ALBERT

Description: Gut microbiota, a major contributor to human health, is influenced by physical activity and diet, and displays a functional cross-talk with skeletal muscle. Conversely, few data are available on the impact of hypoactivity, although sedentary lifestyles are widespread and associated with negative health and socio-economic impacts. The study aim was to determine the effect of Dry Immersion (DI), a severe hypoactivity model, on the human gut microbiota composition. Stool samples were collected from 14 healthy men before and after 5 days of DI to determine the gut microbiota taxonomic profiles by 16S metagenomic sequencing in strictly controlled dietary conditions. The α and β diversities indices were unchanged. However, the operational taxonomic units associated with the Clostridiales order and the Lachnospiraceae family, belonging to the Firmicutes phylum, were significantly increased after DI. Propionate, a short-chain fatty acid metabolized by skeletal muscle, was significantly reduced in post-DI stool samples. The finding that intestine bacteria are sensitive to hypoactivity raises questions about their impact and role in chronic sedentary lifestyles.

Description: The restoration of paintings always involves the removal of darkened superficial layers, which are mainly due to dust deposition and aged varnishes. As cleaning is an irreversible and invasive treatment, physical methods (i.e., laser cleaning) instead of chemical ones are frequently suggested to reduce side effects on pictorial layers. Among the most employed laser systems, the free-running Er:YAG laser is considered very suitable for fine arts cleaning. This laser works at 2.94 μm, at which only –OH and –NH bonds in molecules are excited. This character can become a disadvantage when pigments with these functional groups are present. To understand the potential of the Er:YAG laser in such situations or in the presence of degradable pigments, the effectiveness of varnish removal from paintings prepared with egg yolk as the binder and cinnabar and lead white as the pigments were systematically investigated. Different cleaning conditions were used, and a hyperspectral sensor was innovatively used as a rapid, in situ and non-destructive technique to assess the effects of laser ablation, besides microscopic analysis. Though results obtained show all these pigments are sensitive to this laser radiation, satisfactory cleaning can be achieved without damaging the pictorial layer. The best cleaning conditions were 0.5 W of power (50 mJ and 10 Hz for energy and frequency), with 2-propanol as the wetting agent.

Description: This paper explores the use of calcareous tuberculosis as an adsorbent and heavy-metal ions (Cu2+, Zn2+, Cd2+, and Pb2+) as adsorbates, and the influence of varying levels of particle size, adsorption time, pH, adsorbent dosage, and initial concentration of heavy metals is studied through an experiment of single heavy-metal adsorption. In addition, the impact of the temperature and other factors on the adsorption of heavy-metal ions by calcareous nodules is analyzed to identify the optimal conditions for the adsorption of heavy-metal ions by calcareous nodules. As shown by the research findings, the adsorption rates of Cu2+, Zn2+, and Pb2+ gradually declined with the increase in particle size, with no evident effect on Cd2+. In the meantime, with further increases in factors such as the adsorption time, adsorbent dosage, and temperature, the adsorption rates of Cu2+, Zn2+, Cd2+, and Pb2+ experienced gradual increases. The adsorption rates of Cu2+, Zn2+, and Cd2+ gradually declined with the increase in initial concentration of heavy-metal ions, whereas the adsorption rate of Pb2+ experience increased first and then declined. As the pH increased, the adsorption rate of Cd2+ experience increased first and then declined at a slow pace. The adsorption rates of Cu2+, Zn2+, and Pb2+ increased first and then decreased. The adsorption capacity of calcareous nodules toward the four heavy-metal ions was in the order of Pb2+ 〉 Zn2+ 〉 Cu2+ 〉 Cd2+. When the particle size was set to 0.25 mm, the adsorption time was set to 120 min, and the dosage was set to 0.6 g, the calcareous nodules included Pb2+, Zn2+, and Cu2+. Moreover, Cd2+ was able to achieve stronger adsorption capacity, with the adsorption rate able to reach 83.33%, 77.78%, 73.81%, and 81.93% of its maximum level. Therefore, as the particle size of the heavy-metal ions decreased, the adsorption capacity generally became stronger. As the adsorption time increased, the temperature and the amount of adsorbent also increased. The optimal pH value for the adsorption of calcareous nodules toward Pb2+, Zn2+, Cu2+, and Cd2+ was found to be 7, 6, 5, and 8, respectively, and the optimal temperature was 50 °C. In summary, calcareous nodules are a natural, low-cost, and effective adsorbent.

Description: We report that polymerization makes a robust, practically applicable multifunctional optical device with a continuous wavelength tunable over 500 nm spectral range using UV-polymerizable cholesteric liquid crystals (CLCs). It can be used as a circular polarizer generating an extremely high degree of circularly polarized light with |g| = 1.85~2.00. It can also be used for optical notch filters, bandwidth-variable (from ~28 nm to ~93 nm) bandpass filters, mirrors, and intensity-variable beam splitters. Furthermore, this CLC device shows excellent stability owing to the polymerization of CLC cells. Its performance remains constant for a long time (~2 years) after a high-temperature exposure (170 °C for 1 h) and an extremely high laser beam intensity exposure (~143 W/cm2 of CW 532 nm diode laser and ~2.98 MW/cm2 of Nd: YAG pulse laser operation for two hours, respectively). The optical properties of polymerized CLC were theoretically analyzed by Berreman’s 4 × 4 matrix method. The characteristics of this device were significantly improved by introducing an anti-reflection layer on the device. This wavelength-tunable and multifunctional device could dramatically increase optical research efficiency in various spectroscopic works. It could be applied to many instruments using visible and near-infrared wavelengths.

Description: Over the last years, the replacement of traditional polymer modifiers with waste plastics has attracted increasing interest. The implementation of such technology would allow a drastic reduction of both production cost and landfill disposal of wastes. Among all, polyethylene-based plastics have been proved suitable for this purpose. The research activities presented in this paper aim to assess the synergistic effect of polyethylene and Fischer–Tropsch waxes on the viscoelastic properties and performance of the bitumen. In order to reduce the blending time, waxes, and polyethylene need to be added simultaneously. In fact, the presence of the waxes reduces the polarity of the bitumen matrix and increases the affinity with the polymer promoting its dispersion. Results demonstrate that the chain length of the waxes, the form of the added waste polyethylene, and the blending protocol have critical effects on the time-evolution of such properties. Short-chain waxes have a detrimental impact on the rutting resistance regardless of the blending protocol. On the contrary, long-chain waxes improve the overall behavior of the polyethylene-modified binders and, in particular, the resistance to permanent deformations.

Description: Over the last few years, there has been a growing interest in the study of lightweight composite materials. Due to their tailorable properties and unique characteristics (high strength, flexibility and stiffness), glass (GFs) and carbon (CFs) fibers are widely used in the production of advanced polymer matrix composites. Glass Fiber-Reinforced Polymer (GFRP) and Carbon Fiber-Reinforced Polymer (CFRP) composites have been developed by different fabrication methods and are extensively used for diverse engineering applications. A considerable amount of research papers have been published on GFRP and CFRP composites, but most of them focused on particular aspects. Therefore, in this review paper, a detailed classification of the existing types of GFs and CFs, highlighting their basic properties, is presented. Further, the oldest to the newest manufacturing techniques of GFRP and CFRP composites have been collected and described in detail. Furthermore, advantages, limitations and future trends of manufacturing methodologies are emphasized. The main properties (mechanical, vibrational, environmental, tribological and thermal) of GFRP and CFRP composites were summarized and documented with results from the literature. Finally, applications and future research directions of FRP composites are addressed. The database presented herein enables a comprehensive understanding of the GFRP and CFRP composites’ behavior and it can serve as a basis for developing models for predicting their behavior.

Description: The liver-derived hormone fibroblast growth factor 21 (FGF21) has recently been linked to preference for sweet-tasting food. We hypothesized, that surgery-induced changes in FGF21 could mediate the reduction in sweet food intake and preference following bariatric surgery. Forty participants (35 females) with severe obesity (BMI ≥ 35 kg/m2) scheduled for roux-en-y gastric bypass (n = 30) or sleeve gastrectomy (n = 10) were included. Pre- and postprandial responses of intact plasma FGF21 as well as intake of sweet-tasting food assessed at a buffet meal test, the hedonic evaluation of sweet taste assessed using an apple juice with added sucrose and visual analog scales, and sweet taste sensitivity were assessed before and 6 months after bariatric surgery. In a cross-sectional analysis pre-surgery, pre- and postprandial intact FGF21 levels were negatively associated with the hedonic evaluation of a high-sucrose juice sample (p = 0.03 and p = 0.02). However, no changes in pre- (p = 0.24) or postprandial intact FGF21 levels were found 6 months after surgery (p = 0.11), and individual pre- to postoperative changes in pre- and postprandial intact FGF21 levels were not found to be associated with changes in intake of sweet foods, the hedonic evaluation of sweet taste or sweet taste sensitivity (all p ≥ 0.10). In conclusion, we were not able to show an effect of bariatric surgery on circulating FGF21, and individual postoperative changes in FGF21 were not found to mediate an effect of surgery on sweet food intake and preference.

Description: The deformation behavior of semi-crystalline polymers is strongly dependent on the morphology formed during processing. In this study, in-situ synchrotron X-ray was firstly used to identify the morphological distributions of injection-molded isotactic polypropylene (iPP) with different concentrations of β-nucleating agent. It was found that under relatively high concentration of β-nucleating agent (i.e., ≥0.03 wt.%), the outer region (skin and shear region) of the iPP was dominated by mainly highly oriented α-phase as well as certain amount γ-phase, while the core region was rich in β-crystals with little if any orientation. The addition of the β-nucleating agent was beneficial for the formation of lamellae with large lamellar stacking distance in the shear layer. Then the synchrotron X-ray was applied to study the structure variation of those morphology-identified samples under tensile deformation. It was found that voids and cavities along the stretching direction existed in the deformed iPP samples and their volume increased with increasing concentration of β-nucleating agent. The increased volume of void and cavity was associated with the β to α phase transition, which mainly occurred at the core region. In addition, upon stretching crystalline fragmentation and rearrangement took place following the formation of thinner lamellae.

Description: Edible films prepared from biological materials are being massively used. This study aimed to prepare edible films from native potato starch of the Allcca sipas variety (Solanum tuberosum subsp. Andigena), nopal mucilage (Opuntia ficus indica), and glycerol. Twelve edible films were prepared with starch, mucilage, and glycerin in different proportions by thermosynthesis. It was observed that mucilage and glycerol have a significant direct effect on film solubility and an inverse effect on aw, while the effect of starch is the opposite. The aw ranged from 0.562 to 0.639. The FTIR analysis showed the interaction of the components in the films being considerably influenced by the addition of mucilage. The TGA/DTA analysis reported low thermal stability in the films, retaining water around 100 °C, and showing a tendency to lose weight when the content of starch is high, while the opposite occurred with the addition of mucilage; it was also observed that around 310 °C, the maximum weight loss was observed between 53.6 and 86.1%. SEM images showed uniform films without cracks. The results are promising and show the possibility of preparing edible films from native potato starch and mucilage.

Description: We used time-restricted feeding (TRF) to investigate whether microbial metabolites and the hunger hormone ghrelin can become the dominant entraining factor during chronic jetlag to prevent disruption of the master and peripheral clocks, in order to promote health. Therefore, hypothalamic clock gene and Agrp/Npy mRNA expression were measured in mice that were either chronically jetlagged and fed ad libitum, jetlagged and fed a TRF diet, or not jetlagged and fed a TRF diet. Fecal short-chain fatty acid (SCFA) concentrations, plasma ghrelin and corticosterone levels, and colonic clock gene mRNA expression were measured. Preventing the disruption of the food intake pattern during chronic jetlag using TRF restored the rhythmicity in hypothalamic clock gene mRNA expression of Reverbα but not of Arntl. TRF countered the changes in plasma ghrelin levels and in hypothalamic Npy mRNA expression induced by chronic jetlag, thereby reestablishing the food intake pattern. Increase in body mass induced by chronic jetlag was prevented. Alterations in diurnal fluctuations in fecal SCFAs during chronic jetlag were prevented thereby re-entraining the rhythmic expression of peripheral clock genes. In conclusion, TRF during chronodisruption re-entrains the rhythms in clock gene expression and signals from the gut that regulate food intake to normalize body homeostasis.