Formation Of Protective Barrier Research Articles

Natural elicitors enhanced suberin polyphenolic accumulation in wounded potato tuber tissues.

Unintended wounding or bruising during harvest or postharvest handling leads to significant tuber loss and imposes economic burden to potato industry. Therefore, finding effective strategies to mitigate wound-related tuber losses is very important from industry perspectives. Formation of protective barrier through accumulation of suberin polyphenolics (SPP) is a natural and initial response of potato tuber tissues to wounding. In this study, efficacy of two natural elicitors, such as chitosan oligosaccharide (COS 0.125 g L-1) and cranberry pomace residue (Nutri-Cran 0.125 g L-1) was investigated using a mechanically wounded tuber tissue model and by histological determination of SPP formation in five agronomically relevant and red-skin potato cultivars (Chieftain, Dakota Rose, Dakota Ruby, Red LaSoda, Red Norland). Furthermore, the potential role of stress protective metabolic regulation involving phenolic metabolites, proline, and antioxidant enzymes in tuber WH processes were also investigated during 0-9 days after wounding. Exogenous treatments of both COS and Nutri-Cran resulted into enhanced SPP formation in wounded surface, but the impact was more rapid with Nutri-Cran treatment in select cultivars. Greater contents of total soluble phenolic, ferulic acid, chlorogenic acid, total antioxidant activity, and superoxide dismutase activity were also observed in elicitor treated tuber tissues at different time points after wounding. Nutri-Cran treatment also reduced the activity of succinate dehydrogenase in Red Norland and Dakota Ruby at 3 d, indicating a suppression in respiration rate. Collectively, these results suggest that Nutri-Cran can be potentially utilized as an effective WH treatment to potato tubers for minimizing wound-related losses.

Heterogeneity analysis of astrocytes following spinal cord injury at single-cell resolution.

Astrocytes play many important functions in response to spinal cord injury (SCI) in an activated manner, including clearance of necrotic tissue, formation of protective barrier, maintenance of microenvironment balance, interaction with immune cells, and formation of the glial scar. More and more studies have shown that the astrocytes are heterogeneous, such as inflammatory astrocyte 1 (A1) and neuroprotective astrocyte 2 (A2) types. However, the subtypes of astrocyte resulting from SCI have not been clearly defined. In this study, using single-cell RNA sequencing, we constructed the transcriptomic profile of astrocytes from uninjured spinal cord tissue and injured tissue nearby the lesion epicenter at 0.5, 1, 3, 7, 14, 60, and 90 days after mouse hemisection spinal cord surgery. Our analysis uncovered six transcriptionally distinct astrocyte states, including Atp1b2+ , S100a4+ , Gpr84+ , C3+ /G0s2+ , GFAP+ /Tm4sf1+ , and Gss+ /Cryab+ astrocytes. We used these new signatures combined with canonical astrocyte markers to determine the distribution of morphologically and physiologically distinct astrocyte population at injured sites by immunofluorescence staining. Then we identified the dynamic evolution process of each astrocyte subtype following SCI. Finally, we also revealed the evolution of highly expressed genes in these astrocyte subtypes at different phases of SCI. Together, we provided six astrocyte subtypes at single-cell resolution following SCI. These data not only contribute to understand the heterogeneity of astrocytes during SCI but also help to find new astrocyte subtypes as a target for SCI repair.

Preparation and characterization of chitosan films incorporating epigallocatechin gallate: Microstructure, physicochemical, and bioactive properties

Novel chitosan films incorporating epigallocatechin gallate (EGCG) were prepared and demonstrated the ideal physical and mechanical properties required of candidate food packaging materials alongside desirable antioxidant and antibacterial activity. Compared with traditional chitosan films, chitosan films incorporated with EGCG were thicker, had higher tensile strength and water solubility, and had lower elongation at break, moisture content, degree of swelling, and water contact angles. Although EGCG-containing films were slightly darker in color than pure chitosan films, they exhibited a greater inhibitory effect on light-induced oxidation with obviously improved UV–vis barrier capability and opacity. Scanning electron microscopy results suggested that EGCG-incorporated samples had a rougher surface structure. This was further confirmed by atomic force microscopy and indicated that the addition of EGCG facilitated the formation of protective barriers through the interaction between the film and food surface. FTIR spectroscopy confirmed that EGCG interacted with chitosan by intermolecular hydrogen bonding and effectively improved the thermal stability of chitosan films. Notably, the incorporation of EGCG significantly enhanced the antioxidant and antibacterial activity of chitosan films. Hence, chitosan films incorporating EGCG have potential applications in the food industry as a novel active packaging material, especially in preventing food oxidation and spoilage in perishable foods.

Blood-brain barrier genetic disruption leads to protective barrier formation at the Glia Limitans.

Inflammation of the central nervous system (CNS) induces endothelial blood-brain barrier (BBB) opening as well as the formation of a tight junction barrier between reactive astrocytes at the Glia Limitans. We hypothesized that the CNS parenchyma may acquire protection from the reactive astrocytic Glia Limitans not only during neuroinflammation but also when BBB integrity is compromised in the resting state. Previous studies found that astrocyte-derived Sonic hedgehog (SHH) stabilizes the BBB during CNS inflammatory disease, while endothelial-derived desert hedgehog (DHH) is expressed at the BBB under resting conditions. Here, we investigated the effects of endothelial Dhh on the integrity of the BBB and Glia Limitans. We first characterized DHH expression within endothelial cells at the BBB, then demonstrated that DHH is down-regulated during experimental autoimmune encephalomyelitis (EAE). Using a mouse model in which endothelial Dhh is inducibly deleted, we found that endothelial Dhh both opens the BBB via the modulation of forkhead box O1 (FoxO1) transcriptional activity and induces a tight junctional barrier at the Glia Limitans. We confirmed the relevance of this glial barrier system in human multiple sclerosis active lesions. These results provide evidence for the novel concept of "chronic neuroinflammatory tolerance" in which BBB opening in the resting state is sufficient to stimulate a protective barrier at the Glia Limitans that limits the severity of subsequent neuroinflammatory disease. In summary, genetic disruption of the BBB generates endothelial signals that drive the formation under resting conditions of a secondary barrier at the Glia Limitans with protective effects against subsequent CNS inflammation. The concept of a reciprocally regulated CNS double barrier system has implications for treatment strategies in both the acute and chronic phases of multiple sclerosis pathophysiology.

Mineral Trioxide Aggregate Versus Calcium Hydroxide in Direct Pulp Capping: A Review of Literature

Direct pulp-capping is a treatment for exposed vital pulp involving the placement of a dental material over the exposed area. This facilitates both the formation of protective barrier and the maintenance of vital pulp. Direct pulp capping (DPC) has been used as an alternative approach to the maintenance of vital pulp. So, many tooth extractions and root canal treatments could have been avoided through the conservative approach of direct pulp capping. For this purpose, different kinds of materials used such as Zinc Oxide Eugenol, Glass Ionomer (GI), Resin Modified Glass Ionomer (RMGI), Adhesive systems, Calcium Hydroxide (CH), Mineral Trioxide Aggregate (MTA) and Bio dentine. MTA performed more effective than conventional Calcium Hydroxide clinically as a direct pulp capping material. MTA showed higher success rate than dycal. MTA is easier to use clinically as a direct pulp capping material. MTA also provided better long-term results and more effective than Calcium Hydroxide in maintaining long-term vitality. MAT is significantly less toxic, less pulpal inflammations. Furthermore, MTA is more predictable than dycal in formation of dentin barrier and superior than Calcium Hydroxide in dentinogenetic process in human pulp. MTA is more effective and superior comparing the Calcium Hydroxide as a direct pulp capping material, demonstrating higher success rate with favorable outcomes in maintaining long term tooth vitality and easier to use in pulp capping. Finally, MTA is more cost-effective than CH for DPC despite higher initial treatment costs because expensive retreatments were avoided.

Corrosion Protection of A36 Steel with SnO2 Nanoparticles Integrated into SiO2 Coatings

Tin oxide (SnO2) nanoparticles were successfully added to silicon oxide (SiO2) coatings deposited on A36 steel by the sol-gel and dip-coating methods. These coatings were developed to improve the performance of corrosion protection of steel in a 3 wt % NaCl solution. The effects of modifying the SnO2 particle concentration from 0–7.5 vol % were investigated by polarization resistance, Tafel linear polarization, and electrochemical impedance spectroscopy (EIS). The formation of protective barriers and their corrosion inhibition abilities were demonstrated. It was found by electrochemical studies that all of the coated samples presented higher corrosion resistances compared with an uncoated sample, indicating a generally beneficial effect from the incorporation of the nanoparticles. Furthermore, it was established that the relationship between the SnO2 content and the corrosion inhibition had parabolic behaviour, with an optimum SnO2 concentration of 2.5 vol %. EIS showed that the modified coatings improved barrier properties. The resistance for all of the samples was increased compared with the bare steel. The corrosion rate measurements highlighted the corrosion inhibition effect of SnO2 nanoparticles, and the Tafel polarization curves demonstrated a decrease in system dissolution reactions at the optimal nanoparticle concentration.

Comparative study of adsorption of linear aliphatic/aromatic polyesters at metal/0.5 M H2SO4 interface

Two polyesters namely poly (glycerol adipate) (PGA) and 4-(1-(4-methoxyphenyl) cyclohexyl) phenyl 6-oxoheptanoate (MPOHP) were synthesised in a facile manner and characterised using Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic spectroscopy (NMR). The synthesised polyesters were subjected to evaluate the mild steel protecting ability at various concentrations of 10, 50, 100, 500, 1000 ppm in 0.5 M H2SO4 medium. A precise comparison of metal protecting ability rendered by both aliphatic and aromatic moiety was analysed. As an initiation, gravimetric measurements carried out at room temperature resulted with increased inhibition efficiency with increased concentration. Higher temperature studies suggested physisorption mechanism resulting with decreased inhibition efficiency. Experimental results were best fitted with Langmuir adsorption isotherm model. Electrochemical impedance measurements carried out for the selected concentrations of the inhibitors (10, 100, 1000 ppm) revealed increased charge transfer resistance (Rct) with a maximum inhibition efficiency of 54.07% (PGA) and 69.92% (MPOHP) at 1000 ppm indicating the formation of protective barrier. Potentiodynamic polarisation method suggested mixed type of inhibition of both PGA and MPOHP on the metal surface resulting in decreased metal dissolution that could be evidenced from lowered corrosion current density (Icorr).

Influence of phytic acid on the corrosion behavior of carbon steel with different surface treatments

PurposeThis paper aim to investigate the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments, and interpret the inhibition mechanism of PA on the steel with different surface treatments.Design/methodology/approachThe influence of PA on the corrosion behavior of blast cleaned or rusty steel was investigated by means of electrochemical impedance spectroscopy (EIS). The EIS data were analyzed using the @ZsimpWin commercial software. The morphology and component of steel after immersion were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transformation infrared (FTIR) and X-ray diffractometer (XRD).FindingsEIS analysis results indicated that PA had good corrosion inhibition for blast cleaned or rusty steel. SEM, EDS, FTIR and XRD further indicated that PA had two main corrosion inhibition processes for the corrosion inhibition of blast cleaned or rusty steel: corrosion dissolution and formation of protective barrier layers.Originality/valueMost published works focus the attention only toward the effect of corrosion inhibitor for the clean metal surfaces. However, the surface condition of metal sometimes is unsatisfactory in the practical application of corrosion inhibitor, such as existing residual rust. Some studies also have shown that several corrosion inhibitors could be applied on partially rusted substrates. These inhibitors mainly include tannins and phosphoric acid, but not PA. Therefore, the authors investigated the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments in this paper.

Comparative Evaluation of Bioactive Materials and Their Nano-Counterpart as Pulp Capping Agents in Dogs’ Teeth

Introduction: Direct pulp-capping is an alternative procedure to extraction or endodontic therapy, in which a medicament is placed directly over the exposed pulp to maintain pulp vitality and facilitate the formation of protective barrier. Aim of study: The purpose of this study was to evaluate and compare the histological response of dog’s pulp after direct pulp capping with 3 different materials; MTA, Bioactive glass, CEM and their nanoparticles, at 1 month and 3 month time intervals. Materials & Methods: A total of 112 teeth in 8 dogs were used for this study, where 96 teeth were pulp capped with the investigated materials and 16 teeth were serving as negative control. The 14 teeth of each dog were classified into 6 experimental groups and one control (2 teeth each) as follows: Group A: was capped with MTA, Group B: was capped with NMTA, Group C: was capped with CEM, Group D: was capped with NCEM, Group E: was capped with Bioactive glass, Group F: was capped with Nano Bioactive glass and Group G: unprepared tooth (negative control). Dogs were randomly divided into 2 groups (4 dogs each), relative to the observation periods tested, 1 month and 3 months for histomorphological evaluation of pulp response after direct pulp capping with tested materials. Results: Regarding the dentin bridge formation, both NMTA and NCEM groups induced thick dentin bridge with irregular dentin pattern in 1 and 3 months evaluation time period while MTA and CEM induced thinner dentin bridge with regular dentin pattern. BG and NBG groups showed the lowest mean dentin bridge thickness values with no tubular dentin pattern. About the inflammatory reaction of the dental pulp to materials with conventional particle size; MTA displayed the highest prevalence of no inflammation followed by CEM while BG showed the highest prevalence of moderate inflammation and the highest inflammatory cell counts. All nanomaterials showed the highest mean inflammatory cell counts at both evaluations time periods. Conclusion: MTA and CEM can be considered favorable materials for direct pulp capping, while BG and NBG produced the worst inflammatory cell reaction, dentin bridge thickness and quality. Nanoparticles although increased dentin bridge thickness, they also increased the inflammatory cell reaction.

Affinity Based Multilayered Polymeric Self‐Assemblies for Oral Wound Applications

Oral mucositis, a painful and debilitating ulcerative wound condition, is a frequently occurring complication following chemo- and/or radiotherapy. While the current standards of therapy (e.g., gels and mouth rinses) provide temporary relief, there is still an unmet need for a robust, long acting barrier that can provide lubricating protection in oral wounds, thereby enhancing the wound healing response. It is proposed that an affinity based layer-by-layer (LBL) self-assembly that can be administered as a series of mouth rinses could permit the formation of protective barriers, providing a modular approach to regenerative oral therapy. In this study, biotinylated poly(acrylic acid) was synthesized for developing LBL assemblies using biotin-streptavidin affinity linkages. To explore the ability of developed LBL assemblies to potentially resist the harsh intraoral environment, in vitro chemical and ex vivo mechanical tests were performed. The stability results demonstrated significant LBL barrier stability with wear resistance. From statistical analyses, it was deduced that polymer MW and the number of LBL layers contributed significantly to chemical barrier stability. Also, the extent of biotin conjugation played a key role for LBL development and in mechanical barrier stability. Thus, the proposed affinity based LBLs with their excellent barrier properties offer a modular treatment approach in oral mucosal injuries.

Selective Ablation of Ctip2/Bcl11b in Epidermal Keratinocytes Triggers Atopic Dermatitis-Like Skin Inflammatory Responses in Adult Mice

BackgroundCtip2 is crucial for epidermal homeostasis and protective barrier formation in developing mouse embryos. Selective ablation of Ctip2 in epidermis leads to increased transepidermal water loss (TEWL), impaired epidermal proliferation, terminal differentiation, as well as altered lipid composition during development. However, little is known about the role of Ctip2 in skin homeostasis in adult mice.Methodology/Principal FindingsTo study the role of Ctip2 in adult skin homeostasis, we utilized Ctip2ep−/− mouse model in which Ctip2 is selectively deleted in epidermal keratinocytes. Measurement of TEWL, followed by histological, immunohistochemical, and RT-qPCR analyses revealed an important role of Ctip2 in barrier maintenance and in regulating adult skin homeostasis. We demonstrated that keratinocytic ablation of Ctip2 leads to atopic dermatitis (AD)-like skin inflammation, characterized by alopecia, pruritus and scaling, as well as extensive infiltration of immune cells including T lymphocytes, mast cells, and eosinophils. We observed increased expression of T-helper 2 (Th2)-type cytokines and chemokines in the mutant skin, as well as systemic immune responses that share similarity with human AD patients. Furthermore, we discovered that thymic stromal lymphopoietin (TSLP) expression was significantly upregulated in the mutant epidermis as early as postnatal day 1 and ChIP assay revealed that TSLP is likely a direct transcriptional target of Ctip2 in epidermal keratinocytes.Conclusions/SignificanceOur data demonstrated a cell-autonomous role of Ctip2 in barrier maintenance and epidermal homeostasis in adult mice skin. We discovered a crucial non-cell autonomous role of keratinocytic Ctip2 in suppressing skin inflammatory responses by regulating the expression of Th2-type cytokines. It is likely that the epidermal hyperproliferation in the Ctip2-lacking epidermis may be secondary to the compensatory response of the adult epidermis that is defective in barrier functions. Our results establish an initiating role of epidermal TSLP in AD pathogenesis via a novel repressive regulatory mechanism enforced by Ctip2.

Flame retardant phosphorous-containing polymers obtained by chemically modifying poly(vinyl alcohol)

A new set of polymers, which could act as flame retardant additives by blending with “commodity” polymers, was synthesized by chemically modifying poly(vinyl alcohol) (PVA) through reaction with a phosphorous-containing reagent. The phosphorous-based moiety introduced was 1-oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane, which has been reported to be a good flame retardancy promoter structure. For a larger application and better compatibility with thermoplastic polymers, we also introduced in the polymeric additives aliphatic (valeroyl group) or aromatic (benzoyl group) moieties. The structures and properties of the polymers obtained were studied by 1H, 13C and 31P NMR, infrared spectroscopy (FTIR–ATR), inherent viscosity, inductively coupled plasma-atomic emission spectrometry (ICP–AES), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A detailed study of their thermal degradation was performed by thermogravimetry coupled with mass spectrometry (TG–MS) and pyrolysis. Their thermal behavior and high char yield at high temperatures make them promising candidates to act as flame retardant additives through the formation of protective barriers.

Corrosion of silicon nitride materials in acidic and basic solutions and under hydrothermal conditions

Silicon nitride ceramics with different amounts and compositons of the grain boundary phases are produced by gas pressure sintering and the corrosion behaviour was analysed in acids, bases and under hydrothermal conditions. The investigation shows, that the corrosion is strongly affected by the SiO2 content in the grain boundary and the amount of the additives. The results indicate that the grains and the thin films between the grains are very stable in acids and bases but solves partially under hydrothermal conditions. The corrosion behaviour of the investigated materials with a relatively stable grain boundary phase in acids can be described by the same kinetic laws as those used to describe the corrosion of glasses. An interfacial reaction is assumed to be rate-controlling. The less stable material with Y2O3/Al2O3 additives can be described by the corrosion behaviour of oxide nitride glasses only at the beginning. For higher corrosion depths, the formation of protective barriers consisting of a hydrated SiO2 network is assumed to occur.

Réponse du β-glucosyle de l'alcool coniférylique du Pinussylvestris à l'inoculation du Ceratocystisbruneociliata au liber

Inoculation of stems of Pinussylvestris with Ceratocystisbruneociliata leads to a decrease in the concentration of heterosides in inner bark samples collected from the necrotic area. Controls were collected from the trunc side opposite to the inoculated area and from healthy trees. Acidic and enzymatic hydrolysis of the heteroside fraction followed by chromatographic and spectral analyses indicated that the main component of this fraction was β-glucosyl-coniferyl alcohol. The latter product of hydrolysis was also observed in infected tissues. The released glucose may serve as an energy source for defense reactions in which the aglycone could be utilized as a precursor for the production of lignin in the formation of protective barriers or in the direct inhibition of fungus growth.

Protective barrier formation on inner wall of polyethylene pipe by RF plasma coatings

Protective barrier formation on inner wall of polyethylene pipe by RF plasma coatings