Object-oriented construction of a multigrid electronic-structure code with Fortran 90

We describe the object-oriented implementation of a higher-order finite-difference density-functional code in Fortran 90. Object-oriented models of grid and related objects are constructed and employed for the implementation of an efficient one-way multigrid method we have recently proposed for the density-functional electronic-structure calculations. Detailed analysis of performance and strategy of the one-way multigrid scheme will be presented.Comment: 24 pages, 6 figures, to appear in Comput. Phys. Com

Investigation of cell-based therapies employing microcapsules and microspheres: encapsulation and controlled release

Microencapsulation of therapeutic cells has emerged as a major modality to treat a wide range of diseases through protecting the encapsulated cells. However, in spite of numerous refinements in cell encapsulation during the past decades, the strategy still has not met the requirements for practical relevance. Biocompatible microcapsules (MCs) and -spheres (MSs) were fabricated as advanced drug delivery vehicles for various applications. Novel precision particle fabrication (PPF) was employed to prepare MSs and MCs with controlled size and uniformity which are critical parameters in the release kinetics of drugs including therapeutic proteins and cells. Furthermore, core/shell MCs containing therapeutic cells were investigated for feasibility of employing PPF in practical applications. First, we demonstrated the fabrication of MCs with diameters of 120 – 510 μm by crosslinking core/shell microdrops of highly viscous alginate solutions generated from a coaxial nozzle at a rate of 1,000 drops/sec. Controllability of the microdrop size was validated, optimizing the cell confinement in the core. As practical applications, NIH 3T3 fibroblasts or human and pig islets were encapsulated by PPF, exhibiting no cell protrusion or decrease in their viability. Uniform core/shell MCs co-encapsulating poly (ε-caprolactone) MSs with NIH 3T3 fibroblasts as model anchorage dependent cells (ADCs) were designed to increase the survival of the cells via re-establishment of cell-substrate interactions. The core/shell MCs with the altered intracapsular environment resulted in higher cell survival and proliferation when compared to those without the MSs or the alginate/poly-L-lysine/alginate MCs. This study provides a proof of concept of the co-encapsulation of microspheres with therapeutic ADCs. In order to apply such co-encapsulation strategy to islet xenotransplantation for the treatment of type 1 diabetes, we encapsulated porcine islets together with exenatide-loaded poly(latic-co-glycolic acid) MSs to enhance islet survival and function as exenatide locally released in the intracapsular environment. The MCs with exenatide-loaded MSs showed improved glucose-stimulated response. The results indicate that the co-encapsulation concept of exenatide-loaded MSs with porcine islets is a promising strategy for achieving long-term survivability and function of islets, while overcoming donor shortage by reducing the required transplanted islet mass. Microencapsulation and controlled release of Pantoea agglomerans strain E325 (E325), an antagonist to the bacterial plant pathogen Erwinia amylovora that causes fire blight, a devastating disease of apple and pear, have been investigated. To preserve viability and promote proliferation, E325 was encapsulated with nutrients in core/shell MCs. Controlled release of E325 was achieved by separately adjusting alginate concentrations in the shell and core solutions, and by controlling the MC size. Proliferation of E325 within MCs, followed by their subsequent release, and colonization activities on apple flowers were investigated. This study could serve as a model for further studies on development of effective plant disease management strategies. Next, we focused on the feasibility of the MC-mediated treatment for field applications exposed to rapid and wide fluctuations in moisture and nutrient levels and storability of the inoculum. This study demonstrated the following advantages: (1) maintenance of E325 viability in moisture-poor environments including hypanthium, the most common site of infection, (2) improved suppressive activity against the pathogen of fire blight (strain Ea153) at various relative humidity, and (3) long-term survivability through lyoprotection and osmoadaptation

Periodic solutions for a generalized p-Laplacian equation

AbstractThe existence and uniqueness of T-periodic solutions for the following boundary value problems with p-Laplacian: (ϕp(x′))′+f(t,x′)+g(t,x)=e(t),x(0)=x(T),x′(0)=x′(T) are investigated, where ϕp(u)=∣u∣p−2u with p>1 and f,g,e are continuous and are T-periodic in t with f(t,0)=0. Using coincidence degree theory, some existence and uniqueness results are presented

Tgif1 Counterbalances The Activity Of Core Pluripotency Factors In Mouse Embryonic Stem Cells

Core pluripotency factors, such as Oct4, Sox2, and Nanog, play important roles in maintaining embryonic stem cell (ESC) identity by autoregulatory feedforward loops. Nevertheless, the mechanism that provides precise control of the levels of the ESC core factors without indefinite amplification has remained elusive. Here, we report the direct repression of core pluripotency factors by Tgif1, a previously known terminal repressor of TGF beta/activin/nodal signaling. Overexpression of Tgif1 reduces the levels of ESC core factors, whereas its depletion leads to the induction of the pluripotency factors. We confirm the existence of physical associations between Tgif1 and Oct4, Nanog, and HDAC1/2 and further show the level of Tgif1 is not significantly altered by treatment with an activator/inhibitor of the TGF beta/activin/nodal signaling. Collectively, our findings establish Tgif1 as an integral member of the core regulatory circuitry of mouse ESCs that counterbalances the levels of the core pluripotency factors in a TGF beta/activin/nodal-independent manner.Cancer Prevention Research Institute of Texas (CPRIT) R1106Molecular Bioscience

Optimization of coupling between photonic crystal resonator and curved microfiber

The evanescent coupling from a photonic crystal resonator to a micron-thick optical fiber is investigated in detail by using a 3D-FDTD method. Properly designed photonic crystal cavity and taper structures are proposed, and optimal operating conditions are found to enhance the coupling strength while suppressing other cavity losses including the coupling to the slab propagating mode and to the higher-order fiber mode. In simulation, the coupling into the fundamental fiber mode is discriminated from other cavity losses by spatial and parity filtering of the FDTD results. The coupling efficiency of more than 80% into the fundamental fiber mode together with a total Q factor of 5,200 is achieved for the fiber diameter of 1.0 um and the air gap of 200 nm between the fiber and the cavity.Comment: 6 pages, 6 figure

Measuring IS Service Quality in the Context of the Service Quality-User Satisfaction Relationship

There is little research regarding the relationship between IS service quality and user satisfaction, the most frequently used surrogate for information systems success. The current study is designed to investigate three ways of measuring service quality (i.e., confirmation/disconfirmation, perception-only, and overall assessment) and shed light on the relationship between service quality and user satisfaction. The results imply that when managers try to measure service quality to improve their service, they have to be cautious in ruling out or selecting one way or another of measuring service quality. The current research also clearly shows that mangers have to take care of the service quality to enhance user satisfaction. The models and results are discussed