Metal-Organic Frameworks (MOFs) Based Nano-Materials in the Applications as Sensors and Catalysts

This dissertation begins with an introduction into the development of MOFs, particularly nano-sized MOFs and MOFs based metal nano-particles. (Chapter I) The reported synthetic strategies as well as their application in bio-related and catalyst field are discussed and perspectives on the promising future direction of this field are also presented. Chapter II demonstrates that “turn-on” fluorescent sensors can be assembled by combining a fluorophore and a recognition moiety within a complex cavity of a multicomponent MOF. The selective binding of CN- to recognition moieties inhibited the energy transfer between the two moieties, resulting in a fluorescence “turn on” effect. The optimized MOF-sensor had a CN- detection limit of 0.05 µM, which is much lower than traditional CN- molecular fluorescent sensors (~0.2 µM). Chapter III demonstrates that aggregation caused quenching of perylenes can be minimalized by molecular incorporation into metal-organic frameworks (MOFs). The average distance between perylene moieties was tuned by changing the linker ratios, thus controlling the fluorescence intensity, emission wavelength, and quantum yield. Taking advantage of the tunable fluorescence, inherent porosity, and high chemical stability of the parent MOF, utilization of the framework was able to be applied as a fluorescent sensor for oxygen detection in the gas phase. Ultimately, this work showed fast response times and good recyclability of the material. Chapter IV demonstrates that the utility of a coordination cage as a nanoparticle container to encapsulate ruthenium nanoparticles and tune their crystalline structures. Using this method, a rare fcc crystalline structure was able to be formed. This nanoparticle-cage composite exhibited record-high catalytic activity toward ammonia borane dehydrogenation. In addition, it provided a strategy for the encapsulation of metal nanocrystals within a soluble molecular cage, forming homogeneous catalysts with unprecedented activity. The main purpose of the work presented in this dissertation is to (1) explore the application of MOFs in the field of fluorescence sensors; (2) establish synthetic strategies for nano-sized MOFs; and (3) improve the catalytically performance of PCC supported metal nanoparticles. Building up on this work and the rapid development by others in this field, promising applications of MOFs in fluorescence sensors, bio-sensing, and clean energy generation are anticipated

Mechanism of inflammatory cancer-associated fibroblast-mediated drug resistance in colorectal cancer cells

Background and purpose: Colorectal cancer (CRC) is one of the common malignancies, but the mechanism by which it develops resistance to drug remains unclear. The tumor microenvironment (TME), especially cancer-associated fibroblast (CAF), plays an important role in the occurrence, development and drug resistance of tumors. This study aimed to investigate the effect of inflammatory cancer-associated fibroblasts (iCAF) on drug resistance in CRC cells and its possible mechanism. Methods: The primary CAFs were collected from CRC patients underwent surgery in Putuo Hospital, Shanghai University of Traditional Chinese Medicine from Aug. 2022 to Sep. 2022, and the primary cells were sorted according to the surface marker of CAF[approved by the Ethics Committee of Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine: PTEC-A-2023-5(S)-1], platelet derived growth factor receptor alpha (PDGFRA), to screen iCAF. Human intestinal fibroblast (HIF) and iCAF cells were cultured using serum-free medium to obtain conditioned medium. According to the treatment method, colon cancer cells were divided into control group (no treatment), experimental group 1(treated with HIF-CM) and experimental group 2 (treated with iCAF-CM). We observed the changes in the survival rate and apoptotic rate of CRC cells, the changes in protein and mRNA levels and the effect on the Wnt/β-catenin signaling pathway after stimulation with HIF-CM or iCAF-CM. Results: After iCAFs stimulation, the half inhibition concentration (IC50) of CRC cells was higher compared with the control group and HIF-CM group (P<0.05). Compared with the control group and HIF-CM group, the apoptotic rate of tumor cells in iCAF-CM group decreased significantly, the expression of caspase-3 was decreased, and the expressions of Bcl-2, Bcl-xL and survivin were increased (P<0.05). The Wnt/β-catenin signaling pathway was activated in the iCAF-CM group. Conclusion: iCAFs can mediate drug resistance in CRC cells, and the mechanism is related to the activation of Wnt/β-catenin signaling pathway

Metal 3D-printing for repair of steel structures

This work employs an innovative technique, wire arc additive manufacturing (WAAM) which is a type of directed energy deposition, for fatigue strengthening of cracked steel components. Different steel plates with a central crack were tested under high-cycle fatigue loading regime, including a reference plate, a plate repaired by WAAM with as-deposited profile, and a plate repaired by WAAM and subsequently machined to reduce stress concentration factors. Corresponding finite element simulation was conducted to provide a better understanding on the mechanism of WAAM-repair. The existing central crack in the reference plate propagated and led to a rupture after 0.94 million cycles, while those in the two WAAM-repaired plates did not propagate, due to the increased net cross-section and the compressive stresses induced by the depositing process. However, in the second plate, a new crack initiated at the root of WAAM profile as a result of local stress concentration, and the fatigue life reached 2.2 million cycles (2.3 times as the reference plate). The third plate, on the other hand, survived more than 9 million fatigue cycles with no visible degradation, thanks to its smooth machined profile. The findings of this work indicate that WAAM repair shows great potential as a technique to address fatigue-related damages in steel structures

Fully endoscopic transforaminal discectomy for thoracolumbar junction disc herniation with or without calcification under general anesthesia: Technical notes and preliminary outcomes

ObjectiveTo evaluate the feasibility, safety, and outcomes of percutaneous endoscopic transforaminal discectomy (PETD) for thoracolumbar junction disc herniation (TLDH) with or without calcification.MethodsThis study included 12 patients diagnosed with TLDH with or without calcification who met the inclusion criteria and underwent surgery for PETD from January 2019 to December 2021. The mean patient age, operation time, hospitalization time, time in bed, and complications were recorded. Patients were followed up for at least 9 months. Visual analog scale (VAS) scores for low-back and leg or thoracic radicular pain and modified Japanese Orthopedic Association score (m-JOA) scores were preoperatively evaluated, at 1 day and 3, 6, and 12 months postoperatively or at last follow-up. The modified MacNab criteria were used to evaluate clinical efficacy at 12 months postoperatively or at last follow-up.ResultsThe mean patient age, operation time, hospitalization time, and time in bed were 53 ± 13.9 years, 101.3 ± 9.2 min, 4.5 ± 1.3 days, and 18.0 ± 7.0 h, respectively. The mean VAS scores of low-back and leg or thoracic radicular pain improved from 5.8 ± 1.5 and 6.5 ± 1.4 to 2.0 ± 0.9 and 1.3 ± 0.5, respectively (P < 0.05). The m-JOA score improved from 7.5 ± 1.2 to 10.0 ± 0.7 (P < 0.05). The overall excellent–good rate of the modified MacNab criteria was 83.3%. No severe complications occurred.ConclusionFully endoscopic transforaminal discectomy and ventral decompression under general anesthesia is a safe, feasible, effective, and minimally invasive method for treating herniated discs with or without calcification at thoracolumbar junction zone

Differential Regulation of H3K9/H3K14 Acetylation by Small Molecules Drives Neuron-Fate-Induction of Glioma Cell

Differentiation therapy using small molecules is a promising strategy for improving the prognosis of glioblastoma (GBM). Histone acetylation plays an important role in cell fate determination. Nevertheless, whether histone acetylation in specific sites determines GBM cells fate remains to be explored. Through screening from a 349 small molecule-library, we identified that histone deacetylase inhibitor (HDACi) MS-275 synergized with 8-CPT-cAMP was able to transdifferentiate U87MG GBM cells into neuron-like cells, which were characterized by cell cycle arrest, rich neuron biomarkers, and typical neuron electrophysiology. Intriguingly, acetylation tags of histone 3 at lysine 9 (H3K9ac) were decreased in the promoter of multiple oncogenes and cell cycle genes, while ones of H3K9ac and histone 3 at lysine 14 (H3K14ac) were increased in the promoter of neuron-specific genes. We then compiled a list of genes controlled by H3K9ac and H3K14ac, and proved that it is a good predictive power for pathologic grading and survival prediction. Moreover, cAMP agonist combined with HDACi also induced glioma stem cells (GSCs) to differentiate into neuron-like cells through the regulation of H3K9ac/K14ac, indicating that combined induction has the potential for recurrence-preventive application. Furthermore, the combination of cAMP activator plus HDACi significantly repressed the tumor growth in a subcutaneous GSC-derived tumor model, and temozolomide cooperated with the differentiation-inducing combination to prolong the survival in an orthotopic GSC-derived tumor model. These findings highlight epigenetic reprogramming through H3K9ac and H3K14ac as a novel approach for driving neuron-fate-induction of GBM cells

The Impact of Government Intervention and Cap-and-Trade on Green Innovation in Supply Chains: A Social Welfare Perspective

This paper discusses the impact of government intervention (greenness threshold limit) and cap-and-trade policy on green investment, stakeholder profits and social welfare under different power structure scenarios in the green supply chain. First, a two-level green supply chain system is constructed: a manufacturer that produces green products and complies with cap-and-trade policies and a retailer that sells green products. Based on the Stackelberg game and Cournot game, we compare the optimal solutions under the government intervention mechanism and cap-and-trade mechanism with manufacturer leadership, retailer leadership and equal power. The results are as follows: (1) both government intervention and the cap-and-trade mechanism are conducive to an increase in green technology innovation and profit, but excessive control will lead to a decline in social welfare. (2) The results in the concentrated scenario were better than those in the dispersed scenario. In the decentralized state, the result of equal power is the best, the result of retailer leadership is next, and the result of manufacturer leadership is the worst. (3) The lower cost of green investment will cause enterprises to give up purchasing carbon emission permits from the carbon market

Achieving material diversity in wire arc additive manufacturing: Leaping from alloys to composites via wire innovation

Multi-material components featuring high performance and design flexibility have attracted considerable attention, providing solutions to meet the performance demands of high-end equipment components. Achieving material diversity in additive manufacturing (AM) is a fundamental step towards manufacturing multi-material components. Wire arc additive manufacturing (WAAM), an important branch of AM technology, boasts notable advantages in the efficient and customized preparation of large-scale parts due to its high deposition efficiency and unrestricted forming size. However, achieving material diversity in WAAM, constrained by its reliance on wire-form raw materials, has emerged as a compelling challenge. Wire innovation, including multiple, stranded, and cored wires, have furnished solutions to this challenge. To this end, this review provides an overview of the current developments in WAAM via wire innovation and suggests future research directions, aiming to serve as a reference for the further advancement of WAAM. Initially, the article introduces several WAAM printing forms, their manufacturing features, printable materials and inherent manufacturing limitations, and the intermixing of metal constituents of WAAM, prior to highlighting the advantages and necessity of achieving material diversity. Subsequently, the exposition of multi-wire-arc AM demonstrates its utility in the preparation of binary or ternary alloys, inclusive of intermetallic compounds and functionally graded materials, responding adeptly to the deficiencies of conventional WAAM, which is limited to single-material printing. The merits and progression of stranded-wire-arc AM for high-entropy alloy production are synthesized and debated, especially given that creating components with multiple metal elements via multi-wire-arc AM customarily confronts the constraint of necessitating more intricate manufacturing equipment and processes. Further, the review explores the recently developed cored-wire-arc AM technology, which actualizes the manufacturing of composite materials, amalgamating metals and non-metals, to remedy the issues encountered with standard WAAM, incapable of realizing non-metallic material printing. Considering machine tools as an important means to achieve material diversity in WAAM, we expand on the current machine tool architecture and its corresponding design tools. Finally, the current research status on WAAM via wire innovation is summarized and potential future research directions are proposed

Effects of Carbon Policy on Carbon Emission Reduction in Supply Chain under Uncertain Demand

Although there are many articles on carbon emission reduction of sustainable supply chain, most of them study the carbon emission reduction efficiency of supply chain in the case of single carbon policy or demand determination. Based on previous studies, this paper considered a supply chain consisting of a single manufacturer and a single retailer in an uncertain demand market. The effects of demand randomness and different carbon policies on carbon emission reduction level and optimal decision in supply chain were studied by constructing mean-variance utility function and Stackelberg game. Due to the difficulty of data acquisition, this paper verified the equalization results by numerical simulation. The results show that: (1) cap-and-trade policy, government subsidy policy and carbon tax policy can promote the carbon emission reduction investment of supply chain, while carbon tax policy will lead to the decline of the overall profit of supply chain; (2) For the manufacturer and the retailer, adopting a strategy with a low degree of risk avoidance will increase its own profits; (3) For the supply chain as a whole, it is more advantageous for manufacturers to adopt higher risk avoidance strategies, while retailers to adopt lower risk avoidance strategies. In addition, in the conclusion, this paper puts forward management implications related to stakeholders, thus providing help for the development of sustainable supply chain