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Less Is More: Selective-Atom-Removal-Derived Defective MnO Catalyst for Efficient Propane Oxidation.Nanomaterials (Basel, Switzerland) May 2024Defect manipulation in metal oxide is of great importance in boosting catalytic performance for propane oxidation. Herein, a selective atom removal strategy was...
Defect manipulation in metal oxide is of great importance in boosting catalytic performance for propane oxidation. Herein, a selective atom removal strategy was developed to construct a defective manganese oxide catalyst, which involved the partial etching of a Mg dopant in MnO. The resulting MgMnO-H catalysts exhibited superior low-temperature catalytic activity (T = 185 °C, T = 226 °C) with a propane conversion rate of 0.29 μmol·g·h for the propane oxidation reaction, which is 4.8 times that of pristine MnO. Meanwhile, a robust hydrothermal stability was guaranteed at 250 °C for 30 h of reaction time. The comprehensive experimental characterizations revealed that the catalytic performance improvement was closely related to the defective structures including the abundant (metal and oxygen) vacancies, distorted crystals, valence imbalance, etc., which prominently weakened the Mn-O bond and stimulated the mobility of surface lattice oxygen, leading to the elevation in the intrinsic oxidation activity. This work exemplifies the significance of defect engineering for the promotion of the oxidation ability of metal oxide, which will be valuable for the further development of efficient non-noble metal catalysts for propane oxidation.
PubMed: 38869532
DOI: 10.3390/nano14110907 -
Optics Express May 2024A spectrometer built using an external cavity pulsed quantum cascade laser is described. The spectrometer has a tuning range from 10 - 13 µm (1,000 - 769 cm) and is...
A spectrometer built using an external cavity pulsed quantum cascade laser is described. The spectrometer has a tuning range from 10 - 13 µm (1,000 - 769 cm) and is designed to target volatile organic compounds (VOCs) which often exhibit water-free molecular absorption within the region. The spectrometer utilizes a hollow silica waveguide gas cell which has an internal volume of a few millilitres, a fast response time (∼1 s), and is advantageous when only low sample volumes, similar to the cell volume, are available. Propane is used as a test gas because it is easy to handle, and its spectral profile is comparable to VOCs of interest. Its absorption in the region is primarily within the ν band which spans from 10.55 - 11.16 µm (948 - 896 cm). Spectral measurements at a range of concentrations show good linearity and an Allan deviation of absorbance values recorded over a 100-minute period indicates a minimum detectable absorbance of 3.5×10 at an integration time of 75 s.
PubMed: 38858996
DOI: 10.1364/OE.521695 -
STAR Protocols Jun 2024A membrane reactor (MR) offers a solution to overcome thermodynamic equilibrium limitations by enabling in situ product separation, enhancing product yields and energy...
A membrane reactor (MR) offers a solution to overcome thermodynamic equilibrium limitations by enabling in situ product separation, enhancing product yields and energy efficiency. Here we present a protocol for synthesizing a carbon MR that couples a H-permeable carbon molecular sieve hollow fiber membrane and a metal supported on zeolite catalyst for non-oxidative propane and ethane dehydrogenation. We describe steps for catalyst preparation, membrane fabrication, and MR construction. The as-developed MR has significant improvements in alkene yield and a record-high stability. For complete details on the use and execution of this protocol, please refer to Liu et al..
PubMed: 38843401
DOI: 10.1016/j.xpro.2024.103112 -
Scientific Reports Jun 2024Volatile light hydrocarbons (VLH) are an essential component of reservoir petroleum fluids. Understanding of their origin and fate is crucial not only in exploration but...
Volatile light hydrocarbons (VLH) are an essential component of reservoir petroleum fluids. Understanding of their origin and fate is crucial not only in exploration but increasingly also in petroleum engineering, as this greatly impacts fluid typing, proper mapping, recoverability and economic value. Due to their sensitivity to subsurface thermal stress and geological alteration processes, their proper characterisation holds promise to understanding the thermal conditions under which petroleum fluids were generated and subsequent fluid modifications during migration and within the reservoir. To study the behaviour of these hydrocarbons under different geological conditions we selected oil and gas fields from two giant conventional petroleum systems in the Arabian Peninsula collectively spanning the entire petroleum spectrum from heavy oil to dry and sour gas. In situ representative bottomhole or recombined pressure-volume-temperature (PVT) fluid composition data were constrained with molecular and stable carbon isotope geochemistry in key wells. Systematic covariance among the slope factor (SF) of propane to pentane and the isomer ratios of butane and pentane with reservoir engineering and geochemical variables in well-constrained black oil to gas condensate petroleum systems allowed the derivation of three formulas to calculate thermal maturity in terms of vitrinite reflectance equivalent from VLH fluid composition: (1) %VRe(SF) = 0.38 SF + 0.41, (2) %VRe(i4) = 1.70 (iC/nC) + 0.61, and (3) %VRe(i5) = 0.89 (iC/nC) + 0.56. The slope factor, iC/nC, and iC/nC ratios all increase monotonically with the thermal evolution of unaltered fluids, allowing for effective application of their derived %VRe formulas across the entire unaltered fluid spectrum, from heavy oil to dry gas. Deviations from indigenous-fluid trends do occur for fluids altered by phase separation, biodegradation, thermal cracking, and thermochemical sulfate reduction (TSR), but corrections can be made to minimize uncertainty in assessing true thermal maturity of altered fluids while respecting other reservoir fluid properties such as gas-to-oil ratio (GOR) and saturation pressure relationships. For instance, although a single charge that has been phase fractionated yields fluids with variable GORs, saturation pressures and slope factors, their butane and pentane isomer ratios remain reflective of the original fluid maturity. In contrast, biodegradation-induced overestimation of maturity based on the isomer ratios of butane and pentane can be corrected by the less affected SF-derived maturity parameter. Reversal to lower apparent SF-derived maturity in thermally and TSR cracked fluids can, on the other hand, be corrected by considering the less affected butane and pentane isomer ratios. Overall, maturities calculated using VLH composition correspond well with fluid type defined based on phase behaviour and source-rock kinetics, thereby putting forward new tools to quantify thermal maturity of reservoir fluids that may be applicable in other petroleum systems.
PubMed: 38830915
DOI: 10.1038/s41598-024-63100-0 -
International Journal of Nanomedicine 2024Messenger RNA (mRNA)-based immunogene therapy holds significant promise as an emerging tumor therapy approach. However, the delivery efficiency of existing mRNA methods...
BACKGROUND
Messenger RNA (mRNA)-based immunogene therapy holds significant promise as an emerging tumor therapy approach. However, the delivery efficiency of existing mRNA methods and their effectiveness in stimulating anti-tumor immune responses require further enhancement. Tumor cell lysates containing tumor-specific antigens and biomarkers can trigger a stronger immune response to tumors. In addition, strategies involving multiple gene therapies offer potential optimization paths for tumor gene treatments.
METHODS
Based on the previously developed ideal mRNA delivery system called DOTAP-mPEG-PCL (DMP), which was formed through the self-assembly of 1.2-dioleoyl-3-trimethylammonium-propane (DOTAP) and methoxypoly (ethylene glycol)-b-poly (ε-caprolactone) (mPEG-PCL), we introduced a fused cell-penetrating peptide (fCPP) into the framework and encapsulated tumor cell lysates to form a novel nanovector, termed CLSV system (CLS: CT26 tumor cell lysate, V: nanovector). This system served a dual purpose of facilitating the delivery of two mRNAs and enhancing tumor immunogene therapy through tumor cell lysates.
RESULTS
The synthesized CLSV system had an average size of 241.17 nm and a potential of 39.53 mV. The CLSV system could not only encapsulate tumor cell lysates, but also deliver two mRNAs to tumor cells simultaneously, with a transfection efficiency of up to 60%. The CLSV system effectively activated the immune system such as dendritic cells to mature and activate, leading to an anti-tumor immune response. By loading Bim-encoded mRNA and IL-23A-encoded mRNA, CLSV/Bim and CLSV/IL-23A complexes were formed, respectively, to further induce apoptosis and anti-tumor immunity. The prepared CLSV/dual-mRNA complex showed significant anti-cancer effects in multiple CT26 mouse models.
CONCLUSION
Our results suggest that the prepared CLSV system is an ideal delivery system for dual-mRNA immunogene therapy.
Topics: Animals; RNA, Messenger; Cell Line, Tumor; Colonic Neoplasms; Genetic Therapy; Immunotherapy; Nanoparticles; Mice; Mice, Inbred BALB C; Cell-Penetrating Peptides; Polyethylene Glycols; Humans; Polyesters; Female; Quaternary Ammonium Compounds; Fatty Acids, Monounsaturated
PubMed: 38828196
DOI: 10.2147/IJN.S452548 -
Journal of Inorganic Biochemistry May 2024Four Pt(II) bis(pyrrole-imine) Schiff base chelates (1-4) were synthesised by previously reported methods, through a condensation reaction, and the novel crystal...
Four Pt(II) bis(pyrrole-imine) Schiff base chelates (1-4) were synthesised by previously reported methods, through a condensation reaction, and the novel crystal structure of 2,2'-{propane-1,3-diylbis[nitrilo(E)methylylidene]}bis(pyrrol-1-ido)platinum(II) (1) was obtained. Pt(II) complexes 1-4 exhibited phosphorescence, with increased luminescence in anaerobic solvents or when bound to human serum albumin (HSA). One of the complexes shows a 15.6-fold increase in quantum yield when bound to HSA and could be used to detect HSA concentrations as low as 5 nM. Pt(II) complexes 1-3 was investigated as potential theranostic agents in MCF-7 breast cancer cells, but only complex 3 exhibited cytotoxicity when irradiated with UV light (λ). Interestingly, the cytotoxicity of complex 1 was unresponsive to UV light irradiation. This indicates that only complex 3 can be considered a potential photosensitising agent.
PubMed: 38805758
DOI: 10.1016/j.jinorgbio.2024.112617 -
Scientific Reports May 2024Different from the Qaidam basin with about 320 billion m microbial gas, only limited microbial gases were found from the Junggar basin with similarly abundant type III...
Different from the Qaidam basin with about 320 billion m microbial gas, only limited microbial gases were found from the Junggar basin with similarly abundant type III kerogen. To determine whether microbial gases have not yet identified, natural gas samples from the Carboniferous to Cretaceous in the Junggar basin have been analyzed for chemical and stable isotope compositions. The results reveal some of the gases from the Mahu sag, Zhongguai, Luliang and Wu-Xia areas in the basin may have mixed with microbial gas leading to straight ethane to butane trends with a "dogleg" light methane in the Chung's plot. Primary microbial gas from degradation of immature sedimentary organic matter is found to occur in the Mahu sag and secondary microbial gas from biodegradation of oils and propane occurred in the Zhongguai, Luliang and Beisantai areas where the associated oils were biodegraded to produce calcites with δC values from + 22.10‰ to + 22.16‰ or propane was biodegraded leading to its C enrichment. Microbial CH in the Mahu sag is most likely to have migrated up from the Lower Wuerhe Formation coal-bearing strata by the end of the Triassic, and secondary microbial gas in Zhongguai and Beisantan uplifts may have generated after the reservoirs were uplifted during the period of the Middle and Late Jurassic. This study suggests widespread distribution of microbial gas and shows the potential to find large microbial gas accumulation in the basin.
Topics: Methane; Natural Gas; Gases; China; Geologic Sediments; Carbon Isotopes
PubMed: 38796638
DOI: 10.1038/s41598-024-62706-8 -
Molecules (Basel, Switzerland) May 2024Noble metals have become a research hotspot for the oxidation of light alkanes due to their low ignition temperature and easy activation of C-H; however, sintering and a...
Noble metals have become a research hotspot for the oxidation of light alkanes due to their low ignition temperature and easy activation of C-H; however, sintering and a high price limit their industrial applications. The preparation of effective and low-noble-metal catalysts still presents profound challenges. Herein, we describe how a Ru@CoMnO spinel catalyst was synthesized via Ru in situ doping to promote the activity of propane oxidation. Ru@CoMnO exhibited much higher catalytic activity than CoMnO, achieving 90% propane conversion at 217 °C. H-TPR, O-TPD, and XPS were used to evaluate the catalyst adsorption/lattice oxygen activity and the adsorption and catalytic oxidation capacity of propane. It could be concluded that Ru promoted synergistic interactions between cobalt and manganese, leading to electron transfer from the highly electronegative Ru to Co and Mn. Compared with CoMnO, 0.1% Ru@CoMnO, with a higher quantity of lattice oxygen and oxygen mobility, possessed a stronger capability of reducibility, which was the main reason for the significant increase in the activity of Ru@CoMnO. In addition, intermediates of the reaction between adsorbed propane and lattice oxygen on the catalyst were monitored by in situ DRIFTS. This work highlights a new strategy for the design of a low-noble-metal catalyst for the efficient oxidation of propane.
PubMed: 38792116
DOI: 10.3390/molecules29102255 -
International Journal of Molecular... May 2024A new, eco-friendly process utilising the green solvent propylene carbonate (PC) has been developed to perform -alkylation of -, - and/or -containing heterocyclic...
A new, eco-friendly process utilising the green solvent propylene carbonate (PC) has been developed to perform -alkylation of -, - and/or -containing heterocyclic compounds. PC in these reactions served as both the reagent and solvent. Importantly, no genotoxic alkyl halides were required. No auxiliary was necessary when using anhydrous PC. Product formation includes nucleophilic substitution with the concomitant loss of water and carbon dioxide. Substrates prepared, including the newly invented PROTAC drugs, are widely used.
Topics: Alkylation; Heterocyclic Compounds; Propane; Solvents; Green Chemistry Technology
PubMed: 38791560
DOI: 10.3390/ijms25105523 -
Nature Communications May 2024By combining the porosity of crystalline metal-organic frameworks (MOFs) with the unique processability of the liquid state, melt-quenched MOF glasses offer exciting...
By combining the porosity of crystalline metal-organic frameworks (MOFs) with the unique processability of the liquid state, melt-quenched MOF glasses offer exciting opportunities for molecular separation. However, progress in this field is limited by two factors. Firstly, only very few MOFs melt at elevated temperatures and transform into stable glasses upon cooling the corresponding MOF liquid. Secondly, the MOF glasses obtained thus far feature only very small porosities and very small pore sizes. Here, we demonstrate solvent-assisted linker exchange (SALE) as a versatile method to prepare highly porous melt-quenched MOF glasses from the canonical ZIF-8. Two additional organic linkers are incorporated into the non-meltable ZIF-8, yielding high-entropy, linker-exchanged ZIF-8 derivatives undergoing crystal-to-liquid-to-glass phase transitions by thermal treatment. The ZIF-8 glasses demonstrate specific pore volumes of about 0.2 cmg, adsorb large amounts of technologically relevant C and C hydrocarbons, and feature high kinetic sorption selectivities for the separation of propylene from propane.
PubMed: 38789474
DOI: 10.1038/s41467-024-48703-5