Deconvolution of single-cell multi-omics layers reveals regulatory heterogeneity

Heterogeneity in gene expression and epigenetic states exists across individual cells. Here, the authors develop scCAT-seq, a technique for simultaneously performing ATAC-seq and RNA-seq within the same single cell

Zeolite with tunable intracrystal mesoporosity synthesized with carbon aerogel as a secondary template

In this paper, carbon aerogel was investigated as a potential template for generating size controllable intracrystal mesopore system in zeolite. For this purpose zeolite samples were synthesized with carbon aerogels having different structural parameters as secondary template, and characterized with XRD, FT-IR, SEM, TEM as well as low-temperature nitrogen adsorption. Results indicated that the carbon aerogel synthesized by simple ambient drying method can be used for generating additional intracrystal mesopore channel in zeolite without special control on the crystallization conditions. The pore size of the additional intracrystal mesopore system in zeolite can be controlled over a wide range by simply changing the catalyst concentration during sol-gel reaction of resorcinol and formaldehyde, the initial step of carbon aerogel synthesis. (C) 2008 Elsevier Inc. All rights reserved

Method of Selecting Active Parameters Using Sensitivity Analysis and Linear Programming

It is necessary to select appropriate active parameters to ensure both the accuracy and computation efficiency before the global analysis of chemical kinetic model. This paper proposes a new method for selecting the active parameters on the base of the combination of sensitivity analysis and linear programming. Compared with the usual methods for selecting active parameters, such as the local sensitive analysis, the characteristics of the proposed method is preliminary visualization of the possible influence of the selected active parameters on the model outputs in the process of parameter selection, ensuring the reliability of the selected active parameters. Considering the computation efficiency, the number of selected active parameters can be controlled in a suitable size through combining with dichotomy or other screening techniques. In the study, the pre-exponential factors of the Arrhenius equations in the USC-Mech II model were considered as the candidate parameters and the uncertainties of the pre-exponential factors were set. Taking the ignition of ethylene for example, the 10 reactions that can increase the ignition time of ethylene under a wide range of conditions with equivalence ratio of 1, 0.1 similar to 1 MPa and 1000 K similar to 1500 K were successfully selected using the proposed method. Then, the 10 active parameters were tested in each condition. The results showed that the selected active parameters can make the ignition delay time close to the target for each condition, which reflects the reliability of active parameter selection

Purification of artemisinin precursor amorphadiene from microbial metabolites containing isomeride farnesene: Solid-Pd chemocatalysis of farnesene to squalene with high boiling point

Due to complex chemical mechanism of sesquiterpene synthases, amorpha-4, 11-diene (AD) from microbial fermentation contained isomeride β-farnesene (FA) with similar boiling point. For purifying AD, FA was converted to biofuel-valued squalene (SQ) with high boiling point using solid Pd catalysts. (NHT)OS-Pd catalysts resulted in FA conversion of >99.9% and SQ selectivity of >99.0% at 80 °C for 5 h. Moreover, this catalyst exhibited great stability and recycling performance. When (NHT)OS-Pd was applied to AD mixture, almost FA was converted to SQ and AD remained in the pre-reaction state. As SQ had a higher boiling point, AD was easily distilled out

Integrating Fermentation Engineering and Organopalladium Chemocatalysis for the Production of Squalene from Biomass-Derived Carbohydrates as the Starting Material

The transition from fossil resources to renewable biomass for the production of valuable chemicals and biobased fuels is a crucial step towards carbon neutrality. Squalene, a valuable chemical extensively used in the energy, healthcare, and pharmaceutical fields, has traditionally been isolated from the liver oils of deep-sea sharks and plant seed oils. In this study, a biochemical synergistic conversion strategy was designed and realized to convert glucose to squalene by combining fermentation technology in yeast with reductive coupling treatment of dienes. First, glucose derived from hydrolysis of cellulose was used as a renewable resource, using genetically engineered Saccharomyces cerevisiae as the initial biocatalyst to produce β-farnesene with a titer of 27.6 g/L in a 2.5 L bioreactor. Subsequently, intermediate β-farnesene was successfully converted to squalene through the organopalladium-catalyzed reductive coupling reaction involving the formation of Pd(0)L2 species. Under mild reaction conditions, impressive β-farnesene conversion (99%) and squalene selectivity (100%) were achieved over the Pd(acac)2 catalyst at a temperature of 75 °C in an ethanol solvent after 5 h. This advancement may provide insights into broadening squalene production channels and accessing the complex skeletons of natural terpenoids from biorenewable carbon sources, offering practical significance and economic benefits

Method of Selecting Active Parameters Using Sensitivity Analysis and Linear Programming

It is necessary to select appropriate active parameters to ensure both the accuracy and computation efficiency before the global analysis of chemical kinetic model. This paper proposes a new method for selecting the active parameters on the base of the combination of sensitivity analysis and linear programming. Compared with the usual methods for selecting active parameters, such as the local sensitive analysis, the characteristics of the proposed method is preliminary visualization of the possible influence of the selected active parameters on the model outputs in the process of parameter selection, ensuring the reliability of the selected active parameters. Considering the computation efficiency, the number of selected active parameters can be controlled in a suitable size through combining with dichotomy or other screening techniques. In the study, the pre-exponential factors of the Arrhenius equations in the USC-Mech II model were considered as the candidate parameters and the uncertainties of the pre-exponential factors were set. Taking the ignition of ethylene for example, the 10 reactions that can increase the ignition time of ethylene under a wide range of conditions with equivalence ratio of 1, 0.1 similar to 1 MPa and 1000 K similar to 1500 K were successfully selected using the proposed method. Then, the 10 active parameters were tested in each condition. The results showed that the selected active parameters can make the ignition delay time close to the target for each condition, which reflects the reliability of active parameter selection

Coprocessing of Catalytic-Pyrolysis-Derived Bio-Oil with VGO in a Pilot-Scale FCC Riser

A catalytic-pyrolysis-derived bio-oil, which was characterized by higher H/C_eff ratio and lower oxygen content in comparison to fast-pyrolysis-derived bio-oil, was coprocessed with VGO in a pilot-scale FCC riser. The addition of the bio-oil up to 10 wt % gave nearly equivalent oxygenate content and also similar selectivities of gasoline, bottom oil, and coke compared to those in VGO catalytic cracking alone, suggesting the catalytic-pyrolysis-derived bio-oil was a suitable feedstock for FCC coprocessing. However, the dry gas, including hydrogen and light alkane, was significantly decreased in the coprocessing experiment mainly because of the hydrogen transfer between bio-oil and VGO. Radiocarbon analysis of the product showed that 7% carbon of gasoline was derived from the bio-oil when 10 wt % bio-oil was added to VGO. The coprocessing of biomass catalytic pyrolysis and FCC was highly promising for biomass conversion into biofuel

Bridge Responses Induced by Adjacent Subway Station Construction Using Shallow Tunneling Method

This paper presents a case of subway station construction under an existing prestressed concrete bridge with a three-span continuous beam located at the intersection of the 3rd Ring Road, Beijing. The Huayuan Subway Station of line 6, constructed crossing between #7 and the #8 piers of the bridge by the shallow tunneling method, is approximately perpendicular to the existing Huayuan Bridge. The minimum horizontal distance between the pile foundation and the subway station is only 0.08 m. The “Pile-Beam-Arc” construction sequence was used to ensure the safety of both the subway station and the bridge. Moreover, a series of reinforcement measures were adopted to safeguard the project, including deep grouting reinforcement surrounding the pile foundation from ground surface, temporary inverted arch in the middle of No. 5 drift, and the lateral steel support. Even though some cracks were observed on the bridge deck surface by the on-site deformation monitoring, the results were still within the proposed control standard. To prevent the further development of the cracks, jacking protection measure and bonded steel constructed under the box girder were performed. The related measures proposed in this research can provide useful references for future similar projects

Lignin Pyrolysis and in Situ Hydrodeoxygenation over MoO₃: Interaction between MoO₃ and Lignin

Lignin pyrolyses and in situ hydrodeoxygenation over MoO₃ with varying lignin/MoO₃ mass ratios (L/M) at different temperatures were studied in a free-falling reactor. The presence of MoO₃ not only facilitated the depolymerization of lignin to liquid and gas products but also catalyzed the in situ hydrodeoxygenation of the resulting liquid product to phenol, both of which were further intensified with the increases of temperature and the MoO₃ amount. Negative apparent solid yield and over 100% apparent gas yield were obtained in some cases because of the reaction of MoO₃ during lignin pyrolysis. To clarify this phenomenon, detailed TG/MS, XRD, and XPS investigations on spent MoO₃ were carried out. The results indicate that Mo⁶⁺ was partly reduced to Mo⁴⁺ and Mo⁵⁺ during the lignin pyrolysis, mainly caused by the reaction with carbon from lignin rather than hydrogen from carrier gas