bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Numerical Analysis in the Transient Solution of Two-Dimensional Heat-Transfer Problem With Natural and Forced Convection
Authors: Hellman S. K. , Habetler George , Babrov Harold
Published: February 2022

In order to determine thermal stresses in a nuclear reactor during power build-up and decay, it is necessary to derive a method of evaluating the transient temperatures involved. This paper presents an analysis of a two-dimensional metallic structure containing many flow channels. Cooling is accomplished through natural and forced convection. Heat generation and conduction are considered as functions of time and two space variables; while the laminar motion of the liquid metal is expressed by means of transient one-dimensional flow-rate equations, derived from Euler’s equation. The system is set up as a thermal network so that the resulting finite difference equations can be solved by a digital computer.
Heat Transfer From a Rotating Plate
Authors: Young R. L.
Published: February 2022

Experimental values and comparisons with previously proposed analytical solutions are presented for the surface coefficient of heat transfer by convection from a rotating body. The particular case investigated was that of an upward-facing heated circular plate rotated in ambient air about a vertical axis normal to its surface. It was observed that for Reynolds numbers less than 500,000 both natural and forced-convection phenomena were of importance, while at Reynolds numbers greater than 500,000 forced convection alone was of prime significance. Curves and equations are presented which permit the calculation of heat transfer by convection from such a surface.
The Thermal Conductivity of Organic Liquids
Authors: Pagerey P. F. , St. Clair C. R. , Sibbitt W. L.
Published: February 2022

A primary instrument was constructed for the measurement of the thermal conductivity of liquids at atmospheric pressure. An aluminum instrument was constructed such that it used a liquid layer only 0.022 in. thick in order to eliminate the effects of convection. Measurements were made over the approximate temperature range from 20 to 90 C with the following compounds:

1 Ethyl acetate

2 Vinyl acetate

3 Butyl acetate

4 Adiponitrile

5 Acrylonitrile (commercial)

6 Distilled acrylonitrile

7 Dibutyl phthalate

8 Methyl methacrylate

9 Dimethyl formamide

10 Dimethyl acetamide

The experimental accuracy was estimated to be approximately ±2.5 per cent.
The Determination of Thermal Diffusivity of Aluminum Alloys at Various Temperatures by Means of a Moving Heat Source
Authors: Rosenthal Daniel , Friedmann N. E.
Published: February 2022

Previous work has demonstrated that the theory of moving heat sources can be used for a direct and rapid determination of thermal diffusivity in metals at high temperatures. Present work describes the experimental procedure and instrumentation which have been developed for metals of relatively high thermal diffusivity, 0.2 cm2/sec and more. The method was applied to two aluminum alloys, 3S and 61S which are commonly used for welding purposes. Therefore the results are believed to have practical significance. The thermal diffusivity of both alloys shows little or no increase with temperature from 150 to 1000 F. To check the reliability of results the thermal diffusivity of a sample of deoxidized copper was determined, first by this method, and then independently from its electrical resistivity using published data of the Franz-Wiedemann ratio for copper alloys. The two determinations agreed within ±1 per cent. The results on aluminum alloys proved that values of thermal diffusivity, averaged over an interval of 100 deg F, can be determined easily to three significant figures. The reproducibility of individual results was found to be largely independent of the velocity and intensity of the heat source and the wall thickness of the specimens. It was of the order of ±2 per cent. However, six consecutive runs can be made readily within two or three hours, thus reducing the probable error to a much lower value.
Temperature Charts for Internal Heat Generation
Authors: Heisler M. P.
Published: February 2022

A number of graphs are presented for determining transient heating effects in simple bodies having uniform internal heat sources. The range of parameters covers Fourier’s modulus between 0 and ∞, and relative boundary resistance—also referred to as the inverse Biot or modified Nusselt number—between 0 and ∞. The full range of position variable is covered except for the case of Fourier’s modulus less than 0.2. In this case the complete range is covered only for values of relative boundary resistance equal to zero.
Feedwater Heaters—A User’s Viewpoint
Authors: Arnow S. M.
Published: February 2022

Correct heating surface and the proper terminal approach are necessary requirements for efficient plant performance. However, the most important factors from the user’s standpoint are those which make for continuous trouble-free operation. These include such requirements as suitable material protection against direct impingement on tubes by steam and flashing drains, provision for avoiding corrosive-gas accumulation, proper location of vents, more attention to the mechanical details, and careful study of all failures in order to determine the causes and to provide the cures. Several heater-cycle arrangements are shown and some typical troubles and remedies are discussed.
The Sintering Test, an Index to Ash-Fouling Tendency
Authors: Barnhart D. H. , Williams P. C.
Published: February 2022

This paper describes a laboratory test for determining the tendency of an ash to form hard, bonded deposits in the convection-tube banks of coal-fired boilers. The sintering test, as it is called, has been applied to several phases of the over-all problem of ash deposition including (a) the evaluation of factors in boiler operation, (b) the classification of coal according to its ash-fouling characteristics, and (c) the selection and testing of additives for inhibiting or preventing ash fouling. The results of these studies are presented herein.
Correlation of Fir-Tree-Type Turbine-Blade-Fastening Strength With Mechanical Properties of Materials
Authors: Holms A. G. , Repko A. J.
Published: February 2022

Some materials under consideration for aircraft gasturbine disks are notch-sensitive at certain operating times, temperatures, and stress levels. Prediction of engine life requires knowledge of the type of mechanical-property test that will correlate with engine life and requires knowledge of the quantitative relationship. Elevated-temperature time-dependent spin tests were run on model disks with fir-tree blade fastenings. Material and test conditions were selected to cover a wide range of notch sensitivity. Results showed that life for tensile mode failures could be predicted from notched rupture tests.
Application of Internal Liquid Cooling to Gas-Turbine Rotors
Authors: Alpert Sumner , Grey R. E. , Drake D. D.
Published: February 2022

Application of internal liquid cooling to the rotor and blades of a gas turbine allows the inlet-gas temperature to be increased and alloys low in strategic materials to be used. A small gas turbine was designed for a gas temperature of 1750 F with lean-alloy rotor materials. The design featured closed-system cooling with interchangeable blades. Cold-air tests, hot tests, and endurance tests totaling 100 hr, have been run on a single-stage test turbine. Aerodynamic and thermodynamic data correlated well with expected values and the mechanical performance was satisfactory.
Solution of Transient Heat-Transfer Problems by the Resistance-Network Analog Method
Authors: Liebmann G.
Published: February 2022

The resistance-network analog method for the solution of transient heat-conduction problems, described in an earlier paper, is extended to problems involving heat transfer across a surface, or generation or absorption of heat in the interior of the system. The flexibility of the method and its “stability” are retained in this extension. The method also can be applied to latent-heat problems. Several examples are discussed which illustrate the technique.
Design Basis for Multiloop Positional Servomechanisms
Authors: Lees Sidney
Published: February 2022

A design basis for multiloop positional servomechanisms is developed by co-ordinating the specifications, dynamic characteristics, interferences, and uncertainties. The design basis arises from a consideration of the generation of torques by the system. The limitations of the system performance are distinguished from component characteristics. When the concept of frequency-dependent coefficients is employed, it is shown that the performance may be comprehended from knowledge of second-order systems. Seven models are examined. Estimates of useful values of the parameters for each model are confirmed by analog studies.
Control-Valve Plug Design
Authors: Wiedmann J. A. , Rowan W. J.
Published: February 2022

With the aid of a few basic flow relationships and a series of empirical coefficients, it is possible to design a control-valve plug which will have a predetermined flow characteristic. It has been found that the friction losses in the valve body cannot be neglected in such a design, and that the efficiency of the valve-port opening also must be included. In this paper a contoured plug has been designed with an equal percentage characteristic for a 2-in. top and and bottom-guided, single-seated, globe-type valve. The paper also includes the results of a flow test on a plug made according to this design plus a discussion of the principal limitations associated with this general approach.
An Investigation of Cemented Tungsten Carbide as Bearing Material: Progress Report No. 2
Authors: Kozacka J. S. , Erickson H. A. , Highriter H. W. , Gabriel A. F.
Published: February 2022

This paper is a continuation of Report No. 1 which was contributed by the Machine Design and Production Engineering Divisions and presented at the 1952 Annual Meeting. The investigation is principally concerned with the effects of higher bearing pressures than previously used on bearing performance, the effect of bearing roughness surface on coefficient of friction, and the effects of speed on coefficient of friction under otherwise constant conditions. In these tests the same bearings were used as for tests reported previously. These bearings and journals were made of straight tungsten carbide with 6 per cent cobalt as the binder.
The Friction Process in Metal Cutting
Authors: Finnie Iain , Shaw M. C.
Published: February 2022

Coefficients of friction obtained in metal cutting are often greatly different from those obtained with the same metal pair in conventional sliding-friction experiments. If only the rake angle is changed during cutting, a wide range of friction coefficients is obtained, and it is noted that the tendency toward complete adhesion of chip to tool increases as coefficient of friction decreases. These two apparent anomalies are explained by considering the fundamental mechanism of friction and the conditions which exist in cutting. It is shown that a coefficient of friction is inadequate to characterize the friction process in cutting, being mainly an indication of the normal stress on the tool face, and thus strongly dependent on the shear process in cutting.
Critical Considerations on Cavitation Limits of Centrifugal and Axial-Flow Pumps
Authors: Wislicenus G. F.
Published: February 2022

This is the presentation of a problem, not of its solution. A critical examination of the cavitation problem of centrifugal and axial-flow pumps indicates that such pumps are operated at higher speeds than reasonably can be expected to exclude cavitation or local pressures below the vapor pressure of the fluid pumped. This fact is revealed by relating the over-all cavitation characteristics of pumps for which empirically determined values are available to detail characteristics usually described as blade-pressure coefficients which are sufficiently backed by empirical and theoretical information to permit rational interpretation and an estimate of future developments, including pump operation with fully developed cavitation.
The Supercharged-and-Intercooled Free-Piston-and-Turbine Compound Engine—A Cycle Analysis
Authors: London A. L.
Published: February 2022

This paper supplements a previous study. Its purpose is to clarify the position occupied by the supercharged-and-intercooled cycle variant of the free-piston-and-turbine compound engine relative to the simple cycle. Two points of view are employed in these considerations—one relating to question of whether or not to supercharge an existing simple-cycle prototype; and the second relating to the basic decision of whether to develop a supercharged-and-intercooled cycle, or alternatively to develop the simple cycle for the same degree of pressure charging of the engine cylinder. From the first viewpoint, as an example, it appears to be attractive to supercharge a 6:1 pressure-ratio simple cycle up to 8:1 by a blower of 1.33 pressure ratio. The gain is roughly 50 per cent in power output and this must be weighed against the additional complexity, bulk, weight, and cost associated with the supercharger and its turbine drive, together with the intercooler and its ducting. Moreover, the cylinder combustion rate is increased in proportion to the power gain so that cylinder and piston heat problems are more severe. From the second viewpoint, the supercharged-and-intercooled cycle possesses no significant advantages and many disadvantages.
The Thermodynamics of Cooled Turbines: Part 1—The Turbine Stage
Authors: Hawthorne W. R.
Published: February 2022

A procedure has been obtained for calculating the effect of cooling on turbine-stage efficiency by visualizing the flow in the blade passages as one-dimensional compressible flow in a conical tube with heat transfer and friction. The use of Reynolds’ analogy between friction and heat transfer permits the results to be correlated in terms of the blade-profile loss coefficient in low-speed flow, the change of passage area in the blade section and the ratio of average blade-surface temperature to the stagnation temperature of the gas relative to the blades. Simple expressions are obtained for the amount of heat abstracted in a cooled row of blades and the drop in turbine-stage efficiency resulting from cooling. Calculations for some typical stages show that, with blades cooled appreciably below the gas temperature, the amount of heat removed may be as much as 5 per cent of the calorific value of the fuel per row of cooled blades and the decrease in turbine-stage efficiency as much as 3 per cent when both nozzles and blades are cooled appreciably. The use of impulse and low reaction stages reduces to a small fraction of a per cent the effect on the stage efficiency of cooling the rotor blades only.
Free-Convection Heat Transfer From a Horizontal Right Circular Cylinder to Freon 12 Near the Critical State
Authors: Doughty D. L. , Drake R. M.
Published: February 2022

Free-convection heat-transfer coefficients have been measured on a horizontal circular cylinder to Freon 12 near the critical-state conditions as a function of the temperature difference between the test cylinder and the Freon environment. Experimental heat-transfer coefficients have been determined for constant Freon temperatures of 233, 244, and 259 F, and for a constant pressure of 580 psia, the critical pressure of Freon 12. In all cases the heat-transfer coefficients have been determined as functions of the temperature difference between the test cylinder and the Freon for densities varying from supercritical to subcritical. In the region near the critical state the experimental heat-transfer coefficients are shown to increase tenfold over the typical values in the superheated-vapor region. Satisfactory correlation of the present results with the work of other investigators in the field of free-convection heat transfer has been made for state conditions removed from the critical.
Redes informales de crianza en el ámbito adoptivo
Authors: Grau Rebollo Jorge
Published: February 2022

El fenómeno de las adopciones internacionales ha sido profusamente estudiado en los últimos 15 años desde diversas disciplinas, incluida la antropología social y cultural, si bien algunos ámbitos —como el del papel de las redes personales de apoyo en la crianza adoptiva— no han recabado todavía una atención suficiente en nuestra disciplina. Para contribuir a cubrir esta carencia, abordaré en este artículo las principales conclusiones de una investigación orientada a analizar los cuidados y roles entendidos como parentales y a explorar la extensión de dichos roles en las redes de crianza configuradas en torno a menores adoptados por vía internacional en procesos no considerados de riesgo por razones de salud física o mental, ni debido a otros indicadores socioculturales de vulnerabilidad. Con este fin, me centraré principalmente en el examen de la trama personal de soporte informal de 50 padres y madres en lo que refiere a los sectores clave que, en su quehacer cotidiano, han considerado más importantes para la crianza de sus hijos e hijas adoptados. Con ello, trataré de identificar los tipos principales de apoyo requerido, así como a los principales agentes implicados en tareas de cuidado (independientemente de su edad, profesión, vínculo social o proximidad genealógica con las familias adoptivas), las razones de su relevancia y las características esenciales de las redes resultantes.
Paradojas de género: Mujeres que declinan la maternidad y padres que reclaman la crianza
Authors: Fernández-Rasines Paloma , Bogino Larrambebere Mercedes
Published: February 2022

En este artículo queremos poner de manifiesto una situación paradójica para los patrones normativos de sexo/género con relación a la crianza. La discusión plantea en qué medida la fuga de mujeres del mandato cultural de la maternidad y la concurrencia de los hombres en los procesos de crianza suscitan la emergencia de modelos que nos hablan de figuras parentales que transitan con mayor libertad y autonomía, más allá de los límites impuestos por los roles de género. En primer lugar, una revisión de la literatura especializada nos ha provisto de los desarrollos conceptuales en torno a la posición social de las mujeres sin maternidad, así como de la construcción de la paternidad por parte de hombres que asumen y reivindican la crianza cotidiana de hijos e hijas. En segundo lugar, se muestran los resultados del trabajo de campo etnográfico realizado a través de entrevistas biográficas a mujeres y hombres que se posicionan como sujetos de la maternidad declinada y la paternidad asumida, respectivamente.
Development of a Remote, Course-Based Undergraduate Experience to Facilitate
In Silico
Study of Microbial Metabolic Pathways
Authors: Parks Samantha T. , Taylor Caroline
Published: February 2022

Course-based undergraduate research experiences often occur in a physical lab space, but they can also be offered remotely while maintaining course expectations and providing opportunity for authentic student engagement in research. Using a novel framework, remote-learning Microbial Ecology lab students used microbes isolated via antimicrobial-challenged Winogradsky columns to investigate phylogeny and metabolism through a hypothesis-driven meta-analysis (MA). Students used 16S rRNA and key metabolic enzyme to compare phylogeny; enzymes were modeled and evaluated for putative conserved domains, culminating in primer design and analysis.
Childhood versus early-teenage onset Leber’s hereditary optic neuropathy: visual prognosis and capacity for recovery
Authors: Siedlecki Jakob , Koenig Susanna , Catarino Claudia , Schaumberger Markus M , Schworm Benedikt , Priglinger Siegfried Georg , Rudolph Guenther , von Livonius Bettina , Klopstock Thomas , Priglinger Claudia S
Published: February 2022

Objective

In Leber’s hereditary optic neuropathy (LHON) in children and teenagers, the influence of age on visual prognosis has not yet been investigated.

Methods

Patients from the mitoNET registry with LHON onset at age 4–16 years with at least 4 years of follow-up without treatment were included. Visual acuity (VA) at baseline, lowest VA ever recorded (nadir) and VA at end of follow-up were compared between childhood onset (ChO, ≤12 years of age) and early-teenage onset (eTO; 13–16 years).

Results

Out of 231 patients with LHON, 19 met the inclusion criteria (8.2%). There were 11 patients in the ChO and 8 patients in the eTO group. Mean age at onset was 8.6 (SD 2.1) years (ChO) and 15.4 (SD 0.7) years (eTO) (p<0.00001). Follow-up was mean 184 (SD 129) months (ChO) and 119 (SD 78) months (eTO) (p=0.22). Baseline VA was similar between both groups in better (p=0.96) and worse eyes (p=0.54). In worse eyes, both groups deteriorated similarly (p=0.79) until nadir and showed similar recovery until end of follow-up (p=0.38). In better eyes, both groups deteriorated similarly (p=0.16) until nadir. From nadir until end of follow-up, better eyes in the ChO group showed a significantly better recovery (−0.35 (SD 0.36) vs −0.01 (SD 0.06) logMAR; p=0.02) than eTO eyes.

Conclusion

Visual prognosis of LHON in children is much more favourable in cases of childhood onset (≤12 years of age) as compared with teenage onset (13–16 years), mostly due to better recovery from nadir in childhood onset.
Burnout, coping strategies and help-seeking in general practitioners: a two-wave survey study in Denmark
Authors: Pedersen Anette Fischer , Vedsted Peter
Published: February 2022

Objective

Work pressure remains an issue among general practitioners (GPs). Nevertheless, GPs rarely seek help for symptoms of burnout. The aim of this study was to examine whether burnout level was associated with coping strategies and help-seeking behaviour during time pressure.

Design

A two-wave nationwide survey (2016 and 2019) based on questionnaire data from 1059 GPs.

Setting

Primary care in Denmark.

Methods

Burnout was measured by the Maslach Burnout Inventory (MBI), whereas coping strategies and help-seeking behaviour were measured by questions developed for the study. A composite score of quartile points was calculated for the three subscales of the MBI subscales. A score ≥9 was categorised as high level of burnout, and the composite score of 2019 was used as outcome. Data were analysed with logistic regression adjusted for sex, age and composite burnout score in 2016.

Results

High scores in 2016 on four key factors were associated with increased risk of high composite burnout score in 2019. These factors were compromising work (ORadjusted=2.27, 95% CI=1.45 to 3.56), postponing decisions (ORadjusted=1.53, 95% CI=1.04 to 2.24), delaying tasks (ORadjusted=1.61, 95% CI=1.16 to 2.25) and reducing breaks (ORadjusted=1.46, 95% CI=1.01 to 2.11) during time pressure. A lower risk of high composite burnout score was seen in 2019 in GPs who had sought help compared with GPs who did not seek help despite a perceived need (ORadjusted=0.59, 95% CI=0.35 to 0.97).

Conclusion

Certain coping strategies used in 2016 were associated with increased risk of high burnout score in 2019, whereas lower risk of high burnout was seen in the GPs seeking help. These findings are relevant to reduce burnout rates among GPs.
Strategies prescribers and pharmacists use to identify and mitigate adverse drug reactions in inpatient and outpatient care: a cognitive task analysis at a US Veterans Affairs Medical Center
Authors: Nguyen Khoa Anh , Militello Laura G , Ifeachor Amanda , Arthur Karen J , Glassman Peter A , Zillich Alan J , Weiner Michael , Russ-Jara Alissa L
Published: February 2022

Objective

To develop a descriptive model of the cognitive processes used to identify and resolve adverse drug reactions (ADRs) from the perspective of healthcare providers in order to inform future informatics efforts

Setting

Inpatient and outpatient care at a tertiary care US Veterans Affairs Medical Center.

Participants

Physicians, nurse practitioners and pharmacists who report ADRs.

Outcomes

Descriptive model and emerging themes from interviews.

Results

We conducted critical decision method interviews with 10 physicians and 10 pharmacists. No nurse practitioners submitted ADR incidents. We generated a descriptive model of an ADR decision-making process and analysed emerging themes, categorised into four stages: detection of potential ADR, investigation of the problem’s cause, risk/benefit consideration, and plan, action and follow-up. Healthcare professionals (HCPs) relied on several confirmatory or disconfirmatory cues to detect and investigate potential ADRs. Evaluating risks and benefits of related medications played an essential role in HCPs' pursuits of solutions

Conclusions

This study provides an illustrative model of how HCPs detect problems and make decisions regarding ADRs. The design of supporting technology for potential ADR problems should align with HCPs' real-world cognitive strategies, to assist fully in detecting and preventing ADRs for patients.
Premature mortality in early-intervention mental health services: a data linkage study protocol to examine mortality and morbidity outcomes in a cohort of help-seeking young people
Authors: McHugh Catherine , Song Yun Ju Christine , Zmicerevska Natalia , Crouse Jacob , Nichles Alissa , Wilson Chloe , Ho Nicholas , Iorfino Frank , Skinner Adam , Scott Elizabeth M , Hickie Ian B
Published: February 2022

Introduction

Understanding the risk of premature death from suicide, accident and injury and other physical health conditions in people seeking healthcare for mental disorders is essential for delivering targeted clinical interventions and secondary prevention strategies. It is not clear whether morbidity and mortality outcomes in hospital-based adult cohorts are applicable to young people presenting to early-intervention services.

Methods and analysis

The current data linkage project will establish the Brain and Mind Patient Research Register–Mortality and Morbidity (BPRR-M&M) database. The existing Brain and Mind Research Institute Patient Research Register (BPRR) is a cohort of 6743 young people who have accessed primary care-based early-intervention services; subsets of the BPRR contain rich longitudinal clinical, neurobiological, social and functional data. The BPRR will be linked with the routinely collected health data from emergency department (ED), hospital admission and mortality databases in New South Wales from January 2010 to November 2020. Mortality will be the primary outcome of interest, while hospital presentations will be a secondary outcome. The established BPRR-M&M database will be used to establish mortality rates and rates of ED presentations and hospital admissions. Survival analysis will determine how time to death or hospital presentation varies by identified social, demographic and clinical variables. Bayesian modelling will be used to identify predictors of these morbidity and mortality outcomes.

Ethics and dissemination

The study has been reviewed and approved by the human research ethics committee of the Sydney Local Health District (2019/ETH00469). All data will be non-identifiable, and research findings will be disseminated through peer-reviewed journals and scientific conference presentations.
Lactogenic hormones in relation to maternal metabolic health in pregnancy and postpartum: protocol for a systematic review
Authors: Rassie Kate Louise , Giri Rinky , Melder Angela , Joham Anju , Mousa Aya , Teede Helena J
Published: February 2022

Introduction

Maternal metabolic disease states (such as gestational and pregestational diabetes and maternal obesity) are reaching epidemic proportions worldwide and are associated with adverse maternal and fetal outcomes. Despite this, their aetiology remains incompletely understood. Lactogenic hormones, namely, human placental lactogen (hPL) and prolactin (PRL), play often overlooked roles in maternal metabolism and glucose homeostasis during pregnancy and (in the case of PRL) postpartum, and have clinical potential from a diagnostic and therapeutic perspective. This paper presents a protocol for a systematic review which will synthesise the available scientific evidence linking these two hormones to maternal and fetal metabolic conditions/outcomes.

Methods and analysis

MEDLINE (via OVID), CINAHL and Embase will be systematically searched for all original observational and interventional research articles, published prior to 8 July 2021, linking hPL and/or PRL levels (in pregnancy and/or up to 12 months postpartum) to key maternal metabolic conditions/outcomes (including pre-existing and gestational diabetes, markers of glucose/insulin metabolism, postpartum glucose status, weight change, obesity and polycystic ovary syndrome). Relevant fetal outcomes (birth weight and placental mass, macrosomia and growth restriction) will also be included. Two reviewers will assess articles for eligibility according to prespecified selection criteria, followed by full-text review, quality appraisal and data extraction. Where possible, meta-analysis will be performed; otherwise, a narrative synthesis of findings will be presented.

Ethics and dissemination

Formal ethical approval is not required as no primary data will be collected. The results will be published in a peer-reviewed journal and presented at conference meetings, and will be used to inform future research directions.

PROSPERO registration number

CRD42021262771.
Can patiromer allow for intensified renin–angiotensin–aldosterone system blockade with losartan and spironolactone leading to decreased albuminuria in patients with chronic kidney disease, albuminuria and hyperkalaemia? An open-label randomised controlled trial: MorphCKD
Authors: Mårup Frederik Husum , Peters Christian Daugaard , Christensen Jeppe Hagstrup , Birn Henrik
Published: February 2022

Introduction

Chronic kidney disease (CKD) is associated with significantly increased morbidity and mortality. No specific treatment of the underlying condition is available for the majority of patients, but ACE-inhibitors (ACE-I) and angiotensin II-receptor blockers (ARB) slows progression in albuminuric CKD. Adding a mineralocorticoid receptor-antagonist (MRA) like spironolactone has an additive effect. However, renin–angiotensin–aldosterone system (RAAS)-blockade increases the risk of hyperkalaemia which is exacerbated by the presence of CKD. Thus, hyperkalaemia may prevent optimal use of RAAS-blockade in some patients.

This project hypothesises that adding a potassium binder (patiromer) allows for improved RAAS-blockade including the use of MRA, thereby reducing albuminuria in patients with albuminuric CKD where full treatment is limited by hyperkalaemia.

If successful, the study may lead to improved treatment of this subgroup of patients with CKD. Furthermore, the study will examine the feasibility of potassium binders in patients with CKD.

Methods and analysis

An open-label, randomised controlled trial including 140 patients with estimated glomerular filtration rate (eGFR) 25–60 mL/min/1.73 m2, a urinary albumin/creatinine ratio (UACR) >500 mg/g (or 200 mg/g if diabetes mellitus) and a current or two previous plasma-potassium >4.5 mmol/L. Patients who develop hyperkaliaemia >5.5 mmol/L during a run-in phase, in which RAAS-blockade is intesified with the possible addition of spironolactone, are randomised to 12-month treatment with maximal tolerated ACE-I/ARB and spironolactone with or without patiromer.

The primary endpoint is the difference in UACR measured at randomisation and 12 months compared between the two groups. Secondary endpoints include CKD progression, episodes of hyperkalaemia, blood pressure, eGFR, markers of cardiovascular disease, diet and quality of life.

Ethics and dissemination

This study is approved by The Central Denmark Region Committees on Health Research Ethics (REFNO 1-10-72-110-20) and is registered in the EudraCT database (REFNO 2020-001595-15). Results will be presented in peer-reviewed journals, at meetings and at international conferences.
Concurrent changes in physical activity and body mass index among 66 852 public sector employees over a 16-year follow-up: multitrajectory analysis of a cohort study in Finland
Authors: Tiusanen Roosa , Saltychev Mikhail , Ervasti Jenni , Kivimäki Mika , Pentti Jaana , Stenholm Sari , Vahtera Jussi
Published: February 2022

Objectives

To identify concurrent developmental trajectories of physical activity and body mass index (BMI) over time.

Design

Prospective cohort study, repeated survey.

Setting

Cohort study in Finland.

Participants

66 852 public sector employees, who have been followed up for 16 years.

Outcome measures

Shapes of trajectories of changes in physical activity and BMI.

Results

At baseline, mean age was 44.7 (SD 9.4) years, BMI 25.1 (SD 4.1) kg/m2 and physical activity 27.7 (SD 24.8) MET hours/week. Four clusters of concurrent BMI and physical activity trajectories were identified: (1) normal weight (BMI <25 kg/m2) and high level of physical activity (30–35 MET hours/week), (2) overweight (BMI 25–30 kg/m2) and moderately high level of physical activity (25–30 MET hours/week), (3) obesity (BMI 30–35 kg/m2) and moderately low level of physical activity (20–25 MET hours/week) and (4) severe obesity (BMI >35 kg/m2) and low level of physical activity (<20 MET hours/week). In general, BMI increased and physical activity decreased during the follow-up. Decline in physical activity and increase in BMI were steeper among obese respondents with low level of physical activity.

Conclusions

Changes in BMI and physical activity might be interconnected. The results may be of interest for both clinicians and other stakeholders with respect to informing measures targeting increasing physical activity and controlling weight, especially among middle-aged people. Additionally, the information on the established trajectories may give individuals motivation to change their health behaviour.
Efficacy of probucol on cognitive function in Alzheimer’s disease: study protocol for a double-blind, placebo-controlled, randomised phase II trial (PIA study)
Authors: Lam Virginie , Clarnette Roger , Francis Roslyn , Bynevelt Michael , Watts Gerald , Flicker Leon , Orr Carolyn F , Loh Poh , Lautenschlager Nicola , Reid Christopher M , Foster Jonathan K , Dhaliwal Satvinder S , Robinson Suzanne , Corti Emily , Vaccarezza Mauro , Horgan Ben , Takechi Ryusuke , Mamo John
Published: February 2022

Introduction

Preclinical, clinical and epidemiological studies support the hypothesis that aberrant systemic metabolism of amyloid beta (Aβ) in the peripheral circulation is causally related to the development of Alzheimer’s disease (AD). Specifically, recent studies suggest that increased plasma concentrations of lipoprotein-Aβ compromise the brain microvasculature, resulting in extravasation and retention of the lipoprotein-Aβ moiety. The latter results in an inflammatory response and neurodegeneration ensues. Probucol, a historic cholesterol-lowering drug, has been shown in murine models to suppress lipoprotein-Aβ secretion, concomitant with maintaining blood–brain-barrier function, suppressing neurovascular inflammation and supporting cognitive function. This protocol details the probucol in Alzheimer’s study, a drug intervention trial investigating if probucol has potential to attenuate cognitive decline, delay brain atrophy and reduce cerebral amyloid burden in patients with mild-to-moderate AD.

Methods and analysis

The study is a phase II, randomised, placebo-controlled, double-blind single-site clinical trial held in Perth, Australia. The target sample is 314 participants with mild-to-moderate AD. Participants will be recruited and randomised (1:1) to a 104-week intervention consisting of placebo induction for 2 weeks followed by 102 weeks of probucol (Lorelco) or placebo. The primary outcome is changed in cognitive performance determined via the Alzheimer’s Disease Assessment Scales-Cognitive Subscale test between baseline and 104 weeks. Secondary outcomes measures will be the change in brain structure and function, cerebral amyloid load, quality of life, and the safety and tolerability of Lorelco, after a 104week intervention.

Ethics and dissemination

The study has been approved by the Bellberry Limited Human Research Ethics Committee (approval number: HREC2019-11-1063; Version 4, 6 October 2021). Informed consent will be obtained from participants prior to any study procedures being performed. The investigator group will disseminate study findings through peer-reviewed publications, key conferences and local stakeholder events.

Trial registration number

Australian New Zealand Clinical Trials Registry (ACTRN12621000726853).
Type 2 diabetes and risk of diverticular disease: a Danish cohort study
Authors: Wittström Felix , Skajaa Nils , Bonnesen Kasper , Pedersen Lars , Ekholm Ola , Strate Lisa , Erichsen Rune , Sørensen Henrik Toft
Published: February 2022

Objectives

To investigate the association between type 2 diabetes and risk of diverticular disease. Unlike previous studies, which have found conflicting results, we aimed to distinguish between diabetes types and adjust for modifiable risk factors.

Design

Observational cohort study.

Setting

Population-based Danish medical databases, covering the period 2005–2018.

Participants

Respondents of the 2010 or the 2013 Danish National Health Survey, of which there were 15 047 patients with type 2 diabetes and 210 606 patients without diabetes.

Primary and secondary outcome measures

Hazard ratios (HRs) for incident hospital diagnosis of diverticular disease adjusted for survey year, sex, age, body mass index (BMI), physical activity intensity, smoking behaviour, diet and education based on Cox regression analysis. As latency may affect the association between type 2 diabetes and diverticular disease, patients with type 2 diabetes were stratified into those with <2.5, 2.5–4.9 and ≥5 years duration of diabetes prior to cohort entry.

Results

For patients with and without diabetes the incidence rates of diverticular disease were 0.76 and 0.54 events per 1000 person years, corresponding to a crude HR of 1.08 (95% CI 1.00 to 1.16) and an adjusted HR of 0.88 (95% CI 0.80 to 0.96). The HR was lower among patients with ≥5 years duration of diabetes (adjusted HR: 0.76, 95% CI 0.67 to 0.87) than among those with 2.5–4.9 years or <2.5 years duration.

Conclusion

We found that patients with type 2 diabetes had a higher incidence rate of diverticular disease compared with patients without diabetes. However, after adjustment for modifiable risk factors, driven by BMI, type 2 diabetes appeared to be associated with a slightly lower risk of diverticular disease. Lack of adjustment for BMI may partially explain the conflicting findings of previous studies.
Genomic testing for children with interstitial and diffuse lung disease (chILD): parent satisfaction, understanding and health-related quality of life
Authors: Kelada Lauren , Wakefield Claire , Vidic Nada , Armstrong David S , Bennetts Bruce , Boggs Kirsten , Christodoulou John , Harrison Joanne , Ho Gladys , Kapur Nitin , Lindsey-Temple Suzanna , McDonald Tim , Mowat David , Schultz André , Selvadurai Hiran , Tai Andrew , Jaffe Adam
Published: February 2022

Objective

Research is needed to determine best practice for genomic testing in the context of child interstitial or diffuse lung disease (chILD). We explored parent’s and child’s health-related quality of life (HRQoL), parents’ perceived understanding of a genomic testing study, satisfaction with information and the study and decisional regret to undertake genomic testing.

Methods

Parents of children with diagnosed or suspected chILD who were enrolled in a genomic sequencing study were invited to complete questionnaires pretesting (T1) and after receiving the result (T2).

Results

Parents’ (T1, n=19; T2, n=17) HRQoL was lower than population norms. Study satisfaction (T1) and perceived understanding (T2) were positively correlated (rs=0.68, p=0.014). Satisfaction with information (T1 and T2) and decisional regret (T2) were negatively correlated (T1 rs=−0.71, p=0.01; T2 rs=−0.56, p=0.03). Parents reported wanting more frequent communication with staff throughout the genomic sequencing study, and greater information about the confidentiality of test results.

Conclusions

Understanding of genomic testing, satisfaction with information and participation and decisional regret are inter-related. Pretest consultations are important and can allow researchers to explain confidentiality of data and the variable turnaround times for receiving a test result. Staff can also update parents when there will be delays to receiving a result.
Association between age at onset of overweight and risk of hypertension across adulthood
Authors: Li Weijian , Fang Wei , Huang Zegui , Wang Xianxuan , Cai Zefeng , Chen Guanzhi , Wu Weiqiang , Chen Zhichao , Wu Shouling , Chen Youren
Published: February 2022

Objective

The aim of this study was to examine the association between age at onset of overweight and incident hypertension.

Methods

We analysed 4742 participants with new-onset overweight from the Kailuan study between 2006 and 2015 and and 4742 age-matched and sex-matched controls selected randomly from the same cohort but with normal weight. Participants were compared with respect to subsequent risk of hypertension, with sub-HR calculated with the Fine and Gray model, according to age of onset of overweight.

Results

Over a mean follow-up period of 5.17 years, 1642 overweight participants (34.6%) and 1293 normal-weight controls (27.3%) were subsequently diagnosed with hypertension. The median age at onset of overweight was 49.1 years. Compared with normal-weight controls, the multivariable-adjusted sub-HR for hypertension among participants with onset of overweight at 18–39 years of age, 40–49 years of age, 50–59 years of age and ≥60 years of age was 1.38 (95% CI 1.11 to 1.72), 1.27 (95% CI 1.09 to 1.49), 1.23 (95% CI 1.09 to 1.38) and 1.14 (95% CI 0.99 to 1.32), respectively. Onset of overweight in each age range was significantly associated with increased risk of hypertension, except for the group with onset at ≥60 years of age. The risk increased with each decade of attenuation of age at onset, peaking at 18–39 years of age.

Conclusions

Younger age at onset of overweight across adulthood was associated with significantly increased risk of hypertension, with the highest relative risk among participants with onset of overweight at 18–39 years of age.
Association of Mammographic Density and Benign Breast Calcifications Individually or Combined with Hypertension, Diabetes, and Hypercholesterolemia in Women ≥40 Years of Age: A Retrospective Study
Authors: Al-Mohaissen Maha , Alkhedeiri Arwa , Al-Madani Ohoud , Lee Terry , Hamdoun Anas , Al-Harbi Mohammad
Published: February 2022

Recent evidence has linked certain mammographic characteristics, including breast calcifications (Bcs) and mammographic density (MD), with atherosclerotic cardiovascular disease risk factors in women, but data are limited and inconsistent. We aimed to evaluate the association of MD and/or Bcs with hypertension, diabetes, and hypercholesterolemia in women ≥40 years of age. Through hospital electronic records, we retrospectively identified mammograms of non-pregnant women aged ≥40 years and without breast cancer and retrieved reports and relevant data. MD and Bcs were recorded; risk factor status was diagnosed based on treatment profile and clinical and laboratory data. In total, 1406 women were included. MD was inversely related to hypertension, diabetes, hypercholesterolemia, triglyceride levels, age, and body mass index (BMI) (p value for trend <0.001). Bcs were positively associated with hypertension, diabetes, hypercholesterolemia, age, BMI, and elevated creatinine (p<0.05). Controlling for age and BMI, MD category A (MD-A) was independently associated with hypercholesterolemia; Bcs were independently associated with diabetes. Combining MD-A with Bcs did not increase the odds significantly. Analysis for additive interactions revealed a significant interaction between MD-A and BMI, increasing the odds of hypertension, and a trend for increased odds of diabetes by adding MD-A and/or Bcs to BMI. Decreased MD and presence of Bcs are associated with hypertension, diabetes, and hypercholesterolemia in women ≥40 years of age. MD-A may represent a new obesity index independently associated with hypercholesterolemia and additive to hypertension risk. Bcs are independently associated with diabetes. Combining MD and Bcs did not improve the odds significantly, which may reflect mechanistic differences.
Detecting contagious spreading of urban innovations on the global city network
Authors: Kitzmann Niklas H. , Romanczuk Pawel , Wunderling Nico , Donges Jonathan F.
Published: February 2022

Only a fast and global transformation towards decarbonization and sustainability can keep the Earth in a civilization-friendly state. As hotspots for (green) innovation and experimentation, cities could play an important role in this transition. They are also known to profit from each other’s ideas, with policy and technology innovations spreading to other cities. In this way, cities can be conceptualized as nodes in a globe-spanning learning network. The dynamics of this process are important for society’s response to climate change and other challenges, but remain poorly understood on a macroscopic level. In this contribution, we develop an approach to identify whether network-based complex contagion effects are a feature of sustainability policy adoption by cities, based on dose-response contagion and surrogate data models. We apply this methodology to an exemplary data set, comprising empirical data on the spreading of a public transport innovation (Bus Rapid Transit Systems) and a global inter-city connection network based on scheduled flight routes. Although our approach is not able to identify detailed mechanisms, our results point towards a contagious spreading process, and cannot be explained by either the network structure or the increase in global adoption rate alone. Further research on the role of a city’s abstract “global neighborhood” regarding its policy and innovation decisions is thus both needed and promising, and may connect with research on social tipping processes. The methodology is generic, and can be used to compare the predictive power for innovation spreading of different kinds of inter-city network connections, e.g. via transport links, trade, or co-membership in political networks.
An iterated local search algorithm for community detection in signed networks
Authors: Chen Yiran , Kang Qinma , Duan Wenqiang , Shan Yunfan , Xiao Ran , Kang Yunfan
Published: February 2022

Community detection in signed networks has become a research hotspot in the area of network science recently. Since the classical problem has great significance for theoretical analysis and practical application, many heuristics or metaheuristics have been presented. Despite some progress and results that have been achieved, it remains an open challenge to identify community structure in large signed networks. In this paper, we propose a simple and effective iterated local search algorithm coupled with a powerful local search mechanism to solve the community detection problem. Due to the limitation of modularity in resolution, the modularity density criterion is adopted to find communities in signed networks. Extensive experiments have been conducted on synthetic and real-world networks. The statistical analyses demonstrate that the proposed algorithm can provide high-quality solutions compared to the state-of-the-art algorithms.