bluuebunny/crossref_metadata_2025 huggingface dataset:
An Extension of the Low Reduced Frequency Model for Viscothermal Acoustic Propagation Within Waveguides
Authors: Sambuc Clément , Lielens Gregory , Coyette Jean-Pierre
Published: September 2013

Inside micro cavities, specific dissipative mechanisms influencing acoustic wave propagation occur due to viscous and heat-conducting nature of the fluid. This work focuses on a possible extension of the so called “Low Reduced Frequency” model for acoustic wave propagation in a thermoviscous fluid. This extension is built starting from geometrical and physical assumptions (boundary layer theory, straight waveguides) and consists in the incorporation of a stationary laminar and subsonic mean flow. The resulting equivalent fluid model provides a new damping coefficient which depends on the Mach number, the shear and thermal wave numbers and the cross-sectional profiles of axial velocity and temperature. The main application area is the study of acoustic attenuation within automotive catalytic converters or also thin fluid layers like cooling systems in small electronic devices. This formulation has been implemented for a simple one dimensional thin tube. Convergence to the original model in the absence of mean flow has been reached and comparisons with variational solutions given by Peat show good agreements.
Sound Quality in Urban Environments and its Relationship With Acoustic Parameters
Authors: Barrigón Morillas Juan M. , Gómez Escobar Valentín , Rey Gozalo Guillermo , Vílchez-Gómez Rosendo , Méndez Sierra Juan Antonio , Trujillo Carmona José , Prieto Gajardo Carlos , Carmona del Río F. Javier
Published: September 2013

Different urban environments were analyzed acoustically using recordings obtained with binaural techniques of recording and reproduction. Measurements were carried out in different urban locations in Spain that possess a range of acoustical characteristics. The perception of pleasantness/unpleasantness as described by the inhabitants of these urban environments was examined in terms of its relationship with two psychoacoustic parameters (loudness and sharpness) as well as the traditional measures of equivalent sound level (dB and dBA). These relationships were analyzed using both a verbal and a numerical scale. Highly significant correlations were found between the perception of an environment and the acoustical parameters characterizing that environment.
Lightweight Design Analysis Based on a Coupled Structural-Acoustic Model for Rectangular Enclosures
Authors: Du Yu , Zhang Jun , Li Weidong , Hu Ping
Published: September 2013

As an effort to reduce energy consumption and hazardous emissions, lightweight design has become more and more important for new vehicle developments. Substituting conventional steel material with other low-density materials in building vehicle structures is one typical approach for lightweight designs. To investigate the influence of the structural weight change on the noise, vibration and harshness (NVH) performance, this study presents a structural-acoustic coupled model of a rectangular shaped cavity enclosed by 1 or 2 flexible panels. Using this modal, parametric studies aiming at reducing the total structural weight and simultaneously improving the NVH performance are conducted. For the case of a single flexible panel subject to a point force excitation, it is found that substituting the heavier steel panel with a lighter Al panel may actually reduce the sound radiation inside the cavity at the low frequency range. On the other hand, at higher frequencies, the noise radiation level is roughly inversely proportional to the material density. For the case with dual flexible panels, although it is predicted that the two panels are weakly coupled through the acoustic cavity at most frequencies, the noise level may still be reduced at a lighter structural weight in certain cases.
Procedures for Estimating Environmental Impact From Railway Induced Vibration: A Review
Authors: Avillez Jorge , Frost Matthew , Cawser Steve , Skinner Chris , El-Hamalawi Ashraf , Shields Paul
Published: September 2013

Railway induced ground-borne vibration is among the most common and widespread sources of perceptible environmental vibration. It can give rise to discomfort and disturbance, adversely impacting on human activity and the operation of sensitive equipment. The rising demand for building new railway lines or upgrading existing lines in order to meet increasing transit flows has furthered the need for adequate vibration assessment tools during the planning and design stages. In recent years many studies in the fields of rail and ground dynamics have encouraged many prediction techniques giving rise to a wide variety of procedures for estimating vibration on buildings. Each method shows potential for application at different levels of complexity and applicability to varying circumstances. From the perspective of railway environmental impact assessment, this paper reviews some relevant prediction techniques, assessing their degree of suitability for practical engineering application by weighting their methodology (i.e. considerations and requirements) against practicality and precision. The review suggests that not all procedures are practicable (e.g. the attainment of representative parameters needed to run the procedures) whilst others predicate on assumptions, which revealed to be too relaxed resulting in insufficient accuracy; however, a combination of methods may provide the necessary balance.
On the Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures: A Comparison of ABAQUS and ANSYS
Authors: Kirkegaard Poul Henning , Andersen Lars Vabbersgaard , Dickow Kristoffer Ahrens
Published: September 2013

During the last couple of years, there has been an increasing focus on the vibro-acoustic performance of built environments due to increasing requirements in building codes regarding impact and airborne sound transmission. Hence, development of efficient and accurate methods for prediction of sound in such buildings is important. In the low-frequency range, prediction of sound and vibration in building structures may be achieved by finite-element analysis (FEA). The aim of this paper is to compare the two commercial codes ABAQUS and ANSYS for FEA of an acoustic-structural coupling in a timber, lightweight panel structure. For this purpose, modal analyses are carried out employing a fully coupled model of sound waves within an acoustic medium and vibrations in the structural part. The study concerns the frequency range 50–250 Hz.
A New Method of Curve Fitting for Calculation of Reverberation Time From Impulse Responses With Insufficient Length
Authors: Özgenel Çağlar Fırat , Sorguç Arzu Gönenç
Published: September 2013

Most of the room acoustics evaluation parameters are calculated from the energy decay curve obtained from the room impulse response. Schroeder’s backwards integration method is one of the most commonly used methods to obtain room impulse response. Although, the method holds its validity since 1964 and used extensively, obtaining room impulse response with sufficient length to observe total energy decay requires high computational cost especially in highly reverberant rooms. In such cases, present acoustical analysis and simulation tools either use data extrapolation and linear fitting methods or they fail to provide any reliable output. Hence, in order to provide reliable data based on such an impulse response, high computational cost and effort are required. In this context, a modification for acoustical analysis methods based on impulse response is proposed, comprising a linear fitting algorithm and extrapolation together with data culling. Proposed method is based on the linear energy decay assumption of Schroeder and ideal energy decay according to global reverberation time estimates. Method is proposed for diffuse field conditions regardless of the length of room impulse response. Validity of the proposed method is checked via a developed room acoustics tool, namely RAT, and case studies conducted with the mentioned tool.
Virtual Sensing in Local Active Suppression on Pressure Fluctuations for Controlling Flow-Induced Vibration in Hard Disk Drives
Authors: Min Hequn , Huang Xiaoyang , Zhang Qide
Published: September 2013

Numerical simulations are presented on a feedback active control strategy for flow-induced off-track vibration of the head gimbals assembly (HGA) supporting the slider in hard disk drives, through suppressing pressure fluctuations around the HGA. A virtual sensing method is employed to enable the feedback signal changeable from pressure fluctuations at the physical sensor position to those at single “virtual sensor” positions closely around the HGA or a spatial average of pressure fluctuations along an HGA surface. Based on a linear control methodology, performance of the proposed active control strategy with different feedback signals has been investigated in two-dimensional simulations, where a physical pressure sensor and a pressure actuator are assumed on the inner-surface of the HDD cover to detect the pressure fluctuations and to actuate active pressure oscillations into HDD space respectively. The results show effective control on the HGA off-track vibration when the feedback signal is configured to minimize pressure fluctuations at specific positions closely around the HGA, such as the wake region. It is also shown that satisfying control effect can be achieved on the HGA off-track vibration in the global spectrum when the feedback signal is configured to minimize the spatial average of pressure fluctuations along the upper surface of the HGA.
Vibrational and Acoustical Analysis of Trussed Railroad Bridge Under Moving Loads
Authors: Costley R. Daniel , Diaz-Alvarez Henry , McKenna Mihan H.
Published: September 2013

A Finite Element model has been developed for a Pratt truss railroad bridge located at Ft. Leonard Wood, MO. This model was used to investigate the vibration responses of a bridge under vehicle loading. Modeling results have been obtained for a single axle with two wheels traversing the bridge at different speeds. The current model does not include the effects of vehicle suspension. Superposition of multiple axles has been used to represent a locomotive transiting the bridge. The output of the vibration response was used as an input to an acoustic FE model to determine which vibrational modes radiate infrasound. The vibration and acoustic models of the railroad bridge will be reviewed, and results from the analysis will be presented. Measurements from an accelerometer mounted on the bridge agree reasonably well with model results. Infrasound could potentially be used to remotely provide information on the capacity and number of the vehicles traversing the bridge and to monitor the bridge for significant structural damage.
Temperature stability of high-resistivity GaN buffer layers grown by metalorganic chemical vapor deposition
Authors: Polyakov Alexander Y. , Smirnov N. B. , Kozhukhova E. A. , Osinsky Andrei V. , Pearton Stephen J.
Published: September 2013

Nominally undoped GaN films were grown by metalorganic chemical vapor deposition under three different conditions, namely (1) “standard” growth conditions with growth temperature of 1000 °C and growth rate of 1 μm/h, (2) slightly reduced growth temperature of 975 °C, and (3) standard temperature, but higher growth rate of 2.5 μm/h. The standard sample had a net donor density <1015 cm−3, while the two other samples were semi-insulating, with sheet resistivity ∼1014 Ω/square and the Fermi level pinned at Ec−0.8 eV for the low temperature growth and at Ec−0.9 eV for the high growth rate conditions. The photoconductivity spectra of both of these latter samples show the presence of centers with optical threshold near 1.35 eV commonly attributed to C interstitials and centers with optical threshold near 2.7–2.8 eV and 3 eV often associated with C-related defects. However, no signals that could be attributed to substitutional C acceptors and C donors were detected. Current relaxation spectroscopy revealed deep traps with activation energies 0.2, 0.25, 045, and 0.8 eV. Annealing at 800 °C increased the concentration of these traps. The changes in resistivity induced by annealing in the high-growth rate sample were much stronger than for the low-temperature sample. The authors also observed a strong suppression of the yellow luminescence band intensity in the “standard” sample after annealing, as opposed to a slight increase of this band intensity in the two semi-insulating samples. The role of compensation by native defects and by deep levels related to carbon in the observed changes is discussed.
A framework to measure myocardial extracellular volume fraction using dual‐phase low dose CT images
Authors: Liu Yixun , Liu Songtao , Nacif Marcelo S. , Sibley Christopher T. , Bluemke David A. , Summers Ronald M. , Yao Jianhua
Published: September 2013

Purpose:

Myocardial extracellular volume fraction (ECVF) is a surrogate imaging biomarker of diffuse myocardial fibrosis, a hallmark of pathologic ventricular remodeling. Low dose cardiac CT is emerging as a promising modality to detect diffuse interstitial myocardial fibrosis due to its fast acquisition and low radiation; however, the insufficient contrast in the low dose CT images poses great challenge to measure ECVF from the image.

Methods:

To deal with this difficulty, the authors present a complete ECVF measurement framework including a point‐guided myocardial modeling, a deformable model‐based myocardium segmentation, nonrigid registration of pre‐ and post‐CT, and ECVF calculation.

Results:

The proposed method was evaluated on 20 patients by two observers. Compared to the manually delineated reference segmentations, the accuracy of our segmentation in terms of true positive volume fraction (TPVF), false positive volume fraction (FPVF), and average surface distance (ASD), were 92.18% ± 3.52%, 0.31% ± 0.10%, 0.69 ± 0.14 mm, respectively. The interobserver variability measured by concordance correlation coefficient regarding TPVF, FPVF, and ASD were 0.95, 0.90, 0.94, respectively, demonstrating excellent agreement. Bland‐Altman method showed 95% limits of agreement between ECVF at CT and ECVF at MR.

Conclusions:

The proposed framework demonstrates its efficiency, accuracy, and noninvasiveness in ECVF measurement and dramatically advances the ECVF at cardiac CT toward its clinical use.
Mineralization in calcified plaque is like that of cortical bone—Further evidence from ultrashort echo time (UTE) magnetic resonance imaging of carotid plaque calcification and cortical bone
Authors: Du Jiang , Peterson Michael , Kansal Nikhil , Bydder Graeme M. , Kahn Andrew
Published: September 2013

Purpose:

This study aims to investigate carotid plaque calcification (CPC) using two‐dimensional (2D) and 3D ultrashort echo time (UTE) magnetic resonance imaging (MRI) sequences and compare T1, T2*, water concentration, and bone mineral density (BMD) of CPC with those of cortical bone.

Methods:

Twelve carotid plaque specimens and eight tibial cortical bone samples were imaged with UTE sequences. Adiabatic inversion recovery prepared UTE (IR‐UTE) acquisitions were used for T2* measurement. Saturation recovery prepared UTE acquisitions were used for T1 measurement. Water concentration was measured by comparing signal from CPC and bone with that from a phantom. BMD was measured withμ CT. Conventional gradient echo and fast spin echo images were also acquired for comparison.

Results:

Our studies show that CPC and cortical bone have similar T1 and BMD values but different T2* and water concentration. For CPC T2*s ranged from 0.31 to 3.87 ms, T1s ranged from 114 to 332 ms, water concentrations ranged from 6.4% to 17.6%, and BMD ranged from 977 to 1319 mg/ml. For cortical bone T2*s ranged from 0.33 to 0.45 ms, T1s ranged from 198 to 254 ms, water concentrations ranged from 24.7% to 33.8%, and mineral densities ranged from 970 to 1287 mg/ml. On average CPC shows about 5% longer T1, 5% lower BMD, 440% longer T2*, and 130% lower water concentration when compared to human cortical bone.

Conclusions:

CPC bears remarkable similarities with cortical bone in terms of BMD and T1. CPC shows a higher mean T2* and a lower mean water concentration.
Resetting a Lagging Body Clock
Authors: Ferrarelli Leslie K.
Published: September 2013

Inhibiting a kinase activated in response to light may accelerate the body’s adjustment to circadian rhythm disruptions.
Down-Regulation of Autophagy-Related Protein 5 (ATG5) Contributes to the Pathogenesis of Early-Stage Cutaneous Melanoma
Authors: Liu He , He Zhaoyue , von Rütte Thomas , Yousefi Shida , Hunger Robert E. , Simon Hans-Uwe
Published: September 2013

Down-regulation of autophagy-related protein 5 decreases autophagy and contributes to tumorigenesis in human melanoma cells and patients’ tumors.
Engineering a Replication-Competent, Propagation-Defective Middle East Respiratory Syndrome Coronavirus as a Vaccine Candidate
Authors: Almazán Fernando , DeDiego Marta L. , Sola Isabel , Zuñiga Sonia , Nieto-Torres Jose L. , Marquez-Jurado Silvia , Andrés German , Enjuanes Luis
Published: September 2013

Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging coronavirus infecting humans that is associated with acute pneumonia, occasional renal failure, and a high mortality rate and is considered a threat to public health. The construction of a full-length infectious cDNA clone of the MERS-CoV genome in a bacterial artificial chromosome is reported here, providing a reverse genetics system to study the molecular biology of the virus and to develop attenuated viruses as vaccine candidates. Following transfection with the cDNA clone, infectious virus was rescued in both Vero A66 and Huh-7 cells. Recombinant MERS-CoVs (rMERS-CoVs) lacking the accessory genes 3, 4a, 4b, and 5 were successfully rescued from cDNA clones with these genes deleted. The mutant viruses presented growth kinetics similar to those of the wild-type virus, indicating that accessory genes were not essential for MERS-CoV replication in cell cultures. In contrast, an engineered mutant virus lacking the structural E protein (rMERS-CoV-ΔE) was not successfully rescued, since viral infectivity was lost at early passages. Interestingly, the rMERS-CoV-ΔE genome replicated after cDNA clone was transfected into cells. The infectious virus was rescued and propagated in cells expressing the E protein in
trans
, indicating that this virus was replication competent and propagation defective. Therefore, the rMERS-CoV-ΔE mutant virus is potentially a safe and promising vaccine candidate to prevent MERS-CoV infection.

IMPORTANCE
Since the emergence of MERS-CoV in the Arabian Peninsula during the summer of 2012, it has already spread to 10 different countries, infecting around 94 persons and showing a mortality rate higher than 50%. This article describes the development of the first reverse genetics system for MERS-CoV, based on the construction of an infectious cDNA clone inserted into a bacterial artificial chromosome. Using this system, a collection of rMERS-CoV deletion mutants has been generated. Interestingly, one of the mutants with the E gene deleted was a replication-competent, propagation-defective virus that could only be grown in the laboratory by providing E protein in
trans
, whereas it would only survive a single virus infection cycle
in vivo
. This virus constitutes a vaccine candidate that may represent a balance between safety and efficacy for the induction of mucosal immunity, which is needed to prevent MERS-CoV infection.
Proton-Dependent Gating and Proton Uptake by Wzx Support O-Antigen-Subunit Antiport Across the Bacterial Inner Membrane
Authors: Islam Salim T. , Eckford Paul D. W. , Jones Michelle L. , Nugent Timothy , Bear Christine E. , Vogel Christian , Lam Joseph S.
Published: September 2013

Wzx flippases are crucial for bacterial cell surface polysaccharide assembly as they transport undecaprenyl pyrophosphate-linked sugar repeat units from the cytoplasmic to the periplasmic leaflets of the inner membrane (IM) for final assembly. Our recently reported three-dimensional (3D) model structure of Wzx from
Pseudomonas aeruginosa
PAO1 (Wzx

Pa

) displayed a cationic internal vestibule and functionally essential acidic amino acids within transmembrane segment bundles. Herein, we examined the intrinsic transport function of Wzx

Pa

following its purification and reconstitution in phospholipid liposomes. Wzx

Pa

was capable of mediating anion flux, consistent with its cationic interior. This flux was electrogenic and modified by extraliposomal pH. Mutation of the above-mentioned acidic residues (E61, D269, and D359) reduced proton (H
+
)-modified anion flux, showing the role of these amino acid side chains in H
+
-dependent transport. Wzx also mediated acidification of the proteoliposome interior in the presence of an outward anion gradient. These results indicate H
+
-dependent gating and H
+
uptake by Wzx

Pa

and allow for the first H
+
-dependent antiport mechanism to be proposed for lipid-linked oligosaccharide translocation across the bacterial IM.

IMPORTANCE
Many bacterial cell surface polysaccharides that are important for survival and virulence are synthesized at the periplasmic leaflet of the inner membrane (IM) using precursors produced in the cytoplasm. Wzx flippases are responsible for translocation of lipid-linked sugar repeat units across the IM and had been previously suggested to simply facilitate passive substrate diffusion. Through our characterization of purified Wzx in a reconstitution system described herein, we have observed protein-dependent intrinsic transport producing a change in the electrical potential of the system, with H
+
identified as the coupling ion. These results provide the first evidence for coupled (i.e., secondary active) transport by these proteins and, in conjunction with structural data, allow for an antiport mechanism to be proposed for the directed transport of lipid-linked sugar substrates across the IM. These findings bring our understanding of lipid-linked polysaccharide transporter proteins more in line with the efflux pumps to which they are evolutionarily related.
Biliary stent migration causing perforation of the caecum and chronic abdominal pain
Authors: Jones Michael , George Bethan , Jameson John , Garcea Giuseppe
Published: September 2013

We report a case of biliary stent migration causing perforation of the caecum and presenting as chronic abdominal pain. The case was managed by colonoscopic removal of the stent.
Simultaneous bilateral spontaneous pneumothoraces: a case of occupational asthma
Authors: Khan Waseem Asrar , Curl-Roper Thomas , Helm Jenifer , Houghton Catherine
Published: September 2013

Simultaneous bilateral spontaneous pneumothoraces (SBSP) are uncommon. This report presents the case of a previously well 19-year-old man with a diagnosis of SBSP and symptoms suggestive of occupational asthma. Despite bilateral bullectomy and pleurodesis using a video-assisted thoracoscopic surgical technique, the pneumothorax reoccurred unilaterally and open surgery was performed. This case illustrates a rare condition of bilateral pneumothoraces presenting as a first presentation of occupational asthma and the issues surrounding its management.
The proportion of clinically relevant alarms decreases as patient clinical severity decreases in intensive care units: a pilot study
Authors: Inokuchi Ryota , Sato Hajime , Nanjo Yuko , Echigo Masahiro , Tanaka Aoi , Ishii Takeshi , Matsubara Takehiro , Doi Kent , Gunshin Masataka , Hiruma Takahiro , Nakamura Kensuke , Shinohara Kazuaki , Kitsuta Yoichi , Nakajima Susumu , Umezu Mitsuo , Yahagi Naoki
Published: September 2013

Objectives

To determine (1) the proportion and number of clinically relevant alarms based on the type of monitoring device; (2) whether patient clinical severity, based on the sequential organ failure assessment (SOFA) score, affects the proportion of clinically relevant alarms and to suggest; (3) methods for reducing clinically irrelevant alarms in an intensive care unit (ICU).

Design

A prospective, observational clinical study.

Setting

A medical ICU at the University of Tokyo Hospital in Tokyo, Japan.

Participants

All patients who were admitted directly to the ICU, aged ≥18 years, and not refused active treatment were registered between January and February 2012.

Methods

The alarms, alarm settings, alarm messages, waveforms and video recordings were acquired in real time and saved continuously. All alarms were annotated with respect to technical and clinical validity.

Results

18 ICU patients were monitored. During 2697 patient-monitored hours, 11 591 alarms were annotated. Only 740 (6.4%) alarms were considered to be clinically relevant. The monitoring devices that triggered alarms the most often were the direct measurement of arterial pressure (33.5%), oxygen saturation (24.2%), and electrocardiogram (22.9%). The numbers of relevant alarms were 12.4% (direct measurement of arterial pressure), 2.4% (oxygen saturation) and 5.3% (electrocardiogram). Positive correlations were established between patient clinical severities and the proportion of relevant alarms. The total number of irrelevant alarms could be reduced by 21.4% by evaluating their technical relevance.

Conclusions

We demonstrated that (1) the types of devices that alarm the most frequently were direct measurements of arterial pressure, oxygen saturation and ECG, and most of those alarms were not clinically relevant; (2) the proportion of clinically relevant alarms decreased as the patients’ status improved and (3) the irrelevance alarms can be considerably reduced by evaluating their technical relevance.
PP45 Developing Recommendations to Improve the Effectiveness of Multidisciplinary Team Meetings for Patients with Chronic Diseases
Authors: Nic a’ Bháird C , Wallace I , Xanthopoulou P , Barber J , Clarke A , Lanceley A , Ardron D , Harris M , Blazeby J , Ferlie E , Gibbs S , King M , Livingston G , Michie S , Prentice A , Raine R
Published: September 2013

Background

Multidisciplinary team meetings (MDMs) have been endorsed by the Department of Health as the core model for managing chronic diseases. It is believed that MDMs ensure higher quality decision making and improved outcomes. However, the evidence underpinning the development of MDMs is not strong and the degree to which MDMs have been absorbed into clinical practice varies widely across conditions and settings. We conducted a large mixed-methods study of multidisciplinary teams in chronic diseases to examine and explore determinants of effective decision making. We applied a transparent and explicit consensus development method to develop recommendations, based on our results, to improve MDM decision making and effectiveness.

Methods

We collected qualitative and quantitative data from 12 multidisciplinary teams (gynaecological, skin and haematological cancers, mental health, memory clinics and heart failure). Data included non-participant observation of 370 MDMs and follow up of medical records, 53 interviews with healthcare professionals and 20 patient interviews. We triangulated these datasets to increase the internal validity and consistency of our findings. Over the course of successive analytic meetings we identified patterns of convergence to develop a coherent framework for understanding our findings. Based on this analysis we derived a series of potential recommendations for discussion and rating by an expert consensus development panel including policy makers, healthcare professionals and patient representatives.

Results

Issues for discussion by the consensus panel included: whether or not patients should attend MDMs; how patient perspectives can be best represented; determining which patients, and indeed whether all patients should be included for discussion; suggestions for improvements in MDM processes, including the structure and co-ordination of MDMs; whether functions such as teaching and emotional support for team members have a valid role in the MDM, and if so, how best to incorporate them. The issue of how to incorporate multi-morbidity in disease specific MDMs was also considered.

Conclusion

We have conducted the largest study of its kind in this area and the first to examine and compare MDMs for different chronic diseases. In addition, the use of a diverse range of qualitative and quantitative data allowed an unprecedented breadth and depth of data to be explored. This produced wide ranging, important and feasible recommendations to improve the effectiveness of MDMs which, the data suggest are generalisable to different patient groups.
PP50 Body Mass Index, Waist Circumference and Incident Coronary Heart Disease in the Million Women Study
Authors: Canoy D , Cairns B J , Balkwill A , Wright F L , Reeves G , Green J , Beral V
Published: September 2013

Background

Body mass index (BMI) and waist circumference are measures of total and abdominal adiposity, respectively, and both relate to coronary heart disease (CHD) risk. However, these measures are highly correlated, and require large-scale studies to reliably examine their separate associations with incident CHD. We examined the prospective relation of BMI and waist circumference with incident CHD in a large UK population-based cohort.

Methods

0.5 million women (mean age = 60 years) without vascular disease or cancer completed a health and lifestyle questionnaire (1999 to 2005), and were followed prospectively for 5 years on average. Adjusted relative risks and cumulative incidence (first coronary hospitalisation or death) from age 55 to 74 years were calculated using Cox regression. Plasma apolipoproteins were assayed in 6,295 randomly selected participants.

Results

Over 10,000 women had a first coronary event during follow-up. The risk for incident CHD increased with both increasing BMI and waist circumference. When BMI and waist circumference were cross-classified by one another, the risk for incident CHD increased with increasing BMI within each waist circumference category (< 70, 70–79.9, ≥ 79 cm) (P for trend < 0.05); similarly, the risk increased with increasing waist circumference within each BMI category (<25, 25–29.9, ≥30 kg/m2) (P for trend < 0.05). The cumulative CHD incidence was lowest in women with BMI < 25 kg/m2and waist circumference < 70 cm, with 7% developing CHD between ages 55 and 74 years, and highest in women with BMI ≥ 30 kg/m2and waist circumference ≥ 80 cm, with 12% developing CHD. Similar associations were observed for apolipo protein B to A1 ratio which increased with increasing BMI and waist circumference particularly in non-obese women (P for trend <0.05).

Conclusion

In this large cohort of UK women, BMI and waist circumference are separately and independently associated with incident coronary disease. An atherogenic pattern of apolipoprotein profile may partly mediate these associations.
PP51 Association between Overweight/Obesity and Health Care Utilisation Among Older Adults: Results from the Irish Longitudinal Study of Ageing
Authors: McHugh S , Normand C , Browne J , Kearney P
Published: September 2013

Background

Given the ageing population and rising prevalence of obesity, the aim was to examine the association between body mass index (BMI) and health care utilisation in older Irish adults.

Methods

Baseline cross-sectional data from the Irish Longitudinal Study of Ageing (TILDA) were analysed. A clustered sample of addresses was chosen from all residential addresses in the Republic of Ireland. All household residents aged 50 or over and their spouses/partners were eligible to participate. A response rate of 62% was achieved, based on the proportion of selected households including an eligible participant who was successfully interviewed (total n = 6282 households). BMI was measured objectively using standard methods. WHO classifications were used to categorise BMI as normal (BMI 18.5 – 24.99 kg/m2), overweight (BMI 25 – 29.99 kg/m2) or obese (> 30 kg/m2). Those classified as underweight (n = 32) were excluded from analysis which was conducted using Stata v12.

Results

Preliminary analysis was based on the 5873 individuals aged 50 and over, who participated in the health assessment. Applying sample weights, 49% of the population are male (n = 2701) with a mean age of 63.1 years. The mean age of females was 64.1 years. Most participants were overweight (43%) or obese (35.7%). Unadjusted comparisons between normal, overweight and obese groups suggest a significant association with high GP use (≥4 visits) and the use of out-patient hospital services. Almost 50% of obese individuals had ≥4 visits to the GP in the previous 12 months, compared to 36% of normal and 39% of overweight individuals (p = 0.000). Similarly, 47% of obese individuals had visited hospital out-patient services compared to 41% of overweight and 39% of normal weight individuals (p = 0.003). There were also significant associations between BMI and hospitalisation (p = 0.02) and receiving a prostate exam (p = 0.04). There was no significant association between BMI category and use of emergency department (p = 0.1428) or attending mammography screening (p = 0.8959).

Discussion

Preliminary analysis suggests increased use of health services among older adults who are overweight or obese. Multivariate analysis will be conducted to examine whether overweight/obesity is an independent predictor of health service use in this population.
PP52 Obesity Prevention in Scotland: A Policy Analysis using the Angelo Framework
Authors: Mooney J D , Frank J , Jepson R , Geddes R
Published: September 2013

Background

The Scottish Government’s ‘Route-Map towards Healthy Weight’ published in 2010, aspired towards a comprehensive cross-government approach to tackling the rising prevalence of obesity, with commitments to addressing the fundamental societal drivers of the epidemic. The subsequent ‘Route-Map Action Plan’ set out 62 policies targeted at nutrition, physical activity or both, at all stages of the life course. We categorised each policy using the ANGELO Framework (Analysis Grid for Environments Linked to Obesity), to assess the appropriateness and likely impact of the balance of measures being proposed. ANGELO uses four broad ‘domains’: Physical, Economic, Legislative and Socio-cultural, as well as two ‘scales’ of intervention: ‘Macro’ for the national, regional or sectorial level and ‘Micro’ for the local neighbourhood/community/institutional level.

Methods

Two assessors (JM & RJ), used the guidance outlined by the originators of ANGELO to independently allocate a category for each intervention according to its domain (Physical, Economic, Legislative or Socio-cultural), scale (Macro or micro); and predominant ‘focus’ (activity versus nutrition). A third assessor (RG) then examined those policies where there were differences in allocation and a consensus on each was agreed by discussion. The resulting distribution of policies by scale and domain was compared with the current consensus of international research evidence around which combinations of measures are likely to have the greatest impact at a population level.

Results

Across the four environmental domains, the distribution of the 62 separate policy initiatives was skewed towards behavioural (Socio-cultural) measures (37.1%) and the Physical environment (33.1%) (i.e. surroundings), with less emphasis on Legislative measures (21.8%) or Economic interventions (6.4%). The distribution of both intervention scale and focus was more evenly spread with just over half of all policies (51.8%) targeted at the Macro-level scale and just under half (46.7%) having a nutrition focus.

Conclusion

Policy interventions (planned or underway), to tackle obesity which are supported by the Scottish Government, span across all four domains of the obesogenic environment as described by the ANGELO framework. The predominance of Socio-cultural/(i.e. behavioural) orientated interventions over Legislative and particularly Economic (or fiscal) measures (such as a sugared beverage tax), is common for most Governments, although the balance of evidence suggests that targeting the latter domains would be more effective. There is a need therefore to strive for a more balanced approach across all spheres of Government influence, with economic interventions representing the area where actions should particularly be increased.
PP55 Socioeconomic Status and Chronic Kidney Disease: Further Findings from the Health Surveys for England 2009 and 2010
Authors: Fraser S D S , Roderick P J , Aitken G R , Roth M A , Mindell J S , Moon G , Matthews B , O’Donoghue D J
Published: September 2013

Background

Renal replacement therapy rates are higher in more deprived populations in developed countries. The relationship between population-level prevalence of chronic kidney disease (CKD) and socio-economic status (SES) is less clear. Albuminuria is also recognised as an independent risk factor for poor CKD outcomes but again little is known about its relationship with SES. The nationally representative Health Surveys for England (HSE) 2009 and 2010 showed mixed evidence for variation of CKD prevalence by area deprivation defined by ‘Spearhead Primary Care Trust’ status. The present study aimed to examine the relationship between CKD and SES in more detail, and to include investigation of associations of albuminuria.

Methods

Data from the 2009 and 2010 HSEs were combined, giving a total of 5,799 individuals with kidney function data. Prevalence of moderate to severe CKD (stage 3–5), using the Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) estimating equation, and albuminuria were calculated. Multivariate logistic regression models were used to determine the associations of SES measures with CKD and albuminuria, adjusted for demographic, lifestyle and clinical factors.

Results

Prevalence of CKD Stage 3–5 was 5.2%, and any albuminuria 8.0%. After accounting for age-sex interaction, age-sex adjusted CKD 3–5 prevalence was associated with lack of qualifications (OR 2.27 [95% CI 1.40, 3.69]), low income (1.50 [1.02, 2.21]) and household tenure (1.36 [1.01, 1.84]) for rented vs. ownership). Only tenure remained significant after further adjustment for lifestyle and clinical factors (smoking, body mass index, hypertension, diabetes and ethnicity). Age-sex adjusted albuminuria prevalence was associated with low income (1.79 [1.35, 2.36]) most deprived quintile of index of multiple deprivation (1.72 [1.24, 2.41]), vehicle ownership (1.59 [1.25, 2.02]) and tenure (1.46 [1.18, 1.81]); these associations persisted after full adjustment.

Conclusion

There was little evidence of socioeconomic variation in CKD 3-5 prevalence in these HSE participants. By contrast, albuminuria prevalence varied by several measures of SES. This suggests a higher risk of CKD progression in lower SES groups. When combined with the higher prevalence of Type 2 diabetes in lower socioeconomic groups, this may contribute to the inverse gradient of renal replacement therapy rates by SES. This has implications for the early detection of CKD and albuminuria, and for equity of care in managing CKD.
PP67 Psychological Health and Physical Activity from Adolescence To Mid-Adulthood: Evidence of Bi-Directional Associations in the 1958 British Birth Cohort
Authors: Pereira S M Pinto , Geoffroy M C , Power C
Published: September 2013

Background

Physical activity (PA) is cross-sectionally associated with lower prevalence of depression and other indicators of psychological well-being. Few longitudinal studies examine the possibility of bi-directional associations between activity and psychological health.

Using data from the 1958 British Birth cohort (maximum N = 14,072) over four decades of life we examined (i) cross-sectional associations to establish whether psychological ill-health is concurrent with lack of PA at several life-stages, and (ii) longitudinal associations to elucidate the direction of association, i.e. (1) psychological health and prior PA, and (2) PA and prior psychological health.

Methods

Psychological health was assessed using validated, age appropriate instruments from questionnaires to teachers (11y, 16y) and participants (23y, 33y, 42y, 50y). Measures were converted to (i) standard deviation (SD) scores and (ii) categorised to represent “severe distress” (top 10% at each age). PA reported by mothers (11y) and participants (16y, 23y, 33y, 42y, 50y), was classified at all ages into four categories. Covariates from different life-stages included: body mass index, socioeconomic position, education and physical limiting illness.

Results

Using linear regressions, we found that individuals with poorer psychological health were less physically active, but patterns of association varied by age. In adolescence, there was a dose-response relationship: e.g. at 16y, per category higher activity, psychological health was lower by 0.08 (0.07, 0.10) SDs. In adulthood, there was a threshold effect: e.g. at 50y, those active 1+/wk had a 0.20 (0.15, 0.24) lower SD score than those active <1/wk. Associations persisted after adjustment, although attenuated. We assessed directionality using random effects models to (1) psychological health (16-50y) with time-varying PA as an explanatory variable, and (2) PA (16-50y) with time-varying psychological health as an explanatory variable. Preliminary analysis suggests that relationships are bi-directional. The odds ratio of severe distress was 0.81 (95% CI 0.75, 0.89) for those physically active at the previous sweep compared to the inactive. However, there was a suggestion that the relationship weakened with age. Prior psychological health predicted PA similarly across ages. Between 16-50y, the odds of being physically active if severely distressed previously was 0.67 (0.62, 0.73). Results were unchanged after adjustment.

Conclusion

PA and psychological ill-health are concurrent over decades of life. The relationship appears to be bi-directional, although weakening with age for PA to subsequent psychological ill-health. Findings suggest that PA throughout adolescence and young adulthood may alleviate subsequent psychological ill-health.
PP70 Knowledge Brokers or Policy Entrepreneurs? Strategies to Influence the Policy Process
Authors: Oliver K , Money A , Vocht F de
Published: September 2013

Background

Understanding the impact and process of evidence-use in policy has been a major focus for researchers in recent years. Researchers often focus on (a) how to increase uptake of research, (b) validating models of knowledge transfer and (c) advocating for the use of knowledge brokers. Several ‘job descriptions’ for knowledge brokers have been published. However, the influence and impact of knowledge brokers is unclear. Policy actors who are known to be influential can also be characterised in terms of daily activities. This study aims to describe the activities of powerful and influential actors and compare them with knowledge brokerage frameworks from the literature.

Methods

A policy community in a large UK conurbation was defined as ‘involved in delivering, developing or implementing public health policy’, and included regional and national actors. Policy actors’ accounts of the policy process (including evidence use, policy processes and policy networks) were gathered through 23 semi-structured interviews and over 18 hours of observations of NHS and local authority meetings, both public and private. Data were analysed using framework analysis.

Results

Knowledge brokerage roles were identified as part of the policy process, but were played by policy makers already in the policy community, rather than researchers and academics. Knowledge brokerage frameworks describe the involvement of policy makers in the research process, but descriptions of other activities involved in the policy process showed that knowledge brokerage strategies formed a small part of a much wider spectrum of policy-influencing strategies; controlling policy organisations, controlling policy content, controlling decision-makers and using relationships. These activities take place over long time periods, and over a range of policy areas, questioning the utility of constructions such as “public health policy” for analysing evidence-use and policy processes.

Discussion

Knowledge brokerage is often presented as an intervention to increase research uptake, to be carried out by researchers. We show that the activities described are carried out by actors within the policy environment, questioning the usefulness of such approaches. Knowledge brokerage forms a small part of a spectrum of policy-influencing strategies employed by policy actors, who operate over a longer time-span and a wider range of policies than previously acknowledged. Providing empirical descriptions of the activities of policy actors provides insight into both how to influence policy, and a framework to understand the policy process itself.
PP71 Cultures of Evidence Among Decision-Makers in Non-Health Fields: Systematic Review of Qualitative Evidence
Authors: Lorenc T , Tyner E , Petticrew M , Martineau F , Phillips G , Lock K
Published: September 2013

Background

Many non-health public policy sectors which form part of local government may have impacts on population health outcomes. Decision-makers’ views about research evidence, and their practices of evidence use, are less well understood in these sectors than in healthcare or public health.

Methods

Systematic review (PRISMA) of qualitative evidence. A range of sources were searched. Studies were included if: they included local policy-makers or practitioners in transport, housing, urban planning and regeneration, crime and policing, or licensing; and reported substantive data on views, beliefs or experiences regarding research evidence. Study findings were synthesised using a grounded-theory thematic analysis approach.

Results

A range of contextual factors impact on evidence use, including personal contacts, institutional structures and power relationships, and national legal or policy constraints. Academic research evidence is often a relatively small part of the overall knowledge base for decision-making. The types of evidence used vary considerably across sectors: evaluations of effectiveness are generally a secondary concern, with descriptive evidence on contexts being more highly valued. General messages about the value of evidence-based policy and practice have been widely disseminated, and some sectors report relatively high rates of evidence use. However, decision-makers’ understandings of these messages are highly divergent, and the ways evidence is used in practice often do not conform to academic researchers’ preconceptions.

Discussion

Compared to healthcare or public health, cultures of evidence in non-health sectors present distinct issues. The findings of this review indicate the need for a broader perspective on evidence use, which takes into account the whole decision-making process, and the interaction of academic research with more informal and situated forms of knowledge. Linear models of ‘knowledge translation’ may not capture the complexity of potential relations between knowledge and practice, and the wide variation in decision-makers’ understandings of the concept of evidence.