Adapting Stand‐Alone Renewable Energy Technologies for the Circular Economy through Eco‐Design and Recycling

Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.     

Global patterns in fine root decomposition: climate,chemistry, mycorrhizal association and woodiness

Fine root decomposition constitutes a critical yet poorly understood flux of carbon and nutrients in terrestrial ecosystems. Here, we present the first large‐scale synthesis of species trait effects on the early stages of fine root decomposition at both global and local scales. Based on decomposition rates for 279 plant species across 105 studies and 176 sites, we found that mycorrhizal association and woodiness are the best categorical traits for predicting rates of fine root decomposition. Consistent positive effects of nitrogen and phosphorus concentrations and negative effects of lignin concentration emerged on decomposition rates within sites. Similar relationships were present across sites, along with positive effects of temperature and moisture. Calcium was not consistently related to decomposition rate at either scale. While the chemical drivers of fine root decomposition parallel those of leaf decomposition, our results indicate that the best plant functional groups for predicting fine root decomposition differ from those predicting leaf decomposition.     

Multi-patch deterministic and stochastic models for wildlife diseases

Spatial heterogeneity and host demography have a direct impact on the persistence or extinction of a disease. Natural or human-made landscape features such as forests, rivers, roads, and crops are important to the persistence of wildlife diseases. Rabies, hantaviruses, and plague are just a few examples of wildlife diseases where spatial patterns of infection have been observed. We formulate multi-patch deterministic and stochastic epidemic models and use these models to investigate problems related to disease persistence and extinction. We show in some special cases that a unique disease-free equilibrium exists. In these cases, a basic reproduction number ?(0) can be computed and shown to be bounded below and above by the minimum and maximum patch reproduction numbers ?(j), j=1, …, n. The basic reproduction number has a simple form when there is no movement or when all patches are identical or when the movement rate approaches infinity. Numerical examples of the deterministic and stochastic models illustrate the disease dynamics for different movement rates between three patches.     

Soil biota,carbon cycling and crop plant biomass responses to biochar in a temperate mesocosm experiment

Plant and Soil - Shifts of plant community composition with enhanced atmospheric nitrogen (N) deposition in grasslands have occurred globally. Despite extensive studies on the effects of enhanced N...     

Relative contribution of hemopoietic and pulmonary parenchymal cells to lung inducible nitric oxide synthase (inos) activity in murine endotoxemia

Acute lung injury is an important feature of sepsis and increased iNOS expression and NO production contribute to the pathogenesis of this syndrome. We generated bone marrow-transplanted chimeric mice with iNOS expression limited to either inflammatory or pulmonary parenchymal cells, and assessed pulmonary iNOS activity and systemic levels of NO metabolites in an endotoxemic model of sepsis. We found that while both pulmonary parenchymal cells and inflammatory cells contribute to the increased lung iNOS activity in endotoxemia, pulmonary parenchymal cells contribute to a significantly greater degree. Using measurement of plasma NO(-)(x), whole body NO production was assessed in this model. We found that the main source of NO(-)(x) was again, parenchymal cells and not inflammatory cells. This is the first study to demonstrate that most of the increased NO production in this model of endotoxemic sepsis derives from parenchymal cells rather than inflammatory cells.     

Synthesis and X-ray crystal structure of [Ag(phendio)<Subscript>2</Subscript>]ClO<Subscript>4</Subscript> (phendio = 1,10-phenanthroline-5,6-dione) and its effects on fungal and mammalian cells

The Cu(II) and Ag(I) complexes, [Cu(phendio)₃](ClO₄)₂4H₂O and [Ag(phendio)₂]ClO₄ (phendio = 1,10-phenanthroline-5,6-dione), are prepared in good yield by reacting phendio with the appropriate metal perchlorate salt. The X-ray crystal structure of the Ag(I) complex shows it to have a pseudo tetrahedral structure. `Metal-free' phendio and the Cu(II) and Ag(I) phendio complexes strongly inhibit the growth of the fungal pathogen Candida albicans, and are more active than their 1,10-phenanthroline analogues. The simple Ag(I) salts, AgCH<sub>3</sub>CO<sub>2</sub>, AgNO<sub>3</sub> and AgClO<sub>4</sub>.H<sub>2</sub>O display superior anti-fungal properties compared to analogous simple Cu(II) and Mn(II) salts, suggesting that the nature of the metal ion strongly influences activity. Exposing C. albicans to `metal-free' phendio, simple Ag(I) salts and [Ag(phendio)₂]ClO₄ causes extensive, non-specific DNA cleavage. `Metal-free' phendio and [Ag(phendio)₂]ClO₄ induce gross distortions in fungal cell morphology and there is evidence for disruption of cell division. Both drugs also exhibit high anti-cancer activity when tested against cultured mammalian cells.     

Proteome analysis reveals phosphorylation of ATP synthase beta -subunit in human skeletal muscle and proteins with potential roles in type 2 diabetes

Insulin resistance in skeletal muscle is a hallmark feature of type 2 diabetes. An increasing number of enzymes and metabolic pathways have been implicated in the development of insulin resistance. However, the primary cellular cause of insulin resistance remains uncertain. Proteome analysis can quantitate a large number of proteins and their post-translational modifications simultaneously and is a powerful tool to study polygenic diseases like type 2 diabetes. Using this approach on human skeletal muscle biopsies, we have identified eight potential protein markers for type 2 diabetes in the fasting state. The observed changes in protein expression indicate increased cellular stress, e.g. up-regulation of two heat shock proteins, and perturbations in ATP (re)synthesis and mitochondrial metabolism, e.g. down-regulation of ATP synthase beta-subunit and creatine kinase B, in skeletal muscle of patients with type 2 diabetes. Phosphorylation appears to play a key, potentially coordinating role for most of the proteins identified in this study. In particular, we demonstrated that the catalytic beta-subunit of ATP synthase is phosphorylated in vivo and that the levels of a down-regulated ATP synthase beta-subunit phosphoisoform in diabetic muscle correlated inversely with fasting plasma glucose levels. These data suggest a role for phosphorylation of ATP synthase beta-subunit in the regulation of ATP synthesis and that alterations in the regulation of ATP synthesis and cellular stress proteins may contribute to the pathogenesis of type 2 diabetes.     

Mutational screen identifies critical amino acid residues of beta-actin mediating interaction between its folding intermediates and eukaryotic cytosolic chaperonin CCT

The three-dimensional reconstruction of apo-CCT-alpha-actin by cryoelectron microscopy shows that actin binds either the CCTbeta-CCTdelta or the CCTepsilon-CCTdelta subunit pairs of the chaperonin in an open and apparently quasi-native conformation. The CCT-binding sites are seen located at the tips of the two arms of actin and these same regions of actin have been implicated in CCT binding through beta-actin peptide-array screening. Three main CCT binding regions exist: actin Sites I, II, and III, which are composed of loops that are surface-exposed in native actin. Sixty-eight amino acid residues on beta-actin have been screened by mutagenesis for effects on CCT interaction in quantitative in vitro translation assays in rabbit reticulocyte lysate. Actin seems to be folding cooperatively on chaperonin, since certain mutants discriminate CCT binding from processing. Actin Site II, located at the tip of actin subdomain 4, is the major determinant for CCT binding. Site II is composed of two anti-parallel extended beta-strands, with F200-T203 and D244 contributing substantially to the binding site. The substrate recognition chemistry of CCT thus seems different from that of Group I chaperonins and probably reflects the fact that it needs to be highly specific to enable capture and folding of the actins and tubulins.