Differential Evolution Particle Swarm Optimization for Phase-Sensitivity Enhancement of Surface Plasmon Resonance Gas Sensor Based on MXene and Blue Phosphorene/Transition Metal Dichalcogenide Hybrid Structure.

A differential evolution particle swarm optimization (DEPSO) is presented for the design of a high-phase-sensitivity surface plasmon resonance (SPR) gas sensor. The gas sensor is based on a bilayer metal film with a hybrid structure of blue phosphorene (BlueP)/transition metal dichalcogenides (TMDCs) and MXene. Initially, a Ag-BlueP/TMDCs-Ag-MXene heterostructure is designed, and its performance is compared with that of the conventional layer-by-layer method and particle swarm optimization (PSO). The results indicate that optimizing the thickness of the layers in the gas sensor promotes phase sensitivity. Specifically, the phase sensitivity of the DEPSO is significantly higher than that of the PSO and the conventional method, while maintaining a lower reflectivity. The maximum phase sensitivity achieved is 1.866 × 106 deg/RIU with three layers of BlueP/WS2 and a monolayer of MXene. The distribution of the electric field is also illustrated, demonstrating that the optimized configuration allows for better detection of various gases. Due to its highly sensitive characteristics, the proposed design method based on the DEPSO can be applied to SPR gas sensors for environmental monitoring.

Tunable oligo-histidine self-assembled monolayer junction and charge transport by a pH modulated assembly.

Histidine works as an important mediator in the charge transport process through proteins via its conjugate side group. It can also stabilize a peptide's secondary structure through hydrogen bonding of the imidazole group. In this study, the conformation of the self-assembled monolayer (SAM) and the charge transport of the tailor-made oligopeptide hepta-histidine derivative (7-His) were modulated through the pH control of the assembly environment. Histidine is found to be an efficient tunneling mediator in monolayer junctions with an attenuation factor of ß = ∼0.5 Å-1. Successful theoretical model fitting indicates a linear increase in the number of tunneling sites as the 7-His SAM thickness increases, following the deprotonation of histidine. Combined with the ultraviolet photoelectron spectroscopy (UPS) measurements, a modulable charge transport pathway through 7-His with imidazole groups of histidine as tunneling foot stones is revealed. Histidine therefore possesses a large potential for modulable functional (bio)electronic devices.

Sensitivity enhancement of an SPR biosensor with a graphene and blue phosphorene/transition metal dichalcogenides hybrid nanostructure.

A novel surface plasmon resonance (SPR) biosensor based on Ag-Au bimetallic films with a hybrid structure of blue phosphorene (BlueP)/transition metal dichalcogenides (TMDCs) and graphene is presented. In order to improve the sensitivity, the thickness of silver and gold films is optimized to achieve minimum reflectivity and an adequate level of sensitivity; further, sensitivity for the monolayer BlueP/MoS2 and graphene structure is enhanced by 19.73%, with respect to a traditional sensor. Besides, the effect of layers of different Blue/TMDCs heterostructures to the sensitivity of the SPR biosensor is investigated, and the highest sensitivity with 335.4°/RIU for the bilayer BlueP/WS2 is obtained. Furthermore, distributions of the electric field and the changes of resonance angle to the refractive index of the sensing medium and prism in the visible regime are illustrated at optimal configuration. In virtue of highly sensitive characteristics, the proposed sensor structure will be a much better option to be employed for further biological detection.

An Improved Seeker Optimization Algorithm for Phase Sensitivity Enhancement of a Franckeite- and WS2-Based SPR Biosensor for Waterborne Bacteria Detection.

For the purpose of detecting waterborne bacteria, a high-phase-sensitivity SPR sensor with an Ag-TiO2-Franckeite-WS2 hybrid structure is designed using an improved seeker optimization algorithm (ISOA). By optimizing each layer of sensor construction simultaneously, the ISOA guarantees a minimum reflectance of less than 0.01 by Ag (20.36 nm)-TiO2 (6.08 nm)-Franckeite (monolayer)-WS2 (bilayer) after 30 iterations for E. coli. And the optimal phase sensitivity is 2.378 × 106 deg/RIU. Sensor performance and computing efficiency have been greatly enhanced using the ISOA in comparison to the traditional layer-by-layer technique and the SOA method. This will enable sensors to detect a wider range of bacteria with more efficacy. As a result, the ISOA-based design idea could provide SPR biosensors with new applications in environmental monitoring.

Effects of Ultrasonic Treatment on Physical Stability of Lily Juice: Rheological Behavior, Particle Size, and Microstructure.

The aim of this study was to investigate the rheological properties, particle size distribution, color change, and stability of lily juice under different ultrasonic treatment conditions (152 W, 304 W, 456 W, 608 W, and 760 W). The results showed that the lily juice exhibited non-Newtonian shear thinning behavior, and the viscosity decreased with the increase in ultrasonic power. Under ultrasonic treatment conditions, there was no significant change in the pH value and zeta potential value of the samples. The content of cloudy value and total soluble solids (TSS) increased gradually. However, both the sedimentation components and centrifugal sedimentation rate showed a downward trend and an asymptotic behavior. In addition, high-power ultrasound changed the color index (L* value decreased, a* value increased), tissue structure, and particle distribution of the sample, and small particles increased significantly. To sum up, ultrasonic treatment has great potential in improving the physical properties and suspension stability of lily juice.

Functional characterization of IL-18 receptor subunits, IL-18Rα and IL-18Rß, and its natural inhibitor, IL-18 binding protein (IL-18BP) in rainbow trout Oncorhynchus mykiss.

As an important proinflammation and immunomodulatory cytokine, IL-18 has been reported in several species of fish, but its receptor subunits, IL-18Rα and IL-18Rß, and its decoy receptor, IL-18BP, have not been functionally characterized in fish. In the present study, IL-18Rα, IL-18Rß and IL-18BP were cloned from rainbow trout Oncorhynchus mykiss, and they possess common conserved domains with their mammalian orthologues. In tested organs/tissues, IL-18Rα and IL-18Rß exhibit basal expression levels, and IL-18BP has a pattern of constitutive expression. When transfected with different combinations of chimeric receptors in HEK293T cells, recombinant IL-18 (rIL-18) can induce the activation of NF-κB only when pcDNA3.1-IL-18Rα/IL-1R1 and pcDNA3.1-IL-18Rß/IL-1RAP were both expressed. On the other hand, recombinant receptors, including rIL-18BP, rIL-18Rα-ECD-Fc and rIL-18Rß-ECD-Fc can down-regulate significantly the activity of NF-κB, suggesting the participation of IL-18Rα, IL-18Rß and IL-18BP in rainbow trout IL-18 signal transduction. Co-IP assays indicated that IL-18Rß may form a complex with MyD88, IRAK4, IRAK1, TRAF6 and TAB2 in HEK293T cells, indicating that IL-18Rß, in IL-18 signalling pathway, is associated with these signalling molecules. In conclusion, IL-18Rα, IL-18Rß and IL-18BP in rainbow trout are conserved in function and signalling pathway with their mammalian orthologues.

Nanoscale film thickness measurement based on weak measurement.

In this paper, a novel method of film thickness measurement based on weak measurements is proposed by analyzing the quantitative relationship between film thickness and the weak measurement amplified shift of the photonic spin Hall effect, and the corresponding measurement system is established to verify it through experiments. This method can measure the thickness of an arbitrary dielectric film with nanometer resolution. The theoretical analysis and experimental results show that the method is reasonable, feasible, and reliable, and the structure of the measurement system is simple, easy to operate, and easy to assemble into a prototype instrument. The measurement model and method provide not only a new way for the measurement of thin film thickness but also an important reference for the precise measurement of other optical interface parameters.

Saikosaponin A protects against dextran sulfate sodium-induced colitis in mice.

Ulcerative colitis, one of the most important inflammatory bowel diseases, affects millions of people worldwide. The aim of this study was to investigate the effects of Saikosaponin A on dextran sulfate sodium (DSS)-induced colitis in mice. The mice were treated with 2.5% DSS for 5 d to induce acute colitis. Saikosaponin A was given 3 d before and during DSS treatment by intragastric administration. The results showed that Saikosaponin A significantly inhibited DSS-induced body weight loss and shortening of colon length. DSS-induced colonic histological changes and MPO activity were also prevented by treatment of Saikosaponin A. The levels of TNF-α and IL-1ß were increased by DSS and dose-dependently inhibited by Saikosaponin A. Furthermore, Saikosaponin A significantly inhibited DSS-induced NF-κB activation and up-regulated the expression of LXRα. Taken together, our results indicated that Saikosaponin A had protective effects against DSS-induced colitis. Saikosaponin A protected DSS-induced colitis through inhibiting inflammatory response.

Comparative experiments of fibril formation from whey protein concentrate with homogeneous and secondary nuclei.

Two types of special structures, homogeneous and secondary nuclei, form during fibril formation. The structural and functional properties of amyloid fibrils in whey protein concentrate (WPC) with different ratios of added homogeneous nuclei to secondary nuclei were investigated. Thioflavin T fluorescence analysis and kinetic equations indicated that two types of nuclei could accelerate WPC fibrillation compared with WPC self-assembling into amyloid fibrils, thereby reducing the lag time and increasing the number of fibrils. However, there were considerable differences in the nucleation-inducing capability of WPC fibrillation between homogeneous and secondary nuclei. The number of fibrils formed by adding homogeneous nuclei was higher than that obtained with secondary nuclei, the increase in the Th T fluorescence intensity induced by homogeneous nuclei was 1.83-fold much than secondary nuclei. Meanwhile, secondary nuclei yielded a 2.71-fold faster aggregation rate of WPC than homogeneous nuclei, particularly during the first hour of thermal treatment (protein mass ratio of nuclei to WPC 1:1). The gelation time of WPC after secondary nuclei addition was shorter, from 10 h (WPC (2.0/6.5)) to 4 h (WPC + HN) to 2 h (WPC + SN); however, the gel microstructure of WPC after the addition of homogeneous nuclei was denser, yielding a preferred water holding capacity.

Insights into the chemical characterization and sources of PM(2.5) in Beijing at a 1-h time resolution.

As the widespread application of online instruments penetrates the environmental fields, it is interesting to investigate the sources of fine particulate matter (PM2.5) based on the data monitored by online instruments. In this study, online analyzers with 1-h time resolution were employed to observe PM2.5 composition data, including carbon components, inorganic ions, heavy metals and gas pollutants, during a summer in Beijing. Chemical characteristics, temporal patterns and sources of PM2.5 are discussed. On the basis of hourly data, the mean concentration value of PM2.5 was 62.16±39.37 µg m(-3) (ranging from 6.69 to 183.67 µg m(-3)). The average concentrations of NO3(-), SO4(2-), NH4(+), OC and EC, the major chemical species, were 15.18±13.12, 14.80±14.53, 8.90±9.51, 9.32±4.16 and 3.08±1.43 µg m(-3), respectively. The concentration of PM2.5 varied during the online-sampling period, initially increasing and then subsequently decreasing. Three factor analysis models, including principal component analysis (PCA), positive matrix factorization (PMF) and Multilinear Engine 2 (ME2), were applied to apportion the PM2.5 sources. Source apportionment results obtained by the three different models were in agreement. Four sources were identified in Beijing during the sampling campaign, including secondary sources (38-39%), crustal dust (17-22%), vehicle exhaust (25-28%) and coal combustion (15-16%). Similar source profiles and contributions of PM2.5 were derived from ME2 and PMF, indicating the results of the two models are reasonable. The finding provides information that could be exploited for regular air control strategies.