2,686 research outputs found
Water intoxication presenting as maternal and neonatal seizures: a case report.
Introduction
We present an unusual case of fitting in the mother and newborn child, and the challenges faced in the management of their hyponatraemia due to water intoxication.
Case presentation
A previously well 37-year-old, primigravid Caucasian woman presented with features mimicking eclampsia during labour. These included confusion, reduced consciousness and seizures but without a significant history of hypertension, proteinuria or other features of pre-eclampsia. Her serum sodium was noted to be low at 111 mmol/litre as was that of her newborn baby. She needed anti-convulsants with subsequent intubation to stop the fitting and was commenced on a hypertonic saline infusion with frequent monitoring of serum sodium. There is a risk of long-term neurological damage from central pontine myelinolysis if the hyponatraemia is corrected too rapidly. Mother and baby went on to make a full recovery without any long-term neurological complications.
Conclusion
There is little consensus on the treatment of life-threatening hyponatraemia. Previous articles have outlined several possible management strategies as well as their risks. After literature review, an increase in serum sodium concentration of no more than 8–10 mmol/litre in 24 hours is felt to be safe but can be exceeded with extreme caution if life-threatening symptoms do not resolve. Formulae exist to calculate the amount of sodium needed and how much hypertonic intravenous fluid will be required to allow safer correction. We hypothesise the possible causes of hyponatraemia in this patient and underline its similarity in symptom presentation to eclampsia
Erratum to: 25 Years of Self-organized Criticality: Concepts and Controversies
Introduced by the late Per Bak and his colleagues, self-organized criticality (SOC) has been one of the most stimulating concepts to come out of statistical mechanics and condensed matter theory in the last few decades, and has played a significant role in the development of complexity science. SOC, and more generally fractals and power laws, have attracted much comment, ranging from the very positive to the polemical. The other papers (Aschwanden et al. in Space Sci. Rev., 2014, this issue; McAteer et al. in Space Sci. Rev., 2015, this issue; Sharma et al. in Space Sci. Rev. 2015, in preparation) in this special issue showcase the considerable body of observations in solar, magnetospheric and fusion plasma inspired by the SOC idea, and expose the fertile role the new paradigm has played in approaches to modeling and understanding multiscale plasma instabilities. This very broad impact, and the necessary process of adapting a scientific hypothesis to the conditions of a given physical system, has meant that SOC as studied in these fields has sometimes differed significantly from the definition originally given by its creators. In Bak’s own field of theoretical physics there are significant observational and theoretical open questions, even 25 years on (Pruessner 2012). One aim of the present review is to address the dichotomy between the great reception SOC has received in some areas, and its shortcomings, as they became manifest in the controversies it triggered. Our article tries to clear up what we think are misunderstandings of SOC in fields more remote from its origins in statistical mechanics, condensed matter and dynamical systems by revisiting Bak, Tang and Wiesenfeld’s original papers
Coupled measurements of δ<sup>18</sup>O and δD of hydration water and salinity of fluid inclusions in gypsum from the Messinian Yesares Member, Sorbas Basin (SE Spain)
We studied one cycle (Cycle 6) of gypsum-marl deposition from the Messinian Yesares Member in Sorbas Basin, Spain. The objective was to reconstruct the changing environment of deposition and its relation to astronomically-forced climate change. The δ1818O and δD of gypsum hydration water (CaSO4•2H2O) and salinity of fluid inclusions were measured in the same samples to test if they record the composition of the mother fluid from which gypsum was precipitated. Water isotopes are highly correlated with fluid inclusion salinity suggesting the hydration water has not exchanged after formation. The relatively low water isotope values and fluid inclusion salinities indicate a significant influence of meteoric water, whereas δ34S, δ18OSO4 26 and 87Sr/86Sr support a dominant marine origin for the gypsum deposits. The discrepancy between water and elemental isotope signatures can be reconciled if meteoric water dissolved previously deposited marine sulfates supplying calcium and sulfate ions to the basin which maintained gypsum saturation. This recycling process accounts for the marine δ34S, δ18OSO4 and 87Sr/86Sr signatures, whereas the low δ18O and δD values of gypsum hydration water and fluid inclusion salinities reflect the influence of freshwater.
The cyclic deposition of gypsum and marl in the Yesares Member has previously been interpreted to reflect changing climate related to Earth’s precession cycle. We demonstrate that the δ18O, δD and salinity of the parent brine increased from low values at the base of Cycle 6 to a maximum in the massive gypsum palisade, and decreased again to lower values in the supercones at the
top of the cycle. This pattern, together with changes in mineralogy (calcite-dolomite-gypsum), is consistent with a precession-driven change in climate with wettest conditions (summer insolation maxima) associated with the base of the calcium carbonate marls and driest conditions (summer insolation minima) during formation of the gypsum palisade.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement n. 339694 (Water Isotopes of Hydrated Minerals) to D. A. Hodell.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.epsl.2015.07.07
Chemical weathering outputs from the flood plain of the Ganga
Transport of sediment across riverine flood plains contributes a significant but poorly constrained
fraction of the total chemical weathering fluxes from rapidly eroding mountain belts which has impor-
tant implications for chemical fluxes to the oceans and the impact of orogens on long term climate. We
report water and bedload chemical analyses from the Ganges flood-plain, a major transit reservoir of
sediment from the Himalayan orogen. Our data comprise six major southern tributaries to the Ganga,
31 additional analyses of major rivers from the Himalayan front in Nepal, 79 samples of the Ganga
collected close to the mouth below the Farakka barrage every two weeks over three years and 67 water
and 8 bedload samples from tributaries confined to the Ganga flood plain,. The flood plain tributaries
are characterised by a shallow d 18 O - dD array, compared to the meteoric water line, with a low dD excess
from evaporative loss from the flood plain which is mirrored in the higher dD excess of the mountain
rivers in Nepal. The stable-isotope data confirms that the waters in the flood plain tributaries are domi-
nantly derived from flood plain rainfall and not by redistribution of waters from the mountains. The
flood plain tributaries are chemically distinct from the major Himalayan rivers. They can be divided
into two groups. Tributaries from a small area around the Kosi river have 87 Sr/ 86 Sr ratios > 0.75 and
molar Na/Ca ratios as high as 6. Tributaries from the rest of the flood plain have 87 Sr/ 86 Sr ratios <0.74
and most have Na/Ca ratios <1. One sample of the Gomti river and seven small adjacent tributaries
have elevated Na concentrations likely caused by dissolution of Na carbonate salts. The compositions
of the carbonate and silicate components of the sediments were determined from sequential leaches of
floodplain bedloads and these were used to partition the dissolved cation load between silicate and car-
bonate sources. The 87 Sr/ 86 Sr and Sr/Ca ratios of the carbonate inputs were derived from the ace-
tic-acid leach compositions and silicate Na/Ca and 87 Sr/ 86 Sr ratios derived from silicate residues from
leaching. Modelling based on the 87 Sr/ 86 Sr and Sr/Ca ratios of the carbonate inputs and 87 Sr/ 86 Sr ratios
of the silicates indicates that the flood plain waters have lost up to 70% of their Ca (average ~ 50%) to
precipitation of secondary calcite which is abundant as a diagenetic cement in the flood plain sedi-
ments. 31% of the Sr, 8% of the Ca and 45% of the Mg are calculated to be derived from silicate miner-
als. Because of significant evaporative loss of water across the flood plain, and in the absence of hy-
drological data for flood plain tributaries, chemical weathering fluxes from the flood plain are best
calculated by mass balance of the Na, K, Ca, Mg, Sr, SO 4 and 87 Sr/ 86 Sr compositions of the inputs,
comprising the flood plain tributaries, Himalayan rivers and southern rivers, with the chemical dis-
charge in the Ganga at Farakka. The calculated fluxes from the flood plain for Na, K, Ca and Mg are
within error of those estimated from changes in sediment chemistry across the flood plain (Lupker et
al., 2012, Geochemica Cosmochimica Acta). Flood plain weathering supplies between 33 and 48% of
the major cation and Sr fluxes and 58% of the alkalinity flux carried by the Ganga at Farakka which
compares with 24% supplied by Himalayan rivers and 18% by the southern tributaries
An inductive force sensor for in-shoe plantar normal and shear load measurement
Diabetic foot ulcers (DFUs) are a severe global public health issue. Plantar normal and shear load are believed to play an important role in the development of foot ulcers and could be a valuable indicator to improve assessment of DFUs. However, despite their promise, plantar load measurements currently have limited clinical application, primarily due to the lack of reliable measurement techniques particularly for shear load measurements. In this paper we report on the design and evaluation of a novel tri-axis force sensor to measure both normal and shear load on the foot’s plantar surface simultaneously. The sensor consists of a group of inductive sensing coils above which a conductive target is placed on a hyperelastic elastomer.
Movement of the target under load affects the coil inductances which are measured and digitized by an embedded system. Using a computational finite element model, we investigated the influence of sensing coil form and configuration on sensor performance.
A sensor configured with four-square coils and maximal turns provided the best performance for plantar load measurements. A prototype was fabricated and calibrated using a neural network to map the non-linear relationship between the sensor output
and the applied tri-axis load. Experimental evaluation indicates that the tri-axis sensor can effectively detect shear load of �16
N and normal load up to 105 N (RMS errors: 1.05 N and 1.73 N respectively) with a high performance. Overall, this sensor
provides a promising basis for plantar normal and shear load measurement which are crucial for improved assessment of DFU
A Review of Wearable Sensor Systems to Monitor Plantar Loading in the Assessment of Diabetic Foot Ulcers
Diabetes is highly prevalent throughout the world and imposes a high economic cost on countries at all income levels. Foot ulceration is one devastating consequence of diabetes, which can lead to amputation and mortality. Clinical assessment of diabetic foot ulcer (DFU) is currently subjective and limited, impeding effective diagnosis, treatment and prevention. Studies have shown that pressure and shear stress at the plantar surface of the foot plays an important role in the development of DFUs. Quantification of these could provide an improved means of assessment of the risk of developing DFUs. However, commercially-available sensing technology can only measure plantar pressures, neglecting shear stresses and thus limiting their clinical utility. Research into new sensor systems which can measure both plantar pressure and shear stresses are thus critical.
Our aim in this paper is to provide the reader with an overview of recent advances in plantar pressure and stress sensing and offer insights into future needs in this critical area of healthcare. Firstly, we use current clinical understanding as the basis to define requirements for wearable sensor systems capable of assessing DFU. Secondly, we review the fundamental sensing technologies employed in this field and investigate the capabilities of the resultant wearable systems, including both commercial and research-grade equipment. Finally, we discuss research trends, ongoing challenges and future opportunities for improved sensing technologies to monitor plantar loading in the diabetic foot
A systematic review and narrative synthesis of footwear and orthotic devices used in the management of ankle haemarthrosis and haemarthropathy in haemophilia
Introduction
Haemarthrosis is a clinical feature of haemophilia leading to haemarthropathy. The ankle joint is most commonly affected, resulting in significant pain, disability and a reduction in health-related quality of life. Footwear and orthotic devices are effective in other diseases that affect the foot and ankle, such as rheumatoid arthritis, but little is known about their effect in haemophilia.
Aims
To review the efficacy and effectiveness of footwear and orthotic devices in the management of ankle joint haemarthrosis and haemarthropathy in haemophilia.
Methods
A systematic literature review was conducted. Two review authors independently screened studies for inclusion and appraised methodological quality using Joanna Briggs Institute Critical Appraisal checklists. A narrative analysis was undertaken.
Results
Ten studies involving 271 male participants were eligible for inclusion. All studies were quasi-experimental; three employed a within-subject design. Two studies included an independent comparison or control group. A range of footwear and orthotic devices were investigated. Limited evidence from non-randomised studies suggested that footwear and orthotic devices improve the number of ankle joint bleeding episodes, gait parameters, and patient-reported pain.
Conclusion
This review demonstrates a lack of robust evidence regarding the efficacy and effectiveness of footwear and orthotic devices in the management of ankle joint haemarthrosis and haemarthropathy in haemophilia. Methodological heterogeneities and limitations with the study designs, small sample sizes and limited follow-up of participants exist. Future studies utilising randomised designs, larger sample sizes, long-term follow-up, and validated patient-reported outcome measures are needed to inform the clinical management of ankle joint haemarthrosis and haemarthropathy
Decline in health-related quality of life and foot and ankle patient reported outcomes measures in patients with haemophilia and ankle haemarthropathy
Background
Haemophilia is an X-linked recessive genetic disorder characterised by bleeding within soft tissue and joints. The ankle is disproportionally affected by haemarthropathy when compared to the elbows and knees; reported as the most affected joints in patients with haemophilia. Despite advances in treatment, patients still report ongoing pain and disability, however, the impact has not been evaluated, nor has the effect on health-related quality of life (HRQoL) or foot and ankle patient-reported outcome measures (PROMs). The primary aim of this study was to establish the impact of ankle haemarthropathy in patients with severe and moderate haemophilia A and B. Secondly to identify the clinical outcomes associated with a decline in HRQoL and foot and ankle PROMs.
Methods
A cross-sectional multi-centre questionnaire study was conducted across 18 haemophilia centres in England, Scotland and Wales with a recruitment target of 245 participants. The HAEMO-QoL-A and Manchester-Oxford Foot Questionnaire (MOXFQ) (foot and ankle) with total and domain scores measured impact on HRQOL and foot and ankle outcomes. Demographics, clinical characteristics, ankle haemophilia joint health scores, multi-joint haemarthropathy and Numerical Pain Rating Scales (NPRS) of “ankle pain over the past six months” were collected as a measure of chronic ankle pain.
Results
A total of 243 of 250 participants provided complete data. HAEMO-QoL-A and MOXFQ (foot and ankle) total and index scores indicated worse HRQoL with total scores ranging from a mean of 35.3 to 35.8 (100 best-health) and 50.5 to 45.8 (0 best-health) respectively. NPRS (mean (SD)) ranged from 5.0 (2.6) to 5.5 (2.5), with median (IQR) ankle haemophilia joint health score of 4.5 (1 to 12.5) to 6.0 (3.0 to 10.0) indicating moderate to severe levels of ankle haemarthropathy. Ankle NPRS over six months and inhibitor status were associated with decline in outcome.
Conclusions
HRQoL and foot and ankle PROMs were poor in participants with moderate to severe levels of ankle haemarthropathy. Pain was a major driver for decline in HRQoL and foot and ankle PROMs and use of NPRS has the potential to predict worsening HRQoL and PROMs at the ankle and other affected joints
Developing a manually annotated clinical document corpus to identify phenotypic information for inflammatory bowel disease
<p>Abstract</p> <p>Background</p> <p>Natural Language Processing (NLP) systems can be used for specific Information Extraction (IE) tasks such as extracting phenotypic data from the electronic medical record (EMR). These data are useful for translational research and are often found only in free text clinical notes. A key required step for IE is the manual annotation of clinical corpora and the creation of a reference standard for (1) training and validation tasks and (2) to focus and clarify NLP system requirements. These tasks are time consuming, expensive, and require considerable effort on the part of human reviewers.</p> <p>Methods</p> <p>Using a set of clinical documents from the VA EMR for a particular use case of interest we identify specific challenges and present several opportunities for annotation tasks. We demonstrate specific methods using an open source annotation tool, a customized annotation schema, and a corpus of clinical documents for patients known to have a diagnosis of Inflammatory Bowel Disease (IBD). We report clinician annotator agreement at the document, concept, and concept attribute level. We estimate concept yield in terms of annotated concepts within specific note sections and document types.</p> <p>Results</p> <p>Annotator agreement at the document level for documents that contained concepts of interest for IBD using estimated Kappa statistic (95% CI) was very high at 0.87 (0.82, 0.93). At the concept level, F-measure ranged from 0.61 to 0.83. However, agreement varied greatly at the specific concept attribute level. For this particular use case (IBD), clinical documents producing the highest concept yield per document included GI clinic notes and primary care notes. Within the various types of notes, the highest concept yield was in sections representing patient assessment and history of presenting illness. Ancillary service documents and family history and plan note sections produced the lowest concept yield.</p> <p>Conclusion</p> <p>Challenges include defining and building appropriate annotation schemas, adequately training clinician annotators, and determining the appropriate level of information to be annotated. Opportunities include narrowing the focus of information extraction to use case specific note types and sections, especially in cases where NLP systems will be used to extract information from large repositories of electronic clinical note documents.</p
A Portable Insole System to Simultaneously Measure Plantar Pressure and Shear Stress
Objective: This work aims to develop an integrated in-shoe measurement system to fully record plantar loading, including both pressure and shear stresses, across the full contact surface. These data are vital to help understand and prevent the development of complex conditions such as Diabetic Foot Ulcers (DFUs), a worldwide healthcare challenge. Currently no systems exist to reliably record these data.
Methods: In this paper we report development of the SLIPS ('Shear Load Inductive Plantar Sensing') system which integrates 64 tri-axial force sensors into a flexible insole to measure plantar loading. SLIPS translates our multi-axis inductive load sensing technology into a full sensory array embedded within an insole and complete with communication and power bus. A pilot study evaluates the system in three healthy participants during walking.
Results: Testing shows that the SLIPS system is well tolerated by participants and can operate under dynamic gait loading regimes. The pilot study reveals the complex nature of plantar loading. Regions of peak pressure loading align with anatomical landmarks and shear loading forms a significant component of the overall load. Notably, regions of peak shear and pressure are not necessarily collocated or present in unison.
Conclusion: This work highlights the need for in-shoe plantar measurement systems like SLIPS capable of mapping both pressure and shear load, and their use to improve understanding of how these factors relate to clinical conditions like DFU.
Significance: SLIPS represents the first in-shoe measurement system capable of measuring both pressure and shear across the whole plantar surface in unison
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