Oxidation Method Research Articles

Statistical Analysis of the Influence of Various Types of Graphite Precursors and Oxidation Methods on the Gas Sensor Properties of Reduced Graphene Oxide.

The fabrication process of reduced graphene oxide depends on many factors (e.g., graphite precursor, methods of oxidation, reduction, and exfoliation) which have a significant influence on the properties of this material. Therefore, their selection is not easy due to the large number of possible combinations of these factors. To overcome this problem, we proposed to use a multivariate analysis of variance method of finding associations between the qualitative type of independent variables and the quantitative type of dependent variable. Using ANOVA, we showed that the combination (interaction) of these variables is more important than the individual influence of the variables on the fabricated rGO. Knowing how the particular variables and their combinations affect the properties of rGO, it is easier to plan the fabrication process of this material. In this paper, we analyzed the number of oxide layers and designated the most promising oxides in terms of sensor gas application. Independently, we fabricated chemiresistor sensors and studied their response to NO2 in the analyzed atmosphere. We were able to combine the experimental results with statistical analysis indicating which oxidation methods and which graphite precursors will provide the best sensitivity.

Design, Synthesis, and Anti-Prostate Cancer Potential of 2-(4-Nitrobenzyl) Malonates In Vitro and DAL Acute Oral Toxicity Assessment In Vivo.

New 4-nitrobenzyl derivatives were designed and synthesised by nucleophilic substitution reactions of 4-nitrobenzyl bromide with malonic acid and its derivatives. The synthesised molecules were characterised using mass analysis and spectroscopic techniques and tested for their antioxidant properties using various methods, such as nitric oxide, DPPH, and hydrogen peroxide radical scavenging methods. The anti-inflammatory activities of the molecules were assessed using RBC membrane stabilisation and albumin denaturation methods. We evaluated the compounds' potential anti-prostate cancer activity using the DU145 cell line. The MTT assay determined the cell viability, indicating good anti-proliferative activity. The molecule 3 c exhibited the highest potency, with a CTC50 of 11.83 μg/mL. Molecular dynamics simulations were performed to study the stability of the ligand within the protein after docking and the resulting protein-ligand complex. The in vivo analysis of molecule 3 c in the DAL xenograft model demonstrated promising results. The increase in life span, reduction in tumor volume, and comparable effects to standard drugs are encouraging features that suggest that molecule 3 c may possess significant potential as an anti-cancer agent. The research also implies that these molecules might be potential lead compounds for developing new prostate cancer drugs.

Advances in Nickel Hydroxide: Structures and Modern Applications (review)

This review article provides an overview of research conducted over the past few decades on nickel hydroxide, a crucial material in both physics and chemistry with notable engineering applications, particularly in batteries. It begins by outlining the structures of the two known polymorphs, α-Ni(OH)2 and β-Ni(OH)2. The article also explores various types of disorder commonly found in nickel hydroxide, such as hydration, stacking faults, mechanical stresses, and the incorporation of ionic impurities. Related materials, including intercalated α-derivatives and basic nickel salts, are also discussed. The review goes on to summarize several methods for synthesizing nickel hydroxide, such as chemical and electrochemical precipitation, sol–gel synthesis, chemical aging, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwave-assisted synthesis, and sonochemical methods. Finally, the known physical properties of nickel hydroxide—magnetic, vibrational, optical, electrical, and mechanical—are examined. The concluding section offers a summary of the potentially valuable properties of these materials and techniques for identifying and characterizing unknown nickel hydroxide-based samples.

Дослідження впливу природної та штучної пасивації на швидкість корозії магнієвого сплаву для хірургічних імплантатів

Magnesium-based alloys are widely used materials for surgical implants. Considerable efforts of researchers are applied to the development of new magnesium alloys and methods of their surface treatment in order to protect against biocorrosion or to regulate its speed. The idea of the work is to determine the potential of known magnesium alloys as materials for the production of implants. Industrial magnesium based alloys were analyzed from the point of view of suitability for use for surgical biodissolvable implants. It is shown that the ML10 alloy is the most suitable as it does not contain toxic components, namely aluminum, nickel and cadmium. Samples for corrosion tests were made from a billet of ML10 alloy after processing by plastic deformation by pressing through a calibrated die at a temperature of 375 ± 20 °С. Together with the ML10 alloy, comparative studies of the ML5 alloy were conducted. Corrosion tests of ML5 and ML10 alloys without a coating, as well as of the ML10 alloy with a coating applied by the micro-arc oxidation (MAO) method for 30 seconds, were carried out using the volumetric method. The samples were kept in a 3% NaCl solution at a temperature of 38 ± 2 °C. The corrosion rate of the ML5 alloy was at a constant level during the experiment. No significant ability of the ML5 alloy to self-passivate was found. The ML10 alloy turned out to be capable of significant self-passivation under the influence of a corrosive environment. During the experiment, the corrosion rate of the ML10 alloy sample decreased approximately ten times. It was also established that the corrosion rate of ML10 alloy samples with MAO coating was approximately three times lower than that of samples of the same alloy without coating. Preliminary information was obtained on the reduction of the corrosion rate of the ML10 alloy after plastic deformation. Further research can be aimed at confirming this phenomenon, determining its causes, as well as establishing quantitative indicators of the influence of the degree of plastic deformation on the corrosion rate of the ML10 alloy. Keywords: surgical implants, magnesium alloys, corrosion, self-passivation, coating.

Evaluation of the Polypyrrole Coupling Mode for High-Performance Dual-Ion Batteries.

Due to the advantages of large interstitial sites, antisolubility, and reversible insertion and extraction of anions, polypyrrole (PPy) has become an excellent P-type electrode material for dual-ion batteries. Unfortunately, PPy electrodes inevitably suffer from low specific capacity and poor cycle stability because of structural disintegration during repeated cycling as well as poor doping ability brought on by aggregation or cross-linking within the PPy chain. In this work, PPy with different proportions of coupling mode (α-α, α-β, or β-β coupling) was derived from different preparation methods. Among them, PPy derived from the interfacial frozen polymerization method (I-PPy) is dominated by the α-α coupling mode and possesses the best anion doping ability and the highest specific capacity of 119 mAh g-1 at 100 mA g-1 compared with PPy derived from electrochemical deposition (E-PPy) and chemical oxidation method (C-PPy) (both less than 40 mAh g-1). This work verifies that increasing the proportion of the α-α coupling mode in the PPy electrode is a useful strategy to enhance the anion doping ability and capacity of dual-ion batteries.

Engineering ceria oxide with nickel doping and rich oxygen vacancies for enhanced electrocatalytic degradation of aromatic organics

Aromatic dyes are widely applicable in the textile, leather, and ink industries yet receive serious contamination issues to water bodies, soil, and even air. Herein, we develop an efficient electrocatalytic oxidation method for degrading aromatic dyes via developing supportive CeO2-based electrode materials decorating with highly dispersive Ni and rich oxygen vacancies. The decorating Ni species are in situ converted from a composite of CeO2 nanocrystals and formamide-derived polyaminoimidazole (PAI)-coordinated Ni to ensure the high dispersion of Ni species. The decomposition of PAI ligands also helps to create the localized reductive atmosphere for the generation of rich surface oxygen vacancies, which further benefits the enhancement of electronic conductivity and charge transport ability. The effects of Ni doping concentrations, Rhodamine B (RhB, as a simulating aromatic dye) concentrations, pH of RhB solution, types and concentrations of electrolytes, and working current densities on the degradation performance are comprehensively investigated. Electrocatalytic measurements reveal that the CeO2 catalyst with optimal Ni concentration and fine single-crystal sizes of 5.5 ± 0.03 nm (termed as Ni0.025-CeO2-x) exhibits very promising degradation efficiency (96.9 %) and structural durability (repeated use for 5 cycles with limited activity decrease).

Self-Polymerized Tough and High-Entanglement Zwitterionic Functional Hydrogels.

Zwitterionic hydrogels exhibit great potential in biomedical applications due to their antifouling properties and biocompatibility. However, the single-network structure of pure zwitterionic hydrogels leads to a low toughness and strength, limiting their application in biomedical fields. In this work, a high entanglement sulfobetaine methacrylate-dopamine hydrogel (SBMA-DA-PE) with low cross-linker content and high monomer concentration is prepared by using a dopamine oxidative radical polymerization method. Compared to a regular zwitterionic hydrogel, the SBMA-DA-PE hydrogel exhibits a 5-fold increase in tensile fracture stress and a 10-fold increase in compressive fracture stress. The SBMA-DA-PE hydrogel possesses excellent mechanical properties (the maximum compressive stress ≥4.85MPa, the maximum compressive strain ≥90%). Besides, the non-covalent interactions between catechol or ortho-quinones within the SBMA-DA-PE hydrogel, combined with strong intermolecular electrostatic interactions, endow the SBMA-DA-PE hydrogel with great self-healing capabilities and fatigue resistance. The SBMA-DA-PE hydrogel demonstrates low swellability and possesses good antifouling properties. Furthermore, the good printability and conductivity of the tough SBMA-DA-PE hydrogel endows it with new possibilities for developing biological 3D scaffolds and electronic devices. Overall, this work provides new insights into the preparation of zwitterionic hydrogels with high mechanical strength and multi-functionality for biomedical applications.

Decontamination of Biological Agents in Wastewater through Synergetic Oxidative Methods as an Effective Approach for Safeguarding Public Health and Aquatic Ecosystems

We employed a highly concentrated model of wastewater to conduct our research, accurately mimicking the composition of wastewater generated by milk processing enterprises. Wastewater contained milk protein, carbohydrates, and whey sugars. Domestic wastewater, which served as a source of indicator fecal microorganisms, was added to them. The water purification and disinfection scheme involved treating a model wastewater using the biosorption method with an immobilized biocenosis in a laboratory installation, followed by further purification and disinfection in a decontamination tank. In comparison, we assessed the degree of microorganism elimination using distinct methods such as ozonation, hydrogen peroxide treatment, and combination of О3/Н2О2. It has been demonstrated that model wastewater, purified and disinfected using the AOPs method, also contains dissolved oxygen, which is non-toxic to aquatic microbiota.

Experimental Antioxidant Activities of Synthetic 3,4-Dihydropyrimidine Derivatives.

The synthesized of five new pyrimidine derivatives was prepared from the condensation in one pot reaction of ethyl acetoacetate, substituted aromatic aldehydes, urea, and FeCL3.6H2O, with 5 to 10 drops of hydrochloride acid as catalyst in reflexing ethanol. The yield of the product was found to be in the range of 55 to 90%. The antioxidant efficiency of synthesized compounds was estimated by using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method, hydroxyl method, nitric oxide method, and superoxide radical scavenging assay method. The compounds 6a, 6e, and 6c demonstrated considerable radical scavenging activity, resulting in the presence of electron-donating substituent on replaced aldehydes. The confirmation compounds by spectral data by proton and 13C-nuclear magnetic resonance, infrared spectra, and MS spectra.

An All-Solid-State Ti/RuOx pH Electrode Prepared Based on the Thermal Oxidation Method.

The development of all-solid-state precise pH electrodes holds significant importance in various fields, particularly in marine scientific research. To achieve this goal, we proposed a novel fabrication technique for an all-solid-state ruthenium oxide (Ti/RuOx) pH electrode. We thin-coated the RuCl3 precursor solution on a titanium wire substrate using a heat gun repeatedly and then calcined it in a mixture of Li2CO3 and Na2O2 at 400 °C to obtain a ruthenium oxide (RuOx) film. This RuOx film was subjected to acid treatment with dilute nitric acid, and a polytetrafluoroethylene heat shrink tube was wrapped around the non-RuOx film area. Finally, the RuOx film was fully immersed in a pH 4.00 buffer solution, finalizing the electrode preparation. The RuOx film exhibits a dense and regular conical morphology. The Ti/RuOx electrode demonstrates a good near-Nernstian response slope (e.g., -59.04 mV/pH at 25 °C), high linearity (e.g., R2 = 0.9999), rapid response (<1 s), low hysteresis (<3 mV), excellent reversibility, and good repeatability in the pH range of 2.00-10.00. After full hydration, the Ti/RuOx electrode shows a potential drift of 8.5 mV and a drift rate of approximately 0.27 mV/day over a period of 25 days, indicating good long-term stability. Furthermore, the Ti/RuOx electrode exhibits robust resistance against interference from various ions and low-concentration redox substances, ensuring a long storage life (at least 280 days), and high measurement accuracy (e.g., ± 0.02 pH units) for diverse water samples, including seawater, freshwater, and tap water. This study has evaluated the potential of the Ti/RuOx electrode as a reliable and accurate tool for pH measurements in marine scientific applications.

Prevalence of vitamin C deficiency and its association with stroke risk among U.S. adult population: A cross-sectional analysis spanning 15 years with over 13,000 participants

Background: Stroke presents a significant global health challenge. Despite its potential for cardiovascular protection, the role of vitamin C (VTMC) in stroke risk remains contentious. Aim: This study aimed to assess VTMC deficiency in stroke patients and its association with stroke risk. Methods: We analyzed data from 13,339 adults aged 20 and above in the National Health and Nutrition Examination Survey (NHANES) between 2003 and 2018, excluding those with missing serum VTMC and stroke status. We assessed the VTMC deficiency (&lt;11.4 µmol/L) and stroke incidence association using multivariate weighted logistic regression, adjusting for demographics, BMI, medical history, smoking, and dietary VTMC intake. Results: Stroke rates in the NHANES cycles 2003–2006 and 2017–2018 were 2.8% (95% CI [2.3–3.4]) and 3.3% (95% CI [2.7–4.2]), respectively. VTMC deficiency was more common in individuals with a history of stroke, with rates of 3.6% (95% CI [2.2–5.8]) and 5.3% (95% CI [3–9.1]) compared to 2.7% (95% CI [2.3–3.3]) and 3.2% (95% CI [2.5–4.1]) in the nonstroke population. Nevertheless, VTMC deficiency was distinctly prevalent across diverse demographic and health-related subgroups. Multivariate analyses invalidated any statistically significant association between VTMC deficiency and stroke risk across all employed analytical models within both time intervals. Conclusions: Our study does not support a link between VTMC deficiency and increased stroke risk in U.S. adults. Substantial uncertainties persist regarding the use of VTMC for stroke-related oxidative stress, dosage, and delivery methods, requiring further clinical trials. Healthcare providers should carefully consider its prevalence in specific subgroups.

Chemiresistive flexible gas sensor for NO2 sensing at room-temperature using in situ constructed Au@In2S3/In2O3 hybrid microflowers

The construction of a novel Au nanoparticles loaded In2S3/In2O3 hybrid microflowers composite was conducted through a well-designed hydrothermal and partial oxidation method and used for NO2 sensing at room-temperature (RT). The characterization data confirmed the hybrid structures and demonstrated that the ratio of adsorbed oxygen species on the surface increased after partial oxidation. The sensing performance of flexible gas sensors based on In2S3/In2O3, In2O3, AuxIn2S3/In2O3 (x = 0.5, 1 and 2 wt%) were tested and compared at RT. Heterostructure construction and Au NPs loading significantly improved the sensing properties at RT. Peculiarly, the response value of 1 wt% Au NPs loaded In2S3/In2O3 (Au1In2S3/In2O3) sensor for 100 ppm NO2 at RT was 20.7, which was 9.2 times higher than that of In2O3 sensor. Meanwhile, it also possessed excellent selectivity, fast response/recovery time (12/27 s), good repeatability, long-term and mechanical stability. The outstanding sensing performance for NO2 at RT mainly associated to the heterojunction between In2S3 and In2O3 and the catalytic effect of Au NPs. Finally, density functional theory (DFT) was used to calculate and analyze the gas adsorption and charger transfer, which related to the enhanced sensing performance.

Modulating Carbon Fiber Surfaces with Vinyltriethoxysilane Grafting to Enhance Interface Properties of Carbon Fiber/Norbornene-Polyimide Composites.

In this study, vinyltriethoxysilane (TEVS) was introduced onto the surface of carbon fiber using liquid-phase oxidation and impregnation methods to incorporate vinyl groups onto the carbon fiber, thereby enhancing the chemical bonding between the carbon fiber and norbornene-polyimide (PI-NA). Through a systematic study of the hydrolysis conditions and concentration of the TEVS solution, the optimal modification conditions were determined. These conditions were used to graft TEVS onto the surface of oxidized carbon fiber to prepare carbon-fiber-reinforced PI-NA composites (CF/PI-NA). The results show that when carbon fiber was treated with a 0.4 wt% TEVS solution, the interlaminar shear strength (ILSS) of the composites reached 65.12 MPa, and the interfacial shear strength (IFSS) reached 88.58 MPa, representing increases of 27.58% and 35.62%, respectively, compared to the CF/PI-NA composite materials prepared from untreated carbon fiber. It is worth noting that the modification method described in the study is simple and easy to implement, and it has the potential for large-scale continuous production applications.

Novel assessment of molten salt oxidation for cation exchange resin treatment: Effective neutralization of sulfurous gas with Li2CO3-Na2CO3-K2CO3 system

The conventional thermal treatment of cation exchange resin substantially releases sulfurous gases, causing significant equipment corrosion and air pollution. In contrast, the Li2CO3-Na2CO3-K2CO3 as an alkaline molten system effectively neutralizes sulfur gas and mitigates waste gas production inherent in thermal oxidation methods. In the molten salt oxidation process, the volume concentration of SO2 was reduced by 81.7 % compared to that in the traditional thermal oxidation process, and this method reduces the generation of hazardous gases such as CO, CH4, and C2H6. The integration of online gas mass spectrometry and phase stability diagrams for carbonate and sulfur interception products demonstrate excellent thermodynamic stability during the molten salt oxidation (MSO) process. Moreover, a more accurate assessment of the acid gas neutralization capacity of the molten salt system is provided, and the acid gas neutralization capacity of the Li2CO3-Na2CO3-K2CO3 carbonate system can reach 82.58 % at 800 °C. The predominant contributors to acid gas neutralization are Na2CO3 and K2CO3, as evidenced by waste salt composition and ternary phase diagrams. The stable presence of Li2CO3 throughout the MSO process contributes to the lowering of the melting point of the carbonate system to 393 °C.

Electroanalysis of bromate at riboflavin impregnated Ketjen black porous electrode via an autocatalytic cycle with finite length diffusion

The emergence of elevated concentrations of bromate, classified as a 2B type carcinogen, in drinking water following the treatment of water supplies with ozonation and other oxidation methods has underscored the importance of developing methods for reliable and rapid screening of drinking water. In this work, we report the use of electro activated riboflavin (RF) impregnated Ketjen black (KB) modified screen-printed electrode (elRF@KB-SPE) for the determination of bromate. The sensing surfaces were subjected to morphological and structural characterization using scanning electron microscopy and Raman spectroscopy. These analyses confirmed the successful modification of the electrode with an extended elRF@KB porous coating. Based on cyclic voltammetry (CV) and electrochemical impedance spectroscopy measurements, the response of elRF@KB-SPE towards bromate can be described through a dual mechanism involving i) an autocatalytic chemical/electrochemical process that predominantly occurs in the finite length pores of KB, and ii) an RF-mediated electrocatalytic process. Notably, the data demonstrated that the advanced electrocatalytic properties of the otherwise electrocatalytically inactive absorbed RF molecules are endowed after a simple electro activation process (three CV scans). Amperometric measurements at −0.05 V vs. Ag/AgCl revealed a linear relationship between the current response and the concentration of bromates over the concentration range 0.50−18.0 μM, achieving a limit of detection (3σ/slope) of 0.04 μM. The interference effect of various electroactive species was investigated demonstrating that elRF@KB-SPE is highly selective to bromate. The analytical utility of the method was evaluated in spiked tap water samples. Recoveries were 91.2 − 106.4 %.

An efficient Au/ZnO catalyst for the photocatalytic conversion of methane to formaldehyde

The photocatalytic oxidation of methane to value-added chemical products under mild conditions is crucial for resource utilization and environmental protection. However, inefficient generation of reactive oxygen species partially limits methane activation. To tackle this issue, we have developed highly dispersed Au-modified ZnO nanosheets through photo-deposition method for the photocatalytic oxidation of methane to formaldehyde. The optimized Au0.1/ZnO catalyst (0.1 wt% Au on ZnO) achieves a HCHO yield of 19.14 μmol h−1 with a selectivity of 87.94 %. Electron paramagnetic resonance, Raman, X-ray photoelectron spectroscopy and density functional theory show that Au enhances the concentration of oxygen vacancies (OVs) in ZnO. This enhancement is attributed to a strong interaction between Au and ZnO, which facilitates the transfer of electrons from the ZnO surface to Au. Under irradiation, Au and OVs function as hole and electron acceptors, respectively. This interaction promotes carrier separation, reduces charge recombination, enhances oxygen adsorption, and effectively generates reactive oxygen species, such as ·OH. Subsequently, CH4 is oxidized to ·CH3 by holes from Au. Concurrently, O2 is reduced by electron from OVs, following the pathways O2 → OOH→H2O2 → ·OH. The rapid oxidation of CH3OH by ·CH3 and ·OH results in the formation of HCHO.

Correlation between preparation techniques and frictional properties of cellulose nanocrystals as additives in water-based lubricants

To explore the tribological characteristics of cellulose nanocrystals derived through various preparation techniques when utilized as additives in water-based lubricants, two types of cellulose nanocrystals (S-CNC and C-CNC) were chosen. These were produced via sulfuric acid hydrolysis and oxidation methods. The morphology and structural features were assessed through techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), laser confocal Raman spectroscopy, elemental analysis, scanning electron microscopy (SEM), and laser particle size analysis. According to thermogravimetric analysis (TGA), the thermal stability of S-CNC is slightly superior to that of C-CNC. S-CNC exhibits liquid crystallinity when the concentration exceeds 0.5 %, whereas C-CNC does not display liquid crystallinity at any concentration tested. Further investigation was conducted on the frictional properties of the two types of CNCs using a UMT reciprocating friction tester. The results indicate that both types of CNC exhibit significant friction reduction properties at various additive concentrations, provided the addition does not exceed w=1 %. When below their respective liquid crystalline phase concentrations, the friction reduction performance of S-CNC is slightly inferior to that of C-CNC; however, when above the liquid crystalline phase concentration, the friction reduction performance of S-CNC surpasses that of C-CNC. The addition of w=0.5 % S-CNC leads to a relative reduction of 63.4 % in the friction coefficient compared to the base system. Analysis of the steel plate surface contact angle and post-wear surface suggests that the lubrication mechanism of CNC involves the adsorption of polar functional groups such as hydroxyl or carboxyl groups from the CNC structure onto the friction pair surface, forming a lubricating protective film to varying degrees. Additionally, the liquid crystalline structure of S-CNC facilitates the formation of an ordered lubricating film, further enhancing the frictional properties. These findings provide valuable insights into the application of nanocellulose crystals as lubricant additives.

Photothermal Catalytic Removal of 1,2-DCE with High HCl Selectivity over the Brønsted Acid-Enriched Sulfur-Doped MOFs.

Chlorinated volatile organic compounds come from a wide range of sources and are highly toxic, posing a serious threat to biological health and the environment. Herein, a high-efficiency and energy-saving photothermal synergistic catalytic oxidation method was developed for the removal of 1,2-dichloroethane (1,2-DCE). Compared to traditional thermocatalysis, the 1,2-DCE conversion over Ru-U6S in photothermal synergistic catalysis at 340 °C increased by approximately 44% not only reducing energy consumption but also avoiding the instability of MOF structure caused by high reaction temperature. The excellent photothermal catalytic oxidation activity was derived from the synergistic effect of photo- and thermocatalysis. Ru-U6S demonstrated excellent 1,2-DCE adsorption capacity and stronger light utilization and could produce more reactive oxygen species (•OH and •O2-) after light illumination, which participated in the oxidation reaction, promoting the release of the active site of the catalyst. The results of H2O-TPD and NH3-DRIFTS exhibited that the use of S-containing ligands in the synthesis process increased the hydroxyl groups and Brønsted acid sites, significantly improved the selectivity of CO2 and HCl in the oxidation process, and reduced the release of chlorine-containing byproducts. This work provides a high-efficiency and energy-saving strategy for removing chlorinated volatile organic compounds and increasing the selectivity of ideal products directly with MOFs directly.

Methane capture, utilization, and sequestration technology based on biological ectoine production using Methylotuvimicrobium alcaliphilum 20Z

Methanotroph-based CH4 conversion technology is a promising alternative to conventional CH4 utilization methods that rely on energy-intensive CO2 capture processes. In this study, we introduce a novel CH4 capture, utilization, and sequestration (MCUS) technology as a proof-of-concept for eco-friendly CH4 conversion that is applicable to various methanotroph strains. We validated this hypothesis by evaluating ectoine production in Methylotuvimicrobium alcaliphilum 20Z. Cultivation experiments were conducted using pure O2 pulse injection to facilitate the separation of the CO2 generated during CH4 oxidation by concentrating it. To verify the MCUS concept systematically, we performed a model-based process analysis. The operational strategies for the reactors were developed using experiment-based kinetics and reactor models, followed by the design of a rigorous process flow diagram. Economic and environmental impact analyses were conducted to compare MCUS with air-based cultures and existing oxidative CH4 conversion technologies. The key advantage of MCUS is its significantly lower CO2 emissions (0.71 kg-CO2 eq/kg-CH4) than oxidative CH4 utilization (>2.75 kg-CO2 eq/kg-CH4). Moreover, the net present value per CH4 molecule was estimated at 0.7 $/kg-CH4, substantially higher than existing oxidative conversion methods (0.03 $/kg-CH4). Additionally, compared with air-based cultivation, the MCUS process exhibits superior economic and environmental performances. We used methanotrophs for CH4 “capture” and “utilization,” effectively leveraging “sequestration” to convert emissions into pure CO2. The proposed MCUS technology holds promise for practical applications of methanotrophs in producing various high-value-added products, emphasizing eco-friendly approaches.

Chicken meal is not an appropriate reference protein for estimating protein quality of ingredients used in extruded diets intended for dogs.

The indicator amino acid oxidation (IAAO) method has been used to determine metabolic availability (MA) of amino acids in feedstuffs for pigs, humans, and preliminarily for cats. Peas are a commonly used protein source in grain-free extruded dog diets. However, peas have a poor sulfur amino acid (AA) ratio (methionine [Met]:cysteine) with Met being the first limiting AA. Furthermore, little is known about the MA of Met in peas fed to dogs. Therefore, our objective was to compare the MA of Met in peas to chicken meal (CM), as a gold-standard reference protein. The study was done as a replicated 5 × 5 complete Latin square design. Ten neutered male mixed-breed dogs (1.5 years old; 26.0 kg ± 2.4kg body weight; BW) fed to maintain ideal BW received all dietary treatments: BAS: lamb-based diet (deboned lamb and lamb meal) providing Met at 50% of its requirement (0.27g/100g dry matter [DM]), CHK: CM and lamb-based diet, and PEA: ground dried pea and lamb-based diet both providing Met at 68% of its requirement (0.35 and 0.37g/100g DM, respectively). Two other treatments were created by blending BAS with PEA (BAP) and the BAS with CHK (BAC) to create diets with Met at 59% of requirement (0.32 and 0.31g/100g DM, respectively). This resulted in three graded levels of Met for both CM and peas to allow for a slope-ratio assay approach to quantify MA with the BAS diet as the common first point. All other AAs were provided to meet at least 120% of the AAFCO recommendations for adult dogs. The BAS diet, with supplemental DL-Met, was fed for a 2-wk wash-in period. After 2 d of diet adaptation IAAO was performed. Dogs were fed 13 small meals where meal 6 contained a priming dose (9.4mg/kg BW) of L-[1-13C]-phenylalanine (Phe; 99%) as well as a constant dose (2.4mg/kg BW) in meals 6-13. Breath samples were collected and enrichment of 13CO2 was measured using isotope-ratio mass spectrometry to calculate the rate of Phe oxidation (F13CO2 umol/kg BW/h). Oxidation was analyzed via SAS using PROC GLIMMIX with dog and period as random effects, and diet, %Met, and their interaction as fixed effects. Unexpectedly, the slope of Phe oxidation, in response to increasing Met intake, from CM was 31% of that of peas, indicating a lower MA for Met in CM as compared to peas. This finding may be due to damage of AAs during rendering. At this time, CM in extruded diets is not an acceptable reference protein to determine MA of AAs in dogs, and the MA of Met from peas cannot be confidently assessed.