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Based on the global goals for cleaner production and sustainable development, the pyrolysis behavior of cephalosporin residues was studied by TG-MS method. The influence of full temperature window on the safe disposal of residues was analyzed based on the “3-2-2” and “1+1” of thermal analysis kinetics, and the gas by-products of thermal degradation were monitored. Results showed that the pyrolysis of distillation residues were divided into low and high-temperature zones, including six stages. Maximum error rate (8.55%) by multiple scan rate was presented based on “3-2-2” pattern and maximum total fluctuation (33.7) by single scan rate was presented based on “1+1” pattern, which implied that the comprehensive multi-level comparison method was very reliable. The E value “E” of six stages showed an increasing trend ranging 166.8 to 872.8 kJ/mol. LgA(mean) was 27.28. Most mechanism function of stage 1, 2 were Z-L-T equation (3D), stage 3, 4, 6 were Avrami-Erofeev equation (AE3, AE4, AE2/3) and stage 5 was Reaction Order (O2). In addition, various small molecular micromolecule substances were detected such as C2H4O, C2H6, NH3, CH4, CO2 under full temperature windows and a possible pyrolysis path of residues was provided.

Defining the denatured state ensemble (DSE) and disordered proteins is essential to understanding folding, chaperone action, degradation, and translocation. As compared with water-soluble proteins, the DSE of membrane proteins is much less characterized. Here, we measure the DSE of the helical membrane protein GlpG of Escherichia coli (E. coli) in native-like lipid bilayers. The DSE was obtained using our steric trapping method, which couples denaturation of doubly biotinylated GlpG to binding of two streptavidin molecules. The helices and loops are probed using limited proteolysis and mass spectrometry, while the dimensions are determined using our paramagnetic biotin derivative and double electron-electron resonance spectroscopy. These data, along with our Upside simulations, identify the DSE as being highly dynamic, involving the topology changes and unfolding of some of the transmembrane (TM) helices. The DSE is expanded relative to the native state but only to 15 to 75% of the fully expanded condition. The degree of expansion depends on the local protein packing and the lipid composition. E. coli's lipid bilayer promotes the association of TM helices in the DSE and, probably in general, facilitates interhelical interactions. This tendency may be the outcome of a general lipophobic effect of proteins within the cell membranes.

To improve the problem of difficulty in forming a complete and dense conversion film on the copper surface when using phytic acid alone，the conversion films containing phytic acid (PA) and different azole derivatives were prepared on copper surface by impregnation method.The hydrophobicity，corrosion resistance and surface morphology of the conversion films were characterized by contact angle tester，electrochemical workstation，scanning electron microscope and energy dispersive spectroscopy (EDS).The film formation mechanism of PA+BTA conversion film with the best corrosion resistance was analyzed using X-ray electron spectroscopy (XPS).Results showed that the corrosion resistance of conversion films formed by adding different azole derivatives was improved.The contact angle of the conversion film with benzotriazole (BTA) and phytic acid reached maximum value (135.51 °)，and the corrosion current density reached minimum value (2.050 × 10-7 A/cm2)，while the impedance value exceeding 90 kΩ.By observing the SEM morphology of PA+BTA conversion film，it was found that the conversion film was evenly distributed and dense on the surface of copper substrate.XPS analysis of the PA+BTA conversion film showed that both PA and BTA were involved in the formation of the conversion film.PA-Cu and BTA-Cu complexes were formed on the surface of copper substrate，which could effectively protect the substrate.

Single-molecule measurements of protein dynamics help unveil the complex conformational changes and transitions that occur during ligand binding and catalytic processes. Using high-resolution single-molecule nanocircuit techniques, we have investigated differences in the conformational dynamics and transitions of lysozyme interacting with three ligands: peptidoglycan substrate, substrate-based chitin analogue, and indole derivative inhibitors. While processing peptidoglycan, lysozyme followed one of the two mechanistic pathways for the hydrolysis of the glycosidic bonds: a concerted mechanism inducing direct conformational changes from open to fully closed conformations or a nonconcerted mechanism involving transient pauses in intermediate conformations between the open and closed conformations. In the presence of either chitin or an indole inhibitor, lysozyme was unable to access the fully closed conformation where catalysis occurs. Instead, lysozymes' conformational closures terminated at slightly closed, "excited" conformations that were approximately one-quarter of the full hinge-bending range. With the indole inhibitor, lysozyme reached this excited conformation in a single step without any evidence of rate-liming intermediates, but the same conformational motions with chitin involved three hidden, intermediate processes and features similar to the nonconcerted peptidoglycan mechanism. The similarities suggest that these hidden processes involve attempts to accommodate imperfectly aligned polysaccharides in the active site. The results provide a detailed glimpse of the enzyme-ligand interplay at the crux of molecular recognition, enzyme specificity, and catalysis.

Self-assembled materials capable of modulating their assembly properties in response to specific enzymes play a pivotal role in advancing 'intelligent' encapsulation platforms for biotechnological applications. Here, we introduce a previously unreported class of synthetic nanomaterials that programmatically interact with histone deacetylase (HDAC) as the triggering stimulus for disassembly. These nanomaterials consist of co-polypeptides comprising poly(acetyl L -lysine) and poly(ethylene glycol) blocks. Under neutral pH conditions, they self-assemble into particles. The hydrodynamic diameters of particles were typically withing the range of 108–190 nm, depending on degree of acetylation of the hydrophobic block. However, their stability is compromised upon exposure to HDACs, depending on enzyme concentration and exposure time. Our investigation, utilizing HDAC8 as the model enzyme, revealed that the primary mechanism behind disassembly involves a decrease in amphiphilicity within the block copolymer due to the deacetylation of lysine residues within the particles' hydrophobic domains. To elucidate the response mechanism, we encapsulated a fluorescent dye within these nanoparticles. Upon incubation with HDAC, the nanoparticle structure collapsed, leading to controlled release of the dye over time. Notably, this release was not triggered by denatured HDAC8, other proteolytic enzymes like trypsin, or the co-presence of HDAC8 and its inhibitor. We also demonstrated the biocompatibility and cellular effects of these materials in the context of drug delivery in different types of anticancer cell lines, such as MIA PaCa-2, PANC-1, cancer like stem cells (CSCs), and non-cancerous HPNE cells. We observed that the release of a model drug (such as a STAT3 pathway inhibitor, Napabucasin) can be loaded into these nanoparticles, with >90% of the dosage can be released over 3 h under the influence of HDAC8 enzyme in a controlled fashion. Further, we conducted a comprehensive computational study to unveil the possible interaction mechanism between enzymes and particles. By drawing parallels to the mechanism of naturally occurring histone proteins, this research represents a pioneering step toward developing functional materials capable of harnessing the activity of epigenetic enzymes such as HDACs. [ABSTRACT FROM AUTHOR]

Analysis of saturation recovery data from spin-labeled proteins is extended to include the amplitudes in addition to the recovery rates for two-site exchange. It is shown that the recovery amplitudes depend strongly on the exchange rate between states as well as their populations and this dependence provides a simple criterion to identify exchange rates in the 10–1000 kHz range. Analysis of experimental SR relaxation curves via the uniform penalty (UPEN) method allows for reliable identification of single, double, or other multiple-component traces, and global fitting of a set of relaxation curves using both relaxation rates and amplitudes determined from the UPEN fits allows for the estimation of exchange rate in the above domain. The theory is tested on simple model systems, and applied to the determination of conformational exchange rates in spin-labeled mutants of T4 Lysozyme and intestinal fatty acid binding protein. Finally, an example of T1-weighted spectral editing is provided for systems in the slow exchange limit.

High-speed rail (HSR) has significantly improved the accessibility of tourist destinations, thereby promoting the increase and gathering of tourist flow. In addition to promoting the development of tourism, the HSR may exacerbate the gap in regional tourism development. Thus, the tourism economic growth effect and distribution effect of HSR opening coexist. Existing studies are controversial regarding the growth effect. Moreover, they have not considered the distribution effect. Accordingly, it is urgent to test whether the HSR can become a promotion engine for the development of regional tourism or aggravate the development gap. Using provincial panel data of 20 ethnic regions in China from 2000 to 2017, this study evaluated the applicability of the difference-in-differences (DID) method through parallel trend testing and used DID to evaluate the impact of the HSR on tourism development in ethnic regions. In addition, three factors need to be considered to ensure robust estimation results. First, a placebo test is performed. According to the counterfactual hypothesis, the opening year of the HSR is advanced by two years, and the DID is used to perform an estimation again. Second, robustness tests are conducted using semiparametric-DID to perform an estimation and DID to perform an estimation by replacing the explanatory and control variables, respectively. Finally, the endogeneity test is conducted using Two-stage least squares method. The major research conclusions are as follows: 1) Overall, HSR has promoted the development of tourism in ethnic regions, with an average increase of 16.52% in total domestic tourist arrivals and of 23.29% in total domestic tourism revenue. Thus, HSR has a growth effect on the tourism economy in ethnic areas. Furthermore, HSR does not affect the gap in total domestic tourist arrivals among ethnic regions or in total domestic tourism income among ethnic regions. Hence, HSR does not have a distribution effect on the tourism economy in ethnic regions. 2) From the perspective of robustness, after replacing the variables and estimation methods, the HSR has a significant positive impact on the total domestic tourist arrivals and domestic tourism revenue in ethnic regions. That is, while it still has the growth effect of the tourism economy, it does not have the distribution effect, indicating that the overall estimation result is relatively robust. 3) From the perspective of the impact mechanism, HSR has a significant positive impact on GDP growth and industrial structure adjustment in ethnic regions, but it has no significant impact on population at the end of the year, passenger turnover, and cargo weekly transshipment volume. That is, the HSR has diffusion and structural effects but does not have a siphon or aisle effect in ethnic areas. Thus, the tourism economic growth effect of HSR in the minority areas is mainly due to the diffusion effect of HSR. Tourist flows from central cities or regions continue to flow to relatively remote ethnic regions and, simultaneously, promote the adjustment of the industrial structure in ethnic regions. As there is no siphon or aisle effect, HSR does not aggravate the regional tourism development gap. 4) From a dynamic standpoint, the growth effect of the HSR on the tourism economy in ethnic regions still lags. As time passes since the opening of HSR, its economic effect gradually weakens. Even if the opening time of HSR is extended, the distribution effect of HSR on the tourism economy in ethnic areas is still not observed. In general, this study examines the tourism economy of HSR. It considers its growth and distribution effects. This provides a basis for accurately evaluating the economic effects of HSR and guiding the inclusive development of regional tourism.