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关键词： Plant invasion   Species richness and composition   Managed forests   Soil nutrients   Phenolic compounds  

摘要： This study assessed the effects of invasive Quercus rubra on soil physicochemical properties and understory vegetation in native plant communities. Chemical properties of senesced tree leaves were also analysed. The study was performed at paired invaded-native plots in managed forests in southern Poland. Freshly fallen senesced leaves were characterized in terms of C, Ca, K, Mg, N, P, total phenolics and condensed tannins concentrations. Soil physicochemical parameters, namely bulk soil density, moisture, water holding capacity (WHC), pH, organic C, total Ca, K, Mg, N, P, exchangeable Ca, K, Mg, N-NH4, N-NO3, P-PO4, and total phenolics were analysed in organic and mineral soil horizons, and condensed tannins were analysed in organic soil horizon. The diversity, cover and composition of understory vegetation were assessed. Although, senesced leaves of Q. rubra and native trees, Quercus robur, Fagus sylvatica, Carpinus betulus and Acer pseudoplatanus among others, differed only in total K, N and C/N ratio, we observed considerable differences in soil physicochemical parameters between the plot types. Soil beneath Q. rubra was characterised by significantly lower WHC, organic C, total Mg, N, P, exchangeable Ca, Mg, N-NH4, N-NO3, total phenolics and higher moisture in organic and mineral soil horizons as well as lower content of P-PO4 and condensed tannins in organic soil horizon relative to native plant communities. Q. rubra negatively influenced species richness and cover of understory vegetation. The changes in soil physicochemical parameters and understory vegetation under Q. rubra may be associated with low quality (low N, high C/N) litter that decomposes slowly and generates a physical barrier, limiting seed germination and seedling growth. The changes in soil properties and vegetation under invasive Q. rubra indicate that this species may alter the structure and function of forest ecosystems and should be avoided in forest management practices.

关键词： Zn(II) complex   X-ray diffraction   Hirshfeld surface   CP-MAS-NMR spectroscopy   Hydrogen bonds  

摘要： A new 1-D polymeric zinc(II) complex derived from the neutral bidentate 2-amino-4,6-dimethoxypyrimidine ligand of formula [Zn2Cl4(C6H9N3O2)(2)](n) has been prepared and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. The Zn(II) cations are tetra-coordinated, in a tetrahedral fashion, by two nitrogen atoms from the pyrimidine ring of the organic ligand and two chloride anions. In the atomic arrangement, the bridge bidentate 2-amino-4,6-dimethoxypyrimidine ligands and the tetra-connected Zn centers link each other to give a 1-D corrugated chain with molecular formula [Zn2Cl4(C6H9N3O2)(2)](n) running along the b-axis direction. These chains, located at z = (2n+1)/4, are interconnected via C-H center dot center dot center dot Cl- hydrogen bonds to form layers parallel to the (a, c) plane and crossing the unit cell at y = 1/2. These layers are, in turn, connected to each other via C-H center dot center dot center dot Cl- hydrogen bonds to form a three-dimensional supramolecular network. Intermolecular interactions were investigated by Hirshfeld surfaces. The two independent organic ligands show very similar contacts and electrostatic environments. Electronic properties such as HOMO and LUMO energies were derived. The vibrational absorption bands were identified by infrared spectroscopy. This compound was also characterized by thermal analysis to determine its thermal behavior. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Cocoa butter   Cocoa butter substitute   Cuminum cyminum L. essential oil   Encapsulation   Nano caner  

摘要： The main objective of this study was to encapsulate of the essential oil of Cuminum cyminum L. with cocoa butter (CB) and cocoa butter substitute (CBS) as lipid carriers in order to overcome the low solubility of the essential oil in water, to increase its bioavailability and to protect of essential oil in the environmental conditions. The nano lipid carrier containing Cuminum cyminum essential oil (NW) was prepared by homogenization assisted with sonication method. Physicochemical properties including particle size and polydispersity index (POI), encapsulation efficiency, turbidity and zeta potential and antioxidant activity of the system were studied. The release of essential oil in the simulated condition of the gastric and intestinal was examined. The results showed that all lipid carrier formulations containing Cumin= cyminum essential oil had very small particle size (less than 150 nm) and their encapsulation efficiency was greater than 80%. The zeta potential of the lipid carrier was changed from -9 to -4.4 (mV) with the addition of Cuminum cyminum essential oil. The stability of the nano carriers during one month showed that the particle size of the samples was less than 150 nm over time. The physical properties of the coated essential oil did not decrease significantly in 30 days while the uncoated essential oil physical properties were reduced significantly. The results showed that the encapsulation of essential oil with lipid coatings causes controlled release of essential oil in the gastrointestinal tract. It can be concluded that the nano lipid carrier containing Cuminum cyminum essential oil can be used in foods, especially beverages. (C) 2020 Published by Elsevier B.V.

关键词： Garlic   Freeze-thaw cycles pretreatment   Vacuum freeze-drying process   Physicochemical properties   Polysaccharides  

摘要： Freeze-thaw cycles (FTC) pretreatment was employed before the vacuum freeze-drying of garlic slices, aimed at improving the drying process and the quality of the end product. Cell viability, water status, internal structure, flavor, chemical composition and thermogravimetric of garlic samples were evaluated. The results indicated that FTC pretreatment reduced the drying time (22.22%-33.33%) and the energy consumption (14.25%-15.50%), owing to the water loss, the increase in free water, and the formation of porous structures. The FTC pretreatment improved thermal stability, flavor and chemical composition content of dried products. The antioxidant activity of polysaccharides extracted from FTC pretreated dried products was higher than that of the unpretreated dried product due to the reduction in polysaccharide molecular weight. This research could pave a route for future production of dried garlic slices having good quality by using the FTC pretreatment, with lower energy consumption and shorter drying time.

关键词： Titanium   Keratin   Functionalization   Coating  

摘要： Coupling of keratin with titanium surfaces is here realized both through thick coatings and molecular functionalization. This coupling has the final aim both of chemical and mechanical protection of the titanium surfaces and of improving interaction of titanium implants with soft tissues in transmucosal and percutaneous implants. Wool-derived keratin has been used and plasma decontamination/activation has been tested as possible strategy for the improvement of keratin grafting ability and adhesion. Coated/functionalized surfaces have been characterized by means of X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscopy (SEM), contact angle measurements X-Ray Diffraction (XRD), zeta potential and adhesion (tape and scratch) tests. These analyses evidenced that keratin was successfully coupled to titanium surfaces both in the form of molecular grafting and thick coating. In both cases, plasma surface activation improves keratin wetting and bonding ability for the substrates. The obtained coatings showed good adhesion and mechanical stability.

关键词： 3,5-Dinitrobenzoic acid   Proton transfer mechanism   Detonation velocity   Detonation pressure   HEDMs  

摘要： Hydrogen bonded proton transfer crystals 1-4 were synthesized, using substituted azoles and 3,5-dinitrobenzoic acid, in a ratio 1:1 and ethanol as solvent at room temperature. The structure elucidation for the synthesized energetic crystals was carried out using spectral techniques such as, IR, H-1, and C-13 NMR spectroscopy. The formation of proton transfer complexes occurred due to the transfer of lone pair of electrons from the donor azoles such as 3-nitropyrazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, and 5-aminotetrazole to the acceptor 3,5-dinitrobenzoic acid through N+-H center dot center dot center dot O- type of hydrogen bond and was ascertained by X-ray crystallographic and proton NMR studies. Mathematical calculations propounded by various scientists are used to determine the explosive properties. The thermal stability was carried out using DSC-TGA studies. Sensitivity parameters were also calculated for the synthesized compounds. The results indicated that the proton transfer complexes are more stable, insensitive to impact, have high energetic parameters and thus classified into the category of High-energy-density materials (HEDMs). The high nitrogen content compounds gives out nitrogen gas (N-2) as major detonation product, which will burn cleanly, producing less carbon monoxide and paving the way for new generation of environmentally compatible energetic materials. (c) 2020 Elsevier B.V. All rights reserved.

关键词： Sn(IV) complex   Hirshfeld surface   X-ray diffraction   DFT calculation   Luminescence property  

摘要： X-ray structure of a new hybrid organic-inorganic compound, piperazine-1,4-diium hexachlorostannate(IV) trihydrate (C4H12N2)[SnCl6]center dot 3H(2)O has been determined. The title compound crystallizes in the chiral orthorhombic space group P2(1)2(1)2(1)with Flack parameter 0.44(6) and a = 9.6006(3) angstrom, b = 11.4705(5) angstrom, c = 14.3876(4) angstrom and V = 1584.42(10) angstrom(3). The atomic arrangement can be described by alternation of organic chains and inorganic ribbons. The crystal packing is stabilized by hydrogen bonds and van der Waals interactions. The 3D Hirshfeld surfaces and the associated 2D fingerprint plots were investigated for intermolecular interactions. The powder XRD pattern was in good relation with the results of single crystal structure analysis. Scanning electronic microscopy (SEM) and energy-dispersive X-ray (EDX) were carried out. The vibrational absorption bands were identified by IR spectroscopy and were also calculated by Density Functional Theory (DFT). A good consistency was found between the calculated and experimental data. The optical property of the crystal was studied using optical absorption UVevisible and exhibited one large band at 250 nm and photoluminescence measurements showed emission at 409 nm. Finally, the thermal analysis shows that this compound is stable below 380 K. (c) 2020 Elsevier B.V. All rights reserved.

关键词： Relative stabilities   Germanium clusters   Density functional theory DFT   Binding energies   Magnetic properties  

摘要： We present a theoretical study on the equilibrium geometries, energetic, electronic, and magnetic characteristics of BGen (n = 1-20) clusters using the density functional theory (DFT) calculations. The most stable structures display a B atom located at the surface of BGen clusters, except for BGe9, 12, 16, 18, 19, 20. Larger clusters reveal higher binding energy, suggesting their greater stability compared to the corresponding Gen+1 clusters. The calculated fragmentation energy, second-order energy difference, and HOMO-LUMO energy gap reveal that the BGe9, 12 clusters are more stable than other cluster sizes. The calculated magnetic properties of the lowest-energy BGen clusters display a total spin magnetic moment equal to 1 mu B, except for the BGe cluster, which takes the value 3 mu(B). These findings can be useful to the experimentalists in designing new Nano-catalytic systems.

关键词： Levanase   Cross-linked enzyme aggregates   Fructooligosaccharides  

摘要： Short-chain fructooligosaccharides (scFOSs) can be produced from the levan hydrolysis using levanase. Levanase from Bacillus lehensis G1 (rlevblg1) is an enzyme that specifically converts levan to scFOSs. However, the use free levanase presents a lack of stability and reusability, thus hindering the synthesis of scFOSs for continuous actions. Here, CLEAs for rlevblg1 were prepared and characterized. Cross-linked levanase aggregates using glutaraldehyde (CLLAs-ga) and bovine albumin serum (CLLAs-ga-bsa) showed the best activity recovery of 92.8% and 121.2%, respectively. The optimum temperature of CLLAs-ga and CLLAs-ga-bsa was increased to 35 degrees C and 40 respectively, from its free rlevblg1 (30 degrees C). At high temperature (50 degrees C), the half-life of CLLAs-ga-bsa was higher than that of free rlevblg1 and CLLAs-ga. Both CLLAs exhibited higher stability at pH 9 and pH 10. Hyperactivation of CLLAs-ga-bsa was achieved with an effectiveness factor of more than 1 and with improved catalytic efficiency. After 3 h reaction, CLLAs-ga-bsa produced the highest total scFOSs yield of 35.4% and total sugar of 60.4% per gram levan. Finally, the reusability of CLLAs for 8 cycles with more than 50% activity retained makes them as a potential synthetic catalyst to be explored for scFOSs synthesis. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Proso millet   Genetic diversity   Starch physicochemical properties  

摘要： In this study, 95 accessions of proso millet (Panicum miliaceum L.) were characterized for starch physicochemical properties, including apparent amylose content (AAC), gel textural properties, Rapid Visco Analyzer (RVA) pasting viscosity properties, thermal and retrogradation properties. Based on genotypic data, the genetic diversity and inter-relationship of these starch traits were analyzed. Diverse starch quality was found, for example, AAC ranged from 0 to 32.3%, gelatinization temperature (GT) varied from 71.5 to 79.0., and RVA profile showed distinct patterns among proso millet of different AAC types. Interestingly, high AAC proso millet usually had GT lower than that of low AAC proso millet, which is different from the findings in rice starch. Many starch traits were significantly correlated and most of the 18 tested traits could be classified as either AAC-related traits or GT-related traits. In summary, the information presented here will be useful for further development of proso millet products.