Peroxide Treatment Research Articles

Integrated in-package treatment of hydrogen peroxide and cold plasma for microbial inactivation of cabbage slices.

The efficacy of an in-package microbial inactivation method, combining H2O2 and atmospheric dielectric barrier discharge cold plasma (ADCP) treatments (H2O2-ADCP), in reducing contamination of Brassica oleracea (cabbage) slices was investigated. Cabbage slices were placed in a polyethylene terephthalate container with a H2O2-soaked polypropylene pad attached to the inside of the lid, followed by subjecting the closed container to ADCP treatment. The H2O2-ADCP treatment inactivated Escherichia coli O157:H7 and Listeria monocytogenes, resulting in reductions of 1.8 and 2.0 log CFU/g, respectively, which were greater than the sum of the inactivation effects observed with each individual treatment. The combined treatment decreased the count of Bacillus cereus spores and indigenous bacteria by 1.0 log spores/g and 1.3 log CFU/g, respectively. Moreover, the in-package method did not alter the moisture content or texture of cabbage slices. These results demonstrate the potential of H2O2-ADCP as a microbial decontamination method for packaged cabbage slices.

Comparison of genomic DNA sequencing to anerobic cultures to detect efficacy of hydrogen peroxide at reducing cutibacterium acnes bacterial burden during primary shoulder arthroplasty

BackgroundThe purpose of this investigation is to compare Cutibacterium acnes diagnosis using culturing vs. genomic DNA sequencing (NextGen) at various timepoints and locations during primary total shoulder arthroplasty. Additionally, we intend to compare the effects of hydrogen peroxide on standard culture technique results with genomic DNA sequencing. MethodsA prospective diagnostic study of 40 patients undergoing primary total shoulder arthroplasty was performed. Intraoperatively, 4 tissue samples were collected per patient: subdermal skin edge following initial skin incision, subdermal skin edge following hydrogen peroxide soak for 5 minutes, glenohumeral joint capsule, and subdermal skin edge prior to wound closure. Each tissue specimen was collected twice (one for culture analysis and the other for genomic (NextGen) DNA sequencing analysis) for a total of 8 specimens per patient and 320 tissue specimens in total. All anaerobic cultures were held for 14 days. Each culture plate was divided into quadrants and the amount of growth was quantified. Tissue samples were collected for genomic sequencing DNA analysis. Genomic sequencing results provided relative percentage of bacteria for each specimen detected. ResultsThere were 18/40 males (45%) and no postoperative complications. Average age was 72.2 ± 11.8. Overall, 18% (29/160) of standard anaerobic cultures were positive for C. Acnes and 26% (942/160) were positive with genomic (Nextgen) DNA sequencing. When comparing the NextGen results with anaerobic standard cultures, there was a calculated negative predictive value of 85.6% and positive predictive value of 28.6%. Sensitivity of the NextGen was 41.4% and specificity was 77.1%. Bacterial culture rates did not significantly change from the beginning to the end of surgery as demonstrated on standard culturing and the NextGen analysis (P > .05). After treatment with hydrogen peroxide, the standard culturing technique showed no significant difference between the samples; however, there was a significant increase in bacterial burden (12.4%) noted with NextGen analysis (P = .0147). ConclusionNextGen culturing is a novel technique to help identify shoulder prosthetic joint infections. These results show that, NextGen is better at identifying the absence of infection, but has a high false positive rate indicative of its ability to identify contaminants as compared to standard anaerobic culturing methods. The increase in bacterial burden after peroxide treatment noted with NextGen could also be secondary to the test’s increased ability to identify both living and dead bacterial pathogens.

Comprehensive Transcriptome Profiling of Antioxidant Activities by Glutathione in Human HepG2 Cells.

Glutathione (GSH) has long been recognised for its antioxidant and detoxifying effects on the liver. The hepatoprotective effect of GSH involves the activation of antioxidative systems such as NRF2; however, details of the mechanisms remain limited. A comparative analysis of the biological events regulated by GSH under physiological and oxidative stress conditions has also not been reported. In this study, DNA microarray analysis was performed with four experiment arms including Control, GSH, hydrogen peroxide (HP), and GSH + HP treatment groups. The GSH-treated group exhibited a significant upregulation of genes clustered in cell proliferation, growth, and differentiation, particularly those related to MAPK, when compared with the Control group. Additionally, liver functions such as alcohol and cholesterol metabolic processes were significantly upregulated. On the other hand, in the HP-induced oxidative stress condition, GSH (GSH + HP group) demonstrated a significant activation of cell proliferation, cell cycle, and various signalling pathways (including TGFβ, MAPK, PI3K/AKT, and HIF-1) in comparison to the HP group. Furthermore, several disease-related pathways, such as chemical carcinogenesis-reactive oxygen species and fibrosis, were significantly downregulated in the GSH + HP group compared to the HP group. Collectively, our study provides a comprehensive analysis of the effects of GSH under both physiological and oxidative stress conditions. Our study provides essential insights to direct the utilisation of GSH as a supplement in the management of conditions associated with oxidative stress.

Excess secondary sludge reuse by H2O2 thermal dehydration

The excess of activated sludge generated in municipal wastewater treatment plants constitutes one of the challenging problems facing modern society. The high-water content of this waste makes difficult the transport, disposal, and management of these solids. In this work, activated sludge excess from a secondary clarifier has been dehydrated by means of a combination of temperature and hydrogen peroxide treatment. Three main operating variables have been considered to affect sludge dewaterability and filterability. Temperature (120–180 °C), hydrogen peroxide dose (0.01–0.03 M), and treatment time (20–60 min) influence have been assessed by completing a 15-run Box Behnken experimental design. Different output variables (water content, resistance to filtration, sedimentation volumetric index, extracellular polymeric substances, etc.) have been monitored. Generally, temperature seems to be the most influencing parameter to obtain a dehydrated sludge with acceptable management/disposal characteristics (sludge volume reduction and filterability). In line with the concept of circular economy, an attempt has been conducted to obtain a sustainable biosorbent from the dehydrated sludge generated in the previous stage. Optimum conditions of carbonization and activation revealed that the solid obtained at 400 °C by using ammonium nitrate as activation agent was the most efficient absorbent to eliminate some model compounds from water (namely, phenol, ofloxacin, and diuron); however, a clear improvement margin in the synthesis is foreseen.

Bacterial community shifts induced by high concentration hydrogen peroxide treatment of Microcystis bloom in a mesocosm study

Hydrogen peroxide has gained popularity as an environmentally friendly treatment for cyanobacterial harmful algal blooms (cHABs) that takes advantage of oxidative stress sensitivity in cyanobacteria at controlled concentrations. Higher concentrations of hydrogen peroxide treatments may seem appealing for more severe cHABs but there is currently little understanding of the environmental impacts of this approach. Of specific concern is the associated microbial community, which may play key roles in the succession/recovery process post-treatment. To better understand impacts of a high concentration treatment on non-target microbial communities, we applied a hydrogen peroxide spray equating to a total volume concentration of 14 mM (473 mg/L, 0.04%) to 250 L mesocosms containing Microcystis bloom biomass, monitoring treatment and control mesocosms for 4 days. Cyanobacteria dominated control mesocosms throughout the experiment while treatment mesocosms experienced a 99% reduction, as determined by bacterial amplicon sequencing, and a 92% reduction in bacterial cell density within 1 day post-treatment. Only the bacterial community exhibited signs of regrowth, with a fold change of 9.2 bacterial cell density from day 1 to day 2. Recovery consisted of succession by Planctomycetota (47%) and Gammaproteobacteria (17%), which were likely resilient due to passive cell component compartmentalization and rapid upregulation of dnaK and groEL oxidative stress genes, respectively. The altered microbiome retained beneficial functionality of microcystin degradation through a currently recognized but unidentified pathway in Gammaproteobacteria, resulting in a 70% reduction coinciding with bacterial regrowth. There was also an 81% reduction of both total nitrogen and phosphorus, as compared to 91 and 93% in the control, respectively, due to high expressions of genes related to nitrogen (argH, carB, glts, glnA) and phosphorus (pntAB, phoB, pstSCB) cycling. Overall, we found a portion of the bacterial community was resilient to the high-concentration hydrogen peroxide treatment, resulting in Planctomycetota and Gammaproteobacteria dominance. This high-concentration treatment may be suitable to rapidly end cHABs which have already negatively impacted the aquatic environment rather than allow them to persist.

Synechococcus dominance induced after hydrogen peroxide treatment of Microcystis bloom in the Caloosahatchee River, Florida

Few field trials examining hydrogen peroxide as a cyanobacterial harmful algal bloom (cHAB) treatment have been conducted in subtropical and tropical regions. None have been tested in Florida, home to Lake Okeechobee and downstream waterways which periodically experience Microcystis bloom events. To investigate treatment effects in Florida, we applied a 490 μM (16.7 mg/L; 0.0015%) hydrogen peroxide spray to a minor bloom of Microcystis aeruginosa on the downstream side of Franklin Lock and Dam in the Caloosahatchee River. Although hydrogen peroxide decreased to background level one day post-treatment, succession was observed in phytoplankton community amplicon sequencing. The relative abundance of Microcystis decreased on day 3 by 86%, whereas the picocyanobacteria Synechococcus became dominant, increasing by 77% on day 3 and by 173% on day 14 to 57% of the phytoplankton community. Metatranscriptomics revealed Synechococcus likely benefitted from the antioxidant defense of upregulated peroxiredoxin, peroxidase/catalase, and rubrerythrin expressions immediately after treatment, and upregulated nitrate transport and urease to take advantage of available nitrogen. Our results indicated hydrogen peroxide induces succession of the phytoplankton community from Microcystis to non-toxic picocyanobacteria and could be used for selective suppression of harmful cyanobacteria.

The Transposition of Insertion Sequences in Sigma-Factor- and LysR-Deficient Mutants of Deinococcus geothermalis.

Some insertion sequence (IS) elements were actively transposed using oxidative stress conditions, including gamma irradiation and hydrogen peroxide treatment, in Deinococcus geothermalis, a radiation-resistant bacterium. D. geothermalis wild-type (WT), sigma factor gene-disrupted (∆dgeo_0606), and LysR gene-disrupted (∆dgeo_1692) mutants were examined for IS induction that resulted in non-pigmented colonies after gamma irradiation (5 kGy) exposure. The loss of pigmentation occurred because dgeo_0524, which encodes a phytoene desaturase in the carotenoid pathway, was disrupted by the transposition of IS elements. The types and loci of the IS elements were identified as ISDge2 and ISDge6 in the ∆dgeo_0606 mutant and ISDge5 and ISDge7 in the ∆dgeo_1692 mutant, but were not identified in the WT strain. Furthermore, 80 and 100 mM H2O2 treatments induced different transpositions of IS elements in ∆dgeo_0606 (ISDge5, ISDge6, and ISDge7) and WT (ISDge6). However, no IS transposition was observed in the ∆dgeo_1692 mutant. The complementary strain of the ∆dgeo_0606 mutation showed recovery effects in the viability assay; however, the growth-delayed curve did not return because the neighboring gene dgeo_0607 was overexpressed, probably acting as an anti-sigma factor. The expression levels of certain transposases, recognized as pivotal contributors to IS transposition, did not precisely correlate with active transposition in varying oxidation environments. Nevertheless, these findings suggest that specific IS elements integrated into dgeo_0524 in a target-gene-deficient and oxidation-source-dependent manner.

Mechanistic interpretation of the sorption of terbuthylazine pesticide onto aged microplastics

Microplastics (MPs) pose a global concern due to their ubiquitous distribution. Once in the environment, they are subject to aging, which changes their chemical-physical properties and ability to interact with organic pollutants, such as pesticides. Therefore, this study investigated the interaction of the hydrophobic herbicide terbuthylazine (TBA), which is widely used in agriculture, with artificially aged polyethylene (PE) MP (PE-MP) to understand how aging affects its sorption. PE was aged by an accelerated weathering process including UV irradiation, hydrogen peroxide, and ultrasonic treatment, and aged particles were characterized in comparison to pristine particles. Sorption kinetics were performed for aged and pristine materials, while further sorption studies with aged PE-MP included determining environmental factors such as pH, temperature, and TBA concentration. Sorption of TBA was found to be significantly lower on aged PE-MP compared to pristine particles because aging led to the formation of oxygen-containing functional groups, resulting in a reduction in hydrophobicity and the formation of negatively charged sites on oxidized surfaces. For pristine PE-MP, sorption kinetics were best described by the pseudo-second-order model, while it was intra-particle diffusion for aged PE-MP as a result of crack and pore formation. Sorption followed a decreasing trend with increasing pH, while it became less favorable at higher temperatures. The isotherm data revealed a complex sorption process on altered, heterogeneous surfaces involving hydrophobic interactions, hydrogen bonding, and π-π interactions, and the process was best described by the Sips adsorption isotherm model. Desorption was found to be low, confirming a strong interaction. However, thermodynamic results imply that increased temperatures, such as those resulting from climate change, could promote the re-release of TBA from aged PE-MP into the environment. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) confirmed TBA sorption onto PE.

Physicochemical Treatments of Graphene Oxide to Improve Water Vapor/Gas Separation Performance of Supported Laminar Membranes: Sonication and H2O2 Oxidation.

We investigated the previously unexplored domain of water vapor/gas separation using graphene oxide (GO) membranes, expecting future applications, including gas dehumidifiers and superior humidity controllers. While the importance of manipulation of GO nanosheet size and surface chemistry in traditional water purification and gas separation has been acknowledged, their potential impact on water vapor/gas separation remained unexplored until now. We applied sonication and hydrogen peroxide treatments to GO water dispersions and systematically evaluated the size and surface chemistry of each GO nanosheet. Both treatments reduced the GO nanosheet size to shorten the diffusion length, which improved water permeance. In addition, hydrogen peroxide treatment improved the hydrophilicity of the nanosheet. Our novel findings demonstrate that optimization of GO nanosheet size and the increase in their hydrophilicity via hydrogen peroxide treatments for 5 h significantly enhance water permeance, leading to a remarkable water vapor permeance of 4.6 × 10-6 mol/(m2 s Pa) at 80 °C, a 3.1-fold improvement over original GO membranes, while maintaining a water vapor/nitrogen permeance ratio exceeding 10,000. These results not only provide important insights into the nature of water vapor/gas separation but also suggest innovative methods for optimizing the GO membrane structure.

Detoxification and enhancement of in vitro rumen digestibility of exhausted olive pomace wastes through alkaline hydrogen peroxide treatment

Abstract Background Due to the sharp rise in animal feed costs, funding alternatives to substitute high-cost raw materials used in animal feed is a persistent need. This study investigated the effect of alkaline hydrogen peroxide pretreatment as straightforward non-toxic technology to enhance the in vitro rumen digestibility of exhausted olive pomace (EOP), an abundant agricultural waste, to be suitable as animal feedstock. It examined the efficiency to eliminate the toxic phenolic content and minimize lipid oxidation of EOP. Results The pretreatment was first optimized using a central composite experimental design. Under the optimized conditions (1.6% H2O2, 5% NaOH), the measured phenolic content was 1.51 ± 0.03 mg/100 g dry weight (DW) for treated olive pomace (TOP) versus 4.91 ± 0.06 mg/100 g for the untreated one. The pretreatment showed that approximately 25% of the lignin was removed. Crude proteins, neutral detergent fibers, and acid detergent fibers yields of TOP were, respectively, 3.320 ± 0.05, 75.24 ± 0.23, and 54.05 ± 0.35 g/100 g of DW, significantly more important than those of untreated EOP. The enzymatic hydrolysis with a cellulase-based cocktail (Celluclast15 FPU/gDW), recorded a 48% of reducing sugar yield for TOP against 33% for EOP. When the in vitro organic matter digestibility (IVOMD) was assayed, the potential gas production of TOP (41.371 ml/g DM) was significantly higher than EOP (25.771 ml/g DM). The metabolizable energy of TOP (9.28 kcal/kg DM) was higher than that of EOP (7.78 kcal/kg DM). Conclusions The present study revealed that alkaline hydrogen peroxide (AHP) could be an efficient treatment for the detoxification and enhancement of in vitro rumen digestibility of olive pomace. This straightforward approach demonstrated that treated olive pomace waste may be well valorized as suitable animal feedstock. Graphical Abstract

OsUGE2 Regulates Plant Growth through Affecting ROS Homeostasis and Iron Level in Rice

BackgroundThe growth and development of rice (Oryza sativa L.) are affected by multiple factors, such as ROS homeostasis and utilization of iron. Here, we demonstrate that OsUGE2, a gene encoding a UDP-glucose 4-epimerase, controls growth and development by regulating reactive oxygen species (ROS) and iron (Fe) level in rice. Knockout of this gene resulted in impaired growth, such as dwarf phenotype, weakened root growth and pale yellow leaves. Biochemical analysis showed that loss of function of OsUGE2 significantly altered the proportion and content of UDP-Glucose (UDP-Glc) and UDP-Galactose (UDP-Gal). Cellular observation indicates that the impaired growth may result from decreased cell length. More importantly, RNA-sequencing analysis showed that knockout of OsUGE2 significantly influenced the expression of genes related to oxidoreductase process and iron ion homeostasis. Consistently, the content of ROS and Fe are significantly decreased in OsUGE2 knockout mutant. Furthermore, knockout mutants of OsUGE2 are insensitive to both Fe deficiency and hydrogen peroxide (H2O2) treatment, which further confirmed that OsUGE2 control rice growth possibly through Fe and H2O2 signal. Collectively, these results reveal a new pathway that OsUGE2 could affect growth and development via influencing ROS homeostasis and Fe level in rice.

Effect of carbon encapsulation on magnetic inter-particle interaction of iron nanoparticles

Carbon encapsulation of magnetic nanoparticles reduces agglomeration and makes the nanoparticles stable. In this work, as-prepared carbon-coated iron nanoparticles (CCFeNPs) are treated with hydrogen peroxide (H2O2) solution, and the effect of carbon coating on the interparticle interaction of iron nanoparticles is discussed. Morphological characterization and the magnetization data confirmed that the treatment removes some coating layers. Field cooled (FC) and zero-field cooled (ZFC) measurements on the two samples revealed that the blocking temperature (TB) of the treated sample is lowered post hydrogen peroxide treatment. Magnetic interaction is increased in the treated sample compared to the as-prepared one and follows the Morup–Tronc (MT) model of inter-particle interactions (IPI). MR/MS ratio decreases post-treatment, indicating an increase in IPI after treatment. Out-of-phase AC susceptibility data showed two slope changes; one at a higher temperature indicates the magnetic blocking of core Fe, and the other at a lower temperature with a broad peak that shifts with frequency due to spin-glass behavior in the system.

The effects of heat and hydrogen peroxide treatment on the osteoinductivity of demineralized cortical bone: a potential method for preparing tendon/ligament repair scaffolds.

Recent studies have indicated that demineralized cortical bone (DCB) may be used to repair tendons and ligaments, such as the patellar tendon and anterior cruciate ligament (ACL). Hydrogen peroxide (H2O2) has been shown to reduce the osteoinductivity of DCB, and heat treatment may also decrease the osteoinductivity of DCB. The purpose of this study was (i) to determine whether heat treatment reduces the osteoinductivity of DCB and (ii) to compare the effectiveness of heat treatment and H2O2 treatment on BMP-2 inactivation. DCB was prepared by immersion in 0.6 N hydrochloric acid, and DCB-H and DCB-HO were prepared by heat treatment (70°C for 8 h) and H2O2 treatment (3% H2O2 for 8 h), respectively. The surface topographies, elemental distributions and histological structures of the scaffolds were observed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and histological staining. The viability and osteogenic differentiation of TDSCs cultured on the scaffolds were evaluated via live/dead cell staining and Cell Counting Kit-8 (CCK-8) testing, real-time polymerase chain reaction (RT-PCR) and western bolt (WB) analysis, alkaline phosphatase activity (ALP) and alizarin red S (ARS) staining. The intramuscular implantation of the scaffolds in rats was also used to evaluate the effect of heat treatment and H2O2 treatment on the osteoinductivity of DCB. Our results demonstrated that both treatments removed BMP-2 and osteocalcin (OCN) within the DCB and that DCB-H and DCB-HO had good cytocompatibility and reduced the osteogenic differentiation of TDSCs. Moreover, the in vivo results indicated that the DCB-H and DCB-HO groups had smaller areas of osteoid formation than did the DCB group, and the DCB-HO group had the smallest area among the three groups. Our study demonstrated that heat treatment could reduce the osteoinductivity of DCB, and that H2O2 treatment was more effective than heat treatment.

Preparation of a novel antibacterial magnesium carbonate coating on a titanium surface and its in vitro biocompatibility.

Magnesium-based coatings have attracted great attention in surface modification of titanium implants due to their superior angiogenic and osteogenic properties. However, their biological effects as a carbonate-based constituent remain unrevealed. In this study, magnesium carbonate coatings were prepared on titanium surfaces under hydrothermal conditions and subsequently treated with hydrogen peroxide. Also, their antibacterial activity and in vitro cell biocompatibility were evaluated. The obtained coatings consisted of nanoparticles without cracks and exhibited excellent adhesion to the substrate. X-ray diffraction (XRD) results indicated pure magnesium carbonate coatings formed on the Ti surface after hydrothermal treatment. After hydrogen peroxide treatment, the phase composition of the coatings had no obvious change. Compared to the untreated coatings, the hydrogen peroxide-treated coatings showed increased surface roughness and hydrophilicity. Co-culture with Staphylococcus aureus (S. aureus) demonstrated that the obtained coatings had good antibacterial activity. In vitro cell culture results showed that the hydrogen peroxide-treated coatings enhanced the viability, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). These findings suggest that this MgCO3-based coating exhibits excellent antibacterial performance and osteogenic potential. Based on the above, this study provides a simple method for preparing titanium implants with dual antibacterial and osteogenic capabilities, holding great promise in clinical applications.

The effect of hydrogen peroxide treatment on functional properties of paddy husk biochar and its application for wastewater treatment

Paddy husk is one of the biomass raw materials and byproducts of the rice production and processing industry. It is very much abundant in Sri Lanka, which is readily available as an energy source. Paddy husk contains silica as a special characteristic component. Application of paddy husk is novel in Sri Lanka. Though it has perceived implications, the process may impose limitations in its application. Appropriate knowledge of the functional properties of paddy husk is required for applying them in thermochemical conversion processes like pyrolysis. The ultimate objective of this study is to identify the effectiveness of wastewater treatment using biochar, derived from H2O2-treated paddy husk. The changes in functional properties: moisture content, proximate analysis, true density, bulk density, and porosity of paddy husks, before and after H2O2 treatment were evaluated in this study. Two main variables: concentration of H2O2 and treatment temperature, were considered. The H2O2 treatment method was investigated to remove the lignin distributed in the lignocellulosic matrix of paddy husk. The results obtained from this experimental study showed that there was a significant difference in the functional properties of the paddy husk after H2O2 treatment. The biosorbent adsorption process is the finest treatment method, for the removal of methylene blue dye. The use of H2O2-treated paddy husk bio sorbent as an alternative cost-effective adsorbent in the removal of methylene blue has been extensively studied and compiled. Biochar as a firm carbonaceous material shows reasonable potential to oversee wastewater contaminants, due to induced pore spaces that are responsible for the removal of contaminants.

Characterization of clay and nanoclay extracted from a semi-arid Vertisol and investigation of their carbon sequestration potential.

Mitigation of global climate change by means such as soil carbon (C) sequestration has become an important area of research. Soil organic matter (SOM) that is stabilized with clay minerals is the most persistent in soils. Currently, little is known regarding the C sequestration ability of nanoclay extracted from Vertisols in semi-arid regions. Therefore, the aim of this study was to extract and characterize nanoclay and bulk clay from a Vertisol from Iran, in terms of physicochemical surface properties and resistance of SOM to chemical oxidation. The clay fractions were studied before and after H2O2 treatment by total C analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), pyrolysis gas chromatography mass spectrometry (GC-MS), Fourier transform infrared (FTIR) spectroscopy, specific surface area analysis, and zeta potential. TEM and SEM images showed that the diameter of the extracted nanoclays was 16-46nm and their morphology was more porous than bulk soil clay. The nanoclay had a much greater specific surface area (111.9 m2g-1) than the bulk clay (67.9 m2g-1). According to total C, FTIR, and zeta potential results, the nanoclay was enriched with 1.4 times more C than the bulk clay after peroxide treatment, indicating enhanced soil C stabilization in the nanoclay. About 45% of the peroxide-resistant SOM in the nanoclay was associated with N-containing compounds, indicating that these compounds contribute to SOM stability. The results demonstrate important role of nanoclay in soil C sequestration in Vertisols.

Effects of Fiber Treatment and Humidity on the Mechanical, Fracture Toughness, Dynamic and Thermal Properties of Grewia Optiva Natural Fiber Reinforced Epoxy Composites

Abstract The effects of relative humidity, and fiber treatment on the mechanical properties of Grewia Optiva natural fibres reinforced composites were studied. The results revealed that the fiber reinforcement composition with Benzoyl peroxide treatment on NaOH pretreated fiber (BP) shows optimum results at 90% relative humidity. The corresponding experimental results of the tensile strength (MPa), % elongation, flexural strength (MPa), impact strength (kJ/m2), and fracture toughness (MPa vm) were 260.895, 5.230, 52.572, 33.226, and 2.565 respectively. The surface response method yielded the optimum properties with D value as 0.768 and properties variation between 1 to 6%. TGA analysis shows a considerable amount of variation in the rate of degradation after the chemical treatment of fibers. Decrease in the damping factor and increase in glass transition temperature due to chemical treatment shows increased fiber matrix interfacial bonding and cross linking. SEM images show that BP treatment is more suitable than NaOH treatment to remove the undesirable elements from the fiber surface and higher surface roughness to obtain better bonding between fibre and matrix. The fiber diameter reduction due to BP and NaOH treatment is about 57 %, and 52.62 % as compared to untreated fiber.

Efficient Production of Succinic Acid from Sugarcane Bagasse Hydrolysate by Actinobacillus succinogenes GXAS137

Sugarcane bagasse (SCB) is an abundant agricultural waste, rich in cellulose and hemicellulose, that could be used as an ideal raw material for succinic acid (SA) production. A two-step chemical pretreatment, involving alkali extraction and alkaline hydrogen peroxide treatment, was utilized to treat SCB, followed by multi-enzyme hydrolysis to obtain a reducing sugar hydrolysate mainly composed of glucose and xylose. Optimization of the multi-enzyme hydrolysis of pretreated SCB resulted in a final reducing sugar concentration of 78.34 g/L. In order to enhance the bioconversion of SCB to SA and to reduce the production costs, the initial reducing sugar concentration, nitrogen source, and MgCO3 content were further optimized. The results demonstrated that the inexpensive corn steep liquor powder (CSLP) could be utilized as an alternative nitrogen source to yeast extract for the production of SA; and the optimal concentrations of initial reducing sugar, CSLP, and MgCO3 were 70 g/L, 18 g/L, and 60 g/L, respectively. When fed-batch fermentation was conducted in a 2 L stirred bioreactor, approximately 72.9 g/L of SA was produced, with a yield of 83.2% and a productivity of 1.40 g/L/h. The high SA concentration, yield, and productivity achieved in this study demonstrate the potential of SCB, an agricultural waste, as a viable alternative substrate for Actinobacillus succinogenes GXAS137 to produce SA. This lays a solid foundation for the resource utilization of agricultural waste and cost-effective industrial-scale production of SA in the future.

SmRAV1, an AP2 and B3 Transcription Factor, Positively Regulates Eggplant's Response to Salt Stress.

Salt stress is a lethal abiotic stress threatening global food security on a consistent basis. In this study, we identified an AP2 and B3 domain-containing transcription factor (TF) named SmRAV1, and its expression levels were significantly up-regulated by NaCl, abscisic acid (ABA), and hydrogen peroxide (H2O2) treatment. High expression of SmRAV1 was observed in the roots and sepal of mature plants. The transient expression assay in Nicotiana benthamiana leaves revealed that SmRAV1 was localized in the nucleus. Silencing of SmRAV1 via virus-induced gene silencing (VIGS) decreased the tolerance of eggplant to salt stress. Significant down-regulation of salt stress marker genes, including SmGSTU10 and SmNCED1, was observed. Additionally, increased H2O2 content and decreased catalase (CAT) enzyme activity were recorded in the SmRAV1-silenced plants compared to the TRV:00 plants. Our findings elucidate the functions of SmRAV1 and provide opportunities for generating salt-tolerant lines of eggplant.

NDRG2 alleviates photoreceptor apoptosis by regulating the STAT3/TIMP3/MMP pathway in mice with retinal degenerative disease.

Photoreceptor apoptosis is the main pathological feature of retinal degenerative diseases; however, the underlying molecular mechanism has not been elucidated. Recent studies have shown that N-myc downstream regulated gene 2 (NDRG2) exerts a neuroprotective effect on the brain and spinal cord. In addition, our previous studies have confirmed that NDRG2 is expressed in mouse retinal photoreceptors and counteracts N-methyl-N-nitrosourea (MNU)-induced apoptosis. However, the underlying molecular mechanism remains unclear. In this study, we observed that the expression of NDRG2 was not only significantly inhibited in photoreceptors after MNU treatment but also after hydrogen peroxide treatment, and photoreceptor apoptosis was alleviated or aggravated after overexpression or knockdown of NDRG2 in the 661W photoreceptor cell line, respectively. The apoptosis inhibitor Z-VAD-FMK rescued photoreceptor apoptosis induced by MNU after NDRG2 knockdown. Next, we screened and identified tissue inhibitor of metalloproteinases 3 (TIMP3) as the downstream molecule of NDRG2 in 661W cells by using quantitative real-time polymerase chain reaction. TIMP3 exerts a neuroprotective effect by inhibiting the expression of matrix metalloproteinases (MMPs). Subsequently, we found that signal transducer and activator of transcription 3 (STAT3) mediated the NDRG2-associated regulation of TIMP3. Finally, we overexpressed NDRG2 in mouse retinal tissues by intravitreally injecting an adeno-associated virus with mouse NDRG2 in vivo. Results showed that NDRG2 upregulated the expression of phospho-STAT3 (p-STAT3) and TIMP3, while suppressing MNU-induced photoreceptor apoptosis and MMP expression. Our findings revealed how NDRG2 regulates the STAT3/TIMP3/MMP pathway and uncovered the molecular mechanism underlying its neuroprotective effect on mouse retinal photoreceptors.