Propolis, a complex bee product, is a source of numerous bioactive principles, beneficial for human health, therefore it is intensively studied. In the present work, extracts of propolis from Bihor ...Romanian County were studied to identify the relationship between the polyphenolic derivatives profile and their antioxidant and antimicrobial activity. Extracts were obtained using water and 25%, 50%, and 70% ethanolic solutions (w/w), at 2:1, 4:1, and 6:1 liquid: solid ratios (w/w). 21 polyphenolic derivatives were quantified by UHPLC-MS, proving that the extracts composition strongly depends on the solvent. The sum of quantified polyphenolics extracted varied between 1.5 and 91.2 mg/g propolis. The antioxidant capacity was evaluated using the free radicals 2,2'-azino-bis (3-ethylbenzothiazoline-6 sulfonic acid) diammonium salt (ABTS) and 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging methods. Antimicrobial efficiency was tested against Gram-positive (B. subtilis), Gram-negative bacteria (E. coli), and fungi (C. albicans) by disc-diffusion method. All extracts, even the aqueous ones, demonstrated antibacterial and antifungal activity. Chemometric methods (partial least squares) and a saturation-type model were used to evaluate the contribution of various bioactive principles in building the antioxidant capacity of extracts. Both experimental and modelling results show that 50% ethanolic extracts provide a rich polyphenolics profile and ensure a good antioxidant capacity.
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•A hybrid US and MW reactor is reported.•The system uses monomode MW and US convertors operating at different frequencies.•Continuously high-power densities can be used with fully ...controlled temperature.•Transesterification of vegetable oil was used as a model for process intensification.
Ultrasound (US) and Microwaves (MW) are effective methods for processes intensification. Their combined use in the same reactor can lead to remarkable results. Recently there has been a resurgence of interest in this field for new synthetic applications using reactors based upon existing technologies. We describe here a new type of apparatus in which the thermal energy is continuously removed from the system making possible the use of high power and adjustable ultrasonic and microwave densities throughout the process. The installation consists of a glass reactor located in a monomode applicator which is immersed at the same time in an ultrasonic device which can be operated at different frequencies and powers. A liquid, transparent to microwaves, was used to couple ultrasonic energy to the reactor and to remove the heat generated. Comsol software was used to get information about the distribution of ultrasonic and microwave energy between the reactor liquid and the coupling fluid. The performance was assessed using the conversion of p-nitrophenol into 4-nitrocatechol as a chemical dosimeter and a transesterification.
This research study deals with lead(II)/Pb2+ removal from aqueous solutions by calcium alginate (CA) and chitosan coated calcium alginate (CCCA) as adsorbents, in batch experiments. A simple ...synthesis method was used to prepare both adsorbent materials. CA and CCCA were characterized using infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetric analysis (TG).
The main parameters determining the quantity of lead(II) ions adsorbed are: the initial pH solution, the lead(II)ions initial concentration and the temperature. The experiments revealed that the adsorption capacity, thus, the removal efficiency are higher for CCCA compared to CA.
The adsorption of lead(II) ions onto both CA and CCCA materials is an endothermic spontaneous process, as resulted from the thermodynamic experiments. Consequently, a moderate increase of temperature improves the adsorption capacity.
The thermodynamic equilibrium sorption experimental data are well fitted by Freundlich adsorption isotherm for both tested adsorbents, better than Langmuir's. Accordingly, lead(II) ions adsorption onto CA and CCCA develops obeying a multilayer mechanism.
The kinetic experimental data were fitted by both pseudo-first, and pseudo-second order models. The former approaches better the experimental results for both adsorbents.
The mechanism involved in lead removal is a combination between ion-exchange and coordination/chelation based on experimental results.
•UAE changes polyphenolic acids and flavonoids profiles compared to maceration.•Solvent is the key operational parameter setting up extracted polyphenolics profile.•50% ethanol & UAE boost yield, ...antioxidant capacity and antimicrobial activity.
Ultrasound-assisted extraction (UAE) was applied for polyphenols extraction from Romanian propolis, followed by comparison with previous maceration work. The effects consisted not only in time reduction and extraction yield increase, but also in polyphenolics profile modification in terms of flavonoids / polyphenolic acids ratio. The operating parameters were ultrasounds (US) field exposure time (10–100 min), solvent composition (water, 25 % and 50 % ethanolic solutions, w/w), and liquid:solid ratio (2:1, 4:1 and 6:1, w:w), while keeping temperature constant. 24 polyphenolic derivatives were quantified by UHPLC-HRMS. UAE favored the extraction of pinocembrin, isorhamnetin and chrysin in water and 25 % ethanol, leading to different profiles than maceration, and further influences upon the antioxidant and antimicrobial activity. All extracts demonstrated increased antibacterial and antifungal activity compared to maceration, particularly the 50 % ethanolic extracts, which presented a three-times larger antioxidant capacity. Chemometric methods (Principal Component Analysis – PCA and Partial Least Squares Regression – PLS) and a saturation type model were used to correlate the polyphenolics profiles and antioxidant capacity. Experimental and modelling results concluded that 50 % ethanolic solutions and UAE represent the favorable operating conditions in terms of yield and extracts quality.
Recent advances and large-scale use of hybrid imaging modalities like PET-CT have led to the necessity of improving nano-drug carriers that can facilitate both functional and metabolic screening in ...nuclear medicine applications. In this study, we focused on the evaluation of four potential imaging nanoparticle structures labelled with the
Ga positron emitter. For this purpose, we functionalized NHS-activated PEG-gold nanoparticles with
Ga-DOTA-Neuromedin B,
Ga-DOTA-PEG(4)-BBN(7-14),
Ga-DOTA-NT and
Ga-DOTA-Neuromedin N. In vitro binding kinetics and specific binding to human HT-29 colon carcinoma cells and DU-145 prostate carcinoma cells respectively were assessed, over 75% retention being obtained in the case of
Ga-DOTA-PEG(4)-BBN(7-14)-AuNP in prostate tumour cells and over 50% in colon carcinoma cells. Biodistribution in NU/J mice highlighted a three-fold uptake increase in tumours at 30 min post-injection of
Ga-DOTA-NT-AuNP and
Ga-DOTA-PEG(4)-BBN(7-14)-AuNP compared to
Ga-DOTA-NT and
Ga-DOTA-PEG(4)-BBN(7-14) respectively, therewith fast distribution in prostate and colon tumours and minimum accumulation in non-targeted tissues.
Oak bark is a by-product known for its richness in polyphenols, with tanning substances being particularly interesting for their application in different fields. Vegetable tannins are mostly utilized ...in the leather sector, but are also widely used as adhesives, in cement plasticizers and for medical and agrochemical applications owing to their natural antimicrobial activity. This study aimed to develop a green and efficient pilot-scale technique for extracting polyphenols from oak bark by ultrasound-assisted extraction (UAE) using a modified Dual-Frequency Reactor (DFR). Different parameters, such as extraction time, temperature, and solvent type (water, sodium hydroxide or sodium sulfite and bisulfite solutions) were investigated for their influence on the total phenolic content (TPC) and the quantity of dry extract. Control experiments by conventional methods were also performed. UAE at 50 °C yielded the highest TPC and dry extract (confirmed by ANOVA analysis, p < 0.05) in just 10 min, suggesting that UAE can be considered an energy- and cost-effective alternative to conventional techniques. The most suitable solvent was found to be a 0.5% sodium hydroxide solution. The molecular profile of the extracts was assessed by FTIR-ATR spectroscopy, revealing typical signals of tannins in all extracts. Furthermore, antimicrobial activity tests demonstrated the complete absence of Gram-positive and Gram-negative bacteria in the extracts, ensuring the suitability of the product for different kinds of application.
Although its high protein content, bioactive compounds, and dietary fibers have many health benefits, lupine (Lupinus sp.) was undervalued as a resourceful plant. In the last years, however, the ...number of studies on the use of lupine as a potential food ingredient has increased. In this study, obtaining a sweet lupine protein concentrate (SLPC) hydrolysate with a high degree of hydrolysis (DH) and a simultaneous low intensity of bitterness was pursued. The experimental design was carried out, according to Taguchi methodology, using three experimental parameters: enzyme concentration (0.5–1.5%), temperature (50–60 °C), and time (1–4 h), with three levels each. The optimal conditions for the enzymatic hydrolysis process of SLPC with Alcalase 2.4 L were enzyme concentration 1.5%, temperature 50 °C, and time 4 h, for which the best DH, 41.96%, was achieved. The SLPC hydrolysate as a food ingredient was characterized in terms of DH, bitter taste intensity, amino acid profile, and techno-functional properties. The results showed an increase of water binding capacity to 1.45 g/g, emulsification activity of 50.91%, and 92% stability of the emulsion, while the evaluated intensity of bitterness was 4.6 on a 7- point scale. Based on its technological, functional, sensory, and chemical characteristics, this study recommends the use of SLPC hydrolysate as a food ingredient in various food matrices.
The removal of sulfur and nitrogen oxides from flue gases using high energy electron beams is based on the generation of excited molecules when the flue gas is bombarded by accelerated electrons. The ...excited molecules undergo ionization, dissociation and electron attachment to yield reactive species (ions, metastables, free radicals and electrons) which interact with the flue gas components. A complex mathematical model was built-up, which includes the main chemical processes in both gas and liquid phases together with the droplets generation and thermodynamic equilibrium between the two phases. The simulation results are in good agreement with the experimental data gathered from literature. Modeling the formation of liquid droplets and the adjacent physico-chemical phenomena provide a better understanding of the process and a more accurate interpretation of the experimental results. The model enables the investigation of the treatment efficiency's sensitivity upon the main operating parameters. A fractional three level factorial white experiment was designed using as parameters the irradiation dose, the water vapor content and the nitrogen oxide initial concentration of the flue gases. The removal yield of SO2 is rather insensitive to the said parameters, while, on the contrary, the removal yield of NO is very sensitive.
•A mathematical model for the electron beam flue gas treatment was developed.•The main chemical processes in both gas and liquid phases are accounted for.•The droplet generation and adsorption of gas components are taken in consideration.•The model is in good agreement with the experimental data in bibliographical sources.•The sensitivity of the process was tested using a fractional factorial white experiment.
► Simultaneous water/wastewater and treatment networks optimization as two subsystems linked by external recycles. ► Concomitant freshwater consumption and costs minimization revealing the degeneracy ...of the integrated network. ► Optimal topology depends upon the ordering criterion of the WU and treatment subsystems, with respect to operating conditions. ► Local and overall mean availability analysis pointing out the critical contaminants and bottleneck islands. ► Pareto front revealing equally optimal solutions of internal/external flows accommodating the same pipe network topology.
The dual-objective optimization of an integrated water/wastewater network (IWWN) is addressed by targeting for minimum fresh water consumption at the same time with operating costs reduction. An IWWN is a recycle system composed of two oriented graphs, the first encoding the water-using units (WUs) and the second, the treatment units (TUs). Although internal recycles are forbidden
ab initio for the WUs graph, external recycles from the appropriate TU to the WU whose inlet restrictions are met by the partially treated water are encouraged. The corresponding mathematical model was written. A synthetic example is proposed and analyzed under several scenarios with respect to the fresh water consumption, the magnitude of internal and treated water reuse and the investment/operating costs related to the active pipes network. A comparison is made regarding the differences in network topology and fresh water consumption implied by different points from the Pareto front (PF).
In recent years, significant attention has been dedicated to converting biomass carbohydrates into alkyl levulinates (biofuel additives) in alcoholic media, in search of various cheap and active ...solid catalysts through relatively easy pathways and from non-dangerous precursors. The synthesis of methyl levulinate (ML) using a new Brønsted/Lewis acid sites catalyst was investigated, emphasizing the influence of three parameters (catalyst loading, the molar concentration of fructose in methanol, and reaction temperature) on the process. The synthetized catalyst, SO42−/TiO2–La2O3 coating Fe3O4, was characterized by different techniques (FT-IR, XRD, TGA, TEM-EDX, ICP-OES). The design of the ML synthesis experiment was carried out using the Box-Behnken technique, while the response surface methodology was applied to obtain the optimized process conditions. A mathematical model of the catalytic synthesis was built, based upon first principles, and the experimental time variation of the reaction mixture concentrations was used to find, through regression, the values of the constants of a newly proposed kinetic model.
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