Reaction Period Research Articles

Temporal Optimization in the Synthesis of Multifunctional Nano Agents for Enhanced MRI Contrast, Hyperthermia Therapy, and ROS Generation.

Advanced methodologies, such as hyperthermia and modulation of reactive oxygen species (ROS), exhibit considerable promise in the therapeutic landscape of cancer. These strategies offer a targeted paradigm for combating malignant cells while mitigating damage to healthy tissue. Noteworthy among these approaches is the utilization of superparamagnetic iron oxide nanoparticles, which are renowned for their ability to enhance both hyperthermia and ROS generation specifically within tumor microenvironments. The objective of this investigation is to scrutinize the relationship between the reaction duration and the characteristics of carbon-doped silica core-shell iron oxide nanoparticles (CSIONPs). Specifically, we focus on CSIONP-12, CSIONP-24, and CSIONP-36, synthesized by using varying reaction periods. Through a comprehensive analysis, we primarily evaluate the impact of these formulations on T1 and T2 magnetic resonance imaging (MRI), aiming to elucidate their mechanisms and therapeutic potential in promoting hyperthermia and ROS-mediated cancer therapy. CSIONP-24 emerges as a compelling candidate due to its dual influence on magnetic hyperthermia and ROS generation, suggesting its promise in enhancing cancer treatment outcomes. Furthermore, the findings underscore the exceptional T1-T2 MRI capabilities of this technology, underscoring its versatility and efficacy in the nuanced realm of cancer theranostic.

Rapid sonochemical synthesis of highly active and stable 2-D inorganic-organic hybrid catalyst for solvent-free CO2 cycloaddition with epoxides

In order to find a better alternative of conventional hydrothermal method, a novel rapid sonochemical route has been developed for the synthesis of inorganic-organic hybrid metal phosphonate (i.e., Copper phenyl phosphonate (CuPPA)) at ambient conditions and examined as a catalyst in the transformation of carbon dioxide into cyclic carbonates in solvent-free condition. For the first time, the present study has explained the sonochemical synthesis of the 2-D nano-architecture of S-CuPPA within a short reaction period of 2 h at room temperature. However, the hydrothermal method requires high temperature of 443 K and reaction time of 48 h. Materials obtained from both methods have been compared using characterization techniques such as XRD, FT-IR, N2 sorption, FESEM, TEM, XPS, and TGA-DTA. Interestingly, S-CuPPA demonstrates crystallites of smaller size and higher surface area than HCuPPA. The S-CuPPA catalyst exhibited higher catalytic performance with conversion = 99 %, selectivity = 99 %, and yield = 99 % without using any solvent at optimized conditions such as catalyst = 30 mg, co-catalyst (TBAB) = 15 mg, pressure = 4 bar, temperature = 100 °C, and time = 24 h. The easy recoverability, stability, and ability to be recycled over five times with more than 93 % conversion demonstrate its ability to be a suitable industrial catalyst.

Resourceful exploitation of sedimentary clay: Designing a dual-chambered borosilicate glass reactor system for the efficient treatment of malachite green and phenol through SCRT adsorption and 5%Fe@SRCT catalysis via CWPO, with evaluation of seed germination and fish survival.

This study presents an innovative double-walled borosilicate glass reactor system for the efficient treatment of liquid and gaseous wastewater. This reactor system allows precise temperature control, continuous pH monitoring, and controlled dosing of reagents to optimize reaction conditions. Detailed characterization was carried out by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), BET (specific surface area) analysis, point of zero charge (PZC), and scanning electron microscopy (SEM) for the SCR, SCRT, and 5%Fe@SCRT materials. For Malachite Green adsorption, SRCT demonstrated a maximum adsorption capacity of 39.78 ±0.5mg/g using the Langmuir isotherm model and followed pseudo-second-order kinetics. Optimum conditions for adsorption were found to be: an initial concentration of 50 ppm, an adsorbent dosage of 1g/l, a pH of 8.5, and a temperature of 50°C. For the catalytic oxidation of phenol, 5%Fe@SRCT achieved a remarkable removal rate of 99.9±0.1% under optimum conditions (50 ppm phenol, 1g/l catalyst dosage, pH3.5, H2O2 concentration 8.7mM, and temperature 70°C). Intermediates identified during the reaction included hydroquinone, benzoquinone, catechol, and resorcinol, with degradation occurring over a 60-minute reaction period. The 5%Fe@SCRT material showed excellent reusability in the removal of phenol by catalytic oxidation, with no significant loss of efficiency over three cycles, while the SRCT underwent three cycles of regeneration for the adsorption of Malachite Green. Scavenger tests confirmed the involvement of hydroxyl radicals in the catalytic oxidation process. In addition, fish survival tests after catalytic oxidation of phenol by 5%Fe@SRCT showed no impact on fish, underlining the environmental safety of this process. In addition, germination tests after decolorization of MG by SRCT demonstrated a good effect with no negative impact, reinforcing the ecological value of this innovative technology. These results highlight the innovative use of SCRT and 5%Fe@SCRT as versatile materials for environmental remediation, exploiting their effective adsorption capacities and efficient catalytic oxidation performance within the proposed double-walled borosilicate glass reactor system. PRACTITIONER POINTS: The study demonstrates the effectiveness of an innovative reactor system employing SRCT adsorbent and Fe@SRCT catalyst for efficient removal of malachite green and phenol from wastewater. Environmental impact assessment, including seed germination and fish survival evaluation, validates the method's eco-friendly potential. Implementation of this approach could significantly contribute to sustainable water treatment practices.

Hybrid process combining ultrafiltration and electro-oxidation for COD and nonylphenol ethoxylate removal from industrial laundry wastewater

Laundry wastewater is a significant source of nonylphenol ethoxylate (NPEO) at wastewater treatment plants, where its breakdown forms persistent nonylphenol (NP). NP poses risks as an endocrine disruptor in wildlife and humans. This study investigates the degradation of NPEO and COD in industrial laundry wastewater (LWW) using a two-stage process combining ultrafiltration (UF) and electro-oxidation (EO). UF was used to remove suspended solids, while soluble COD (COD0 = 239 ± 6 mg.L−1) and NPEO (NPEO0 = 341 ± 8 μg.L−1) were oxidized by the EO process. Different operating parameters were studied such as current density, electrolysis time, type of cathode and supporting electrolyte concentration. Using an experimental design methodology, the optimal conditions for COD and NPEO3-17 degradation were recorded. This included achieving 97% degradation of NPEO3-17 and 61% degradation of COD, with a total operating cost of 3.65 USD·m−3. These optimal conditions were recorded at a current density of 15 mA cm−2 for a 120-min reaction period in the presence of 4 g·Na2SO4 L−1 using a graphite cathode. The EO process allowed for reaching the guidelines required for water reuse (NPEO <200 μg.L−1, COD <100 mg.L−1) in the initial laundry washing cycles. Furthermore, our results demonstrate that both NP and NPEO compounds, including higher and shorter ethoxylate chains (NPEO3-17), were effectively degraded during the EO process, with removal efficiencies between 94% and 98%. This confirms the EO process's capability to effectively degrade NP, the by-product of NPEO breakdown.

Synthesis of ZnV2O6 nanosheet photocatalysts for efficient photodegradation of Rhodamine B: Experimental and RSM modeling

A ZnV2O6 photocatalyst with nano-sheet morphology was synthesized using a facile solvothermal approach. To optimize the photo-decomposition of Rhodamine B (RhB), a new surface response methodology (RSM) based on the Central Composite Design (CCD) approach was employed. Several structural/microstructural and spectroscopic characterization techniques were utilized to describe the physical and chemical characteristics of ZnV2O6 (ZVO) nanosheet such as XRD, Raman, SEM-TEM, DRS, PL/TRF. The optimal conditions for RhB photo-decomposition were mathematically discussed as a function of four variables such as pollutant dose, pH values, photocatalyst-weight, and irradiation time, which were modeled by CCD-RSM employing a quadratic statistical model and an optimization approach (ANOVA analysis). RhB degradation efficiency of 97 % was achieved for the optimal conditions of pH = 8, photocatalyst mass = 95 mg, RhB concentration = 9 ppm, and irradiation time = 120. The registered reaction constant was 0.029 min−1. The removal efficiencies of TOC and COD when using the ZVO photo-catalyst for the RhB degradation were 83 % and 88 % respectively. The re-usability of ZnV2O6 samples has been assessed in 4 consecutive series revealing a high stability of the material after extended periods of photo-catalytic reaction. Furthermore, the active radical species involved in the breakdown of RhB were further confirmed through quenching tests in which hydroxyls and holes were found to be the major species contributing to the decomposition of RhB.

Enzymatic Synthesis of Prebiotic Carbohydrates from Lactose: Integration of Osmotic Membrane Distillation with Batch Reactor System

AbstractThis study aimed to enhance galactooligosaccharide (GOS) yield by maintaining high lactose concentration levels using osmotic membrane distillation (OMD) throughout the synthesis. The main problem influencing GOS yield during transgalactosylation is the decrease of lactose concentration over extended reaction periods. By integrating OMD with a continuous stirred batch reactor, water was progressively removed from the reaction medium. Compared to a standard batch reactor, the OMD-integrated system not only increased GOS yield by a maximum of 20.1% but also reduced the time needed for equivalent lactose conversion about 15–90 min. This integration particularly boosted the formation of longer-chain GOS. A consistent GOS yield of 67% was achieved, with up to 28% lactose conversion, surpassing the non-integrated reactor’s performance. The proposed reactor design shows promise for enhancing GOS production efficiency while concurrently concentrating the reaction medium in a single step.

A New Class of Multifunctional CoDyzFe2−zO4 Magnetic Nanomaterials: Influence of Structural, Morphological, Optical, Magnetic, Antibacterial, and Photocatalytic Traits

Here we focus on preparing recoverable Dy doped CoFe2O4 photocatalysts for the removal of the malachite green pollutant (MGP) in natural Sunlight. XRD results demonstrate development of the spinel symmetry with no impurities phases. The FESEM analysis revealed spherical grains with definite grain boundaries and agglomerated behavior. We found that our synthesized photocatalysts behaves as an excellent magnetic nanomaterial by observing the saturation magnetization of 77.79 emu g−1. Out of all photocatalysts, CoDy0.03Fe1.97O4 nanophotocatalyst exhibit the high zone of inhibition (ZOI) for Staphylococcus aureus and Escherichia coli. It makes the prepared nanomaterials highly suitable for the biological purposes. The effectiveness of photocatalytic degradation activity of prepared specimens is significantly impacted by the addition of dysprosium ions. During a 150 min of reaction period, CoDy0.03Fe1.97O4 has a higher degradation percentage around 95.36% as compared to CoFe2O4 (86.09%). The prepared doped and undoped CoFe2O4 nanomaterials displayed the least decline in the degradation percentage of MGP after four reuse cycles and this might be attributable to the weight loss during the recovery. Therefore, the nanomaterials suggested a reliable and durable photocatalyst for degradation process. Hence the prepared magnetically recoverable and multifunctional photocatalysts are reliable for the water remediation and biological usages.

Formation and health risk assessment of trihalomethanes in coastal wells impacted by seawater intrusion

The formation of trihalomethanes (THMs) in coastal wells impacted by seawater intrusion (SWI) is relatively understudied. Coastal wells, unlike typical groundwater sources, frequently exhibit elevated levels of chloride and bromide ions, potentially influencing the formation and speciation of THMs. The current study investigated the THM formation in coastal well water from a location affected by SWI. Samples were chlorinated with 2.5 mg L−1 and 5 mg L−1 chlorine doses to replicate field conditions. The THM concentration in the samples exceeded the maximum permissible limit for drinking water. The well with the highest chloride-to-bromide (Cl/Br) ratio (Cl/Br = 645) exhibited the highest total THM concentration (503.2 μg L−1). Samples with high bromide concentration had more brominated THMs over the 5-day reaction period. The bromine substitution factors for wells after 24 h with a chlorine dose of 2.5 mg L−1 were 1.89, 2.21, and 2.78, corresponding to bromide concentrations of 0.098, 0.109, and 1.275 mM, respectively. The average cancer risk associated with the well water was estimated to be 20.9 × 10−06 through dermal contact and 6.84 × 10−04 through inhalation. The study area had an estimated average cancer risk of 705 cases per million population. The study area's common diseases and cancer incidence data for the past four decades indicated a decreasing trend for waterborne diseases and a steep increase in cancers. While several factors may contribute to increasing cancer cases, our study highlights chlorinated coastal well water as an additional potential cancer risk agent.

Determination of parameters and kinetic evaluation for chromium (VI) removal using four resins

This research aimed to identify optimal studied variables for chromium (VI) removal using four resins (IRA 96, IRA 400, DOWEX 1x8, and LEWATIT). A 1,5-diphenylcarbazide method was used for the quantification of chromium (VI). A factorial design with triple replication at the center point was used to evaluate pH, resin dose (g/100 mL), and initial chromium (VI) concentration. The optimal values for the four resins were a pH of 3, a resin concentration of 0.15 g/100 mL of solution, and an initial concentration of 10 mg/L of chromium. Then, an ANOVA study was done to compare the resins results using a p-value &lt;0.05. The DOWEX resin presented the highest removal percentage (98.39%) for a reaction period of 45 minutes, with an exponential model that fits a pseudo-first-order kinetics with a coefficient of determination equal to 0.967.

Improvement in crystallization and digestion resistance of debranched amylopectin dextrins using sodium sulfate

In this study, sodium sulfate, a typical kosmotrope salt (100–500 mM), was used to resistant dextrin crystals prepared via enzymatic debranching, and its effects on the crystallization behavior and in vitro digestibility of the dextrin crystals were investigated. Waxy maize starch was enzymatically debranched (50 °C for 24 h) and simultaneously crystallized (50 °C for 2 d) in aqueous solutions containing sodium sulfate (0–500 mM). The yield of dextrin crystals was increased using a sodium sulfate solution (84% at 500 mM sodium sulfate). The dextrin crystals comprise an A-type arrangement of double helices with higher thermal stability than native starch. Based on the DSC, XRD, and in vitro digestibility test, the high thermal stability and crystallinity of the dextrin crystals provide high resistance to digestive enzymes. The addition of sodium sulfate during crystallization increased the crystallinity and thus increased the digestion resistance. According to the in vitro digestibility test, dextrin crystals prepared with 500 mM sodium sulfate contained a resistant fraction of 80.36% in the uncooked state. After cooking (boiling), over half of the dextrin crystals remain resistant to digestive enzymes. This study showed that sodium sulfate, a typical kosmotrope salt, could accelerate the crystallization process of the debranched waxy maize starch chain, increasing yield, thermal stability, crystallinity, and digestion resistance in a short reaction period.

Manganese-Doped Carbon Quantum Dots (CQDs) Prepared from Bovine Bone Powder and Their Application for the Fluorescent Determination of Chlorpyrifos

Employing a one-step hydrothermal method with bovine bone powder as the carbon source, Mn-doped fluorescent carbon quantum dots were synthesized. Experimental investigations were conducted on their morphology, structure, composition, and optical properties. The experiments were carried out at 280 °C, pH 7.0, and a reaction period of 12 h. A rapid residual method for organophosphorus pesticides (OPs) was developed based on the fluorescence quenching of quantum dots. A linear correlation between fluorescence quenching and OP concentration was established. Chlorpyrifos was chosen as the analyte for method evaluation. The findings showed that the fluorescence intensity of the Mn-BQDs decreased with the copper ion concentration. Furthermore, the influence of copper ions on the fluorescence quenching of carbon quantum dots varied with pH. At pH 7, copper ions exhibited optimal quenching with a detection limit of 5.8 × 10−4 mg/L. This method offers simplicity in operation and environmental friendliness, rendering it well-suited for the swift on-site screening of OPs.

Tracking Global Changes of Human Mobility Behavior and Resilience during the COVID-19 Pandemic

The COVID-19 pandemic has caused significant challenges to human mobility behavior worldwide. Our study examines the changes of human mobility behavior across 130 countries and regions during two periods: February 15th to August 15th, 2020 (the reaction period) and January 1st to June 30th, 2021 (the adaptation period). Our findings reveal the following: (1) Global Trends: During the reaction period, there was a notable decrease in human mobility globally, with a corresponding increase in residential behavior. However, during the adaptation period, apart from residential behavior, mobility in the remaining categories increased, particularly mobility in parks; (2) Regional Patterns: All continents experienced significant declines and fluctuations in human mobility behavior during the reaction period. In the adaptation period, Africa demonstrated more stable daily variations in the Fisher Information (FI) dynamic compared to other continents, while Asia showed relatively lower stability, marked by several sharp declines; (3) National Responses: Different countries and regions exhibited varying degrees of adaptation to changes in human mobility behavior. We categorized the 130 countries and regions into different categories based on their responses to these changes. This research aims to offer insights for policymakers in formulating strategies to address future unpredictable events.

Water-cooling-based and low-cost qPCR device for rapid nucleic acid analysis

Real-time quantitative PCR (qPCR) is a sought-after method for quantifying nucleic acids. A series of commercial instruments based on qPCR has been developed and applied to detect several diseases. However, commercial instruments have some limitations in terms of cost, bulk, and efficiency. Herein, we proposed a novel qPCR device using water-cooling technology to shorten the period of the PCR reaction. The device was made of an amplification module with a novelty water-cooling-based PCR chip, a custom-made fluorescence detection module, and a control module based on economical off-the-shelf electronics. All these modules were assembled in a 3D-printed frame with a size of 11 cm × 9.7 cm × 8.9 cm and a weight of 0.5 kg. With the help of water-cooling technology, the total time required to complete a PCR reaction was shortened, with a maximum cooling rate of 12 ℃/s, which is much faster than the rate of conventional cooling methods. Compared with commercial qPCR instruments, our device's cost, efficiency, and portability have been significantly optimized. To test the proposed device, a qPCR experiment was successfully performed with cDNA of Vesicular stomatitis virus at concentrations ranging from 0.005 μg/mL to 50 μg/mL.

Pathogenesis of Medication-Related Osteonecrosis of the Jaw: Odontogenic Infection-Preceding Type and Osteonecrosis-Preceding Type.

Introduction Medication-related osteonecrosis of the jaw (MRONJ) develops from odontogenic infection. However, there are also some cases of MRONJ developing from sites with no teeth, no root canal lesions, or no periodontal disease. This study aimed to retrospectively review radiographic images of MRONJ cases and examine the differences in characteristics between MRONJ suspected to be related to dental infection (odontogenic MRONJ) and MRONJ that occurred without dental involvement or of unknown cause (non-odontogenic MRONJ). Materials and methods One hundred and forty-five patients were diagnosed with MRONJat Kansai Medical University Hospital and Kansai Medical University Medical Center. The following variables were investigated: sex, age, primary disease, MRONJ site, body mass index, smoking habit, diabetes, corticosteroids, type of antiresorptive agent, administration period, CT findings (separation of sequestrum, osteolysis, periosteal reaction, and osteosclerosis), trigger, leukocytes, neutrocytes, neutrophil-lymphocyte ratio, serum albumin, and serum creatinine levels. Results In the univariate analysis, significant differences between odontogenic and non-odontogenic MRONJs were found in patients whose primary disease was malignancy, receiving denosumab (DMB), and with short administration period of antiresorptive agent, no osteolysis, periosteal reaction, and serum creatinine level. In multivariate analysis, non-odontogenic MRONJ was significantly more common in patients with no osteolysis and with periosteal reaction. Conclusion Non-odontogenic MRONJ tends to occur more frequently in patients treated with high-dose DMB, and there were significantly more cases of non-osteolytic MRONJ without radiographic evidence of osteolysis or with periosteal reactions.

Optical behavior, TL defect center analysis and photocatalytic characterization of Ag2O doped ZnO nano crystals

The objective of the study is to prepare Ag+-dopedZnO nano crystals and to assess their structure, optical behavior, TL analysis, photocatalytic activity. Using sol–gel technique the Ag+-doped ZnO nano crystals prepared. Using the FT-IR, XRD, BET surface area, SEM, EDX characterization techniques, we have examined the structure of the developed samples. The TL analysis of samples was done under a dose of 25 kGy gamma irradiation. Trap depth parameters of the samples evaluated. Which suggested the ZnO nano crystals doped with Ag+ ions are purely TL active. The optical studies such optical absorption, photoluminescence of samples reveal their optical behavior. The optical band gap of the samples also evaluated. Which is increasing with increase in concentration of Ag+ ions in ZnO nano crystals. Using the MV (10 ppm) and CR (10 ppm) dyes, under visible light the photocatalytic activity of the samples reported. At a reaction period of 90 min, the nano powdercontaining 1.0 mol% Ag+-dopedZnO nano crystals and a band gap energy of 2.75 eV demonstrated the best photocatalyticefficiency (∼91 %) in both colors. The evaluationwas done on the impact of radical scavenger research and catalyst dosage on degrading efficiency. The rate of reaction in the presence of 1.0 mol% Ag+-dopedZnO nano crystals was four times higher than the ZnO catalyst's rate constants, and the degradation reaction follows pseudo-first-orderkinetics. The degrading process shows pseudo-first-order kinetics, and the reaction rate was four times higher than the ZnO catalyst in the presence of 1.0 mol% Ag+-dopedZnO nano crystals. It took three cycle runs for the degrading efficiency to drop by 1 %. Thus, 1.0 mol% Ag+-dopedZnO nano crystals was employed as a promising photocatalyst with strong reusability potential for the degradation of textile colors, which will be very beneficial.

CO2-induced micro-mechanical alterations of mudstone Caprock: Examples from the Mercia Mudstone Group, East Irish Sea Basin

Mechanical properties of caprock are important for subsurface energy sequestration as they determine the rock stability under the influence of external forces. Despite some advantages, there is a lack of knowledge regarding the interplay between rock texture and mechanical properties and their impact on the caprock stability within a short-term fluid-rock reaction period. Typical caprock samples from the Mercia Mudstone Group in the East Irish Sea Basin are studied in this work. X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) were used to identify minerology and local heterogeneity characteristics. Nanoindentation tests were conducted before and after CO2-brine-rock reaction to investigate the changes of micro-mechanical properties. After CO2-brine treatment, significant dolomite dissolution was observed in all samples (although dolomite content was only minor in some samples). In contrast, the micro-texture of other minerals showed no significant changes indicating minimal to no dissolution at the current resolution. The changes of mechanical properties are lower than expected, which are probably related to the impaired cementation induced by the retained water in pore throats and relatively rough surface after reaction. For long-term carbon sequestration, the layered depositional characteristics of different phases may not only form a barrier to prevent fluids leaking upward, but also complement each other in mechanical properties to maintain stability. This study improves the understanding of the effect of microscale structural and micro-mechanical changes on caprock stability in carbon sequestration related applications.

Walker’s Appeal... is the main manifesto of radical African-American abolitionism

This work is about one of the key episodes of African-American history and the history of American abolitionism associated with the publication in September 1829 in Boston of Walker’s Appeal, in Four Articles; Together with a Preamble, to the Coloured Citizens of the World. The appearance of this “revolutionary appeal” undoubtedly marked a new milestone in the development of the anti-slavery movement and the actual emergence of such a trend as radical African-American abolitionism. The reaction to the release of this document by the authorities of the Southern States can be called unprecedented in its scale and consequences. It found expression in the adoption of a number of repressive laws, which, in turn, marked the beginning of a period of prolonged reaction in the American South, which would end only after the end of the Civil War of 1861–1865. The significance of this event is difficult to overestimate. After almost two centuries, the figure of David Walker and his Appeal still arouse increased interest from Western researchers and not only. However, no serious works on this topic have been published in Russian historiography up to the present moment. This study aims to identify and examine the causes and circumstances of the writing of the Walker’s Appeal…, to analyze the main provisions of this document and the consequences caused by its dissemination. In addition, the author pays special attention to the review of the historiography of this issue. The source base is newspaper publications, letters and bills of the period under review, as well as the text of the Appeal. The methodological basis of the research consists of causal, historical-descriptive, historical-genetic, historical-typological, retrospective, and comparative-historical methods. The materialistic dialectic plays the main role, showing the development of the abolitionist movement in dynamics and the influence of related factors. The author concludes that Walker’s Appeal… became an expression of the most important trend in the development of American abolitionism at the end of the first third of the nineteenth century. The appearance of this document clearly demonstrated the radicalization of the African-American community itself and its willingness to join the struggle for the abolition of slavery and its rights.

Ultrasound and microwave extraction from Moringa oleifera Lam.: Characterization and antiproliferative effect

Moringa oleifera has been a focus of interest because of the different properties (anticancer, antioxidant, etc.) that have been attributed to this plant. However, the most used methodology is soxhlet, which requires long periods of reaction (18 hours), generating greater energy expenditure. Recently, green extraction technologies have been developed like ultrasound and microwaves, reducing reaction time by up to 97%. The objectives of this study were to extract and identify the polyphenolic compounds present in aqueous and hydro-alcoholic extracts from Moringa oleifera dried leaves using ultrasound and microwave, as well as to evaluate their in vitro cytotoxic effect using cancer and non-cancer cells. A combination of ultrasound and microwave was utilized to extract polyphenolic compounds from Moringa dried leaves. HPLC–MS analysis was conducted to qualitatively identify the polyphenols in the samples. The cytotoxic effect was evaluated by MTT and comet assays using non-cancer (3T3, Hek293, and Vero) and cancer (HepG2) cells lines. Results: 30 polyphenolic compounds from 9 different families were identified by HPLC. Data suggested that hydro-alcoholic extracts from Moringa leaves have potent cytotoxic activities in a depend-doses response. Also, compounds from aqueous extracts did not cause cell death, while polyphenol extract from hydro-alcoholic extracts decreased populations in both cancer and non-cancer cell lines measurement by MTT. HepG2 cells showed DNA damage by comet assay. The extraction using ultrasound and microwaves at 30 minutes of reaction has an antiproliferative effect through apoptosis in cancer cells, in addition ethanolic extracts have higher cytotoxicity compared to aqueous extracts.

Self-healing of active site in Co(OH)2/MXene electrocatalysts for hydrazine oxidation

The development of efficient hydrazine oxidation reaction (HzOR) catalysts is important for the construction of remarkable energy storage and conversion systems. However, after a period of electrochemical reaction, the active site of the catalyst will be irreversibly reduced or inactivated, and how to recover the active site is a major challenge. Here, we report 2D Co(OH)2/Ti3C2(OH)x MXene composites with rapid reconstruction and self-healing behaviors as efficient and stable electrocatalysts during HzOR process. Both experimental and theoretical results indicate that the introduction of Ti3C2(OH)x MXene can effectively reduce the dehydrogenation barrier of Co(OH)2, from 0.584 eV to 0.481 eV to form the real catalytic active center Co(OH)O. Subsequently, Co(OH)O/Ti3C2(OH)x MXene composites with metal-like conductivity not only present spontaneous adsorption capacity of N2H4, but also can modulated rate-determining step of dehydrogenation of *N2H4 to *N2H3 (0.54 eV) compared with Co(OH)O. Finally, the electrophilic oxygen of Co(OH)O/Ti3C2(OH)x can spontaneously obtain electrons and protons from N2H4, achieving the oxidation of N2H4 while reducing Co(OH)O to Co(OH)2, thus completing the self-healing of the efficient catalyst.

Retardation mechanism of phosphogypsum in phosphogypsum-based excess-sulfate cement

The effect of phosphogypsum (PG) on the hydration and retardation mechanism of phosphogypsum-based excess-sulfate slag cement (PESC) was mainly investigated. Based on the natural characteristics of PG, such as low pH value and the presence of soluble phosphorus impurities, the content of PG passing the 4.75 mm standard sieve was used as a variable to study the retardation mechanism of PG on PESC. It can be inferred from the heat flow and cumulative heat flow that the induction period is significantly prolonged with the content of PG, which is also reflected in the increase of the setting time of PESC. In the early period of hydration, as the content of PG increases, the soluble phosphorus concentration increases, and the pH value decreases. The changes in soluble phosphorus concentration and pH value affect the microstructure and amount of hydrates. Combined with experimental results, it has been demonstrated that the delay in the hydration of PESC by PG content is mainly due to: the excessive dissolution of Ca2+ and SO42- promotes the recrystallization of dihydrate gypsum; the dissolution of soluble phosphorus reduces the pH value in the pore solution and forms precipitates of calcium phosphate and hydroxyapatite; in the initial reaction period, a large amount of ettringite and C-S-H gel precipitate to form a protective film; the decrease in pH value leads to a decrease in carbonization resistance, and CO2 in the air is more likely to attack the PESC paste, react with alkaline substances in PESC, or degrade hydrated C-S-H and ettringite. The above factors all lead to a decrease in exchangeable ions during the hydration, thereby prolonging the setting of PESC.