Ag modified ZnO nanoflower gas sensitive sensor for selective detection of n-butanol.

Ag modified ZnO nanoflowers were successfully prepared by sunlight induced solvent reduction method. The samples were characterized by XRD, FESEM, TEM and EDS, and the results confirmed the presence of Ag nanoparticles on the ZnO nanoflower. The gas sensing performance of the materials was studied at different operating temperatures and different n-butanol concentrations. The results showed that the Ag modified ZnO nanoflower sensor responded to 50 ppm n-butanol up to 147.17 at 280 °C, and the Ag modified ZnO nanoflower sensor exhibited excellent repeatability, stability and response recovery time. In addition, different target gases were employed for the selectivity study of the Ag modified ZnO nanoflower. It can be found that the Ag modified ZnO nanoflower had good selectivity for n-butanol. The improved response of the Ag modified ZnO nanoflower sensor was attributed to the catalytic effect of Ag nanoparticles. The results indicate that the Ag modified ZnO nanoflower will become a very promising sensing material for n-butanol gas detection. .

[Learning and Memory Capacity and NMDA Receptor Expression in Shen Deficiency Constitution Rats].

OBJECTIVE: To explore material bases and neurobiological mechanisms of "Shen storing will" by observing learning and memory capacities and N-methyl-D-aspartic acid (NMDA) receptor expressions in Shen deficiency constitution (SDC) rats. METHODS: Totally 40 SD rats were randomly divided into the model group, the Zuogui Pill (ZP) group, the Yougui Pill (YP) group, the blank control group (consisting of normal pregnant rats), 10 in each group. SDC young rat model (inherent deficiency and postnatal malnutrition) was prepared by the classic way of "cat scaring rat". Medication started when they were scared by cat. Rats in the ZP group and the YP group were administered by gastrogavage with ZP suspension 0.1875 g/mL and YP suspension 0.0938 g/mL respectively. Equal volume of normal saline was administered to rats in the blank control group and the model group by gastrogavage. All medication was given once per day, 5 days in a week for 2 consecutive months. Learning and memory capacities were detected by Morris water maze test. Expressions of NMDA receptor subunits NR2A and NR2B in hippocamus were detected by immunohistochemical method. RESULTS: Compared with the blank control group, the latency period, total distance in Morris water maze test were longer in the model group (P < 0.05). All the aforesaid indices all decreased in the ZP group and the YP group, with statistical difference when compared with the model group (P < 0.05). The protein expressions of NR2A and NR2B in hippocamus were lower in the model group than in the blank control group (P < 0.05). But when compared with the model group, they were obviously higher in the ZP group and the YP group (P < 0.05). CONCLUSIONS: SDC rats had degenerated learning and memory capacities and lowered NMDA receptor expressions. ZP and YP could up-regulate learning and memory capacities and NMDA receptor expressions, thereby improving deterioration of brain functions in SDC rats.

APF-S2T: Steering to Target Redirection Walking Based on Artificial Potential Fields.

Redirected walking (RDW) enables users to walk naturally within a virtual environment that is larger than the physical environment. Recently, several artificial potential field (APF) and alignment-based redirected controllers have been developed and have been demonstrated to significantly outperform conventional controllers. APF Steer-to-Gradient (APF-S2G) and APF Redirected Walking (APF-RDW) utilize the negative gradient and the total force vector, respectively, which are localized to the user's position. These vectors usually point towards the opposite wall when the user is in corridors, resulting in frequent resets within those regions. This paper introduces the APF Steer-to-Target (APF-S2T), a redirected controller that first finds the target sample point with the lowest score in the user's walkable area in both physical and virtual environments. The score of a sample point is determined by the APF value at the point and the distance from the user's position. The direction from the user's position to the target point is then used as the steering direction for setting RDW gains. We conducted a simulation-based evaluation to compare APF-S2T, APF-S2G, APF-RDW, Visibility Polygon-based alignment (Vis.-Poly.) and Alignment-Optimized controllers in terms of the number of resets and the average distance between resets. The results indicated that APF-S2T significantly outperformed the state-of-the-art controllers.

Effects of microplastics on N2O production and reduction potential in crop soils of northern China.

Microplastics (MPs) pollution are found to be increasing in vegetable soils and potentially affecting N2O production and their associated pathways; however, its specific effects remain unclear. Here, we selected two common MPs, PE and PP at four different concentration levels of 0, 0.5, 1.5 and 3%, and conducted several incubation experiments aiming to explore soil bacterial and fungal N2O production. Results showed that the bacteria were the main contributors for the production of N2O, regardless of the absence or presence of MPs; and its contribution was decreased with increasing concentrations of PE and PP. The nosZ clade I and II genes were positively correlated with N2O reduction rates, indicating a combined regulation on soil N2O reduction. PE significantly inhibited the bacterial nitrification and denitrification, but did not affect the total N2O production rates; while PP significantly reduced both the bacterial and fungal N2O production rates. The resistance of fungal N2O production to MPs pollution was stronger than that of the bacterial N2O production. It highlights that the MPs pollution could reduce the potential of N2O production and reduction, and thus disturb soil nitrogen cycling system; while the inhibition on N2O production via bacteria and fungi varies with different types of MPs. This study is conducive to an improved and more comprehensive understanding of the ecological impacts of MPs within the agroecosystem.

Potential of yak dung-derived hydrochar as fertilizer: Mechanism and model of controlled release of nitrogen.

Improving fertilizer efficiency with assistance of biochar has drawn much attention in sustainable agriculture. Promoting slow-release properties of biochar itself with cost-effective production technology is a pressing demand. In this study, hydrochar derived from nutrition-enriched yak dung (HC) and corresponding controlled release nitrogen fertilizer (HCRNF) via HCl modifying were studied, and the slow release performance as well as mechanisms were investigated. The results show that HCRNF presents a better N controlled-release performance with cumulative N release amounts of 56.01%-70.30% compared with 72.60%-78.45% of HC. The specific surface area reached highest 47.161 m2·g-1 in HCRNFs with the pore volume of 0.098 cm3·g-1. Hydrochloric acid modification treatment increases the surface acid group contents such as phenolic hydroxyl group content increasing to 1.48 mmol·g-1 in HCRNF250. Because the porous structure and stable internal force between N and O-containing functional groups are improved, the N desorption from HCRNF is retarded, which shows a controlled release behavior. We concluded that the HCRNF via HCl modification in this work has a great application potential as slow released N fertilizer in sustainable green agriculture.

[Advances in bioremediation of hydrocarbon-contaminated soil].

With continuous improvement of people's living standards, great efforts have been paid to environmental protection. Among those environmental issues, soil contamination by petroleum hydrocarbons has received widespread concerns due to the persistence and the degradation difficulty of the pollutants. Among the various remediation technologies, in-situ microbial remediation enhancement technologies have become the current hotspot because of its low cost, environmental friendliness, and in-situ availability. This review summarizes several in-situ microbial remediation technologies such as bioaugmentation, biostimulation, and integrated remediation, as well as their engineering applications, providing references for the selection of in-situ bioremediation technologies in engineering applications. Moreover, this review discusses future research directions in this area.

[Qualitative and quantitative methods of betulonic acid in fruits of Liquidambar formosana].

OBJECTIVE: To develop the identification and assay methods for betulonic acid in fruits of Liquidambar formosana. METHOD: TLC method was used for identification with silica gel G plate and petroleum ether(60-90 degrees C)-acetone (17:3) as a developing solvent. Betulonic acid in ethanol extract was separated on the ODS column with methanol-water-glacial acetic acid (87:13:0.1) as mobile phase. Flow-rate was 1.0 mL x min(-1), and column temperature 35 degrees C. ELSD drift-tube temperature was 82 degrees C, and gas flow 1.25 L x min(-1). RESULT: The qualitative method is repeatable. Betulonic acid in ethanol extracts is well separated, relationship of logarithms of injection amount and peak area is linear (r = 0.9997) within the range of 0.65-3.25 microg. The average recovery is 98.0% and RSD of repeatability is 2.5%. 11 crude drugs purchased from different areas in the country were identified and quantified with the methods. CONCLUSION: The methods and data could be used for quality control of fruits of L. formosana.

[Chemical composition of fructus Liquidambaris--lulutong].

AIM: To study the chemical composition in the fruits of Liquidambar formana Hance. METHODS: Various column chromatographic techniques were used to separate and purify the constituents. Their physical and chemical properties and spectral data were measured for structural elucidation. RESULTS: Eleven compounds were isolated and identified as beta-sitosterol (1), 3-oxo-11 alpha, 12 alpha-epoxyleanan-28, 13 beta-olide (2), 3-oxo-12 alpha-hydroxy-oleanan-28, 13 beta-olide (3), 3 alpha-acetyloxy-25-hydroxyolean-12-en-28-oic acid (4), oleanolic acid (5), ursolic acid (6), daucosterol (7), betulonic acid (8), gallic acid (9), nonacosane (10) and n-triacontanoic acid (11). CONCLUSION: Among the isolated constituents, compound 4 is new compound, compound 3 is firstly isolated from the natural product and compound 5, 6, 7, 9, 10 and 11 are isolated from LuLuTong for the first time.

[Advances of nuclear translation factor:peroxisome proliferator-actived receptor gamma2].

Peroxisome proliferator-actived receptor gamma2(PPARgamma2) is a translation factor that belongs to the superfamily of nuclear receptors. It expresses predominantely in adipose tissue and has a key role in adipocyte differentiation. The common Pro12Ala polymorphism is associated closely with obesity and type 2 diabetes. It is the target molecular of thiazolidinediones which is a novel class of insulin sensitizer. The study of PPARgamma2 molecular mechanism of metabolism control may accelerate the finding of new drug targets in prevention and therapeution of type 2 diabetes.