Optimization of Bioactive Phenolics Extraction and Cosmeceutical Activity of Eco-Friendly Polypropylene-Glycol–Lactic-Acid-Based Extracts of Olive Leaf

Olive leaf is a rich source of phenolic compounds with numerous activities related to skin health and appearance. In this study, a green extraction method was developed using eco-friendly solvents: polypropylene glycol (PPG), lactic acid (LA), and water. The optimal extraction conditions were established, including solvent, extraction time, technique (magnetic stirrer vs. ultrasound-assisted extraction), and herbal material/solvent ratio. The composition of the solvent mixture was optimized using a mixture design. The content of phenolic compounds, including oleuropein and verbascoside, was determined using high-performance liquid chromatography (HPLC) and spectrophotometric methods. Using different extraction conditions, three extracts were prepared and their phytochemical compositions and antioxidant and skin-related bioactivities were investigated. The extracts were excellent inhibitors of elastase, collagenase, tyrosinase, and lipoxygenase. The best activity was shown by the extract richest in phenolics and prepared using magnetic-stirrer-assisted extraction for 20 min, with 0.8 g of herbal material extracted in 10 mL of PPG/LA/water mixture (28.6/63.6/7.8, w/w/w), closely followed by the extract prepared using the same extraction conditions but with 0.42 g of herbal material. The investigated PPG/LA/water mixtures contributed to the overall enzyme-inhibitory activity of the extracts. The prepared extracts were appropriate for direct use in cosmetic products, thus saving the time and energy consumption necessary for the evaporation of conventional solvents.

Polydopamine Induced Wettability Switching of Cellulose Nanofibers/n-Dodecanethiol Composite Aerogels

The novel wettability switchable cellulose nanofiber- (CNF-) based aerogel was conveniently prepared by polydopamine mediated composition of CNF and n-dodecanethiol. The wettability of aerogels can be controlled by adjusting the PDA and n-dodecanethiol loading content, which leads to a variation of water contact angle from 0-149°. The PDA was coated on cellulose nanofibers via hydrogen bonds and then n-dodecanethiol was anchored onto the scaffolds by Michael addition reaction, which was revealed by XPS and FTIR spectra. The composite aerogel can selectively absorb a series of oily liquids from the oil/water mixture, with the maximum absorption capacity of 68 g/g. This work presented a facile strategy to prepare wettability switchable CNF-based heterogenous aerogel and exhibited the potential of the composite aerogel for oil/water separation.

Effects of Selenium on the Chlorophylls, Gas Exchange, Antioxidant Activity and Amino Acid Composition of Lettuce Grown under an Aquaponics System

Aquaponics is a sustainable technique that is respectful to the environment, as it reuses products and minimizes the consumption of new materials. The combination of this technique with the foliar application of selenium (as Na2SeO4) could lead to healthier and more sustainable products, which are increasingly requested by consumers. Lettuce (Lactuca sativa L.) plants were grown in an aquaponics system (fish water) as compared with a control (conventional soilless fertigation), and sprayed with different concentrations of selenium (0, 4, 8, and 16 µmol L−1). The results showed a reduction in the dry weight and N content of lettuce plants irrigated with the fish water mixture treatment. However, the application of Se relieved this stress, increasing the photosynthetic rate and ABTS, and reducing the content of chlorophylls, β-carotene, and several of the measured amino acids. The best results were observed with the highest concentration of Se (16 µmol L−1), as an increase in nitrogen content was observed, as shown by a greater weight of the plant. Furthermore, this treatment produced the greatest increase in ABTS and the least reduction in amino acid content. This novel study highlights the possibility of improving the efficiency of N utilization in lettuce by applying foliar selenium in combination with an aquaponics system.

Synthesis and Characterization of High Surface Area Nano Titanium Dioxide

TiO2 and TiO2-Al2O3 nanoparticles were synthesized via sol-gel method using hydrolysis of Titanium tetraisopropoxide (TTIP) with ethanol and water mixture as titania source. TiO2-Al2O3 Nano-composite was successfully synthesized using the sol-gel technique. Tetraisopropoxide and aluminium isopropoxide were used to prepare TiO2-Al2O3. All prepared samples calcination were conducted at different temperature (400 to 700) oC. The synthesized TiO2 and TiO2-Al2O3 nanocomposites were then characterized by XRD, AFM, BET surface area, SEM, XRF. XRD, the analysis showed that the presence of alumina (Al2O3) in the TiO2 has an effect on crystal size, particles size, surface area, and crystal phases; The XRD result revealed that the prepared TiO2 nanoparticles were anatase phase at 400oC, and 500oC, and transformed to rutile from 600oC to 700oC, but after addition of alumina TiO2 was of anatase phase, without any rutile at all calcination temperatures, also, the addition of alumina leads to a significant decrease in the crystal size, particles size, especially at high temperatures while the surface area of pure titanium was increased, and this corresponds to the results of the AFM and SEM. The best-obtained surface area was 355.18 m2/ gm. with 34.98 nm of average particle size at 500oC in comparison with pure nano titanium dioxide

Insight into the Sorption and Activation Energy Phenomenon of Kenaf Shive Sorbents in Crude Oil/Water Mixture

The secondary effect discovery of synthetic sorbents opened another research direction for many field of studies. However, the sorption parameters of lignocellulosic sorbents are rarely reported most importantly, kenaf shive. This paper centered at the sorption behavior of optimized kenaf shive sorbents using Response Surface Methodology (RSM) via surface deposit technique. Five-level Central Composite Design (CCD) experimental matrix was used to analyze the effect of particle sizes (125-1000 µm), stirring time (5-30min) and methyltrimethoxysilane (MTMS) concentration (5-20% v/v) as individual and combined variables process in the developed sorbents. The unmodified shive was compared with the modified, and it reveals a positive shift in the sorption capability. Instrumental analysis such as FTIR (Fourier Transform Infra-Red), DT-TGA (Differential Thermal-Thermogravimetric analysis) and BET (Brunaure-Emmett-Teller) were carried out on the optimized sorbent and the results were in conformity with the sorption results. The sorption behavior deployed fits the pseudo-first-order and Langmuir isotherm with regression coefficient R2=0.9496 and R2=0.9400. The sorption property was found to be spontaneous and exothermic, however, the activation energy studies shows physic-sorption phenomenon with 25.3 kJmol-1 and R2=0.9360.

Enhancing heat transport in multiphase Rayleigh–Bénard turbulence by changing the plate–liquid contact angles

This numerical study presents a simple but extremely effective way to considerably enhance heat transport in turbulent wall-bounded multiphase flows, namely by using oleophilic walls. As a model system, we pick the Rayleigh–Bénard set-up, filled with an oil–water mixture. For oleophilic walls, using only $10\,\%$ volume fraction of oil in water, we observe a remarkable heat transport enhancement of more than $100\,\%$ as compared to the pure water case. In contrast, for oleophobic walls, the enhancement is only of about $20\,\%$ as compared to pure water. The physical explanation of the heat transport increment for oleophilic walls is that thermal plumes detach from the oil-rich boundary layer and carry the heat with them. In the bulk, the oil–water interface prevents the plumes from mixing with the turbulent water bulk and to diffuse their heat. To confirm this physical picture, we show that the minimum amount of oil necessary to achieve the maximum heat transport is set by the volume fraction of the thermal plumes. Our findings provide guidelines of how to optimize heat transport in wall-bounded thermal turbulence. Moreover, the physical insight of how coherent structures are coupled with one of the phases of a two-phase system has very general applicability for controlling transport properties in other turbulent wall-bounded multiphase flows.

Cyclopentasiloxane (D5) as a Non-Polar Masking Agent for Water-Sensitive Substrates During Polar Solvent Treatment

D5 (decamethylcyclopentasiloxane), a non-polar solvent that evaporates slowly, was tested for its suitability as a temporary masking agent for water-sensitive media on paper objects undergoing aqueous treatment. Three different treatment-related settings were tested on five different paper types, some prepared with water-soluble inks. In 10-min water immersion treatments, D5 proved largely ineffectual in protecting the water-soluble inks. In conjunction with melt-applications of cyclododecane, the addition of D5 enhanced its barrier function only in one case. To test the ability of D5 to prevent tideline formation, the test samples received applications of water, acetone, and a water-ethanol-mixture, creating an interface with freshly D5-impregnated areas. The papers were evaluated visually (VIS, UVA), some after artificial aging. D5 diminished the formation of visible tidelines in the two internally sized papers with low water absorbency in contact with acetone and the ethanol-water mixture, but did not prevent tidelines in contact with water. It also did not protect water-absorbent paper. The results indicate that D5, which is miscible with ethanol and acetone, may disperse tidelines caused by these solvents, but it proved largely insufficient for protecting media during water immersion.

Thermodynamic and Kinetic Description of the Main Effects Related to the Memory Effect during Carbon Dioxide Hydrates Formation in a Confined Environment

This article consists of an experimental description about how the memory effect intervenes on hydrates formation. In particular, carbon dioxide hydrates were formed in a lab–scale apparatus and in presence of demineralized water and a pure quartz porous medium. The same gas-water mixture was used. Half of experiments was carried out in order to ensure that the system retained memory of previous processes, while in the other half, such effect was completely avoided. Experiments were characterized thermodynamically and kinetically. The local conditions, required for hydrates formation, were compared with those of equilibrium. Moreover, the time needed for the process completion and the rate constant trend over time, were defined. The study of these parameters, together with the observation that hydrates formation was quantitatively similar in both types of experiments, allowed to conclude that the memory effect mainly acted as kinetic promoter for carbon dioxide hydrates formation.