The determination of nitrate nitrogen (NO₃-N) in recirculating aquaculture systems is of great significance for the health assessment of the living environment of aquatic animals. Unfortunately, the commonly used spectrophotometric methods often yield unstable results, especially when the ambient temperature varies greatly in the field measurement. Here, we have developed a novel handheld absorbance measurement sensor based on the thymol-NO₃-N chromogenic rearrangement reaction. In terms of hardware, the sensor adopts a dual channel/dual wavelength colorimeter structure that features a modulated light source transmitter and a synchronous detector receiver. The circuit measures the ratio of light absorbed by the sample and reference containers at two LEDs with peak wavelengths at 420 nm and 450 nm. Using the modulated source and synchronous detector rather than a constant (DC) source eliminates measurement errors due to ambient light and low frequency noise and provides higher accuracy. In terms of software, we design a new quantitative analysis algorithm for absorbance by studying colloid absorbing behavior. The application of a buffer operator embedded in the algorithm makes the sensor get the environmental correction function. The results have shown that the sensitivity, repeatability, precision and environmental stability are higher than that by ordinary spectrophotometry. Lastly, we have a brief overview of future work.

[This corrects the article DOI: 10.1039/C7SC02967E.].

Abstract Background The gold standard of tumor diagnosis is histological examination of a biopsy; however, there is concern that tumor cell dissemination along the needle track during percutaneous biopsy can cause local tumor relapse. We aimed to evaluate the value of an adriamycin (ADM)-loaded gelatin sponge in preventing tumor cell contamination along the biopsy needle track. Methods Data were obtained from 40 patients who were diagnosed by core needle biopsy as having osteosarcoma and who were followed up at our hospital between 2008 and 2011. Of the 40 patients, 20 had the needle biopsy tracks filled with ADM-loaded absorbable gelatin sponge immediately after the biopsy specimen was obtained, while the other 20 did not. All 40 patients underwent limb-salvage surgery, and specimens were obtained from the biopsy track for histopathologic examination of multiple sections. Results On histological examination, there was less tumor cell contamination along the biopsy tracks in the ADM group. Conclusion Use of ADM-loaded absorbable gelatin sponge may prevent tumor cell contamination of a biopsy track, and reduce the possibility of consequent tumor relapse.

We present the validation of the hybrid sSSA-SDPD method for advection-diffusion-reaction problems coupled to discrete biochemical systems, as presented in the publication "A hybrid smoothed dissipative particle dynamics (SDPD) spatial stochastic simulation algorithm (sSSA) for advection-diffusion-reaction problems" (Drawert et al., 2019). We validate 1D diffusion, and 2D diffusion cases against their analytical solutions. We present graphs and tables of data showing the error in the simulation method.

Liquid crystalline networks (LCNs) are a class of polymers, which are able to produce mechanical actuation in response to external stimuli. Recent creation of LCNs with exchangeable links (xLCNs) makes LCNs easy moldable. As the xLCNs need to be shaped at a high temperature, it is important to enhance their thermal and mechanical properties. In this paper, a series of xLCNs/SiO₂ composites containing 1%-7% SiO₂ nanoparitcles (SNP) were prepared and their thermal and mechanical properties were examined. The results show that xLCNs/SNP composites have lower liquid crystalline-isotropic phase transition temperature and higher decomposition temperature than pure LCN. The tensile strength and the elongation at break of xLCNs at high temperatures were also enhanced due to the addition of SNPs.

In a ground war, achieving peace is challenging even when both sides suffer. Here we demonstrate that when humans jointly viewed a battlefield as perceptually grouped by colors, a factor irrelevant to the rules of land-war games, they waged fewer wars and accumulated more wealth due to the perceptual border’s constraint on their aggression. This facilitation of peace arose from perceptual grouping that serves as a visual common sense shared by humans, as a mismatched perceptual grouping between players failed to limit war. Moreover, it relies on the geopolitical principles that make ground wars destructive and disappeared when these principles were violated. Together, we show that perceptual grouping limits human ground war as it is a mutually acknowledged “rallying point” where expectations of peace converge.

Efficient and cost-effective solar steam generation requires self-floating evaporators which can convert light into heat, prevent unnecessary heat loss and greatly accelerate evaporation without solar concentrators. Currently, the most efficient evaporators (efficiency of ∼80% under 1 sun) are invariably built from inorganic materials, which are difficult to mold into monolithic sheets. Here, we present a new polymer which can be easily solution processed into a self-floating monolithic foam. The single-component foam can be used as an evaporator with an efficiency at 1 sun comparable to that of the best graphene-based evaporators. Even at 0.5 sun, the efficiency can reach 80%. Moreover, the foam is mechanically strong, thermally stable to 300 °C and chemically resistant to organic solvents.

We have developed a new algorithm which merges discrete stochastic simulation, using the spatial stochastic simulation algorithm (sSSA), with the particle based fluid dynamics simulation framework of smoothed dissipative particle dynamics (SDPD). This hybrid algorithm enables discrete stochastic simulation of spatially resolved chemically reacting systems on a mesh-free dynamic domain with a Lagrangian frame of reference. SDPD combines two popular mesoscopic techniques: smoothed particle hydrodynamics and dissipative particle dynamics (DPD), linking the macroscopic and mesoscopic hydrodynamics effects of these two methods. We have implemented discrete stochastic simulation using the reaction-diffusion master equations (RDME) formalism, and deterministic reaction-diffusion equations based on the SDPD method. We validate the new method by comparing our results to four canonical models, and demonstrate the versatility of our method by simulating a flow containing a chemical gradient past a yeast cell in a microfluidics chamber.