Cyclic Stretch Induces Inducible Nitric Oxide Synthase and Soluble Guanylate Cyclase in Pulmonary Artery Smooth Muscle Cells

In the pulmonary vasculature, mechanical forces such as cyclic stretch induce changes in vascular signaling, tone and remodeling. Nitric oxide is a potent regulator of soluble guanylate cyclase (sGC), which drives cGMP production, causing vasorelaxation. Pulmonary artery smooth muscle cells (PASMCs) express inducible nitric oxide synthase (iNOS), and while iNOS expression increases during late gestation, little is known about how cyclic stretch impacts this pathway. In this study, PASMC were subjected to cyclic stretch of 20% amplitude and frequency of 1 Hz for 24 h and compared to control cells maintained under static conditions. Cyclic stretch significantly increased cytosolic oxidative stress as compared to static cells (62.9 ± 5.9% vs. 33.3 ± 5.7% maximal oxidation), as measured by the intracellular redox sensor roGFP. Cyclic stretch also increased sGCβ protein expression (2.5 ± 0.9-fold), sGC activity (1.5 ± 0.2-fold) and cGMP levels (1.8 ± 0.2-fold), as well as iNOS mRNA and protein expression (3.0 ± 0.9 and 2.6 ± 0.7-fold, respectively) relative to control cells. An antioxidant, recombinant human superoxide dismutase (rhSOD), significantly decreased stretch-induced cytosolic oxidative stress, but did not block stretch-induced sGC activity. Inhibition of iNOS with 1400 W or an iNOS-specific siRNA inhibited stretch-induced sGC activity by 30% and 68% respectively vs. static controls. In conclusion, cyclic stretch increases sGC expression and activity in an iNOS-dependent manner in PASMC from fetal lambs. The mechanism that produces iNOS and sGC upregulation is not yet known, but we speculate these effects represent an early compensatory mechanism to counteract the effects of stretch-induced oxidative stress. A better understanding of the interplay between these two distinct pathways could provide key insights into future avenues to treat infants with pulmonary hypertension.     

The role of nuclear data for fusion technology studies

Nuclear data are of fundamental importance in studies of nuclear technology. In these studies, experiments to measure cross sections and decay properties and simulations of the design of fission power plants, fusion devices and accelerators are included. The large amount of data required is stored in computer readable formats in data libraries and the most common of these are the general purpose files used for neutronics or transport calculations. These files also contain the standards against which most measurements are made. The other class of libraries are the special purpose ones containing decay data, fission yields and cross section data for dosimetry and activation.This paper gives examples of what data are available and describes their use for various fusion applications. The focus will be on neutron-induced activation data with examples of how the reactions of particular importance can be identified. All data should be accompanied by estimates of the uncertainty. This is best achieved by including covariance data; however, this is extremely challenging and only a subset of the available data has such uncertainty data. The general principles of how covariance matrices are used are outlined.     

Abandoned Mine Drainage in the Swatara Creek Basin, Southern Anthracite Coalfield, Pennsylvania, USA: 1. Stream Water Quality Trends Coinciding with the Return of Fish

Acidic mine drainage (AMD) from legacy anthracite mines has contaminated Swatara Creek in eastern Pennsylvania. Intermittently collected base-flow data for 1959–1986 indicate that fish were absent immediately downstream from the mined area where pH ranged from 3.5 to 7.2 and concentrations of sulfate, dissolved iron, and dissolved aluminum were as high as 250, 2.0, and 4.7 mg/L, respectively. However, in the 1990s, fish returned to upper Swatara Creek, coinciding with the implementation of AMD treatment (limestone drains, limestone diversion wells, limestone sand, constructed wetlands) in the watershed. During 1996–2006, as many as 25 species of fish were identified in the reach downstream from the mined area, with base-flow pH from 5.8 to 7.6 and concentrations of sulfate, dissolved iron, and dissolved aluminum as high as 120, 1.2, and 0.43 mg/L, respectively. Several of the fish taxa are intolerant of pollution and low pH, such as river chub (Nocomis micropogon) and longnose dace (Rhinichthys cataractae). Cold-water species such as brook trout (Salvelinus fontinalis) and warm-water species such as rock bass (Ambloplites rupestris) varied in predominance depending on stream flow and stream temperature. Storm flow data for 1996–2007 indicated pH, alkalinity, and sulfate concentrations decreased as the stream flow and associated storm-runoff component increased, whereas iron and other metal concentrations were poorly correlated with stream flow because of hysteresis effects (greater metal concentrations during rising stage than falling stage). Prior to 1999, pH < 5.0 was recorded during several storm events; however, since the implementation of AMD treatments, pH has been maintained near neutral. Flow-adjusted trends for 1997–2006 indicated significant increases in calcium; decreases in hydrogen ion, dissolved aluminum, dissolved and total manganese, and total iron; and no change in sulfate or dissolved iron in Swatara Creek immediately downstream from the mined area. The increased pH and calcium from limestone in treatment systems can be important for mitigating toxic effects of dissolved metals. Thus, treatment of AMD during the 1990s improved pH buffering, reduced metals transport, and helped to decrease metals toxicity to fish.     

Levels of polybrominated diphenyl ether (PBDE) flame retardants in animals representing different trophic levels of the North Sea food Web

The levels of individual PBDE congeners were investigated in the invertebrate species whelk (Buccinum undatum), seastar (Asterias rubens), and hermit crab (Pagurus bernhardus), the gadoid fish species whiting (Merlangius merlangus) and cod (Gadus morhua), and the marine mammal species harbor seal (Phoca vitulina) and harbor porpoise (Phocoena phocoena). These species are all important representatives of different trophic levels of the North Sea food web. All six major PBDE congeners detected (BDEs 28, 47, 99, 100, 153, and 154) are most prevalent in the commercial Penta-BDE formulation. There is no evidence for the occurrence of the Octa-BDE formulation in the North Sea food web, since its dominant congener, BDE183, was never detected. BDE209, the main congener (> 97%) in the Deca-BDE formulation, was detected only in a minority of the samples and always in concentrations around the limit of detection. Since BDE209 is often the major BDE congener in sediments from the area, the main reason for its low concentrations in biota from the North Sea seems to be a relatively low bioaccumulation potential. This can either be due to a low uptake rate of the very large molecule or a relatively rapid excretion after biotransformation. Since all invertebrates investigated are sentinel species, they are highly representative for the area of capture. The highest lipid-normalized concentrations of PBDEs in the invertebrates occurred near the mouth of the river Tees at the East coast of the UK. The geographical distribution of the PBDEs can be explained by the residual currents in the area. The direction of these currents differs between the summer and the winter season as a result of the presence or absence of vertical summer stratification of the deeper waters north of the Dogger Bank. Summer stratification results in the development of a density-driven bottom water current formed after the onset of vertical stratification of the water column in May leaving the UK coast near Flamborough Head toward the Dogger Bank. In winter, the residual currents run in a more southerly direction and follow the UK coastline. The distribution pattern of the PCBs and p,p'-DDE in the invertebrates was entirely different from that of the PBDEs, which could be expected, since the use of these organochlorines in western Europe peaked in the 1960s and 1970s but has been forbidden more than two decades ago, whereas the production and use of the penta-BDE formulation is of a more recent origin. The higher trophic levels of the North Sea food web were represented by the predatory gadoid fish species whiting and cod and the marine mammal species harbor seal and harbor porpoise. The lipid-normalized levels of the six major PBDE congeners in fish were similar to the levels in the invertebrates, but a biomagnification step in concentrations of generally more than an order of magnitude occurred from gadoid fish to marine mammals. Based on the limited number of samples, no differences could be observed between harbor seal and harbor porpoise. In summary, the results in three species of sentinel invertebrates from a network of stations covering a major part of the North Sea basin showed that the estuary of the river Tees at the UK East coast is a major source for tri- to hexa-PBDEs. Throughout the food-chain, the most marked increase in (lipid-normalized) levels of all six PBDE congeners occurred from predatory (gadoid) fish to marine mammals, agreeing with the transition from gill-breathing to lung-breathing animals. This has serious consequences for the route of elimination of POPs, since their elimination from the blood into the ambient seawater via the gill-membrane is no longer possible.     

Social capital from carbon property: creating equity for indigenous people

New incentives for protection and in situ use of forests and the services they provide raise hopes for the reversal of tropical and temperate deforestation. Past management of forests appropriated the rights of forest communities, providing incentives to convert natural forest into financial capital through logging, while destroying the underlying physical property. Carbon trading aims to provide a means to convert the forest property into financial capital, while protecting the physical property of forests, thereby providing new incentives for in situ forest management. The potential for carbon-emission trading as a contributor to these new incentives is tempered by concerns that it is another tool for capitalists to exploit the indigenous communities of the developing world. Estimates of annual emission trading amounting to US $200 billion raise alarm bells about the effect of such trade in the developing world. People are right to be concerned, as the history of exploitation of indigenous people, the appropriation of their rights, the loss of forests and their benefits is well documented. This exploitation resulted in the exclusion of forest communities from the basic tenets for development created by the wealth generated by traded property. However, one virtue of trade is that it can be made subject to constraints. Through international treaties and agreements, trade can be constrained and national governments obliged to observe the rules of trade. The value of tradable carbon credits will be discounted or invalid if they do not meet these criteria, providing all parties with strong incentives to achieve the necessary performance standards relating to both processes and contracts. For carbon trading to develop social capital from natural capital requires the admission of forest communities into the polity and management of forest resources. In this paper we argue for responsible carbon-emission trading based on the clear and appropriate definition of carbon entitlements, with the proviso that trading respects the rights and needs of indigenous people. We adopt this position as emissions trading now seems inevitable and there should be proper rules to control this trade where it affects forests and their inhabitants. It is imperative that the poor and indigenous people are not excluded from these systems. Trading systems and the property systems they depend on need to be more accountable, transparent and inclusive of those features which we propose.     

Lumen pressure within obliquely insonated absorbent solid cylindrical shells with application to Doppler flow phantoms

Flow phantoms used in medical ultrasound usually employ a plastic tube as a blood vessel mimic. These tubes often have acoustic properties differing significantly from the tissue and blood-mimicking media, which results in distortion of the acoustic pressure field within the tubes and, hence, of the Doppler flow spectra. Previous analyses of this problem have used some form of the infinite plate transmission coefficient, although at least one ray-based analysis has considered a cylindrical interface but with zero wall thickness. In this paper, we compare these approximate pressure fields with the exact solution for oblique incidence on a viscoelastic cylindrical shell at 5 MHz to find for which materials the plate approximation is valid. The shell has water both inside and outside, but it can be modified to use a different fluid inside and also to include absorption in either fluid. We find the plate approximation is reasonable for soft tubes such as the copolymer Cflex (Cole-Palmer, Niles, IL) but much less so for hard tubes such as polymethylmethacrylate (PMMA)