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关键词： Chemical analysis  

摘要： Photoelectron spectroscopy has long been a powerful method in the toolbox of experimental physical chemistry and molecular physics. Recent improvements in coincidence methods, charged-particle imaging, and electron energy resolution have greatly expanded the variety of environments in which photoelectron spectroscopy can be applied, as well as the range of questions that can now be addressed. In this Perspectives Article, we focus on selected recent studies that highlight these advances and research areas. The topics include reactive intermediates and new thermochemical data, high-resolution comparisons of experiment and theory using methods based on pulsed-field ionisation (PFI), and the application of photoelectron spectroscopy as an analytical tool to monitor chemical reactions in complex environments, like model flames, catalytic or high-temperature reactors.

关键词： Fatty acids  

摘要： In this study, the effect of hydrocolloids with different electrostatic characteristics, namely negatively charged xanthan gum (XG), positively charged chitosan (CH), and non-ionic guar gum (GG), on the physicochemical properties, stability, and lipid digestibility of 10% (w/w) soybean oil-in-water Pickering emulsions stabilized by nanofibrillated cellulose (NFC) was investigated. Addition of XG and CH to the NFC-stabilized emulsions significantly increased the oil droplet sizes and apparent viscosity at high shear rates as compared with the addition of GG. The XG added emulsion showed the lowest rate and extent of creaming, whereas the CH added emulsion gave the highest extent of creaming. The addition of XG and CH led to a more pronounced effect on in vitro lipid digestion, i.e. changes in droplet sizes, surface charges, microstructure, and free fatty acid (FFA) release, than the addition of GG. The XG added emulsion showed the lowest rate and extent of lipid digestion possibly due to the high viscosity of the aqueous phase, large oil droplet sizes, and interaction of XG and calcium, resulting in the reduction of lipase activity. The CH added emulsion exhibited the highest extent of lipid digestion possibly due to binding between CH and FFAs and move away from the droplet surfaces, thereby facilitating the lipase activity. In summary, it can be concluded that ionic hydrocolloids exerted more influence on NFC-stabilized Pickering emulsions than non-ionic ones. These results may facilitate the design of highly stable emulsion-based functional food products with added hydrocolloids to promote health and wellness.

关键词： Physical chemistry   Computational chemistry   Machine learning   Software   Lasers  

关键词： Poly(amidoamine)   Nanotechnology   Molecular weight   PFG-DOSY NMR   Orthogonal polydispersity index  

摘要： The recently developed One-Step Poly(amidoamine) (OS-PAMAM) dendrimers stand out for their characteristics as the high drug-load capacity and cell-delivery improvement of therapeutic agents. The OS-PAMAM dendrimers have proven to be useful in the biomedical field as nanocarrier or nanosystems for therapy. In the present research it was encouraging to determine their physicochemical characteristics which were compared with commercial PAMAM generation-6 (G6). The spectroscopic measurement of amides, nanoparticle size (10-30 nm), polydispersity index and zeta potential measurements correlates with the commercial product. The OS PAMAM has cavities detected by AFM, and the force analysis showed the same adhesion force and different elasticity than PAMAM-G6. The molecular weight (MW) was 10 times lower than the commercial one for both techniques employed, resembling the MW of a PAMAM generation-3 (G3). OS-PAMAM/PAMAM-G6 MS-MS mirror plots demonstrate chemical equivalency amongst herein analyzed dendrimers, with the advantage that OS-PAMAM is produced with a faster and low-cost synthetic protocol, which allows them to be applied for both research and industry in the biomedical field.

关键词： Molecular dynamics  

摘要： The emergence of cocrystals as alternative solid forms for development of novel drug products signifies the relevance of polymorphism studies in cocrystals. We report two novel polymorphs of the cocrystal involving an anti-inflammatory and antioxidative active ingredient, phloretin (PHL), and a pharmaceutically acceptable coformer, nicotinamide (NA). The two polymorphs were structurally characterized. In addition, all the polymorphs and their polymorphic phase transformation were investigated by thermal, slurry and solubility measurements. Form I was identified as the most stable polymorph under ambient conditions. The three polymorphs showed distinct photoluminescence which was rationalized on the basis of pi MIDLINE HORIZONTAL ELLIPSIS pi interactions in their crystal structures. Form I was found to show a higher apparent solubility and dissolution rate which was rationalized on the basis of parameters deduced from molecular dynamics (MD) simulations. The polymorphs of the PHL-NA cocrystal emphasized the impact of polymorphism on the physicochemical properties of cocrystals.

关键词： Size exclusion chromatography  

摘要： Advances in gene-editing technology enable efficient, targeted ex vivo engineering of different cell types, which offer a potential therapeutic platform for most challenging disease areas. CRISPR-Cas9 is a widely used gene-editing tool in therapeutic applications. The quality of gene-editing reagents (i.e., Cas9 nuclease, single guide (sg)RNA) is associated with the final cellular product quality as they can impact the gene-editing accuracy and efficiency. To assess the impact of the quality of Cas9 protein and sgRNA in the formation of a Cas9 ribonucleoprotein (RNP) complex, stability, and functional activities, we developed a size exclusion chromatography method that utilizes multiple detectors and an in vitro DNA cleavage assay using anion-exchange chromatography. Using these methods, we characterized the formation and stability of Cas9 RNP complexes associated with Cas9 and sgRNA characteristics as well as their functional activities. Multi-angle light scattering characterization showed different types and levels of aggregates in different source sgRNA materials, which contribute to form different Cas9 RNP complexes. The aggregations irreversibly dissociated at high temperatures. When the Cas9 RNP complexes derived from non-heated and heated sgRNAs were characterized, the data showed that specific RNP peaks were impacted. The Cas9 RNP complexes derived from the heated sgRNA retained their biological function and cleaved the double-strand target DNA at a higher rate. This work provides new tools to characterize the Cas9 RNP complex formation, stability, and functional activity and provides insights into sgRNA properties and handling procedures to better control the Cas9 RNP complex formation.

关键词： Honey   mineral elements   north Algeria   physico-chemical properties  

摘要： Honey is accepted as food and medicine by all generations both ancient and modern. In this study the concentrations of K, Mg, Na, Zn, Fe, Mn, Cu, Cr, Ni, Se, As, Pb, Cd, Sb, Ti, V, Co, Hg and the determination of some physico-chemical parameters in 29 multifloral honeys collected from different North regions of Algeria: Algiers, Bouria, Ghardaia, Laghouat, M'sila, Naama, Tlemcen and El Bayadth during year 2018 were carried out. All minerals were determined by ICP-OES/MS and Hg by DMA-80. The most abundant minerals decreased in the following order: K, Na, Mg, Fe, Zn. Lead content exceeded the Codex Alimentarius and the European Union in all honey samples analysed, Cd and As levels were lower than the limits fixed by the European legislation and the regulations of the Codex Alimentarius. The Recommended Dietary Allowance values and benchmark levels were employed to assess the honey quality and safety.

关键词： Long-chain inulin   Ultrasound   Rheological properties   Structure  

摘要： In this study, ultrasound was employed to radiate long-chain inulin suspensions in order to obtain some new physicochemical properties. The results showed that ultrasound irradiation effectively improved the viscoelasticity of long-chain inulin samples. The samples achieved the greatest increase in the apparent viscosity and viscoelasticity after 10-min ultrasonic treatment at the intensity of 1734.9 W/cm2. In addition, Fourier transform infrared spectroscopy (FTIR) spectrum analysis revealed that ultrasound could not change the functional groups and molecular structure of long-chain inulin, only effect the hydrogen bonds of long-chain inulin. The results of X-ray diffraction (XRD) indicated that ultrasound also affected the relative crystallinity of long-chain inulin, depending on its intensity and treatment time. Particle size distribution indicated that long-chain inulin with particle size of 100-300 mu m formed after ultrasound treatment. The changes in inulin particle size showed that inulin was unfolded by ultrasound treatment at low intensity for a short time and then aggregated with enhanced ultrasound effect. These results suggested that ultrasound treatment can change the physicochemical and structural properties of long-chain inulin, which would facilitate long-chain inulin application in the food industry.

关键词： Alternative protein   Protein recovery   Essential amino acids   Emulsion properties   Protein solubility  

摘要： This study aimed to produce protein hydrolysates from sesame bran using ultrasound-assisted enzymatic extraction followed by spray-drying (SD) and freeze-drying (FD) techniques. Spray drying parameters highly influenced powder yield (22.8-70.5%), protein yield (23.0-70.4%), drying time (41-149 min) and a(w) value (0.196-0.288). Therefore, the impacts of SD and FD were assessed after an optimization study. Drying techniques significantly affected amino acid, mineral and lignan compositions as well as proximate powder properties. FD revealed significantly improved wettability (2.3 s) and dispersibility (98.6%) values with higher foaming capacity (35%). Protein powders produced by FD had considerably lower bulk and tapped densities which are important parameters for processing and transportation. On the other hand, SD provided higher water holding capacity (0.94 g H2O/g protein) and better color properties (L*: 71.4). The newly developed protein powder as a functional ingredient could offer sustainable options to food industry and may open up new opportunities to be used in various food formulations.

关键词： honey   monofloral honeys   physicochemical parameters   multivariate analysis   principal component analysis (PCA)   multi-discriminant analysis (MDA)  

摘要： BACKGROUND Although the main method for authentication of monofloral honey is pollen analysis, other classification approaches have been also applied. However, the majority of the existing classification models so far have utilized a few honey types or a few honey samples of each honey type, which can lead to inaccurate results. Aiming at addressing this, the goal of the present study was to create a classification model by analysing in total 250 honey samples from 15 different monofloral honey types in ten physicochemical parameters and then, multivariate analysis [multivariate analysis of variance (MANOVA), principal component analysis (PCA) and multi-discriminant analysis (MDA)] was applied in an effort to distinguish and classify them. RESULTS Electrical conductivity and colour were found to have the highest discriminative power, allowing the classification of monofloral honey types, such as oak, knotgrass and chestnut honey, as well as the differentiation between honeydew and nectar honeys. The classification model had a high predictive power, as the 84.4% of the group cases was correctly classified, while for the cases of chestnut, strawberry tree and sunflower honeys the respective prediction was correct by 91.3%, 95% and 100%, allowing further determination of unknown honey samples. CONCLUSION It seems that the characterization of monofloral honeys based on their physicochemical parameters through the proposed model can be achieved and further applied on other honey types. The results could contribute to the development of methodologies for the determination of honey's botanical origin, based on simple techniques, so that these can be applied for routine analysis. (c) 2021 Society of Chemical Industry.