Influence of dietary phenolic acids on redox status of iron: Ferrous iron autoxidation and ferric iron reduction

We investigated the effect of dietary phenolic acids on the oxidation of Fe²⁺ caused by molecular oxygen. All phenolic acids bearing 3,4-dihydroxy (catechol) or 3,4,5-trihydroxy (galloyl) moiety formed chelates with ferric iron and significantly increased the rate of Fe²⁺ autoxidation. The carboxylate group and catechol substitution instead of galloyl moiety facilitated the ferrous ion oxidation more effectively. Caffeic acid and protocatechuic acid, the strongest accelerators of Fe²⁺ autoxidation, were able to facilitate autoxidation at concentrations lower than 1% of the initial amount of Fe²⁺. Therefore chelates of these catecholic acids with iron displayed ferroxidase-like activity. Conversely, when we started from ferric ions, catechols partially formed ferrous ions in the presence of ferrozine. Thus, catecholic acids formed stable chelates with iron, in which ferric ion is the dominant species, but the redox cycling of iron between Fe²⁺ and Fe³⁺ in chelates probably plays a crucial role in the catalysis of ferrous iron autoxidation. Interestingly, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid and vanillic (4-hydroxy-3-methoxybenzoic) acid protected ferrous ions from autoxidation as effectively as ascorbic acid and cysteine. These monophenolic acids, differently from ascorbic acid and cysteine, were not able to reduce ferric ions. Syringic (3,5-dimethoxy-4-hydroxybenzoic) acid did not alter the redox state of iron, only in a large excess over metal, syringic acid slightly inhibited ferrous ions autoxidation and partially reduced ferric ions. Therefore, the effects of syringic acid at high concentration were similar but much lower to those of ascorbic acid and cysteine. The biological importance of ferroxidase-like activity of polyphenols, especially the influence on iron absorption, is also discussed.     

The effect of composition of a polymeric coating on the biofilm formation of bacteria and filamentous fungi

Functionality of polymeric coating, especially in terms of anti-corrosive properties and stability, can be negatively influenced by formation of either bacterial or fungal biofilm on its surface. Herein, the epoxy-ester resin based polymeric coating was filled with pigments (natural silicon dioxide diatomite, natural wollastonite, tungstate and molybdate). Pigments was modified by conducting polymers (polyaniline phosphate, polypyrrole phosphate, poly(p-phenylenediamine) phosphate and ZnFe₂O₄). Impact of modified pigments on the surface energy and formation of biofilm were tested. The use of various biofilm forming species of both the bacteria and fungi filled a knowledge gap about their behavior on polymeric coatings.     

A gel probe equilibrium sampler for measuring arsenic porewater profiles and sorption gradients in sediments: II. Field application to Haiwee Reservoir sediment

Arsenic (As) geochemistry and sorption behavior were measured in As- and iron (Fe)-rich sediments of Haiwee Reservoir by deploying undoped (clear) polyacrylamide gels and hydrous ferric oxide (HFO)-doped gels in a gel probe equilibrium sampler, which is a novel technique for directly measuring the effects of porewater composition on As adsorption to Fe oxides phases in situ. Arsenic is deposited atthe sedimentsurface as As(V) and is reduced to As(III) in the upper layers of the sediment (0-8 cm), but the reduction of As(V) does not cause mobilization into the porewater. Dissolved As and Fe concentrations increased at depth in the sediment column driven by the reductive dissolution of amorphous Fe(III) oxyhydroxides and conversion to a mixed Fe(II, III) green rust-type phase. Adsorption of As and phosphorous (P) onto HFO-doped gels was inhibited at intermediate depths (10-20 cm), possibly due to dissolved organic or inorganic carbon, indicating that dissolved As concentrations were at least partially controlled by porewater composition rather than surface site availability. In sediments that had been recently exposed to air, the region of sorption inhibition was not observed, suggesting that prior exposure to air affected the extent of reductive dissolution, porewater chemistry, and As adsorption behavior. Arsenic adsorption onto the HFO-doped gels increased at depths >20 cm, and the extent of adsorption was most likely controlled by the competitive effects of dissolved phosphate. Sediment As adsorption capacity appeared to be controlled by changes in porewater composition and competitive effects at shallower depths, and by reductive dissolution and availability of sorption sites at greater burial depths.     

Decellularised Human Umbilical Artery as a Vascular Graft Elicits Minimal Pro-Inflammatory Host Response Ex Vivo and In Vivo

Small diameter (<6 mm) vessel grafts still pose a challenge for scientists worldwide. Decellularised umbilical artery (dUA) remains promising as small diameter tissue engineered vascular graft (TEVG), yet their immunogenicity remains unknown. Herein, we evaluated the host immune responses, with a focus on the innate part, towards human dUA implantation in mice, and confirmed our findings in an ex vivo allogeneic human setup. Overall, we did not observe any differences in the number of circulating white blood cells nor the number of monocytes among three groups of mice (1) dUA patch; (2) Sham; and (3) Mock throughout the study (day −7 to 28). Likewise, we found no difference in systemic inflammatory and anti-inflammatory cytokine levels between groups. However, a massive local remodelling response with M2 macrophages were observed in the dUA at day 28, whereas M1 macrophages were less frequent. Moreover, human monocytes from allogeneic individuals were differentiated into macrophages and exposed to lyophilised dUA to maximize an eventual M1 response. Yet, dUA did not elicit any immediate M1 response as determined by the absence of CCR7 and CXCL10. Together this suggests that human dUA elicits a minimal pro-inflammatory response further supporting its use as a TEVG in an allogeneic setup.     

Sesquiterpenes in grapes and wines: Occurrence,biosynthesis, functionality,and influence of winemaking processes

Grapes are an important global horticultural product, and are mainly used for winemaking. Typically, grapes and wines are rich in various phytochemicals, including phenolics, terpenes, pyrazines, and benzenoids, with different compounds responsible for different nutritional and sensory properties. Among these compounds, sesquiterpenes, a subcategory of the terpenes, are attracting increasing interest as they affect aroma and have potential health benefits. The characteristics of sesquiterpenes in grapes and wines in terms of classification, biosynthesis pathway, and active functions have not been extensively reviewed. This paper summarizes 97 different sesquiterpenes reported in grapes and wines and reviews their biosynthesis pathways and relevant bio‐regulation mechanisms. This review further discusses the functionalities of these sesquiterpenes including their aroma contribution to grapes and wines and potential health benefits, as well as how winemaking processes affect sesquiterpene concentrations.     

Instance space analysis for a personnel scheduling problem

Annals of Mathematics and Artificial Intelligence - This paper considers the Rotating Workforce Scheduling Problem, and shows how the strengths and weaknesses of various solution methods can be...     

Exploration of Electrochemical Reactions at Organic–Inorganic Halide Perovskite Interfaces via Machine Learning in In Situ Time‐of‐Flight Secondary Ion Mass Spectrometry

The instability of hybrid organic–inorganic perovskite (HOIP) devices is one of the significant challenges preventing commercialization. Exploring these phenomena is severely limited by the complexity of the intrinsic electrochemistry of HOIPs, the presence of multiple volatile and mobile ionic species, and the possible role of environmentally induced reactions at surfaces and triple‐phase junctions. Here, in situ studies of the electrochemistry of methylammonium lead bromide perovskite with the Au electrode interface are reported via light‐ and voltage‐dependent time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) imaging of lateral perovskite heterostructures. While ToF‐SIMS allows for the visualization of the chemical composition along the surface and its evolution with light and electrical bias, the interpretation of the multidimensional data obtained is often limited due to strong correlations between chemical signatures and the need to track multiple peaks at once. Here, a machine learning workflow combining the Hough transform and non‐negative matrix factorization and non‐negative tensor decomposition is developed to avoid this limitation and extract salient features of associated chemical changes and to separate the light‐ and voltage‐dependent dynamics. Combining these in situ characterizations and the machine learning workflow provides comprehensive information on the chemical nature of moving species, ion accumulation, and interfacial electrochemical reactions in HOIP devices.     

A 3D Magnetic Hyaluronic Acid Hydrogel for Magnetomechanical Neuromodulation of Primary Dorsal Root Ganglion Neurons

Neuromodulation tools are useful to decipher and modulate neural circuitries implicated in functions and diseases. Existing electrical and chemical tools cannot offer specific neural modulation while optogenetics has limitations for deep tissue interfaces, which might be overcome by miniaturized optoelectronic devices in the future. Here, a 3D magnetic hyaluronic hydrogel is described that offers noninvasive neuromodulation via magnetomechanical stimulation of primary dorsal root ganglion (DRG) neurons. The hydrogel shares similar biochemical and biophysical properties as the extracellular matrix of spinal cord, facilitating healthy growth of functional neurites and expression of excitatory and inhibitory ion channels. By testing with different neurotoxins, and micropillar substrate deflections with electrophysical recordings, it is found that acute magnetomechanical stimulation induces calcium influx in DRG neurons primarily via endogenous, mechanosensitive TRPV4 and PIEZO2 channels. Next, capitalizing on the receptor adaptation characteristic of DRG neurons, chronic magnetomechanical stimulation is performed and found that it reduces the expression of PIEZO2 channels, which can be useful for modulating pain where mechanosensitive channels are typically overexpressed. A general strategy is thus offered for neuroscientists and material scientists to fabricate 3D magnetic biomaterials tailored to different types of excitable cells for remote magnetomechanical modulation.     

A cross-entropy method for optimising robotic automated storage and retrieval systems

In this paper, we consider a robotic automated storage and retrieval system (AS/RS) where a Cartesian robot picks and palletises items onto a mixed pallet for any order. This robotic AS/RS not only retrieves orders in an optimal sequence, but also creates an optimal store ready pallet of any order. Adapting the Travelling Salesman Problem to warehousing, the decision to be made includes finding the optimal sequence of orders, and optimal sequence of items inside each order, that jointly minimise total travel times. In the first phase, as a control problem, we develop an avoidance strategy for the robot (or automatic stacker crane) movement sequence. This approach detects the collision occurrence causing unsafe handling of hazardous items and prevents the occurrence of it by a collision-free robot movement sequence. Due to the complexity of the problem, the second phase is attacked by a Cross-Entropy (CE) method. To evaluate the performance of the CE method, a computational analysis is performed over various test problems. The results obtained from the CE method are compared to those of the optimal solutions obtained using CPLEX. The results indicate high performance of the solution procedure to solve the sequencing problem of robotic AS/RSs.