Scavenging Efficiency Research Articles

New Perspectives on the Sustainable Employment of Chestnut Shells as Active Ingredient against Oral Mucositis: A First Screening

Oral mucositis (OM), a common side effect of oncological treatment, is an oral mucosal disorder characterized by painful ulcerations and increased risk of infection. The use of natural antioxidants to suppress the redox imbalance responsible for the OM condition has emerged as an interesting approach to prevent/treat OM. This study aims to explore the chestnut (Castana sativa) shells as potential active ingredient against OM. Therefore, chestnut shells were extracted at different temperatures (110-180 °C) by Subcritical Water Extraction (SWE), aiming to recover antioxidants. The extracts were also evaluated against microorganisms present in the oral cavity as well as on human oral cell lines (TR146 and HSC3). The highest phenolic content was obtained with the extraction temperature of 110 °C, exhibiting the best antioxidant/antiradical activities and scavenging efficiencies against HOCl (IC50 = 4.47 μg/mL) and ROO• (0.73 μmol TE/mg DW). High concentrations of phenolic acids (e.g., gallic and protocatechuic acids) and flavanoids (catechin, epicatechin and rutin) characterized the phenolic profile. The antimicrobial activity against several oral microorganisms present in the oral cavity during OM, such as Streptococcus, Staphylococcus, Enterococcus, and Escherichia, was demonstrated. Finally, the effects on HSC3 and TR146 cell lines revealed that the extract prepared at 110 °C had the lowest IC50 (1325.03 and 468.15 µg/mL, respectively). This study highlights the potential effects of chestnut shells on OM.

Experimental study of the impact of scavenging efficiency on diesel combustion in an opposed-piston two-stroke engine

The opposed-piston two-stroke (OP2S) engine is a promising alternative powertrain technology that can offer thermal and brake efficiency improvements over conventional four-stroke engines. In recent years, many of the technical barriers of the OP2S engine architecture have been overcome. However, there is still a need for fundamental studies to provide insight into the scavenging and combustion processes of the OP2S engine to help design and operate the most efficient combustion systems using this engine architecture. This work aims to provide such insights by analyzing experimental data collected on a 3-cylinder, 4.9 L OP2S engine. Specifically, a scavenging efficiency sweep, an engine speed sweep with a constant scavenging efficiency, and an engine speed with a constant pressure differential across the engine were studied in detail. It was found that in diesel combustion, as the scavenging efficiency decreased, the increase in temperature of the hot, internal residuals resulted in a significant increase in heat transfer. Despite lowering pumping losses, this resulted in an overall decrease in brake efficiency. When the bulk thermodynamic conditions of two different scavenging efficiency cases (67% and 72%) were matched at port closing, the lower scavenging efficiency case still displayed a 0.7 percentage point penalty in net thermal efficiency and an increase in engine-out indicated specific emissions of NOx of 18% due to residual stratification in the cylinder. The results presented in this work show that the optimal breathing strategy in diesel combustion on an OP2S engine architecture is one that results in a slightly under-scavenged environment at port closing. However, the results did show potential system-level efficiency benefits of decreasing scavenging efficiency, meaning that alternative fuels and combustion strategies without the constraints of diesel combustion could achieve system-level efficiency gains by running significantly under-scavenged.

Impact of Perfluoropentane Microdroplets Diameter and Concentration on Acoustic Droplet Vaporization Transition Efficiency and Oxygen Scavenging.

Acoustic droplet vaporization is the ultrasound-mediated phase change of liquid droplets into gas microbubbles. Following the phase change, oxygen diffuses from the surrounding fluid into the microbubble. An in vitro model was used to study the effects of droplet diameter, the presence of an ultrasound contrast agent, ultrasound duty cycle, and droplet concentration on the magnitude of oxygen scavenging in oxygenated deionized water. Perfluoropentane droplets were manufactured through a microfluidic approach at nominal diameters of 1, 3, 5, 7, 9, and 12 µm and studied at concentrations varying from 5.1 × 10-5 to 6.3 × 10-3 mL/mL. Droplets were exposed to an ultrasound transduced by an EkoSonicTM catheter (2.35 MHz, 47 W, and duty cycles of 1.70%, 2.34%, or 3.79%). Oxygen scavenging and the total volume of perfluoropentane that phase-transitioned increased with droplet concentration. The ADV transition efficiency decreased with increasing droplet concentration. The increasing duty cycle resulted in statistically significant increases in oxygen scavenging for 1, 3, 5, and 7 µm droplets, although the increase was smaller than when the droplet diameter or concentration were increased. Under the ultrasound conditions tested, droplet diameter and concentration had the greatest impact on the amount of ADV and subsequent oxygen scavenging occurred, which should be considered when using ADV-mediated oxygen scavenging in therapeutic ultrasounds.

Ce (III)-terephthalic acid metal-organic frameworks as highly efficient ·OH radical scavengers for fuel cells and investigation of its antioxidation mechanism

Herein, in order to relieve the chemical degradation of perfluorosulfonic acid (PFSA) membranes without decreasing their proton conductivity, Ce (III)-terephthalic acid metal-organic frameworks (Ce-TPA MOFs) with efficient ·OH radical scavenging efficiency are designed via coordinating the organic antioxidant ligand (TPA) with inorganic radical scavenger (Ce ions). Ce-TPA MOFs with a different weight ratio of 0.5, 1.0, or 2.0% was introduced in PFSA matrix to produce composite membranes. On the one hand, the hydrophilic groups of Ce-TPA MOFs caused better water absorption, which promoted the proton conduction to some extent. Also, the presence of the redox Ce3+/Ce4+ couple, oxygen vacancy, and TPA molecules in Ce-TPA MOFs scavenging ·OH radical together via synergy effect. The optimum peak power density of the PFSA/Ce-TPA1.0 composite membrane at 75 °C under 80% relative humidity was 1086 mW/cm that of pristine PFSA membrane was only 1032 mW/cm. Furthermore, PFSA/Ce-TPA1.0 composite membrane experienced the decay of only 0.31 mV/h during 96 h operation under the same conditions, whereas that of pristine PFSA membrane was 2.20 mV/h. Thus, the PFSA/Ce-TPA membrane was a potential candidate for proton exchange membrane fuel cells.

Aux/IAA11 Is Required for UV-AB Tolerance and Auxin Sensing in Arabidopsis thaliana

In order to survive, plants have, over the course of their evolution, developed sophisticated acclimation and defense strategies governed by complex molecular and physiological, and cellular and extracellular, signaling pathways. They are also able to respond to various stimuli in the form of tropisms; for example, phototropism or gravitropism. All of these retrograde and anterograde signaling pathways are controlled and regulated by waves of reactive oxygen species (ROS), electrical signals, calcium, and hormones, e.g., auxins. Auxins are key phytohormones involved in the regulation of plant growth and development. Acclimation responses, which include programmed cell death induction, require precise auxin perception. However, our knowledge of these pathways is limited. The Aux/IAA family of transcriptional corepressors inhibits the growth of the plant under stress conditions, in order to maintain the balance between development and acclimation responses. In this work, we demonstrate the Aux/IAA11 involvement in auxin sensing, survival, and acclimation to UV-AB, and in carrying out photosynthesis under inhibitory conditions. The tested iaa11 mutants were more susceptible to UV-AB, photosynthetic electron transport (PET) inhibitor, and synthetic endogenous auxin. Among the tested conditions, Aux/IAA11 was not repressed by excess light stress, exclusively among its phylogenetic clade. Repression of transcription by Aux/IAA11 could be important for the inhibition of ROS formation or efficiency of ROS scavenging. We also hypothesize that the demonstrated differences in the subcellular localization of the two Aux/IAA11 protein variants might indicate their regulation by alternative splicing. Our results suggest that Aux/IAA11 plays a specific role in chloroplast retrograde signaling, since it is not repressed by high (excess) light stress, exclusively among its phylogenetic clade.

A multi-process coupling study of scavenging pressure effect on gas exchange of a linear engine

The linear engine is expected to operate with new gas exchange characteristics due to its unconstrained and adaptive dynamics. This study develops a simulation method that mutually transfers the coupling parameters between the piston motion model, generating model, combustion model, and scavenging model, and it iterates the calculation results of motion, combustion and scavenging for gas exchange predication. Then, the coupling effect of scavenging pressure fluctuation on gas exchange in a two-stroke linear engine is also investigated. The results indicate that unlike conventional engine systems, the linear engine reciprocation and compression ratio both increase first and then decrease with the enhancing scavenging pressure, namely the duration of gas exchange is shortened or prolonged, while the linear engine also provides high in-cylinder gas pressure for gas exchange, but the in-cylinder gas temperature reverses. The intake quality and escape amount of the cylinder both vary in positive correlation with the scavenging pressure, which leads to low trapping efficiency, although it cleans more exhaust. The results also find that high scavenging efficiency and fresh charge trapping efficiency can be obtained synchronously at an appropriately low scavenging pressure environment due to its adaptive motion.

Rainfall characteristics significantly affect the scavenging of water-soluble ions attached to leaves

Precipitation is considered the most effective way to remove particulate matter from the leaves of plants. Changes in rainfall characteristics can affect the scavenging processes of particulate matter from leaves. In order to better understand the dynamics of PM scavenging during rainfall, especially the water-soluble ions components, leaves from the 11 plant species (trees, shrubs, terrestrial herbs, wetland plants) from the Olympic park were sampled and used in indoor experiments. During the experiments, the rainfall intensity was set at 30 mm/h, 45 mm/h, and 60 mm/h, and the duration was divided into 0–20 min, 20–40 min, and 40–60 min. The sampled plant leaves were set in the experiments at 1 m and 3 m height from the ground. Concentrations and compositions of nine water-soluble ions of rainfall samples were analyzed in this experiment. The results revealed that SO42-, Ca2+, and Na+ were the most abundant ionic species removed from the leaves, and NO3- ranked fourth, followed by Cl-, Mg2+ K+, NH4+, and F-. The ions concentration of rainfall samples decreased when the rain intensity increased from 30 to 45 mm/h and when the rain intensity increased to 60 mm/h. The efficiency of scavenging during different rainfall durations depends on the ionic species. Na+, Mg2+, Ca2+, and SO42- concentrations increased with the increase in rainfall duration, whereas those of NH4+, K+, and Cl- decreased. The effect of leaf height on ions concentration of rainfall samples was also different among the ionic species: Na+, Mg2+, Ca2+, NO3-, and F- concentrations were significantly higher at 1 m compared with 3 m. The principal component analysis of ions in rainfall samples revealed two main sources of particulate matter in our study. One is from vehicle exhaust and industrial and agricultural pollution. The other is agricultural combustion and ground dust sources. The results of the above study can provide a basis and theoretical support for the establishment of urban cleaning systems and the prevention of air pollution.

Influence of halloysite nanotubes/microfibrillated cellulose on pine leaves waste based ethylene scavenging composite paper for food packaging applications

Pine leaves and pine cone waste contain substantial lignocellulosic mass, which is the major constituent for making paper-based packaging material. The utilization of plant waste as packaging materials eliminates plastics in packaging and promotes a circular economy. In this study, we have developed ethylene scavenging paper from the waste pine leaves (PL) incorporated with microfibrillated cellulose (MFC) and halloysite nanotubes (Hal). MFC attributes include high mechanical properties and gas barrier ability and biodegradability. Hal is a nano clay that possess ethylene gas scavenging properties of the base matrix thus helping in extending the shelf life of fresh produce. The Hal loading affected the fabricated paper's physical and mechanical properties. Field emission scanning electron micrographs revealed that the paper had a rough surface, which was confirmed by atomic force microscopy. The transmission electron micrographs showed that MFC formed a network-like structure. The contact angle and water vapor transmission rate of neat and 30% Hal were decreased from 64° to 52° and 5.7 × 10−3 to 5.5 × 10−3 g/cm2/day, respectively. The X-ray crystallography showed an increase in crystallinity with the addition of Hal and MFC. 30% Hal loading had shown the highest ethylene scavenging efficiency, 79.4% at 25 °C. The results conclude that PL/MFC/Hal functional paper can be effectively utilized as ethylene scavenging material for active packaging applications.

Empirical Model of Uniflow Scavenging for Ultra-Long-Two-Stroke Marine Diesel Engines

_ Low-speed two-stroke diesel engines are widely employed in the marine industry, especially in tanks, owing to their advantages of fuel economy and reliability. However, with the emerging ultra-long-stroke trend, existing scavenging models, which are based on the configuration of cylinders with short strokes, are no longer applicable. In this study, we investigate the flow field and residual exhaust gas distribution in a cylinder using particle image velocimetry and computational fluid dynamics (CFD) simulations. The result shows a strong Burgers vortex structure upstream of the scavenger flow and dissipates gradually as it moves downstream. Furthermore, the scavenging process comprises three processes according to the detailed CFD analysis: displacement, mixing scavenging, and short circuit. Inspired by the results, a tailored empirical model of ultra-long-stroke uniflow scavenging comprising three sub-models is proposed. Specifically, a logarithmic relationship between the concentration level and scavenging deliver ratio is proposed to describe the mixing scavenging process. Finally, the model was validated against CFD results. The results demonstrate that the discrepancy in the scavenging efficiency curve predicted by this model and CFD is less than 1%, thereby demonstrating model reliability. Introduction Owing to the advantages of a large power range, high thermal efficiency, low fuel consumption rate, and good reliability, marine low-speed engines are widely used to provide power to civil ships (Heywood 1999). The market for low-speed engines is vast and is improving the performance of low-speed engines through research has great economic and environmental significance (Woodyard 2004). To meet the requirements of ship owners for lower fuel consumption and the IMO’s regulation of halving the greenhouse gas emissions of newly built ships, the ultra-long stroke of low-speed engines has become a trend (Lamas & Vidal 2012). With an ultralong stroke, the combustion speed of low-quality fuel oil is slow, and an ultra-long-stroke cylinder can prolong the expansion process, improve the combustion process, and reduce the fuel consumption rate (Fenghua 2014). The ultra-long-stroke diesel engine further creates fuel savings of 3.5–7% based on the original low fuel consumption. Previously, ultra-long strokes could not be achieved, limited by materials and manufacturing processes. However, in recent years, with the advancement of materials and processes, ultra-long strokes have been widely adopted as they have demonstrated superior competitiveness.

Scavenging Capacity of Extracts of Arrabidaea chica Leaves from the Amazonia against ROS and RNS of Physiological and Food Relevance.

Arrabidaea chica, a medicinal plant found in the Amazon rainforest, is a promising source of bioactive compounds which can be used to inhibit oxidative damage in both food and biological systems. In this study, the in vitro scavenging capacity of characterized extracts of A. chica leaves, obtained with green solvents of different polarities [water, ethanol, and ethanol/water (1:1, v/v)] through ultrasound-assisted extraction, was investigated against reactive oxygen (ROS) and nitrogen (RNS) species, namely superoxide anion radicals (O2•−), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), and peroxynitrite anion (ONOO−). The extract obtained with ethanol–water presented about three times more phenolic compound contents (11.8 mg/g) than ethanol and water extracts (3.8 and 3.6 mg/g, respectively), with scutellarein being the major compound (6.76 mg/g). All extracts showed high scavenging efficiency against the tested ROS and RNS, in a concentration-dependent manner with low IC50 values, and the ethanol–water extract was the most effective one. In addition, all the extracts were five times more efficient against ROO• than Trolox. Therefore, the extracts from A. chica leaves exhibited high promising antioxidant potential to be used against oxidative damage in food and physiological systems.

Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry Analysis of Eutectic Bis(2,2-dinitropropyl) Acetal/Formal Degradation Profile: Nontargeted Identification of Antioxidant Derivatives.

In the eutectic mixture of bis(2,2-dinitropropyl) acetal (BDNPA) and bis(2,2-dinitropropyl) formal (BDNPF), also known as nitroplasticizer (NP), n-phenyl-β-naphthylamine (PBNA), an antioxidant, is used to improve the long-term storage of NP. PBNA scavenges nitrogen oxides (e.g., NOx radicals) that are evolved from NP decomposition, hence slowing down the degradation of NP. Yet, little is known about the associated chemical reaction between NP and PBNA. Herein, using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF), we thoroughly characterize nitrated PBNA derivatives with up to five NO2 moieties in terms of retention time, mass verification, fragmentation pattern, and correlation with NP degradation. The propagation of PBNA nitration is found to depend on the temperature and acidity of the NP system and can be utilized as an indirect, yet reliable, means of determining the extent of NP degradation. At low temperatures (<55 °C), we find that the scavenging efficiency of PBNA is nullified when three NO2 moieties are added to PBNA. Hence, the dinitro derivative can be used as a reliable indicator for the onset of hydrolytic NP degradation. At elevated temperatures (≥55 °C) and especially in the dry environment, the trace amount of water in the condensed NP (<700 ppm) is essentially removed, which accelerates the production of reactive species (e.g., HONO, HNO3 and NOx). In return, the increased acidity due to HNO3 formation catalyzes the hydrolysis of NP and PBNA nitro derivatives into 2,2-dinitropropanol (DNPOH) and nitrophenol/dinitrophenol, respectively.

PePYL4 enhances drought tolerance by modulating water-use efficiency and ROS scavenging in Populus.

Drought is one of the major limiting factors in the growth of terrestrial plants. Abscisic acid (ABA) and pyrabactin resistance 1/prabactin resistance-1 like/regulatory components of ABA receptors (PYR/PYL/RCARs) play a key role in response to drought stress. However, the underlying mechanisms of this control remain largely elusive in trees. In this study, PePYL4, a potential ortholog of the PYR/PYL/RCARs gene, was cloned from Populus euphratica. It was localized in the cytoplasm and nucleus, induced by ABA, osmotic and dehydration treatments. To study the potential biological functions of PePYL4, transgenic triploid white poplars (Populus tomentosa 'YiXianCiZhu B38') overexpressing PePYL4 were generated. PePYL4 overexpression significantly increased ABA sensitivity and reduced stomatal aperture. Compared with wild-type plants, transgenic plants had higher water-use efficiency (WUE) and lower transpiration. When exposed to drought stress, PePYL4 overexpression plants maintained higher photosynthetic activity and accumulated more biomass. Moreover, overexpression of PePYL4 improved antioxidant enzyme activity and ascorbate content to accelerate reactive oxygen species scavenging. Meanwhile, upregulation expression of the stress-related genes also contributed to improving the drought tolerance of transgenic plants. In conclusion, our data suggest that PePYL4 is a promising gene target for regulating WUE and drought tolerance in Populus.

Simultaneous enhancement of the thermal oxygen and ultraviolet aging resistance of asphalt by incorporating antioxidant intercalated layered double hydroxide

• Antioxidant 1222 intercalated LDHs (LDHs-1222) was successfully prepared. • LDHs-1222 has good UV shielding and free radical capture properties. • LDHs-1222 has good compatibility with asphalt. • LDHs-1222 enhanced thermal oxygen and UV ageing resistances of asphalt simultaneously. This research aims to enhance the anti-thermal oxygen and anti-ultraviolet aging properties of asphalt binder simultaneously with antioxidant intercalated UV-shielding material. For this purpose, the antioxidant 1222 with excellent thermal oxygen resistance was used to modify UV-shielding material layered double hydroxides (LDHs) to synthesize antioxidant 1222 intercalated LDHs (LDHs-1222). The crystal phase, chemical structure and micro-morphology of LDHs-1222 were characterized. The physical properties, storage stability, rheological properties and aging resistance of LDHs-1222 modified asphalt before and after thermal oxygen and UV aging were also investigated. The results showed that CO 3 2– in LDHs was substituted by phosphate group from antioxidant 1222, indicating the successful intercalation of antioxidant 1222. LDHs-1222 maintained the sheet structure and demonstrated a UV reflectivity of 70% and a radical scavenging efficiency of 84.53%, endowing it with desirable UV shielding property and free radical capture property. The incorporation of LDHs-1222 improved the storage stability of modified asphalt. LDHs-1222 modified asphalt exhibited lower complex modulus aging index, carbonyl index and sulfoxide index than LDHs, antioxidant 1222, and composite anti-ageing agent modified asphalts, indicating superior thermal oxygen ageing and UV aging resistance. 4% LDHs-1222 showed the most significant enhancement effect on anti-aging properties of asphalt.

Porous photothermal antibacterial antioxidant dual–crosslinked cryogel based on hyaluronic acid/ polydopamine for non-compressible hemostasis and infectious wound repair

• A series of antioxidant and photothermal antibacterial dual–crosslinked cryogels was designed. • The cryogels showed stable mechanical property and biocompatibility. • These cryogels rapidly stopped irregularly shaped and non-compressible bleeding. • The cryogels significantly improved the MRSA-infected full-thickness skin defect wound healing. Cryogel dressings with good absorption ability and photothermal antibacterial properties for preventing wound infections and treating infected wounds have attracted widespread attention. In this work, a series of cryogels with macroporous structure, antioxidant and photothermal properties were prepared based on adipic dihydrazide modified hyaluronic acid (HA-ADH), and dopamine (DA). The antioxidant properties, hemostatic properties, near infrared (NIR) assisted photothermal antibacterial ability provided by polydopamine, recyclable compression mechanical properties, and cytocompatibility were tested. The results demonstrated that the HA-ADH/DA cryogels have stable mechanical properties, great antibacterial properties against E. coli (EC) and methicillin-resistant S. aureus (MRSA). The high swelling ratio due to the high water retention of HA equipped the cryogels with the capability of absorbing exuded blood and excessive tissue fluid in the infected full-thickness skin defect model of mouse. The cryogels demonstrated good cytocompatibility and antioxidant performance through cell tests and 1, 1-diphenyl-2-methylbenzohydrazino (DPPH) scavenging efficiency test. The cryogels showed enhanced blood-clotting index (BCI) and better hemostatic ability in the mouse liver trauma model and the rat deep non-compressible liver defect model compared with gauze and gelatin sponge. Furthermore, compared with commercial Tegaderm TM dressing in vivo , the HA-ADH/DA cryogels could greatly promote infected skin wound healing in a full-thickness infected skin defect wound model. In summary, the macroporous HA-ADH/DA cryogels with good antioxidant, high swelling ratio, photothermal antibacterial property, and biocompatibility are a promising hemostatic material and wound healing dressing.

Molecular characterization and antioxidant activity of Volkameria inermis L.

The present investigation aimed to study the genomic characterization and free radical scavenging potential of a traditional plant Volkameria inermis. A chloroplast genome rbcL was used in molecular characterization and it revealed the phylogeny and evolutionary affinities of V. inermis with the outgroups of the family through BLAST search based on Neighbor-Joining (NJ) analysis. The free radical scavenging potential of various extracts of V. inermis was observed at different concentrations (20, 40, 60, 80 and 100 μg/mL) in DPPH and ABTS in vitro models. Ascorbic acid (DPPH) and Trolox (ABTS) were used as standard. In DPPH assay, among the different extracts (hexane, chloroform, acetone, ethanol, methanol and water) tested, methanol showed maximum scavenging activity with the IC50 value of 28.33μg/mL followed by acetone with the IC50 value of 31.937μg/mL. The other extracts, ethanol and water extracts showed moderate activity with the IC 50 value of 82.558 μg/mL and 81.758μg/mL; chloroform and hexane showed very lower antioxidant activity and the IC50 values are 518.776μg/mL, 1066.16μg/mL accordingly. In ABTS assay, methanol was observed as a highly active extracts with the IC50 value of 70.196μg/mL followed by ethanol extract (103.078μg/mL). The results showed that the methanol extract exhibits strong antioxidant activity in DPPH and ABTS assays. The scavenging efficiency showed dose dependent increase in concentration absorption compared to Ascorbic acid and Trolox. Our findings provide the molecular identification and evidence for the potential of Volkameria inermis as a source of natural antioxidants.

Chitosan films with tunable droplet size of Pickering emulsions stabilized by amphiphilic konjac glucomannan network

In this work, chitosan (CS) emulsion films were prepared with grapefruit essential oil (GEO) Pickering emulsions (OGEOs) stabilized by amphiphilic octenyl succinic anhydride (OSA) konjac glucomannan (OSA-KGM) network. The droplet size of emulsion was regulated by altering oil content in OGEOs (10 %, 20 %, 30 % and 40 %, w/w). The structural and physicochemical properties of CS films with tunable emulsion droplets (OGEOs) were investigated. The droplet size of OGEOs increased with the increasing content of GEO. FT-IR revealed that the formation of CS-OGEOs films was attributed to hydrogen bonding. CS-OGEOs films with large droplets presented smoother surface, enhanced water resistance, UV-shielding property, mechanical properties, but increased water vapor permeability (WVP) compared with CS-OGEOs films with small droplets. In addition, CS-OGEOs films with large droplets also presented compact film structure, controlled release of GEO, high efficiency of DPPH free radical scavenging and antibacterial activity. To sum up, incorporation of emulsion droplets was a good strategy for improving the structural and physicochemical properties of CS films.

Scavenging in changing environments: woody encroachment shapes rural scavenger assemblages in Europe

Rural abandonment and subsequent vegetation regeneration (‘passive rewilding') are expected to increase worldwide, producing cascades of dynamic socioeconomic, landscape and biological changes. Although landscape characteristics strongly influence the structure and functioning of scavengers, little is known about the ecological consequences of passive rewilding due to woody encroachment (i.e.‘landscape closure') on scavenging assemblages. We investigated differences in ‘scavenger assemblage composition' (species richness and abundances) and ‘scavenging efficiency' (scavenging frequency, detection and consumption times and consumption rates) in a mountain agroecosystem (Pyrenees) undergoing passive rewilding. We monitored 178 carcasses in three landscapes: ‘open', ‘shrubland' and ‘forest', and evaluated the effects of landscape type on ‘scavenger assemblage composition' and ‘scavenging efficiency' at the community and species levels, while accounting for the influences of carcass size, type and placement time. We also examined whether the locally most abundant and efficient scavenger (i.e. the griffon vultureGyps fulvus) affects scavenging patterns. We found that landscape type was the main factor governing scavenging dynamics. Overall and average scavenger richness were similar in open and shrubland landscapes, while forests contained the lowest number of scavengers, mainly comprising mammals. Unlike mammals, avian scavenging frequency decreased as vegetation cover increased, especially for obligate scavengers (i.e. vultures). Scavenger abundances were highest in open landscapes, and carcasses were detected and consumed more rapidly in these landscapes. Carcass size did not influence detection and consumption times, although it did affect average scavenger richness, abundances and consumption rates. Consumption rates were higher in open landscapes and were strongly associated with the presence of griffon vultures. Interestingly, we found that griffon vultures influenced scavenging dynamics via facilitation processes. However, woody encroachment could reduce the scavenging role of this species, while favoring mammalian facultative scavengers. Finally, our findings highlight the pivotal role of griffon vultures, mediated by landscape characteristics, in reducing carcass persistence.

Picea wilsonii Transcription Factor PwNAC38 Promotes Drought and Salt Tolerance in Transgenic Arabidopsis and Apple Calli

The mechanism of Picea wilsonii adapting to abiotic stress remains largely unknown. NAC (NAM, ATAF and CUC) transcription factors play significant roles in plant response to adverse environments. In this study, based on our previous RNA-seq, we analyzed the expression patterns of PwNAC38, and revealed its functions in the process of PwNAC38-mediated stress responses. An open-reading frame, encoding PwNAC38 protein with 330 amino acids, was isolated from the cDNA library, a process which can be induced by drought, salt and ABA treatment. Subcellular localization and yeast experiments showed that PwNAC38 was a nuclear-localized transcription factor, and could form homodimers. The full length of PwNAC38 showed transcriptional activity, while the truncated segments, C-PwNAC38 (156–330 aa) and N-PwNAC38 (1–156 aa), did not. The constitutive expression of PwNAC38 (OE lines) in Arabidopsis did not exert influence on the growth of transgenic plants under normal conditions, whereas transgenic seedlings showed higher survival rates, and the seeds had stronger vigor and a higher germination rate under drought and salt stress. The seed germination and root growth of PwNAC38 OE lines were significantly inhibited in the presence of ABA, suggesting the hypersensitivity of PwNAC38 to ABA treatment. Physiological assays showed that the activity of antioxidant enzymes, such as SOD and POD, increased, and that the accumulation of superoxide anion decreased, in OE lines under stress conditions. Moreover, overexpression of PwNAC38 significantly improved drought and salt tolerance in apple calli. A qRT-PCR assay showed that overexpression of PwNAC38 in Arabidopsis promoted the expression of drought or ABA-responsive genes ATHB-7, ANAC019, ERD1, DREB2A, RD29A, ABI5 and NCED3. Taken together, our results revealed that PwNAC38 is positively involved in plants’ response to drought and salt stress by enhancing ROS scavenging efficiency, and is partially dependent on the ABA signaling pathway.

Radiation-processed silk fibroin micro- /nano-gels as promising antioxidants: Electron beam treatment and physicochemical characterization

This study explored some aspects of the radiation-induced chemical modification of silk fibroin in pure water solution as a means to synthesize micro- /nano-gels with antioxidant properties and low cytotoxicity. The amino acid composition of the starting SF material was analyzed by NMR spectroscopy. Special attention was paid to the initial content and fate upon irradiation of the tyrosine residues. The effects of electron beam irradiation on aqueous solutions of silk fibroin was assessed by measuring structural and dimensional changes of SF particles in the solutions as a function of dose. This revealed the gradual decrease of the average hydrodynamic dimensions, initially in the 300–500 nm range for the unirradiated samples to values smaller than 100 nm for doses exceeding 20 kGy. Radical scavenging efficiency of the obtained micro- /nano-gels was assessed by DPPH-based spectrophotometric measurements which revealed the gradual enhancement of the antioxidant properties as a function of dose, yet with a correlated reduction of the scavenging kinetics. Cell viability tests have shown that introducing either the unirradiated or 10 kGy-irradiated SF micro-/nano-gels confirmed the low cytotoxicity of SF-based hydrogel materials, opening new perspectives for the radiation-mediated preparation of SF-based bioactive materials for biomedical and cosmetic applications.

Biochar Particles Obtained from Agricultural Carob Waste as a Suitable Filler for Sustainable Biocomposite Formulations.

In the context of sustainable and circular economy, the recovery of biowaste for sustainable biocomposites formulation is a challenging issue. The aim of this work is to give a new life to agricultural carob waste after glucose extraction carried out by a local factory for carob candy production. A pyrolysis process was carried out on bio-waste to produce biofuel and, later, the solid residual fraction of pyrolysis process was used as interesting filler for biocomposites production. In this work, biochar particles (BC) as a pyrolysis product, after fuels recovery of organic biowaste, specifically, pyrolyzed carobs after glucose extraction, were added on poly(butylene-adipate-co-terephthalate), (PBAT), at two different concentrations, i.e., 10 and 20 wt%. The BC have been produced using three pyrolysis processing temperatures (i.e., 280, 340 and 400 °C) to optimize the compositions of produced solid fractions and biofuels. The resulting particles from the pyrolysis process (BC280, BC340 and BC400) were considered as suitable fillers for PBAT. Firstly, the BC particles properties were characterized by elemental composition and spectroscopy analysis, particle size measurements and evaluation of radical scavenging activity and efficiency. Moreover, PBAT/BC composites were subjected to analysis of their rheological and thermal behavior, morphologies and mechanical properties. In addition, accelerated weathering, monitored by both tensile test and spectroscopic analysis, was carried out, and obtained results show that the biochar particles can exert a beneficial effect on photo-oxidation delay of PBAT matrix.