11,351 research outputs found
Comparison of human uterine cervical electrical impedance measurements derived using two tetrapolar probes of different sizes
BACKGROUND
We sought to compare uterine cervical electrical impedance spectroscopy measurements employing two probes of different sizes, and to employ a finite element model to predict and compare the fraction of electrical current derived from subepithelial stromal tissue.
METHODS
Cervical impedance was measured in 12 subjects during early pregnancy using 2 different sizes of the probes on each subject.
RESULTS
Mean cervical resistivity was significantly higher (5.4 vs. 2.8 Ωm; p < 0.001) with the smaller probe in the frequency rage of 4–819 kHz. There was no difference in the short-term intra-observer variability between the two probes. The cervical impedance measurements derived in vivo followed the pattern predicted by the finite element model.
CONCLUSION
Inter-electrode distance on the probes for measuring cervical impedance influences the tissue resistivity values obtained. Determining the appropriate probe size is necessary when conducting clinical studies of resistivity of the cervix and other human tissues
Human response to vibration in residential environments (NANR209), technical report 2: measurement of response
Based on a review of the literature and the best practice guidance available, a social survey questionnaire was developed to measure residents’ self-reported annoyance and to provide data suitable for establishing exposure-response relationships between levels of annoyance and levels of vibration. The development of the questionnaire was influenced by a number of previous studies such as: the social survey questionnaire developed for the NANR172 Pilot Study of this research (Defra, 2007); best practice guidelines for the development of socio-acoustic surveys issued by ICBEN and presented in the current International Standard (Fields et al., 2001; ISO/TS 15666:2003); the Nordtest Method (2001) for the development of socio-vibration surveys, and a peer review of the social survey questionnaire by international experts in the field. In order to avoid influencing responses and reasons for participation in the research, the survey was introduced as a survey of neighbourhood satisfaction. The questionnaire design, through the use of sections, enables new sections to be added to the questionnaire so that specific vibration sources can be investigated in more depth. In addressing the ‘response’ component in the ‘exposure-response’ relationship, the questionnaire was designed to yield interval-level measurement data suitable for analysis with vibration measurement data via two response scales: the five-point semantic and the eleven-point numerical scales. This decision was largely founded upon the ability of the two scales to meet the criteria established by ICBEN (Fields et al., 2001) for socio-acoustic survey design. Detailed procedures were documented, following the field trial of the questionnaire, in terms of the role of the interviewer, the recording of information and the transfer of the data to the relevant database for subsequent analysis and to inform the vibration team responsible for the ‘exposure’ component of this research project
Three Dimensional Electrical Impedance Tomography
The electrical resistivity of mammalian tissues varies widely and is correlated with physiological
function. Electrical impedance tomography (EIT) can be used to probe such variations in vivo, and offers a
non-invasive means of imaging the internal conductivity distribution of the human body. But the
computational complexity of EIT has severe practical limitations, and previous work has been restricted to
considering image reconstruction as an essentially two-dimensional problem. This simplification can limit
significantly the imaging capabilities of EIT, as the electric currents used to determine the conductivity variations will not in general be confined to a two-dimensional plane. A few studies have attempted three-dimensional EIT image reconstruction, but have not yet succeeded in generating images of a quality suitable for clinical applications. Here we report the development of a three-dimensional EIT system with greatly improved imaging capabilities, which combines our 64-electrode data-collection apparatus with customized matrix inversion techniques. Our results demonstrate the practical potential of EIT for clinical applications, such as lung or brain imaging and diagnostic screening
Evaluation of turbulence closure models under spilling and plunging breakers in the surf zone
Turbulence closure models are evaluated for application to spilling and plunging breakers in the surf zone using open source computational fluid dynamics software. A new library of turbulence models for application to multiphase flows has been developed and is assessed for numerical efficiency and accuracy by comparing against existing laboratory data for surface elevation, velocity and turbulent kinetic energy profiles. Out of the models considered, it was found that, overall, the best model is the nonlinear k - ϵ model. The model is also shown to exhibit different turbulent characteristics between the different breaker types, consistent with experimental data
Rectification from Radially-Distorted Scales
This paper introduces the first minimal solvers that jointly estimate lens
distortion and affine rectification from repetitions of rigidly transformed
coplanar local features. The proposed solvers incorporate lens distortion into
the camera model and extend accurate rectification to wide-angle images that
contain nearly any type of coplanar repeated content. We demonstrate a
principled approach to generating stable minimal solvers by the Grobner basis
method, which is accomplished by sampling feasible monomial bases to maximize
numerical stability. Synthetic and real-image experiments confirm that the
solvers give accurate rectifications from noisy measurements when used in a
RANSAC-based estimator. The proposed solvers demonstrate superior robustness to
noise compared to the state-of-the-art. The solvers work on scenes without
straight lines and, in general, relax the strong assumptions on scene content
made by the state-of-the-art. Accurate rectifications on imagery that was taken
with narrow focal length to near fish-eye lenses demonstrate the wide
applicability of the proposed method. The method is fully automated, and the
code is publicly available at https://github.com/prittjam/repeats.Comment: pre-prin
Clinician-reported changes in octreotide prescribing for malignant bowel obstruction as a result of an adequately powered phase III study: A transnational, online survey
© The Author(s) 2018. Background: Translating research evidence into clinical practice often has a long lag time. Aim: To determine the impact of a phase III randomised controlled trial on palliative care clinicians’ self-reported practice change. Design: Online survey about use of octreotide in managing inoperable malignant bowel obstruction due to cancer or its treatments distributed in November 2016, 2 years after the first publication of the study in a peer-reviewed journal. Demographic, self-reported practice and the reasons underpinning this were collected. Responses were aggregated to ‘practice modified’ or ‘practice not modified’. A multinomial regression model explored predictors of practice change. Setting: Members of the Australian New Zealand Society of Palliative Medicine. Results: Response rate was 20.8% (106/509): 55.6% were aged >50 years, 56.5% were female and 77% had previously prescribed octreotide for this clinical indication. Out of 106 respondents, 52 (49.1%) indicated modified practice (60.9% of those who had previously prescribed octreotide in this setting). In those who reported practice change, most frequently octreotide was now used when other therapies failed; for not changing practice, ‘more confirmatory evidence was needed’ was most often cited. In the regression model, older age (clinician age = 50–59 years; relative risk = 0.147; 95% confidence interval = 0.024–0.918; p = 0.04) and having practices with lower proportions of people treated with octreotide (0%–20%; relative risk = 0.039; 95% confidence interval = 0.002–0.768; p = 0.033) predicted greater self-reported practice change. Conclusion: Clinician-reported change in practice in the survey is seen in the majority of respondents. This suggests that there is a cohort of ‘early adopters’ within palliative care practice as new evidence becomes available
Variation in advanced stage at diagnosis of lung and female breast cancer in an English region 2006-2009
This is the final published version. Available from Springer Nature via the DOI in this record.Background: Understanding variation in stage at diagnosis can inform interventions to improve the timeliness of diagnosis for patients with different cancers and characteristics. Methods: We analysed population-based data on 17 836 and 13 286 East of England residents diagnosed with (female) breast and lung cancer during 2006-2009, with stage information on 16 460 (92%) and 10 435 (79%) patients, respectively. Odds ratios (ORs) of advanced stage at diagnosis adjusted for patient and tumour characteristics were derived using logistic regression. Results :We present adjusted ORs of diagnosis in stages III/IV compared with diagnosis in stages I/II. For breast cancer, the frequency of advanced stage at diagnosis increased stepwise among old women (ORs: 1.21, 1.46, 1.68 and 1.78 for women aged 70-74, 75-79, 80-84 and ≥85, respectively, compared with those aged 65-69, P<0.001). In contrast, for lung cancer advanced stage at diagnosis was less frequent in old patients (ORs: 0.82, 0.74, 0.73 and 0.66, P<0.001). Advanced stage at diagnosis was more frequent in more deprived women with breast cancer (OR: 1.23 for most compared with least deprived, P=0.002), and in men with lung cancer (OR: 1.14, P=0.011). The observed patterns were robust to sensitivity analyses approaches for handling missing stage data under different assumptions. Conclusion: Interventions to help improve the timeliness of diagnosis of different cancers should be targeted at specific age groups. © 2012 Cancer Research UK All rights reserved
Associations between nut consumption and health vary between omnivores, vegetarians, and vegans
Regular nut consumption is associated with reduced risk factors for chronic disease; however, most population-based studies lack consideration of effect modification by dietary pattern. The UK Women’s Cohort Study (UKWCS) provides an ideal opportunity to examine relationships between nut consumption and chronic disease risk factors in a large sample with diverse dietary patterns. Nut and nutrient intake from 34,831 women was estimated using a food frequency questionnaire among self-identified omnivores, vegetarians and vegans. In this cross-sectional analysis, higher nut consumption was associated with lower body weight (difference between highest and lowest consumption categories from adjusted model: 6.1kg; 95%CI: 4.7, 7.6) body mass index (BMI, 2.4 units difference; 95%CI: 1.9, 2.9), and waist circumference (2.6cm difference; 95%CI: 1.4, 3.8) (all P for linear trend < 0.001). Higher nut consumption was also associated with reduced prevalence of high cholesterol and high blood pressure; having a history of heart attack, diabetes and gallstones; and markers of diet quality (all adjusted P for linear trend ≤0.011). Higher nut consumption appeared overall to be associated with greater benefits amongst omnivores compared to vegetarians and vegans. Findings support existing literature around beneficial effects of nut consumption and suggest that benefits may be larger among omnivores. Nut promotion strategies may have the highest population impact by specifically targeting this group
Mitigating systematic error in topographic models for geomorphic change detection: Accuracy, precision and considerations beyond off‐nadir imagery
Unmanned aerial vehicles (UAVs) and structure-from-motion photogrammetry enable detailed quantification of geomorphic change. However, rigorous precision-based change detection can be compromised by survey accuracy problems producing systematic topographic error (e.g. 'doming'), with error magnitudes greatly exceeding precision estimates. Here, we assess survey sensitivity to systematic error, directly correcting topographic data so that error magnitudes align more closely with precision estimates. By simulating conventional grid-style photogrammetric aerial surveys, we quantify the underlying relationships between survey accuracy, camera model parameters, camera inclination, tie point matching precision and topographic relief, and demonstrate a relative insensitivity to image overlap. We show that a current doming-mitigation strategy of using a gently inclined ( 0 center dot 3 m, representing accuracy issues an order of magnitude greater than precision-based error estimates. For higher-relief topography, and for nadir-imaging surveys of the lower-relief topography, systematic error was <0 center dot 09 m. Modelling and subtracting the systematic error directly from the topographic data successfully reduced error magnitudes to values consistent with twice the estimated precision. Thus, topographic correction can provide a more robust approach to uncertainty-based detection of event-scale geomorphic change than designing surveys with small off-nadir camera inclinations and, furthermore, can substantially reduce ground control requirements. (c) 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Lt
Socio-demographic inequalities in stage of cancer diagnosis: Evidence from patients with female breast,lung, colon, rectal, prostate, renal, bladder, melanoma, ovarian and endometrial cancer
This is the final published version. Available from Oxford University Press via the DOI in this record.Background: Understanding socio-demographic inequalities in stage at diagnosis can inform priorities for cancer control. Patients and methods: We analysed data on the stage at diagnosis of East of England patients diagnosed with any of 10 common cancers, 2006-2010. Stage information was available on 88 657 of 98 942 tumours (89.6%). Results: Substantial socio-demographic inequalities in advanced stage at diagnosis (i.e. stage III/IV) existed for seven cancers, but their magnitude and direction varied greatly by cancer: advanced stage at diagnosis was more likely for older patients with melanoma but less likely for older patients with lung cancer [odds ratios for 75-79 versus 65-69 1.60 (1.38-1.86) and 0.83 (0.77-0.89), respectively]. Deprived patients were more likely to be diagnosed in advanced stage for melanoma, prostate, endometrial and (female) breast cancer: odds ratios (most versus least deprived quintile) from 2.24 (1.66-3.03) for melanoma to 1.31 (1.15-1.49) for breast cancer. In England, elimination of sociodemographic inequalities in stage at diagnosis could decrease the number of patients with cancer diagnosed in advanced stage by 5600 annually. Conclusions: There are substantial socio-demographic inequalities in stage at diagnosis for most cancers. Earlier detection interventions and policies can be targeted on patients at higher risk of advanced stage diagnosis. ©The Author 2012.National Institute for Health Research (NIHR
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