calcined at 450 °C show the highest hydrogen production rate (2.12 mmol g⁻¹ h⁻¹) and best methylene orange degradation performance due to substitutional N-doping of the ZrO₂. The novel N-doped ZrO₂ materials are demonstrated to be very promising photocatalysts with enhanced visible-light photocatalytic activity. Our results provide useful insights into the development of novel photocatalytic materials for hydrogen production and degradation of organic wastes by narrowing the wide bandgap of semiconductors with high photocatalytic activity under UV-Vis light.

Two new types of N-doped ZrO₂ photocatalysts ZON and AZON have been synthesized using ethylenediamine as the nitrogen source by a facile and low-cost sol–gel method.     

Electrochemical oxidizing digestion using PbO2 electrode for total phosphorus determination in a water sample

Total phosphorus is one of the key water quality parameters in environmental monitoring. To precisely determine the total phosphorus, water samples have to be pretreated to convert the various forms of phosphorus to orthophosphate. Conventionally, pretreatment is accomplished by heating, acidification, and oxidation in a digestion equipment, which is dangerous, time-consuming, and complicated. Herein, we propose a novel high-performance electrochemical oxidation protocol for phosphorus digestion based on a PbO₂ electrode. The electrode, which has a hydrophobic and stable surface, was prepared by electrochemical deposition on a titanium substrate and has high hydroxyl radical utilization when digesting total phosphorus. As a result, 90% of sodium glycerophosphate was digested within 30 minutes, and high digestion ratios of acephate, glyphosate, and inland water samples were obtained as well. In addition, this electrochemical digestion protocol does not required heating and acidification steps, which shortens the digestion time. Therefore, a rapid quantification of total phosphorus in the water sample was achieved.

Using electrochemical oxidation for digestion when testing total phosphorus with a digestion ratio of about 90%.     

Fabrication and photocatalytic property of magnetic SrTiO3/NiFe2O4 heterojunction nanocomposites

Novel multifunctional SrTiO₃/NiFe₂O₄ nanocomposites were successfully fabricated via a two-step route. The as-prepared samples were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), field-emission transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the SrTiO₃/NiFe₂O₄ heterostructures are composed of SrTiO₃ spheroidal nanoparticles adhered to NiFe₂O₄ polyhedra. The heterojunction established in the composite material accelerates the process of electron–hole pair separation and boosts the photo-Fenton reaction. Among the samples, 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites exhibit a powerful light response and excellent room temperature ferromagnetism. Subsequently, the photocatalytic degradation of RhB over the as-prepared samples was investigated and optimized, revealing that the 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites exhibit the best photocatalytic activity and stability under simulated solar light irradiation. Furthermore, according to experimental results, the possible mechanism of improved photocatalytic activity was also proposed.

Photocatalytic degradation of RhB for all samples under simulated solar light illumination and absorption spectra of RhB over 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites.     

Glucose monitoring in living cells with single fluorescent protein-based sensors

Glucose is the main source of energy and carbon in organisms and plays a central role in metabolism and cellular homeostasis. However, the sensitive fluctuation of glucose in living cells is difficult to monitor. Thus, we developed a series of ratiometric, highly responsive, single fluorescent protein-based glucose sensors of wide dynamic range by combining a circularly permuted yellow fluorescent protein with a bacterial periplasmic glucose/galactose-binding protein. We used these sensors to monitor glucose transport in living Escherichia coli cells, and found that the cells take up glucose within 10 min to maintain physiological glucose levels, and observed the differences in glucose uptake and glucose metabolism between wild-type and Mlc knockout cells. These sensors can be specific and simple tools for glucose detection in vitro and non-invasive tools for real-time monitoring of glucose metabolism in vivo.

Glucose is the main source of energy and carbon in organisms and plays a central role in metabolism and cellular homeostasis.     

High and low molecular weight hyaluronic acid-coated gold nanobipyramids for photothermal therapy

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. It is known that hyaluronic acid (HA) binds CD44 receptors, which are overexpressed on the surface of TNBC cells. To optimize the targeting ability of HA, in this study we coated gold nanobipyramids (GBPs) with high and low molecular weight HA (380 kDa and 102 kDa), named GBPs@h-HA and GBPs@l-HA, respectively. GBPs@l-HA and GBPs@h-HA had excellent stability when dispersed in water and PBS (pH 7.4) for seven days. The HA density was calculated by the ratio of HA to GBPs@l-HA and GBPs@h-HA, which was 13.22 and 4.77, respectively. The two nanoparticles displayed good photostability, which was evaluated by their photothermal performance and similar biocompatibility. Inductively coupled plasma atomic emission spectrometry (ICP-AES) revealed superior cellular uptake of GBPs@h-HA over GBPs@l-HA. Upon 808 nm laser irradiation, the GBPs@h-HA also showed higher therapeutic efficacy than GBPs@l-HA both in vitro and in vivo. Overall, our study demonstrates that the molecular weight of HA plays an important role in the targeting ability and thus photothermal therapeutic efficacy of HA-coated gold nanobipyramids.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. Hyaluronic acid (HA) could bind CD44 receptors, which are overexpressed on the surface of TNBC cells. Upon 808 nm laser irradiation, the GBPs@HA showed high therapeutic efficacy in vivo.