Improved Osteointegration of Ti-6Al-4V-implants of Different Surface Texture by the Use of Bone Morphogenetic Protein-3 (BMP-3)

1Introduction Withregardstolong termstabilityandimplantfixa tionthedevelopmentofnon cementedimplantswhichfos tertheirownosteointegrationbywayofreleasingosteoin duciveproteinsisofgreatimportance.Thus,thedevelop mentofsuccessfulcombinationsofosteoinductivef…     

Fast time constant estimation for plunge grinding process control

The time constant of a grinding control system indicates the speed of response to a control command and reflects variations of the wheel condition. In order to allow correct and continuous control adjustment, fast in-process estimation of the parameter is necessary. The significance of the grinding system time constant is discussed and the control system for the plunge grinding process described. An algorithm for fast time constant estimation is presented for adaptive control of the grinding process. The algorithm is useful for geometry-based grinding control systems where a workpiece size sensor is used and multiple control tasks are implemented. Experimental testing of the algorithm is explained and comparison between results from grinding and those from analysis shows that the proposed algorithm is sufficiently accurate and effective for adaptive control of the plunge grinding process.     

Experiences of algae in UK waters: a treatment perspective

Algae blooms are a seasonal problem in UK waters and during these periods interferences with treatment plants are reported. This paper presents an analysis of data from 2000 to 2005 demonstrating UK experiences of algae at water treatment works. Cell populations are lower than those reported in the 1970s and 1980s, but reach levels that adversely affect treatment processes. Diatoms and cyanobacteria dominate in spring and autumn respectively. A treatment works including pre-oxidation, coagulation, flotation and filtration removes on average 96% of influent cells, while rapid gravity filters alone remove 63–75%. Cells present in the filtrate are typically either unicellular, micro-algae, or flagellated algae. filter blockages in the spring and autumn are caused by large cells of complex morphology, including the diatoms Melosira and Asterionella . Overall, since the 1980s the key issue with respect to algae treatment has changed from one of treatability to that of process optimisation and economics.     

Synthesis and study of new radial organic/inorganic hybrid epoxides

A new approach to the synthesis of reactive organic/inorganic hybrid molecules was developed. Alternating hydrocarbon and siloxane segments were introduced into the arms of radial oligomers using hydrosilation chemistry. Cycloaliphatic and glycidyl epoxy‐terminal systems with bisphenol A‐based aromatic hydrocarbon cores and siloxane units derived from 1,1,3,3‐tetramethyldisiloxane were synthesized and fully characterized (molecules 7 and 6 , respectively). The cationic UV and thermal curing behavior of these two new radial hybrid epoxies was investigated using photo‐ and thermal‐ differential scanning calorimetry. Hybrid cycloaliphatic epoxy 7 exhibited good UV curing kinetics and photopolymerized to high conversion. The glycidyl analog 6 exhibited poor UV curing kinetics, but was readily cured using 2‐ethyl‐4‐methylimidazole as a nucleophilic curing agent. Both hybrid epoxysiloxanes exhibited extensive thermal cationic cure. The physical properties of cured films of the two new radial epoxysiloxanes were studied and compared with various commercially available hydrocarbon and siloxane benchmark materials. The cured systems exhibited lower moisture uptake and better thermal stability than most hydrocarbon epoxies examined. Several visually compatible blends of the new hybrid molecules with common hydrocarbon resins were identified, and in general organic compatibility was found to be intermediate among selected siloxane‐containing benchmarks. Molecules 6 and 7 represent progress towards the goal of synthesizing highly functional organic/inorganic hybrid molecules which combine the best attributes of both hydrocarbon epoxides and siloxane materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Simulating the Effect of Sulfate Addition on Methylmercury Output from a Wetland

The watershed analysis risk management framework (WARMF) model was applied to Wetland S6 of the Marcell Experimental Forest, using the data from a field experiment, conducted to investigate the effect of sulfate additions on mercury methylation in the wetland. The wetland was modeled as interconnected land catchments. Actual meteorology data and mercury and sulfate concentrations of precipitation were input to the model. To simulate the sulfate sprinkling, the experimental section of the bog was irrigated with sulfate water on the actual dates of sulfate additions. The model simulated wetland outflows that matched the measured outflows with an R-square of 0.856. WARMF also simulated other phenomena observed in the experiment: higher sulfate and MeHg levels at the wetland outlet after every sulfate addition, and higher sulfate and MeHg levels in the pore water of the bog after only the May addition, not the July and September additions. According to WARMF, the low groundwater table in May allowed the sprinkled sulfate to percolate to the soil stratum 10–30 cm below the ground level of the bog, where the pore water was sampled. In July and September, the sulfate could not reach that zone because the percolation was blocked by high groundwater tables. The sampled soil stratum was not the site of methylation that contributed MeHg to the wetland outlet. The saturated zone of the top 10 cm of bog was the site that produced MeHg, which was flushed to the outlet after all sulfate additions. WARMF predicted that quadrupling the sulfate deposition would increase the MeHg output by 216%, which might become lower with more data and better model calibration.     

Effects of backwashing on the prosobranch snail Potamopyrgus jenkinsi Smith in granular activated carbon (GAC) adsorbers

Granular activated carbon (GAC) adsorbers are often the penultimate stage of surface water treatment and provide ideal habitats for invertebrates. Proliferation of chlorine-resistant invertebrates in GAC adsorbers may lead to their efflux into distribution systems, possibly resulting in contamination of customers' tap water. GAC adsorber sampling and laboratory experiments were undertaken to determine the effects of routine backwashing on GAC adsorber populations of the chlorine-resistant snail Potamopyrgus jenkinsi at a water treatment works. GAC adsorber sampling results suggested that routine backwashing altered the spatial distribution of snails, but not their overall abundance. In small-scale glass columns 40-50% of the smallest (0.3-0.6 mm shell height) juvenile snails were removed by a GAC backwash bed expansion of 30-40%; however, bed expansions of greater than 20% were not possible in the GAC adsorbers.     

Aptamer-conjugated nanoparticles for selective collection and detection of cancer cells

We have developed a method for the rapid collection and detection of leukemia cells using a novel two-nanoparticle assay with aptamers as the molecular recognition element. An aptamer sequence was selected using a cell-based SELEX strategy in our laboratory for CCRF-CEM acute leukemia cells that, when applied in this method, allows for specific recognition of the cells from complex mixtures including whole blood samples. Aptamer-modified magnetic nanoparticles were used for target cell extraction, while aptamer-modified fluorescent nanoparticles were simultaneously added for sensitive cell detection. Combining two types of nanoparticles allows for rapid, selective, and sensitive detection not possible by using either particle alone. Fluorescent nanoparticles amplify the signal intensity corresponding to a single aptamer binding event, resulting in improved sensitivity over methods using individual dye-labeled probes. In addition, aptamer-modified magnetic nanoparticles allow for rapid extraction of target cells not possible with other separation methods. Fluorescent imaging and flow cytometry were used for cellular detection to demonstrate the potential application of this method for medical diagnostics.     

Corrosion characterization of durable silver coatings by electrochemical impedance spectroscopy and accelerated environmental testing

Highly reflective front-surface silver mirrors are needed for many optical applications. While various protective dielectric coating schemes have been developed, the long-term durability of Ag mirrors is still of great concern in the optics community for a variety of applications under harsh environments. The corrosion protection behavior of a SiNx-coated silver-mirror coating scheme was tested with electrochemical impedance spectroscopy (EIS) and accelerated environmental testing, including humidity and salt fog tests. The EIS data obtained were fitted with different equivalent circuit models. The results suggested that the 100A thick SiNx coating produced by rf magnetron sputtering was porous and acted as a leaky capacitor on the Ag film, whereas the addition of a NiCrNx interlayer as thin as 3A between SiNx and Ag films resulted in a much denser SiNx coating with a low-frequency impedance value of 2 orders of magnitude higher than that without the interlayer. Humidity and salt fog testing of different silver coatings showed similar results. The 100A SiNx/3A-NiCrNx/Ag coating exhibited excellent corrosion resistance against the corrosive environments used in this study.     

城市艺坊

城市艺坊是一个集建筑、园景、公共艺术及奥运元素于一身的大型国际性公共艺术公园,位于香港沙田大会堂对面、商业发展项目及公众文化设施之间,其目的是美化公共空间,推动艺术及文化。     

Electrostatic protein immobilization using charged polyacrylamide gels and cationic detergent microfluidic Western blotting

We report a novel protein immobilization matrix for fully integrated microfluidic Western blotting (WB). The electrostatic immobilization gel (EIG) enables immobilization of all proteins sized using cetyl trimethylammonium bromide polyacrylamide gel electrophoresis (CTAB-PAGE), for subsequent electrophoretic probing with detection affinity reagents (e.g., labeled antibodies). The "pan-analyte" capture strategy introduced here uses polyacrylamide gel grafted with concentrated point charges (zwitterionic macromolecules), in contrast to existing microfluidic WB strategies that rely on a sandwich immunoassay format for analyte immobilization and detection. Sandwich approaches limit analyte immobilization to capture of only a priori known targets. A charge interaction mechanism study supports the hypothesis that electrostatic interaction plays a major role in analyte immobilization on the EIG. We note that protein capture efficiency depends on both the concentration of copolymerized charges and ionic strength of the gel buffer. We demonstrate pan-analyte immobilization of sized CTAB-laden model proteins (protein G, ovalbumin, bovine serum albumin, β-galactosidase, lactoferrin) on the EIG with initial capture efficiencies ranging from 21 to 100%. Target proteins fixed on the EIG (protein G, lactoferrin) are detected using antibody probes with signal-to-noise ratios of 34 to 275. The approach advances protein immunoblotting performance through 200× reduction on sample consumption, 12× reduction in assay duration, and automated assay operation, compared to slab-gel WB. Using the microfluidic WB assay, assessment of lactoferrin in human tear fluid is demonstrated with a goal of advancing toward nonbiopsy-based diagnosis of Sj?gren's Syndrome, an autoimmune disease.