Implementation of a simplified method for actuation of ferrofluids

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Magnetic actuation of ferrofluids is an emergent field that will open up new possibilities in various fields of engineering. The quality and topology of the magnetic field that is being utilized in such systems is determinant in terms of flow properties, flow rates and overall efficiency. Determining the optimal magnetic field topology to achieve the desired results, and determining the methods by which these magnetic fields are to be generated are central problems of obtaining the desired flow. A healthy comparison of various magnetic field topologies requires a varied set of examples from the most simplified to most sophisticated. Such comparisons are necessary to have a well grounded starting point. This study focuses on a particular pump design that employs a simplified magnetic field topology to obtain ferrofluid flow. The results of this paper such as flow and pressure difference are intended to form a baseline for future reference.Sabancı University Internal Research Grant, no: IACF09-0064

Estimating Evapotranspiration from Satellite Using Easily Obtainable Variables: A Case Study over the Southern Great Plains, U.S.A.

Evapotranspiration (ET) is a critical component of the Earth's water budget, a critical modulator of land-atmosphere (L-A) interactions, and also plays a crucial role in managing the Earth's energy balance. In this study, the feasibility of generating spatially-continuous daily evaporative fraction (EF) and ET from minimal remotely-sensed and meteorological inputs in a trapezoidal framework is demonstrated. A total of four variables, Normalized Difference Vegetation Index (NDVI), Land surface temperature (T(sub s)), gridded daily average temperature (T(sub a)) and elevation (z) are required to estimate EF. Then, ET can be estimated with the available soil heat flux (G) and net radiation (Rn) data. Firstly, the crucial model variable, T(sub s)-T(sub a), is examined how well it characterizes the variation in EF using in situ data recorded at two eddy correlation flux towers in Southern Great Plains, U.S.A. in 2011. Next, accuracy of satellite-based T(sub s) are compared to ground-based T(sub s). Finally, EF and ET estimates are validated. The results reveal that the model performed satisfactorily in modeling EF and ET variation at winter wheat and deciduous forest during the high evaporative months. Even though the model works best with the observed MODIS-T(sub s) as opposed to temporally interpolated T(sub s), results obtained from interpolated T(sub s) are able to close the gaps with reasonable accuracy. Due to the fact that T(sub s)-T(sub a), is not a good indicator of EF outside the growing season when deciduous forest is dormant, potential improvements to the model are proposed to improve accuracy in EF and ET estimates at the expense of adding more variables

In Situ Synthesis of Polymer/Clay Nanocomposites by Type II Photoinitiated Free Radical Polymerization

Cataloged from PDF version of article.A new synthetic route for the preparation of poly(methyl methacrylate)/montmorillonite (PMMA/MMT) nanocomposites was reported. In this method, first 4-(dimethylamino)benzoate group was incorporated into silicate layers of clay by esterification reaction and used to produce PMMA/MMT nanocomposites by in situ Type II photoinitiated free radical polymerization. In situ photopolymerization of methyl methacrylate through into the silicate layers by either visible or UV light irradiation leads to PMMA/MMT nanocomposites. Copyright © 2011 Wiley Periodicals, Inc

Novel monoclonal antibodies detect Smad-Interacting Protein 1 (SIP1) in the cytoplasm of human cells from multiple tumor tissue arrays

Cataloged from PDF version of article.Smad-interacting protein 1 (SIP1, also known as ZEB2) represses the transcription of E-cadherin and mediates epithelial-mesenchymal transition in development and tumor metastasis. Due to the lack of human SIP1-specific antibodies, its expression in human tumor tissues has not been studied in detail by immunohistochemistry. Hence, we generated two anti-SIP1 monoclonal antibodies, clones 1C6 and 6E5, with IgG1 and IgG2a isotypes, respectively. The specificity of these antibodies was shown by Western blotting studies using siRNA mediated downregulation of SIP1 and ZEB1 in a human osteosarcoma cell line. In the same context, we also compared them with 5 commercially available SIP1 antibodies. Antibody specificity was further verified in an inducible cell line system by immunofluorescence. By using both antibodies, we evaluated the tissue expression of SIP1 in paraffin-embedded tissue microarrays consisting of 22 normal and 101 tumoral tissues of kidney, colon, stomach, lung, esophagus, uterus, rectum, breast and liver. Interestingly, SIP1 predominantly displayed a cytoplasmic expression, while the nuclear localization of SIP1 was observed in only 6 cases. Strong expression of SIP1 was found in distal tubules of kidney, glandular epithelial cells of stomach and hepatocytes, implicating a co-expression of SIP1 and E-cadherin. Squamous epithelium of the esophagus and surface epithelium of colon and rectum were stained with moderate to weak intensity. Normal uterus, breast and lung tissues remained completely negative. By comparison with their normal tissues, we observed SIP1 overexpression in cancers of the kidney, breast, lung and uterus. However, SIP1 expression was found to be downregulated in tumors from colon, rectum, esophagus, liver and stomach tissues. Finally we did nuclear/cytoplasmic fractionation in 3 carcinoma cell lines and detected SIP1 in both fractions, nucleus being the dominant one. To our best knowledge, this is the first comprehensive immunohistochemical study of the expression of SIP1 in a series of human cancers. Our finding that SIP1 is not exclusively localized to nucleus suggests that the subcellular localization of SIP1 is regulated in normal and tumor tissues. These novel monoclonal antibodies may help elucidate the role of SIP1 in tumor development. © 2010 Elsevier Inc

Sulfatide mediates attachment of Pseudomonas aeruginosa to human pharyngeal epithelial cells

Pseudomonas aeruginosa infections are particularly common in people with cystic fibrosis and despite regular treatment with antibiotics, lung damage due to chronic infection with P. aeruginosa remains the major cause of death in those patients. In order to initiate an infection, P. aeruginosa needs contact with the respiratory epithelial surface and by means of its adhesins i.e., fimbria, hemagglutinins,etc., it recognizes and adheres to the corresponding epithelial receptors. We treated P. aeruginosa strains isolated from sputum of cystic fibrosis patients with several glycolipids such as sulfatide, sulfated ganglioside mixture (GM1a, GD1b, GT1b), asialo-GM1 and galactocerebrosides to determine their effect on attachment with pharyngeal epithelial cells. Sulfated ganglioside mixture and sulfatide inhibited the attachment of P. aeruginosa significantly, whereas asialo-GM1, Gal-Cer and sodium sulfite had no effect on attachment inhibition. This finding suggests that sulfated glycoconjugates found in the extracellular matrix, in mucus and on the surface of epithelial cells of human trachea and lung mediates attachment of P. aeruginosa

Polysulfone/Clay Nanocomposites by in situ Photoinduced Crosslinking Polymerization

Cataloged from PDF version of article.PSU/MMT nanocomposites are prepared by dispersing MMT nanolayers in a PSU matrix via in situ photoinduced crosslinking polymerization. Intercalated methacrylate-functionalized MMT and polysulfone dimethacrylate macromonomer are synthesized independently by esterification. In situ photoinduced crosslinking of the intercalated monomer and the PSU macromonomer in the silicate layers leads to nanocomposites that are formed by individually dispersing inorganic silica nanolayers in the polymer matrix. The morphology of the nanocomposites is investigated by XRD and TEM, which suggests the random dispersion of silicate layers in the PSU matrix. TGA results confirm that the thermal stability and char yield of PSU/MMT nanocomposites increases with the increase of clay loading

A Comparison of Satellite Data-Based Drought Indicators in Detecting the 2012 Drought in the Southeastern US

The drought of 2012 in the North America devastated agricultural crops and pastures, further damaging agriculture and livestock industries and leading to great losses in the economy. The drought maps of the United States Drought Monitor (USDM) and various drought monitoring techniques based on the data collected by the satellites orbiting in space such as the Gravity Recovery and Climate Experiment (GRACE) and the Moderate Resolution Imaging Spectroradiometer (MODIS) are inter-compared during the 2012 drought conditions in the southeastern United States. The results indicated that spatial extent of drought reported by USDM were in general agreement with those reported by the MODIS-based drought maps. GRACE-based drought maps suggested that the southeastern US experienced widespread decline in surface and root-zone soil moisture and groundwater resources. Disagreements among all drought indicators were observed over irrigated areas, especially in Lower Mississippi region where agriculture is mainly irrigated. Besides, we demonstrated that time lag of vegetation response to changes in soil moisture and groundwater partly contributed to these disagreements, as well

Synthesis of liquid crystalline graft and block copolymers by sequential cationic and free-radical polymerizations

Abstraet-New graft and block copolymers were synthesized by two procedures, each consisting of a sequence of cationic and free-radical polymerization reactions. One polymer component was a liquid crystalline side-group polymer, with the other polymer component being incorporated in crystalline grafts or in amorphous blocks. The copolymers were microphase-separated and underwent thermal transitions (glass, melting, isotropization) of each individual component

Heparin Mimetic Peptide Nanofibers Promote Angiogenesis

Cataloged from PDF version of article.New blood vessel formation (angiogenesis) is one of the most important processes required for functional tissue formation. Induction of angiogenesis is usually triggered by growth factors released by cells. Glycosaminoglycans (e.g., heparan sulphates) in the extracellular matrix aid in proper functioning of these growth factors. Therefore, exogeneous heparin or growth factors were required for promoting angiogenesis in previous regenerative medicine studies. Here we report for the first time induction of angiogenesis by a synthetic nanofibrous peptide scaffold without the addition of any exogenous growth factors or heparin. We designed and synthesized a self-assembling peptide amphiphile molecule that is functionalized with biologically active groups to mimic heparin. Like heparin, this molecule has the ability to interact with growth factors and effectively enhance their bioactivity. The nanofibers formed by these molecules were shown to form a 3D network mimicking the structural proteins in the extracellular matrix. Because of heparin mimicking capabilities of the peptide nanofibers, angiogenesis was induced without the addition of exogenous growth factors in vitro. Bioactive interactions between the nanofibers and the growth factors enabled robust vascularization in vivo as well. Heparin mimetic peptide nanofibers presented here provide new opportunities for angiogenesis and tissue regeneration by avoiding the use of heparin and exogenous growth factors. The synthetic peptide nanofiber scaffolds enriched with proper chemical functional groups shown in this study can be used to induce various desired physiological responses for tissue regeneration. © 2011 American Chemical Society