Unveiling the thermolysis natures of ZIF-8 and ZIF-67 by employing in situ structural characterization studies

The thermolysis routes of two isostructural metal–organic framework compounds (Zn-based ZIF-8 and Co-based ZIF-67) are investigated based on temperature-dependent and time-dependent in situ Fourier transform infrared (FTIR) spectroscopy and in situ X-ray diffraction data, as well as thermogravimetric-differential scanning calorimetry (TG-DSC) analyses and density functional theory (DFT) calculations. These data highlight thermolysis effects on different vibrations and dissociations within specific atomic moieties. The coordination differences between Zn–N and Co–N lead to the distinct thermolysis routes of ZIF-8 and ZIF-67. ZIF-8 is easily deformed during heating while decomposes at a higher temperature due to the saturated Zn–N coordination. ZIF-67, however, does not deform during heating due to the stronger Co–N bonds, but easily reacts with oxygen due to the unsaturated Co–N bonds. Our results demonstrate that in situ FTIR paired with in situ XRD is a powerful technique for MOF thermolysis investigation, and we suggest that the thermolysis mechanisms of MOFs may be unveiled by investigating a series of MOFs having different coordination types using in situ characterisation methods

From semisolid metal processing to thixotropic 3D printing of metallic alloys

Semisolid metal processing is a well-known technology that can be used to enhance manufacturing product quality in broad industries. The technology controls the thixotropic properties of alloys within their solidus and liquidus temperature ranges. In general, most known alloys can generate semisolid slurries at high solid fractions, and the remaining can form slurries at low solid fractions. This has provided opportunities for many metals and alloys to be processed as semisolid slurries in today’s casting industry. However, only a few researchers studied this technology potentially for a new metal-based additive manufacturing or 3D printing process. This article reviewed literature and findings from thixotropy rheology and semisolid metal processing methods, finally to thixotropic metal 3D printing. The survey shows that more future work is needed, including the investigation of thixotropic metal flow mechanics, the modelling and simulation of semisolid metal extrusion and further development of a fully thixotropic 3D printing system

Multi-Step Forming Simulation and Quality Control of Aluminum Alloy Automobile Rear Upper Control Arm

Aluminum alloy is widely used in automobile parts because of its light weight and good process performance. In view of the complex structure of aluminum alloy automobile rear upper control arms, multiple forming processes and the difficulty in quality control, in this paper, we propose a rolling-forging composite process to produce a rear upper control arm. Based on the reasonable volume distribution of the blank by cross-wedge rolling, multi-step forging was carried out. Finite element simulation of thermomechanically coupled multi-step forming was carried out using DEFORM software. Based on a comparison of the traditional process and the proposed rolling-forging composite forming process, we concluded that the rolling-forging composite process can greatly reduce the material cost and the forming force, resulting in superior product performance. The coarse-grain structure of products at different process temperatures was analyzed by a crystal-phase experiment. The results show that the process temperature of the multi-step process, as well as the heat treatment temperature and time have an important influence on the coarse-grain structure of the product. The optimal preheating temperatures for preforging and final forging dies were determined to be 335 °C and 350 °C, respectively; a preheating temperature of 530 °C and a solution time of 45 min resulted in the least coarse-grain surface structure. The research results provide a theoretical basis for improving the multi-step forming quality of automobile rear upper control arms

Wogonin Suppresses the Activity of Matrix Metalloproteinase-9 and Inhibits Migration and Invasion in Human Hepatocellular Carcinoma

As one of the major active ingredients in Radix Scutellariae, wogonin has been shown to be associated with various pharmacological activities on cancer cell growth, apoptosis, and cell invasion and migration. Here, we demonstrated that wogonin may harbor potential anti-metastatic activities in hepatocarcinoma (HCC). The anti-metastasis potential of wogonin and its underlying mechanisms were evaluated by ligand–protein docking approach, surface plasmon resonance assay, and in vitro gelatin zymography studies. Our results showed that wogonin (100 μM, 50 μM) suppressed MHCC97L and PLC/PRF/5 cells migration and invasion in vitro. The docking approach and surface plasmon resonance assay indicated that the potential binding affinity between wogonin and matrix metalloproteinase-9 (MMP-9) may lead to inhibition of MMP-9 activity and further leads to suppression of tumor metastasis. This conclusion was further verified by Western blot results and gelatin zymography analysis. Wogonin might be a potent treatment option for disrupting the tumor metastasis that favors HCC development. The potential active targets from computational screening integrated with biomedical study may help us to explore the molecular mechanism of herbal medicines

Angiogenin promotes U87MG cell proliferation by activating NF-κB signaling pathway and downregulating its binding partner FHL3.

Angiogenin (Ang) is known to induce cell proliferation and inhibit apoptosis by cellular signaling pathways and its direct nuclear functions, but the mechanism of action for Ang in astrocytoma is not yet clear. Astrocytoma is the most frequent one among various neurogliomas, of which a subtype known as glioblastoma multiforme (GBM) is the most malignant brain glioma and seriously influences the life quality of the patients. The expression of Ang and Bcl-xL were detected in 28 cases of various grades of astrocytoma and 6 cases of normal human tissues by quantitative real-time PCR. The results showed that the expression of Ang and Bcl-xL positively correlated with the malignant grades. Cytological experiments indicated that Ang facilitated human glioblastoma U87MG cell proliferation and knock-down of endogenous Ang promoted cell apoptosis. Furthermore, Ang activated NF-κB pathway and entered the U87MG cell nuclei, and blocking NF-κB pathway or inhibiting Ang nuclear translocation partially suppressed Ang-induced cell proliferation. The results suggested that Ang participated in the regulation of evolution process of astrocytoma by interfering NF-κB pathway and its nucleus function. In addition, four and a half LIM domains 3 (FHL3), a novel Ang binding partner, was required for Ang-mediated HeLa cell proliferation in our previous study. We also found that knockdown of FHL3 enhanced IκBα phosphorylation and overexpression of Ang inhibited FHL3 expression in U87MG cells. Together our findings suggested that Ang could activate NF-κB pathway by regulating the expression of FHL3. In conclusion, the present study established a link between Ang and FHL3 proteins and identifies a new pathway for regulating astrocytoma progression

SAK-HV Decreases the Self-Ubiquitination of MEKK1 to Promote Macrophage Proliferation via MAPK/ERK and JNK Pathways

SAK-HV is an anti-atherosclerosis recombinant fusion protein developed by our lab. Our study determined that SAK-HV promoted macrophage proliferation, of which the mechanism was explored by both RAW264.7 cells and primary macrophages. Mass spectrometric analysis and co-immunoprecipitation were combined to screen the SAK-HV-interacting proteins in RAW264.7 cells. Confocal microscopy was adopted to detect the localization of SAK-HV in cells. The results indicated that SAK-HV triggered macrophage proliferation via the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (ERK) and c-Jun N-terminal kinases (JNK) pathways by its SAK-mutant functional domain. We screened out Uba1 as the SAK-HV-interacting protein in the RAW264.7 cells and discovered their co-localization in the cytoplasm and nucleus. Inhibiting Uba1 significantly decreased the SAK-HV-induced macrophage proliferation. Thus, we postulated an attractive model of ubiquitination, in which the interactions between Uba1 and specific E2 enzymes are blocked by its interaction with SAK-HV. Based on this model, we detected the decreased self-ubiquitination of MEKK1 after SAK-HV treatment and concluded that SAK-HV inhibits the self-ubiquitination of MEKK1 via its SAK-mutant functional domain to activate MAPK/ERK and JNK pathways, promoting macrophage proliferation. This conclusion highly supported our hypothesized model of ubiquitination at the level of Uba1, which may represent a novel paradigm to promote macrophage proliferation by using the E1 enzyme (Uba1) as a switch

Mo₃S₁₃ Cluster-Based Cathodes for Rechargeable Magnesium Batteries: Reversible Magnesium Association/Dissociation at the Bridging Disulfur along with Sulfur–Sulfur Bond Break/Formation

Multivalent cation batteries are attracting increasing attention in energy-storage applications, but reversible storage of highly polarizing multivalent cations is a major difficulty for the electrode materials. In the present study, charge-delocalizing Mo3S13 cluster-based materials (crystalline (NH4)2Mo3S13 and amorphous MoSx) are designed and investigated as cathodes for rechargeable magnesium batteries. Both of the cathodes show high magnesium storage capacities (296 and 302 mAh g–1 at 100 mA g–1) and superior rate performances (76 and 80 mAh g–1 at 15 A g–1). A high area loading of 3.0 mg cm–2 could be achieved. These performances are of the highest level compared with those of reported magnesium storage materials. Further mechanism study and theoretical computation demonstrate the magnesium storage active sites are the bridging disulfur groups of the Mo3S13 cluster. The valence state of bridging disulfur decreases/increases largely during magnesiation/demagnesiation along with breaking/formation of the sulfur–sulfur bond, which makes the Mg-association/dissociation highly reversible. The sulfur–sulfur bond breaking and formation provides high reversible capacities. Prominently, the valence state increase and sulfur–sulfur bond formation of the bridging disulfur during charge weakens the bonding with Mg2+, significantly assisting the magnesium dissociation. The present study not only develops high-performance magnesium storage cathode materials but also demonstrates the importance of constructing favorable magnesium storage active sites in the high-performance cathode materials design. The findings presented herein are of great significance for the development of electrode materials for the storage of multivalent cations