Prolonged survival of islet allografts in mice treated with rosmarinic acid and anti-CD154 antibody

Pancreatic islet transplantation can correct the abnormal glucose metabolism of Type 1 diabetes. Although immunosuppressants greatly reduce the acute rejection rate in transplant patients, the long-term side effects can be debilitating. Therefore, researchers are seeking to develop new immunosuppressive regimens that induce maximal levels of immunosuppression with minor side effects. Rosmarinic acid (Ros A) is a secondary metabolite of certain herbs and has multiple biological activities, including anti-inflammatory effects. Here, we have investigated whether treatment of mice with a combination of Ros A and anti-CD154 monoclonal antibody (MR1) improves islet allograft survival in a murine model. After transplantation, the mice were treated with either Ros A, MR1, or both (the "double" treatment). Allograft survival was prolonged in the double-treated animals compared to animals that received only Ros A or MR1. As is the case with the single-treated animals at 15 days after transplantation, the double-treated recipients did not display a significant decrease in the expression of cytokines or the population of activated T cells. Infiltrating CD3(+) T cells were reduced in the MR1- or double therapy relative to control or RosA group. However, at the same time point, double-treated graft showed fewer apoptotic cells and increased expression of insulin and glucagons, compared to the single-treatment groups. Furthermore, long-term (>150 days) allografts that were received with double therapy exhibited larger islet clusters and contained more insulin- and glucagon-positive cells, relative to the MR1-treated grafts. In conclusion, treatment with both Ros A and MR1 has a synergistic effect in murine islet allotransplantation.     

Novel fluorene-based functional 'click polymers' for quasi-solid-state dye-sensitized solar cells

Quasi-solid-state DSSCs in SnO(2):F/quasi-solid-state electrolyte/Pt devices have been fabricated with click polymers for the first time; they show a maximum power conversion efficiency (PCE) of 2.80%.     

Rectangular cymbal arrays for improved ultrasonic transdermal insulin delivery

Circular cymbal ultrasound arrays have been shown to be effective in delivering therapeutic levels of insulin in rats, rabbits, and pigs. To improve delivery efficiency, a rectangular cymbal design was desired in order to achieve a broader spatial intensity field without increasing the size of the device or the spatial-peak temporal-peak intensity (I(SPTP)). With a similar intensity (50 mWcm(2)), the goal was to determine if the 3x1 rectangular cymbal array could perform significantly better than the 3x3 circular array for glucose reduction in hyperglycemic rabbits. Rabbit experiments were performed using three groups: nonsonicated control (n=3), ultrasound exposure using a circular cymbal array (n=3), and ultrasound exposure using a rectangular cymbal array (n=3). Rabbits were anesthetized and a water tight reservoir that held the insulin was fastened on the rabbit's thigh. At the beginning of the experiment and every 15 min for 90 min, the blood glucose level was determined. For comparison between individual rabbits, the absolute level is normalized by subtracting out the baseline in order to arrive at the change in glucose level. For the control group, the normalized glucose level increased (more hyperglycemic) to +80.0+/-28.8 mgdl (mean+/-SEM). Using the circular array, the glucose level decreased to -146.7+/-17.8 mgdl at 90 min. However, using the rectangular cymbal array, the glucose decreased faster and to a level of -200.8+/-5.9 mgdl after 90 min. These results indicated the feasibility of the rectangular cymbal array as an improved device for drug delivery.     

Benzimidazole-based ratiometric fluorescent receptor for selective recognition of acetate

A novel fluorescent receptor bearing benzimidazole moieties as recognition sites was synthesized. The recognition behaviour of the receptor towards various anions has been evaluated in CH₃CN. The receptor showed ratiometric fluorescent changes only with CH₃COO⁻, and it showed no significant response to any of other anions such as Cl⁻, Br⁻, I⁻, , , C₆H₅COO⁻ and .     

Capillary electrophoresis of signaling molecules

The emerging field of quantitative systems biology uses high-throughput bioanalytical measurements to gain a deeper understanding of biological phenomena. With the advent of instrumentation platforms, capillary electrophoresis spans a very wide range of biological applications. This short article focuses on the exploitation of capillary electrophoresis for the systems-level analysis of cell signaling molecules.     

In situ Raman monitoring triazole formation from self-assembled monolayers of 1,4-diethynylbenzene on Ag and Au surfaces via "click" cyclization

We prepared acetylenyl-terminated aromatic self-assembled monolayers (SAMs) of 1,4-diethynylbenzene on silver and gold. After the fabrication of pendent acetylenyl SAMs, the formation of triazoles was performed via Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition "click" chemistry. A density functional theory (DFT) calculation of Raman frequencies showed good agreement with our experimental data to provide evidence of the formation of the triazole molecule. Our results indicated that "click" chemistry could be successfully applied to simple aromatic SAMs proximate (<1 nm) to roughened gold surfaces. The reaction process could be monitored in real time by measuring intensity changes of the nu(CC)(free) band in surface-enhanced Raman scattering (SERS) spectra.     

Measurement of polyamide and polystyrene adhesion with coated-tip atomic force microscopy

This work presents atomic force microscopy (AFM) measurements of adhesion forces between polyamides, polystyrene and AFM tips coated with the same materials. The polymers employed were polyamide 6 (PA6), PA66, PA12 and polystyrene (PS). All adhesion forces between the various unmodified or modified AFM tips and the polymer surfaces were in the range -1.5 to -8 nN. The weakest force was observed for an unmodified AFM tip with a PS surface and the strongest was between a PS-coated tip and PS surface. The results point to both the benefits and drawbacks of coated-tip AFM force-distance measurements. Adhesion forces between the two most dissimilar (PA6-PS and PA66-PS) materials were significantly asymmetric, e.g., the forces were different depending on the relative placement of each polymer on the AFM tip or substrate. Materials with similar chemistry and intermolecular interactions yielded forces in close agreement regardless of placement on tip or substrate. Using experimental forces, we calculated the contact radii via four models: Derjaguin, Muller, and Toporov; Johnson, Kendall, and Roberts; parametric tip-force-distance relation; and a square pyramid-flat surface (SPFS) model developed herein. The SPFS model gave the most reasonable contact tip radius estimate. Hamaker constants calculated from the SPFS model using this radius agreed in both magnitude and trends with experiment and Lifshitz theory.     

Study on threshold behavior of operation voltage in metal filament-based polymer memory

In the metal filament formation-based organic memory, the positive voltage application over the threshold electric field strength (170 MV/m) is necessary for the filament formation in Cu/P3HT/Al device. By the positive voltage application, the copper ions are generated and drifted into polymer layer, which is clearly confirmed by the secondary ion mass spectroscopy. Also, the field strength (100 MV/m) required for the drift process could be independently determined with a new pulse operation method. We could conclude that the threshold field strength of 170 MV/m was determined by the ionization process of copper. Furthermore, the dependence of the positive field strength and the temperature on the memory behavior was studied.