The feedback between fluid migration and rock deformation in mid-crustal shear zones is acknowledged as being critical for earthquake nucleation, the initiation of subduction zones and the formation ...of mineral deposits. The importance of this poorly understood feedback is further highlighted by evidence for shear-zone-controlled advective flow of fluids in the ductile lower crust and the recognition that deformation-induced grain-scale porosity is a key to large-scale geodynamics. Fluid migration in the middle crust cannot be explained in terms of classical concepts. The environment is considered too hot for a dynamic fracture-sustained permeability as in the upper crust, and fluid pathways are generally too deformed to be controlled by equilibrium wetting angles that apply to hotter, deeper environments. Here we present evidence that mechanical and chemical potentials control a syndeformational porosity generation in mid-crustal shear zones. High-resolution synchrotron X-ray tomography and scanning electron microscopy observations allow us to formulate a model for fluid migration in shear zones where a permeable porosity is dynamically created by viscous grain-boundary sliding, creep cavitation, dissolution and precipitation. We propose that syndeformational fluid migration in our 'granular fluid pump' model is a self-sustained process controlled by the explicit role of the rate of entropy production of the underlying irreversible mechanical and chemical microprocesses. The model explains fluid transfer through the middle crust, where strain localization in the creep regime is required for plate tectonics, the formation of giant ore deposits, mantle degassing and earthquake nucleation. Our findings provide a key component for the understanding of creep instabilities in the middle crust.
Type 2 diabetes mellitus is the result of a combination of impaired insulin secretion with reduced insulin sensitivity of target tissues. There are an estimated 150 million affected individuals ...worldwide, of whom a large proportion remains undiagnosed because of a lack of specific symptoms early in this disorder and inadequate diagnostics. In this study, NMR-based metabolomic analysis in conjunction with multivariate statistics was applied to examine the urinary metabolic changes in two rodent models of type 2 diabetes mellitus as well as unmedicated human sufferers. The db/db mouse and obese Zucker (fa/fa) rat have autosomal recessive defects in the leptin receptor gene, causing type 2 diabetes. 1H-NMR spectra of urine were used in conjunction with uni- and multivariate statistics to identify disease-related metabolic changes in these two animal models and human sufferers. This study demonstrates metabolic similarities between the three species examined, including metabolic responses associated with general systemic stress, changes in the TCA cycle, and perturbations in nucleotide metabolism and in methylamine metabolism. All three species demonstrated profound changes in nucleotide metabolism, including that of N-methylnicotinamide and N-methyl-2-pyridone-5-carboxamide, which may provide unique biomarkers for following type 2 diabetes mellitus progression.
Three types of Au sources in ferricrete Au deposits. In Type 1, most Au is sourced from the underlying mineralization. In Type 2, Au is sourced from both underlying and external mineralization. In ...Type 3, all Au is sourced from external mineralization.
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•Ferricrete Au deposits occur downslope from saprolite hills and near inset-valleys.•Large Au dispersion haloes in ferricrete may contain a viable ore grade deposit.•Gold dispersion in ferricrete is by physical, biological and chemical processes.•Cortices, cracks and voids are the main hosts of Au.•The source of Au in ferricrete is proximal.
Secondary mineral deposits have played an important role in the global mineral resource economy for over 50 years, with lateritic Au, Al, Fe and Ni deposits having a significant input to global metal production and reserves. In the Yilgarn Craton of Western Australia, a deeply weathered mantle is commonly capped with 2–10 m of lateritic residuum (residual lateritic gravels and duricrust) and/or ferricrete (Fe oxide-cemented sediment), which formed under seasonally humid tropical and sub-tropical climates during the Cenozoic. The principal constituents of these units are goethite, hematite, maghemite, kaolinite and quartz. They are commonly overlain by younger, 2–10 m thick transported cover, deposited under later semi-arid conditions. Both ferricrete and lateritic residuum may host exploitable secondary gold deposits, typically small (<500,000 ounces) and of low grade (<1–5 g/t Au). The lateritic residuum deposits overlie weathered and fresh primary mineralization, whereas ferricrete deposits overlie uneconomic primary mieralization or barren saprolite and bedrock. Despite numerous studies, many questions remain about the behaviour and evolution of Au in the complex polygenetic systems that form lateritic residuum and ferricrete. In particular, why is it difficult to locate significant primary mineralization associated with highly Au-anomalous ferricrete? Understanding the mechanisms of enrichment of Au and pathfinder elements in ferricrete will assist future discovery. Accordingly, to obtain conclusive evidence for processes of anomaly formation, a combination of detailed field observations with state-of-the-art microscopy have been conducted at three of the larger deposits (Moolart Well, Mt Gibson and Bulchina). The aim of this review is to integrate these recent results with the results of earlier studies to trace the path of Au and pathfinder elements and associated dispersion processes in the ferricrete environment.
Motivated by the challenge of capturing complex hierarchical chemical detail in natural material from a wide range of applications, the Maia detector array and integrated realtime processor have been ...developed to acquire X-ray fluorescence images using X-ray Fluorescence Microscopy (XFM). Maia has been deployed initially at the XFM beamline at the Australian Synchrotron and more recently, demonstrating improvements in energy resolution, at the P06 beamline at Petra III in Germany. Maia captures fine detail in element images beyond 100 M pixels. It combines a large solid-angle annular energy-dispersive 384 detector array, stage encoder and flux counter inputs and dedicated FPGA-based real-time event processor with embedded spectral deconvolution. This enables high definition imaging and enhanced trace element sensitivity to capture complex trace element textures and place them in a detailed spatial context. Maia hardware and software methods provide per pixel correction for dwell, beam flux variation, dead-time and pileup, as well as off-line parallel processing for enhanced throughput. Methods have been developed for real-time display of deconvoluted SXRF element images, depth mapping of rare particles and the acquisition of 3D datasets for fluorescence tomography and XANES imaging using a spectral deconvolution method that tracks beam energy variation.
We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin ...sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5Hz frequency range, and de-amplification of higher frequencies (>2.5–10Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.
•2015 Gorkha sequence recorded on five strong motion and two high-rate GPS stations on soil and rock sites in Kathmandu.•Soil-rock spectral ratios reveal low frequency amplification, high frequency deamplification.•Shaking intensity controlled by 3D basin effects, anelastic site response, and source properties.
Background An update of evidence-based guidelines concerning liberation from mechanical ventilation is needed as new evidence has become available. The American College of Chest Physicians (CHEST) ...and the American Thoracic Society (ATS) have collaborated to provide recommendations to clinicians concerning liberation from the ventilator. Methods Comprehensive evidence syntheses, including meta-analyses, were performed to summarize all available evidence relevant to the guideline panel’s questions. The evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach, and the results were summarized in evidence profiles. The evidence syntheses were discussed and recommendations developed and approved by a multidisciplinary committee of experts in mechanical ventilation. Results Recommendations for three population, intervention, comparator, outcome (PICO) questions concerning ventilator liberation are presented in this document. The guideline panel considered the balance of desirable (benefits) and undesirable (burdens, adverse effects, costs) consequences, quality of evidence, feasibility, and acceptability of various interventions with respect to the selected questions. Conditional (weak) recommendations were made to use inspiratory pressure augmentation in the initial spontaneous breathing trial (SBT) and to use protocols to minimize sedation for patients ventilated for more than 24 h. A strong recommendation was made to use preventive noninvasive ventilation (NIV) for high-risk patients ventilated for more than 24 h immediately after extubation to improve selected outcomes. The recommendations were limited by the quality of the available evidence. Conclusions The guideline panel provided recommendations for inspiratory pressure augmentation during an initial SBT, protocols minimizing sedation, and preventative NIV, in relation to ventilator liberation.
Pancreatic ductal adenocarcinoma is an aggressive malignancy with a high mortality rate. Proper determination of the extent of disease on imaging studies at the time of staging is one of the most ...important steps in optimal patient management. Given the variability in expertise and definition of disease extent among different practitioners as well as frequent lack of complete reporting of pertinent imaging findings at radiologic examinations, adoption of a standardized template for radiology reporting, using universally accepted and agreed on terminology for solid pancreatic neoplasms, is needed. A consensus statement describing a standardized reporting template authored by a multi-institutional group of experts in pancreatic ductal adenocarcinoma that included radiologists, gastroenterologists, and hepatopancreatobiliary surgeons was developed under the joint sponsorship of the Society of Abdominal Radiologists and the American Pancreatic Association. Adoption of this standardized imaging reporting template should improve the decision-making process for the management of patients with pancreatic ductal adenocarcinoma by providing a complete, pertinent, and accurate reporting of disease staging to optimize treatment recommendations that can be offered to the patient. Standardization can also help to facilitate research and clinical trial design by using appropriate and consistent staging by means of resectability status, thus allowing for comparison of results among different institutions.
Purpose Our aim was to determine the role of end-of-induction (EOI) minimal residual disease (MRD) assessment in the identification and stratification of induction failure in patients with pediatric ...acute lymphoblastic leukemia (ALL) and to identify genetic abnormalities that drive disease in these patients. Patients and Methods Analysis included 3,113 patients who were treated in the Medical Research Council UKALL2003 multicenter randomized trial (NCT00222612) between 2003 and 2011. MRD was measured by using standardized real-time quantitative PCR. Median follow-up was 5 years 9 months. Results Fifty-nine patients (1.9%) had morphologic induction failure with 5-year event-free survival (EFS) of 50.7% (95% CI, 37.4 to 64.0) and 5-year overall survival of 57.7% (95% CI, 44.2 to 71.2). Of these, a small proportion of patients with M2 marrow (6 of 44) and a low EOI MRD level (< 0.01%) had 5-year EFS of 100%. Conversely, among patients with morphologic remission 2.3% (61 of 2,633) had high MRD (≥ 5%) and 5-year EFS of 47.0% (95% CI, 32.9 to 61.1), which was similar to those with morphologic induction failure. Redefining induction failure to include morphologic induction failure and/or MRD ≥ 5% identified 3.9% (120 of 3,133 patients) of the trial cohort with 5-year EFS of 48.0% (95% CI, 39.3 to 58.6). Induction failure (morphologic or MRD ≥ 5%) occurred most frequently in T-ALL (10.1%; 39 of 386 T-ALL cases) and B-other ALL, that is, lacking established chromosomal abnormalities (5.6%; 43 of 772 B-other cases). Genetic testing within the B-other group revealed the presence of PDGFRB gene fusions, particularly EBF1-PDGFRB, in almost one third of B-other ALL cases. Conclusion Integration of EOI MRD level with morphology identifies induction failure more precisely than morphology alone. Prevalence of EBF1-PDGFRB fusions in this group highlights the importance of genetic screening to identify abnormalities that may be targets for novel agents.
The fundamental parameter method for quantitative SXRF and PIXE analysis and imaging using the dynamic analysis method is extended to model the changing X-ray yields and detector sensitivity with ...angle across large detector arrays. The method is implemented in the GeoPIXE software and applied to cope with the large solid-angle of the new Maia 384 detector array and its 96 detector prototype developed by CSIRO and BNL for SXRF imaging applications at the Australian and NSLS synchrotrons. Peak-to-background is controlled by mitigating charge-sharing between detectors through careful optimization of a patterned molybdenum absorber mask. A geological application demonstrates the capability of the method to produce high definition elemental images up to ∼100
M pixels in size.
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