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关键词： Stiffness   Vesicles   Lipids   Fluorescence   Membranes  

摘要： Exosomes mediate communication between cells in the body by the incorporation and transfer of biological materials. To design an artificial liposome, which would mimic the lipid composition and physicochemical characteristics of naturally occurring exosomes, we first studied the physicochemical properties of exosomes secreted from HepG2 cells. The exosome stiffness obtained by atomic force OOPS: a hped microscopy was moderate. Some liposomes were then fabricated to mimic the representative reported lipid composition of exosomes. Their physicochemical properties and cellular internalization efficiencies were investigated to optimize the cellular internalization efficiency of the liposomes. A favorable internalization efficiency was obtained by incubating HeLa cells with 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)/cholesterol (Chol)/1,2-dioleoyl-snglycero-3-phospho-L-serine (DOPS) (40/40/20 mol %) liposomes, which have a similar stiffness and zeta potential to exosomes. A dramatic increase in internalization efficiency was demonstrated by adding DOPS to simple DSPC/Chol liposomes. We found that DOPS had a more desirable effect on cellular internalization than its saturated lipid counterpart, 1,2-distearoyl-sn-glycero-3-phospho-L-serine. Furthermore, it was shown that the phosphatidylserine-binding protein, T-cell immunoglobulin mucin protein 4, was largely involved in the intracellular transfer of DSPC/Chol/DOPS liposomes. Thus, DOPS was a key lipid to provide the appropriate stiffness, zeta potential, and membrane surface affinity of the resulting liposome. Our results may help develop efficient drug carriers aiming to internalize active substances into cells.

关键词： Thin films   Monomers   Photovoltaics   Molecular structure   Polymers  

摘要： Combining the acceptor-donor-acceptor-type fused ring-based molecular architecture into a polymeric backbone is a promising strategy to design polymer acceptors for high-performance all-polymer solar cells (all-PSCs), and use of single isomer monomers is critical to control their physicochemical and photovoltaic properties. Here, two polymer acceptors (namely, PBI-alpha and PBI-beta) based on two different building blocks are designed and synthesized for investigating the effect of regioisomerism of the building blocks on the physicochemical and photovoltaic properties of the polymer acceptors. The subtle difference in the thienyl-fused malononitrile group of PBI-alpha and PBI-beta significantly influences their absorption spectra and electronic energy levels. PBI-alpha exhibited a lower lowest unoccupied molecular orbital level and obviously redshifted absorption spectrum compared to PBI-beta, which delivered a significantly different open-circuit voltage (0.930 +/- 0.004 vs 1.02 +/- 0.01 V) and short-circuit current density (18.7 +/- 0.3 vs 16.1 +/- 0.4 mA cm(-2)) in the PBI-alpha- and PBI-beta-based devices, respectively. Meanwhile, PBI-beta shows a more positive molecular packing effect to enhance the pi-face-on orientation backbone stacking of polymer donor PM6 than PBI-alpha, which is beneficial for efficient charge transport, leading to a higher fill factor of 0.684 in the PBI-beta-based all-PSC compared to 0.646 for the PBI-alpha-based device.

关键词： Azotobacter   enzyme activity   grain yield   micronutrient   water stress  

摘要： Field trial was conducted to study the effect of nanofertilizer and biofertilizer on physicochemical properties and grain yield of wheat (Triticum aestivum L.) under different irrigation levels. The treatments included four nanofertilizers (no nanofertilizer, nano zinc (Zn) oxide, nano iron (Fe) oxide, and nano Zn-Fe oxide, each 1.5 g L-1), four biofertilizer (without inoculation, seed inoculation by Azotobacter, Azosperilium, and Pseudomonas), and three irrigation levels (normal irrigation, moderate and severe water limitation). Results indicated that water limitation led to a decrease in the grain yield, photosynthetic pigments, efficiency of photosystem II, and relative water content whereas, increased proline, soluble sugars, and activities of catalase, peroxidase, and polyphenol oxidase. The application of biofertilizers and nanooxides increased the proline, soluble sugars, and enzyme activities. Relative to control plants (without nanooxide), the plants treated with oxide nanoparticles of Zn-Fe had 17% lower electrical conductivity, 27% higher peroxidase activity, and 61% higher polyphenol oxidase under severe water limitation. The application of Azotobacter and nano Zn-Fe oxide caused 88% increase in the grain yield as compared to control under severe water limitation. Our study implies that the combined application of biofertilizer and nano Zn-Fe oxide improved wheat yield under drought stress.

关键词： Persian lime seed   Physical properties   Cold pressing   Solvent extraction   Physicochemical properties  

摘要： In this study, some physical properties of Persian lime seed and some physicochemical properties of its cold-pressed and solvent-extracted oil were investigated. Bulk density, true density, angle of repose, thousand seed mass, and coefficients of static friction were higher in fresh seeds than in dried seeds, but porosity was lower (p 0.05). Cold pressing resulted in a significantly lower oil extraction yield (34.4%), as compared to the solvent extraction (44.2%). Cold-pressed oil showed lower free fatty acid content, peroxide value, color L, a*, b* parameters, total carotenoids, iodine value, and sterol content, and higher phenolics, alpha-tocopherol contents, and oil stability index (p 0.05). Both oil samples contained similar amounts of chlorophyll and unsaponifiable matter (p 0.05). The major fatty acids of cold-pressed Persian lime seed oil were linoleic (30.72%), palmitic (27.09%), oleic (26.06%) and linolenic acids (6.98%). The oil was mainly composed of PLO (18.15%), PLL (16.12%), PPL (9.87%), POO (8.87%), LLO (6.95%), PPO (5.67%), LLL (3.76%), OOO (5.86%), and PLLn (5.26%) triacylglycerols (TAG). The cold-pressed oil contained slightly lower amounts of palmitic acid, linolenic acid, and PPL and LLL TAGs but slightly higher amounts of oleic acid, linoleic acid, and PLO, PLL and OOO TAGs than the solvent extracted oil (p 0.05). beta-sitosterol, campesterol, and Delta-5 avenasterol were the dominant sterols in both oil samples. Based on the differential scanning calorimetry, the oil started melting at around - 24 degrees C and fully crystallized at around - 8 degrees C.

关键词： Amla seed coat   Physicochemical analysis   Mineral analysis   Antioxidant potential   Antibacterial potential   Antifungal potential  

摘要： In the present study Amla seed coat powder was evaluated for its physicochemical parameters (water retention and water swelling capacity), nutraceutical composition (mineral and phytochemical composition) antioxidant (only DPPH method) and antibacterial [Burkholderia spp. Pseudomonas aeuroginosa (KF853103.3), Klebsiella spp. (KF424316.1)] and antifungal (Fusarium oxysporum) potential. Water retention and water swelling capacity of the amla seed coat powder were found to be 5.841 g/g and 8.96 mL/g of dry weight (DW). Seed coat contained a sufficient amount of minerals. Different extracts of amla seed coat were prepared by four extraction procedures (maceration (MM), orbital shaking (OSM), ultrasonication assisted extraction (UAEM) and Soxhlet extraction method (SEM)) using different solvents (petroleum ether (PEE), isopropyl alcohol (IAE), butanol (BUE), ethyl acetate (EAE) and acetone (AE)). All the extracts were found to contain different phytochemicals. SEM was found to be the best method giving maximum total phenolic and flavonoid content in BUE of amla seed coat with values 12.81 mg gallic acid equivalent (GAE)/g DW and 10.37 quercetin equivalent (QE)/g DW. Further, it has been found that in the antibacterial and antifungal analysis butanol extract has outperformed the results shown by other extracts. Correlation analysis shows positive correlation between total polyphenolic content (TPC), total flavonoid content (TFC) and various studied activities. Graphic abstract

关键词： Freshwater ecosystems   Water quality index   Proteolytic bacteria   Enzymatic activity  

摘要： The enzymatic reactions of microbial communities are rapid and adequate to changes in the composition of organic matter and environmental factors;therefore, they can be used as descriptors of biological responses in freshwater systems. The objective of this work was to determine the proteolytic enzymatic activity in the Almendares and San Juan rivers (western Cuba) and their relationship with physicochemical and microbiological indicators. The Almendares River (Havana, Cuba) presented water quality index between very poor and unusable for consumption, which makes impossible for recreational uses. In contrast, the waters of the San Juan River (Artemisa, Cuba) are classified as excellent and good in most of the sampling stations during the study period. The greatest proteolytic activities were detected in the San Juan River compared to the Almendares River, which indicates that in more contaminated ecosystems, the proteolytic enzyme activity decreases compared to another less impacted system. In addition, the annual variation in the proteolytic activity of both rivers was evidenced. In the San Juan River, a correlation was observed among proteolytic activity, the concentration of proteolytic bacteria and the physicochemical indicators of water quality, suggesting that proteolytic activity is related to naturally occurring contaminants. In contrast, in the Almendares River, this relationship was not observed, which suggests that the proteolytic activity is not directly affected by the indicators measured in this study.

关键词： hydrogels   mechanobiology   T cell activation   immunomodulation   substrate stiffness   immunotherapy  

摘要： The recent rise of adoptive T cell therapy (ATCT) as a promising cancer immunotherapy has triggered increased interest in therapeutic T cell bioprocessing. T cell activation is a critical processing step and is known to be modulated by physical parameters, such as substrate stiffness. Nevertheless, relatively little is known about how biophysical factors regulate immune cells, such as T cells. Understanding how T cell activation is modulated by physical and biochemical cues may offer novel methods to control cell behavior for therapeutic cell processing. Inspired by T cell mechanosensitivity, we developed a multiwell, reusable, customizable, two-dimensional (2D) polyacrylamide (PA) hydrogel-integrated culture device to study the physicochemical stimulation of Jurkat T cells. Substrate stiffness and ligand density were tuned by concentrations of the hydrogel cross-linker and antibody in the coating solution, respectively. We cultured Jurkat T cells on 2D hydrogels of different stiffnesses that presented surface-immobilized stimulatory antibodies against CD3 and CD28 and demonstrated that Jurkat T cells stimulated by stiff hydrogels (50.6 +/- 15.1 kPa) exhibited significantly higher interleukin-2 (IL-2) secretion, but lower proliferation, than those stimulated by softer hydrogels (7.1 +/- 0.4 kPa). In addition, we found that increasing anti-CD3 concentration from 10 to 30 mu g/mL led to a significant increase in IL-2 secretion from cells stimulated on 7.1 +/- 0.4 and 9.3 +/- 2.4 kPa gels. Simultaneous tuning of substrate stiffness and stimulatory ligand density showed that the two parameters synergize (two-way ANOVA interaction effect: p < 0.001) to enhance IL-2 secretion. Our results demonstrate the importance of physical parameters in immune cell stimulation and highlight the potential of designing future immunostimulatory biomaterials that are mechanically tailored to balance stimulatory strength and downstream proliferative capacity of therapeutic T cells.

关键词： Physicochemical properties  

摘要： We present a generic way to hybridize physical and data-driven methods for predicting physicochemical properties. The approach 'distills' the physical method's predictions into a prior model and combines it with sparse experimental data using Bayesian inference. We apply the new approach to predict activity coefficients at infinite dilution and obtain significant improvements compared to the physical and data-driven baselines and established ensemble methods from the machine learning literature.

关键词： Sewage sludge  

摘要： NaCl and (NH4)(2)SO4 were selected as typical inorganic salts (10 wt% addition) in order to analyze their effects on the hydrothermal carbonization (HTC) of sewage sludge (SS). Results indicated that both salts could be adsorbed on the surface of hydrochar, resulting in amounts of hydrochar increasing and potentially serious nitrogen and chlorine issues upon employing SS hydrochar as solid fuel. NaCl and (NH4)(2)SO4 could act as catalyst to promote hydrolysis and carbonization of SS, with (NH4)(2)SO4 participating in the carbonization of SS. During combustion, Cl decreased the thermal decomposition temperature of hydrochar. The reported results can provide information to optimize the use of chloride salts and NH4+ concentration for increasingly efficient HTC processes.

关键词： Hygrothermal   Bio-based materials   TGA   DSC   FTIR   Physicochemical  

摘要： The utilisation of bio-based building materials as hygric buffers has received recent research interest due to their moisture sorption and thermal behaviours which are positive for indoor comfort. Their hygrothermal properties are known but not fully understood, especially when these bio-based materials are exposed to frequent indoor relative humidity (RH) levels. For the first time, it is identified the characteristics at a micro-level responsible for the hygrothermal performance. Bio-based samples utilised within this paper are: Saw Mill Residue (SMR), Wool 1 (W1), Wool 2(W2), Wood Pellets (WP), Straw (STW) and Wood Wool Board (WWB). Results included thermal analysis (DSC, TGA, DTG), chemical analysis (FTIR) and optical microscopy (SEM) to understand and compare how these bio-based materials behave when stabilised at 53% and 75% RH. For cellulose based samples it was demonstrated that in a dynamic hygrothermal environment SMR and WP are the most hygrothermal stable and for keratin-based materials, W1 is the most stable. For the keratin-based samples when conditioned at 75%, as per the intensity of FTIR spectra, the regularity of molecular chain, W2 has the more ordered material structure but W1 is affected more in terms of hydroxyl absorbance from the spectra. These experiments give a greater insight into the dynamic way in which RH affects the thermal stability of samples. This research paper outlines fundamental differences within materials physical properties and chemical reactions. From the 6 different materials that were used, SMR was demonstrated to be the most thermally stable sample overall. (C) 2020 Elsevier Ltd. All rights reserved.