315 research outputs found
The Economic and Fiscal Impacts of Hawaii's Solar Tax Credit
This research paper assesses the economic and fiscal impacts of Hawaii's solar tax credit-stimulated solar installations. The method entails estimating the economic effects created by i) the purchase of a solar system as well as ii) of the alternatives foregone. Our study shows that the State receives full repayment of its solar credit investment in 9 to 15 years. For each solar credit dollar spent, the State receives 2.67 dollars in additional tax revenues. The fiscal results of the tax credit reported by this research have been replicated in a federal solar tax credit study published by the US Partnership for Renewable Finance USPRF (2012) that estimates an IRR of 10% for the government's tax credit âinvestmentâ in residential solar systems. The findings of the federal study comports closely with our Hawaii's estimate of an IRR of 9.5% for residential and 11.1% for commercial solar systems.Â
Keywords: Solar Energy, Solar Tax Credit, Internal Rate of Return
JEL Classification: O
Conservation of oxidative protein stabilization in an insect homologue of the parkinsonism-associated protein DJ-1
DJ-1 is a conserved, disease-associated protein that protects against oxidative stress and mitochondrial damage in multiple organisms. Human DJ-1 contains a functionally essential cysteine residue (Cys106) whose oxidation is important for regulating protein function by an unknown mechanism. This residue is well conserved in other DJ-1 homologues, including two (DJ-1Îą and DJ-1β) in Drosophila melanogaster. Because D. melanogaster is a powerful model system for studying DJ-1 function, we have determined the crystal structure and impact of cysteine oxidation on Drosophila DJ-1β. The structure of D. melanogaster DJ-1β is similar to that of human DJ-1, although two important residues in the human protein, Met26 and His126, are not conserved in DJ-1β. His126 in human DJ-1 is substituted with a tyrosine in DJ-1β, and this residue is not able to compose a putative catalytic dyad with Cys106 that was proposed to be important in the human protein. The reactive cysteine in DJ-1 is oxidized readily to the cysteinesulfinic acid in both flies and humans and this may regulate the cytoprotective function of the protein. We show that the oxidation of this conserved cysteine residue to its sulfinate form (Cys- SO2 â) results in considerable thermal stabilization of both Drosophila DJ-1β and human DJ-1. Therefore, protein stabilization is one potential mechanism by which cysteine oxidation may regulate DJ-1 function in vivo. More generally, most close DJ-1 homologues are likely stabilized by cysteine-sulfinic acid formation but destabilized by further oxidation, suggesting that they are biphasically regulated by oxidative modification
Design, Development and Temporal Evaluation of an MRI-Compatible In-Vitro Circulation Model Using a Compliant AAA Phantom
Biomechanical characterization of abdominal aortic aneurysms (AAA) has become commonplace in rupture risk assessment studies. However, its translation to the clinic has been greatly limited due to the complexity associated with its tools and their implementation. The unattainability of patient-specific tissue properties leads to the use of generalized population-averaged material models in finite element analyses, which adds a degree of uncertainty to the wall mechanics quantification. In addition, computational fluid dynamics modeling of AAA typically lacks the patient-specific inflow and outflow boundary conditions that should be obtained by non-standard of care clinical imaging. An alternative approach for analyzing AAA flow and sac volume changes is to conduct in vitro experiments in a controlled laboratory environment. We designed, built, and characterized quantitatively a benchtop flow-loop using a deformable AAA silicone phantom representative of a patient-specific geometry. The impedance modules, which are essential components of the flow-loop, were fine-tuned to ensure typical intra-sac pressure conditions. The phantom was imaged with a magnetic resonance imaging (MRI) scanner to acquire time-resolved images of the moving wall and the velocity field inside the sac. Temporal AAA sac volume changes lead to a corresponding variation in compliance throughout the cardiac cycle. The primary outcome of this work was the design optimization of the impedance elements, the quantitative characterization of the resistive and capacitive attributes of a compliant AAA phantom, and the exemplary use of MRI for flow visualization and quantification of the deformed AAA geometry
Distinct exosomal mirna profiles from balf and lung tissue of copd and ipf patients
Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are chronic, progressive lung ailments that are characterized by distinct pathologies. Early detection biomarkers and disease mechanisms for these debilitating diseases are lacking. Extracellular vesicles (EVs), including exosomes, are small, lipid-bound vesicles attributed to carry proteins, lipids, and RNA molecules to facilitate cell-to-cell communication under normal and diseased conditions. Exosomal miRNAs have been studied in relation to many diseases. However, there is little to no knowledge regarding the miRNA population of bronchoalveolar lavage fluid (BALF) or the lung-tissue-derived exosomes in COPD and IPF. Here, we determined and compared the miRNA profiles of BALF-and lung-tissue-derived exosomes of healthy non-smokers, smokers, and patients with COPD or IPF in independent cohorts. Results: Exosome characterization using NanoSight particle tracking and TEM demonstrated that the BALF-derived exosomes were ~89.85 nm in size with a yield of ~2.95 Ă 1010 particles/mL in concentration. Lung-derived exosomes were larger in size (~146.04 nm) with a higher yield of ~2.38 Ă 1011 particles/mL. NGS results identified three differentially expressed miRNAs in the BALF, while there was one in the lung-derived exosomes from COPD patients as compared to healthy non-smokers. Of these, miR-122-5p was three-or five-fold downregulated among the lung-tissue-derived exosomes of COPD patients as compared to healthy non-smokers and smokers, respectively. Interestingly, there were a large number (55) of differentially expressed miRNAs in the lung-tissue-derived exosomes of IPF patients compared to non-smoking controls. Conclusions: Overall, we identified lung-specific miRNAs associated with chronic lung diseases that can serve as potential biomarkers or therapeutic targets
Distinct Exosomal miRNA Profiles from BALF and Lung Tissue of COPD and IPF Patients
Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are chronic, progressive lung ailments that are characterized by distinct pathologies. Early detection biomarkers and disease mechanisms for these debilitating diseases are lacking. Extracellular vesicles (EVs), including exosomes, are small, lipid-bound vesicles attributed to carry proteins, lipids, and RNA molecules to facilitate cell-to-cell communication under normal and diseased conditions. Exosomal miRNAs have been studied in relation to many diseases. However, there is little to no knowledge regarding the miRNA population of bronchoalveolar lavage fluid (BALF) or the lung-tissue-derived exosomes in COPD and IPF. Here, we determined and compared the miRNA profiles of BALF- and lung-tissue-derived exosomes of healthy non-smokers, smokers, and patients with COPD or IPF in independent cohorts. Results: Exosome characterization using NanoSight particle tracking and TEM demonstrated that the BALF-derived exosomes were ~89.85 nm in size with a yield of ~2.95 Ă 10(10) particles/mL in concentration. Lung-derived exosomes were larger in size (~146.04 nm) with a higher yield of ~2.38 Ă 10(11) particles/mL. NGS results identified three differentially expressed miRNAs in the BALF, while there was one in the lung-derived exosomes from COPD patients as compared to healthy non-smokers. Of these, miR-122-5p was three- or five-fold downregulated among the lung-tissue-derived exosomes of COPD patients as compared to healthy non-smokers and smokers, respectively. Interestingly, there were a large number (55) of differentially expressed miRNAs in the lung-tissue-derived exosomes of IPF patients compared to non-smoking controls. Conclusions: Overall, we identified lung-specific miRNAs associated with chronic lung diseases that can serve as potential biomarkers or therapeutic targets
The Staphylococcus aureus CidA and LrgA Proteins Are Functional Holins Involved in the Transport of By-Products of Carbohydrate Metabolism
The Staphylococcus aureus cidABC and lrgAB operons encode members of a well-conserved family of proteins thought to be involved in programmed cell death (PCD). Based on the structural similarities that CidA and LrgA share with bacteriophage holins, we have hypothesized that these proteins function by forming pores within the cytoplasmic membrane. To test this, we utilized a lysis cassette system that demonstrated the abilities of the cidA and lrgA genes to support bacteriophage endolysin-induced cell lysis. Typical of holins, CidA- and LrgA-induced lysis was dependent on the coexpression of endolysin, consistent with the proposed holin-like functions of these proteins. In addition, the CidA and LrgA proteins were shown to localize to the surface of membrane vesicles and cause leakage of small molecules, providing direct evidence of their hole-forming potential. Consistent with recent reports demonstrating a role for the lrgAB homologues in other bacterial and plant species in the transport of by-products of carbohydrate metabolism, we also show that lrgAB is important for S. aureus to utilize pyruvate during microaerobic and anaerobic growth, by promoting the uptake of pyruvate under these conditions. Combined, these data reveal that the CidA and LrgA membrane proteins possess holin-like properties that play an important role in the transport of small by-products of carbohydrate metabolism. IMPORTANCE The Staphylococcus aureus cidABC and lrgAB operons represent the founding members of a large, highly conserved family of genes that span multiple kingdoms of life. Despite the fact that they have been shown to be involved in bacterial PCD, very little is known about the molecular/biochemical functions of the proteins they encode. The results presented in this study reveal that the cidA and lrgA genes encode proteins with bacteriophage holin-like functions, consistent with their roles in cell death. However, these studies also demonstrate that these operons are involved in the transport of small metabolic by-products of carbohydrate metabolism, suggesting an intriguing link between these two seemingly disparate processes
Compartmentalisation and localisation of the translation initiation factor (eIF) 4F complex in normally growing fibroblasts
Previous observations of association of mRNAs and ribosomes with subcellular structures highlight the importance of localised translation. However, little is known regarding associations between eukaryotic translation initiation factors and cellular structures within the cytoplasm of normally growing cells. We have used detergent-based cellular fractionation coupled with immunofluorescence microscopy to investigate the subcellular localisation in NIH3T3 fibroblasts of the initiation factors involved in recruitment of mRNA for translation, focussing on eIF4E, the mRNA cap-binding protein, the scaffold protein eIF4GI and poly(A) binding protein (PABP). We find that these proteins exist mainly in a soluble cytosolic pool, with only a subfraction tightly associated with cellular structures. However, this "associated" fraction was enriched in active "eIF4F" complexes (eIF4E.eIF4G.eIF4A.PABP). Immunofluorescence analysis reveals both a diffuse and a perinuclear distribution of eIF4G, with the perinuclear staining pattern similar to that of the endoplasmic reticulum. eIF4E also shows both a diffuse staining pattern and a tighter perinuclear stain, partly coincident with vimentin intermediate filaments. All three proteins localise to the lamellipodia of migrating cells in close proximity to ribosomes, microtubules, microfilaments and focal adhesions, with eIF4G and eIF4E at the periphery showing a similar staining pattern to the focal adhesion protein vinculin
ParticleStats: open source software for the analysis of particle motility and cytoskeletal polarity
The study of dynamic cellular processes in living cells is central to biology and is particularly powerful when the motility characteristics of individual objects within cells can be determined and analysed statistically. However, commercial programs only offer a limited range of inflexible analysis modules and there are currently no open source programs for extensive analysis of particle motility. Here, we describe ParticleStats (http://www.ParticleStats.com), a web server and open source programs, which input the X,Y coordinate positions of objects in time, and output novel analyses, graphical plots and statistics for motile objects. ParticleStats comprises three separate analysis programs. First, ParticleStats:Directionality for the global analysis of polarity, for example microtubule plus end growth in Drosophila oocytes. Second, ParticleStats:Compare for the analysis of saltatory movement in terms of runs and pauses. This can be applied to chromosome segregation and molecular motor-based movements. Thirdly ParticleStats:Kymographs for the analysis of kymograph images, for example as applied to separation of chromosomes in mitosis. These analyses have provided key insights into molecular mechanisms that are not possible from qualitative analysis alone and are widely applicable to many other cell biology problems
Rapidly exploring structural and dynamic properties of signaling networks using PathwayOracle
<p>Abstract</p> <p>Background</p> <p>In systems biology the experimentalist is presented with a selection of software for analyzing dynamic properties of signaling networks. These tools either assume that the network is in steady-state or require highly parameterized models of the network of interest. For biologists interested in assessing how signal propagates through a network under specific conditions, the first class of methods does not provide sufficiently detailed results and the second class requires models which may not be easily and accurately constructed. A tool that is able to characterize the dynamics of a signaling network using an unparameterized model of the network would allow biologists to quickly obtain insights into a signaling network's behavior.</p> <p>Results</p> <p>We introduce <it>PathwayOracle</it>, an integrated suite of software tools for computationally inferring and analyzing structural and dynamic properties of a signaling network. The feature which differentiates <it>PathwayOracle </it>from other tools is a method that can predict the response of a signaling network to various experimental conditions and stimuli using only the connectivity of the signaling network. Thus signaling models are relatively easy to build. The method allows for tracking signal flow in a network and comparison of signal flows under different experimental conditions. In addition, <it>PathwayOracle </it>includes tools for the enumeration and visualization of coherent and incoherent signaling paths between proteins, and for experimental analysis â loading and superimposing experimental data, such as microarray intensities, on the network model.</p> <p>Conclusion</p> <p><it>PathwayOracle </it>provides an integrated environment in which both structural and dynamic analysis of a signaling network can be quickly conducted and visualized along side experimental results. By using the signaling network connectivity, analyses and predictions can be performed quickly using relatively easily constructed signaling network models. The application has been developed in Python and is designed to be easily extensible by groups interested in adding new or extending existing features. <it>PathwayOracle </it>is freely available for download and use.</p
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