Selective growth of two-dimensional phosphorene on catalyst surface

Although the study of black phosphorene (BP) and its isomers has attracted enormous attention, the method of synthesizing high-quality samples in a large area is still pending. Here we explore the potential of using the chemical vapor deposition method to synthesize large-area two-dimensional (2D) phosphorene films on metal surfaces. Our ab initio calculations show that BP can be synthesized by using tin (Sn) as a catalyst, while one of its isomers, blue phosphorene (BLP), is very possible to be synthesized by using most other metals, such as Ag and Au. Besides, our study also suggests that the large binding energy between the 2D phosphorene and the active metal substrate may prohibit the exfoliation of the 2D phosphorene for real applications and, therefore, tin, silver and gold are predicted to be the most suitable catalysts for the synthesis of BP and BLP.

Enamel matrix proteins regulate hypoxia-induced cellular biobehavior and osteogenic differentiation in human periodontal ligament cells

Hypoxia is a crucial microenvironment for inflamed periodontal tissue and periodontal wound healing. Enamel matrix proteins (EMPs) potentially can promote the formation of new periodontium. The effects of EMPs on periodontal ligament cells under hypoxia, however, remain unclear. We investigated the effects of EMPs on cellular biobehavior and osteogenic differentiation of human periodontal ligament cells (hPDLCs) under hypoxia. Under cobalt chloride (CoCl₂)-induced hypoxia, cellular biobehavior of hPDLCs, including proliferation, attachment, spreading, and migration with or without EMPs, was evaluated by 3-(4, 5-dimethylthiazol- 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), cell counting, spreading area measurement and wound scratch assay. The osteogenic activity of hPDLCs was assessed using alkaline phosphatase (ALP) and alizarin red S staining (ARS). The expressions of osteogenic genes including runt related transcription factor 2 (Runx2), ALP, osteocalcin (OCN) and collagen type I (Col-I) were detected using real time quantitative PCR, western blot and immunocytochemistry assays. The biobehavior and osteogenic differentiation of hPDLCs were inhibited significantly under hypoxia. EMPs have no effect on cell proliferation under mimicked hypoxia. EMPs partly reversed the inhibitory effects of hypoxia, however, for other cellular biobehavior including attachment, spreading and migration, and markedly up-regulated osteogenic differentiation activities including ALP, mineralization ability and the expressions of osteogenic genes such as Runx2, ALP, osteocalcin, and collagen type I in hPDLCs under hypoxia. EMPs attenuate the hypoxic injury to cellular biobehavior and osteogenic differentiation in hPDLCs under hypoxia.

Pharmacological investigation of a HPLC/MS standardized three herbal extracts containing formulae (Bu-Shen-Yi-Qi-Tang) on airway inflammation and hypothalamic-pituitary-adrenal axis activity in asthmatic mice

Bu-Shen-Yi-Qi-Tang (BSYQT) which is prescribed on the basis of clinical experience is commonly used in clinic of traditional Chinese medicine (TCM) for asthma treatment. The components of BSYQT include Radix Astragali (RA), Herba Epimedii (HE) and Radix Rehmanniae (RR). The aim of this study was to screen extracts of BSYQT with best anti-inflammatory activity in asthmatic mice, and separate and identify the chemical compounds in them. Our results suggested that 60% ethanol extract of herbs (H60) and granules (G60) of BSYQT were the two extracts with best anti-inflammatory activity and effects of H60 were a little better than that of G60. High-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF-MS/MS) analysis of the major chemical compounds of H60 and G60 revealed that 56 and 42 peaks were identified separately in H60 and G60. Further analysis revealed that 38 compounds were identified shared by H60 and G60, and 18 compounds were only in H60. There were 25 compounds in HE, 6 compounds in RR and 7 compounds in RA in the 38 compounds shared by G60 and H60. These 38 chemical components were tentatively considered the material basis of the anti-inflammatory activity of G60 and H60. The differences in the amount of the 38 chemical components as well as the 18 chemical components only in H60 were tentatively considered responsible for the activity differences between H60 and G60. In conclusion, these results suggested that extracts of BSYQT had inhibitory effects on airway inflammation in asthmatic mice, and H60 and G60 demonstrated the best anti-inflammatory activity. The 38 chemical compounds shared by H60 and G60 were responsible for their anti-inflammatory activity in asthmatic mice, and the differences in chemical compounds contents and amounts between H60 and G60 were responsible for this activity differences. This work would provide support for further pharmacodynamic material basis study of BSYQT.

[Experimental study on antagonism of ginkgolides against effect of platelet-activating factor on lung strip of guinea pigs]

OBJECTIVE

To investigate the action of ginkgolides antagonizing the contraction of guinea pigs' lung strip induced by the mixture of platelet-activating factor (PAF) and platelets and its effect of preventing the PAF caused damage of beta-adrenergic receptors.

METHODS

The contraction of guinea pigs' isolated lung strip was measured.

RESULTS

The mixture of PAF and platelet could produce a serious contraction of lung strip, the IC50 reached 4.69 x 10(-7) mol/L, while the contraction induced by PAF alone was relatively mild, its IC50 only 6.66 x 10(-4) mol/L, the difference between them was significant (P < 0.05). When the platelets were preincubated with ginkgolides for 10 minutes in Tris-Tyrode's buffered saline, the effects of PAF and platelets mixture were significantly inhibited (P < 0.05). Exposure of guinea pigs' lung strip to PAF in vitro resulted in a loss of beta-adrenergic receptors and weakened its respones to isoproterenol, a receptor activating factor, the EC50 would be increased from 1.38 x 10(-6) mol/L to 6.25 x 10(-6) mol/L, P < 0.05. This effect of PAF could also be inhibited by ginkgolides (P < 0.05).

CONCLUSION

Ginkgolides is a promising PAF antagonist, and might be used in treating bronchial asthma.

[Ginkgolides antagonizing some effects of platelet-activating factor in vitro]

The mixture of platelet-activating factor (PAF) and platelets produced significant contraction of guinea pigs' bronchus, while the contraction induced by PAF alone was mild relatively, the IC50 were 6.14 x 10(-7) mol/L and 6.32 x 10(-4) mol/L respectively. There was significant difference between these two groups (P < 0.05). When the platelets were pre-incubated with ginkgolides for 10 minutes in Tris-Tyrode's buffered saline, effects of the PAF and platelets mixture were significantly inhibited (P < 0.01). Exposure of guinea pigs' bronchus to PAF in vitro resulted in a loss of beta-adrenergic receptors and responses to isoproterenol, and this effect of PAF was prevented by prior incubation of the guinea pigs' bronchus with ginkgolides (P < 0.05). The results showed ginkgolides were a potent PAF antagonist.

[Investigation of treating steroids dependent asthmatic patients with kidney-tonifying herbs and high dose beclomethasone dipropionate aerosol]

The steroids dependent asthmatic(SDA) patients need prolonged oral steroids administration. Because of the significant adverse effects with long-term use of steroids, especially the damage of the hypothalamus-pituitary-adrenocortical(HPA) axis, long-term steroids administration should be avoided or withdrawn gradually. Many modes of withdrawing the oral steroids have be used. But, the results were not satisfactory. So far, recently, investigations have revealed that high dose corticosteroids inhalation, such as beclomethasone dipropionate (BDP), could provide an effective alternative; they were delivered locally in the airway and had minimal systemic absorption as well as side effects. On the other hand, it has been shown that the Kidney-Tonifying herbs (KTH) exert protective effect on the adrenocortical cells of the SDA patients by suppressing the exogenous steroids and could regulate the disorders in different levels on HPA axis in the patients. In order to provide the more effective alternative therapy for the patients, 30 SDA patients replaced their oral steroids with KTH and high dose BDP (1500 micrograms/day) inhalation were investigated. The changes of clinical features, pulmonary function and the Synacthen Test were followed up. The results showed that about 70% of the patients replaced their oral steroids successfully with the new therapy, the clinical features were improved in 16% of the patients and the ineffective rate was only 6.6%; the results also revealed that, after replacement, the pulmonary function of the patients were improved (P < 0.05); the data of Synacthen Test indicated, after alternative therapy for 3-6 months, the damaged reserve power and secretive ability of adrenal cortex of the patients were also improved partially (P < 0.001).

[The investigation on 100 bronchial asthma and asthmatic bronchitis cases treated with high dose beclomethasone dipropionate aerosol]

100 cases, of which sixty four bronchial asthma patients and forty two asthmatic bronchitis patients sufficiently severe to be treated with inhaled corticosteroids, were investigated. All were treated with high dose beclomethasone dipropionate (BDP) inhaler aerosol (1500-2000 micrograms/day) for three months. The results showed the total effective rate was 98.4% in bronchial asthma patients and 62.5% in asthmatic bronchitis patients. The pulmonary functions and bronchial hyperresponsiveness of most bronchial asthmatic patients were improved significantly after 1-2 weeks treatment. It is recommendable to treat the oral cortisone-depending patients with BDP inhaler. After 3 months treatment, the adrenocortical secretive ability and reserve power of the patients could be slightly damaged. The investigation also showed 8 percent subjects complained of dysphonia and 25 percent suffered from oropharyngeal candidiasis. Finally, the asthmatic relapse rate was high after cessation of the therapy.

[Treatment of 106 chronic obstructive pulmonary diseases with shou er kang pill and high dose beclomethasone dipropionate aerosol]

106 chronic obstructive pulmonary disease (COPD) cases were divided into two groups, 53 cases treated with Shou Er Kang (SEK) pill (Kidney-reinforcing regimen) and high dose beclomethasone dipropionate inhaler, and 53 cases in the control group with high dose beclomethasone dipropionate aerosol alone. 64 patients were suffering from bronchial asthma and 42 patients from asthmatic bronchitis, sufficiently severe to be treated with inhaled corticosteroids. The results showed that the total effective rate was 100% and 96.9% in asthmatic patients of both groups; the total effective rates for asthmatic bronchitis patients were 85.7% in the SEK group and 52.4% in the control group. The Synacthen test showed that after the treatment, the adrenal cortex reserve power and secretive ability of the SEK group not only was intact but also improved markedly under high dose exogenous steroids. The adrenocortical secretive ability and reserve power of the control group were damaged with the inhalation of the newer steroids. The difference between the two groups was very significant (P less than 0.001); the relapse rate in the SEK group was 26.9%, but 40% in the control group. The results suggested that there were some occult disorders in COPD patients, especially asthmatic bronchitis patients at different levels on hypothalamus-pituitary-adrenocortical axis.

Experimental study on relative biological effectiveness of tritium and risk estimates of genetic damage

The relative biological effectiveness (RBE) and the genetic effect of tritium internal exposure compared with those of Co-60 gamma rays external exposure are studied in mice. Two different irradiation models are used: 1) irradiation by single intake of tritium, or by Co-60 gamma rays external exposure with gradually decreasing doses simulating the exponential decreasing function of tritium in the mouse body; 2) irradiation by continual intake of tritium, or by Co-60 gamma rays external exposure at constant dose rates. The biological effective end points observed in this study are dominant lethal mutations, dominant skeleton mutations, survival rates of primary oocytes and spermatogonia and chromosome aberrations in spermatocytes. The experimental results show that the RBE values of tritium would be 2.24 to 2.99 in the dose range of 0.02-0.06 Gy/day. The risk estimates of genetic damage from dominant skeleton mutations are 10959/10(6). Gy for tritium beta rays and 3605/10(6). Gy for Co-60 gamma rays.