Pure Chemicals Research Articles

Corrosion Inhibition of Carbon Steel By Inert Gas Ultrafine Bubbles

The Fukushima Daiichi Nuclear Power Plant experienced power loss in Units 1-4 due to the Great East Japan Earthquake on March 11, 2011, causing the shutdown of the fuel cooling systems for the reactor cores and spent fuel pools. Consequently, the reactor buildings suffered damage from core meltdowns and hydrogen explosions, releasing radioactive materials. During this incident, fuel debris accumulated within the reactor. Currently, efforts are made to minimize corrosion inside the reactor by maintaining low dissolved oxygen concentration underwater through degassing treatment of circulating water for fuel debris cooling and nitrogen injection into the Primary Containment Vessel (PCV) to prevent hydrogen explosions. However, future fuel debris retrieval operations may expose the PCV to the atmosphere temporarily, raising concerns about increased dissolved oxygen concentration, inducing acceleration of corrosion reaction. Hence, it is necessary to establish corrosion inhibition techniques resilient to radiolysis, as an alternative to nitrogen injection. Utilization of inert gas ultrafine bubbles (UFB) are anticipated to effectively reduce dissolved oxygen in water. Therefore, in this study, effects of the argon gas UFB introduction treatment on corrosion reaction of carbon steel in a simulated reactor environment (without radioactive material) were evaluated to explore methods for effectively inhibiting corrosion reactions during fuel debris retrieval.The round-shaped carbon steel (SM490A) specimen mounted in epoxy resin was used as corrosion-monitoring sensor electrode. Two types of electrodes were prepared: immediately after polishing and rust-formed. The latter electrode was prepared by accelerating corrosion reaction using a saltwater spray testing machine (STP-30, Suga Testing Machine, 50 gL-1 NaCl solution at 303K) for three days to induce the thick rust layer formation on the surface.A solution of artificial seawater (Aquamarine, Yashima Pure Chemicals, Japan) diluted 200-fold was employed for the simulated reactor environment. UFB introduction treatment was conducted for 10 liters of the solution using an ultrafine bubble generation machine (BUVITAS, NEXCO Engineering Kansai, Japan) with Ar gas flowing at a rate of 650 mL/min for 30 minutes. The aerated (open air condition) test solution without UFB introduction treatment was also prepared for comparison. To prevent overheating the solution during the treatment, an immersion cooler (BE201F, Yamato Scientific, Japan) was used. It was confirmed that the solution temperature could be kept below 25°C even after 30 minutes of the UFB-introduction treatment by cooling the solution to 5°C in advance. A glass water vessel with a cubic shape (15 cm × 15 cm × 15 cm) was used as electrochemical cell, and it was completely sealed inside a larger 20 L plastic container directly connected to the UFB-generation machine. A drainage trap was installed to prevent the backflow of oxygen from the atmosphere during the solution discharging process. Pairs of the electrodes were placed facing each other with distance of 1 cm. These steel electrodes for corrosion monitoring were fixed at the bottom of the cell. The measurements were conducted in the following manner. Before pouring the solution inside the cell, Ar gas purging for 30 minutes was performed in advance to eliminate the effect of residual oxygen in the container. The corrosion rate was evaluated by simplified electrochemical impedance spectroscopy using corrosion monitor (CT-7, Riken Densi, Japan).The dissolved oxygen (DO) concentration during UFB introduction treatment decreased rapidly from the beginning of the treatment and reached nearly 0 ppm within a few minutes.The corrosion rate of carbon steel without rust layer in with UFB condition remained stable and was kept lower value than that without UFB condition during testing period of 6 d. Thus, it was considered that the initial corrosion reaction of carbon steel in diluted seawater environment was effectively inhibited by the presence of UFB with lower DO concentration.In the case of the rust-formed specimen, the corrosion rates were nearly an order of magnitude higher than those of the specimens without rust layer. The corrosion rate tended to decrease in the UFB-introduced solution. On the other hand, it exhibited a clear increasing tendency under the UFB-free condition.These results clearly demonstrate that the introduction of Ar gas UFB effectively suppresses corrosion of carbon steel in diluted seawater, regardless of the presence of rust layer.It has been demonstrated that the introduction of ultrafine bubbles (UFB) using inert gas effectively reduces the dissolved oxygen (DO) concentration in the solution for longer period. In addition, , corrosion inhibition effect due to low DO condition was found to be available regardless of the presence of rust layer formed on carbon steel surface in advance.

Measuring the purity of organic chemicals: general approaches and development of an appropriate procedure for research of pure organic chemicals

Pure materials are in demand in many sectors of the national economy, including the metrological service. High purity organic material is the ultimate source of metrological traceability in organic analysis to the basic units of the International System of Units (SI). This article presents the general approaches to determining the mass fraction of the main component in pure organic chemicals, which provide a traceable connection between the certified value of substance purity and the basic SI units - mass (kilogram) and amount of substance (mole), the features of using direct and indirect measurement approaches are considered, specific analytical methods that can be used for this purpose are discussed. Determining the purity of an organic material in most cases is not a plain analytical and metrological task. Solving this issue requires the relevant instrumental methods and appropriate measurement procedure, which is able to provide a comprehensive study of organic matter and guarantee the necessary accuracy of the certified value. Taking in consideration the vast diversity of organic chemicals, the determination of the purity of organic substances will never be a standardized procedure.

Synthesis of aluminosilicate mesoporous material MSU-S from natural resources: Investigating the effects on the structure formation

Zeolite seed-based mesoporous aluminosilicate material MSU-S is normally synthesized from pure chemicals. In the study, MSU-S material was synthesized using natural resources such as rice husk, and kaolin in Vietnam. Here, a systematic investigation is conducted to find the relationship between the synthesis conditions (aging time, hydrothermal time, hydrothermal temperature, pH environment) and the formation of mesoporous structure, as well as the material properties. The sample was characterized by XRD, TEM, N2 adsorption-desorption isotherms, and TGA-DSC. The MSU-S material has been synthesized successfully from rice husk and kaolin. The best conditions are aging time of 24 hours, and hydrothermal conditions at 95 oC during 96 hours with pH=9. The MSU-S has an ordered hexagonal mesoporous structure containing zeolite BEA seed. The pore diameter is concentrated at 2.9 nm. The BET surface area is calculated to be 770 m²/g. Thermal stability is determined to be up to 900 oC.

Isolation, Characterization and In-silico screening of compounds from Ziziphus rugosa bark for their Antiulcer effect

To explore the interaction of compounds isolated from Ziziphus rugosa (Rahmnaceae) with human Histamine H2 and H/K+ ATPase receptor proteins for In-silico antiulcer activity the present study was performed. Because of the exceptional availability of phytoconstituents as pure chemicals in natural products or standardised extracts, the possibilities for innovative drug development are nearly limitless. Ziziphus rugosa (Rahmnaceae) is one of the traditional medicinal plant used in treatment of various ailments and the ethanolic extract of its bark is reported to have antiulcer activity. Four compounds were isolated form the ethanolic extract of bark to explore the interaction of isolated compounds with human Histamine H2 and H/K+ ATPase receptor proteins. We performed molecular docking studies using AutoDock4.2, non-targeted and local docking approaches were employed for the binding mode and interaction study of antiulcer compounds. From the results, Ligand [(4-[(E)-2-(5-ethyl-7-hydroxyquinazolin-2-yl) ethenyl]-2-methyl cyclohexane-1-carboxylic acid] showed binding affinity score -8.26 kcal/mol with Histamine-H2 receptor and The ligand Beutilinc acid showed binding affinity score of -6.68 kcal/mol for (H+ /K+ -ATPase) receptor. From these studies, it is demonstrated that Ziziphus rugosa bark consists of potential leads for ulcer healing activity as revealed by in silico studies.

Commentary: Best practices for performing olfactory behavioral assays on aquatic animals: A guide for comparative physiologists

As more physiologists start to incorporate animal behavior into their experiments, especially in the olfactory behavior research field, some considerations are often overlooked, partly due to the inherited way that physiological experiments are traditionally designed and performed. Here we highlight some of these subtle but important considerations and make a case for why these might affect the results collected from behavioral assays. Our aim is to provide useful suggestions for increased standardization of methods so they can be more easily replicated among different experiments and laboratories. We have focused on areas that are less likely to be mentioned in the materials and methods section of a manuscript such as starvation, preliminary experiments, appropriate sample sizes and considerations when choosing an odorant for an assay. Additionally, we are strongly cautioning against the use of alarm cue to generate behavioral responses due to its highly unstable chemical properties/potency. Instead, we suggest using pure chemicals (made up of one known molecule) such as amino acids, bile acids, or polyamines that are commercially available and easier to make up in known concentrations. Lastly, we strongly suggest using environmentally relevant concentrations of these odorants. We believe these guidelines will help standardize these assays and improve replication of experiments within and between laboratories.

The evolutionary arch of bioenergetics from prebiotic mechanisms to the emergence of a cellular respiratory chain

This article proposes an evolutionary trajectory for the development of biological energy producing systems. Six main stages of energy producing system evolution are described, from early evolutionary pyrite-pulled mechanism through the Last Universal Common Ancestor (LUCA) to contemporary systems. We define the Last Pure Chemical Entity (LPCE) as the last completely non-enzymatic entity. LPCE could have had some life-like properties, but lacked genetic information carriers, thus showed greater instability and environmental dependence than LUCA. A double bubble model is proposed for compartmentalization and cellularization as a prerequisite to both highly efficient protein synthesis and transmembrane ion-gradient. The article finds that although LUCA predominantly functioned anaerobically, it was a non-exclusive anaerobe, and sulfur dominated metabolism preceded phosphate dominated one.

(Invited) Green Ammonia Production from Electrochemically Upcycling Waste Nitrogen in an Membrane-Free Alkaline Electrolyzer

NH3 is an essential nutrient for life, but its production through anthropogenic N2-fixing process has caused alarming damages to ecosystems and human health. Excessive NO3 - leakage into water bodies due to overfertilization has led to the formation of "dead zones" in coastal areas. Denitrification generates N2O, which is 300 times more potent than CO2. Restoring the balance between the generation and elimination of Nr is an urgent task for humanity. Efforts to address the negative impact of human-generated Nr have focused on converting it to harmless N2 or improving its utilization in the nitrogen cycle. One promising method is electrochemical conversion, which can eliminate Nr without additional oxidants/reductants. However, achieving selective NO3RR toward N2 is challenging. An alternative approach is to convert other forms of Nr to NH3 in an electrochemical reactor, which could reduce the environmental impact of Nr and decrease the NH3 demand from the Haber-Bosch process, while also reducing the use of fossil-derived H2.In this work, we report our work on the development of a membrane-free alkaline electrolyzer (MFAEL), which transforms Nr into NH3 as the sole N-containing product. With the inexpensive and robust MFAEL system, we achieved an ampere-level partial current density towards NH3 production. By properly choosing the conditions of NH3 collection from MFAEL, continuous production of pure NH3-based chemicals can be realized without the need for additional separation procedures. Techno-economic analysis (TEA) suggests the potential economic feasibility of the waste-to-NH3 process by coupling electrodialysis (ED) for Nr concentration and the MFAEL process for Nr conversion, offering an all-sustainable route for upcycling waste N into the highest-demanded N-based chemical product. Our recent efforts on green-ammonia capture CO2 and reduction to valuable chemicals will also be briefly presented.

Luminescence performance and antioxidant properties of selenium carbon dots prepared from selenium-hyperaccumulating plants.

Heteroatom doping has become an important method to enhance the performance of traditional carbon dots in modern times. Selenium (Se) is a nonmetallic trace element with excellent redox properties and is therefore essential for health. Previous studies have mainly used pure chemicals as selenium sources to prepare selenium-doped carbon dots (Se-CDs), but the precursor pure chemicals have the disadvantages of being expensive, difficult to obtain, toxic, and having low fluorescence yields of the synthesised Se-CDs. Fortunately, our team achieved successful synthesis of selenium carbon dots, exhibiting excellent luminescence and biocompatibility through a one-step hydrothermal method using selenium-enriched natural plant Cardamine, as an alternative to selenium chemicals. This approach aims to address the limitations and high costs associated with Se-CDs precursors. Electron spin resonance spectroscopy (ESR) and cellular antioxidant tests have confirmed the protective ability of Se-CDs against oxidative damage induced by excessive reactive oxygen species (ROS). A new concept and method for synthesizing selenium carbon dots on the basis of biomass, a rationale for the antioxidant effects on human health, and a wide range of development and application possibilities were offered in this work.

Mechanistic insights into rumen function promotion through yeast culture (Saccharomyces cerevisiae) metabolites using in vitro and in vivo models.

Yeast culture (YC) enhances ruminant performance, but its functional mechanism remains unclear because of the complex composition of YC and the uncertain substances affecting rumen fermentation. The objective of this study was to determine the composition of effective metabolites in YC by exploring its effects on rumen fermentation in vitro, growth and slaughter performance, serum index, rumen fermentation parameters, rumen microorganisms, and metabolites in lambs. In Trial 1, various YCs were successfully produced, providing raw materials for identifying effective metabolites. The experiment was divided into 5 treatment groups with 5 replicates in each group: the control group (basal diet without additives) and YC groups were supplemented with 0.625‰ of four different yeast cultures, respectively (groups A, B, C, and D). Rumen fermentation parameters were determined at 3, 6, 12, and 24 h in vitro. A univariate regression model multiple factor associative effects index (MFAEI; y) was established to correlate the most influential factors on in vitro rumen fermentation with YC metabolites (x). This identified the metabolites promoting rumen fermentation and optimal YC substance levels. In Trial 2, metabolites in YC not positively correlated with MFAEI were excluded, and effective substances were combined with pure chemicals (M group). This experiment validated the effectiveness of YC metabolites in lamb production based on their impact on growth, slaughter performance, serum indices, rumen parameters, microorganisms, and metabolites. Thirty cross-generation rams (Small tail Han-yang ♀ × Australian white sheep ♂) with good body condition and similar body weight were divided into three treatment groups with 10 replicates in each group: control group, YC group, pure chemicals combination group (M group). Growth performance and serum index were measured on days 30 and 60, and slaughter performance, rumen fermentation parameters, microorganisms, and metabolites were measured on day 60. The M group significantly increased the dressing percentage, and significantly decreased the GR values of lambs (p < 0.05). The concentration of growth hormone (GH), Cortisol, insulin (INS), and rumen VFA in the M group significantly increased (p < 0.05). These experiments confirmed that YC or its screened effective metabolites positively impact lamb slaughter performance, rumen fermentation, and microbial metabolism.

Layered double hydroxides for simultaneous and long-term immobilization of metal(loid)s in soil under simulated aging

Soil contamination by toxic metals and metalloids poses a grave threat to food security and human well-being. Immobilization serves as an effective method for the remediation of soils contaminated by metal(loid)s. Nevertheless, the ability of soil amendments for simultaneous immobilization of cations and oxyanions, and the long-term effectiveness of immobilization need substantial improvements. In this study, we used a series of layered double hydroxides (LDHs), including Mg-Al LDH and Ca-Al LDH fabricated from pure chemicals, and one waste-derived LDH synthesized using granulated ground blast furnace slag (GGBS), for the immobilization of Cu, Zn, As, and Sb in a historically contaminated soil obscured from a mining-affected region. The LDHs were first subjected to iron (Fe) modification to enhance their short-term immobilization performances toward metal(loid)s. Furthermore, the long-term effectiveness of Fe-modified LDHs was examined via two sets of experiments, including column experiments simulating 2-year water leaching, and accelerated aging experiments simulating 100-year proton attack. It was observed that Fe-modified LDHs, either made from pure chemicals or GGBS, demonstrated promising long-term immobilization performances toward metal(loid)s. Results from this study are encouraging for the future use of LDHs for simultaneous and long-term immobilization of metal(loid)s in soil.

A Comparative Study on the Synthesis of Type &lt;i&gt;NaX &lt;/i&gt;Zeolite Prepared from Kaolin for Builder Application in Detergent Production

Zeolites being used as builders in detergents are synthesized from expensive chemicals with a cumbersome production process. In this study, zeolite was synthesized from cheaper and readily available kaolin for possible use in detergent production. Kaolin from two sources namely Ajebo, Ogun State and Darazo, Bauchi State, Nigeria was used as starting materials while wet beneficiation followed by acid leaching was used to purify the kaolin and hydrothermal process was used to synthesize the zeolite. The chemical analysis confirms the presence of silica and alumina which are the precursors materials for zeolite synthesis. An increase in the amounts of the desired silica and alumina for both kaolin accompanied by a reduction in the amounts of the undesired oxides present in the kaolin as impurities are clear indications that the acid leaching was successful. The zeolites synthesized from both kaolin shows better water adsorption capacity and ion exchange capacity compared to those reported for zeolite synthesized from pure chemicals, this ability makes zeolite more suitable for the production of detergent. These results are indications that zeolites synthesized from kaolin can serve as a possible replacement for the more expensive zeolite synthesized from chemicals used as builders in detergent production.

InChI isotopologue and isotopomer specifications

This work presents a proposed extension to the International Union of Pure and Applied Chemistry (IUPAC) International Chemical Identifier (InChI) standard that allows the representation of isotopically-resolved chemical entities at varying levels of ambiguity in isotope location. This extension includes an improved interpretation of the current isotopic layer within the InChI standard and a new isotopologue layer specification for representing chemical intensities with ambiguous isotope localization. Both improvements support the unique isotopically-resolved chemical identification of features detected and measured in analytical instrumentation, specifically nuclear magnetic resonance and mass spectrometry.Scientific contributionThis new extension to the InChI standard would enable improved annotation of analytical datasets characterizing chemical entities, supporting the FAIR (Findable, Accessible, Interoperable, and Reusable) guiding principles of data stewardship for chemical datasets, ultimately promoting Open Science in chemistry.

Ecologically Based Management of Pineapple Mealybug Wilt: Controlling Dysmicoccus brevipes Mealybug Populations with Salicylic Acid Analogs and Plant Extracts

Mealybug wilt of pineapple (MWP) is a destructive disease worldwide caused by a parasitic complex that includes Pineapple Mealybug Wilt-associated Viruses (PMWaVs) and mealybugs (Dysmicoccus brevipes), which concurrently act as vectors for these viruses. Reducing the mealybug population is key to managing MWP, which is achieved in intensive production systems through the use of insecticides. SA (salicylic acid), ASM (acibenzolar-S-methyl), BABA (β-aminobutyric acid), and MeSA (methyl salicylate) are key components of systemic acquired resistance (SAR), the defense mechanism of plants against biotrophic agents such as mealybugs. In this study, these compounds were applied either as pure chemicals and/or as a major constituent of plant extracts. Both the Hawaiian hybrid MD-2 and Queen Victoria tissue culture plants, as well as suckers used for vegetative propagation, were treated with these compounds by direct application on the soil of pineapple pots. Subsequently, five mealybugs were released on each plant or each daughter plant in case of a transgenerational experiment; then, after 45 days, the number of mealybugs was counted. Exogenous SA, ASM, and MeSA reduced the population of mealybugs by a minimum of 50% and up to 80%. These SAR-inducing treatments could be an interesting alternative for controlling mealybugs and are already used in other pathosystems. The SAR mechanisms behind this effect are yet to be confirmed by molecular and enzymatic markers. ASM and MeSA are promising treatments for pineapples using tissue culture plants or traditional shoots.

Audible sensing of low-ppm concentration gases

Reliable and consistent measurement of various gas molecules at low parts per million (low-ppm) concentration is an essential intermediary step towards low-cost versatile gas analysers. Here we demonstrate physical measurements of various low-ppm molecules by means of an acoustic standing wave-based resonating device with a speaker and a microelectromechanical systems (MEMS) microphone, using either the sound pressure level (SPL) at a fixed frequency, or alternatively, tracking the resonance frequency as gas molecules enter the acoustic device. Low-ppm gas molecules are measurable at frequencies near standing wave resonances, as slight shifts in the speed of sound result in a shift of the acoustic frequency response function. Since a chemical receptor layer on the sensing component is not required for the measurements, absolute physical quantities of the molecules are measurable, which coincide well theoretically with expected values for pure chemicals. Various conditions are tested using different low-ppm molecules to demonstrate the limit of detection (LOD), using a low-cost and portable acoustic setup. An LOD is determined to be in the order of several ppm for most molecules. Gas analysers based on a physical approach present new opportunities for mobile gas sensing in practical applications.

Defensive alteration of root exudate composition by grafting Prunus sp. onto resistant rootstock contributes to reducing crown gall disease.

Grafting is a traditional and significant strategy to suppress soil-borne diseases, such as the crown gall disease caused by tumorigenic Agrobacterium and Rhizobium. Root exudates and the rhizosphere microbiome play critical roles in controlling crown gall disease, but their roles in suppressing crown gall disease in grafted plants remain unclear. Here, disease-susceptible cherry rootstock 'Gisela 6' and disease-resistant cherry rootstock 'Haiying 1' were grafted onto each other or self-grafted. The effect of their root exudates on the soil microbiome composition and the abundance of pathogenic Agrobacterium were studied. Grafting onto the disease-resistant rootstock helped to reduce the abundance of pathogenic Agrobacterium, accompanied by altering root exudation, enriching potential beneficial bacteria, and changing soil function. Then, the composition of the root exudates from grafted plants was analyzed and the potential compounds responsible for decreasing pathogenic Agrobacterium abundance were identified. Based on quantitative measurement of the concentrations of the compounds and testing the impacts of supplied pure chemicals on abundance and chemotaxis of pathogenic Agrobacterium and potential beneficial bacteria, the decreased valine in root exudates of the plant grafted onto resistant rootstock was found to contribute to decreasing Agrobacterium abundance, enriching some potential beneficial bacteria and suppressing crown gall disease. This study provides insights into the mechanism whereby grafted plants suppress soil-borne disease.

Continuously Producing Highly Concentrated and Pure Acetic Acid Aqueous Solution via Direct Electroreduction of CO2.

It is crucial to achieve continuous production of highly concentrated and pure C2 chemicals through the electrochemical CO2 reduction reaction (eCO2RR) for artificial carbon cycling, yet it has remained unattainable until now. Despite one-pot tandem catalysis (dividing the eCO2RR to C2 into two catalytical reactions of CO2 to CO and CO to C2) offering the potential for significantly enhancing reaction efficiency, its mechanism remains unclear and its performance is unsatisfactory. Herein, we selected different CO2-to-CO catalysts and CO-to-acetate catalysts to construct several tandem catalytic systems for the eCO2RR to acetic acid. Among them, a tandem catalytic system comprising a covalent organic framework (PcNi-DMTP) and a metal-organic framework (MAF-2) as CO2-to-CO and CO-to-acetate catalysts, respectively, exhibited a faradaic efficiency of 51.2% with a current density of 410 mA cm-2 and an ultrahigh acetate yield rate of 2.72 mmol m-2 s-1 under neutral conditions. After electrolysis for 200 h, 1 cm-2 working electrode can continuously produce 20 mM acetic acid aqueous solution with a relative purity of 95+%. Comprehensive studies revealed that the performance of tandem catalysts is influenced not only by the CO supply-demand relationship and electron competition between the two catalytic processes in the one-pot tandem system but also by the performance of the CO-to-C2 catalyst under diluted CO conditions.

Green3: A green extraction of green additives for green plastics

PLA/PBAT bioplastic is a commercial biodegradable plastic employed for packaging and several food and agriculture applications. In this regard, properties such as the antioxidant ability to extend food shelf life and light resistance, are of great interest in the production of packaging and mulching films, respectively. These features are obtained by developing blends with pure chemicals and/or natural products as additives. In the present work blend formulations of PLA/PBAT with a walnut shell extract rich in antioxidants were developed and evaluated for their properties in comparison with classic PLA/PBAT. Specifically, natural additives, and most importantly the production process were purposely selected to i) be green and cost-effective; ii) confer antioxidant properties; and iii) improve material performance.To this aim, a walnut shell extract (EWS) with high antioxidant activity was obtained thanks to a novel green and cost-effective microwave-assisted extraction (MAE) procedure. A response surface methodology was utilized to explore how the total phenolic content (TPC) and antioxidant activity are influenced by varying aqueous ethanol concentration, extraction time, and microwave power. The highest predicted TPC and antioxidant activity were achieved when employing the ideal conditions for Microwave-Assisted Extraction (MAE): using a mixture of 30 % ethanol in water, an irradiation time of 120 s, and a microwave power of 670 W. The optimized EWS was characterized by HPLC-MS determining qualitative and quantitative data with the identification of flavonoids, fatty acids, and anacardic acids among the main components, responsible for antioxidant activity. The resulting EWS powder was melt-mixed at 140C° and 20 RPM with the bio-based PLA/PBAT bioplastic at two different concentrations (0.5 and 1.5 w/w) by forming film specimens. All EWS-based bioplastic films showed increased antioxidant features determined by the DPPH bleaching test, TEAC, and ORAC assays. The films keep the antioxidant capacity even after 7 days of UV-accelerated aging. Remarkably, adding 1.5 % EWS boosted the bioplastic UV light resistance, reducing the abatement of molecular masses by more than 60 % without affecting mechanical properties.

Mitigating heavy metal volatilization during thermal treatment of MSWI fly ash by using iron(III) sulfate as a chlorine depleting agent

In the thermal treatment of municipal solid waste incineration fly ash (FA), the presence of chlorides leads to the pronounced volatilization of heavy metals at high temperature, making heavy metals stabilization challenging. Conventional washing processes struggle to remove chlorides completely, and even minor residual chlorides can lead to significant heavy metal volatilization. This study innovatively applied iron(III) sulfate as a chlorine depleting agent, which can form FeCl3 (boiling point 316 °C) and volatilize to remove the residual chlorides at below 500 °C, thus preventing the chlorination and volatilization of heavy metals at 600–1000 °C. Using water-washed FA to produce lightweight aggregate (LWA) preparation, after adding iron(III) sulfate, the volatilization rates of Pb and Cd at 1140 °C decreased to 5.4% and 9.3%, respectively, a reduction of 82.8% and 84.1% compared to before its addition. The LWA met standard requirements in both performance and heavy metal leaching toxicity. The mechanism was further studied through thermodynamic equilibrium calculations and heating experiments of pure chemicals. This study presents novel approaches and insights for suppressing the volatilization of heavy metals in FA at high temperature, thereby promoting the advancement of thermal treatment techniques and the safe, resourceful disposal of FA.

Exploration of the Biocontrol Activity of Bacillus atrophaeus Strain HF1 against Pear Valsa Canker Caused by Valsa pyri.

Valsa pyri-induced pear Valsa canker is among the most prevalent diseases to impact pear quality and yields. Biocontrol strategies to control plant disease represent an attractive alternative to the application of fungicides. In this study, the potential utility of Bacillus atrophaeus strain HF1 was assessed as a biocontrol agent against pear Valsa canker. Strain HF1 suppressed V. pyri mycelium growth by 61.20% and induced the development of malformed hyphae. Both culture filtrate and volatile organic compounds (VOCs) derived from strain HF1 were able to antagonize V. pyri growth. Treatment with strain HF1-derived culture filtrate or VOCs also induced the destruction of hyphal cell membranes. Headspace mixtures prepared from strain HF1 were analyzed, leading to the identification of 27 potential VOCs. Of the thirteen pure chemicals tested, iberverin, hexanoic acid, and 2-methylvaleraldehyde exhibited the strongest antifungal effects on V. pyri, with respective EC50 values of 0.30, 6.65, and 74.07 μL L-1. Fumigation treatment of pear twigs with each of these three compounds was also sufficient to prevent the development of pear Valsa canker. As such, these results demonstrate that B. atrophaeus strain HF1 and the volatile compounds iberverin, hexanoic acid, and 2-methylvaleraldehyde exhibit promise as novel candidate biocontrol agents against pear Valsa canker.

Relevance of complement immunity with brain fog in patients with long COVID

IntroductionThis study aimed to elucidate the prevalence and clinical characteristics of patients with long COVID (coronavirus disease 2019), especially focusing on 50% hemolytic complement activity (CH50). MethodsThis retrospective observational study focused on patients who visited Okayama University Hospital (Japan) for the treatment of long COVID between February 2021 and March 2023. CH50 levels were measured using liposome immunometric assay (Autokit CH50 Assay, FUJIFILM Wako Pure Chemical Corporation, Japan); high CH50 was defined as ≥59 U/mL. Univariate analyses assessed differences in the clinical background, long COVID symptoms, inflammatory markers, and clinical scores of patients with normal and high CH50. Logistic regression model investigated the association between high CH50 levels and these factors. ResultsOf 659 patients who visited our hospital, 478 patients were included. Of these, 284 (59.4%) patients had high CH50 levels. Poor concentration was significantly more frequent in the high CH50 group (7.2% vs. 13.7%), whereas no differences were observed in other subjective symptoms (fatigue, headache, insomnia, dyspnea, tiredness, and brain fog). Multivariate analysis was performed on factors that could be associated with poor concentration, suggesting a significant relationship to high CH50 levels (adjusted odds ratio [aOR], 2.70; 95% confidence interval [CI], 1.33–5.49). Also, high CH50 was significantly associated with brain fog (aOR, 1.66; 95% CI, 1.04–2.66). ConclusionsHigh CH50 levels were frequently reported in individuals with long COVID, indicating a relationship with brain fog. Future in-depth research should examine the pathological role and causal link between complement immunity and the development of long COVID.