61 research outputs found
py4DSTEM: a software package for multimodal analysis of four-dimensional scanning transmission electron microscopy datasets
Scanning transmission electron microscopy (STEM) allows for imaging,
diffraction, and spectroscopy of materials on length scales ranging from
microns to atoms. By using a high-speed, direct electron detector, it is now
possible to record a full 2D image of the diffracted electron beam at each
probe position, typically a 2D grid of probe positions. These 4D-STEM datasets
are rich in information, including signatures of the local structure,
orientation, deformation, electromagnetic fields and other sample-dependent
properties. However, extracting this information requires complex analysis
pipelines, from data wrangling to calibration to analysis to visualization, all
while maintaining robustness against imaging distortions and artifacts. In this
paper, we present py4DSTEM, an analysis toolkit for measuring material
properties from 4D-STEM datasets, written in the Python language and released
with an open source license. We describe the algorithmic steps for dataset
calibration and various 4D-STEM property measurements in detail, and present
results from several experimental datasets. We have also implemented a simple
and universal file format appropriate for electron microscopy data in py4DSTEM,
which uses the open source HDF5 standard. We hope this tool will benefit the
research community, helps to move the developing standards for data and
computational methods in electron microscopy, and invite the community to
contribute to this ongoing, fully open-source project
Donor heart selection: the outcome of "unacceptable" donors
BACKGROUND: The decline in the number of suitable donor hearts has led to an increasing interest in the use of previously unacceptable donors. In the United Kingdom, if one centre declines a donor heart on medical grounds it may be offered to other centres. This multi-centre study aimed to evaluate the outcome of recipients of donor hearts considered medically unsuitable for transplantation by one centre that were used in other centres. METHODS: Between April 1998 and March 2003, ninety-three donor hearts (group A) were transplanted, after being considered medically unsuitable for transplantation by another centre. During the same period, 723 hearts (group B) were transplanted in the UK using donors not previously rejected. Data on the donors and recipients was obtained from the UK transplant database. Comparative analysis on the two groups was performed using SPSS 11.5 for Windows. RESULTS: The characteristics of recipients were similar in both groups. The main reasons for refusal of hearts are listed below. In most cases there was more than one reason for refusing the donor heart. We did not find significant differences in the post-operative mortality (up to 30 days), ICU and hospital stay and cardiac cause of death between the two groups. Kaplan-Meier survival curves showed no significant difference in the long-term survival, with Log Rank test = 0.30. CONCLUSION: This study demonstrates that some hearts declined on medical grounds by one centre can safely be transplanted and should be offered out nationally. The use of these hearts was useful to expand the scarce donor pool and there does not seem to be a justification for denying recipients this extra source of organs
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Expertise and the interpretation of computerized physiological data: implications for the design of computerized monitoring in neonatal intensive care
This paper presents the outcomes from a cognitive engineering project addressing the design problems of computerized monitoring in neonatal intensive care. Cognitive engineering is viewed, in this project, as a symbiosis between cognitive science and design practice. A range of methodologies has been used: interviews with neonatal staff, ward observations and experimental techniques. The results of these investigations are reported, focusing specifically on the differences between junior and senior physicians in their interpretation of monitored physiological data. It was found that the senior doctors made better use of the different knowledge sources available than the junior doctors. The senior doctors were able to identify more relevant physiological patterns and generated more and better inferences than did their junior colleagues. Expertise differences are discussed in the context of previous psychological research in medical expertise. Finally, the paper discusses the potential utility of these outcomes to inform the design of computerized decision support in neonatal intensive care
Chemoreceptor responsiveness at sea level does not predict the pulmonary pressure response to high altitude
The hypoxic ventilatory response (HVR) at sea level (SL) is moderately predictive of the
change in pulmonary artery systolic pressure (PASP) to acute normobaric hypoxia. However, because of
progressive changes in the chemoreflex control of breathing and acid-base balance at high altitude (HA),
HVR at SL may not predict PASP at HA. We hypothesized that resting peripheral oxyhemoglobin
saturation (SpO2) at HA would correlate better than HVR at SL to PASP at HA. In 20 participants at SL,
we measured normobaric, isocapnic HVR (L/min¡-%SpO2
-1) and resting PASP using echocardiography.
Both resting SpO2 and PASP measures were repeated on day 2 (n=10), days 4-8 (n=12), and 2-3 weeks
(n=8) after arrival at 5050m. These data were also collected at 5050m on life-long HA residents (Sherpa;
n=21). Compared to SL, SpO2 decreased from 98.6 to 80.5% (P<0.001), while PASP increased from
21.7 to 34.0mmHg (P<0.001) after 2-3 weeks at 5050m. Isocapnic HVR at SL was not related to SpO2
or PASP at any time point at 5050m (all P>0.05). Sherpa had lower PASP (P<0.01) than lowlanders on
days 4-8 despite similar SpO2. Upon correction for hematocrit, Sherpa PASP was not different from
lowlanders at SL, but lower than lowlanders at all HA time points. At 5050m, whilst SpO2 was not
related to PASP in lowlanders at any point (all R2=0.50), there was a weak relationship in the
Sherpa (R2=0.16; P=0.07). We conclude that neither HVR at SL nor resting SpO2 at HA correlates with
elevations in PASP at HA
Pravastatin for early-onset pre-eclampsia:a randomised, blinded, placebo-controlled trial
Objective: Women with pre-eclampsia have elevated circulating levels of soluble fms-like tyrosine kinase-1 (sFlt-1). Statins can reduce sFlt-1 from cultured cells and improve pregnancy outcome in animals with a pre-eclampsia-like syndrome. We investigated the effect of pravastatin on plasma sFlt-1 levels during pre-eclampsia. Design: Blinded (clinician and participant), proof of principle, placebo-controlled trial. Setting: Fifteen UK maternity units. Population: We used a minimisation algorithm to assign 62 women with early-onset pre-eclampsia (24 +0â31 +6 weeks of gestation) to receive pravastatin 40 mg daily (n = 30) or matched placebo (n = 32), from randomisation to childbirth. Primary outcome: Difference in mean plasma sFlt-1 levels over the first 3 days following randomisation. Results: The difference in the mean maternal plasma sFlt-1 levels over the first 3 days after randomisation between the pravastatin (n = 27) and placebo (n = 29) groups was 292 pg/ml (95% CI â1175 to 592; P = 0.5), and over days 1â14 was 48 pg/ml (95% CI â1009 to 913; P = 0.9). Women who received pravastatin had a similar length of pregnancy following randomisation compared with those who received placebo (hazard ratio 0.84; 95% CI 0.50â1.40; P = 0.6). The median time from randomisation to childbirth was 9 days [interquartile range (IQR) 5â14 days] for the pravastatin group and 7 days (IQR 4â11 days) for the placebo group. There were three perinatal deaths in the placebo-treated group and no deaths or serious adverse events attributable to pravastatin. Conclusions: We found no evidence that pravastatin lowered maternal plasma sFlt-1 levels once early-onset pre-eclampsia had developed. Pravastatin appears to have no adverse perinatal effects. Tweetable abstract: Pravastatin does not improve maternal plasma sFlt-1 or placental growth factor levels following a diagnosis of early preterm pre-eclampsia #clinicaltrial finds
Marine Shoreline Design Guidelines - Background and Phase 1 Case Studies
Shoreline armoring â the construction of bulkheads and seawalls â has become a significant issue for the Puget Sound region, with roughly one mile per year of new shoreline armoring. Armoring profoundly influences beaches, alters coastal processes and coastal ecology, and reduces the resilience of the coast to rising sea level. Alternative techniques to traditional hard armor have been applied in Puget Sound for decades, however, efforts to comprehensively monitor and compare different techniques and proper design are lacking. The Marine Shoreline Design Guidelines address this need through development of a manual on use of alternative techniques in Puget Sound. Phase 1 of this work involved detailed data collection from 25 individual sites representing five major design technique types, including traditional hard armor approaches. Our discussion of Phase 1 of the MSDG will include related information on the state of armoring on Puget Sound shorelines and the case study report that provides background data integral to the development of the guidelines document
Exploring the relationship between gambling, debt and financial management in Britain
The issue of how and why gamblers end up in debt has received comparatively little attention in the literature. Data from the 2007 Adult Psychiatric Morbidity Survey (APMS) revealed that although problem gamblers were more likely than non-problem gamblers to have forms of financial debt, just under two-thirds of problem gamblers (62%) reported having no debt. Using a qualitative approach, this study aimed to explore the issue from the perspective of gamblers themselves through interviews with 27 purposively sampled gamblers drawn from participants who took part in the APMS and the British Gambling Prevalence Survey 2010. Analysis, using the Framework method, suggested the existence of four kinds of gamblers categorized by their approach to gambling spending and their approach to their general spending: âcontrolled gamblersâ, âuncontrolled gamblersâ, âuncontrolled spendersâ and âchaotic spendersâ. Also proposed on the basis of these data is an ecological model which aims to capture the different levels of personal and environmental factors that influenced people's financial decisions, including cognitive factors, control and compulsion, normative spending, resource and financial management, and the credit environment. The implications for practice are also discussed
Guidance for the use of methadone for the treatment of opioid dependence in primary care.
⢠Methadone is an effective evidence based medication used for the treatment of opioid dependence.
⢠It is most effective when used as a maintenance agent at optimal dosing.
⢠Its primary function is to reduce (and eventually replace) illicit opioid use and in so doing, reduce harm and improve the health and psychological well-being of the patient
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