Shale adhesion force measurements via atomic force microscopy

Wettability of sedimentary rock surface is an essential parameter that defines oil recovery and production rates of a reservoir. The discovery of wettability alteration in reservoirs, as well as complications that occur in analysis of heterogeneous sample, such as shale, for instance, have prompted scientists to look for the methods of wettability assessment at nanoscale. At the same time, bulk techniques, which are commonly applied, such as USBM (United States Bureau of Mines) or Amott tests, are not sensitive enough in cases with mixed wettability of rocks as they provide average wettability values of a core plug. Atomic Force Microscopy (AFM) has been identified as one of the methods that allow for measurement of adhesion forces between cantilever and sample surface in an exact location at nanoscale. These adhesion forces can be used to estimate wettability locally. Current research, however, shows that the correlation is not trivial. Moreover, adhesion force measurement via AFM has not been used extensively in studies with geological samples yet. In this study, the adhesion force values of the cantilever tip interaction with quartz inclusion on the shale sample surface, have been measured using the AFM technique. The adhesion force measured in this particular case was equal to the capillary force of water meniscus, formed between the sample surface and the cantilever tip. Experiments were conducted with a SiconG cantilever with (tip radius of 5 nm). The adhesion forces between quartz grain and cantilever tip were equal to 56.5 ± 5 nN. Assuming the surface of interaction to be half spherical, the adhesion force per area was 0.36 ± 0.03 nN/nm2. These measurements and results acquired at nano-scale will thus create a path towards much higher accuracy-wettability measurements and consequently better reservoir-scale predictions and improved underground operations

Distribution of Metals in the Termite Tumulitermes tumuli (Froggatt): Two Types of Malpighian Tubule Concretion Host Zn and Ca Mutually Exclusively

The aim of this study was to determine specific distribution of metals in the termite Tumulitermes tumuli (Froggatt) and identify specific organs within the termite that host elevated metals and therefore play an important role in the regulation and transfer of these back into the environment. Like other insects, termites bio-accumulate essential metals to reinforce cuticular structures and utilize storage detoxification for other metals including Ca, P, Mg and K. Previously, Mn and Zn have been found concentrated in mandible tips and are associated with increased hardness whereas Ca, P, Mg and K are accumulated in Malpighian tubules. Using high resolution Particle Induced X-Ray Emission (PIXE) mapping of whole termites and Scanning Electron Microscope (SEM) Energy Dispersive X-ray (EDX) spot analysis, localised accumulations of metals in the termite T. tumuli were identified. Tumulitermes tumuli was found to have proportionally high Mn concentrations in mandible tips. Malpighian tubules had significant enrichment of Zn (1.6%), Mg (4.9%), P (6.8%), Ca (2.7%) and K (2.4%). Synchrotron scanning X-ray Fluorescence Microprobe (XFM) mapping demonstrated two different concretion types defined by the mutually exclusive presence of Ca and Zn. In-situ SEM EDX realisation of these concretions is problematic due to the excitation volume caused by operating conditions required to detect minor amounts of Zn in the presence of significant amounts of Na. For this reason, previous researchers have not demonstrated this surprising finding

Mineralogy and geochemistry of atypical reduction spheroids from the Tumblagooda Sandstone, Western Australia

Funding Information: This research was supported by a CSIRO Mineral Resources studentship, a Curtin University student scholarship and a Minerals Research Institute of Western Australia scholarship. The editors of Sedimentology and three anonymous reviewers are acknowledged for their assistance in improving the manuscript. We would also like to thank Mike Paxman and the Parks and Wildlife Service for permission to sample in Kalbarri National Park. Finally, the authors would like to pay tribute to the memory of Professor Nigel Trewin, whose work laid much of the foundation for this study and many others on the Tumblagooda Sandstone.Peer reviewedPostprin

Using metaphorical techniques in focus groups to uncover mothers' feelings about family meals

Traditional nutrition education has not been shown to consistently produce behavior change. While it has been suggested that using emotion-based messages may be a better way to influence nutrition behavior change, this has not been well tested. Producing emotion-based messages is a multi-step process that begins with exploring subconscious barriers to behavior change rather than the more obvious and typically reported barriers. The purpose of this research was to uncover the emotional reasons, sometimes referred to as emotional pulse points, for mothers' choosing or not choosing to have more family meals. This would then serve as the first step to developing emotion-based messages promoting the benefits of family meals. Five focus group interviews were conducted with 51 low-income Black (n=28) and white (n=23) mothers. Metaphorical techniques were used to determine underlying feelings toward family and family meals. Discussions were video-taped, transcribed, and manually analyzed using a content-driven, immersion/crystallization approach to qualitative data analysis. Four themes emerged around the definition of family: acceptance, sharing, chaos, and protective/loyal. Some mothers felt mealtime was merely obligatory, and described it as stressful. Some reported a preference for attending to their own needs instead of sitting down with their children, while others felt that mealtime should be used to interact with and educate children and felt guilty when they were not able to provide family meals. Three themes emerged around feelings towards having or not having family meals: unimportant, important, and guilty. When explored further, mothers indicated that using the feeling of guilt to encourage family meals might be effective. Data obtained are being used to develop innovative, emotion-based messages that will be tested for effectiveness in promoting family meals

CO2 saturated brine injected into fractured shale: An X-ray micro-tomography in-situ analysis at reservoir conditions

Fracture morphology and permeability are key factors in enhanced gas recovery (EOR) and Carbon Geo-storage (CCS) in shale gas reservoirs as they determine production and injection rates. However, the exact effect of CO2-saturated (live) brine on shale fracture morphology, and how the permeability changes during live brine injection and exposure is only poorly understood. We thus imaged fractured shale samples before and after live brine injection in-situ at high resolution in 3D via X-ray micro-computed tomography. Clearly, the fractures’ aperture and connectivity increased after live brine injection

Modelling the effects of environmental heterogeneity within the lung on the tuberculosis life-cycle

Funding: This work was supported by the Medical Research Council [grant number MR/P014704/1] and the PreDiCT-TB consortium (IMI Joint undertaking grant agreement number 115337, resources of which are composed of financial contribution from the European Union’s Seventh Framework Programme (FP7/2007-2013) and EF-PIA companies’ in kind contribution.Progress in shortening the duration of tuberculosis (TB) treatment is hampered by the lack of a predictive model that accurately reflects the diverse environment within the lung. This is important as TB has been shown to produce distinct localisations to different areas of the lung during different disease stages, with the environmental heterogeneity within the lung of factors such as air ventilation, blood perfusion and oxygen tension believed to contribute to the apical localisation witnessed during the post-primary form of the disease. Building upon our previous model of environmental lung heterogeneity, we present a networked metapopulation model that simulates TB across the whole lung, incorporating these notions of environmental heterogeneity across the whole TB life-cycle to show how different stages of the disease are influenced by different environmental and immunological factors. The alveolar tissue in the lung is divided into distinct patches, with each patch representing a portion of the total tissue and containing environmental attributes that reflect the internal conditions at that location. We include populations of bacteria and immune cells in various states, and events are included which determine how the members of the model interact with each other and the environment. By allowing some of these events to be dependent on environmental attributes, we create a set of heterogeneous dynamics, whereby the location of the tissue within the lung determines the disease pathological events that occur there. Our results show that the environmental heterogeneity within the lung is a plausible driving force behind the apical localisation during post-primary disease. After initial infection, bacterial levels will grow in the initial infection location at the base of the lung until an adaptive immune response is initiated. During this period, bacteria are able to disseminate and create new lesions throughout the lung. During the latent stage, the lesions that are situated towards the apex are the largest in size, and once a post-primary immune-suppressing event occurs, it is the uppermost lesions that reach the highest levels of bacterial proliferation. Our sensitivity analysis also shows that it is the differential in blood perfusion, causing reduced immune activity towards the apex, which has the biggest influence of disease outputs.Publisher PDFPeer reviewe

Hepatic and renal end-organ damage in the Fontan circulation: a report from the Australian and New Zealand Fontan Registry

Background: Hepatic and renal dysfunction have been observed in survivors of the Fontan procedure, however their incidence and associated factors remain poorly defined. Methods: A total of 152 participants from a Registry of 1528 patients underwent abdominal ultrasound, transient elastography (FibroScan), serum fibrosis score (FibroTest), in vivo Tc-99m DTPA measurement of glomerular filtration rate (mGFR), and urine albumin-creatinine ratio (ACR). Results: Mean age and time since Fontan were 19.8 ± 9.3 and 14.1 ± 7.6 years, respectively. Features suggestive of hepatic fibrosis were observed on ultrasound in 87/143 (61%) and no patient was diagnosed with hepatocellular carcinoma. FibroScan median kPa was ≥10 in 117/133 (88%), ≥15 in 75/133 (56%), and ≥20 in 41/133 (31%). Fifty-four patients (54/118, 46%) had a FibroTest score ≥0.49 (equivalent to ≥F2 fibrosis). FibroTest score correlated with FibroScan value (r = 0.24, p = 0.015) and ACR (r = 0.29, p = 0.002), and patients with ultrasound features of hepatic fibrosis had a higher FibroScan median kPa (19.5 vs 15.4, p = 0.002). Renal impairment was mild (mGFR 60–89 ml/min/1.73 m) in 46/131 (35%) and moderate (mGFR 30–59 ml/min/1.73 m) in 3/131 (2%). Microalbuminuria was detected in 52/139 participants (37%). By multivariable analysis, time since Fontan was associated with increased FibroScan median kPa (β = 0.89, 95% CI 0.54–1.25, p = 0.002) and decreased mGFR (β = −0.77, 95% CI −1.29–0.24, p = 0.005). Conclusions: In the second decade after Fontan hepatic and renal structure and function are abnormal in a significant number of patients: close to 60% have ultrasonographic evidence of structural hepatic abnormalities, 46% have elevated serum hepatic fibrosis scores, and 57% have either reduced glomerular filtration rate or microalbuminuria. Hepatic and renal function should be monitored for potential impacts on outcomes after Fontan completion

Innate activation of human primary epithelial cells broadens the host response to Mycobacterium tuberculosis in the airways

Early events in the human airways determining whether exposure to Mycobacterium tuberculosis (Mtb) results in acquisition of infection are poorly understood. Epithelial cells are the dominant cell type in the lungs, but little is known about their role in tuberculosis. We hypothesised that human primary airway epithelial cells are part of the first line of defense against Mtb-infection and contribute to the protective host response in the human respiratory tract. We modelled these early airway-interactions with human primary bronchial epithelial cells (PBECs) and alveolar macrophages. By combining in vitro infection and transwell co-culture models with a global transcriptomic approach, we identified PBECs to be inert to direct Mtb-infection, yet to be potent responders within an Mtb-activated immune network, mediated by IL1β and type I interferon (IFN). Activation of PBECs by Mtb-infected alveolar macrophages and monocytes increased expression of known and novel antimycobacterial peptides, defensins and S100-family members and epithelial-myeloid interactions further shaped the immunological environment during Mtb-infection by promoting neutrophil influx. This is the first in depth analysis of the primary epithelial response to infection and offers new insights into their emerging role in tuberculosis through complementing and amplifying responses to Mtb

Social deprivation and asthma

This study was conducted to see whether children living in socially deprived areas were more likely than other children to be admitted to hospital for asthma, and, if so, whether their excess risk was attributable to a higher prevalence of asthma or poorer treatment. Hospital admission rates for asthma were obtained for Cardiff electoral wards and compared with the Townsend indices of deprivation. A survey of respiratory symptoms was conducted in schoolchildren; prevalence of symptoms was compared with Townsend index and asthma admission rate for the schools' catchment areas. Asthma admissions were strongly correlated with Townsend indices at all ages. The prevalence of reported asthma and various degrees of wheeze in the schools was not significantly correlated with Townsend index or hospital admission rate in the corresponding areas. The presence of a smoker in the house was strongly associated with Townsend index and admission rate; children whose houses contained a smoker were more likely than others to have wheezed in the past year and to have disturbed nights due to wheezing. There was a non-significant negative association between Townsend index and regular use of inhaled steroids. The relationship between hospital admission for asthma and social deprivation is not explained by variations in prevalence, but it may be attributable to the aggravation of symptoms by active or passive smoking, and perhaps also to differences in management