Structural variants of biodegradable polyesterurethane in vivo evoke a cellular and angiogenic response that is dictated by architecture

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2008 Acta Materialia Inc.The aim of this study was to investigate an in vivo tissue response to a biodegradable polyesterurethane, specifically the cellular and angiogenic response evoked by varying implant architectures in a subcutaneous rabbit implant model. A synthetic biodegradable polyesterurethane was synthesized and processed into three different configurations: a non-porous film, a porous mesh and a porous membrane. Glutaraldehyde cross-linked bovine pericardium was used as a control. Sterile polyesterurethane and control samples were implanted subcutaneously in six rabbits (n = 12). The rabbits were killed at 21 and 63 days and the implant sites were sectioned and histologically stained using haemotoxylin and eosin (H&E), Masson’s trichrome, picosirius red and immunostain CD31. The tissue–implant interface thickness was measured from the H&E slides. Stereological techniques were used to quantify the tissue reaction at each time point that included volume fraction of inflammatory cells, fibroblasts, fibrocytes, collagen and the degree of vascularization. Stereological analysis inferred that porous scaffolds with regular topography are better tolerated in vivo compared to non-porous scaffolds, while increasing scaffold porosity promotes angiogenesis and cellular infiltration. The results suggest that this biodegradable polyesterurethane is better tolerated in vivo than the control and that structural variants of biodegradable polyesterurethane in vivo evoke a cellular and angiogenic response that is dictated by architecture.Irish Research Council for Science, Engineering and Technology: funded by the National Development Plan. Enterprise Ireland: Research Innovation Partnership

Phase diagram of the excitonic insulator

Motivated by recent experiments, which give strong evidence for an excitonic insulating phase in $\rm TmSe_{0.45}Te_{0.55}$, we developed a scheme to quantitatively construct, for generic two-band models, the phase diagram of an excitonic insulator. As a first application of our approach, we calculated the phase diagram for an effective mass two-band model with long-range Coulomb interaction. The shielded potential approximation is used to derive a generalized gap equation controlling for positive (negative) energy gaps the transition from a semi-conducting (semi-metallic) phase to an insulating phase. Numerical results,obtained within the quasi-static approximation, show a steeple-like phase diagram in contrast to long-standing expectations.Comment: 2 pages, 1 figure, SCES'05, accepted for publication in Physica

Role of the Predator Hemerobius pacificus in a Non-Insecticide Treated Artichoke Field

Hemerobius pacificus oviposition closely followed the population densities of Myzus persicae which peaked in late fall and declined to zero in spring in an untreated artichoke field. A second peak of oviposition by the predator followed the increasing populations of the artichoke plume moth (=APM), Platyptilia carduidactyla in spring. Where Hemerobius eggs were released, the aphid populations were reduced consistently, while the APM damage was reduced only at larval infestation levels of APM above 10%. Oviposition by wild Hemerobius was lower in plots where aphids had been reduced by released predators. APM infestations were estimated to be lowered by 30% by wild Hemerobius populations, while hymenopterous parasites accounted for 14% of the larval mortality of APM. Protein + sugar food sprays applied 5 times during the year slightly increased Hemerobius oviposition which in turn led to lower aphid populations and slightly reduced APM infestations. Hemerobius, the only common active predator in artichokes during winter, is considered an important control agent of aphids under cool conditions, and is a mortality factor of APM larvae. Hemerobius should be preserved in integrated control program

High-throughput and high-precision laser micromachining with ps-pulses in synchronized mode with a fast polygon line scanner

To be competitive in laser micro machining, high throughput is an important aspect. One possibility to increase productivity is scaling up the ablation process i.e. linearly increasing the laser repetition rate together with the average power and the scan speed. In the MHz-regime high scan speeds are required which cannot be provided by commercially available galvo scanners. In this work we will report on the results by using a polygon line scanner having a maximum scan speed of 100 m/s and a 50 W ps-laser system, synchronized via the SuperSync™ technology. We will show the results concerning the removal rate and the surface quality for working at the optimum point i.e. most efficient point at repetition rates up to 8.2 MHz

A Note on Classical Solution of Chaplygin-gas as D-brane

The classical solution of bosonic d-brane in (d+1,1) space-time is studied. We work with light-cone gauge and reduce the problem into Chaplygin gas problem. The static equation is equivalent to vanishing of extrinsic mean curvature, which is similar to Einstein equation in vacuum. We show that the d-brane problem in this gauge is closely related to Plateau problem, and we give some non-trivial solutions from minimal surfaces. The solutions of d-1,d,d+1 spatial dimensions are obtained from d-dimensional minimal surfaces as solutions of Plateau problem. In addition we discuss on the relation to Hamiltonian-BRST formalism for d-branes.Comment: 20 pages,No figures, Latex, Address change

Detecting Small-Scale Topographic Changes and Relict Geomorphic Features on Barrier Islands Using SAR

The shapes and elevations of barrier islands may change dramatically over a short period of time during a storm. Coastal scientists and engineers, however, are currently unable to measure these changes occurring over an entire barrier island at once. This three-year project, which is funded by NASA and jointly conducted by the Bureau of Economic Geology and the Center for Space Research at The University of Texas at Austin, is designed to overcome this problem by developing the use of interferometry from airborne synthetic aperture radar (AIRSAR) to measure coastal topography and to detect storm-induced changes in topography. Surrogate measures of topography observed in multiband, fully polarimetric AIRSAR (This type of data are now referred to as POLSAR data.) are also being investigated. Digital elevation models (DEM) of Galveston Island and Bolivar Peninsula, Texas obtained with Topographic SAR (TOPSAR) are compared with measurements by Global Positioning System (GPS) ground surveys and electronic total station surveys. In addition to topographic mapping, this project is evaluating the use of POLSAR to detect old features such as storm scarps, storm channels, former tidal inlets, and beach ridges that have been obscured by vegetation, erosion, deposition, and artificial filling. We have also expanded the work from the original proposal to include the mapping of coastal wetland vegetation and depositional environments. Methods developed during this project will provide coastal geologists with an unprecedented tool for monitoring and understanding barrier island systems. This understanding will improve overall coastal management policies and will help reduce the effects of natural and man-induced coastal hazards. This report summarizes our accomplishments during the second year of the study. Also included is a discussion of our planned activities for year 3 and a revised budget

MAR-Mediated transgene integration into permissive chromatin and increased expression by recombination pathway engineering.

Untargeted plasmid integration into mammalian cell genomes remains a poorly understood and inefficient process. The formation of plasmid concatemers and their genomic integration has been ascribed either to non-homologous end-joining (NHEJ) or homologous recombination (HR) DNA repair pathways. However, a direct involvement of these pathways has remained unclear. Here, we show that the silencing of many HR factors enhanced plasmid concatemer formation and stable expression of the gene of interest in Chinese hamster ovary (CHO) cells, while the inhibition of NHEJ had no effect. However, genomic integration was decreased by the silencing of specific HR components, such as Rad51, and DNA synthesis-dependent microhomology-mediated end-joining (SD-MMEJ) activities. Genome-wide analysis of the integration loci and junction sequences validated the prevalent use of the SD-MMEJ pathway for transgene integration close to cellular genes, an effect shared with matrix attachment region (MAR) DNA elements that stimulate plasmid integration and expression. Overall, we conclude that SD-MMEJ is the main mechanism driving the illegitimate genomic integration of foreign DNA in CHO cells, and we provide a recombination engineering approach that increases transgene integration and recombinant protein expression in these cells. Biotechnol. Bioeng. 2017;114: 384-396. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc

An overview of a systems model of cassava and cassava pests in Africa

A systems model is described for cassava, Manihot esculenta Crantz, two of its introduced herbivores, the cassava green mite (CGM), Mononychellus tanajoa (Bondar), sensu lato, and the cassava mealybug (CM), Phenacoccus manihoti Mat.-Ferr., the introduced CM parasitoid, Epidinocarsis lopezi (DeSantis) and coccinellid predator of the genus Hyperaspis. The systems model includes the effects of weather, soil nitrogen and water levels on the interactions of the system's components. The model simulates the distribution of developmental times of cohorts initated at the same time, as well as the number and biomass (energy) dynamics of all populations over time. Biomass acquisition and allocation at the population and organism subunit levels (e.g. leaves, fruit, ova) were also simulated. A common acquisition (i.e. functional response) submodel was used to estimate daily photosynthetic as well as nitrogen and water uptake rates in cassava, in addition to herbivory, parasitism and predation rates for the arthropod species. This paper presents an overview of the systems model. Simulation results for the plant under pest free conditions were compared to field data. In addition, the model was used to estimate tuber yield losses due to CM and CGM feeding, and to examine the beneficial effects of introduced CM natural enemies as measured by reductions in tuber yield losse

Cyclin-dependent kinase 18 controls trafficking of aquaporin-2 and its abundance through ubiquitin ligase STUB1, which functions as an AKAP

Arginine-vasopressin (AVP) facilitates water reabsorption in renal collecting duct principal cells through regulation of the water channel aquaporin-2 (AQP2). The hormone binds to vasopressin V2 receptors (V2R) on the surface of the cells and stimulates cAMP synthesis. The cAMP activates protein kinase A (PKA), which initiates signaling that causes an accumulation of AQP2 in the plasma membrane of the cells facilitating water reabsorption from primary urine and fine-tuning of body water homeostasis. AVP-mediated PKA activation also causes an increase in the AQP2 protein abundance through a mechanism that involves dephosphorylation of AQP2 at serine 261 and a decrease in its poly-ubiquitination. However, the signaling downstream of PKA that controls the localization and abundance of AQP2 is incompletely understood. We carried out an siRNA screen targeting 719 kinase-related genes, representing the majority of the kinases of the human genome and analyzed the effect of the knockdown on AQP2 by high-content imaging and biochemical approaches. The screening identified 13 hits whose knockdown inhibited the AQP2 accumulation in the plasma membrane. Amongst the candidates was the so far hardly characterized cyclin-dependent kinase 18 (CDK18). Our further analysis revealed a hitherto unrecognized signalosome comprising CDK18, an E3 ubiquitin ligase, STUB1 (CHIP), PKA and AQP2 that controls the localization and abundance of AQP2. CDK18 controls AQP2 through phosphorylation at serine 261 and STUB1-mediated ubiquitination. STUB1 functions as an A-kinase anchoring protein (AKAP) tethering PKA to the protein complex and bridging AQP2 and CDK18. The modulation of the protein complex may lead to novel concepts for the treatment of disorders which are caused or are associated with dysregulated AQP2 and for which a satisfactory treatment is not available, e.g., hyponatremia, liver cirrhosis, diabetes insipidus, ADPKD or heart failure