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旨在为迷迭香脂溶性提取物在食用油保鲜方面的应用提供参考，以玉米油提取的迷迭香脂溶性提取物（可作为抗氧化剂）为原料，对其进行脱色处理，以脱色率为指标，通过单因素试验和响应面试验优化脱色工艺条件，并采用高效液相色谱法测定脱色前后迷迭香脂溶性提取物中脂溶性抗氧化成分（鼠尾草酸和鼠尾草酚）的含量。结果表明：与活性白土及活性白土与活性炭复配（质量比1∶ 1、1∶ 2、2∶ 1）脱色剂相比，活性炭对迷迭香脂溶性提取物的脱色效果最好，最佳脱色工艺为活性炭添加量2.1%、脱色温度50 ℃、脱色时间59 min，在此条件下脱色率为(75.02±0.37)%；脱色前后迷迭香脂溶性提取物中脂溶性抗氧化成分含量分别为4.065 5%和3.883 6%。综上，优化条件下迷迭香脂溶性提取物的脱色效果较好，且脱色对其脂溶性抗氧化成分含量影响较小。In order to provide a reference for the application of rosemary fat-soluble extract in the preservation of edible oil, the rosemary fat-soluble extract (which can be used as an antioxidant) extracted by corn oil was decolorized. With the decolorization rate as the index, the decolorization process conditions were optimized by single factor experiment and response surface methodology, and the content of fat-soluble antioxidant components (carnosic acid and carnosic phenol) in rosemary fat-soluble extract before and after decolorization was determined by high performance liquid chromatography. The results showed that activated carbon had the best decolorization effect on rosemary fat-soluble extract compared with activated clay and compound decolorant of activated clay and activated carbon (mass ratio 1∶ 1,1∶ 2,2∶ 1). The optimal decolorization process conditions were as follows: activated carbon dosage2.1%, decolorization temperature 50 ℃, decolorization time 59 min. Under the optimal conditions, the decolorization rate was (75.02±0.37)%. The antioxidant content before and after decolorization in rosemary fat-soluble extract was 4.065 5% and 3.883 6%, respectively. In summary, the decolorization effect of rosemary fat-soluble extract under optimized conditions was better, and the decolorization had little effect on the content of fat-soluble antioxidant components.

BACKGROUND Wastewater containing heavy metals produced by mining, beneficiation, smelting, forging, processing, transportation, and other industries that has been improperly disposed of, leads to heavy metals entering and polluting the groundwater environment. Heavy metals can be enriched in the human body and participate in the biological cycle. Long-term accumulation of heavy metals in the human body will bring carcinogenic, teratogenic, and mutagenic risks. Adsorption has been of wide concern in the treatment of heavy metals pollution in water, due to the advantages of low operation cost, simple engineering operation and low secondary pollution. Chitosan as a natural organic polysaccharide organic matter, has the characteristics of being environmentally friendly. It contains many nitrogen-containing functional groups that can adsorb metal ions in water. However, the adaptability of chitosan adsorbents to acidic conditions is poor, so the pH value needs to be adjusted in the actual process, which increases the operating cost. Combining biochar with chitosan can not only improve the adsorption capacity of chitosan, but also improve the separation performance of biochar. However, most of the research on chitosan modified biochar concentrate on the single biochar. There are few studies on the modification of biochar from different sources by chitosan, and the interaction between chitosan and biochar is not clear. OBJECTIVES The aim of this study was to prepare peanut shell biochar-chitosan magnetic composite adsorbent (PSC) and corn cob biochar-chitosan magnetic composite adsorbent (CCC), and to investigate the Pb2+/Cu2+ adsorption properties and mechanisms on PSC and CCC. METHODS Scanning electron microscope was used to analyze the microstructure of the material, and the material samples were treated with gold spray before photographing. The specific surface area and pore volume of the material were determined using a specific surface area analyzer, and the material was adsorption-desorption tested with nitrogen at -196℃. X-ray diffraction was used to analyze the crystal structure of materials, and the Cu Kα source was used to scan in the range of 10°-80° (2θ). X-ray photoelectron spectrometer was used to analyze the changes of functional groups on the surface of the material, and the radiation (225W, 15mA, 15kV) was carried out by monochromatic Al-Kα. Metal ion content in solution was measured by inductively coupled plasma-optical emission spectrometry. The adsorption experiments were carried out in a 50mL conical flask and a constant temperature shaker. The oscillation frequency was 150r/min and the reaction time was 12h. After the reaction, the concentrations of Pb2+ and Cu2+ in the solution were determined. Two parallel samples were set up in each group. Different initial pH experiments were used to evaluate the adsorption performance of materials. Kinetic and isothermic models were used to evaluate the adsorption kinetic process of materials and predict the maximum adsorption capacity of materials. Recycling experiments and actual mine groundwater adsorption experiments were used to evaluate the practical application capacity of materials. RESULTS SEM images of PS and CC showed that there were many pores on the surface of both types of carbon. There were more pores and bulges observed on the surface of CC than PS, indicating that CC had a larger contact area with pollutants than PS. The specific surface area (12.045m2/g) and mean pore diameter (3.614nm) of CC were larger than those of PS (specific surface area was 3.294m2/g and mean pore diameter was 3.067nm), which was consistent with the SEM results. The specific surface area (4.598m2/g) and average pore diameter (3.417nm) was 2.812nm), indicating that the primary structural properties of biochar affected the pore structure of the composites. SEM of CCC and PSC showed that chitosan and biochar were well combined. Compared with previous literature, the biochar-chitosan composite material in this study preserves the original structure of biochar to the greatest extent, and makes the chitosan evenly coated on the surface of biochar. The results BET showed that the primary structural properties of the biochar affected the physical properties of the modified materials. The XRD results showed that Fe3O4 was successfully embedded into the composite material. Three pH values (4, 7 and 10) were selected to evaluate the swelling properties of the materials. The results showed that the swelling ratios of the two materials were similar under the three pH conditions, and neither of them was more than 100.0%, which was due to the biochar as a carrier having a good supporting effect. Compared with chitosan/kiwifruit branch biochar adsorbent, the two adsorbents in this study showed relatively stable adsorption properties in the pH range of 4-7, indicating that the adsorbents had a wider range of pH value application. The effect of the initial pH on the adsorption was tested. As the initial pH value increased from 3 to 7, the adsorption capacity and removal efficiency of the material increased. The positive charge of the adsorbent surface also decreased, which reduced the electrostatic repulsion of Pb2+ and Cu2+ between the material surface and the solution, and increased the electrostatic attraction between the material surface and Pb2+ and Cu2+. The increasing electrostatic attraction was beneficial to the adsorption of Pb2+ and Cu2+. When PSC and CCC adsorbed Pb2+, the pseudo-first-order kinetic model could better describe the adsorption process than the pseudo-second-order kinetic model, indicating that physical adsorption played a dominant role in the adsorption of Pb2+ by PSC and CCC. Pseudo-second-order kinetics can better fit the Cu2+ adsorption by PSC and CCC than pseudo-second-order kinetic model, indicating that chemisorption dominates the adsorption process of Cu2+ by PSC and CCC. The Langmuir isotherm adsorption model can better describe the adsorption process of Pb2+ and Cu2+ than Freundlich isotherm adsorption model, indicating that the adsorption process is monolayer adsorption. The EDTA-2Na was used as the desorption agent of chitosan composite, the removal efficiencies of Pb2+ and Cu2+ were still above 85% after five cycles, which indicated that the two adsorbents in this study had excellent stability. PSC and CCC were the low-cost and effective adsorption materials. Groundwater of an acid mine was taken from a mining area in Dongshan District, Dafan Mountain, Anhui Province. The groundwater samples contained large amounts of metal ions, such as As, Ca, Cd, Cu, Fe, Mn, Na and Ni, the corresponding concentrations were 18.200g/L, 40.541mg/L, 3.800g/L, 13.300mg/L, 215.00mg/L, 510.00g/L, 81.694mg/L and 87.000g/L, respectively. 0.45μm filter membrane was used to remove particulate impurities from the water before adsorption. CCC was used to treat the heavy metal polluted groundwater, and the results showed that CCC has a good removal ability on a variety of metal ions in groundwater such as Cu2+, Cd2+, and Fe3+. The Cu2+ concentration in the treated water can reach the Grade IV water standard of the “Groundwater Quality Standard”. The pH results showed that the removal mechanisms of Pb2+ and Cu2+ by PSC and CCC mainly included electrostatic attraction. The functional groups of adsorbents before and after adsorption were analyzed through X-ray photoelectron spectroscopy (XPS). The results of XPS showed that complexation was another removal mechanism. The nitrogen (—NH) of pyrroles, amino of chitosan (—NH2), and C=N were the main functional groups, which were responsible for the complexation with Pb2+ and Cu2+. CONCLUSIONS The preparation method of the materials in this study can effectively improve the adaptability of chitosan materials under different pH conditions. The adsorbents developed in this study can effectively remove heavy metals from groundwater and have a good application potential.

Peel browning disorder has an enormous impact on the exterior quality of 'Huangguan' pear whereas the underlying mechanism is still unclear. Although different methods have been applied for inhibiting the peel browning of 'Huangguan' pear, there are numerous issues associated with these approaches, such as time cost, efficacy, safety and stability. In this study, to develop a rapid, efficient and safe way to protect 'Huangguan' pear from skin browning, the effect of exogenous ethylene on peel browning of pear fruits stored at 0°C was evaluated. Results showed that ethylene treatments at 0.70-1.28 μL/L significantly decreased the browning rate and browning index from 73.80% and 0.30 to 6.80% and 0.02 after 20 days storage at 0°C, respectively, whereas ethylene treatments at 5 μL/L completely inhibited the occurrence of browning. In addition, ethylene treatments at 5 μL/L decreased the electrolyte leakage and respiration rate, delayed the loss of total phenolic compounds. Furthermore, ethylene (5 μL/L) treatment significantly enhanced the activity of catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) and increased the 1, 1-diphenyl-2-picrylhydrazyl inhibition rate, but inhibited the activity of polyphenol oxidase (PPO) and peroxidase (POD). Our data revealed that ethylene prevented the peel browning through improving antioxidant enzymes (CAT, APX and SOD) activities and reducing PPO activity, electrolyte leakage rate and respiration rate. This study demonstrates that exogenous ethylene application may provide a safe and effective alternative method for controlling browning, and contributes to the understanding of peel browning of 'Huangguan' pear.

A heteropolytungstate cluster [{Ru2O(bpy)2}2{Bi2W32O110}]10− (bpy = C10H8N2) was incorporated into a 2 : 1 type layered porous framework by interweaving the Na+ bridged cluster chains through the hydrogen bonding ability of the bpy ligands. It features multiple pore channels rich in hydrogen-bond network, contributing high conductivities > 10−2 S cm−1 at 298–358 K and 85% RH. [ABSTRACT FROM AUTHOR]

Building information modeling (BIM) is a pivotal technology to realizing the digital transformation of the construction industry. Lack of BIM professionals, however, is one of the reasons the application of BIM technology in the construction industry is hindered. Identifying BIM competency requirements is critical for BIM professionals' training. This paper uses the structural topic model (STM) to mine the topics of BIM recruitment information to deeply understand the BIM competency requirements from a 360° view of the construction industry. The company size, salary level, year of experience, and education in BIM recruitment information are taken as covariates to examine their impact on BIM recruitment topic prevalence. And the changing trend of the topic prevalence and topic correlations are observed through visual analysis. The results reveal that the current BIM competency requirements in the construction industry contain three aspects: management competencies, professional and technical competencies, and personal characteristics. In particular, the requirements for BIM application, construction drawing design, and information technology (IT) skills are relatively strong, and personnel professionalism is also a concern of BIM job recruitment. Companies of different sizes have evident preferences for competencies. Salary levels and years of experience requirements also affect the intensity of corporate demand for BIM competencies. However, education is not the main factor affecting the recruitment of BIM positions. The results can provide a reliable theoretical basis for educational institutions to build a proper BIM professional course system, for companies to develop BIM job recruitment plans, and for individuals to choose their employment goals. [ABSTRACT FROM AUTHOR]

To acquire a superior microwave absorber, ZnO/Fe3O4 nanoparticles have been successfully embedded into an N-doped honeycomb-like porous carbon (NPC) framework via a two-step process. The structure, morphology, and electromagnetic wave absorption properties of ZnO/Fe3O4/NPC composites have been characterized. Benefitting from the unique hierarchical porous architecture, the balanced impedance between ZnO and Fe3O4, and the synergistic effects between ZnO/Fe3O4 nanoparticles and the carbon matrix, ZnO/Fe3O4/NPC exhibited an outstanding electromagnetic wave absorption performance. The minimum reflection loss (RL) could reach − 51.1 dB at 12.9 GHz when the thickness is 3.7 mm, with a wide effective absorption bandwidth (RL ≤ 10 dB) of 5.28 GHz at a thickness of 2.2 mm. It is apparent that ZnO/Fe3O4/NPC has great potential as a high-efficiency microwave absorber. [ABSTRACT FROM AUTHOR]

Glycoprotein (GP) Ibα shedding mediated by ADAM17 (a disintegrin and metalloproteinase 17) plays an important role in negatively regulating platelet function and thrombus formation. However, the mechanism of GPIbα shedding remains elusive. Here, we show that jasplakinolide (an actin-polymerizing peptide)-induced actin polymerization results in GPIbα shedding and impairs platelet function. Thrombin and A23187-induced GPIbα shedding is increased by jasplakinolide; in contrast, GPIbα shedding is reduced by a depolymerization regent (cytochalasin B). We find that actin polymerization activates calpain leading to filamin A hydrolyzation. We further demonstrate that the interaction of filamin A with the cytoplasmic domain of GPIbα plays a critical role in regulating actin polymerization-induced GPIbα shedding. Taken together, these data demonstrate that actin polymerization regulates ADAM17-mediated GPIbα shedding, suggesting a novel strategy to negatively regulate platelet function. [ABSTRACT FROM AUTHOR]