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Silver diammine fluoride (SDF) is used as an anticaries agent; however, its mode of action is uncertain, whether chemical, physical, mechanical or antibacterial. As a preliminary study, the effect of SDF on hydroxyapatite (HAp) and gelatin (as a chemically-representative protein) was examined. Methods 2.5 mg HAp powder specimens and 0.5 mL 10% gelatin (Riedel-de Haen) (initially as a sol at ∼37 °C), were mixed with 0.5 mL of 38% SDF (J. Morita), 4% NaF (Sigma) or 40% AgNO3 (Sigma) and tumbled in 1.5 mL polypropylene tubes (Sarstedt) for 48 h at ∼23 °C, in two series: exposed to laboratory lighting, and kept dark at all times. The HAp specimens were separated by centrifugation and decanting, then these and one set of gelatin specimens were dried at 60 °C in situ; a second parallel set of gelatin specimens were dried at ∼23 °C. Each was washed with 1 mL deionized water for 1 min, 3 times. Treated materials were observed, before and after washing, with scanning and transmission electron microscopy (SEM, TEM); energy-dispersive X-ray analysis (EDX), and electron diffraction (ED). Results SDF appeared to produce globular particles of CaF2 on the surface of the HAp, but these disappeared on washing, whilst with AgNO3 yellow cubic crystals of Ag3PO4 formed which were not dissolved on washing, but which darkened, converting gradually to metallic silver, on exposure to light. NaF had no effect on gelatin, whilst with SDF and AgNO3, particles of silver were produced which were resistant to washing. Conclusions Both principal components of tooth tissue react with SDF; the solubility of the putative CaF2 formed weakens the case for it exerting a caries-protective effect. The importance of the persistent silver needs further study.

The publisher regrets that, due to a production error, the key word ‘‘diammine’’ in our recent paper has been ‘corrected’ to the chemically distinct but incorrect ‘diamine’ in both the title and several places in the text, after our proof-reading and corrections. The term ‘amine’ in fact refers to a covalently bound –NH2 group, whilst an ‘ammine’ is a chemical species in which one or more ammonia molecules (NH3) are bound in a coordination complex with a metal ion. As might be imagined, there are profound differences in chemical behaviour and reaction implications, to say nothing of toxicity. The term ‘ammine’ is properly founded, according to Werner (1897)

Friction in actuators of hard disk drives lowers the system gain in low frequency range, which prevents the system positioning accuracy from further improvement. The complexity and multiform of friction make it difficult to obtain a complete friction model. A nonmodel-based robust friction compensation method is introduced, in which the gain decrease in the low frequency domain is compensated by the infinite gain in a bang-bang compensator. The introduced method is simply integrated into the proximate time-optimal servomechanism controller widely used in the current hard disk drives. Simulation results based on a commercial FUJITSU hard disk are presented

With the accelerated development of distributed generation (DG) technology, more and more scholars pay attention to micro-grid (MG). In the early decades, focus was put only on basic technologies. But in recent years, many new methods are being applied in this area, such as artificial intelligence, PSO (particle swarm optimization), interval-based MADM (multi-attribute decision making) using tradeoff analysis. Furthermore, the penetration of DG would influence the existing power market or other former rules of the power system. After reading plenty of publications, in this work we summarize the existed methods already put forward, and discuss some possible solutions that may well settle the following issues. a)power quality and stability; b) protection; c)power balance control policy; d) MG grid programming and economic operation.

This major book presents case studies of ten small country national systems of innovation (NSIs) in Europe and Asia, namely, Denmark, Finland, Hong Kong, Ireland, the Netherlands, Norway, Singapore, South Korea, Sweden and Taiwan. These cases have been carefully selected as examples of success within the context of globalization and as ‘new economies’ where competition is increasingly based on innovation.

Purpose To describe trends in the incidence rates of primary cervical cancer in a geographically defined Chinese population. To link the changes in cervical incidence patterns with efficient screening and targeted educational strategies. Methods Primary liver cancer cases (N = 2594) were diagnosed between 1981 and 2000 and identified by the Tianjin Cancer Registry. Age-adjusted and age-specific incidence rates were examined. Poisson regression was employed to assess the incidence rate trends. All statistical analyses were conducted using the statistical software package SAS version 8.0. Results Crude and age-adjusted incidence rates in the study period were: 6.4/100,000 and 3.8/100,000, respectively. There were remarkable declining trends in incidence rates. The crude and age-adjusted incidence rates declined from 13.8/100,000 and 10.3/100,000 in 1981 to 3.3/100,000 and 2.0/100,000 in 2000. However, the changes in incidence rates were not consistent across age groups. In general, those aged 40 and older had contributed the most observed incidence decline. Contrary to the incidence patterns in people aged 40 and older, incidence rates in those aged 20–39 years and younger increased during the study period. While the results from Poisson regression analyses suggest overall significant trends of declining incidence rates in cervical cancer, there seemed to be a small upward tail toward the end of the study period. Conclusion The findings also indicated two worrisome aspects. First, the incidence rates seemed to increase in younger women; second, there seemed to be a rebound in incidence rates toward the end of the study period. The findings highlight the importance of targeted education toward high-risk population and shed light toward setting up more efficient screening strategies.