Can the heptapeptide ASSIVSF of the ß2-adrenoceptor recognize ephedrine and pseudoephedrine epimers in a complex system?

Epimer separation is crucial in the field of analytical chemistry, separation science, and the pharmaceutical industry. No reported methods could separate simultaneously epimers or even isomers and remove other unwanted, co-existing, interfering substances from complex systems like herbal extracts. Herein, we prepared a heptapeptide-modified stationary phase for the separation of 1R,2S-(-)-ephedrine [(-)-Ephe] and 1S,2S-(+)-pseudoephedrine [(+)-Pse] epimers from Ephedra sinica Stapf extract and blood samples. The heptapeptide stationary phase was comprehensively characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The separation efficiency of the heptapeptide column was compared with an affinity column packed with full-length ß2-AR functionalized silica gel (ß2-AR column). The binding affinity of the heptapeptide with (+)-Pse was 3-fold greater than that with (-)-Ephe. Their binding mechanisms were extensively characterized by chromatographic analysis, ultraviolet spectra, circular dichroism analysis, isothermal titration calorimetry, and molecule docking. An enhanced hydrogen bonding was clearly observed in the heptapeptide-(+)-Pse complex. Such results demonstrated that the heptapeptide can recognize (+)-Pse and (-)-Ephe epimers in a complex system. This work, we believe, was the first report to simultaneously separate epimers and remove non-specific interfering substances from complex samples. The method was potentially applicable to more challenging sample separation, such as chiral separation from complex systems.

Numerical Simulation of Temperature Characteristics and Graphitization Mechanism of Diamond in Laser Powder Bed Fusion.

Thermal damage to diamonds is a major limitation in laser powder bed fusion (LPBF) processing of metal matrix diamond composites. In this paper, a numerical simulation model was established to describe the thermal effect of the Diamond-CuSn10 composite on the LPBF process. The simulation results show that the temperature of the diamond presents a double-peak structure, and the double-peak temperature curve shape can be modulated by modifying the laser scanning offset and the size of the diamond powder. And it suggests that the heat of the diamond mainly comes from the transfer of the molten pool. Then, combined with the experimental phenomenon, the mechanism of diamond graphitization in the LPBF process is analyzed. It indicates that since the surface defects of the diamond inhibit the heat conduction of the diamond, the temperature accumulates on the surface, leading to the graphitization of the diamond. Finally, based on this model, the potential of Ti-coated diamonds to prevent and reduce thermal damage in the LPBF process has been extensively studied. It is found that a Ti coating with low thermal conductivity can effectively reduce diamond temperature and improve diamond graphitization resistance. This study can provide a good method and basis for the preliminary selection of LPBF process parameters and the understanding of the graphitization mechanism of diamond tools.

Investigation of zeolite H-ß effect on pyrolysis of polystyrene by multiple kinetic analysis methods.

For studying the effects of H-ß zeolite on the pyrolysis of polystyrene (PS), non-isothermal thermogravimetric measurements were conducted in N2 under 5, 10, 15, and 20 K/min. The results show that the addition of 10 ~ 30 wt.% H-ß zeolite can significantly decrease the initial pyrolysis temperature of PS, indicative of the catalytic effect of zeolite used. Through kinetic analysis of the pyrolysis of PS blends, the isoconversional activation energies are calculated to be 121.8 ~ 191.9, 92.1 ~ 173.8, and 116.7 ~ 192.4 kJ/mol for the PS blends with zeolite loading of 10, 20, and 30 wt.%, respectively. Meanwhile, the pyrolysis degradation functions are determined through the Master-plots method integrated with a recently developed compensation-effect method to follow chemical reaction mechanism with the reaction order of 0.9, 1.0, and 0.6 for PS/zeolite blends of 10, 20, and 30 wt.% loading, and their pre-exponential factors are respectively calculated to be 6.18 × 108 ~ 5.71 × 1011, 2.36 × 106 ~ 9.23 × 1011, and 8.38 × 107 ~ 1.11 × 1012 min-1. Our work may provide some insights for how to better describe experimental results with theoretical predications and necessary information for performing any potential pyrolysis designs.

Capillary Tube Surface-Enhanced Raman Scattering Substrate and High-Sensitivity Molecule Detection.

Surface-enhanced Raman scattering (SERS) greatly improves molecule sensitivity compared with ordinary Raman spectroscopy. To excite and detect SERS efficiently, we fabricated glass-made microcapillary tubes decorated with silver nanoparticles inside them. The capillary tubes work as sample containers, where the required sample volume is in the order of a few nanoliters. The capillary tubes also play the role of optical waveguides. The tubes guide the excitation laser light through them so that the light illuminates whole silver nanoparticles inside the tubes at once. The tubes guide the SERS light to the tube end efficiently. The decoration of silver nanoparticles inside the tubes was performed by the silver mirror reaction. By making the tubes thinner and longer, highly sensitive SERS spectroscopy can be achieved. Our method would be a powerful tool for high-sensitivity molecule detection where the sample volume and concentration are extremely low.

Effects of ZSM-5 zeolite on pyrolysis of polystyrene: from stabilizing to catalyzing.

Nonisothermal pyrolysis measurements of polystyrene (PS)/ZSM-5 zeolite hybrids are conducted in N2 and thermogravimetric results have been kinetically analyzed with different isoconversional methods. Experimental results show that the addition of 5 and 10 wt.% ZSM-5 zeolite has increased the initial pyrolysis temperature of PS while the addition of 20 and 30 wt.% ZSM-5 zeolite can significantly decrease the initial pyrolysis temperature of PS. Elevated activation energy is resulted by adding low zeolite amount whereas reduced activation energy is obtained by adding high ZSM-5 amounts. The effect of zeolite ZSM-5 on PS pyrolysis can thus be observed to transfer from stabilizing to catalyzing. Furthermore, the pyrolysis mechanism functions of PS/zeolite hybrids are determined by integrating the master plots method with a new compensation effect method, and the most appropriate reaction models are found to be F0.92, F0.85, F0.56 and A1.32 for describing the pyrolysis of the PS/ZSM-5 hybrids with a zeolite loading of 5, 10, 20 and 30 wt.%, respectively. With the kinetic parameters thus available, the temperature-dependent mass conversion curves have been recast, leading to satisfactory simulations for PS/ZSM-5 hybrids.

Efficacy and safety of acupuncture combined with Xuefu Zhuyu Decoction on major adverse cardiovascular events after percutaneous coronary intervention: A protocol for systematic review and meta-analysis.

BACKGROUND: Percutaneous coronary intervention (PCI) is an effective treatment for coronary heart disease (CHD). With the merits of small trauma and high success rate, PCI can promote the fast recovery of CHD patients and greatly improve their prognosis and quality of life. However, because PCI does not eliminate the pathogenic factors that lead to atherosclerosis, major adverse cardiovascular events (MACEs) often occur after PCI. These events have become one of the principal factors affecting the long-term outcome of patients after PCI. In China, increasing attention is paid to the use of acupuncture combined with Xuefu Zhuyu Decoction (XFZYD) for the treatment of post-PCI MACEs in clinical practice. Nevertheless, this treatment approach still lacks evidence-based medical evaluation. In this study, a meta-analysis was conducted to evaluate the effectiveness and safety of acupuncture combined with XFZYD in the treatment of MACEs after PCI. METHODS: Randomized controlled trials on the efficacy and safety of acupuncture combined with XFZYD for the treatment of MACEs after PCI were retrieved from CNKI, WanFang, PubMed, Embase, Cochrane Library, Google Scholar and Web of Science databases from the time of database establishment to October 2022. The papers were screened strictly according to the inclusion and exclusion criteria, and the quality of the included studies was assessed using the Risk of Bias 2 (RoB 2) tool. Raw data were extracted from the studies and then a meta-analysis was made using RevMan 5.3 software. RESULTS: The results of this meta-analysis will be submitted to a peer-reviewed journal for publication. CONCLUSION: This study will summarize the latest evidence for the efficacy and safety of acupuncture combined with XFZYD in the treatment of MACEs after PCI.REGISTRATION NUMBER: CRD42022365657.

In Vitro and In Vivo Efficacy of Albendazole Chitosan Microspheres with Intensity-Modulated Radiation Therapy in the Treatment of Spinal Echinococcosis.

Currently, there is a lack of clinically safe and effective treatment for spinal cystic echinococcosis (CE). Recent studies have shown that albendazole chitosan microspheres (ABZ-CS-MPs) and irradiation have certain anti-abdominal echinococcosis ability, so this study aims to compare the in vitro and in vivo therapeutic effects of ABZ-CS-MPs, intensity-modulated radiation therapy (IMRT), and combination therapy on spinal echinococcosis. First, protoscoleces were processed by different treatments to evaluate their respective antiechinococcosis effects by monitoring the viability change of protoscoleces. Then, the apoptotic status of protoscoleces was evaluated by detecting the changes of mitochondrial membrane potential, the expression of apoptosis proteins, and the ultrastructural alterations of protoscoleces. After that, we constructed a gerbil model of spinal CE and further applied B-ultrasound and magnetic resonance imaging (MRI) technology to assess the size of hydatid in vivo. Finally, the cysts were obtained and weighed to compare the inhibition rate in different groups. The combined therapy increased protoscoleces mortality to over 90% after 18 days, which showed the highest scolicidal effect. Moreover, confocal imaging, expression of apoptotic proteins, and ultrastructural changes of protoscoleces showed the highest apoptotic rate in this group. In vivo, the combination treatment also exhibited the highest cyst inhibition rate (61.4%). In conclusion, our results showed that ABZ-CS-MPs combined with IMRT could be a new treatment option for spinal CE. We also provided a method to evaluate the growth and metastasis of hydatid in animals with B-ultrasound and MRI technologies.

LINC00943 knockdown attenuates MPP+-induced neuronal damage via miR-15b-5p/RAB3IP axis in SK-N-SH cells.

OBJECTIVES: Parkinson's disease (PD) is a neurodegenerative problem correlated with neuronal damage. Long noncoding RNAs (lncRNAs) are implicated in neuronal damage in PD development. This research aims to analyze the function and mechanism of LINC00943 in 1-methyl-4-phenylpyridinium (MPP+)-caused neuronal injury. METHODS: MPP+-challenged SK-N-SH cells served as a PD-like model of neuronal damage. LINC00943, microRNA-15b-5p (miR-15b-5p) and RAB3A interacting protein (RAB3IP) abundances were examined via quantitative reverse transcription polymerase chain reaction or western blot. MPP+-caused neuronal damage was assessed via cell viability, apoptosis, inflammatory injury and oxidative injury. The association between miR-15b-5p and LINC00943 or RAB3IP was determined via dual-luciferase reporter analysis and RNA immunoprecipitation. RESULTS: LINC00943 abundance was up-regulated in MPP+-challenged SK-N-SH cells. LINC00943 silence alleviated MPP+-caused decrease of cell viability and elevation of apoptosis, inflammatory injury and oxidative injury. miR-15b-5p was inhibited via LINC00943, and miR-15b-5p inhibition reversed knockdown of LINC00943-mediated suppression of MPP+-induced neuronal damage. RAB3IP was targeted via miR-15b-5p, and LINC00943 could regulate RAB3IP via miR-15b-5p. miR-15b-5p addition mitigated MPP+-induced neuronal damage through decreasing RAB3IP. CONCLUSION: LINC00943 inhibition alleviated MPP+-induced neuronal injury via miR-15b-5p/RAB3IP axis, indicating a potential target for treatment of PD.

Interleukin-1ß increased the expression of protease-activated receptor 4 mRNA and protein in dorsal root ganglion neurons.

Protease-activated receptor-4 (PAR4) is localized in primary sensory neurons and is believed to implicate in the modulation of nociceptive mechanisms. The pro-inflammatory cytokine interleukin-1ß (IL-1ß) is involved in the generation of hyperalgesia in pathological states such as neuropathy and inflammation. Previous studies have shown that IL-1ß enhances the expression of PAR4 in many cell types but the effect of this cytokine on primary sensory neuron PAR4 expression is less clear. In the present study, we evaluated in rat dorsal root ganglion (DRG) neurons the influence of IL-1ß on PAR4 mRNA and protein levels after IL-1ß intraplantar injection into the hind-paw or treatment of cultured DRG neurons. The expression of PAR4 in cultured DRG neurons was also assessed after treatment with IL-1ß with pre-addition of phorbol-12-myristate 13-acetate (PMA, a PKC activator) or chelerythrine chloride (a PKC inhibitor). We found that IL-1ß intraplantar injection into the hind-paw or long-term exposure of cultured DRG neurons to IL-1ß significantly increased the proportion of DRG neurons expressing PAR4 immunoreactivity. Real-time PCR and western blotting showed that IL-1ß treatment also significantly elevated PAR4 mRNA and protein levels in DRG neurons. This IL-1ß effect was enhanced in DRG neurons when DRG cultures were pre-treatment with the PMA. But pre-incubation with chelerythrine chloride strongly inhibited the IL-1ß-induced increase of PAR4 mRNA and protein levels. These results demonstrate that the expression of PAR4 mRNA and protein induced by IL-1ß is PKC signaling pathway dependent.