RESUMO
Gold-catalyzed reactions, which have been widely explored over the past several years, are powerful tools in organic synthesis to access complex molecular frameworks, and some corresponding excellent reviews have been reported. However, little attention has been paid to summarize the reactions of strained small-ring-containing molecules catalyzed by gold. This critical review mainly puts its emphasis on the recent progress in the field of gold-catalyzed transformations of cyclopropyl-, cyclopropenyl-, epoxy- and aziridinyl-containing molecules. The rapid construction of interesting building blocks in organic synthesis from strained small rings catalyzed by gold has been summarized in this review (106 references).
RESUMO
Using diammonium hydrogen phosphate as an activator and N and P source and and bamboo chips as the carbon source, N, P co-doped activated carbon was prepared by one-step pyrolysis and used to efficiently remove La3+ in aqueous solutions. The effects of activation temperature and pH value on the adsorption performance of La3+ were analyzed, and the activation and adsorption mechanisms were explored using TG-IR, SEM-EDX, pore structure, XPS, and hydrophilicity. The results showed that diammonium hydrogen phosphate easily decomposed at a high temperature to produce ammonia and phosphoric acid, which activated the material and promoted the increase in the specific surface area and pore volume of the activated carbon. As an N and P source, the addition of diammonium hydrogen phosphate successfully achieved the N, P co-doping of activated carbon, and the introduction of N- and P-containing functional groups was the key to enhance the adsorption of La3+. Among them, graphitic nitrogen could provide interactions between La3+-π bonds, and C-P=O and C/P-O-P could provide active sites for the adsorption of La3+ through complexation and electrostatic interaction. The adsorption of La3+ on N, P co-doped activated carbons was endothermic and spontaneous, and the adsorption process conformed to the Langmuir isotherm and secondary kinetic model. Under the process conditions of an activation temperature of 900â and pH=6, the adsorption capacity of the N, P co-doped activated carbon was as high as 55.18 mg·g-1, which was 2.53 times higher than that of the undoped sample, and its adsorption selectivity for La3+ in the La3+/Na+and La3+/Ca2+ coexistence systems reached 93.49% and 82.49%, respectively. Additionally, the removal efficiency remained above 54% after five successive adsorption-desorption cycle experiments.
RESUMO
OBJECTIVE: To investigate the effects of H(2) Relaxin (Relaxin) on airway remodeling and the expression of cyclin D(1) in a murine model of chronic asthma. METHODS: Forty BALB/c mice were randomly divided into 4 groups:a normal control group, an asthma group, a vehicle control group and a relaxin treatment group, with 10 mice in each. The mice were sensitized and challenged with ovalbumin (OVA) to establish the chronic asthmatic model. The vehicle control group and the relaxin treatment group were subcutaneously injected with saline and relaxin (0.25 mg × kg(-1)× d(-1))respectively. Alteration of the airway inflammation and collagen deposition were observed by haematoxylin-eosin (HE) and Masson staining. Hydroxyproline in the lung was measured by enzyme linked immunosorbent assay (ELISA). The expression of α-smooth muscle actin (α-SMA) in lungs was evaluated by immunohistochemistry. The protein expression and the mRNA of cyclin D(1) were detected by Western blot and RT-PCR respectively. RESULTS: There were inflammatory cell infiltration, airway stenosis, bronchial smooth muscle hypertrophy and increased collagen deposition in the asthmatic group and the vehicle control group; but these changes were significantly ameliorated in the relaxin treatment group. The area of the α-SMA-stained smooth muscle layer in the asthmatic group and the vehicle control group was significantly greater than that in the control group (all P < 0.05), while administration of relaxin decreased the α-SMA immunostained area (all P < 0.05). The lung hydroxyproline content in the asthmatic and the vehicle groups [(0.68 ± 0.10) mg/g lung tissue, (0.67 ± 0.10) mg/g lung tissue] was significantly greater than that in the control group [(0.26 ± 0.05) mg/g lung tissue] (q = 16.61, 16.01 respectively, all P < 0.01). In contrast, treatment with relaxin significantly reduced the lung hydroxyproline content [(0.40 ± 0.06) mg/g lung tissue] compared with aforementioned 2 groups (q = 10.88, 10.26 respectively, all P < 0.05). The results of the Western blot analysis showed that the expression level of cyclin D(1) in the asthmatic and the vehicle groups [(1.38 ± 0.18), (1.50 ± 0.10)] was higher than that in the control group (0.38 ± 0.10) (q = 13.00, 14.65 respectively, all P < 0.05), while it was significantly decreased in the relaxin group (0.72 ± 0.13) (q = 8.51, 10.16 respectively, all P < 0.05). There were no differences in all of the parameters between the asthmatic group and the vehicle group (P > 0.05). CONCLUSION: Relaxin alleviated airway inflammation, airway smooth muscle thickening and airway remodelling in a murine model of chronic asthma, partially by down-regulating the expression level of cyclin D(1).