1,453 research outputs found
Information Technology: Market Success To Succession
Since commercial computers were first introduced in the early 1950s, their role, power, and importance has so expanded that the current period is often called The Information Age. Over the past decade, policy makers and the public have become progressively more concerned as success in information markets has lead to a concentration of market power that allows a few firms to dominate what is increasingly seen as a commodity essential to modern life. This paper argues that, in modern information markets, success allows domination but also creates the conditions that lead to succession – the giants of one micro-age tend to become commodity suppliers to the movers and shakers of the next micro-age. This study separates the first 50 years of The Information Age into the Hardware and the Software Micro-ages. It is suggested that the user-training focus, of the now dawning Wetware Micro-age, will profoundly affect information markets and practises
An Extractive Sector Perspective of Risk Management and Its Influence on Corporate Sustainability: An Empirical Analysis
This study explores how risk management (RM), affects shareholder value (SV) and corporate sustainability (CS) in extractive-sector (ES) firms. Employees of Australia’s top 20 mining and oil-and-gas (O&G) firms were surveyed about their firm’s risk profile, risk attitudes, and RM practices. The survey drew 496 responses from 987 employees. The literature review raised several gaps: Does RM enhance SV and CS of ES firms; How similar is RM across ES firms; Are mining and O&G risks sufficiently different to warrant splitting them? The survey findings suggest that ES-firm risk profiles, risk attitudes, and RM practices are: Broader than in non-ES firms; Important to SV via CS; and Similar within and across mining and O&G. Survey responses suggest that ES employees recognize the nature of RM and of the importance of the ES sector via employment, investment, and raw-material flows. This study affirms that mining- and O&G-firmRM practices are converging and is a benchmark for future studies, as high-carbon energy (coal mining and O&G) is supplanted by nuclear and non-ES-renewable energy
CHO genome mining for synthetic promoter design
Synthetic promoters are an attractive alternative for use in mammalian hosts such as CHO cells as they can be designed de novo with user-defined functionalities. In this study, we describe and validate a method for bioprocess-directed design of synthetic promoters utilizing CHO genomic sequence information. We designed promoters with two objective features, (i) constitutive high-level recombinant gene transcription, and (ii) upregulated transcription under mild hypothermia or late-stage culture. CHO genes varying in transcriptional activity were selected based on a comparative analysis of RNA-Seq transcript levels in normal and biphasic cultures in combination with estimates of mRNA half-life from published genome scale datasets. Discrete transcription factor regulatory elements (TFREs) upstream of these genes were informatically identified and functionally screened in vitro to identify a subset of TFREs with the potential to support high activity recombinant gene transcription during biphasic cell culture processes. Two libraries of heterotypic synthetic promoters with varying TFRE combinations were then designed in silico that exhibited a maximal 2.5-fold increase in transcriptional strength over the CMV-IE promoter after transient transfection into host CHO-K1 cells. A subset of synthetic promoters was then used to create stable transfectant pools using CHO-K1 cells under glutamine synthetase selection. Whilst not achieving the maximal 2.5-fold increase in productivity over stable pools harboring the CMV promoter, all stably transfected cells utilizing synthetic promoters exhibited increased reporter production - up to 1.6-fold that of cells employing CMV, both in the presence or absence of intron A immediately downstream of the promoter. The increased productivity of stably transfected cells harboring synthetic promoters was maintained during fed-batch culture, with or without a transition to mild hypothermia at the onset of stationary phase. Our data exemplify that it is important to consider both host cell and intended bioprocess contexts as design criteria in the de novo construction of synthetic genetic parts for mammalian cell engineering
The quantitative proteomic response of Synechocystis sp. PCC6803 to phosphate acclimation.
BACKGROUND: Inorganic phosphate (Pi) is a critical nutrient for all life and is periodically limiting in marine and freshwater provinces, yet little is understood how organisms acclimate to fluctuations in Pi within their environment. To investigate whole cell adaptation, we grew Synechocystis sp. PCC6803, a model freshwater cyanobacterium, in 3%, and 0.3% inorganic phosphate (Pi) media. The cells were allowed to acclimate over 60 days, and cells were harvested for quantitative high throughput mass spectrometry-based proteomics using the iTRAQ™ labelling technology. RESULTS: In total, 120 proteins were identified, and 52 proteins were considered differentially abundant compared to the control. Alkaline phosphatase (APase) activities correlated significantly (p < 0.05) with observed relative PhoA abundances. PstS1 and PstS2 were both observed, yet PstS1 was not differentially more abundant than the control. Phycobilisome protein abundances appeared to be coordinated, and are significantly less abundant in 0.3% Pi than 3% Pi cultures. Also, the central metabolic cell function appears to have shifted towards the production of (NADPH) reducing energy and nucleotide sugars. CONCLUSIONS: This acclimation response bears strong similarity to the previously reported response to nitrogen deprivation within Synechocystis sp. PCC 6803. However, it also demonstrates some characteristics of desiccation stress, such as the regulation of fatty acids and increased abundance of rehydrin in the 3% Pi culture
Direct Selective Laser Sintering of Tool Steel Powders to High Density: Part B -The Effect on Microstructural Evolution
This paper describes recent progress on the Direct Selective Laser Sintering of M2 [Fe6W-5Mo-4Cr-2V-0.8C] high speed steel (HSS) and H13 [Fe-5Cr-1V-1Si-1.5Mo-0.4C] tool steel
powders. Part B will focus on the microstructural evolution of laser scanned powder beds. It has
been found that H13 powders are more amenable to Direct Selective Laser Sintering than M2
powders. Densities up to 90% are possible with H13 powder compared with 70% for M2. The
relationship between alloy composition, microstructure, post-scanned density and scan
conditions will be discussed for single track, single layer and multi-layer constructions.The research reported in this paper is a joint project between the Universities of Bradford, Leeds
and Liverpool, funded by the UK Engineering and Physical Sciences Research Council under
Grant Number GR/R32222.Mechanical Engineerin
Direct Selective Laser Sintering of Tool Steel Powders to High Density: Part A - Effects of Laser Beam Width and Scan Strategy
This paper describes progress on the Direct Selective Laser Sintering of M2 and H13 tool
steel powders, comparing this with previous and further observations on stainless steel powders.
The distinguishing feature is the melting of single tracks and layers in deep powder beds. The
paper focuses on changing characteristics of the melt pool (mass, volume, aspect ratio, stability)
and laser-powder interactivity as the laser beam width, power and scan speed change. It also
compares the melt pool of neighbouring tracks during single layer construction. Simulations
from a computer model to predict melt pool shape and dimension show reasonable agreement
with experimental results at low scan speeds (0.5mm/s). But unexpected increases in melt depth
above 1.0mm/s have been observed, suggesting higher values and more variability in laser
absorptivity than expected, even approaching 1.0 for the CO2 laser radiation used in this work.Mechanical Engineerin
Prioritization of HCV treatment in the direct-acting antiviral era: an economic evaluation
BACKGROUND & AIMS: We determined the optimal HCV treatment prioritization strategy for interferon-free (IFN-free) HCV direct-acting antivirals (DAAs) by disease stage and risk status incorporating treatment of people who inject drugs (PWID). METHODS: A dynamic HCV transmission and progression model compared the cost-effectiveness of treating patients early vs. delaying until cirrhosis for patients with mild or moderate fibrosis, where PWID chronic HCV prevalence was 20, 40 or 60%. Treatment duration was 12weeks at £3300/wk, to achieve a 95% sustained viral response and was varied by genotype/stage in alternative scenarios. We estimated long-term health costs (in £UK=€1.3=$1.5) and outcomes as quality adjusted life-years (QALYs) gained using a £20,000 willingness to pay per QALY threshold. We ranked strategies with net monetary benefit (NMB); negative NMB implies delay treatment. RESULTS: The most cost-effective group to treat were PWID with moderate fibrosis (mean NMB per early treatment £60,640/£23,968 at 20/40% chronic prevalence, respectively), followed by PWID with mild fibrosis (NMB £59,258 and £19,421, respectively) then ex-PWID/non-PWID with moderate fibrosis (NMB £9,404). Treatment of ex-PWID/non-PWID with mild fibrosis could be delayed (NMB -£3,650). In populations with 60% chronic HCV among PWID it was only cost-effective to prioritize DAAs to ex-PWID/non-PWID with moderate fibrosis. For every one PWID in the 20% chronic HCV setting, 2 new HCV infections were averted. One extra HCV-related death was averted per 13 people with moderate disease treated. Rankings were unchanged with reduced drug costs or varied sustained virological response/duration by genotype/fibrosis stage. CONCLUSIONS: Treating PWID with moderate or mild HCV with IFN-free DAAs is cost-effective compared to delay until cirrhosis, except when chronic HCV prevalence and reinfection risk is very high
Differential iron requirements for osteoblast and adipocyte differentiation
Bone marrow mesenchymal progenitor cells are precursors for various cell types including osteoblasts, adipocytes, and chondrocytes. The external environment and signals act to direct the pathway of differentiation. Importantly, situations such as aging and chronic kidney disease display alterations in the balance of osteoblast and adipocyte differentiation, adversely affecting bone integrity. Iron deficiency, which can often occur during aging and chronic kidney disease, is associated with reduced bone density. The purpose of this study was to assess the effects of iron deficiency on the capacity of progenitor cell differentiation pathways. Mouse and human progenitor cells, differentiated under standard osteoblast and adipocyte protocols in the presence of the iron chelator deferoxamine (DFO), were used. Under osteogenic conditions, 5μM DFO significantly impaired expression of critical osteoblast genes, including osteocalcin, type 1 collagen, and dentin matrix protein 1. This led to a reduction in alkaline phosphatase activity and impaired mineralization. Despite prolonged exposure to chronic iron deficiency, cells retained viability as well as normal hypoxic responses with significant increases in transferrin receptor and protein accumulation of hypoxia inducible factor 1α. Similar concentrations of DFO were used when cells were maintained in adipogenic conditions. In contrast to osteoblast differentiation, DFO modestly suppressed adipocyte gene expression of peroxisome-proliferating activated receptor gamma, lipoprotein lipase, and adiponectin at earlier time points with normalization at later stages. Lipid accumulation was also similar in all conditions. These data suggest the critical importance of iron in osteoblast differentiation, and as long as the external stimuli are present, iron deficiency does not impede adipogenesis. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.Daniel F. Edwards III, Christopher J. Miller, Arelis Quintana-Martinez, Christian S. Wright, Matthew Prideaux, Gerald J. Atkins, William R. Thompson, and Erica L. Clinkenbear
Mitochondrial haplotypes reveal low diversity and restricted connectivity of the critically endangered batoid population in a Marine Protected Area
Stability and long-term persistence of a species rely heavily on its genetic diversity, which is closely allied to its capacity for adaptation. In threatened species, population connectivity can play a major role in maintaining that diversity, and genetic assessments of their populations can be crucial for the design of effective spatial conservation management. Not only is it worth evaluating the amount of diversity in a candidate population for protection, but the magnitude of outgoing gene flow can provide insight into its potential to replenish others via emigrants. The critically endangered flapper skate Dipturus intermedius receives protection in the Loch Sunart to the Sound of Jura Marine Protected Area (MPA) in Scotland. However, there is insufficient knowledge of genetic diversity and connectivity across its range. Recent tagging studies in the MPA suggest the presence of animals with high levels of site fidelity and residency, as well as transient individuals, raising concerns of limited connectivity to populations beyond the MPA. In this study, a newly developed mitochondrial haplotype marker allowed use of DNA sourced from fin clips, mucus and egg cases to investigate population structure and mitochondrial variability across several sites around the British Isles, including the MPA. Unfortunately, results characterized the MPA as having particularly low haplotype diversity and significant population differentiation from other sample sites. More than a quarter of its individuals carry a haplotype rarely observed elsewhere, leaving outgoing gene flow questionable. The MPA appears unlikely to sustain the species{\textquoteright} existing mtDNA genetic diversity or act as an effective source population
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