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Open AccessArticle
Interactions of Small-Molecule Guests with Interior and Exterior Surfaces of a Coordination Cage Host
Chemistry 2020, 2(2), 510-524; https://doi.org/10.3390/chemistry2020031 (registering DOI) - 02 Jun 2020
Abstract
Coordination cages are well-known to act as molecular containers that can bind small-molecule guests in their cavity. Such cavity binding is associated with interactions of the guests with the surrounding set of surfaces that define the cavity; a guest that is a good [...] Read more.
Coordination cages are well-known to act as molecular containers that can bind small-molecule guests in their cavity. Such cavity binding is associated with interactions of the guests with the surrounding set of surfaces that define the cavity; a guest that is a good fit for the cavity will have many favourable interactions with the interior surfaces of the host. As cages have exterior as well as interior surfaces, possibilities also exist for ‘guests’ that are not well-bound in the cavity to interact with the exterior surface of the cage where spatial constraints are fewer. In this paper, we report a combined solid-state and solution study using an octanuclear cubic M8L12 coordination cage which illustrates the occurrence of both types of interaction. Firstly, crystallographic studies show that a range of guests bind inside the cavity (either singly or in stacked pairs) and/or interact with the cage exterior surface, depending on their size. Secondly, fluorescence titrations in aqueous solution show how some flexible aromatic disulfides show two separate types of interaction with the cage, having different spectroscopic consequences; we ascribe this to separate interactions with the exterior surface and the interior surface of the host cage with the former having a higher binding constant. Overall, it is clear that the idea of host/guest interactions in molecular containers needs to take more account of external surface interactions as well as the obvious cavity-based binding. Full article
(This article belongs to the Section Supramolecular Chemistry)
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Open AccessArticle
Modeling Volatility Characteristics of Epileptic EEGs using GARCH Models
Signals 2020, 1(1), 26-46; https://doi.org/10.3390/signals1010003 (registering DOI) - 02 Jun 2020
Abstract
Objective: To determine if there was a difference in the volatility characteristics of seizure and non-seizure onset channels in the intracranial electroencephalogram (EEG) in a patient with temporal lobe epilepsy. Methods: The half-life of volatility for the different EEG channels was determined using [...] Read more.
Objective: To determine if there was a difference in the volatility characteristics of seizure and non-seizure onset channels in the intracranial electroencephalogram (EEG) in a patient with temporal lobe epilepsy. Methods: The half-life of volatility for the different EEG channels was determined using Autoregressive Moving Average–Generalized Autoregressive Conditional Heteroscedasticity (ARMA–GARCH) models; confidence intervals were constructed using the delta method and an asymptotic method for comparing the half-lives. Results: Clinically determined seizure onsets occurred over strip electrodes named RAST (Right Anterior Subtemporal) and RMST (Right Mid Subtemporal), at locations 2, 3 and 4, on the strip electrodes. The half-lives of volatility for two of the three seizure channels, RAST3 and RAST4, were found to be significantly lower the rest of the channels for six one-minute EEG segments prior to seizure onset and nine one-minute EEG segments of an awake state. The half-lives of volatility for RAST3 and RAST4 were not significantly different to the non-seizure channels for ten one-minute segments of sleep and ten one-minute segments of sleep-to-awake states. The estimates for the half-lives were consistent for randomly selected one-minute EEG segments. Conclusions: The use of GARCH models may be a useful tool in determining hidden properties in epileptiform EEGs that may lead to better understanding of the seizure generating process. Full article
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Open AccessFeature PaperBrief Report
Human Brain Shows Recurrent Non-Canonical MicroRNA Editing Events Enriched for Seed Sequence with Possible Functional Consequence
Non-Coding RNA 2020, 6(2), 21; https://doi.org/10.3390/ncrna6020021 (registering DOI) - 02 Jun 2020
Abstract
RNA editing is a post-transcriptional modification, which can provide tissue-specific functions not encoded in DNA. Adenosine-to-inosine is the predominant editing event and, along with cytosine-to-uracil changes, constitutes canonical editing. The rest is non-canonical editing. In this study, we have analysed non-canonical editing of [...] Read more.
RNA editing is a post-transcriptional modification, which can provide tissue-specific functions not encoded in DNA. Adenosine-to-inosine is the predominant editing event and, along with cytosine-to-uracil changes, constitutes canonical editing. The rest is non-canonical editing. In this study, we have analysed non-canonical editing of microRNAs in the human brain. We have performed massively parallel small RNA sequencing of frontal cortex (FC) and corpus callosum (CC) pairs from nine normal individuals (post-mortem). We found 113 and 90 unique non-canonical editing events in FC and CC samples, respectively. More than 70% of events were in the miRNA seed sequence—implicating an altered set of target mRNAs and possibly resulting in a functional consequence. Up to 15% of these events were recurring and found in at least three samples, also supporting the biological relevance of such variations. Two specific sequence variations, C-to-A and G-to-U, accounted for over 80% of non-canonical miRNA editing events—and revealed preferred sequence motifs. Our study is one of the first reporting non-canonical editing in miRNAs in the human brain. Our results implicate miRNA non-canonical editing as one of the contributing factors towards transcriptomic diversity in the human brain. Full article
(This article belongs to the Special Issue Non-Coding RNAs: Variations and Disease)
Open AccessFeature PaperArticle
Overexpression of Kif1A in the Developing Drosophila Heart Causes Valvar and Contractility Defects: Implications for Human Congenital Heart Disease
J. Cardiovasc. Dev. Dis. 2020, 7(2), 22; https://doi.org/10.3390/jcdd7020022 (registering DOI) - 02 Jun 2020
Abstract
Left-sided congenital heart defects (CHDs) are among the most common forms of congenital heart disease, but a disease-causing gene has only been identified in a minority of cases. Here, we identified a candidate gene for CHDs, KIF1A, that was associated with a [...] Read more.
Left-sided congenital heart defects (CHDs) are among the most common forms of congenital heart disease, but a disease-causing gene has only been identified in a minority of cases. Here, we identified a candidate gene for CHDs, KIF1A, that was associated with a chromosomal balanced translocation t(2;8)(q37;p11) in a patient with left-sided heart and aortic valve defects. The breakpoint was in the 5′ untranslated region of the KIF1A gene at 2q37, which suggested that the break affected the levels of Kif1A gene expression. Transgenic fly lines overexpressing Kif1A specifically in the heart muscle (or all muscles) caused diminished cardiac contractility, myofibrillar disorganization, and heart valve defects, whereas cardiac knockdown had no effect on heart structure or function. Overexpression of Kif1A also caused increased collagen IV deposition in the fibrous network that normally surrounds the fly heart. Kif1A overexpression in C2C12 myoblasts resulted in specific displacement of the F-actin fibers, probably through a direct interaction with G-actin. These results point to a Kif1A-mediated disruption of F-actin organization as a potential mechanism for the pathogenesis in at least some human CHDs. Full article
Open AccessArticle
Microencapsulation of Pineapple Peel Extract by Spray Drying Using Maltodextrin, Inulin, and Arabic Gum as Wall Matrices
Foods 2020, 9(6), 718; https://doi.org/10.3390/foods9060718 - 02 Jun 2020
Abstract
A pineapple peel hydroalcoholic extract rich in phenolic compounds, was stabilized by microencapsulation using spray drying technology, with maltodextrin, inulin, and arabic gum as wall materials. The influence of the type of wall material and drying temperature (150 and 190 °C) on the [...] Read more.
A pineapple peel hydroalcoholic extract rich in phenolic compounds, was stabilized by microencapsulation using spray drying technology, with maltodextrin, inulin, and arabic gum as wall materials. The influence of the type of wall material and drying temperature (150 and 190 °C) on the particles properties was studied. The particles presented a spherical shape with a diameter ranging from approximately 1.3 to 18.2 µm, the exception being the ones with inulin that showed a large degree of agglomeration. All powders produced presented an intermediate cohesiveness and a fair to good flowability according to Carr index and Hausner ratio, which envisages suitable handling properties at an industrial scale. The microencapsulation processes using maltodextrin and arabic gum at 150 °C were the ones that showed higher maintenance of the antioxidant activity of compounds present in the extract before encapsulation during spray drying. In addition, the microparticles obtained were quite efficient in stabilizing the encapsulated phenolic compounds, as their antioxidant activity did not change significantly during six months of storage at 5 °C. Full article
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Open AccessFeature PaperArticle
Metric f-Contact Manifolds Satisfying the (κ, μ)-Nullity Condition
Mathematics 2020, 8(6), 891; https://doi.org/10.3390/math8060891 - 02 Jun 2020
Abstract
We prove that if the f-sectional curvature at any point of a (2n+s)-dimensional metric f-contact manifold satisfying the (κ,μ) nullity condition with n>1 is independent of the f-section [...] Read more.
We prove that if the f-sectional curvature at any point of a ( 2 n + s ) -dimensional metric f-contact manifold satisfying the ( κ , μ ) nullity condition with n > 1 is independent of the f-section at the point, then it is constant on the manifold. Moreover, we also prove that a non-normal metric f-contact manifold satisfying the ( κ , μ ) nullity condition is of constant f-sectional curvature if and only if μ = κ + 1 and we give an explicit expression for the curvature tensor field in such a case. Finally, we present some examples. Full article
(This article belongs to the Special Issue Sasakian Space)
Open AccessArticle
Characterization of Single Event Cell Upsets in a Radiation Hardened SRAM in a 40 nm Bulk CMOS Technology
Electronics 2020, 9(6), 927; https://doi.org/10.3390/electronics9060927 (registering DOI) - 02 Jun 2020
Abstract
A large amount of data needs to be stored in integrated circuits when data are being processed. The integrated circuits contain a large amount of static random access memory (SRAM) due to its high level of integration and speed. SRAM units should be [...] Read more.
A large amount of data needs to be stored in integrated circuits when data are being processed. The integrated circuits contain a large amount of static random access memory (SRAM) due to its high level of integration and speed. SRAM units should be as small as possible to achieve higher storage density. In this work, the features of single cell upsets (SCUs) and multiple cell upsets (MCUs) in a full custom SRAM are tested for a 40 nm bulk CMOS technology node, and Ge (linear energy transfer (LET) = 37.3 MeV cm2/mg), Cl (LET = 13.1 MeV cm2/mg), Al (LET = 8.6 MeV cm2/mg), O (LET = 3.1 MeV cm2/mg), and Li (LET = 0.5 MeV cm2/mg) particles are used. The test results show that the total single cell upset events are 2,000,147, 1,124,269, 413,100, 311,311, and 47,815 under the irradiation of Ge, Cl, Al, O, and Li, respectively. Moreover, due to single event upset reversal mechanism, multiple cell upsets significantly decrease. The total multiple cell upset events are 10, 4, 0, 0, and 0 under the irradiation of Ge, Cl, Al, O, and Li, respectively. There are a lot of single cell upsets appearing under Ge, Cl, Al, O, and Li exposure. The number is increasing with increasing LET, which means that well contacts still need optimization in the full custom SRAM. Close spacing of well contacts or increasing contacts are the approaches used to drain the excess carriers quickly, and error detection and correction (EDAC) is used for SRAM technology. The features show that SCUs have become a major source of soft errors for the full custom SRAM. Combining close spacing of well contacts with error detection and correction (EDAC) and a well engineering scheme are used to reduce single cell upsets, although there are a few MCUs which are inevitable. Radiation hardened by design schemes needs to be further improved. Full article
Open AccessReview
Cannabinoids‐Promising Antimicrobial Drugs or Intoxicants with Benefits?
Antibiotics 2020, 9(6), 297; https://doi.org/10.3390/antibiotics9060297 (registering DOI) - 02 Jun 2020
Abstract
Novel antimicrobial drugs are urgently needed to counteract the increasing occurrence of
bacterial resistance. Extracts of Cannabis sativa have been used for the treatment of several diseases
since ancient times. However, its phytocannabinoid constituents are predominantly associated with
psychotropic effects and medical applications [...] Read more.
Novel antimicrobial drugs are urgently needed to counteract the increasing occurrence of
bacterial resistance. Extracts of Cannabis sativa have been used for the treatment of several diseases
since ancient times. However, its phytocannabinoid constituents are predominantly associated with
psychotropic effects and medical applications far beyond the treatment of infections. It has been
demonstrated that several cannabinoids show potent antimicrobial activity against primarily Grampositive
bacteria including methicillin‐resistant Staphylococcus aureus (MRSA). As first in vivo
efficacy has been demonstrated recently, it is time to discuss whether cannabinoids are promising
antimicrobial drug candidates or overhyped intoxicants with benefits. Full article
(This article belongs to the Special Issue Antimicrobial Activity of Higher Plants)
Open AccessFeature PaperArticle
Tracking Control for an Electro-Hydraulic Rotary Actuator Using Fractional Order Fuzzy PID Controller
Electronics 2020, 9(6), 926; https://doi.org/10.3390/electronics9060926 (registering DOI) - 02 Jun 2020
Abstract
This paper presents a strategy for a fractional order fuzzy proportional integral derivative controller (FOFPID) controller for trajectory-tracking control of an electro-hydraulic rotary actuator (EHRA) under variant working requirements. The proposed controller is based on a combination of a fractional order PID (FOPID) [...] Read more.
This paper presents a strategy for a fractional order fuzzy proportional integral derivative controller (FOFPID) controller for trajectory-tracking control of an electro-hydraulic rotary actuator (EHRA) under variant working requirements. The proposed controller is based on a combination of a fractional order PID (FOPID) controller and a fuzzy logic system. In detail, the FOPID with extension from the integer order to non-integer order of integral and derivative functions helps to improve tracking, robustness and stability of the control system. A fuzzy logic control system is designed to adjust the FOPID parameters according to time-variant working conditions. To evaluate the proposed controller, co-simulations (using AMESim and MATLAB) and real-time experiments have been conducted. The results show the effectiveness of the proposed approach compared to other typical controllers. Full article
Open AccessArticle
Effect of SiC/Fly Ash Reinforcement on Surface Properties of Aluminum 7075 Hybrid Composites
Coatings 2020, 10(6), 541; https://doi.org/10.3390/coatings10060541 - 02 Jun 2020
Abstract
Friction stir processing (FSP) has emerged as a valuable technique in the surface metal matrix composite fabrication field. In this process, solid-state processing mostly avoids the formation of detrimental phases inside composites. Despite having a high specific strength, further extensive Al alloy applications [...] Read more.
Friction stir processing (FSP) has emerged as a valuable technique in the surface metal matrix composite fabrication field. In this process, solid-state processing mostly avoids the formation of detrimental phases inside composites. Despite having a high specific strength, further extensive Al alloy applications are limited due to their poor surface properties. A hybrid reinforcement approach can be used to improve surface properties. In this study, industrial waste fly ash material is mixed with hard SiC ceramic particles. The main focus of this research is to improve wear resistance under dry sliding conditions and microhardness of aluminum 7075-T651 by dispersion of silicon carbide-fly ash (SiC/fly ash) powder in a base alloy by FSP. The parameters used for this investigation are: tool rotation rpm (500, 1000 and 1500), the tool traverse mm/min (20, 30 and 40), the reinforcement’s hybrid ratio HR (60:40, 75:25 and 90:10) and the volume percentage vol.% (4%, 8% and 12%). The influence of these parameters on the resultant composite’s microstructure, dry sliding wear rate and micro-hardness was studied. By using response surface methodology (RSM), desirable ranges of process parameters for lower wear rate and higher microhardness were obtained. The interaction effect of SiC/fly ash volume percentage and hybrid ratio had the most influential effect on the wear rates, as well as microhardness of composites. Moreover, microhardness increased with an increase in the volume percentage of SiC/fly ash powders towards high SiC content in hybrid ratio. Interestingly, among stirring parameters, tool traverse speed was found to be more influential than tool rotational speed. The minimum wear rate was observed for the Run 20 sample (w: 1000 rpm, v: 40 mm/min, HR: 75:25, vol.%: 8). A maximum microhardness of 241.20 HV was achieved for Run 15 (w: 500 rpm, v: 40 mm/min, HR: 90:10, vol.%: 12) sample. Mainly, reinforcement distribution—in accordance with the stirring action generated by the tool—had a major role in controlling the surface properties of the resultant composites. Full article
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Open AccessArticle
Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China
J. Mar. Sci. Eng. 2020, 8(6), 403; https://doi.org/10.3390/jmse8060403 (registering DOI) - 02 Jun 2020
Abstract
Dissolved oxygen (DO) is one of the most important factors for maintaining a healthy marine ecosystem. The information of DO in large estuaries or bays with large entrances has been widely studied, while it is relatively limited for a bay with a narrow [...] Read more.
Dissolved oxygen (DO) is one of the most important factors for maintaining a healthy marine ecosystem. The information of DO in large estuaries or bays with large entrances has been widely studied, while it is relatively limited for a bay with a narrow entrance which is vulnerable to human activities. The Zhanjiang Bay, located in the northwestern South China Sea, has a very narrow entrance and suffers from strong anthropogenic activities and obvious seasonal variations in environmental parameters. In this study, we analyzed the spatial and monthly variations of DO, apparent oxygen utilization (AOU), percent oxygen saturation (DO-saturation), and related environmental parameters in the surface water of Zhanjiang Bay to find out the factors controlling the dynamics of DO. Different from many other coastal ecosystems, DO concentrations in the Zhanjiang Bay reached minimum values in late spring and early autumn. The phytoplankton bloom in summer months, which was related to the high concentrations of nutrients brought by rainfall-induced terrestrial inputs, contributed to that phenomenon. Though high chlorophyll a (Chl a) concentrations were observed in both the summer months and December, the DO-saturation values were relatively low and AOU values were relatively high in summer months. Rainfall-induced terrestrial discharge in summer months, which had high concentrations of chemical oxygen demand, contributed much to that phenomenon. The average DO concentrations and DO-saturation values in a hydrological year decreased seaward, and AOU values increased seaward, indicating the anthropogenic influence from terrestrial input. The highest annual average Chl a concentration, relatively high annual average DO-saturation value and relatively low annual AOU value were observed near the Donghai Dam. This indicated that the construction of Donghai Dam has significant influences on the environment of Zhanjiang Bay. Full article
(This article belongs to the Special Issue Marine Observation and Monitoring towards an Ecosystem Approach)
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Open AccessFeature PaperArticle
Trajectories of Changes in Phytoplankton Biomass, Phaeocystis globosa and Diatom (incl. Pseudo-nitzschia sp.) Abundances Related to Nutrient Pressures in the Eastern English Channel, Southern North Sea
J. Mar. Sci. Eng. 2020, 8(6), 401; https://doi.org/10.3390/jmse8060401 - 02 Jun 2020
Abstract
The phytoplankton compartment is particularly reactive to changes in nutrient concentration and is used as a quality indicator. Using a simple numerical approach, the response of emblematic harmful taxa from the eastern English Channel and southern North Sea to changes in nutrient inputs [...] Read more.
The phytoplankton compartment is particularly reactive to changes in nutrient concentration and is used as a quality indicator. Using a simple numerical approach, the response of emblematic harmful taxa from the eastern English Channel and southern North Sea to changes in nutrient inputs was studied. The method is based on a diachronic approach using averaged maxima over sliding periods of six years (1994–2018). This gave a final dataset containing pairs of points (number of years) for explained and explanatory variables. The temporal trajectory of the relationship between each pair of variables was then highlighted. Changes were represented as long-term trajectories that allowed a comparison to a reference/average situation. In addition, the relevance of the use of Phaeocystis globosa and the Pseudo-nitzchia complex as eutrophication species indicators was tested. Results showed a significant shift in the 2000s and different trajectories between diatoms and P. globosa abundances in response to changes in Dissolved Inorganic Nitrogen (DIN). The contrasting ecosystems under study reacted differently depending on the initial pressure. While a return to good ecological status does not seem feasible in the short term, it seems that these ecosystems were in an unstable intermediate state requiring continued efforts to reduce nutrient inputs. Full article
(This article belongs to the Special Issue Marine Observation and Monitoring towards an Ecosystem Approach)
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Open AccessArticle
The Impact of Intellectual Capital Efficiency on Corporate Sustainable Growth-Evidence from Smart Agriculture in China
Agriculture 2020, 10(6), 199; https://doi.org/10.3390/agriculture10060199 (registering DOI) - 02 Jun 2020
Abstract
In this paper, we expand the value-added intellectual coefficient (VAIC) model by constructing a comprehensive financial capital (FC) component. Human capital efficiency is subdivided into executive (EHCE) and nonexecutive human capital efficiency (NHCE). We have sampled listed agriculture companies (LAC) in China’s Shanghai [...] Read more.
In this paper, we expand the value-added intellectual coefficient (VAIC) model by constructing a comprehensive financial capital (FC) component. Human capital efficiency is subdivided into executive (EHCE) and nonexecutive human capital efficiency (NHCE). We have sampled listed agriculture companies (LAC) in China’s Shanghai and Shenzhen A-share markets from 2009 to 2018 and categorized them as high-tech (HTAC) and non-high-tech agriculture companies (NHTAC). We find that capital employed efficiency (CEE) and EHCE have a significant positive effect on corporate sustainable growth (CSG) of HTAC but no significant effect on CSG of NHTAC, while FC has a significant positive effect on both. These results suggest that companies, especially HTAC, should invest in human capital, and their executives and policymakers should develop effective knowledge management tools and begin accumulating the necessary intellectual capital to allow adaptation to their changing environment. In the spirit of the intellectual agriculture concept, we present some new ways to study the performance of agricultural companies using intellectual capital and offer suggestions that can help to modernize the industry. Full article
(This article belongs to the Special Issue Productivity, Efficiency, and Sustainability in Agriculture)
Open AccessArticle
A Compact High-Efficient Equivalent Circuit Model of Multi-Quantum-Well Vertical-Cavity Surface-Emitting Lasers for High-Speed Interconnects
Appl. Sci. 2020, 10(11), 3865; https://doi.org/10.3390/app10113865 - 02 Jun 2020
Abstract
Due to their low power consumption, high modulation speed, and low cost, vertical-cavity surface-emitting lasers (VCSEL) dominate short-reach data communications as the light source. In this paper, we propose a compact equivalent circuit model with noise effects for high-speed multi-quantum-well (MQW) VCSELs. The [...] Read more.
Due to their low power consumption, high modulation speed, and low cost, vertical-cavity surface-emitting lasers (VCSEL) dominate short-reach data communications as the light source. In this paper, we propose a compact equivalent circuit model with noise effects for high-speed multi-quantum-well (MQW) VCSELs. The model comprehensively accounts for the carrier and photons dynamisms of a MQW structure, which includes separate confinement heterostructure (SCH) layers, barrier (B) layers, and quantum well (QW) layers. The proposed model is generalized to various VCSEL designs and accommodates a flexible number of quantum wells. Experimental validation of the model is performed at 25 Gb/s with a self-wire-bonded 850 nm VCSEL. Full article
Open AccessReview
An Update on Mitochondrial Reactive Oxygen Species Production
Antioxidants 2020, 9(6), 472; https://doi.org/10.3390/antiox9060472 - 02 Jun 2020
Abstract
Mitochondria are quantifiably the most important sources of superoxide (O2) and hydrogen peroxide (H2O2) in mammalian cells. The overproduction of these molecules has been studied mostly in the contexts of the pathogenesis of human diseases [...] Read more.
Mitochondria are quantifiably the most important sources of superoxide (O2) and hydrogen peroxide (H2O2) in mammalian cells. The overproduction of these molecules has been studied mostly in the contexts of the pathogenesis of human diseases and aging. However, controlled bursts in mitochondrial ROS production, most notably H2O2, also plays a vital role in the transmission of cellular information. Striking a balance between utilizing H2O2 in second messaging whilst avoiding its deleterious effects requires the use of sophisticated feedback control and H2O2 degrading mechanisms. Mitochondria are enriched with H2O2 degrading enzymes to desensitize redox signals. These organelles also use a series of negative feedback loops, such as proton leaks or protein S-glutathionylation, to inhibit H2O2 production. Understanding how mitochondria produce ROS is also important for comprehending how these organelles use H2O2 in eustress signaling. Indeed, twelve different enzymes associated with nutrient metabolism and oxidative phosphorylation (OXPHOS) can serve as important ROS sources. This includes several flavoproteins and respiratory complexes I-III. Progress in understanding how mitochondria generate H2O2 for signaling must also account for critical physiological factors that strongly influence ROS production, such as sex differences and genetic variances in genes encoding antioxidants and proteins involved in mitochondrial bioenergetics. In the present review, I provide an updated view on how mitochondria budget cellular H2O2 production. These discussions will focus on the potential addition of two acyl-CoA dehydrogenases to the list of ROS generators and the impact of important phenotypic and physiological factors such as tissue type, mouse strain, and sex on production by these individual sites. Full article
(This article belongs to the Special Issue Redox and Nitrosative Signaling and Stress)
Open AccessArticle
Anthocyanins in Blueberries Grown in Hot Climate Exert Strong Antioxidant Activity and May Be Effective against Urinary Tract Bacteria
Antioxidants 2020, 9(6), 478; https://doi.org/10.3390/antiox9060478 (registering DOI) - 02 Jun 2020
Abstract
Anthocyanins are extensively studied for their health-related properties, including antibacterial activity against urinary tract infections (UTI). Among common fruits, blueberries, with their remarkable antioxidant capacity, are one of the richest sources. Anthocyanin-rich extracts were obtained from four varieties: Snowchaser, Star, Stella Blue and [...] Read more.
Anthocyanins are extensively studied for their health-related properties, including antibacterial activity against urinary tract infections (UTI). Among common fruits, blueberries, with their remarkable antioxidant capacity, are one of the richest sources. Anthocyanin-rich extracts were obtained from four varieties: Snowchaser, Star, Stella Blue and Cristina Blue, grown in the hot climate of Southern Spain. Their total anthocyanins contents (TAC) were determined spectrophotometrically, and the anthocyanin profile by ultra high performance liquid chromatography - tandem mass spectrometer (UHPLC-MS/MS). Their antioxidant activity was assessed by oxygen radical absorbance capacity (ORAC) assay, while antibacterial activity against strains isolated from UTI patients was assessed in vitro, helping to select the varieties with the highest bioactive potential. Star showed the highest TAC and antioxidant activity (1663 ± 159 mg of cyanidin-3-O-glucoside (cy-3-O-glu) equivalents/100 g fresh weight (FW), 6345 ± 601 μmol Trolox equivalents (TE)/100 g FW, respectively), followed by Cristina Blue, Stella Blue and Snowchaser. As far as we know, this is the first time that cyanidin-3-rutinoside has been identified in blueberries. The extracts inhibited all the tested strains, MICs ranging from 0.4 mg/mL (for Stella Blue extract against UTI P. aeruginosa) to 9.5 mg/mL (for all extracts against UTI K. pneumoniae ssp. pneumoniae). This is the first study that assessed in vitro the antibacterial activity of blueberries against Klebsiella pneumoniae, Providencia stuartii and Micrococcus spp. strains isolated from UTI. Full article
(This article belongs to the Special Issue Antioxidant capacity of Anthocyanins and Other Vegetal Pigments)
Open AccessArticle
(−)-Loliolide Isolated from Sargassum horneri Protects against Fine Dust-Induced Oxidative Stress in Human Keratinocytes
Antioxidants 2020, 9(6), 474; https://doi.org/10.3390/antiox9060474 - 02 Jun 2020
Abstract
The emergence of fine dust (FD) among air pollutants has taken a toll during the past few decades, and it has provided both controversy and a platform for open conversation amongst world powers for finding sustainable solutions and effective treatments for health issues. [...] Read more.
The emergence of fine dust (FD) among air pollutants has taken a toll during the past few decades, and it has provided both controversy and a platform for open conversation amongst world powers for finding sustainable solutions and effective treatments for health issues. The present study emphasizes the protective effects of (–)-loliolide (HTT) isolated from Sargassum horneri against FD-induced oxidative stress in human HaCaT keratinocytes. The purification of (–)-loliolide was carried out by centrifugal partition chromatography. HTT did not show any cytotoxicity, and it further illustrated the potential to increase cell viability by reducing the reactive oxygen species (ROS) production in FD-stimulated keratinocytes. Furthermore, HTT suppressed FD-stimulated DNA damage and the formation of apoptotic bodies, and it reduced the population of cells in the sub-G1 apoptosis phase. FD-induced apoptosis was advancing through the mitochondria-mediated apoptosis pathway. The cytoprotective effects of the HTT against FD-stimulated oxidative damage is mediated through squaring the nuclear factor E2-related factor 2 (Nrf2)-mediated heme oxygenase-1 (HO-1) pathway, dose-dependently increasing HO-1 and NAD(P)H dehydrogenase (quinone) 1 (NQO1) levels in the cytosol while concomitantly improving the nuclear translocation of Nrf2. Future studies could implement the protective functionality of HTT in producing pharmaceuticals that utilize natural products and benefit the diseased. Full article
(This article belongs to the Special Issue Oxidative Stress Modulators and Functional Foods)
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