Melting entropy of crystals determined by electron-beam-induced configurational disordering.

Upon melting, the molecules in a crystal explore numerous configurations, reflecting an increase in disorder. The molar entropy of disorder can be defined by Boltzmann's formula ΔSd = Rln(Wd), where Wd is the increase in the number of microscopic states, so far inaccessible experimentally. We found that the Arrhenius frequency factor A of the electron diffraction signal decay provides Wd through an experimental equation A = AINTWd, where AINT is an inelastic scattering cross section. The method connects Clausius and Boltzmann experimentally and supplements the Clausius approach, being applicable to a femtogram quantity of thermally unstable and biomolecular crystals. The data also showed that crystal disordering and crystallization of melt are reciprocal, both governed by the entropy change but manifesting in opposite directions.

Hierarchical Porous Bimetallic FeMn Metal-Organic Framework Gel for Efficient Activation of Peracetic Acid in Antibiotic Degradation.

Effective techniques for eliminating antibiotics from water environments are in high demand. The peracetic acid (PAA)-based advanced oxidation process has recently drawn increasing attention for its effective antibiotic degrading capability. However, current applications of PAA-based techniques are limited and tend to have unsatisfactory performance. An additional catalyst for PAA activation could provide a promising solution to improve the performance of PAA. Bulky metal-organic framework gels (MOGs) stand out as ideal catalysts for PAA activation owing to their multiple advantages, including large surface areas, high porosity, and hierarchical pore systems. Herein, a bimetallic hierarchical porous structure, i.e., FeMn13BTC, was synthesized through a facile one-pot synthesis method and employed for PAA activation in ofloxacin (OFX) degradation. The optimized FeMn MOG/PAA system exhibited efficient catalytic performance, characterized by 81.85% OFX degradation achieved within 1 h owing to the specific hierarchical structure and synergistic effect between Fe and Mn ions, which greatly exceeded the performance of the only PAA-catalyzed system. Furthermore, the FeMn MOG/PAA system maintained >80% OFX degradation in natural water. Quenching experiments, electron spin resonance spectra, and model molecular degradation revealed that the primary reactive oxygen species responsible for the catalytic effect was R-O•, especially CH3C(=O)OO•, with minor contributions of •OH and 1O2. Overall, introduction of the MOG catalyst strategy for PAA activation achieved high antibiotic degradation performance, establishing a paradigm for the design of heterogeneous hierarchical systems to broaden the scope of catalyzed water treatment applications.

Identification of Bulbocodin D and C as novel STAT3 inhibitors and their anticancer activities in lung cancer cells.

Cancer stands as one of the predominant causes of mortality globally, necessitating ongoing efforts to develop innovative therapeutics. Historically, natural products have been foundational in the quest for anticancer agents. Bulbocodin D (BD) and Bulbocodin C (BC), two bibenzyls derived from Pleione bulbocodioides (Franch.) Rolfe, have demonstrated notable in vitro anticancer activity. In human lung cancer A549 cells, the IC50s for BD and BC were 11.63 and 11.71 µmol·L-1, respectively. BD triggered apoptosis, as evidenced by an upsurge in Annexin V-positive cells and elevated protein expression of cleaved-PARP in cancer cells. Furthermore, BD and BC markedly inhibited the migratory and invasive potentials of A549 cells. The altered genes identified through RNA-sequencing analysis were integrated into the CMap dataset, suggesting BD's role as a potential signal transducer and activator of transcription 3 (STAT3) inhibitor. SwissDock and MOE analyses further revealed that both BD and BC exhibited a commendable binding affinity with STAT3. Additionally, a surface plasmon resonance assay confirmed the direct binding affinity between these compounds and STAT3. Notably, treatment with either BD or BC led to a significant reduction in p-STAT3 (Tyr 705) protein levels, regardless of interleukin-6 stimulation in A549 cells. In addition, the extracellular signal-regulated kinase (ERK) was activated after BD or BC treatment. An enhancement in cancer cell mortality was observed upon combined treatment of BD and U0126, the MEK1/2 inhibitor. In conclusion, BD and BC emerge as promising novel STAT3 inhibitors with potential implications in cancer therapy.

Sequential Sol-Gel Self-Assembly and Nonclassical Gel-Crystal Transformation of the Metal-Organic Framework Gel.

Metal-organic framework (MOF) gel, an emerging subtype of MOF structure, is unique in formation and function; however, its evolutionary process remains elusive. Here, the evolution of a model gel-based MOF, UiO-66(Zr) gel, is explored by demonstrating its sequential sol-gel self-assembly and nonclassical gel-crystal transformation. The control of the sol-gel process enables the observation and characterization of structures in each assembly stage (phase-separation, polycondensation, and hindered-crystallization) and facilitates the preparation of hierarchical materials with giant mesopores. The gelation mechanism is tentatively attributed to the formation of zirconium oligomers. By further utilizing the pre-synthesized gel, the nonclassical gel-crystal transformation is achieved by the modulation in an unconventional manner, which sheds light on crystal intermediates and distinct crystallization motions ("growth and splitting" and "aggregation and fusion"). The overall sol-gel and gel-crystal evolutions of UiO-66(Zr) enrich self-assembly and crystallization domains, inspire the design of functional structures, and demand more in-depth research on the intermediates in the future.

Two new bibenzyls from Pleione grandiflora (Rolfe) Rolfe and their antioxidant activity.

Two new bibenzyls (1 and 2) were isolated from the pseudobulbs of Pleione grandiflora (Rolfe) Rolfe along with six known compounds, including isoarundinin I (3), isoarundinin II (4), bulbocodin D (5), batatasin III (6), 5,3'-dihydroxy- 4-(p-hydroxybenzyl)-3-methoxybibenzyl (7) and shancigusin F (8). Their structures were established on the basis of spectroscopic methods. These compounds showed potent DPPH free radical scavenging effects with IC50 values ranging from 49.72 ± 0.35 µM to 65.41 ± 0.49 µM.

Hierarchical porous melamine sponge@MIL-101-Fe-NH2 composite as Fenton-like catalyst for efficient and rapid tetracycline hydrochloride removal.

Metal-organic frameworks have been investigated in Fenton-like catalysis for tetracycline hydrochloride degradation, a widely used antibiotic which threatens the growth and health of creatures. However, powder phase and absence of large pores limit the materials' degradation performance and application. In this work, a hierarchical macro-meso-microporous composite melamine sponge@MIL-101-Fe-NH2 was firstly designed and constructed. While the micropores provided plenty of active sites to generate reactive oxygen species, the macropores and mesopores accelerated mass transfer. Besides, MIL-101-Fe-NH2 particles dispersed on melamine sponge individually, exposing more catalytic sites and avoiding inactivation caused by aggregation compared to powder catalysts. Its catalysis performance for tetracycline hydrochloride degradation was evaluated through changing various influence factors like H2O2 concentration, catalyst amount, pH and coexisting ions. Different from the preference of homogenous Fenton catalysts for pH 2-4, the composite displayed the most effective degradation at a subacid environment closer to nature with 77.24% in 30 min. Owing to the synergistic effect of hierarchical porous structure and monodispersed nanoparticles, the composite exhibited faster reaction rate and longer persistence compared to powder MIL-101-Fe-NH2. Easy recycling and less ion leaching made it advantages for practical application. •OH, •O2- and 1O2 active species contributed together to the degradation and two main possible degradation pathways were put forward based on 35 detected intermediates.

Discovery of glucosyloxybenzyl 2-hydroxy-2-isobutylsuccinates with anti-inflammatory activities from Pleione grandiflora.

Six new glucosyloxybenzyl 2-hydroxy-2-isobutylsuccinates, pleionesides A-F (1-6), along with two known compounds (7, 8) were obtained from the pseudobulbs of Pleione grandiflora (Rolfe) Rolfe. The structures and absolute configurations of new compounds were established by HRESIMS and NMR data, along with acidic hydrolysis and alkaline hydrolysis experiments. Compounds 1-6 were tested for their anti-inflammatory activities on LPS-induced BV2 microglial cells. Amoung them, 2, 4 and 5 showed moderate activities with IC50 values of 73.4, 32.8 and 57.1 µM, respectively, compared with the positive control quercetin with an IC50 value of 28.3 µM.

A Showcase of Green Chemistry: Sustainable Synthetic Approach of Zirconium-Based MOF Materials.

Zirconium-based metal-organic framework materials (Zr-MOFs) have more practical usage over most conventional benchmark porous materials and even many other MOFs due to the excellent structural stability, rich coordination forms, and various active sites. However, their mass-production and application are restricted by the high-cost raw materials, complex synthesis procedures, harsh reaction conditions, and unexpected environmental impact. Based on the principles of "Green Chemistry", considerable efforts have been done for breaking through the limitations, and significant progress has been made in the sustainable synthesis of Zr-MOFs over the past decade. In this review, the advancements of green raw materials and green synthesis methods in the synthesis of Zr-MOFs are reviewed, along with the corresponding drawbacks. The challenges and prospects are discussed and outlooked, expecting to provide guidance for the acceleration of the industrialization and commercialization of Zr-MOFs.

[A new lignan from Euscaphis konishii].

The chemical constituents from the extract of the twigs of Euscaphis konishii with anti-hepatoma activity were investigated, twelve compounds by repeated chromatography with silica gel, Sephadex LH-20 and preparative-HPLC. The structures of the chemical components were elucidated by spectroscopy methods, as konilignan(1),(7R, 8S)-dihydrodehydrodico-niferylalcohol-9-O-ß-D-glucopyranoside(2),illiciumlignan B(3),threo-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-panediol(4),erythro-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-panediol(5), matairesinol(6), wikstromol(7), isolariciresinol(8),(+)-lyoniresinol(9), 4-ketopinoresinol(10), syringaresin(11), and vladinol D(12). Among them, compound 1 is a new lignan. Compounds 10 and 12 had moderate inhibitory activity on HepG2 cells, with IC_(50) values of 107.12 µmol·L~(-1) and 183.56 µmol·L~(-1), respectively.

[Changes in water state and soluble protein contents of wampee axes during inducing desiccation tolerance by sucrose preculture].

Progressively increasing sucrose concentration of culture medium could increase desiccation tolerance of wampee [Clausena lansium (Lour.) Skeels] axes. The changes in water state and soluble proteins of axes during acquirement of desiccation tolerance were measured by differential scanning calorimeter (DSC) and SDS-PAGE. The results showed that the cooling and heating thermograms of sucrose-precultured axes were similar to those of the control; but there was a stepwise change in the heating thermograms of sucrose-precultured axes, implying that vitrification might occur in axes. Unfreezable water amounts of wampee axes were measured, the results showed that amounts of unfreezable water of sucrose-precultured axes and control were 25.4% and 25.9% (by the linear regression equation method), or 24.3% and 23.7% (by the heat of ice fusion method) respectively, which were not significantly different. The soluble protein content of sucrose-precultured axes was 68% higher than the control, and SDS-PAGE showed that a 20-kD protein markedly increased in content.

[Synthesis of heat shock proteins in developing maize embryo].

Labeling of protein in developing maize embryo with (35)S-Met showed that, the protein synthesis rate in heat shock (42 degrees C) was similar to that in the control (25 degrees C). Heat shock inhibited protein synthesis at 16 DAP, whereas it stimulated protein synthesis at 22 and 34 DAP. The pattern of SDS-PAGE showed that, a new set of heat shock proteins were induced after heat shock. At 16 DAP, heat shock induced 3 kinds of HSPs with molecular weight 86.4, 80.0 and 73.2 kD. And at 22 DAP, 7 kinds HSPs were induced with molecular weight 86.4, 80.0, 73.2, 24.4, 18.2, 16.8 and 13.6 kD. After 22 DAP, except 3 kinds of protein with molecular weight 73.2, 24.4 and 18.2 kD were induced turnover synthesis, other 4 kinds were increased by heat shock. The pattern of 2D-PAGE further suggested that, heat shock induced more than 20 kinds of HSPs at 22 and 28 DAP, especially the smHSP of 20-30 kD were more than 10 kinds. Western blot indicated that, BiP (HSP70) and PDI (HSP60) kept a high expression level during the embryo development, and failed to respond to heat shock.

[Induction of chilling tolerance and heat shock protein synthesis in rice seedlings by heat shock].

Heat shock applied to germinated rice seeds increased the chilling tolerance of seedlings. Comparison with the control, brief heat shock applied before chilling at 4 degrees C for 2 days and recovery at 25 degrees C for another 2 days decreased the permeability of cellular membranes and increased the content of proline in rice seedlings. Heat shock applied before chilling also increased the activities of superoxide dismutase, catalase, and peroxidase and the content of ascorbate in rice seedlings. In contrast, the lipoxygenase activity and the malondialdehyde content in the heat-shocked rice seedlings were lower than those in the control. Germinated rice embryos synthesized heat shock proteins of Mr 78, 70, 64, 46, 38, 24, 17 and 16 kD during heat shock. The results of Western blot suggested that the binding protein (Bip) of HSP70 play an important role in protecting the rice seedling against chilling damage.

[Changes in desiccation tolerance and cell ultrastructures of wampee axes induced by progressively raising sucrose concentration of culture medium].

The desiccation tolerance of wampee [Clausena lansium (Lour.) Skeels] axes was significantly increased when they were pre-cultured with woody plant medium with progressively increasing sucrose contents (27% --> 50% --> 60%). Most of the plumular axes could survive a moisture content as low as 18.8% and could regenerate plantlets. Results of electron microscopy showed that when the moisture content of the plumular axes of the control was brought down to 36.3%, the plasmolemma and vacuole disappeared, and the chloroplasts and mitochondria collapsed. Plate I-1-4) While plumular axes had been pre-cultured by progressive raising of sucrose concentration of culture medium and then desiccated to a moisture content of 35.8%, plasmolysis occurred in most of the cells, with dense cytoplasm and big starch grains in the chloroplast (Plate I-6-8, Plate II-9). Furthermore, after they were desiccated to a moisture content of 18.8%, severe plasmolysis was observed, most of the chloroplasts and mitochondria were partly injured (Plate II-10). The desiccative injury in cells of the plumular axes desiccated to a moisture content of 18.8% could be repaired after 4 d of rehydration (Plate II-11-16).