Three-dimensional porous carbon derived from different organic acid salts for application in electrochemical sensing

Three-dimensional porous carbon materials were synthesized by the one-step pyrolysis of organic salts with different numbers of hydroxyl groups on the side chain (sodium tartrate, sodium malate and sodium succinate). Further, the formation of these porous carbon materials was explored. And then, three kinds of carbon materials were used for constructing electrochemical sensors for nitrite detection, respectively. Porous carbon derived from sodium tartrate (PC_ST) showed the highest electrocatalytic ability for nitrite oxidation among all three materials. The PC_ST-based sensors allow for rapid detection of nitrite in a wide linear range of 0.1–100 μM with a low detection limit of 0.043 μM. The sensor was applied to detect nitrite in meat samples and the results tested by the developed sensor were consistent with the results obtained by HPLC. We envision that PC_ST-based electrochemical sensor is promising as an alternative choice for the development of electrochemical analysis.

Three-dimensional porous carbon materials were synthesized by the one-step pyrolysis of organic salts with different numbers of hydroxyl groups on the side chain (sodium tartrate, sodium malate and sodium succinate).     

New insight into the joint significance of dietary jujube polysaccharides and 6-gingerol in antioxidant and antitumor activities

The combinatorial use of dietary jujube (Ziziphus jujuba) and ginger play a critical role in traditional Chinese medicines, folk medicine and dietary therapy. Joint effects were investigated from the viewpoint of the antioxidant (scavenging DPPH˙) and antitumor activities (against SW620 cells) of jujube polysaccharides and ginger 6-gingerol (G6G) alone and in combination. Jujube polysaccharides were extracted, purified, and characterized, and then their inhibiting and apoptotic effects alone and in combination with G6G were evaluated by the cytological tests, including Cell Counting Kit-8, colony-forming, Annexin V-FITC and propidium iodide, TdT-mediated dUTP nick end labeling (TUNEL) staining, and cell cycle assays. Results showed that the purified polysaccharide fraction (ZJPs-II) with average molecular weight of 115 kDa consisted of arabinose, rhamnose, glucose, xylose, and galactose. ZJPs-II and G6G alone dose-dependently scavenged DPPH˙ and inhibited the proliferation of SW620 cells, while their combination showed synergistic interactions (all combination index < 1). The studies further demonstrated that ZJPs-II and G6G alone reduced the cell colony-formation, induced apoptosis and arrested the cell-cycle at G2/M phase, while their combination achieved better effects and significantly arrested the growth at the G0/G1 phase. Collectively, our findings suggest enhancing the intake of jujube polysaccharides and G6G in a combinatorial approach for maintaining health and preventing cancer.

The combinatorial use of dietary jujube (Ziziphus jujuba) and ginger play a critical role in traditional Chinese medicines, folk medicine and dietary therapy.     

The growth behavior of brain-like SnO2 microspheres under a solvothermal reaction with tetrahydrofuran as a solvent and their gas sensitivity

In this paper, the growth behavior of brain-like SnO₂ microspheres synthesized by a tetrahydrofuran (THF) solvothermal method was studied. Unlike water or ethanol as the solvent, THF is a medium polar and aprotic solvent. Compared with other common polar solvents, the THF has no strong irregular effects on the growth process of SnO₂. In addition, the viscosity of THF also helps the SnO₂ to form a regular microstructure. The growth behavior of the brain-like SnO₂ microspheres is controlled by changing the synthesis temperature of the reaction. The SEM and TEM results reveal that the SnO₂ forms particles first (125 °C/3 h), and then these nanoparticles connect to each other forming nanowires and microspheres (diameter ≈ 1–2 μm) at 135 °C for 3 h; finally the microspheres further aggregate to form double or multi-sphere structures at 180 °C for 3 h. In this paper, the brain-like SnO₂ microspheres obtained at 125 °C for 3 h were selected as sensitive materials to test their gas sensing performance at different operating temperature (50 °C and 350 °C). The H₂S was tested at 50 °C which is the lowest operating temperature for the sensor. The combustible gas (H₂/CH₄/CO) was measured at 350 °C which is the highest temperature for the sensor. They all have extremely high sensitivity, but only H₂S has excellent selectivity.

A highly-sensitive MEMS sensor is fabricated based on brain-like SnO₂ microspheres under a solvothermal reaction with tetrahydrofuran as a solvent.     

Near-infrared tunable surface plasmon resonance sensors based on graphene plasmons via electrostatic gating control

A tunable near-infrared surface plasmon resonance sensor based on graphene plasmons via electrostatic gating control is investigated theoretically. Instead of the traditional refractive index sensing, the sensor can respond sensitively to the change of the chemical potential in graphene caused by the attachment of the analyte molecules. This feature can be potentially used for biological sensing with high sensitivity and high specificity. Theoretical calculations show that the chemical potential sensing sensitivities under wavelength interrogation patterns are 1.5, 2.21, 3, 3.79, 4.64 nm meV⁻¹ at different wavebands with centre wavelengths of 1100, 1310, 1550, 1700, 1900 nm respectively, and the full width half maximum (FWHM) is also evaluated to be 10, 25.5, 43, 55.5, 77 nm at these different wavebands respectively. It can be estimated that the theoretical limit of detection (LOD) in DNA sensing of the proposed sensor can reach the femtomolar level, several orders of magnitude superior to that of noble metal-based SPR sensors (nanomolar or subnanomolar scale), and is comparable to that of noble metal-based SPR sensors with graphene/Au-NPs as a sensitivity enhancement strategy. The FWHM is much smaller than that of the noble metal-based SPR sensors, making the proposed sensor have a potentially higher figure of merit (FOM). This work provides a new way of thinking to detect in an SPR manner the analyte that can cause chemical potential change in graphene and provides a beneficial complement to refractive index sensing SPR sensors.

A tunable near-infrared surface plasmon resonance sensor based on graphene plasmons via electrostatic gating control is investigated theoretically.     

Rapid large-scale synthesis of ultrathin NiFe-layered double hydroxide nanosheets with tunable structures as robust oxygen evolution electrocatalysts

Transition metal layered double hydroxides (LDHs) with ultrathin two-dimensional (2D) structures, especially NiFe-based LDH nanosheets, have been extensively developed as advanced oxygen evolution reaction (OER) electrocatalysts for water splitting. Nevertheless, traditional synthetic approaches for these promising catalysts usually involve tedious pretreatment procedures and a subsequent time-consuming exfoliation process, and the obtained products possess a wide dispersion of thickness and limited production yield. Here, a sequence of ultrathin NiFe-LDH nanosheets with tunable components were prepared on a large scale via a rapid room-temperature method under ambient conditions, and were further used as a desired material model for studying the influence of Ni/Fe ratio modulation on the OER performance. Due to the synergetic effect of more exposed active sites, efficient electron transport and optimized OER kinetics, the resulting LDH samples manifest outstanding electrocatalytic performance toward water oxidation.

A sequence of ultrathin NiFe-LDH nanosheets with tunable components were prepared via a rapid room-temperature method, which were further used as efficient electrocatalysts for water oxidation.     

Qualitative and quantitative adsorption mechanisms of zinc ions from aqueous solutions onto dead carp derived biochar

The objective of this study is to investigate the qualitative mechanisms of Zn²⁺ adsorption on carp biochars (CMBx) produced from dead carp at different temperatures (450–650 °C) and their quantitative contribution. The pseudo second order kinetic model and the Langmuir model could fit the kinetic and isothermal adsorption data well, respectively. The intra-particle diffusion was the main rate-limiting step but not the only rate-limiting step. The maximum adsorption capacity obtained from the Langmuir model for CMB650 was 87.7 mg g⁻¹ which was greater than those of other biochars. Precipitation with minerals, ion exchange, and complexation with functional groups (OFGs) were the main adsorption mechanisms. Quantum chemistry calculations confirmed that the functional groups (e.g., hydroxyl, carboxyl and C C) tended to bind with Zn²⁺ more strongly than with Ca²⁺ and Mg²⁺, because the structure of the complex formed by the former was more stable. The contribution of different adsorption mechanisms varied with the pyrolysis temperature to prepare biochar. With increasing pyrolysis temperature, the contribution of the interaction between Zn²⁺ and the minerals increased from 46.4% to 84.7%, while that of complexation with OFGs decreased from 41.7% to 4.7%. Overall, the mechanism of Zn²⁺ adsorption on CMB450 was dominated by complexation with OFGs and exchange with cations (accounting for 73.2%), while the mechanisms on CMB650 were dominated by the interaction with minerals. In view of the total adsorption capacity, 650 °C was the optimized pyrolysis temperature for CMBx preparation and adsorption treatment of Zn-contaminated water. These results are useful for screening effective biochars as engineered sorbents to treat Zn-containing wastewater.

The adsorption mechanisms of Zn²⁺ on carp biochars mainly include precipitation with minerals, exchange with cations, and complexation with OFGs. The pyrolysis temperature of carp biochars has a significant effect on the mechanisms of Zn²⁺ adsorption.     

Multifunctional sensors based on liquid crystals scaffolded in nematic polymer networks

Stimuli-responsive liquid crystal (LC) materials have attracted great attention due to their unique characteristics and anisotropic properties. They are not only important for fundamental studies, but also have many potential applications in the electro-optical and biochemical fields. Herein, the interference color obtained from a nematic polymer network-stabilized liquid crystal (PNLC) system is demonstrated to reflect the environmental conditions, including temperature and the presence of volatile organic vapors. The polymerization of LC monomers forms a stable network to template the LCs, while still maintaining the dynamic nature and thermal tunability of LCs. Via adjusting the concentration of LC monomer, a wide temperature sensing range can be achieved between 36 °C and 100 °C with visible color. The same sensor can be used to detect concentration profiles of toluene vapor in a microchannel with a limit of detection of 2300 ppm. This stimuli-responsive PNLC system is expected to be potentially useful for many other naked-eye sensing applications.

Naked-eye color change as a result of temperature change or VOC exposure was demonstrated in a nematic polymer network-stabilized liquid crystal (PNLC) system.     

PbI2 3D network transporting model for the charge separation mechanism of PbSe detectors

PbSe films deposited by chemical bath deposition (CBD) technology were sensitized in various atmospheres to distinguish the role of iodine and oxygen in the sensitization process. No infrared (IR) photo response was observed in samples sensitized in pure oxygen, showing the O element cannot trigger the infrared response of PbSe. However, a high detectivity of 1 × 10¹⁰ was achieved in the sample sensitized in a N₂/I₂ atmosphere, which demonstrates iodine is a key element for inducing an IR response. The role of iodine was analyzed from the morphological evolution, phase composition transformation and resistance change during the sensitization process. The XRD and FESEM results show a PbI₂ 3D network forming around the PbSe grains in the sensitization process, playing the role of photo-generated electron transporting channels, which is key to inducing the IR response of PbSe detectors. The 3D network conducting model can explain well the charge separation mechanism of PbSe IR photoconductive detection.

As the transporting channels for the photogenerated electrons, the integrity and densification of the PbI₂ 3D network structure distributed in the interfaces between PbSe crystalline grains dominates the performances of PbSe detectors.     

Medline(PubMed)免疫学杂志文献搜索引擎开发研究

为了方便免疫学和相关学科工作者方便快捷、准确地查阅免疫学杂志文献,开发和利用NCBI的Medline数据库的免疫学杂志文献资源。从Medline(PubMed)中检索并列出160种有关免疫学的杂志名录,制作了每种杂志及部分杂志年份相应的超级链接,组成一个有关免疫学杂志文献的搜索引擎。此搜索引擎能快捷、准确、动态地检索160种免疫学杂志全部文献题录及部分杂志各年的文献题录,并可在PubMed中进一步检索出文献的摘要和部分全文。     

Phospho-Aspirin (MDC-22) inhibits pancreatic cancer growth in patient-derived tumor xenografts and KPC mice by targeting EGFR: Enhanced efficacy in combination with irinotecan

Novel therapeutic strategies are needed in the fight against pancreatic cancer. We have previously documented the chemopreventive effect of MDC-22 in preclinical models of pancreatic cancer. In the present work, we examined the therapeutic effects of MDC-22 in patient-derived tumor xenografts (PDTXs) and in LSL-Kras^G12D/+, LSL-Trp53^R172H/+, Pdx1-Cre (KPC) genetically engineered mice, two complementary and clinically relevant animal models of pancreatic cancer. In addition, we evaluated whether MDC-22 could synergize with current chemotherapeutic drugs used in the clinic. MDC-22 reduced the growth of various human pancreatic cancer cell lines in a concentration-dependent manner. In vivo, MDC-22 strongly reduced patient-derived pancreatic tumor xenograft growth by 50%, and extended survival of LSL-Kras^G12D/+; LSL-Trp53^R172H/+; Pdx1-Cre (KPC) mice by over a month (5.3 months versus 7.0 months). In both models, MDC-22 inhibited EGFR activation and its downstream signals, including ERK and FAK phosphorylation. In human pancreatic cancer cell lines, MDC-22 enhanced the growth inhibitory effect of irinotecan, and to a lesser degree those of gemcitabine and nab-paclitaxel. Normal human pancreatic epithelial cells were more resistant to the cytotoxic effects of, both, MDC-22 alone or in combination with irinotecan, indicating selectivity. Furthermore, MDC-22 enhanced irinotecan''s effect on cell migration, in part, by inhibiting EGFR/FAK signaling. Collectively, our results indicate that MDC-22 is an effective anticancer drug in preclinical models of pancreatic cancer, and suggest that MDC-22 plus irinotecan as drug combination strategy for pancreatic cancer treatment, which warrants further evaluation.