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Capillary Action (capillary + action)
Selected AbstractsCharacterization of chitin,metal silicates as binding superdisintegrantsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2009Iyad Rashid Abstract When chitin is used in pharmaceutical formulations, processing of chitin with metal silicates is advantageous, from both an industrial and pharmaceutical perspective, compared to processing using silicon dioxide. Unlike the use of acidic and basic reagents for the industrial preparation of chitin,silica particles, coprecipitation of metal silicates is dependent upon a simple replacement reaction between sodium silicate and metal chlorides. When coprecipitated onto chitin particles, aluminum, magnesium, or calcium silicates result in nonhygroscopic, highly compactable/disintegrable compacts. Disintegration and hardness parameters for coprocessed chitin compacts were investigated and found to be independent of the particle size. Capillary action appears to be the major contributor to both water uptake and the driving force for disintegration of compacts. The good compaction and compression properties shown by the chitin,metal silicates were found to be strongly dependent upon the type of metal silicate coprecipitated onto chitin. In addition, the inherent binding and disintegration abilities of chitin,metal silicates are useful in pharmaceutical applications when poorly compressible and/or highly nonpolar drugs need to be formulated. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4887,4901, 2009 [source] Sphagnum under pressure: towards an ecohydrological approach to examining Sphagnum productivityECOHYDROLOGY, Issue 4 2008D. K. Thompson Abstract The genus Sphagnum is the key peat-forming bryophyte in boreal ecosystems. Relying entirely on passive capillary action for water transport, soil moisture is often the limiting factor in Sphagnum production, and hence peat accumulation. While several hydrological models of peat physics and peatland water movement exist, these models do not readily interface with observations and models of peatland carbon accumulation. A conflict of approaches exists, where hydrological studies primarily utilize variables such as hydraulic head, while ecological models of Sphagnum growth adopt the coarse hydrological variables of water table (WT), volumetric water content (VWC) or gravimetric water content (WC). This review examines the potential of soil pressure head as a measurement to link the hydrological and ecological functioning of Sphagnum in peatlands. The non-vascular structure of Sphagnum mosses and the reliance on external capillary transport of water in the mosses make them an ideal candidate for this approach. The main advantage of pressure head is the ability to mechanistically link plot-scale hydrology to cellular-scale water requirements and carbon exchange. Measurement of pressure head may improve photosynthetic process representation in the next generation of peatland models. Copyright © 2008 John Wiley & Sons, Ltd. [source] Dry-reagent disposable biosensor for visual genotyping of single nucleotide polymorphisms by oligonucleotide ligation reaction: application to pharmacogenetic analysis,HUMAN MUTATION, Issue 8 2008Dimitra K. Toubanaki Abstract Most genotyping methods for known single-nucleotide polymorphisms (SNPs) are based on hybridization with allele-specific probes, oligonucleotide ligation reaction (OLR), primer extension or invasive cleavage. OLR offers superior specificity because it involves two recognition events; namely, the hybridization of an allele-specific probe and a common probe to adjacent positions on target DNA. OLR products can be detected by microtiter well-based colorimetric, time-resolved fluorimetric or chemiluminometric assays, electrophoresis, microarrays, microspheres, and homogeneous fluorimetric or colorimetric assays. We have developed a simple, robust, and low-cost disposable biosensor in dry-reagent format, which allows visual genotyping with no need for instrumentation. The OLR mixture contains a biotinylated common probe and an allele-specific probe with a (dA)20 segment at the 3,-end. OLR products are denatured and applied to the biosensor next to gold nanoparticles that are decorated with oligo(dT) strands. The sensor is immersed in the appropriate buffer and all components migrate by capillary action. The OLR product is captured by immobilized streptavidin at the test zone (TZ) of the sensor and hybridizes with the oligo(dT) strands of the nanoparticles. A characteristic red line is generated due to the accumulation of nanoparticles. The excess nanoparticles are captured by immobilized oligo(dA) at the control zone of the strip, giving a second red line. We have applied successfully the proposed OLR-dipstick assay to the genotyping of four SNPs in the drug-metabolizing enzyme genes CYP2D6 (*3 and *4) and CYP2C19 (*2 and *3). The results were in agreement with direct sequencing. Hum Mutat 0,1,8, 2008. © 2008 Wiley-Liss, Inc. [source] S100A6 expression in fibrohistiocytic lesionsJOURNAL OF CUTANEOUS PATHOLOGY, Issue 5 2001D. R. Fullen Background: S100A6, an S100 calcium-binding protein, has been found in a variety of cutaneous and extracutaneous lesions including: melanocytic nevi, melanoma, some salivary gland and epithelial tumors, and malignant fibrous histiocytoma (MFH). Dermal dendrocytes (DD) in the papillary dermis of skin also express S100A6 protein. We evaluated a variety of cutaneous fibrohistiocytic lesions to determine if the immunophenotype of S100A6 positivity can be expanded to include some or all of these lesions. Methods: Formalin-fixed, paraffin-embedded tissues from fibrous papules (FP, 20), dermatofibromas (DF, 20), dermatofibrosarcoma protuberans (DFSP, 5), atypical fibroxanthomas (AFX, 5), oral fibromas (3), digital fibroma (1), and dermatomyofibroma (1) were evaluated with antibodies to S100A6, S100B, factor XIIIa, and MAC387 using a one-hour capillary action-based immunohistochemical procedure. Results: DD in 20/20 FP, 19/20 DF, and 4/4 fibromas stained positively with anti-S100A6 in a pattern similar to anti-factor XIIIa. No DFSP cases stained with anti-S100A6. Anti-S100A6 showed superior staining to anti-factor XIIIa in 4/5 AFX cases. Conclusions: The immunophenotypes of some fibrohistiocytic lesions can be expanded to include S100A6 protein. With the exception of AFX, the use of anti-S100A6 does not appear to offer added benefit over anti-factor XIIIa in the differential diagnosis of fibrohistiocytic lesions. [source] Raman scattering study of adsorption/desorption of water from single-walled carbon nanotubesJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2005Suresh C. Sharma Abstract We utilized Raman spectroscopy to investigate H2O adsorption in and desorption from single-walled carbon nanotubes (SWCNTs). SWCNT tips were opened by known chemical methods and H2O was inserted into the tubes via capillary action over periods up to 136 h. The wavenumbers in the OH bending region of H2O increase almost exponentially with H2O treatment time. Following H2O adsorption for 136 h, Raman spectra were also measured as a function of heat-treatment temperature. These data lead to 0.07 eV for the H2O desorption energy from SWCNTs. Copyright © 2005 John Wiley & Sons, Ltd. [source] Spectroscopic and theoretical investigation of capillary-induced keto,enol tautomerism of phenacyl benzoylpyridinium-type photoinitiatorsPOLYMER INTERNATIONAL, Issue 4 2007Nihan Yonet Abstract Phenacyl benzoylpyridinium (PBP) salts are effective photoinitiatiors for cationic polymerization. In this study, it is shown that PBP salts are stable in their keto forms, and undergo a reversible keto,enol tautomerization reaction when a capillary action is applied. Spectroscopic and theoretical methods are used to explain the existence of the enol forms in the capillary tube. Copyright © 2006 Society of Chemical Industry Society of Chemical Industry [source] | ||||||||||