Dichloromethane Research Articles

Simultaneous ammonia recovery and treatment of sludge digestate using the vacuum stripping and absorption process: Scale-up design and pilot study

The paradigm of wastewater treatment is shifting from costly pollutant removal in mainstream to resource recovery from sidestream. This paradigm shift, nevertheless, is retarded by the lack of scalable, cost-effective ammonia recovery technologies. The vacuum stripping and absorption (VaSA) process has unrivaled features to recover ammonia and treat digestate simultaneously. The present study introduced a multi-pool boiling mode of vacuum stripping for scale-up design and conducted pilot tests at a water resource recovery facility using a 250-L/batch 3-pool system. It stripped 80.7 % of ammonia in sludge digestate and 91.5 % in pressate in 5-h batch operation. Ammonia mass transfer coefficient reached 0.319–0.485 1/h in digestate and 0.386–0.608 1/h in pressate. The operating challenge was to properly maintain vacuum and configure the demister where vapor–liquid equilibrium changed as it was scaled up. In contrast to the optimum vacuum pressure of 25–27 kPa and feed boiling temperature of 65 °C in the single-pool boiling stripper, the vacuum pressure in the 3-pool boiling stripper was increased to 46.3–46.9 kPa by the higher demister temperature (74 °C). The recovered crystals contained 98.4–103.7 % of (NH4)2SO4. Vacuum-assisted alkali/thermal treatment of digestate under the VaSA conditions increased the dissolved fraction of volatile solids from 7.5 % to 32.8–34.1 % and decreased fecal coliform to mostly undetected. Solids solubilization also resulted in generation of volatile organic compounds, primarily allyl chloride, methylene chloride, 2,5-octadecadiynoic acid methyl ester, and (E)-1,2-dichloroethylene. The low concentrations and small vapor pressures of these compounds were unfavorable for co-stripping. The co-stripped compounds were largely retained in condensate and absent in vacuum exhaust. This study validated the scalability of multi-pool boiling design of VaSA for efficient ammonia recovery and elucidated the effects on digestate treatment.

A remarkable improved Li+/Mg2+ selectivity and Li+ recovery simultaneously by adding crown ether to tributyl phosphate-ionic liquid extraction system as co-extractant

The high similarity in chemical properties between Li+ and Mg2+ poses a substantial challenge for their selective separation from salt lake brine with high Mg-Li (m/m) ratios. Herein, a highly efficient solvent extraction system was reported for Li+/Mg2+ selective separation, with tributyl phosphate (TBP) and di(aminobenzo)-14-crown-4 (CE) as extractants, [C4mim][NTf2] (IL) as co-extractant, and methylene chloride as a diluent. Simulated brines included 0.01 M LiCl and 0.01 and 0.2 M MgCl2 with Mg/Li mass ratios of 3.5 and 70, respectively. Molecular dynamics (MD), density functional theory (DFT), and 1H NMR analysis were employed to reveal the hydrogen bond interaction and compatibility between CE, TBP, and IL. Under the optimal extraction conditions containing a concentration of 20 mg/mL CE and 0.61 mmol/mL IL, the maximum single-stage Li+ extraction rate of the TBP-CE-IL extraction system with Mg/Li mass ratios of 3.5 and 70 were 89.5 and 81.8 %, and the separation factor of Li to Mg were up to 515 and 422. Compared with the TBP-IL extraction system, the addition of CE effectively improved the extraction rate of Li+ and the selectivity of Mg-Li, which was due to the hydrogen bond interaction between CE and TBP/IL and the cavity size effect between CE and Li+, improving CE coordination and endowing the complex generated in the organic phase with greater stability. The possible structure of the complex in the organic phase was determined to be 2TBP·Li·NTf2-CE·Li·NTf2 through Li+ extraction dynamic analysis. In summary, this work provides an efficient separation technology for Li+ extraction from salt lake brine.

Evaluation of Stability and TLC Fingerprinting of the Artemether Component in Artemether-Lumefantrine Combination Suspension Formulations Available in Nigeria Pharmaceutical Market

Aim: Artemether is the main component of the artemisinin-based combination therapy (ACT), used in the management of malaria infection caused by Plasmodium falciparum. Hence, its stability and conformation to pharmacopeia standards are necessary for use. The study aimed to review the first-order derivative spectrophotometric method for simultaneous estimation of artemether and its derivatives in pure and combined formulations, and their stability profiles, then develop a simple, precise, and fast technique for their rapid physicochemical analysis.
 Methodology: Thin-layer chromatographic (TLC) Fingerprinting principles were used in the analysis. Artemether and its derivatives were spotted on the TLC chromatograms after adding 25 mL of the suspension to a mixture of 100 mL of distilled water and 4 mL of NaOH, extracting the mixture with 60 mL of dichloromethane (DCM), drying, and sonicating the residue with 20 mL of the solvent. It was centrifuged, and the clear supernatant was spotted on the TLC plates.
 Results: The color test results revealed the presence of the artemether compound in the reference standard as well as the six brands of suspensions (A, B, C, D, E, and F) utilized in the study. Artemether melting point was obtained between 86 - 89 °C; within the International Pharmacopeia specified range. The chromatograms of Artemether and derivatives showed Rf values of 0.25 (impurity A), 0.3 (artenimol impurity B), 0.35 (impurity C), 0.4 (α-artemether: impurity D), and 0.55 (artemether).
 Conclusion: The devised method can be applied to the routine quality control analysis of artemether-lumefantrine suspension in addition to existing analytical techniques.

Evaluation of alternate hosts for recombinant expression of a reductive dehalogenase

Organohalides are recalcitrant, toxic environmental pollutants. Reductive dehalogenase enzymes (RDases) found in organohalide respiring bacteria (OHRB) utilise organohalides as electron acceptors for cellular energy and growth, producing lesser-halogenated compounds. Consequently, microbial reductive dehalogenation via organohalide respiration represents a promising solution for clean-up of organohalide pollutants. Dehalobacter sp. UNSWDHB is an OHRB capable of respiring highly toxic chloroform (CF) and converting it to dichloromethane (DCM). TmrA has been identified as an RDase responsible for this conversion and different strategies for generation of functional recombinant TmrA is the focus of this article. In this study, TmrA was recovered from inclusion bodies expressed in E. coli and refolded in the presence of FeCl3, Na2S and cobalamin to yield functional enzyme. TmrA has been previously expressed in a soluble and functional form in the corrinoid-producing Bacillus megaterium. Using a fractional experimental design for cultivation and induction combined with purification under anaerobic conditions resulted in substantially higher activity of recombinant and native TmrA than previously reported. TmrA was then expressed in a soluble and active form in Shimwellia blattae. Co-expression with two different putative chaperone proteins from the original host did not increase the level of soluble expression in S. blattae, however activity assays showed that removing the TAT signal from TmrA increases the dechlorination activity compared to when the TAT signal is present. Finally, TmrA was successfully expressed in a soluble and active form in the H2-oxidizing C. necator H16, a novel host for the expression of RDases.

Evaluation of Antioxidant, Antidiabetic, and Cytotoxic Activities of Lilium nepalense D. Don

Lilium nepalense, a temperate medicinal plant, is used as a diuretic, antipyretic, tonic, flavoring agent, and heart pain treatment. This research aimed to evaluate the in vitro antioxidant and antidiabetic activities of the methanol, dichloromethane (DCM), and hexane fractions, and in vivo cytotoxic activities of the crude extracts of the bulb. The antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, antidiabetic activity by α-glucosidase inhibitory assay, and cytotoxic activity in terms of LC50 (median lethality concentration) by Brine shrimp assay. The DCM fraction showed the strongest antioxidant activity (IC50=134.99±9.75 µg/mL) and highest antidiabetic activity (IC50=182.01±20.50 µg/mL) than other fractions. Similarly, the DCM fraction had the highest total phenolic contents (243.97±33.78 mg of gallic acid equivalent per gram dry weight) and highest flavonoid contents (7.68±0.85 mg of quercetin equivalent per gram dry weight) than other fractions. Moreover, the crude extract of the bulb was not found to be cytotoxic to the Brine shrimp nauplii (LC50=3.83 mg/mL). It is the first report to date describing the antioxidant, antidiabetic, and cytotoxic properties of L. nepalense. This study concludes that the DCM fraction of the bulb could be used as an antioxidant and antidiabetic agent for therapeutic purposes; however, further identification and characterization of bioactive compounds responsible for the antioxidant, antidiabetic, and cytotoxicity is required for further validation.

Antimicrobial Cyclic Dipeptides from Japanese Quail (Coturnix japonica) Eggs Supplemented with Probiotic Lactobacillus plantarum.

Fifteen cyclic dipeptides (CDPs) containing proline, one cyclo(Phe-Ala) without proline, and a non-peptidyl DL-3-phenyllactic acid were previously identified in the culture filtrates of Lactobacillus plantarum LBP-K10, an isolate from kimchi. In this study, we used Japanese quail (Coturnix japonica) eggs to examine the effects of probiotic supplementation on the antimicrobial CDPs extracted from quail eggs (QE). Eggshell-free QE were obtained from two distinct groups of quails. The first group (K10N) comprised eggs from unsupplemented quails. The second group (K10S) comprised eggs from quails supplemented with Lb. plantarum LBP-K10. The QE samples were extracted using methylene chloride through a liquid-liquid extraction process. The resulting extract was fractionated into 16 parts using semi-preparative high-performance liquid chromatography. Two fractions, Q6 and Q9, were isolated from K10S and identified as cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro). The Q9 fraction, containing cis-cyclo(L-Leu-L-Pro), has shown significant inhibitory properties against the proliferation of highly pathogenic multidrug-resistant bacteria, as well as human-specific and phytopathogenic fungi. Some of the ten combinations between the remaining fourteen unidentified fractions and two fractions, Q6 and Q9, containing cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro) respectively, demonstrated a significant increase in activity against multidrug-resistant bacteria only when combined with Q9. The activity was 7.17 times higher compared to a single cis-cyclo(L-Leu-L-Pro). This study presents new findings on the efficacy of proline-containing CDPs in avian eggs. These CDPs provide antimicrobial properties when specific probiotics are supplemented.

In silico and in vitro assessment of the anti-β-amyloid aggregation and anti-cholinesterase activities of Ptaeroxylon obliquum and Bauhinia bowkeri extracts

BackgroundAlzheimer’s disease (AD) is the most common form of dementia and dementia constitutes the fifth leading cause of mortality across the globe. Available treatment modalities and drugs have abysmally failed to curtail AD. This study evaluated the mitigation of Aβ aggregation and anti-cholinesterase activities with the crude extracts of Ptaeroxylon obliquum and Bauhinia bowkeri. Computational studies of the most abundant phytochemicals from the crude extracts of both plants with proteins were investigated. The phytochemical composition of the different crude extracts (hexane, DCM, and ethanol) of the plants were analyzed with FTIR and GC-MS. The inhibitory potential of the extracts on BACE-1 and cholinesterase activities was determined with both computational molecular docking studies and in vitro enzyme assays. Their anti-aggregation properties were confirmed with Thioflavin-T assay and TEM. ResultsThe in silico studies revealed that though thunbergol and cyclotetradecatriene (the major constituents of the extracts) inhibited all the proteins, the latter exhibited the best inhibitory potential. The in vitro results showed that while the dichloromethane (DCM) extract of P. obliquum had the highest butyrylcholinesterase (BuChE) inhibitory activity (1.77 µg/ml), the hexane and ethanol extract of B. bowkeri exhibited the highest β-site amyloid precursor cleaving enzymes-1 (BACE-1) (30.4 µg/ml) and acetylcholinesterase (AChE) (58.11 µg/ml) inhibitory efficacy, respectively. The ethanol extract (160 μg/ml) of B. bowkeri had the most efficacious anti-aggregation activity. ConclusionsThis study suggests that the plants could possess neuroprotective effects and could also be sources of anti-AD novel drugs.How to cite: Ojo MC, Mosa RA, Osunsanmi FO, et al. In silico and in vitro assessment of the anti-β-amyloid aggregation and anti-cholinesterase activities of Ptaeroxylon obliquum and Bauhinia bowkeri extracts. Electron J Biotechnol 2024;68. https://doi.org/10.1016/j.ejbt.2023.11.004.

Effects of preparation method on thermoelectric properties of poly(aniline‐co‐3,4‐ethylenedioxythiophene)/SWCNT composites

AbstractComposites of conducting polymer and single‐walled carbon nanotubes (SWCNTs) are attracting great attentions in harvesting low‐grade waste heat. Prefabricated SWCNTs film used as the working electrode was placed at the liquid interface between the inorganic phase (dilute sulfuric acid solution) and the organic phase consisting of dichloromethane (DCM), aniline (ANI), and 3,4‐ethylenedioxythiophene (EDOT), together with a platinum wire (the counter electrode) and a silver chloride (AgCl/Ag) electrode (the reference electrode), to perform electrochemical polymerization of ANI and EDOT at the liquid interface. Thermoelectric (TE) composites of poly(ANI‐co‐EDOT) and SWCNTs were produced. Compared with composites from ultrasonic mixing and coating methods, the 10 wt% SWCNTs‐composites in situ formed in electrochemical polymerization have the highest power factor (PF) of 41.56 ± 3.58 μW m−1 K−2, higher than the PF values of the composites formed by other two methods. The work indicates that the TE properties of ANI‐EDOT copolymer/SWCNT (poly[ANI‐co‐EDOT]/SWCNT) composites prepared by electrochemical polymerization were better than those of the composites obtained by physical mixing the electrochemically synthesized poly(ANI‐co‐EDOT) with SWCNTs. Moreover, SWCNTs treated with sodium dodecylbenzene sulfonate (SDBS) could further improve the TE properties of the composites.

ESTERIFICATION OF BETULIN 3-ACETATE IN MELTS OF THE MALEIC AND LEVULINIC ACIDS

Esters of betulin containing residues of bioactive aromatic and aliphatic acids are of interest to the chemical and pharmaceutical industry as hepatoprotectors, anti-inflammatory, antiulcer and immunomodulatory substances. The development of new efficient, ecological and economical methods for the synthesis of betulin esters is an actual task. A new "green" method for the production of betulin 3-acetate-28-maleate and betulin 3-acetate-28-levulinate has been developed. For the first time, esterification of betulin 3-acetate with melts of maleic acid and levulinic acids was carried out at a temperature of 185-200°C for 5-7 minutes to obtain betulin 3-acetate-28-maleate and betulin 3-acetate-28-levulinate, respectively. The structure of the resulting betulin esters was determined using IR and NMR spectroscopy, and the composition was determined by elemental analysis. The advantage of the developed method for the synthesis of 3-acetate-28-maleate and 3-acetate-28-levulinate of betulin in comparison with the known ones is: the synthesis is carried out in the absence of harmful and hazardous solvents (pyridine, methylene chloride, chloroform), a reduction in the duration of synthesis from 15-40 hours to 5-7 minutes. Maleic anhydride is used instead of maleic anhydride on the preparation of betulin 3-acetate-28-maleate.

Characterization of the Reversible Intersystem Crossing Dynamics of Organic Photocatalysts Using Transient Absorption Spectroscopy and Time-Resolved Fluorescence Spectroscopy.

Thermally activated delayed fluorescence (TADF) emitters are molecules of interest as homogeneous organic photocatalysts (OPCs) for photoredox chemistry. Here, three classes of OPC candidates are studied in dichloromethane (DCM) or N,N-dimethylformamide (DMF) solutions, using transient absorption spectroscopy and time-resolved fluorescence spectroscopy. These OPCs are benzophenones with either carbazole (2Cz-BP and 2tCz-BP) or phenoxazine/phenothiazine (2PXZ-BP and 2PTZ-BP) appended groups and the dicyanobenzene derivative 4DP-IPN. Dual lifetimes of the S1 state populations are observed, consistent with reverse intersystem crossing (RISC) and TADF emission. Example fluorescence lifetimes in DCM are (5.18 ± 0.01) ns and (6.22 ± 1.27) μs for 2Cz-BP, (1.38 ± 0.01) ns and (0.32 ± 0.01) μs for 2PXZ-BP, and (2.97 ± 0.01) ns and (62.0 ± 5.8) μs for 4DP-IPN. From ground state bleach recoveries and time-correlated single photon counting measurements, triplet quantum yields in DCM are estimated to be 0.62 ± 0.16, 0.04 ± 0.01, and 0.83 ± 0.02 for 2Cz-BP, 2PXZ-BP, and 4DP-IPN, respectively. 4DP-IPN displays similar photophysical behavior to the previously studied OPC 4Cz-IPN. Independent of the choice of solvent, 4DP-IPN, 2Cz-BP, and 2tCz-BP are shown to be TADF emitters, whereas emission by 2PXZ-BP and 2PTZ-BP depends on the molecular environment, with TADF emission enhanced in aggregates compared to monomers. Behavior of this type is representative of aggregation-induced emission luminogens (AIEgens).

MYCELIAL GROWTH KINETICS, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF A SUBMERGED CULTURE OF THE MEDICINAL FUNGI GANODERMA RESINACEUM GA1M ISOLATED FROM BULGARIA

The aim of this study was the evaluation of the basic bioprocess parameters by applying mathematical modelling of the growth kinetics of Ganoderma resinaceum GA1M isolated from Bulgaria as well as assessment of the antioxidant and antimicrobial activity of the obtained biomass. The models of Monod, Moser, Andrews and Verhulst in combination with the Luedeking–Piret were applied for kinetics modelling of the cultivation process. The in vitro antioxidant activity was evaluated by applying four different methods. The disk diffusion method and broth microdilution methods were employed to determine the antimicrobial activity of the mycelium biomass extracts. Mathematical modeling of the kinetics of the cultivation process was performed and basic bioprocess parameters were determined. The obtained experimental data were in agreement with the applied mathematical models. The water extract of the mycelium biomass showed the highest antioxidant potential and the highest total phenolic content. The methylene chloride, methanol and ethanol extracts of the biomass demonstrated antimicrobial activity.

Chemical depolymerization of cork suberin with hydrothermal processes

This study presents for the first time results on hydrothermal treatments (autohydrolysis) of cork to assess their chemical effect on its structural components, namely on suberin. Extractive-free cork was autohydrolysed in isothermal conditions with a broad range of severity factors (SF) of 2.1–4.7 (120–180 °C, 60–240 min) determining mass loss and chemical changes in cork, namely on suberin content and composition. Mass loss was small for milder conditions, and increased steadily with severity e.g. 4.0% for SF 3.0, 9.8% for SF 3.8, 14.1% for SF 4.6. However, mass loss of cork by autohydrolysis is much smaller than that of lignocellulosic biomass under comparable treatment severity. Until SF 3.0, little chemical changes were seen, with SF 3.3–4.1, the autohydrolysed cork showed higher dichloromethane (DCM) solubles and suberin, and less polysaccharides, while for the most severe conditions (SF 4.4–4.7), there was a substantial increase of DCM solubles, a downfall in suberin and polysaccharides, and an unaltered lignin content. Cork polysaccharides decreased steadily with SF increase by hydrolysis of hemicelluloses, e.g. 7.1% of cork for SF 3.5% and 3.9% for SF 4.7. Suberin was maintained in cork until SF 4.4 without changes in composition, but decreased subsequently e.g. at SF 4.7, suberin represented 47% of the initial untreated cork (56% in the initial cork) and showed less ω-hydroxy acids and more α,ω-diacids. The amount and composition of suberin and DCM solubles in the autohydrolysed cork under the various reaction severities allow concluding that suberin is stable until 160 °C but depolymerizes at higher temperatures by ester bond cleaving mostly of mono-functional long-chain monomers. Overall cork showed higher hydrothermal stability than lignocellulosic materials.

Dual Benefits of Hydrogel Remediation of Cadmium-Contaminated Water or Soil and Promotion of Vegetable Growth under Cadmium Stress.

This study aims to solve the problem of cadmium heavy metal ion pollution caused by the abuse of chemical fertilizers and activities such as mining, which pose a serious threat to the plant growth environment. We successfully synthesized DMAPAA (N-(3-(Dimethyl amino) propyl) acrylamide)/DMAPAAQ (N, N-Dimethyl amino propyl acrylamide, methyl chloride quaternary) hydrogels via free radical polymerization. Subsequently, we conducted experiments on this hydrogel for growing vegetables under cadmium stress conditions in aqueous solutions and soil. The cadmium capture capacity of DMAPAA/DMAPAAQ hydrogels under different cadmium ion concentrations and pH values was evaluated by using inductively coupled plasma optical emission spectrometry (ICP). The research results show that under the condition of pH = 7.3, the cadmium capture capacity of DMAPAA/DMAPAAQ hydrogels is the greatest. We used the Langmuir model to fit the adsorption data, and the correlation coefficient was as high as 0.96, indicating that the model fits well. The application of the hydrogels promoted the growth of vegetables in soil under cadmium stress conditions. The results showed that when the added amount of hydrogel was 4%, the dry weight of the vegetables was the largest. In addition, when the added amount of cadmium was 500 mg/kg and the added amount of hydrogel was 4%, the absorption of cadmium by the vegetables decreased to an undetectable level. In summary, the hydrogel successfully synthesized in this study can be effectively used to immobilize cadmium ions in soil while positively promoting the growth and yield of vegetables. This achievement has practical significance for solving the problem of heavy metal ion pollution.

Vacuum Ultraviolet Photolysis of Condensed Methyl Chloride in Interstellar Model Conditions and Trapping of Intermediates at Intergrain Interfaces

Vacuum Ultraviolet Photolysis of Condensed Methyl Chloride in Interstellar Model Conditions and Trapping of Intermediates at Intergrain Interfaces

An Alternative to Chlorobenzene as a Hole Transport Materials Solvent for High-Performance Perovskite Solar Cells

Spiro-OMeTAD is a widely used hole-transporting layer (HTL) material, characterized by high hole mobility and good film-forming properties, in perovskite solar cells (PSCs). However, this material has high synthesis costs, low solubility, dependence on hygroscopic dopants, and a low commercial potential. Recently, we investigated alternative materials with good solubility, simple synthetic methods, and good electrical characteristics for use as hole transport materials (HTM) in triple-cation PSCs. Herein, (E,E,E,E)-4,4′,4″,4′″-[Benzene-1,2,4,5-tetrayltetrakis(ethene-2,1-diyl)]tetrakis[N,N-bis(4-methoxyphenyl)aniline], which has a small molecular weight and similar properties to Spiro-OMeTAD, was assessed for use as a HTM via a pre-test of device performance, including its electrical properties, surface morphology, and coating process method, with PSC efficiencies routinely surpassing 20%. A remarkable open-circuit voltage of 1.111, along with a photovoltaic efficiency of 20.18% was obtained in PSCs using this HTM with dichloromethane (DCM) instead of chlorobenzene, indicative of its potential for the fabrication of resistance components with improved surface uniformity. These results provide insights into DCM as an efficient solvent for small molecule-based HTM.

Identifying edible plants with high anti-obesity potential: In vitro inhibitory effect against pancreatic lipase followed by bioactive compound metabolomic screening

The ever-growing number of individuals facing obesity related health problems represents an alarming situation. Within the available obesity control strategies, there is evidence that some natural compounds can inhibit pancreatic lipase (PNLIP, EC 3.1.1.3), a digestive enzyme with pivotal role in the hydrolysis of dietary triacylglycerols, resulting in reduced fat metabolism. In this study, to identify sources of bioactive compounds with anti-obesity potential, 278 extracts originating by 126 food species were prepared in water and dichloromethane (DCM) and their in vitro inhibitory potential against PNLIP was measured. Importantly, 12 extracts exceeded the set cut-off level of significant inhibitory effect (inhibition> 70%) and for them dose-response curves were prepared and metabolomic target screening was performed. By using ultra-high-performance liquid chromatography hybrid quadrupole time-of-flight mass spectrometry (UHPLC-q-TOF-MS), it was possible to tentatively identify 28 and 22 secondary metabolites in the aqueous and DCM extracts, respectively. Several species-specific compounds were detected, e.g., hesperidin and eriocitrin in lemon and lime fruit aqueous extracts or curcuminoids in DCM turmeric extracts. Additionally, the highest percentage of the total analytical signal detected in dill, walnut, caper and bell pepper DCM extracts corresponded to various fatty acids. All in all, the edible plant extracts with strong anti-obesity potential contained various bioactive phytochemicals that may be used in nutraceutical applications.

Ce-modified USY zeolite catalysts for catalytic oxidation of chlorinated VOCs: Effect of the location of CeO2 and its synergistic effect with USY zeolite

The catalytic behavior of a catalyst for chlorine-containing volatile organic compounds (CVOCs) oxidation largely depends on the synergistic interaction between the oxidizing and acidic sites. In the present work, two catalysts with different distributions of CeO2 on the inner and outer surfaces of 4.0Ce-USY-ex and 4.0Ce-USY-dp (USY zeolite) were prepared respectively by ion exchange and deposition methods, with a purpose of finding out how the location of the oxidation sites (CeO2) influence its synergistic effect with the acidic sites of zeolite. The results show that 4.0Ce-USY-ex is much more active for catalytic degradation of 1,2-dichloroethane (DCE), while 4.0Ce-USY-dp catalyst exhibit higher catalytic degradation activity for other structured CVOCs (dichloromethane (DCM), trichloroethylene (TCE), chlorobenzene (CB)). CeO2 in 4.0Ce-USY-ex catalyst mainly disperses in the pore channels of USY zeolite, and there are many strong acid centers on the surface, which is conducive to the dechlorination conversion of CVOCs. However, CeO2 in 4.0Ce-USY-dp catalyst is mainly distributed on the outer surface of USY and has strong oxidation ability, which contributes to the deep oxidation of CVOCs. Moreover, the presence of a large number of strong acid centers on the catalyst surface of 4.0Ce-USY-ex catalysts leads to severe accumulation of surface carbon species and significantly decreases its stability towards DCE. However, a large number of active oxygen species on the surface of 4.0Ce-USY-dp and CeO2 catalysts are beneficial to the deep oxidation of DCE, reducing the formation of surface carbon and thus improving the stability of the catalyst. Thus, the influence of the location of the oxidation sites on its synergistic effect with the acidic sites was established in the present work, which could provide some new ideas for the rational design of CVOCs degradation catalyst with appropriate distribution of active sites.

Polarity responsive polysiloxanes with twisting intramolecular charge transfer effect for monitoring lipophagy process and the detection of volatile organic compounds

Polarity plays a critical role in biology and materials science, serving as a complex parameter. Imbalances in polarity within subcellular organelles are closely associated with various diseases. Moreover, volatile organic compounds (VOC) with low polarity pose significant health and safety risks, therefore, researchers have shown great interest in accurately detecting polarity. However, precise observation of polarity changes within organisms and identification of low-polarity volatile organic solvents are formidable challenges. To overcome these difficulties, we developed a versatile polymeric twisting intramolecular charge transfer (TICT) effect Polysiloxane-n (PDMS-n), utilizing polysiloxane molecular chains as "smart guides" to connect TICT molecules, inspired by the concept of "threading a needle." With the aid of PDMS-n, the process of polarity changes during cellular lipophagy was monitored in situ with high accuracy. Remarkably, the polarity changes of the local microstructure of the PDMS films were successfully visualized. PDMS-Films were also constructed, which enabled the recognition of Dichloromethane (DCM) gas during swelling. This work will contribute to the understanding of changes in cellular physiological processes, and facilitate the sensitive detection of VOCs.

In vitro antioxidant and anticholinesterase activity of Aegle marmelos fruit: implications for Alzheimer’s disease treatment

AbstractBackgroundIncreased antioxidant and anticholinesterase activity are key pathological hallmarks of Alzheimer’s disease (AD). In various Ayurvedic formulations Aegle marmelos (AM) belonging to family Rutaceae have traditionally been used as a brain tonic. However, there was no scientific validate proof of it. Hence, the present study was aimed to identify bioactive extract/fraction/constituent of AM fruit having potential to treat AD.MethodFour different crude extracts of AM fruits by using different solvents on basis of increasing polarity‐such as petroleum ether, chloroform, methanol and distilled water‐by successive Soxhlet extraction were prepared and evaluated for in‐vitro antioxidant and anticholinesterase inhibition assay by using DPPH and Ellman’s assay respectively. Most bioactive extract was further subjected to fractionation by using solvent‐solvent partioning followed by flash chromatography for further sub fractionation of most bioactive fraction. Total phenolic (TPC) and flavonoid content (TFC) was also calculatedResultComparative evaluation of all four prepared extracts for in‐vitro antioxidant and anticholinesterase inhibition assays showed that the methanol extract (ME) was most bioactive. Furthermore, bioactivity‐guided fractionation of this bioactive ME revealed that Dichloromethane (DCM) fraction evinced highest antioxidant and anticholinesterase activity with IC50 value 74.56±1.43 µg/ml and 47.65±2.76 µg/ml due to presence of higher phenolic and flavonoid content. However, further sub‐fractionation of DCM fraction showed significantly higher IC50 values thus decreased activity.ConclusionThis preliminary study clearly suggested that the DCM fraction from the ME of A. marmelos may prove to be potential candidate for the treatment of AD may be due to synergistic effect of phenolic and flavonoid content present in it. However, to validate the neuroprotective effect of DCM fraction of AM fruit against AD further exploration at cellular and molecular level is required to underlying its pharmacological mechanism as well as identification of the active phytoconstituents responsible for anti‐Alzheimer’s effect.

Molecular Docking, Synthesis and Antimicrobial Evaluation of 4-[(3 hydroxybenzalidene)amino]antipyrine and its Copper Complex

The synthesis and characterization of Schiff base-containing transition metal complexes have gained increasing importance due to their catalytic roles in various reactions and their biological activities. These metal complexes have become crucial in drug design, leading to a growing interest in metal-based drugs. The study aimed to synthesize copper metal complex with a new Schiff base ligand 4-[(3-hydroxybenzalidene)amino]antipyrine derived from 4-aminoantipyrine and 3-hydroxybenzaldehyde, as well as evaluate their antimicrobial activity against gram positive and gram-negative bacterial strains. The ligand and its copper complex were assessed for antimicrobial activity against gram-positive and gram-negative strains utilizing disc diffusion and broth dilution methods. Spectroscopic techniques (UV-Vis, FT-IR, XRD, and EDXRF), solubility tests, and elemental analysis were employed to investigate the ligand and copper complex. The ligand displayed high insolubility in various solvents but had limited solubility in chloroform and methyl chloride. The FTIR spectrum of the Schiff base reveals the presence of aromatic hydrocarbons, imine (C=N), hydroxyl (-OH), secondary amine (C-N), carbonyl (C=O), and vibrations associated with C-O and C-C bonds, reflecting its molecular structure. In the EDXRF analysis, a prominent peak at 7.80 keV corresponding to copper was detected, indicating that copper is the most abundant element found in the ligand. XRD analysis demonstrated distinct crystal structures for both the ligand and its copper complex. The UV-Vis spectra of the ligand exhibited an absorption peak at a UV lambda max of 220 nm, indicating a π→π* transition. In contrast, the absorption peaks observed in the copper complex indicated different transitions compared to the Schiff base. The MIC results indicated the copper complex's stronger antimicrobial activity than the Schiff base against tested bacteria. Molecular docking studies showed that the interaction energies of the synthesized compounds, particularly the ligand and copper complex, surpassed that of the well-known anti-diabetic drug, metformin.