3D Porous Graphene Architecture Integrated with Cu2O for Enhanced Electrochemical Sensing Performance.

Construction and functionalization of a 3D graphene architecture are crucial to harness and extend the unique features of graphene and thus essential for its numerous conventional and novel applications. Herein, a 3D honeycomb-patterned porous graphene architecture is constructed through a facile and low-cost self-assembly process and then integrated with Cu2O nanoparticles via a simple electrodeposition procedure. The 3D porous graphene structure is prepared by the breath figure method using a graphene oxide (GO)-based complex in which GO is modified by a surfactant as the casting material. Benefiting from the intercalation of the surfactant between the GO nanosheets and the fabrication of a 3D porous structure, the aggregation inhibition of GO nanosheets and increases in accessible surface area are realized at both nano- and microscales, resulting in good electrochemical performance. Moreover, the deposition of Cu2O nanoparticles can further improve the electrochemical sensing performance of the porous reduced graphene oxide (rGO) structure. Extremely low detection limit (30.72 nM) with a linear range of 0 µM to 30 µM, excellent anti-interference, repeatability, reproducibility, stability, and high accuracy for actual sample testing are shown when the 3D porous Cu2O/rGO film is applied as an electrochemical sensor for DA detection. This work provides not only a superior electrochemical biosensor but also a simple, yet effective and general strategy for the construction and functionalization of a 3D graphene structure.

Suitability evaluation and potential estimation of photovoltaic power generation and carbon emission reduction in the Qinghai-Tibet Plateau.

The expansion of power development industry is facing enormous pressure to reduce carbon emissions in the context of global decarbonization. Using solar energy instead of traditional fossil energy to adjust energy structure is one of the important means for reducing carbon emissions. Existing research focuses on the evaluation of the generation potential of centralized or distributed photovoltaic power plants, rather than the comprehensive evaluation of multi-type power plants. Based on multi-source remote sensing data for information extraction and suitability evaluation, this paper develops a method to comprehensively evaluate the construction potential of multi-type photovoltaic power stations and determine the potential of photovoltaic power generation and carbon emission reduction on the Qinghai-Tibet Plateau (QTP). The results showed that estimating the power generation potential of only single-type photovoltaic power stations cannot accurately reflect the photovoltaic power generation potential of QTP. It is also demonstrated that the emission reduction effect of the photovoltaic power generation in all prefecture-level cities of QTP can meet national emission reduction targets, showing high annual power generation potential, of which 86.59% is concentrated in Qinghai province's Guoluo, Yushu, and Haixi. An accurate estimation of the photovoltaic power generation potential in QTP can provide a useful theoretical basis for developing carbon-saving and emission reduction strategies for clean energy in China.

Overall Improvement in Dielectric, Water Resistance and Mechanical Properties of Polyimide Film via Synergy between GO and Sandwich-type Porous Structure.

Simultaneous improvement in dielectric, water resistance and mechanical properties of polyimide (PI) films is critical for their practical use, but difficult to achieve. Herein, a sandwich-type porous GO/PI film with excellent comprehensive properties was obtained through integrating a GO-containing complex, fluorine-containing porous structure and sandwich-type distribution of porous structure by a simple, low-cost and green breath figure method. With the addition of only a small amount of GO-containing complex, a low dielectric constant of 2.21, water absorption of 0.51%, increment in dielectric constant after moisture treatment of 1.60% and high tensile strength of 113.1 MPa, tensile modulus of 1.70 GPa, with 35.39%, 79.42%, 81.81% of reduction and 17.22%, 21.43% of increase compared to PI film were shown, respectively. Moreover, these properties could be adjusted through regulating the component and porous structure by changing the parameters of breath figure method. These outstanding properties make the film a promising candidate for high-performance low-dielectric materials.

Competition among cities for export trade brings diversification: The experience of China's urban export trade development.

Market competition is considered to have a significant impact on product diversification, but related issues are rarely discussed on a city scale. To analyze the diversification of export commodities and export market of 270 Chinese cities, this study uses data from 2000 to 2017 based on the commodity concentration index, market concentration index, export similarity index, spatial stratified heterogeneity, and the Almon lag model. The study's findings are: (1) The diversification of exports in most Chinese cities increased, which was higher in more developed cities in the southeast than in less developed ones in the northwest. With time, the degree of commodity and market diversification in some developed southeast Chinese cities (e.g., Shanghai) declined. This indicates the difference in and complexity of the evolution of export development in hundreds of Chinese cities between 2000 and 2017. (2) The export competition between cities became increasingly fierce, which effectively urged most of them to improve their export diversification levels. Facing increasing export competition pressure, 81.11% of the total number of cities will enhance the diversification of export commodities to cope with challenges posed by other cities. But only 56.67% will further expand the export market when the pressure of export competition increases. The biggest contribution of this study is the finding that for most Chinese cities, when export competition from other domestic cities increases, increasing diversification of products becomes a wise choice. However, the influence of competition on the diversification degree of the city's export market is relatively weak. This study provides not only a new perspective for existing research on urban export trade, but also valuable information for cities to form a more profitable and robust trading system.

ß-Elemene alleviates cisplatin resistance in oral squamous cell carcinoma cell via inhibiting JAK2/STAT3 pathway in vitro and in vivo.

OBJECTIVE: To investigate the effect of ß-Elemene (ß-Ele) on the cisplatin sensitivity of OSCC cells and its mechanism in vitro and in vivo. METHODS: The human OSCC cell lines Tca-8113 and the cisplatin-resistant cell line Tca-8113-CDDP were cultured with ß-Ele or/and cisplatin. The cytotoxicity of cisplatin or ß-Ele, cell viability, cell cycles and apoptosis were detected. And the expression of JAK2/STAT3 related protein were detected. The xenograft tumor model of OSCC was established in nude mice and treated with cisplatin and/or ß-Ele. The volume and weight of the transplanted tumor was measured, and the expression of p-JAK2 and p-STAT3 and cell apoptosis in the xenograft tumor tissues were detected. RESULTS: The combination of ß-Ele and cisplatin significantly suppressed the cell proliferation, induced cell cycle arrest, promoted the apoptosis of Tca-8113-CDDP cells, and suppressed the activation of JAK2/STAT3 signaling pathway. The rescue experiments suggested that ß-Ele enhanced cisplatin sensitivity via down-regulating JAK2/STAT3 signaling pathway. In vivo, ß-Ele and cisplatin synergistically suppressed the tumor growth and induced apoptosis, and down-regulated the expression of p-JAK2 and p-STAT3. CONCLUSIONS: ß-Ele inhibits the cell viability and enhances the cisplatin sensitivity of OSCC by blocking the activation of JAK/STAT3 signaling pathway in vitro and in vivo, and the combination of ß-Ele and cisplatin maybe a novel treatment for OSCC.

Clinical significance of Annexin A2 expression in oral squamous cell carcinoma and its influence on cell proliferation, migration and invasion.

Oral squamous cell carcinoma (OSCC) is the most common malignant epithelial neoplasm of the head and neck, with poorer prognosis. There is lack of specific targets for diagnosis and treatment of OSCC at present. Annexin A2 (ANXA2) is involved in cell angiogenesis, invasion, proliferation and metastasis. In this study, the significance and effect of ANXA2 on OSCC and OSCC cells were explored from the clinical and basic study. First, ANXA2 expression in OSCC tissues and adjacent non-cancer tissues of 124 patients were detected, and the correlation between ANXA2 expression and clinical parameters were analyzed. The results found that ANXA2 was highly expressed in OSCC tissues, and was associated with the TNM stage, tumor differentiation, lymph node metastasis and poor survival of OSCC patients. The expression of ANXA2 in OSCC cells were higher than the normal oral cells. And knockdown of ANXA2 by transfecting ANXA2-siRNA could suppress the proliferation, migration, and invasion abilities of OSCC cells. Overall, ANXA2 expression is correlated with poor survival of OSCC patients, and silencing of ANXA2 suppress the proliferation, migration and invasion of OSCC cells.

Recognition at chiral interfaces: From molecules to cells.

As a ubiquitous phenomenon in nature, chirality plays a pivotal role in a variety of biological and physiological processes. The construction of chiral interfaces and exploration of their effect on the behavior of various substances, especially biomolecules such as DNA, proteins and cells, are effective ways to fully understand the chirality in nature and to further develop their applications. In order to accelerate the research process of chiral mechanism and provide new ideas for the interpretation of chiral phenomena in nature, thus further promoting the applications of chiral effect in biology, medicine and other related fields, various types of chiral interfaces were prepared and their effects on drug molecules, biomolecules and cells have also been investigated. This review covers the preparation of various chiral interfaces with different geometrical structures and the stereoselective interaction between biological or related systems and the chiral interface materials. Moreover, some challenges and perspectives are also presented.

Cell adhesion and proliferation in chiral pores triggered by polyoxometalates.

Chiral polyoxometalates (POMs) were deposited onto the inner surface of an ordered cavernous film to construct POM-based chiral interfaces, which exhibit a significantly different chiral influence on the adhesion and proliferation of Escherichia coli (E. coli) cells tuned by protein adsorption. Anti-fouling was also shown for the racemic surface.

Honeycomb-Patterned Polyimide Film as a Versatile Coating for High-Performance Dielectric Material.

A honeycomb-patterned porous film was conveniently prepared by means of the microemulsion method and then used as an effective coating for improving the dielectric properties and water resistance of polyimide (PI) film while maintaining its mechanical properties. The dielectric properties could be regulated by tuning the structure of the porous film through controlling its formation conditions. When suitable conditions were used, the prepared composite PI film exhibited a significant reduction of 28.3 % in its dielectric constant and 9.48-54.99 % in dielectric loss accompanied by an extremely low water uptake of 0.62 % relative to the 2.47 % of flat PI film. The composite PI film also displayed excellent durability under moist conditions, as the dielectric constant was still below 2.4 after exposure to 75 % relative humidity for more than 12 h. This provides a novel method to improve and control the dielectric properties of materials. It also suggests that this film is a suitable candidate for coating dielectric materials in high-humidity environments.

Research on High Layer Thickness Fabricated of 316L by Selective Laser Melting.

Selective laser melting (SLM) is a potential additive manufacturing (AM) technology. However, the application of SLM was confined due to low efficiency. To improve efficiency, SLM fabrication with a high layer thickness and fine powder was systematically researched, and the void areas and hollow powders can be reduced by using fine powder. Single-track experiments were used to narrow down process parameter windows. Multi-layer fabrication relative density can be reached 99.99% at the exposure time-point distance-hatch space of 120 µs-40 µm-240 µm. Also, the building rate can be up to 12 mm³/s, which is about 3-10 times higher than the previous studies. Three typical defects were found by studying deeply, including the un-melted defect between the molten pools, the micro-pore defect within the molten pool, and the irregular distribution of the splashing phenomenon. Moreover, the microstructure is mostly equiaxed crystals and a small amount of columnar crystals. The averages of ultimate tensile strength, yield strength, and elongation are 625 MPa, 525 MPa, and 39.9%, respectively. As exposure time increased from 80 µs to 200 µs, the grain size is gradually grown up from 0.98 µm to 2.23 µm, the grain aspect ratio is close to 1, and the tensile properties are shown as a downward trend. The tensile properties of high layer thickness fabricated are not significantly different than those with a coarse-powder layer thickness of low in previous research.

A patterned porous polymer film for localized capture of insulin and glucose-responsive release.

A glucose-responsive, porous polymer film which can be used for controlled insulin release was fabricated. By mixing a polystyrene-dichloromethane solution containing didodecylamine with water, with thorough shaking, a reverse microemulsion was achieved. After spreading the microemulsion on a glass slide and evaporating the solvent, an ordered honeycomb-patterned film was produced, accompanied by an accumulation of didodecylamine within the inner surface of the cavities. The patterned cavities were further modified with poly(acrylic acid), 3-aminophenylboronic acid, and alginate so that they would entrap insulin aggregates. The insulin aggregates were prepared using a salting-out method and were incorporated into the cavities by an electrostatic interaction with the alginate. Under the stimulus of glucose, insulin aggregates were released from the cavities and further calculations demonstrated that there was a very high efficiency of release. In contrast, in an aqueous solution without glucose, almost no insulin was released from the cavities. This investigation demonstrates that it is feasible for porous polymer films, whose cavities act as a protein reservoir, to be used as a glucose-responsive insulin delivery vehicle, which may have potential as a controlled-release drug-delivery system for the treatment of diabetes.

Selective adhesion and controlled activity of yeast cells on honeycomb-patterned polymer films via a microemulsion approach.

Selective adhesion, growth promotion, proliferation inhibition and in situ transformation of Saccharomyces cerevisiae cells have been realized in a limited space of honeycomb-patterned polystyrene films prepared through a microemulsion method.

Polyanion cluster patterning on polymer surface through microemulsion approach for selective adsorption of proteins.

A facile method to fabricate honeycomb-patterned polymer films bearing cavities that are locally decorated with inorganic component is developed in this study. By mixing poly(methyl methacrylate) dichloromethane solution containing P123 with polyoxometalate (POM) aqueous solution through shaking, a reversed hybrid microemulsion is obtained. The evaporation of solvent in the microemulsion on solid surface yields an ordered porous film accompanied by the accumulation of P123 and POMs on the inner surface of the cavities. The formation of patterned structure is proved to be independent from the type of POMs, but the size of the cavities can be adjusted to some extent by changing the concentration of surfactant and polymer, and the volume ratio of water and dichloromethane in the solution used for casting. The locally anchored POMs can be readily applied for the selective recognition of proteins. BSA and hemoglobin patterns are then fabricated through their electrostatic interactions with POMs. At lower pH, POM pattern could prior recognize hemoglobin from its mixed solution of BSA, generating a characteristic pattern. The reported work creates an efficient way of patterning organically incompatible components, such as water-soluble molecules and nanoparticles, on porous polymer films for the fabrication of multi-functional hybrid surface structures.

[Effects of intracellular osmolality changes on the voltage-gated sodium channels currents of trigeminal ganglion neuron].

OBJECTIVE: To evaluate the biomechanical effects of intracellular changes on the voltage-gated sodium channels (VGSCs) on trigeminal ganglion neuron (TRGN). METHODS: TRGN cells were acutely isolated from the neonatal SD rats. The voltage-dependent currents of the VGSCs on these neurons were elicited and analyzed by whole-cell patch-clamp recordings and the intracellular anisotonicity stimuli was established by adjusting the content of pipette solution. The effects of hypo-(260 mOsm) and hypertonic (350 mOsm) osmolarity on the activation and inactivation kinetics of VGSCs on TRGN were evaluated, compared with the normal intracellular environment. RESULTS: The results demonstrated that intracellular hypotonic stimuli could influence both the activation and inactivation characteristics of VGSCs currents, including the membrane potential at half inactivation (V0.5) of the G-V and inactivation curves had obvious statistics significance (P<0.05) between hypotonicity (260mOsm) and isotonicity (306mOsm). However, only inactivation properties changed under intracellular hypertonic effects, including inactivation rate and k value. CONCLUSION: It suggests that the kinetics of VGSCs on TRGN can be modulated both by intracellular hypo- and hypertonic with different characteristics.

Honeycomb micropatterning of proteins on polymer films through the inverse microemulsion approach.

Here we report the rapid and convenient patterning of proteins on porous polymer film using the inverse microemulsion approach. Following this method, proteins, which were dissolved in water, were transferred into dichloromethane solution of polymers through the formation of inverse microemulsion by mixing the two solutions. The protein-containing microemulsion droplets accumulated automatically into large and stable ones on the surface of organic solution casting on solid substrates, and formed tightly packed microemulsion droplet arrays driven by surface tension. With the evaporation of organic solvent and water, the microemulsion droplet arrays, which act as the template, turn to honeycomb patterned pores bearing proteins in them. The formed protein patterns can be locally applied for the detection of other proteins through specific recognition. The generality and reproducibility for the formation of BSA/PS microporous film and protein patterning by using different polymers and solvents were demonstrated by investigating surfactant addition, polymer and solvent types, and casting volume on the morphology of the microporous films. A preliminary mechanism for the protein patterning is discussed based on the analysis of the experimental results.

A label-free biosensor based on silver nanoparticles array for clinical detection of serum p53 in head and neck squamous cell carcinoma.

By using triangular silver (Ag) nanoparticle array, a localized surface plasmon resonance (LSPR) nanosensor was fabricated and shown to sense serum p53 protein in vitro, which is involved in head and neck squamous cell carcinoma (HNSCC). The nanosensor consists of a triangular Ag nanoparticles array with single particle dimension of 120 nm in-plane width and 45 nm out-of-plane height. When examined using LSPR nanobiosensor, the results indicated significant difference in LSPR shifts (Δλ(max)) between HNSCC patient and control. Although there is need for precise quantification and large-scale prospective, this report shows that the LSPR nanobiosensor provides a promising platform with attractive advantages for serological diagnosis or molecular diagnosis in tumor, such as HNSCC. This is the first clinical application of the LSPR nanosensor in HNSCC.