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An electric-field mechanism has been developed to explain the oxide-assisted growth of silicon nanowires. This mechanism assumes a strong electric field at the tip of silicon nanowires. Most of the SiO molecules would be attracted by this electric field and then land on the nanowire tip. Thus, the silicon nanowire growth is restricted at the tip only. The maximum electric field that could possibly exist has been estimated from the field emission data. The probability of SiO vapor landing on the nanowire tip is calculated for a wide range of conditions. The result shows that for a sufficiently strong electric field, all SiO vapor would land on the nanowire tip. This attractive force to the nanowire tip is even more pronounced if the SiO vapor first condenses to form a larger cluster. All these calculation results suggest that this electric-field mechanism is possible. [ABSTRACT FROM AUTHOR]

Objectives The aims of this study were to identify the active ingredients from P ortulaca oleracea L. ( PO) that could provide synergism with antibiotics against methicillin-resistant S taphylococcus aureus ( MRSA) and their possible mechanisms of resistance inhibition. Methods High-speed counter-current chromatography ( HSCCC) coupled with gas chromatography-mass spectrometry and a panel of laboratory MRSA strains were used for checkerboard and efflux inhibitory assays. Key findings Linoleic and oleic acids were identified from HSCCC fraction 18 of PO with synergistic antibacterial activity when combined with erythromycin against RN4220/ pUL5054. Ethidium bromide efflux inhibitory studies revealed that linoleic and oleic acids may interfere the activity of MsrA pump. By comparing among a panel of linoleic and oleic acids analogues, unsaturated fatty acids in salt form with cis configuration and an increase in number of double bonds were found to further increase the antibacterial activity when used alone or in combination with antibiotics. Conclusion This study reported for the first time that two active ingredients, namely linoleic and oleic acids, were identified from PO with synergistic antibacterial activity when combined with erythromycin against MRSA RN4220/ pUL5054 and possibly act by inhibiting the efflux pumps of the bacteria cells. [ABSTRACT FROM AUTHOR]

Antiresorptive drugs, alendronate and raloxifene, are effective in lowering bone mineral density (BMD) loss in postmenopausal women. However, long-term treatment may be associated with serious side effects. Our research group has recently discovered that a Chinese herbal formula, ELP, could significantly reduce BMD loss in animal and human studies. Therefore, the present study aimed to investigate the potential synergistic bone-protective effects of different herb-drug combinations using ovariectomized rats. To assess the efficacy of different combinations, the total BMD was monitored biweekly in the 8-week course of daily oral treatment. Bone microarchitecture, bone strength, and deoxypyridinoline level were also determined after 8 weeks. From our results, coadministration of ELP and raloxifene increased the total tibial BMD by 5.26% (2.5 mg/kg/day of raloxifene; P = 0.014) and 5.94% (0.25 mg/kg/day of raloxifene; P = 0.026) when compared with the respective dosage groups with raloxifene alone. Similar synergistic effects were also observed in BMD increase at distal femur (0.25 mg/kg/day; P = 0.001) and reduction in urinary deoxypyridinoline crosslink excretion (2.5 and 0.25 mg/kg/day; both P = 0.02). However, such interactions could not be observed in all alendronate-treated groups. Our data provide first evidence that ELP could synergistically enhance the therapeutic effects of raloxifene, so that the clinical dosage of raloxifene could be reduced.