Characterization of metal aerosols in PM10 from urban, industrial, and Asian Dust sources.

Metallic elements (As, Be, Ca, Cd, Co, Cr, Fe, K, Mn, Ni, Pb, Sb, Se, and Zn) in PM10 aerosols were determined at urban and industrial sites, which are affected by traffic and residential sources, metallurgical activity, and petrochemical and steel works. The effect of the long-range transported Asian Dust on the metal content of aerosols was also examined. At the urban sampling site, concentrations of As, Cd, Pb, Se, and Zn were assigned to road traffic and combustion sources, Ca and Fe to soil dust sources from long-range transported Asian Dusts, and Cr and Ni to metallurgical sources transported from the nearby industrial complex, based on Principal Component Analysis (PCA).

Removal of cetyltrimethylammonium bromide to enhance the biocompatibility of Au nanorods synthesized by a modified seed mediated growth process.

Previously, we reported the synthesis of stable gold nanorods with higher aspect ratio (approximately 15-20) and more enhanced uniformity by a modified seed mediated growth approach using a binary surfactant system consisting of CTAB and Pluronic F-127. For the in vivo application of gold nanorods, the removal of CTABs that are strongly bound on prepared Au nanorods is necessary due to their cytotoxicity. Use of heat or acid at various conditions was performed to achieve the complete removal of CTAB from the synthesized Au nanorods while maintaining their stability.

Change of viscoelastic property and morphology of fibrin affected by antithrombin III and heparin: QCM-Z and AFM study.

Viscoelastic property and morphology of fibrin, which is caused by the enzymatic action of thrombin on fibrinogen, was studied quantitatively as a function of antithrombin III (AT) and heparin concentration by adding fibrinogen, heparin, AT, and thrombin, sequentially. A quartz crystal microbalance with impedance analysis (QCM-Z) was used to detect the change of viscoelastic properties as well as the thickness of adsorbed layer during fibrin formation process, while AFM was used to characterize the surface morphology of fibrin layer under the influence of two known anticoagulants. By the addition of fibrinogen initially, a rigid and thin fibrinogen layer with rather smooth surface morphology was formed on the substrate.

A novel germ cell-specific protein, SHIP1, forms a complex with chromatin remodeling activity during spermatogenesis.

To determine the mechanisms of spermatogenesis, it is essential to identify and characterize germ cell-specific genes. Here we describe a protein encoded by a novel germ cell-specific gene, Mm.290718/ZFP541, identified from the mouse spermatocyte UniGene library.

Characterization of eight novel proteins with male germ cell-specific expression in mouse.

Background: Spermatogenesis and fertilization are highly unique processes. Discovery and characterization of germ cell-specific genes are important for the understanding of these reproductive processes. We investigated eight proteins encoded by novel spermatogenic cell-specific genes previously identified from the mouse round spermatid UniGene library.

Trapping of a micro-bubble by non-paraxial Gaussian beam: computation using the FDTD method.

Optical forces on a micro-bubble were computed using the Finite Difference Time Domain method. Non-paraxial Gaussian beam equation was used to represent the incident laser with high numerical aperture, common in optical tweezers. The electromagnetic field distribution around a micro-bubble was computed using FDTD method and the electromagnetic stress tensor on the surface of a micro-bubble was used to compute the optical forces.

Structural analysis of immunotherapeutic peptides for autoimmune Myasthenia gravis.

Myasthenia gravis (MG) and its animal model, experimental MG (EAMG), are autoimmune disorders in which major pathogenic antibodies are directed against the main immunogenic region (MIR) of the nicotinic acetylcholine receptor (nAChR). In an earlier attempt to develop peptide mimotopes capable of preventing the anti-MIR-mediated pathogenicity, the peptide Pep.1 was initially identified from phage display, and subsequently, Cyclic extended Pep.

Thermal gellation and photo-polymerization of di-acrylated Pluronic F 127.

Thermal gellation and photo-cross-linking of di-acrylated Pluronic PF 127 (DA-PF 127) were characterized. First, thermo-hysteresis of Pluronic F 127 (PF 127) solution was characterized. Upon heating, thermal gellation was observed at higher temperature with faster heating rate, whereas upon cooling, the re-melting was rather insensitive to cooling rate.

pH-sensitive polymer nanospheres for use as a potential drug delivery vehicle.

We report the development and characterization of pH-sensitive poly(2-tetrahydropyranyl methacrylate) [poly(THPMA)] nanospheres and demonstrate their feasibility as an effective drug delivery vehicle. Poly(THPMA) nanospheres were prepared using either the double emulsion or single emulsion method for the encapsulation of, respectively, water soluble (rhodamine B) or organic soluble (paclitaxel) payloads. The resulting nanospheres showed pH-dependent dissolution behavior, resulting in significant morphologic changes and loss of nanoparticle mass under mild acidic conditions (pH 5.

Dual functional, polymeric self-assembled monolayers as a facile platform for construction of patterns of biomolecules.

We report a facile approach to the construction of patterns of biomolecules based on polymeric self-assembled monolayers (pSAMs) that possess dual functions: "bio-reactive (post-functionalizable)" and "bio-inert (anti-biofouling)" properties. To prepare pSAMs on Si/SiO2 wafers were synthesized new random copolymers by radical polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA), 3-(trimethoxysilyl)propyl methacrylate (TMSMA), and N-acryloxysuccinimide (NAS), and referred to as poly(TMSMA-r-PEGMA-r-NAS). Poly(TMSMA-r-PEGMA-r-NAS) was designed to play triple roles: "surface-reactive", "bio-reactive", and "bio-inert" ones.

Thermally cross-linked superparamagnetic iron oxide nanoparticles: synthesis and application as a dual imaging probe for cancer in vivo.

We report the fabrication and characterization of thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION) and their application to the dual imaging of cancer in vivo. Unlike dextran-coated cross-linked iron oxide nanoparticles, which are prepared by a chemical cross-linking method, TCL-SPION are prepared by a simple, thermal cross-linking method using a Si-OH-containing copolymer. The copolymer, poly(3-(trimethoxysilyl)propyl methacrylate-r-PEG methyl ether methacrylate-r-N-acryloxysuccinimide), was synthesized by radical polymerization and used as a coating material for as-synthesized magnetite (Fe3O4) SPION.

Differentially expressed genes implicated in unexplained recurrent spontaneous abortion.

Recurrent spontaneous abortion occurs in approximately 3% of women with diagnosed pregnancies. The etiology in approximately 40% of recurrent spontaneous abortion is unexplained. To elucidate unexplained recurrent spontaneous abortion at the molecular level, we systemically identified differentially expressed genes during implantation window period in unexplained recurrent spontaneous abortion and characterized their functions in a human endometrial cell line.

Cytokine-like 1 (Cytl1) regulates the chondrogenesis of mesenchymal cells.

To identify novel molecules regulating chondrogenesis and cartilage development, we screened a cartilage-specific expressed sequence tag data base. Cytokine-like 1 (Cytl1), a possible cytokine candidate with unknown function that was originally identified in bone marrow-derived CD34-positive cells, was selected for functional characterization. In view of the initial observation that Cytl1 is predominantly expressed in chondrocytes and cartilage, we investigated its possible role in chondrogenesis and hypertrophic maturation of chondrocytes.

Enhanced bone regeneration with BMP-2 loaded functional nanoparticle-hydrogel complex.

As an efficient sustained release system of BMP-2, a functional nanoparticle-hydrogel complex, composed of heparin-functionalized nanoparticles and fibrin gel, was developed and used as a bone graft. In vivo bone formation was evaluated by soft X-ray, histology, alkaline phosphatase (ALP) activity, immunostaining, and mineral content analysis, based on the rat calvarial critical size defect model. Significantly improved and effective bone regeneration was achieved with the recombinant BMP-2 (4 mug) loaded nanoparticle-fibrin gel complex, as compared to bare fibrin gel, the nanoparticle-fibrin gel complex without BMP-2, or even the BMP-2 loaded fibrin gel.

Antibiofouling polymer-coated gold nanoparticles as a contrast agent for in vivo X-ray computed tomography imaging.

Current computed tomography (CT) contrast agents such as iodine-based compounds have several limitations, including short imaging times due to rapid renal clearance, renal toxicity, and vascular permeation. Here, we describe a new CT contrast agent based on gold nanoparticles (GNPs) that overcomes these limitations. Because gold has a higher atomic number and X-ray absorption coefficient than iodine, we expected that GNPs can be used as CT contrast agents.

Formation of a novel heparin-based hydrogel in the presence of heparin-binding biomolecules.

An injectable, heparin-based hydrogel system with the potential to be gelled with cells was developed. First, heparin was modified to have thiol groups by the modification of carboxylic groups of heparin with cysteamine using carbodiimide chemistry. Thiol functionalization of heparin carboxylic groups was controlled from 10% to 60% of the available COOH groups, and the retained bioactivity of the modified heparin, characterized by its binding affinity to antithrombin III, decreased with increasing functionalization.

Formulation and in vitro characterization of an in situ gelable, photo-polymerizable Pluronic hydrogel suitable for injection.

Utilizing the existence of a sufficiently long induction period during photo-polymerization, defined as the time required to initiate macroscopic gelation after UV irradiation, we propose a new injection method of making a photo-polymerized hydrogel made of thermo-sensitive di-acrylated Pluronic F 127 (DA-PF 127). First, the photo-polymerization of DA-PF 127 solution at the molecular level is initiated by UV irradiation, and this solution is injected into a target site by macroscopic gelation before it becomes viscous. This method can overcome the problems of the existing methods to make an injectable and stable hydrogel by photo-polymerization, reducing the potential damage to normal tissue around the injection site due to direct UV exposure, and the requirement of special equipment for UV crosslinking after injection.

Regulation of type II collagen expression by histone deacetylase in articular chondrocytes.

Histone deacetylase (HDAC) regulates various cellular processes by modulating gene expression. Here, we investigated the role of HDAC in the expression of type II collagen, a marker of differentiated chondrocytes. We found that HDAC activity in primary articular chondrocytes decreases during dedifferentiation induced by serial monolayer culture and that the activity recovered during redifferentiation induced by three-dimensional culture in a cell pellet.

Hydrophobic interface between two regulators of K+ conductance domains critical for calcium-dependent activation of large conductance Ca2+-activated K+ channels.

It has been suggested that the large conductance Ca(2)+-activated K(+) channel contains one or more domains known as regulators of K(+) conductance (RCK) in its cytosolic C terminus. Here, we show that the second RCK domain (RCK2) is functionally important and that it forms a heterodimer with RCK1 via a hydrophobic interface. Mutant channels lacking RCK2 are nonfunctional despite their tetramerization and surface expression.