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A comprehensive economic analysis of twenty light olefin production pathways has been performed, covering current and promising processes from fossil (petroleum, coal and natural gas) and renewable resources (biomass and CO2). Taking steam cracking of naphtha as the benchmark, this study gives an economic perspective and points out the bottleneck in different olefin production pathways. The assessment indicates that nearly all renewable pathways are economically unattractive currently and the raw material cost accounts for dominant contribution in most pathways, especially in the oil-, natural gas- and CO2-derived pathways. For the ways of methanol-to-olefins and methanol-to-propylene, fossil pathways are cost-competitive according to the date of current Chinese market prices. However, the price of feedstock hydrogen needs to be lowered by 55% to fill the cost gap between CO2-derived pathways and the benchmark. For the ways of oxidative coupling of methane and Fischer-Tropsch synthesis to olefins, fossil pathways enable cost-competitive processes by feedstock price fall, but further process improvement is required to approach benchmark in renewable pathways. Conditionally, a decrease in ethanol price by 45% can make ethanol dehydration pathway profitable. In addition, costs can reduce by 4%–23% in different pathways as the production scales expand from 100 to 1000 kt/a, resulting in a change from high cost to economic profit for some of the pathways. The results quantify the need for improvements on feedstock price, scale size and process improvement to achieve competitive production costs.

Exploiting advantages of a double–type support to create an active site–isolated heterobifunctional catalyst is beneficial to an efficiently sequential organic transformation. Herein, an integrated soluble polymer and mesoporous silica as a double–type support to immobilize the tertiary amine–Ru/diamine–bifunctionality for the construction of an active site–isolated catalyst is developed, where the tertiary amine–functionality is tethered in the outer soluble polymer and chiral ruthenium/diamine–functionality is anchored within the inner mesoporous silica. Electron microscopy images, together with analyses of solid–state NMR spectra, disclose that catalyst possesses the uniformly distributive morphology with well–defined single–site ruthenium/diamine active centers. As envisaged, the heterobifunctional catalyst performs a highly efficient aza–Michael addition/asymmetric transfer hydrogenation enantioselective cascade reaction, where the outer tertiary amine–functionality enables a high reactivity to afford β–secondary amino ketones via an aza–Michael addition reaction of enones and amines, and the inner chiral ruthenium/diamine–functionality guarantees a high enantioselectivity to chiral γ–secondary amino alcohols via an asymmetric transfer hydrogenation of β–secondary amino ketones. Furthermore, this catalyst can also be recovered easily and recycled for six runs, showing a practical preparation of aryl–substituted γ–secondary amino alcohols.

Hydrogel coating has been attractive to improve titanium implants’ compatibility with biological surroundings and their performance in clinic. Herein, a CaCO3 layer is fabricated at the interface of hydrogel–titanium to achieve strong interfacial bonding. This strategy does not require complicated surface modifications and has good prospects in the field of biomedical applications.

Lignin is a renewable and abundant aromatic polymer found in plants. We herein propose a “cutting tail” methodology to produce phenol from lignin, which is achieved by combining Ru/CeO2 catalyst and CuCl2 oxidant via an oxidation–hydrogenation route. Phenol was obtained from separated poplar lignin with 13 wt % yield. Even raw biomass, such as poplar, birch, pine, peanut, bamboo willow, and straw, could be converted into phenol in 1–33 mg per gram of biomass.

Valuable polyester monomers and plasticizers-1,4-cyclohexanedimethanol (CHDM), 1,4-cyclohexanedicarboxylic acid (CHDA), and 1,2-cyclohexanedicarboxylates-have been prepared by a new strategy. The synthetic processes involve a proline-catalyzed formal [3+1+2] cycloaddition of formaldehyde, crotonaldehyde, and acrylate (or fumarate). CHDM is produced after a subsequent hydrogenation step over a commercially available Cu/Zn/Al catalyst and a one-pot hydrogenation/oxidation/hydrolysis process yields CHDA, whereas 1,2-cyclohexanedicarboxylate is obtained by a Pd/C-catalyzed tandem decarbonylation/hydrogenation step.

Biomass is renewable and the most abundant carbon resource, and it shows great potential for sustainable production of chemicals in the future. With respect to limited fossil reserves, biomass conv...

Biomass chemical industry potentially reduces fossil energy dependence and addresses climate change, however, reaching technical feasibility and economic competitiveness are still crucial challenges, especially in the conversion of lignocellulosic biomass. Herein, an early-stage analysis is conducted to evaluate technical, economic, and environmental benefits of ethylene glycol (EG) production from lignocellulose, which, for one representative demonstration, provides an insight into opportunities and constraints associating with the transition from lab testing to practical industrialization of biochemicals. With process design and modeling, techno-economic analysis, and life cycle assessment, the results reveal that lignocellulosic biomass-derived EG (bio-EG) is at present attractive in aspects of life cycle primary fossil energy depletion and greenhouse gas emissions, but the total production cost of bio-EG is 43% and 20% higher than that of coal-EG and petro-EG. To achieve the economic benefits of bio-EG, research strategies, such as raising the product yield, changing hydrogen sources, increasing feedstock collection efficiency, and lowing water consumption were explored and proved to be effective measures. In addition, a carbon tax of 184 and 598 CNY·t−1 CO2eq are the breakeven points to reach economic benefits of bio-EG compared to petro-EG and coal-EG, respectively. This work aims at conducting a comprehensive evaluation of bio-EG to promote its practical application, and also shedding light on bright prospects and general approaches to develop lignocellulosic biochemicals.

Human hair keratin (HHK) is successfully exploited as raw materials for 3D scaffolds for soft tissue regeneration owing to its excellent biocompatibility and bioactivity. However, most HHK scaffolds are not able to achieve the anisotropic mechanical properties of soft tissues such as tendons and ligaments due to lack of tunable, well-defined microstructures. In this study, directed ice templating method is used to fabricate anisotropic HHK scaffolds that are characterized by aligned pores (channels) in between keratin layers in the longitudinal plane. In contrast, pores in the transverse plane maintain a homogenous rounded morphology. Channel widths throughout the scaffolds range from ≈5 to ≈15 µm and are tunable by varying the freezing temperature. In comparison with HHK scaffolds with random, isotropic pore structures, the tensile strength of anisotropic HHK scaffolds is enhanced significantly by up to fourfolds (≈200 to ≈800 kPa) when the tensile load is applied in the direction parallel to the aligned pores. In vitro results demonstrate that the anisotropic HHK scaffolds are able to support human dermal fibroblast adhesion, spreading, and proliferation. The findings suggest that HHK scaffolds with well-defined, aligned microstructure hold promise as templates for soft tissues regeneration by mimicking their anisotropic properties. Agency for Science, Technology and Research (A*STAR) Accepted version This research is supported by the Agency for Science, Technology and Research (A*STAR) under its Acne and Sebaceous Gland Program & Wound Care Innovation for the Tropics IAF-PP (H17/01/a0/008 & H17/01/a0/0L9).

Human hair keratins (HHK) are known for their biocompatibility and potential to regulate cell response, possibly due to the presence of the leucine-aspartic-valine cell adhesion and signaling motifs. Together with the abundance of cysteine residues in HHK, 3D HHK scaffolds are fabricated through cryogelation based on spontaneous disulfide crosslinks and noncovalent interactions. Herein, the molecular mechanism of HHK self-assembly during cryogelation is interrogated and the influence of cryogelation parameters on the properties of the resultant scaffolds is studied. With successive freeze-thaw cycles, the storage modulus (G') of HHK cryogels substantially improves from 116.4 Pa at freeze-thaw cycle 3 (FT3) to 1908.7 Pa at freeze-thaw cycle 10 (FT10). Meanwhile, it is found that complete thiol-capping of HHK samples significantly inhibits cryogel formation as compared to partially or uncapped HHK samples, suggesting the dominant role of disulfide stabilization in cryogelation. Finally, uniaxial compression tests on HHK sponges demonstrate that FT cycling, from 0 to 10, is able to improve the compression modulus of sponges by ≈12-folds. These findings show that macroscale properties of HHK cryogels can be conveniently modulated by physical parameters of cryogelation and that disulfide bonding is the main stabilizing force in HHK cryogels. Agency for Science, Technology and Research (A*STAR) Accepted version This research is supported by the Agency for Science, Technology and Research (A*STAR) under its Wound Care Innovation for the Tropics IAF-PP (H17/01/a0/0L9). The authors would like to acknowledge the Facility for Analysis, Characterization, Testing and Simulation, Nanyang Technological University, Singapore, for their technical support in scanning electron microscopy analysis.

Ingestion of engineered nanomaterials (ENMs) is inevitable due to their widespread utilization in the agrifood industry. Safety evaluation has become pivotal to identify the consequences on human health of exposure to these ingested ENMs. Much of the current understanding of nanotoxicology in the gastrointestinal tract (GIT) is derived from studies utilizing pristine ENMs. In reality, agrifood ENMs interact with their microenvironment, and undergo multiple physicochemical transformations, such as aggregation/agglomeration, dissolution, speciation change, and surface characteristics alteration, across their life cycle from synthesis to consumption. This work sieves out the implications of ENM transformations on their behavior, stability, and reactivity in food and product matrices and through the GIT, in relation to measured toxicological profiles. In particular, a strong emphasis is given to understand the mechanisms through which these transformations can affect ENM induced gut nanotoxicity. Nanyang Technological University Accepted version Nanyang Technological University—Harvard School of Public Health Initiative for Sustainable Nanotechnology (NTU‐Harvard SusNano).

In the analysis and processing of image recognition, extracting useful and valuable data from the original dataset has become a problem. Since the data to be processed often presents high dimensional and nonlinear feature, reasonable dimensionality reduction is an necessary method for improving the accuracy of data analysis. One of the dimensionality reduction methods Kernel Principal Component Analysis (KPCA) has certain advantages in dealing with nonlinear data, but it also has defects when facing the dataset in which data owe highly complex relationship. The other linear dimensional reduction method Linear Discriminant Analysis (LDA) has supervisory characteristics, which can reduce the dimensionality of dataset in which data owe highly complex relationship. However it can only handle linear data. So we propose a hybrid method which is the combination of the above two methods called KPCA-LDA. By it the new dataset obtained by the step of dimensionality reduction is beneficial to be processed in next step for classification. We combine KPCA-LDA with the Back Propagation Neural Network (BPNN) method to achieve the classification of handwritten numbers. The experimental results show that the classification accuracy of the proposed KPCA-LDA-BPNN model can reach 98.67%, which is about 3%-5% higher than the original method using K Nearest Neighbor (KNN) and Support Vector Machine (SVM).

Quinazolinones, an important class of heterocyclic compounds, have been widely used in pharmaceuticals because of their biological activity. However, the efficient and economical synthesis of quinazolinones has remained a challenge. A novel synthetic approach has now been developed to produce quinazolinones from olefins, CO, and amines over heterogeneous Ru-clusters/ceria catalyst in the absence of acids, bases, and oxidants. Furthermore, H2 O is generated as the only by-product. A series of quinazolinones with aromatic or non-aromatic substituents can be obtained in yields of up to 99 %. The Ru-clusters/ceria can be reused at least four times. The analysis of the E-factor (environmental impact factor) for the synthesis of 2-ethyl quinazolinone suggests that this system is more environmentally friendly than other processes reported previously.

Over exposure of UV light could cause serious damages to human being, such as DNA damage, skin aging and cancer, cataract and so on. Hence, there is an urgent need to develop optically transparent materials as windows, glasses and protection film etc. to filter UV light. In the present study, a homogeneous polyvinyl alcohol (PVA)/zinc oxide (ZnO) film was fabricated via a facile in situ method by controlling the reaction of Zn2+ with OH- ions and the dehydration process of Zn(OH)42- throughout PVA hydrogel matrix. The obtained PVA/ZnO film can absorb over 99% of UV light at wavelength region between 200 and 350 nm, and its optical transparency in the visible region was similar to that of neat PVA film (87–90%). In addition, this hybrid film was flexible (~5% strain at fracture) with excellent tensile strength (130–140 MPa), and able to be easily modulated onto various substrates as UV-protection film. Overall, this facile, low cost in situ fabrication method with environment-friendly nature could be applicable to various hydrogel systems for developing novel transparent UV-shielding nanocomposites with desired properties.

Ideal bone scaffolds having good biocompatibility, good biodegradability, and beneficial mechanical properties are the basis for bone tissue engineering. Specifically, cell migration within 3D scaffolds is crucial for bone regeneration of critical size defects. In this research, hydroxyapatite scaffolds with three different types of architectures (tortuous, parallel, and graded channels) are fabricated using the freeze-casting (ice-templating) method. While most studies promote cell migration by chemical factors, it can be greatly enhanced by introducing only graded channels as compared with tortuous or parallel channels. The results provide insights and guidance in designing novel scaffolds to enhance cell migration behavior for bone tissue regeneration.

Although it is widely acknowledged that ionic substitutions on bulk hydroxyapatite substrates have a strong impact on their biological performance, little is known of their effect on nanoparticles (NPs) especially when used for gene transfection or drug delivery. The fact that NPs would be internalized poses many questions but also opens up many new possibilities. The objective of the present work is to synthesize and assess the effect of a series of hydroxyapatite-like (HA) NPs doped with various ions on cell behavior, i.e. carbonate, magnesium and co-addition. We synthesized NPs under similar conditions to allow comparison of results and different aspects in addition to assessing the effect of the doping ion(s) were investigated: (1) the effect of performing the cell culture study on citrate-dispersed NPs and on agglomerated NPs, (2) the effect of adding/excluding 10% of foetal bovine serum (FBS) in the cell culture media and (3) the type of cell, i.e. MG-63 versus rat mesenchymal stem cells (rMSCs). The results clearly demonstrated that Mg-doping had a major effect on MG-63 cells with high cytotoxicity but not to rMSCs. This was a very important finding because it proved that doping could be a tool to modify NP internalization. The results also suggest that NP surface charge had a large impact on MG-63 cells and prevents their internalization if it is too negative—this effect was less critical for rMSCs