bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Velocity Distribution of Turbulent Flow in Pipes and Channels of Constant Cross Section
Authors: Wang Chi-Teh
Published: March 2021

This paper follows the Prandtl conception of momentum transport and gives a critical examination of the so-called Prandtl-Nikuradse formula and the von Kármán formula for the velocity distribution of the turbulent flow in tubes or channels at large Reynolds number. It shows that both formulas would not give a good picture of the turbulent flow near the center of the conduit, and indeed they actually do not. A new formula for the velocity distribution is developed from a study of the mixing-length distribution across the section. This new formula checks quite well with the experiments and yields the same skin-friction formula as derived by von Kármán and Prandtl, which itself is in very good agreement with experiments.
Calculation of the Multiple-Span Critical Speeds of Flexible Shafts by Means of Punched-Card Machines
Authors: Rankin A. W.
Published: March 2021

In turbine design, the critical speeds must be adequately spaced from the normal running speed to assure a smoothly operating unit. It is essential therefore that these critical speeds be predicted early in the design. To overcome general methods of calculating multiple-span critical speeds of irregular shafts, the author has devised a method employing standard punched-card business machines to avoid the prohibitive manual calculations hitherto involved in such work.
Internal Friction in Engineering Materials
Authors: Robertson J. M. , Yorgiadis A. J.
Published: March 2021

This paper is a report on some experiments conducted on the subject of internal friction or damping in solid engineering materials, with apparatus and technique comparatively new to the field. The use of this equipment and technique enabled the measurement of internal friction in a more direct way than most if not all of the methods used by previous investigators. In the light of the results reported, empirical relations are presented for the variation of internal friction with stress amplitude in the range of engineering stresses. These relations are compared with the findings of others.
Steady Turbulent-Flow Equations of Continuity, Momentum, and Energy for Finite Systems
Authors: Van Driest E. R.
Published: March 2021

The steady turbulent-flow equations for continuity, momentum, and energy were derived for certain finite systems. It was found that for an incompressible fluid the continuity relation contained neither nonuniform velocity-distribution correction terms nor turbulence terms, that the momentum equation involved velocity-distribution corrections and mean-square velocity fluctuations, and that the energy relation contained not only velocity-distribution corrections and mean-square terms but in addition mean-cube and double- and triple-correlation terms. The correction factors for nonuniform velocity distribution were evaluated for fully developed open channel and pipe flow. Through the momentum law the effect of turbulence was shown quantitatively in the case of the hydraulic jump in open channels and the sudden expansion in closed conduits.
Calculation of Stress in Crane Hooks
Authors: Wahl A. M.
Published: March 2021

Two methods for calculating stress in crane hooks which have given good results in practice are described. One method, based on a numerical integration of the curved-bar equations, involves only slide-rule accuracy and may be used for irregular shapes of cross section. The second or analytical method is based on an analysis of an equivalent trapezoidal section, and is applicable to hooks having sections which do not deviate too much from the trapezoidal form. Comparison of the results of the two methods when applied to actual crane hooks indicates that the more rapid analytical method is sufficiently accurate for most practical purposes.
Supersonic Nozzle Design
Authors: Puckett A. E.
Published: March 2021

A two-dimensional flow field in which the velocity is everywhere supersonic can always be represented approximately by a number of small adjacent quadrilateral flow fields in each of which the velocity and pressure are constant. These quadrilaterals must be separated by lines representing waves in the flow; changes in velocity and pressure through any wave can be computed. By increasing the number of small areas into which the complete flow field is divided, the accuracy of this approximate solutions may be increased without limit. This constitutes the “method of characteristics” solution, which has been known for many years. This method may be applied to the graphical computation of flow in a supersonic nozzle, with the particular aim of producing uniform supersonic flow at the end of the nozzle. It is pointed out that such a computation is essentially simple and rapid, and its essential features are presented in a form which, it is hoped, may be easily applied to engineering problems.
Control and Prediction of Pulsation Frequency in a Duct System
Authors: Heath W. R. , Elliot W. R.
Published: March 2021

The authors present the results of studies on compressor-duct systems which are characterized by unstable operation over some portion of the performance curves. The principles of the Helmholtz resonator are explained, and the prediction of pulsations in a duct system may be developed by considering that the system acts as a simple Helmholtz resonator. For certain cases electrical analogy is used to explain acoustical conditions in the duct. Methods of preventing pulsations are described.
A Sector-Cascade Test Rig for Measurements of Heat Transfer in Turbine Center Frames
Authors: Jagerhofer Patrick R. , Patinios Marios , Erlacher Gerhard , Glasenapp Tobias , Göttlich Emil , Farisco Federica
Published: March 2021

The turbine center frame (TCF) is an inherent component of turbofan aircraft engines and is used for connecting the high-pressure turbine (HPT) to the low-pressure turbine (LPT). Its position immediately downstream of the HPT makes it susceptible to the extremely high temperatures of future engines. Despite this, fundamental knowledge of heat transfer in TCFs and the influencing factors is still missing. This paper presents a new 45-deg sector-cascade test rig specifically designed for fundamental studies of film cooling effectiveness and heat transfer coefficient in TCFs and the development and validation of a measurement technique involving infrared thermography and heating foils. Measurements of heat transfer coefficient in the TCF were taken for two purge-to-mainstream mass flow ratios corresponding to the case of no purge and nominal (to engine operation) purge. The magnitude of the heat transfer coefficients on the hub and strut surfaces was highly influenced by the various flow structures in the passage and by the velocity variation of the mainstream flow due to the “aggressive” design of the TCF. Heat transfer on the surface of the strut was mainly governed by boundary layer behavior (laminar near the leading edge and turbulent for the rest of the strut) augmented by the effect of the secondary flow structures. Measurements of film cooling effectiveness were also taken for the single case of the nominal purge. A region of high film cooling effectiveness was observed, extending from the purge cavity exit to about 40% of the passage axial length. In this region, the effectiveness decreased with increasing axial length. On the surface of the struts and fillet radii, the film cooling effectiveness was found to be zero. This was attributed to the effect of the horseshoe vortex that sweeps the purge flow away from the strut surface and dilutes it by continuously entraining hot mainstream flow.
High-Fidelity Simulations of Multi-Jet Impingement Cooling Flows
Authors: Otero-Pérez J. Javier , Sandberg Richard D. , Mizukami Satoshi , Tanimoto Koichi
Published: March 2021

This article shows the first parametric study on turbulent multi-jet impingement cooling flows using large-eddy simulations (LES). We focus on assessing the influence of the inter-jet distance and the cross-flow conditions on the heat transfer at the impingement wall. The LES setup is thoroughly validated with both experimental and direct numerical simulation data, showing an excellent agreement. The inter-jet distance effect on the heat transfer is studied comparing three different distances, where the full Nusselt number profile decreases in amplitude when the jet distance is increased. To evaluate the cross-flow effects, we prescribe both laminar and turbulent inflow conditions at different cross-flow magnitudes ranging between 20% and 40% of the impinging jet speed. Large cross-flow intensities cause a jet deflection that reduces the maxima in the Nusselt number distribution, and it increases the heat transfer in the areas of the wall less affected by the jet impingement. Adding realistic turbulent fluctuations to the inflow enhances the cross-flow effects on the heat transfer at the impingement wall.
Heat Transfer in a Rotating, Two-Pass, Variable Aspect Ratio Cooling Channel With Profiled V-Shaped Ribs
Authors: Chen I-Lun , Sahin Izzet , Wright Lesley M. , Han Je-Chin , Krewinkel Robert
Published: March 2021

The thermal performance of two V-type rib configurations is measured in a rotating, two-pass cooling channel. The coolant travels radially outward in the rectangular first pass (aspect ratio (AR—channel width:height) = 4:1) and radially inward in the second pass (AR = 2:1). Both the passages are oriented 90 deg to the direction of rotation. The leading surface (LS) and trailing surface (TS) of the channel are roughened with V-type ribs. The first V-shaped configuration has a narrow gap at the apex of the V. The configuration is modified by off-setting one leg of the V to create a staggered discrete, V-shaped configuration. The ribs are oriented 45 deg relative to the streamwise coolant direction. The heat transfer enhancement and frictional losses are measured with varying Reynolds and rotation numbers. The Reynolds number varies from 10,000 to 45,000 in the AR = 4:1 first pass; this corresponds to 16,000 to 73,500 in the AR = 2:1 second pass. The maximum rotation numbers are 0.39 and 0.16 in the first and second passes, respectively. The heat transfer enhancement on both the leading and trailing surfaces of the first pass of the 45 deg V-shaped channel is slightly reduced with rotation. In the second pass, the heat transfer increases on the leading surface, while it decreases on the trailing surface. The 45 deg staggered, discrete V-shaped ribs provide increased heat transfer and thermal performance compared to the traditional V-shaped and standard, 45 deg angled rib turbulators.
Experimental Study on Film Cooling Effectiveness of Blade With Chevron-Shaped Holes Under Wake Influence
Authors: Li Ji-Chen , Zhu Hui-Ren , Liu Cun-Liang , Ye Lin , Zhou Dao-En
Published: March 2021

Gas turbines have been widely used. With the continuous improvement of the performance of gas turbines, the turbine inlet temperature has greatly exceeded the heat-resistance limit of the turbine blade material, so advanced cooling technology is required. The film cooling effectiveness distribution over the blade under the effect of wake was obtained by the pressure-sensitive paint (PSP) technique. The test blade has five rows of chevron film holes on the pressure side, three rows of cylindrical film holes on the leading edge, and three rows of chevron film holes on the suction side. The mainstream Reynolds number is 130,000 based on the blade chord length, and the mainstream turbulence intensity is 2.7%. The upstream wake was simulated by the spoken-wheel type wake generator. The film cooling effectiveness was measured at three wake Strouhal numbers (0, 0.12, and 0.36) and three mass flux ratios (MFR1, MFR2, and MFR3). The results show that the increase of mass flux ratio leads to a decrease of the film cooling effectiveness on the suction surface. In the wake condition, the effect of mass flux ratio is weakened. Wake leads to a marked decrease of the film cooling effectiveness over most blade surface except for the surface near leading edge on the pressure surface. In the high mass flux ratio condition, the effect of wake on the film cooling effectiveness is weakened on the suction surface and strengthened on the pressure surface.
Free-Stream Turbulence-Induced Boundary-Layer Transition in Low-Pressure Turbines
Authors: Ðurović Kristina , De Vincentiis Luca , Simoni Daniele , Lengani Davide , Pralits Jan , Henningson Dan S. , Hanifi Ardeshir
Published: March 2021

The aerodynamic efficiency of turbomachinery blades is profoundly affected by the occurrence of laminar-turbulent transition in the boundary layer since skin friction and losses rise for the turbulent state. Depending on the free-stream turbulence level, we can identify different paths toward a turbulent state. The present study uses direct numerical simulation as the primary tool to investigate the flow behavior of the low-pressure turbine blade. In the simulations, the flow past only one blade is computed, with periodic boundary conditions in the cross-flow directions to account for the cascade. Isotropic homogeneous free-stream turbulence is prescribed at the inlet. The free-stream turbulence is prescribed as a superposition of Fourier modes with a random phase shift. Two levels of the free-stream turbulence intensity were simulated (Tu=0.19% and 5.2%), with the integral length scale being 0.167c, at the leading edge. We observed that in the case of low free-stream turbulence on the suction side, the Kelvin–Helmholz instability dominated the transition process and full-span vortices were shed from the separation bubble. Transition on the suction side proceeded more rapidly in the high-turbulence case, where streaks broke down into turbulent spots and caused bypass transition. On the pressure side, we have identified the appearance of longitudinal vortical structures, where increasing the turbulence level gives rise to more longitudinal structures. We note that these vortical structures are not produced by Görtler instability.
Sensitivity of the Toe Height to Multijoint Angular Changes in the Lower Limbs During Unobstructed and Obstructed Gait
Authors: Cui Chuyi , Muir Brittney , Rietdyk Shirley , Haddad Jeffrey , van Emmerik Richard , Ambike Satyajit
Published: March 2021

Tripping while walking is a main contributor to falls across the adult lifespan. Trip risk is proportional to variability in toe clearance. To determine the sources of this variability, the authors computed for 10 young adults the sensitivity of toe clearance to 10 bilateral lower limb joint angles during unobstructed and obstructed walking when the lead and the trail limb crossed the obstacle. The authors computed a novel measure—singular value of the appropriate Jacobian—as the combined toe clearance sensitivity to 4 groups of angles: all sagittal and all frontal plane angles and all swing and all stance limb angles. Toe clearance was most sensitive to the stance hip ab/adduction for unobstructed gait. For obstructed gait, sensitivity to other joints increased and matched the sensitivity to stance hip ab/adduction. Combined sensitivities revealed critical information that was not evident in the sensitivities to individual angles. The combined sensitivity to stance limb angles was 84% higher than swing limb angles. The combined sensitivity to the sagittal plane angles was lower than the sensitivity to the frontal plane angles during unobstructed gait, and this relation was reversed during obstacle crossing. The results highlight the importance of the stance limb joints and indicate that frontal plane angles should not be ignored.
Wax-wetting sponges for oil droplets recovery from frigid waters
Authors: Cherukupally P. , Sun W. , Williams D. R. , Ozin G. A. , Bilton A. M.
Published: March 2021

We designed nanostructured wax-wetting sponges for reclaiming wastewater in ice-cold Arctic and Canadian environments.
Evaluation of the Performance of the Loopamp Trypanosoma cruzi Detection Kit for the Diagnosis of Chagas Disease in an Area Where It Is Not Endemic, Spain
Authors: Flores-Chavez Maria D. , Abras Alba , Ballart Cristina , Ibáñez Perez Ismael , Perez-Gordillo Pilar , Gállego Montserrat , Muñoz Carmen , Moure Zaira , Sulleiro Igual Elena , Nieto Javier , García Diez Emilia , Cruz Israel , Picado Albert
Published: March 2021

In Spain, PCR is the tool of choice for the diagnosis of congenital Chagas disease (CD) and serology for diagnosing chronic CD. A loop-mediated isothermal amplification test for
Trypanosoma cruzi
DNA detection showed good analytical performance and ease of use.
SARS-CoV-2 Rapidly Adapts in Aged BALB/c Mice and Induces Typical Pneumonia
Authors: Zhang Yufei , Huang Kun , Wang Ting , Deng Fei , Gong Wenxiao , Hui Xianfeng , Zhao Ya , He Xinlin , Li Chengfei , Zhang Qiang , Chen Xi , Lv Changjie , Lin Xian , Yang Ying , Sun Xiaomei , Shi Zhengli , Chen Huanchun , Zou Zhong , Jin Meilin
Published: March 2021

Aged BALB/c mice are in use as a model of disease caused by SARS-CoV-2. Our research demonstrated SARS-CoV-2 can rapidly adapt in aged BALB/c mice through causing mutations at the RBD of the S protein.
Complete Genome Sequence of
Kaistia
sp. Strain 32K, Isolated from Soil as a Mixed Single Colony with
Methylobacterium
sp. Strain ME121
Authors: Ito Masahiro , Shimizu Tetsu , Nakamura Akira
Published: March 2021

Kaistia
sp. strain 32K, an aerobic Gram-negative bacterium, was isolated from soil in Japan. Here, we report the complete genome sequence of this bacterium, which has a 5.4-Mbp genome sequence, containing 4,919 protein-coding sequences.
Draft Genome Sequence of the Putative Endophytic Bacterium Pantoea agglomerans R6, Associated with Lactuca serriola from South Africa
Authors: Istain Brandon , Mokgokong Prudent S. , Wu Ruomou , Mia Junaid , Gokul Arun , Mendoza-Cozatl David , Du Plessis Morné , Keyster Marshall
Published: March 2021

Here, we present the draft genome sequence (∼4.7 Mb) of the endopyhtic bacterium
Pantoea agglomerans
strain R6, which was isolated from surface-sterilized roots of
Lactuca serriola
(prickly lettuce).
Complete Genome Sequence of Thermus thermophilus Strain HB5018, Isolated from Mine Hot Spring in Japan
Authors: Miyazaki Kentaro , Moriya Toshiyuki , Nemoto Naoki , Oshima Tairo , Yura Kei , Bessho Yoshitaka
Published: March 2021

We isolated
Thermus thermophilus
strain HB5018 from Mine Hot Spring in Japan, where the type strain HB8 was isolated nearly half a century ago. The complete genome sequence of HB5018 showed 99.1% average nucleotide identity with HB8, suggesting strict species conservation in the habitat over the past 50 years.
Complete Genome Sequence Obtained by Nanopore and Illumina Hybrid Assembly of Xanthomonas arboricola pv. juglandis CPBF 427, Isolated from Buds of a Walnut Tree
Authors: Teixeira Miguel , Fernandes Camila , Chaves Cátia , Pinto Joana , Tavares Fernando , Fonseca Nuno A.
Published: March 2021

We report the genome sequence of
Xanthomonas arboricola
pv.
juglandis
strain CPBF 427, which was isolated from early-season buds of a diseased walnut tree, suggesting overwinter potential. This study provides a consistent genomic reference for this pathovar and may contribute to addressing the overwinter survival of these walnut pathogens.
Draft Genome Sequence of
Dietzia
sp. Strain SYD-A1, Isolated from Coal Seam Formation Water
Authors: Vick Silas H. W. , Greenfield Paul , Tetu Sasha G. , Midgley David J. , Paulsen Ian T.
Published: March 2021

Subsurface coal seams harbor an array of diverse microbial species subsisting as a community on the organic matter present in coal. Here, we present the annotated genome sequence of
Dietzia
sp. strain SYD-A1, a bacterium isolated from a terrestrial subsurface coal seam in New South Wales (NSW), Australia.
Complete Genome Sequences of Staphylococcus argenteus Tokyo13064 and Tokyo13069, Isolated from Specimens Obtained during a Food Poisoning Outbreak in Tokyo, Japan
Authors: Suzuki Yasunori , Kubota Hiroaki , Kakuda Tsutomu , Takai Shinji , Sadamasu Kenji
Published: March 2021

The complete genome sequences of two
Staphylococcus argenteus
strains, Tokyo13064 and Tokyo13069, isolated from human feces and suspected causative foods during a staphylococcal food poisoning outbreak, consist of 2,750,811-bp and 2,751,556-bp circular chromosomes and 2,543 and 2,548 genome annotation-predicted coding DNA sequences, respectively, with 19 rRNAs, 61 tRNAs, and 1 CRISPR each.
Soil Metagenome Sequences from a Geothermal Site at Mount Melbourne in Antarctica
Authors: Park Mira , Choe Yong-Hoe , Kim Mincheol
Published: March 2021

Here, we examined two soil metagenome data sets obtained from a geothermal site at the summit of Mount Melbourne in Antarctica. The geothermal soil microbiome exhibits very unique features of prokaryotic diversity and functions, which will provide deeper insight into the adaptation and evolution of soil microbes in Antarctic geothermal habitats.
Mapping Gene-by-Gene Single-Nucleotide Variation in 8,535 Mycobacterium tuberculosis Genomes: a Resource To Support Potential Vaccine and Drug Development
Authors: Papakonstantinou Danai , Dunn Steven J. , Draper Simon J. , Cunningham Adam F. , O’Shea Matthew K. , McNally Alan
Published: March 2021

Tuberculosis is an infectious disease caused by the bacterium
Mycobacterium tuberculosis
. In the first half of the 20th century, the discovery of the
Mycobacterium bovis
BCG vaccine and antituberculous drugs heralded a new era in the control of TB.
Features of the Behavior of a Polymer Solution Jet in Electrospinning
Authors: Subbotin A. V.
Published: March 2021

Using the numerical analysis of the force balance equation and the rheological equation of the model of finitely extensible chains, the dynamics of a charged jet during the electrospinning of a polymer solution and the orientation of macromolecules in the jet are studied. In fairly weak electric fields, the jet always remains rectilinear, while in strong fields the straight section of the jet has a finite length, after which the motion of the jet becomes unstable. This behavior is due to the competition between inertial and viscoelastic forces, with viscoelasticity dominating in strong fields. It is found that polymer chains in the jet are strongly stretched along the flow direction.
Production of a Cloned Offspring and CRISPR/Cas9 Genome Editing of Embryonic Fibroblasts in Cattle
Authors: Singina G. N. , Sergiev P. V. , Lopukhov A. V. , Rubtsova M. P. , Taradajnic N. P. , Ravin N. V. , Shedova E. N. , Taradajnic T. E. , Polejaeva I. A. , Dozev A. V. , Brem G. , Dontsova O. A. , Zinovieva N. A.
Published: March 2021

Somatic Cell Nuclear Transfer (SCNT) technique was used to produce the first viable cloned cattle offspring in Russia. Whole-genome SNP genotyping confirmed that the cloned calf was identical to the fibroblast cell line that was used for SCNT. CRISPR/Cas9 approach was subsequently used to knock out genes for beta-lactoglobulin gene (PAEP) and the beta-lactoglobulin-like protein gene (LOC100848610) in the fibroblast cells. Gene editing (GE) efficiency was 4.4% for each of these genes. We successfully obtained single-cell-derived fibroblast colonies containing PAEP and LOC100848610 knockouts, which will be used to produce beta-lactoglobulin-deficient cattle.
Methane Adsorption on Microporous Carbon Adsorbent Prepared from Thermochemically Activated Wood
Authors: Fomkin A. A. , Dubovik B. A. , Limonov N. V. , Pribylov A. A. , Pulin A. L. , Men’shchikov I. E. , Shkolin A. V.
Published: March 2021

Abstract—

An EC-103 microporous carbon adsorbent was synthesized from wood using thermochemically activation with Н3РО4 as an activating agent. Methane adsorption on the EC-103 adsorbent was studied within the temperature range from 303 to 333 K and at pressures up to 40 MPa. The total volume of sorbing pores was 1.71 cm3/g. The maximum values of methane adsorption were obtained at the temperature of 303 K and pressure of 40 MPa. The differential molar isosteric heat of methane adsorption 14.5 mmol/g (23.2 wt %) was on the average of 12−14 kJ/mol. Methane adsorption on the EC-103 adsorbent was calculated based on the Dubinin theory of volume filling of micropores (TVFM). It was shown that the Dubinin-Radushkevich equation and basic TVFM pattern provided the best description of experimental data on methane adsorption with the use of only the standard structural and energy characteristics of the adsorbent.
Unicortical sternal graft reconstruction for anterior sternoclavicular joint instability
Authors: Parker Kate M , Somerson Jeremy S , Warme Winston J
Published: March 2021

Sternoclavicular joint (SCJ) injury represents 3%–5% of all shoulder girdle injuries, yet can produce significant pain and disability. While conservative management improves symptoms in most cases, surgical intervention may be indicated for patients with symptoms recalcitrant to nonoperative treatment. A wide range of surgical stabilisation techniques is documented in the literature; however, the scarcity of SCJ pathology has hindered development of a ‘gold standard’.

We present a minimalistic medial clavicle osteoplasty and SCJ reconstruction using semitendinosus autograft anchored with unicortical sternal tunnels in the 54 years old with chronic SCJ instability. This technique can be performed safely, resulting in joint stability and pain reduction, while avoiding risks and complications noted in the literature with other techniques.
Fumarate hydratase-deficient renal cell carcinoma presenting as pelvicalyceal filling defect: an unusual presentation of a rare disease
Authors: Ajjikuttira Aiyapa , Sharma Pranav , Joshi Andre , Rhee Handoo
Published: March 2021

A 75-year-old man was referred to our urology service with painless haematuria. The delayed phase on a subsequent computed tomography (CT) abdomen and pelvis showed a filling defect in the left renal pelvicalyceal system, suspicious for a transitional cell carcinoma. The patient underwent ureteroscopic biopsy suggestive of a papillary neoplasia, before progressing to a laparoscopic radical left nephrouretectomy. Final histology revealed a fumarate hydratase-deficient renal cell carcinoma with clear margins. The patient was subsequently referred for genetic counselling.
A case of cystic lymphatic malformation mimicking acute appendicitis in an adult patient: a rare diagnostic pitfall
Authors: Joret Maximilian Olavi , Nanayakkara Asanga , Kulasegaran Suheelan , Martin Richard
Published: March 2021

Abdominal cystic lymphatic malformations are rare pathological entities of uncertain aetiology that usually present in early childhood with indolent abdominal distention. We report the case of a 17-year-old man who presented to our hospital with acute right lower quadrant pain, nausea and anorexia. His blood tests revealed a raised white cell count and elevated inflammatory markers. Clinical examination revealed signs of localised right lower quadrant peritonism. A diagnosis of clinical appendicitis was made, and in keeping with local management protocols, the patient proceeded to theatre for a diagnostic laparoscopy without radiological investigations. Operative findings yielded a normal appendix and a large abdominal cystic malformation. This article highlights the need to keep a broad differential diagnosis when performing surgery on patients with clinically presumed appendicitis and the importance of radiological investigations in clinical decision-making, we also review abdominal cystic lymphatic malformations as a rare diagnostic pitfall.
Streptococcus pneumoniaepurulent pericarditis secondary to influenza A infection and pneumococcal pneumonia in an immunocompetent woman
Authors: Houlihan Elaine , McLoughlin Raymond , Waldron Ruth
Published: March 2021

A 44-year-old previously well woman presented with features of respiratory sepsis including a productive cough and fevers, with a recent preceding influenza-like illness. She was diagnosed with community-acquired pneumonia on chest radiograph, influenza infection via nasopharyngeal swab andStreptococcus pneumoniaebloodstream infection with associated purulent pericarditis. She was managed with pericardial drainage and concurrent treatment with antibiotics and made an excellent recovery. This case highlights the complications of both influenza andS. pneumoniaeinfections, and the importance of prevention via vaccination.
Across-subjects multiple baseline trial of exposure-based cognitive-behavioral therapy for severe irritability: a study protocol
Authors: Naim Reut , Kircanski Katharina , Gold Andrea , German Ramaris E , Davis Mollie , Perlstein Samantha , Clayton Michal , Revzina Olga , Brotman Melissa A
Published: March 2021

Introduction

Irritability is defined as a tendency towards anger in response to frustration. Clinically, impairing irritability is a significant public health problem. There is a need for mechanism-based psychotherapies targeting severe irritability as it manifests in the context of disruptive mood dysregulation disorder (DMDD). This study protocol describes a randomised multiple baseline design testing the preliminary efficacy of a new treatment, exposure-based cognitive-behavioral therapy for severe irritability in youth, which also integrates components of parent management training. We will investigate associations of this intervention with primary clinical measures, as well as ecological momentary assessment measures.

Methods and analysis

Forty youth will be enrolled. Participants, aged 8–17 years, must present at least one of two core symptoms of DMDD: abnormal mood or increased reactivity to negative emotional stimuli, with severe impairment in one domain (home, school, peers) and moderate in another, or moderate impairment in at least two domains. Each participant is randomised to a 2-week, 4-week or 6-week baseline observation period, followed by 12 active treatment sessions. Clinical ratings are conducted at baseline, biweekly (clinician), weekly (parent/child) throughout treatment, post-treatment, and 3-month and 6-month follow-up (clinician). Clinician ratings on the Affective Reactivity Index and Clinical Global Impressions-Improvement scale for DMDD are our primary outcome measures. Secondary outcome measures include parent and child reports of irritability. Post hoc additional symptom measures include clinician, parent and self-ratings of depression, anxiety and overall functional impairment. Prospective, digitally based event sampling of symptoms is acquired for a week pre-treatment, mid-treatment and post-treatment. Based on our pathophysiological model of irritability implicating frustrative non-reward, aberrant threat processing and instrumental learning, we probe these three brain-based targets using functional MRI paradigms to assess target engagement.

Ethics and dissemination

The research project and all related materials were submitted and approved by the appropriate Institutional Review Board (IRB) of the National Institute of Mental Health (NIMH).

Trial registration numbers

NCT02531893andNCT00025935.
Systematic review protocol to assess artificial intelligence diagnostic accuracy performance in detecting acute ischaemic stroke and large-vessel occlusions on CT and MR medical imaging
Authors: Kundeti Srinivasa Rao , Vaidyanathan Manikanda Krishnan , Shivashankar Bharath , Gorthi Sankar Prasad
Published: March 2021

Introduction

The use of artificial intelligence (AI) to support the diagnosis of acute ischaemic stroke (AIS) could improve patient outcomes and facilitate accurate tissue and vessel assessment. However, the evidence in published AI studies is inadequate and difficult to interpret which reduces the accountability of the diagnostic results in clinical settings. This study protocol describes a rigorous systematic review of the accuracy of AI in the diagnosis of AIS and detection of large-vessel occlusions (LVOs).

Methods and analysis

We will perform a systematic review and meta-analysis of the performance of AI models for diagnosing AIS and detecting LVOs. We will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols guidelines. Literature searches will be conducted in eight databases. For data screening and extraction, two reviewers will use a modified Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist. We will assess the included studies using the Quality Assessment of Diagnostic Accuracy Studies guidelines. We will conduct a meta-analysis if sufficient data are available. We will use hierarchical summary receiver operating characteristic curves to estimate the summary operating points, including the pooled sensitivity and specificity, with 95% CIs, if pooling is appropriate. Furthermore, if sufficient data are available, we will use Grading of Recommendations, Assessment, Development and Evaluations profiler software to summarise the main findings of the systematic review, as a summary of results.

Ethics and dissemination

There are no ethical considerations associated with this study protocol, as the systematic review focuses on the examination of secondary data. The systematic review results will be used to report on the accuracy, completeness and standard procedures of the included studies. We will disseminate our findings by publishing our analysis in a peer-reviewed journal and, if required, we will communicate with the stakeholders of the studies and bibliographic databases.

PROSPERO registration number

CRD42020179652.
The control of pain due to dentin hypersensitivity in individuals with molar–incisor hypomineralisation: a protocol for a randomised controlled clinical trial
Authors: Sobral Ana Paula Taboada , Santos Elaine Marcilio , Aranha Ana Cecilia , Soares Paulo Vinícius , Moriyama Caroline Moraes , Gonçalves Marcela Leticia Leal , Ribeiro Rodrigo Alves , Motta Lara Jansiski , Horliana Anna Carolina Ratto Tempestini , Fernandes Kristianne Porta Santos , Mesquita-Ferrari Raquel Agnelli , Bussadori Sandra Kalil
Published: March 2021

Introduction

Dentin hypersensitivity (DH) is defined as high sensitivity of the vital dentin when exposed to thermal, chemical or tactile stimuli. Two mechanisms are required for the occurrence of DH: (1) the dentin must be exposed and (2) the dentinal tubules must be open and connected to the pulp. Molar–incisor hypomineralisation (MIH) is a qualitative abnormality of a genetic origin that affects tooth enamel and, in most cases, is accompanied by DH. The control of tooth sensitivity is fundamental to the successful treatment of MIH. The aim of the proposed randomised, controlled, clinical trial is to evaluate the effectiveness of different protocols for the control of DH in patients with teeth affected by MIH.

Methods and analysis

One hundred and forty patients who meet the inclusion criteria will be allocated to four groups. Group 1 will be the control group (placebo). In Group 2, sensitive teeth will be sealed with PermaSeal (Ultradent). In Group 3, sensitive teeth will receive low-level laser (LLL, AsGaAl) at a wavelength of 780 nm (Laser XT Therapy, DMC, São Carlos, Brazil). In Group 4, sensitive teeth will be treated with both LLL and PermaSeal (Ultradent). DH will be evaluated 15 min after the application of the treatments and the patients will be reevaluated 1 week, 1 month, 3 months and 6 months after the treatments. The primary outcome of this study is change in pain/sensitivity, when evaluated through a Visual Analogue Scale, to determine the effectiveness of the proposed treatments, as well as differences among the evaluation times for each proposed treatment.

Ethics and dissemination

This protocol has been ethically approved by the local medical ethical committee (protocol number: 4.020.261). Results will be submitted to international peer-reviewed journals and presented at international conferences.

Trial registration number

NCT04407702.
Effectiveness of a multifaceted intervention to improve emergency department care of low back pain: a stepped-wedge, cluster-randomised trial
Authors: Coombs Danielle M , Machado Gustavo C , Richards Bethan , Needs Chris , Buchbinder Rachelle , Harris Ian A , Howard Kirsten , McCaffery Kirsten , Billot Laurent , Edwards James , Rogan Eileen , Facer Rochelle , Li Qiang , Maher Christopher G
Published: March 2021

Background

Overuse of lumbar imaging is common in the emergency department (ED). Few trials have examined interventions to address this. We evaluated the effectiveness of a multifaceted intervention to implement guideline recommendations for low back pain in the emergency department.

Methods

We conducted a stepped-wedge, cluster-randomised trial in four EDs in New South Wales, Australia. After a 13-month control phase of usual care, the EDs received a multifaceted intervention to support guideline-endorsed care in a random order, based on a computer-generated random sequence, every 4 weeks over a 4-month period. All sites were followed up for at least 3 months. The primary outcome was the proportion of low back pain presentations receiving lumbar imaging. Secondary healthcare utilisation outcomes included prescriptions of opioid and non-opioid pain medicines, inpatient admissions, length of ED stay, specialist referrals and re-presentations. Clinician beliefs and knowledge about low back pain care were measured before and after the intervention. Patient-reported pain, disability, quality of life and satisfaction were measured at 1, 2 and 4 weeks post ED presentation.

Results

A total of 269 ED clinicians and 4625 episodes of care for low back pain (4491 patients) were included. The data did not provide clear evidence that the intervention reduced lumbar imaging (OR 0.77; 95% CI 0.47 to 1.26; p=0.29). It did reduce opioid use (OR 0.57; 95% CI 0.38 to 0.85; p=0.006) and improved clinicians’ beliefs (mean difference (MD), 2.85; 95% CI 1.85 to 3.85; p<0.001; on a scale from 9 to 45) and knowledge about low back pain care (MD, 0.48; 95% CI 0.13 to 0.83; p<0.01; on a scale from 0 to 11). There was no difference in pain scores at 1-week follow-up (MD, 0.04; 95% CI −1.00 to 1.08; p=0.94; on a scale from 0 to 10). A similar trend was observed for all other patient-reported outcomes and time points. This study found no effect on the other secondary healthcare utilisation outcomes.

Conclusion

It is uncertain if a multifaceted intervention to implement guideline recommendations for low back pain care decreased lumbar imaging in the ED; however, it did reduce opioid prescriptions without adversely affecting patient outcomes.

Trial registration numberACTRN12617001160325.
Naltrexone for cholestatic itch: a systematic review
Authors: Murray-Brown Fay Louise
Published: March 2021

Background

Cholestatic itch is caused by intrahepatic liver diseases, such as primary biliary cirrhosis and extrahepatic obstruction of the biliary tree, often caused by tumours. The pathophysiology of cholestatic itch is complex and no single treatment has proved definitive. Naltrexone is an opioid receptor antagonist, which reduces central opioidergic tone, believed to be raised in patients with cholestatic pruritus.

Aim

To review and assess the efficacy of oral naltrexone for the treatment of cholestatic itch.

Methods

Search of electronic databases, grey literature, clinical trials registries and handsearching for studies including naltrexone for cholestatic itch. Full papers were obtained if relevant and studies graded.

Results

Thirteen papers were included in the analysis, including three randomised controlled trials, one controlled clinical trial, one open-label pilot study, seven case reports and one retrospective notes review. All studies found naltrexone to be effective in relieving pruritus. In all five studies performing statistical analysis, naltrexone significantly reduced pruritus compared with baseline. 37% of patients reported side effects, notably opioid withdrawal-type reactions and recurrence of previous pain, from all pathologies.

Conclusions

Oral naltrexone therapy helps relieve cholestatic itch and although it should be used with caution in patients using exogenous opioids for analgesia, it should be considered when treating refractory pruritus in patients with end-stage liver disease.
Traum'cast: an online, open-access educational video podcast series for teaching military trauma care to all healthcare providers
Authors: Boutonnet Mathieu , Benbrika Widad , Facione Julia , Travers Stéphane , Boddaert Guillaume , Colas Marie-Dominique , Hornez Emmanuel , Mathieu Laurent , de Régloix Stanislas , Daban Jean-Louis , Leclerc Thomas , Pasquier Pierre , Ausset Sylvain
Published: March 2021

The aim of this paper was to describe the development of ‘Traum’cast’, an ambitious project to create a high-quality, open-access, 12-week video podcast programme providing evidence-based continuing medical education for civilian and military healthcare practitioners dedicated to the management of trauma caused by weapons of war. The management of such patients became a particular public health issue in France following the 2015 terrorist attacks in Paris, which highlighted the need for all healthcare professionals to have appropriate knowledge and training in such situations. In 2016, the French Health General Direction asked the French Military Medical Service (FMMS) to create a task force and to use its unique and considerable experience to produce high-quality educational material on key themes including war injuries, combat casualty care, triage, damage control surgery, transfusion strategies, psychological injury and rehabilitation. The material was produced by FMMS and first broadcast in French and for free, on the official FMMS YouTube channel in September 2020. Traum’cast provides evidence-based continuing medical education for civilian and military healthcare practitioners. Traum’cast is an educational innovation that meets a public health requirement.
Relations among sensitivity, specificity and predictive values of medical tests based on biomarkers
Authors: Wang Hongyue , Wang Bokai , Zhang Xunan , Feng Changyong
Published: March 2021

Diagnostic tests are usually based on some quantitative biomarkers. Two key parameters used to characterise the quality of a test are test sensitivity and specificity. Predictive values of the disease status based on test results are also of interest in medical research and public health management. In this paper, we study the relations among sensitivity, specificity and predictive values of the test. The core concept is risk function, which is assumed to be an increasing function of the biomarker. Our results show that test sensitivity and specificity change in opposite directions. The positive predictive value and the sensitivity also change in opposite directions. Likewise, the negative predictive value and the specificity change in opposite directions.
‘Who is going to put their life on the line for a dollar? That’s crazy’: community perspectives of financial compensation in clinical research
Authors: Devlin Amie , Brownstein Kirsten , Goodwin Jennifer , Gibeau Emily , Pardes Mariana , Grunwald Heidi , Fisher Susan
Published: March 2021

Background

Financial compensation of research participants has been standard practice for centuries, however, there is an ongoing debate among researchers and ethicists regarding the ethical nature of this practice. While these debates develop ethical arguments and theories, they fail to incorporate input from those most affected by financial compensation: potential research participants.

Methods

To identify attitudes surrounding clinical research, participants of a long-standing cohort completed a one-time interview. Open-ended questions stimulated a participant-driven discussion surrounding medical research. Following a grounded theory methodology, 58 semistructured interview transcripts were coded, focusing on attitudes surrounding financial compensation of research participants.

Results

Of the interviews coded, the majority of participants identified as Black/African American (n=44) and were women (n=40). Five major themes emerged. In support of financial compensation, participants felt that study participants should be compensated for time, effort and risk. However, participants were concerned that compensation may differentially impact low-income populations and entice them to hide potentially harmful side effects. Participants also mentioned that financial compensation may invalidate study results if participants knowingly provide false information to subvert inclusion/exclusion criteria.

Conclusion

The emergence of both positive and negative themes reiterates the complicated issue of providing financial compensation for study participation. While compensation as a motivator for research participation raises ethical concerns, participants discussed weighing the benefits with the risks in order to make an informed decision. To avoid paternalistic behaviours, research staff must allow potential research participants to review the available information and make the decision that best reflects their wishes.
Personal perspectives: having the time to observe the patient
Authors: Taylor-Robinson Simon D
Published: March 2021

Being a medically qualified patient can be an unpleasant experience for a person who is used to making decisions. For the most part, this applies to the vast majority of doctors and other healthcare professionals. Becoming passive and surrendering the decision-making process to others is alien to the medical culture we were taught. However, when as a hospitalised medically qualified patient, one sees fellow patients in difficulty, or deteriorating clinically, unnoticed by medical staff, the question of whether it is ethical to intervene arises. I report my views on this as a largely passive, but still actively thinking patient.
Reviewing the use and quality of machine learning in developing clinical prediction models for cardiovascular disease
Authors: Allan Simon , Olaiya Raphael , Burhan Rasan
Published: March 2021

Cardiovascular disease (CVD) is one of the leading causes of death across the world. CVD can lead to angina, heart attacks, heart failure, strokes, and eventually, death; among many other serious conditions. The early intervention with those at a higher risk of developing CVD, typically with statin treatment, leads to better health outcomes. For this reason, clinical prediction models (CPMs) have been developed to identify those at a high risk of developing CVD so that treatment can begin at an earlier stage. Currently, CPMs are built around statistical analysis of factors linked to developing CVD, such as body mass index and family history. The emerging field of machine learning (ML) in healthcare, using computer algorithms that learn from a dataset without explicit programming, has the potential to outperform the CPMs available today. ML has already shown exciting progress in the detection of skin malignancies, bone fractures and many other medical conditions. In this review, we will analyse and explain the CPMs currently in use with comparisons to their developing ML counterparts. We have found that although the newest non-ML CPMs are effective, ML-based approaches consistently outperform them. However, improvements to the literature need to be made before ML should be implemented over current CPMs.
Anchorage capacity of headed bars in steel fiber reinforced concrete
Authors: Sachdeva Payal , Roy A.B.D. , Kwatra Naveen
Published: March 2021

Headed bars (HB) with different head shapes (Square, Circular, and Rectangular) and bar diameters (db: 16, 20, and 25 mm) embedded in steel fiber reinforced concrete have been subjected to pull-out test. The influence of head shapes, concrete compressive strength (M20 and M40), db, and steel fibers (0, 0.5, 1, and 1.5%) on the anchorage capacity of HB have been evaluated. Numerical model for improving the anchorage capacity of HB has also been proposed. Results have revealed that the anchorage capacity of HB increases with the increase in concrete compressive strength, db, and steel fibers, which have been validated by nonlinear regression analysis using dummy variables. Two failure modes namely, steel and concrete-blowout have been observed and the prevailing mode of failure is steel failure. Based on load–deflection curves and derived descriptive equations, it is observed that the circular HB has displayed the highest peak load.