Subcritical water extraction of bioactive compounds from dry loquat (Eriobotrya japonica) leaves and characterization of triterpenes in the extracts

Medicinal properties of loquat leaf extracts (LLEs) are associated with their constituents of phenolic compounds and triterpenes. In this study, the efficacy of subcritical water extraction (SWE) technique was assessed by comparing with conventional solid-liquid extraction (CE) and Soxhlet extraction (SE). Results showed that the highest yields of total polyphenols were 82.7 ± 1.5 mgGAE/g leaf weight (LW), total flavonoids (54.1 ± 4.1 mgQE/g LW) and total triterpenoids (37.5 ± 3.2 mgUAE/g LW) were obtained by SWE compared to total polyphenols (61.8 ± 3.3 mgGAE/g LW), total flavonoids (43.2 ± 0.6 mgQE/g LW) and total triterpenoids (28.7 ± 2.3 mgUAE/g LW) extracted by SE and total polyphenols (50.3 ± 1.8 mgGAE/g LW), total flavonoids (40.4 ± 2.1 mgQE/g LW) and total triterpenoids (22.9 ± 3.2 mgUAE/g LW) obtained by CE. The extraction efficiency of triterpenes using SWE was about 1.7 times higher than those obtained using traditional extraction methods, and their main structural pattern of the cured extracts was comparable to the extracts obtained using traditional extraction methods.The infrared spectra obtained from the three extraction techniques appeared identical, but the variation in the intensity of the peak of absorption was visible among the three extraction techniques. The similarity of the infrared spectral pattern (peak coincided peak by peak) implies that the triterpenes in the extract obtained by the three techniques were identical by LC/MS. The findings of this study have demonstrated that SWE can be employed as an alternative green extraction technology to get important phytochemicals from plant sources.Keywords: Chinese loquat leaf, Eriobotrya japonica, subcritical water extraction, triterpen

A New Approach to Synthesize of 4-Phenacylideneflavene Derivatives and to Evaluate Their Cytotoxic Effects on HepG2 Cell Line

In this study, a convenient approach and green procedure for the synthesis of 4-phenacylideneflavenes has been developed from the reaction between 2,4-dihydroxybenzaldehyde and substituted acetophenones using boric acid as a catalyst in polyethylene glycol 400. Seven 4-phenacylideneflavenes were synthetized and their structures were confirmed by NMR and mass spectral analyses. Meanwhile, their possible mechanism of formation was also discussed. These products were found to have potential cytotoxic effect on HepG2 cell line with IC50 values from 12.5 to 50 µM

Malignant melanoma of the penis and urethra: one case report

We present a case of a patient with malignant melanoma of the glans penis and urethra, which was found in a 53-year-old man with nonhealing ulcerative penile lesion and bilateral, clinically palpable inguinal lymphadenopathies at diagnosis. A diagnostic biopsy showed the characteristics of a melanoma. We treated the patient with total penectomy and bilateral inguinal lymph node dissection. After surgery, chemotherapy with bleomycin, vincristine and cisplatin and immunotherapy with thymosin injection were started. No recurrence or metastasis occurred during the 3 years after the operation. Melanoma of the penis is very rare, and early diagnosis is important because the patient prognosis is very poor

Stability and performance of in-situ formed phosphosilicate nanoparticles in phosphoric acid-doped polybenzimidazole composite membrane fuel cells at elevated temperatures

One of the effective strategies to pursue the highly durable high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) is to introduce inorganic fillers to the phosphoric acid-doped polybenzimidazole (PA/PBI) membranes. Among the inorganic fillers, phosphates such as phosphosilicate are effective in mitigating acid loss at elevated temperatures (200–300 °C). In this paper, the effect of in situ formed phosphosilicate on the performance and stability of SiO2/PA/PBI composite membranes is studied in detail. The mechanical properties and electrochemical performances of the in situ formed SiO2/PA/PBI membranes depend strongly on the content of in situ formed Si5P6O25 fillers and its distribution and microstructure in the membrane. Such in situ formed SiO2/PA/PBI composite membranes show a high conductivity of 53.5 mS cm−1 at 220 °C. The assembled single cell shows a maximum peak power density (PPD) of 530.6 mW cm−2 and excellent stability at elevated temperature of 220 °C for over 130 h. The exceptional stability at 220 °C is most likely due to the existence of predominant amorphous phosphosilicate phases in the in situ formed SiO2/PA/PBI composite membranes, which inhibits the evaporation and leaching of PA at elevated temperatures. The results indicate the practical application of in situ formed SiO2/PA/PBI composite membranes for HT-PEMFCs

Tuning synergy between nickel and iron in Ruddlesden–Popper perovskites through controllable crystal dimensionalities towards enhanced oxygen-evolving activity and stability

Ni–Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction (OER) in water electrolysis. However, understanding and mastering the synergy of Ni and Fe remain challenging. Herein, we report that the synergy between Ni and Fe can be tailored by crystal dimensionality of Ni, Fe-contained Ruddlesden–Popper (RP)-type perovskites (La0.125Sr0.875)n+1(Ni0.25Fe0.75)nO3n+1 (n = 1, 2, 3), where the material with n = 3 shows the best OER performance in alkaline media. Soft X-ray absorption spectroscopy spectra before and after OER reveal that the material with n = 3 shows enhanced Ni/Fe–O covalency to boost the electron transfer as compared to those with n = 1 and n = 2. Further experimental investigations demonstrate that the Fe ion is the active site and the Ni ion is the stable site in this system, where such unique synergy reaches the optimum at n = 3. Besides, as n increases, the proportion of unstable rock-salt layers accordingly decreases and the leaching of ions (especially Sr2+) into the electrolyte is suppressed, which induces a decrease in the leaching of active Fe ions, ultimately leading to enhanced stability. This work provides a new avenue for rational catalyst design through the dimensional strategy

Organic Photochemistry-Assisted Nanoparticle Segregation on Perovskites

Summary The segregation (or exsolution) of nanoparticles (NPs) on the surface of perovskite oxide parents has emerged as an advanced technology to design functional materials for renewable energy. However, this process relies heavily upon lengthy reduction (800–1,200 K) in hydrogen-rich environments to facilitate the electron transfer from hydrogen to oxides, making this process costly. Here, we show that, in addition to thermal driving forces, photo-illumination can drive electron donation and facilitate the electron harvesting on perovskite directly. This results in segregation of NPs at room temperature with the assistance of trialkyl amine as a hole acceptor. A proton-coupled electron transfer catalytic cycle is suggested to explain this unusual electron transfer pathway, which is redox neutral and an intrinsically closed cycle. The practicality of this process is demonstrated by the improved performance in a trial electrocatalytic oxygen evolution reaction. This work suggests a promising design principle for perovskite functionalization

Induction of cytoprotective autophagy in PC-12 cells by cadmium

AbstractLaboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased, and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity

Development of In Situ Formed Metal Pyrophosphates (MP2O7, Where M = Sn, Ti, and Zr)/PA/PBI Based Composite Membranes for Fuel Cells

Development of high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) at elevated temperatures is important for the enhancement of tolerance toward CO impurities and for the development of non-precious metal catalysts. The key challenge in such HT-PEMFCs is the high temperature polymer electrolyte membranes. Herein, the development of in situ formed metal pyrophosphates (MP2O7, where M = Sn, Ti, and Zr) in phosphoric acid doped polybenzimidazole (PA/PBI) composite membranes for HT-PEMFCs is reported. The formation mechanism of MP2O7, and characteristics of MP2O7/PA/PBI composite membranes are studied in detail. In contrast to the rapid decay in performance of pristine PA/PBI membrane cells, the in situ formed MP2O7/PA/PBI composite membranes show significantly higher proton conductivity, improved performance, and stability at elevated temperatures of 200–250 °C. The best results are obtained on the in situ formed SnP2O7/PA/PBI composite membrane cells, exhibiting a high peak power density of 476 mW cm−2 and proton conductivity of 51.3 mS cm−1 at 250 °C. The excellent durability of SnP2O7/PA/PBI composite membrane is due to the uniform distribution of in situ formed SnP2O7 nanoparticles in PBI membranes and the formation of a gel-like region, thin and irregular amorphous layer on the SnP2O7 with the high acid retention ability. This effectively alleviates the PA leaching at elevated temperatures of the new HT-PEMFCs

Identifying a Universal Activity Descriptor and a Unifying Mechanism Concept on Perovskite Oxides for Green Hydrogen Production

Producing indispensable hydrogen and oxygen for social development via water electrolysis shows more prospects than other technologies. Although electrocatalysts have been explored for centuries, a universal activity descriptor for both hydrogen-evolution reaction (HER) and oxygen-evolution reaction (OER) is not yet developed. Moreover, a unifying concept is not yet established to simultaneously understand HER/OER mechanisms. Here, the relationships between HER/OER activities in three common electrolytes and over ten representative material properties on 12 3d-metal-based model oxides are rationally bridged through statistical methodologies. The orbital charge-transfer energy (Δ) can serve as an ideal universal descriptor, where a neither too large nor too small Δ (≈1 eV) with optimal electron-cloud density around Fermi level affords the best activities, fulfilling Sabatier's principle. Systematic experiments and computations unravel that pristine oxide with Δ ≈ 1 eV possesses metal-like high-valence configurations and active lattice-oxygen sites to help adsorb key protons in HER and induce lattice-oxygen participation in the OER, respectively. After reactions, partially generated metals in the HER and high-valence hydroxides in the OER dominate proton adsorption and couple with pristine lattice-oxygen activation, respectively. These can be successfully rationalized by the unifying orbital charge-transfer theory. This work provides the foundation of rational material design and mechanism understanding for many potential applications