278 research outputs found
A rusty record of weathering and groundwater movement in the hyperarid Central Andes
The Atacama Desert, on the western margin of the Central Andes, hosts some of the world's largest porphyry copper deposits (PCDs). Despite a hyperarid climate, many of these PCDs have undergone secondary āsupergeneā enrichment, whereby copper has been concentrated via groundwater-driven leaching and reprecipitation, yielding supergene profiles containing valuable records of weathering and landscape evolution. We combine hematite (U-Th-Sm)/He geochronology and oxygen isotope analysis to compare the weathering histories of two Andean PCDs and test the relative importance of climate and tectonics in controlling both enrichment and water table movement. At Cerro Colorado, in the Precordillera, hematite precipitation records prolonged weathering from ā¼31 to ā¼2 Ma, tracking water table descent following aridity-induced canyon incision from the late Miocene onward. By contrast, hematite at Spence, within the Central Depression, is mostly younger than ā¼10.5 Ma, suggesting exhumation ended much later. A heavy oxygen isotopic signature for Spence hematite suggests that upwelling formation water has been an important source of groundwater, accounting for a high modern water table despite persistent hyperaridity, whereas isotopically light hematite at Cerro Colorado formed in the presence of meteoric water. Compared with published paleo-environmental and sedimentological records, our data show that weathering can persist beneath appreciable post-exhumation cover, under hyperarid conditions unconducive to enrichment. The susceptibility of each deposit to aridity-induced water table descent, canyon incision and deep weathering has been controlled by recharge characteristics and morphotectonic setting. Erosional exhumation, rather than aridity-induced water table decay, appears to be more important for the development of supergene enrichment
An immortalised mesenchymal stem cell line maintains mechano-responsive behaviour and can be used as a reporter of substrate stiffness
The mechanical environment can influence cell behaviour, including changes to transcriptional and proteomic regulation, morphology and, in the case of stem cells, commitment to lineage. However, current tools for characterizing substratesā mechanical properties, such as atomic force microscopy (AFM), often do not fully recapitulate the length and time scales over which cells āfeelā substrates. Here, we show that an immortalised, clonal line of human mesenchymal stem cells (MSCs) maintains the responsiveness to substrate mechanics observed in primary cells, and can be used as a reporter of stiffness. MSCs were cultured on soft and stiff polyacrylamide hydrogels. In both primary and immortalised MSCs, stiffer substrates promoted increased cell spreading, expression of lamin-A/C and translocation of mechano-sensitive proteins YAP1 and MKL1 to the nucleus. Stiffness was also found to regulate transcriptional markers of lineage. A GFP-YAP/RFP-H2B reporter construct was designed and virally delivered to the immortalised MSCs for in situ detection of substrate stiffness. MSCs with stable expression of the reporter showed GFP-YAP to be colocalised with nuclear RFP-H2B on stiff substrates, enabling development of a cellular reporter of substrate stiffness. This will facilitate mechanical characterisation of new materials developed for applications in tissue engineering and regenerative medicine
Recommended from our members
Enabling precision medicine in neonatology, an integrated repository for preterm birth research.
Preterm birth, or the delivery of an infant prior to 37 weeks of gestation, is a significant cause of infant morbidity and mortality. In the last decade, the advent and continued development of molecular profiling technologies has enabled researchers to generate vast amount of 'omics' data, which together with integrative computational approaches, can help refine the current knowledge about disease mechanisms, diagnostics, and therapeutics. Here we describe the March of Dimes' Database for Preterm Birth Research (http://www.immport.org/resources/mod), a unique resource that contains a variety of 'omics' datasets related to preterm birth. The database is open publicly, and as of January 2018, links 13 molecular studies with data across tens of thousands of patients from 6 measurement modalities. The data in the repository are highly diverse and include genomic, transcriptomic, immunological, and microbiome data. Relevant datasets are augmented with additional molecular characterizations of almost 25,000 biological samples from public databases. We believe our data-sharing efforts will lead to enhanced research collaborations and coordination accelerating the overall pace of discovery in preterm birth research
Exploring the Use of Cost-Benefit Analysis to Compare Pharmaceutical Treatments for Menorrhagia
Background: The extra-welfarist theoretical framework tends to focus on health-related quality of life, whilst the welfarist framework captures a wider notion of well-being. EQ-5D and SF-6D are commonly used to value outcomes in chronic conditions with episodic symptoms, such as heavy menstrual bleeding (clinically termed menorrhagia). Because of their narrow-health focus and the conditionās periodic nature these measures may be unsuitable. A viable alternative measure is willingness to pay (WTP) from the welfarist framework. Objective: We explore the use of WTP in a preliminary cost-benefit analysis comparing pharmaceutical treatments for menorrhagia.
Methods: A cost-benefit analysis was carried out based on an outcome of WTP. The analysis is based in the UK primary care setting over a 24-month time period, with a partial societal perspective. Ninety-nine women completed a WTP exercise from the ex-ante (pre-treatment/condition) perspective. Maximum average WTP values were elicited for two pharmaceutical treatments, levonorgestrel-releasing intrauterine system (LNG-IUS) and oral treatment. Cost data were offset against WTP and the net present value derived for treatment. Qualitative information explaining the WTP values was also collected.
Results: Oral treatment was indicated to be the most cost-beneficial intervention costing Ā£107 less than LNG-IUS and generating Ā£7 more benefits. The mean incremental net present value for oral treatment compared with LNG-IUS was Ā£113. The use of the WTP approach was acceptable as very few protests and non-responses were observed. Conclusion: The preliminary cost-benefit analysis results recommend oral treatment as the first-line treatment for menorrhagia. The WTP approach is a feasible alternative to the conventional EQ-5D/SF-6D approaches and offers advantages by capturing benefits beyond health, which is particularly relevant in menorrhagia
Full Genome Characterization of the Culicoides-Borne Marsupial Orbiviruses: Wallal Virus, Mudjinbarry Virus and Warrego Viruses
Viruses belonging to the species Wallal virus and Warrego virus of the genus Orbivirus were identified as causative agents of blindness in marsupials in Australia during 1994/5. Recent comparisons of nucleotide (nt) and amino acid (aa) sequences have provided a basis for the grouping and classification of orbivirus isolates. However, full-genome sequence data are not available for representatives of all Orbivirus species. We report full-genome sequence data for three additional orbiviruses: Wallal virus (WALV); Mudjinabarry virus (MUDV) and Warrego virus (WARV). Comparisons of conserved polymerase (Pol), sub-core-shell 'T2' and core-surface 'T13' proteins show that these viruses group with other Culicoides borne orbiviruses, clustering with Eubenangee virus (EUBV), another orbivirus infecting marsupials. WARV shares <70% aa identity in all three conserved proteins (Pol, T2 and T13) with other orbiviruses, consistent with its classification within a distinct Orbivirus species. Although WALV and MUDV share <72.86%/67.93% aa/nt identity with other orbiviruses in Pol, T2 and T13, they share >99%/90% aa/nt identities with each other (consistent with membership of the same virus species - Wallal virus). However, WALV and MUDV share <68% aa identity in their larger outer capsid protein VP2(OC1), consistent with membership of different serotypes within the species - WALV-1 and WALV-2 respectively
Strain and bioprocess improvement of a thermophilic anaerobe for the production of ethanol from wood
Genome-scale resources for Thermoanaerobacterium saccharolyticum
Background Thermoanaerobacterium saccharolyticum is a hemicellulose-degrading thermophilic anaerobe that was previously engineered to produce ethanol at high yield. A major project was undertaken to develop this organism into an industrial biocatalyst, but the lack of genome information and resources were recognized early on as a key limitation. Results Here we present a set of genome-scale resources to enable the systems level investigation and development of this potentially important industrial organism. Resources include a complete genome sequence for strain JW/SL-YS485, a genome-scale reconstruction of metabolism, tiled microarray data showing transcription units, mRNA expression data from 71 different growth conditions or timepoints and GC/MS-based metabolite analysis data from 42 different conditions or timepoints. Growth conditions include hemicellulose hydrolysate, the inhibitors HMF, furfural, diamide, and ethanol, as well as high levels of cellulose, xylose, cellobiose or maltodextrin. The genome consists of a 2.7 Mbp chromosome and a 110 Kbp megaplasmid. An active prophage was also detected, and the expression levels of CRISPR genes were observed to increase in association with those of the phage. Hemicellulose hydrolysate elicited a response of carbohydrate transport and catabolism genes, as well as poorly characterized genes suggesting a redox challenge. In some conditions, a time series of combined transcription and metabolite measurements were made to allow careful study of microbial physiology under process conditions. As a demonstration of the potential utility of the metabolic reconstruction, the OptKnock algorithm was used to predict a set of gene knockouts that maximize growth-coupled ethanol production. The predictions validated intuitive strain designs and matched previous experimental results. Conclusion These data will be a useful asset for efforts to develop T. saccharolyticum for efficient industrial production of biofuels. The resources presented herein may also be useful on a comparative basis for development of other lignocellulose degrading microbes, such as Clostridium thermocellum. Electronic supplementary material The online version of this article (doi:10.1186/s12918-015-0159-x) contains supplementary material, which is available to authorized users
Recommended from our members
Cross-Country Individual Participant Analysis of 4.1 Million Singleton Births in 5 Countries with Very High Human Development Index...
Background:
Preterm birth is the most common single cause of perinatal and infant mortality, affecting 15 million infants worldwide each year with global rates increasing. Understanding of risk factors remains poor, and preventive interventions have only limited benefit. Large differences exist in preterm birth rates across high income countries. We hypothesized that understanding the basis for these wide variations could lead to interventions that reduce preterm birth incidence in countries with high rates. We thus sought to assess the contributions of known risk factors for both spontaneous and provider-initiated preterm birth in selected high income countries, estimating also the potential impact of successful interventions due to advances in research, policy and public health, or clinical practice.
Methods:
We analyzed individual patient-level data on 4.1 million singleton pregnancies from four countries with very high human development index (Czech Republic, New Zealand, Slovenia, Sweden) and one comparator U.S. state (California) to determine the specific contribution (adjusting for confounding effects) of 21 factors. Both individual and population-attributable preterm birth risks were determined, as were contributors to cross-country differences. We also assessed the ability to predict preterm birth given various sets of known risk factors.
Findings:
Previous preterm birth and preeclampsia were the strongest individual risk factors of preterm birth in all datasets, with odds ratios of 4.6ā6.0 and 2.8ā5.7, respectively, for individual women having those characteristics. In contrast, on a population basis, nulliparity and male sex were the two risk factors with the highest impact on preterm birth rates, accounting for 25ā50% and 11ā16% of excess population attributable risk, respectively (p < 0.001). The importance of nulliparity and male sex on population attributable risk was driven by high prevalence despite low odds ratios for individual women. More than 65% of the total aggregated risk of preterm birth within each country lacks a plausible biologic explanation, and 63% of difference between countries cannot be explained with known factors; thus, research is necessary to elucidate the underlying mechanisms of preterm birth and, hence, therapeutic intervention. Surprisingly, variation in prevalence of known risk factors accounted for less than 35% of the difference in preterm birth rates between countries. Known risk factors had an area under the curve of less than 0.7 in ROC analysis of preterm birth prediction within countries. These data suggest that other influences, as yet unidentified, are involved in preterm birth. Further research into biological mechanisms is warranted.
Conclusions:
We have quantified the causes of variation in preterm birth rates among countries with very high human development index. The paucity of explicit and currently identified factors amenable to intervention illustrates the limited impact of changes possible through current clinical practice and policy interventions. Our research highlights the urgent need for research into underlying biological causes of preterm birth, which alone are likely to lead to innovative and efficacious interventions
Recommended from our members
Farmer attitudes and livestock disease: exploring citizenship behaviour and peer monitoring across two BVD control schemes in the UK
The eradication of BVD in the UK is technically possible but appears to be socially untenable. The following study explored farmer attitudes to BVD control schemes in relation to advice networks and information sharing, shared aims and goals, motivation and benefits of membership, notions of BVD as a priority disease and attitudes toward regulation. Two concepts from the organisational management literature framed the study: citizenship behaviour where actions of individuals support the collective good (but are not explicitly recognised as such) and peer to peer monitoring (where individuals evaluate otherās behaviour). Farmers from two BVD control schemes in the UK participated in the study: Orkney Livestock Association BVD Eradication Scheme and Norfolk and Suffolk Cattle Breeders Association BVD Eradication Scheme. In total 162 farmers participated in the research (109 in-scheme and 53 out of scheme). The findings revealed that group helping and information sharing among scheme members was low with a positive BVD status subject to social censure. Peer monitoring in the form of gossip with regard to the animal health status of other farms was high. Interestingly, farmers across both schemes supported greater regulation with regard to animal health, largely due to the mistrust of fellow farmers following voluntary disease control measures. While group cohesiveness varied across the two schemes, without continued financial inducements, longer-term sustainability is questionabl
- ā¦