bluuebunny/crossref_metadata_2025 huggingface dataset:
Wall Bounded Flows and a General Proof of the Validity of the Universal Logarithmic Law of the Wall
Authors: Epple Philipp , Steppert Michael , Malcherek Andreas
Published: October 2021

The logarithmic law of the wall is usually derived for the flat plate assuming stationary, two-dimensional fully developed flow with no external pressure gradient. The Prandtl mixing length model for the turbulence is applied, which assumes homogeneous turbulence and two empirical constants, and the logarithmic wall law is derived. It is than stated in the textbooks that it is universally valid without a proof. As a justification experimental evidence is shown. First this proof will be shown in detail. Than a more general approach based on similarity considerations is made to show the universal validity of the logarithmic law of the wall.

Starting from the Navier-Stokes equation a general non dimensional form of this equation is derived showing its dependency from four non-dimensional numbers, the Strouhal, Euler, Reynolds and the Froude number.

Then wall bounded laminar flows are analyzed by dimensional analysis. The laminar boundary length and time scales are derived and used to non-dimensionalize the Navier-Stokes equation. With this specific non-dimensionalization for the laminar boundary layer a more specific non dimensional Navier-Stokes equation is derived. Then the high Reynolds limit is taken with considerations of orders of magnitude and the boundary layer equations are derived.

Finally, for turbulent near wall flows a dimensional analysis is made and the corresponding near wall non-dimensional velocities and coordinates y+ and u+ are derived from the Buckingham-Π theorem. Using these variables to non-dimensionalize the Navier-Stokes equations in the near wall turbulent region the third author Malcherek showed that the so derived non-dimensional Navier-Stokes equations do not depend on any non-dimensional number and has a unique solution. Hence, the logarithmic law of the wall must be universally valid, without any simplification, any turbulence model, empirical constant or further assumptions.

In such a way the students do not have to believe anymore in the universality of the logarithmic law of the wall based on empirical evidence only, now this fact has been proven by the third author Malcherek and the larger context has been elaborated by all authors for an advanced teaching of wall bounded flows.
Flow Field Investigation in Draft Tube of Francis Turbine at Off-Design Operation Using a Vortex Identification Algorithm
Authors: Kumar Sandeep , Khullar Subodh , Gandhi Bhupendra K.
Published: October 2021

At off-design operations, flow instabilities such as vortex breakdown, reverse flows, and stagnant regions are observed in Francis turbines. The present work shows the numerical flow field investigations of a Francis turbine at two different part loads (PL) by employing a vortex identification algorithm. The analysis has been performed at various locations in the draft tube by extracting the velocity fields at different time steps of the simulation. The first operating point involves a fully developed rotating vortex rope (RVR) in the draft tube, which precesses at a frequency of 0.28 times of the runner rotation. The present algorithm is able to identify the regions along with the eccentric local rotation center. The second operating regime shows characteristics of deep part load with central solid body rotation in the draft tube flow field. The results show highly swirling flows with very low axial velocity. The flow is confined primarily near the walls. The analysis shows that the extent of stagnation region at deep part load is more and no inner shear layer is present as compared to the part-load operation. The spatial harmonic decomposition (SHD) of the pressure data is also performed to evaluate the synchronous and asynchronous components of pressure pulsations.
Secondary Flow Loss Reduction Method by Use of Endwall Contouring in Gas Turbine Cascade Using Optimization Method
Authors: Yamamoto Kazuki , Uehara Ryota , Mizuguchi Shohei , Miyabe Masahiro
Published: October 2021

High efficiency is strongly demanded for gas turbines to reduce CO2 emissions. In order to improve the efficiency of gas turbines, the turbine inlet temperature is being raised higher. In that case, the turbine blade loading is higher and secondary flow loss becomes a major source of aerodynamic losses due to the interaction between the horseshoe vortex and the strong endwall cross flow. One of the authors have optimized a boundary layer fence which is a partial vane to prevent cross-flow from pressure-side to suction-side between blade to blade. However, it was also found that installing the fence leads to increase another loss due to tip vortex, wake and viscosity. Therefore, in this paper, we focused on the endwall contouring and the positive effect findings from the boundary layer fence were used to study its optimal shape. Firstly, the relationship between the location of the endwall contouring and the internal flow within the turbine cascade was investigated. Two patterns of contouring were made, one is only convex and another is just concave, and the secondary flow behavior of the turbine cascade was investigated respectively. Secondly, the shape was designed and the loss reduction effect was investigated by using optimization method. The optimized shape was manufactured by 3D-printer and experiment was conducted using cascade wind tunnel. The total pressure distributions were measured and compared with CFD results. Furthermore, flow near the endwall and the internal flow of the turbine cascade was experimentally visualized. The internal flow in the case of a flat wall (without contouring), with a fence, and with optimized endwall contouring were compared by experiment and CFD to extract the each feature.
A Versatile IBM-Based AMR Method for Studying Human Snoring
Authors: Zhang Wei , Pan Yu , Gong Yuchen , Dong Haibo , Xi Jinxiang
Published: October 2021

In this work, a local adaptive mesh refinement (AMR) embedded incompressible flow solver is developed for biomedical flows. This AMR technique is based on the block-structured mesh and adapted from an in-house numerical solver for the Navier-Stokes equations with immersed-boundary method embedded, which is suitable for flows with complex and moving boundaries in biomedical applications. Flow behavior of the human upper airway under various head-neck postures is evaluated using the developed AMR technique, where the head-neck posture is hypothesized to change the cross-sectional area of the airway, therefore the airflow and aerodynamic behavior. The anatomically accurate three-dimensional human upper airway model is reconstructed from human magnetic resonance images (MRI) with measurements from the literature. Analyses were performed on vortex dynamics and pressure fluctuations in the pharyngeal airway. It was found that the vortex formation and aerodynamic pressure were affected by the airway bending. The sniffing position or the head-neck junction extension posture tend to facilitate the airflow through the upper human airway.
Fractal and Convolutional Analysis for Deep Atmospheric Turbulence Using Machine Learning
Authors: Dudu Nicholas , Rodriguez Arturo , Moran Gael , Terrazas Jose , Adansi Richard , Kotteda V. M. Krushnarao , Harris Christopher , Kumar Vinod
Published: October 2021

Atmospheric turbulence studies indicate the presence of self-similar scaling structures over a range of scales from the inertial outer scale to the dissipative inner scale. A measure of this self-similar structure has been obtained by computing the fractal dimension of images visualizing the turbulence using the widely used box-counting method. If applied blindly, the box-counting method can lead to misleading results in which the edges of the scaling range, corresponding to the upper and lower length scales referred to above are incorporated in an incorrect way. Furthermore, certain structures arising in turbulent flows that are not self-similar can deliver spurious contributions to the box-counting dimension. An appropriately trained Convolutional Neural Network can take account of both the above features in an appropriate way, using as inputs more detailed information than just the number of boxes covering the putative fractal set. To give a particular example, how the shape of clusters of covering boxes covering the object changes with box size could be analyzed. We will create a data set of decaying isotropic turbulence scenarios for atmospheric turbulence using Large-Eddy Simulations (LES) and analyze characteristic structures arising from these. These could include contours of velocity magnitude, as well as of levels of a passive scalar introduced into the simulated flows. We will then identify features of the structures that can be used to train the networks to obtain the most appropriate fractal dimension describing the scaling range, even when this range is of limited extent, down to a minimum of one order of magnitude.
Investigation of Particle Size Effects on Solid Particle Erosion of Elbows in Series for Liquid-Solid Flows
Authors: Rajkumar Yeshwanthraj , Karimi Soroor , Shirazi Siamack A.
Published: October 2021

The entrainment of solid particles within the produced fluids can cause solid particle erosion by impacting the piping of production and transportation facilities. Liquid dominated flows are commonly encountered in deep water subsea pipelines while producing oil and gas fluids. It is of great importance to predict the erosion pattern and magnitude for elbows in series in liquid-solid flows as in the oil and gas productions, liquids tends to produce more solid particles compared to gas-solid flows. In the current work, erosion of elbows in series for different particle sizes are investigated by using computational fluid dynamics (CFD) and compare the erosion pattern results with the results of paint removal experiments using a 76.2 mm diameter acrylic elbows, qualitatively. CFD simulations have been performed to study the particle size effects on erosion using Reynolds stress turbulence model (RSM) and Low-Reynolds number K-ε model. Grid refinement studies have been performed and particles are rebounded at the particle radius to accurately examine the effects of particle sizes on solid particle erosion of these elbows. The CFD results shows that significant erosion is observed at the inner wall of the first elbow for larger particles, and the maximum erosion can be seen towards the end of the second elbow for 300 μm particle size.
A Comprehensive Review of 4D Flow MRI and CFD in Cardiovascular and Congenital Heart Disease
Authors: El Nihum Lamees , Chinnadurai Ponraj , Lin C. Huie , Banerjee Debjyoti
Published: October 2021

A growing population of adults with congenital heart disease (CHD) has spurred increased study in recent decades into the complex anatomical vasculature of congenital heart patients and the resulting hemodynamic changes that progressively affect the heart and great vessels. To this end, assessment of flow dynamics using advanced imaging technology and computational simulations have paved a path toward greater understanding of the patterns and implications of flow alterations in complex and changing vasculature, and offer promise for diagnostic and therapeutic intervention in the future. The focus of this review is to describe past studies of four-dimensional (4D) magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) in the literature as related to pathophysiology of the heart in structural and CHD. This review will highlight the importance of working with both imaging and simulation technology to co-validate experimental (4D MRI) and simulation (CFD) models, allowing for more accurate depiction of flow dynamics within human vasculature and ultimately toward improvement of the tools and methodologies used in analysis, simulation and prediction of cardiovascular hemodynamics toward enhanced diagnostics and therapeutic intervention.
Design, Microfabrication and Testing of Brain-on-a-Chip (BOC) Platform Using Neural Organoids (Spheroids)
Authors: Shettigar Nandan , El Nihum Lamees , Thyagarajan Ashok , Banerjee Debjyoti , Krencik Robert
Published: October 2021

Three-dimensional (3D) organoid engineering aims to steer cell aggregates toward physiological mimicking of human tissue and organ systems at the cellular level, essentially serving as tissue and organ proxies that recapitulate biological parameters (e.g., spatial organization of heterogenous tissue-specific cells, cell-cell interactions, etc.). Currently, attempts at generation of brain organoids do not mature beyond the prenatal brain equivalent, the major obstacle being the lack of vascularization in the initial embryoid bodies that ultimately limit the growth and maturation of the organoids. Thus, attention is turned toward generation of a brain-on-a-chip model that can serve as a relevant model of the human brain in its recapitulation of the neuronal circuit (i.e., organoid-on-chip or “OOC”; brain-on-chip or “BOC”). In this study, soft lithography techniques using polydimethylsiloxane (PDMS) elastomers were implemented to fabricate a microfluidic chip to serve as a BOC/OOC. A mold was fabricated using 3D printing for performing soft lithography of the BOC (followed by bonding on to a glass slide). Neural organoids (spheroids) were dispensed into the BOC using a pipette. The BOC was designed for the organoids to be captured at specific locations using micro-pillars that are located strategically within the microchannel network. Copper microelectrodes were manually inserted into the device through specially designed ports to serve as probes (as electrical sensors) and were mounted strategically for detection of electrical response from the organoids. Experiments were conducted to acquire and analyze the electrical response of the organoids when subjected to a variety of conditions (and stimuli). Two sets of organoids were tested in these experiments: organoids that are light responsive (LR) and organoids that are not light responsive (NLR). The set of experiments performed in this study include: control experiments using pure media (exposed to light), control experiments performed using media decanted from organoid suspensions (with and without exposure to light for both LR and NLR), baseline tests using organoids not exposed to light (control experiments for both LR and NLR), and experiments involving organoids exposed to variety of stimuli (light exposure, saline solution, etc. for both LR and NLR).
Reducing interaural tonotopic mismatch preserves binaural unmasking in cochlear implant simulations of single-sided deafness
Authors: Sagi Elad , Azadpour Mahan , Neukam Jonathan , Capach Nicole Hope , Svirsky Mario A.
Published: October 2021

Binaural unmasking, a key feature of normal binaural hearing, can refer to the improved intelligibility of masked speech by adding masking that facilitates perceived separation of target and masker. A question relevant for cochlear implant users with single-sided deafness (SSD-CI) is whether binaural unmasking can still be achieved if the additional masking is spectrally degraded and shifted. CIs restore some aspects of binaural hearing to these listeners, although binaural unmasking remains limited. Notably, these listeners may experience a mismatch between the frequency information perceived through the CI and that perceived by their normal hearing ear. Employing acoustic simulations of SSD-CI with normal hearing listeners, the present study confirms a previous simulation study that binaural unmasking is severely limited when interaural frequency mismatch between the input frequency range and simulated place of stimulation exceeds 1–2 mm. The present study also shows that binaural unmasking is largely retained when the input frequency range is adjusted to match simulated place of stimulation, even at the expense of removing low-frequency information. This result bears implications for the mechanisms driving the type of binaural unmasking of the present study and for mapping the frequency range of the CI speech processor in SSD-CI users.
Cross-frequency weights in normal and impaired hearing: Stimulus factors, stimulus dimensions, and associations with speech recognition
Authors: Roverud Elin , Dubno Judy R. , Richards Virginia M. , Kidd Gerald
Published: October 2021

Previous studies of level discrimination reported that listeners with high-frequency sensorineural hearing loss (SNHL) place greater weight on high frequencies than normal-hearing (NH) listeners. It is not clear whether these results are influenced by stimulus factors (e.g., group differences in presentation levels, cross-frequency discriminability of level differences used to measure weights) and whether such weights generalize to other tasks. Here, NH and SNHL weights were measured for level, duration, and frequency discrimination of two-tone complexes after measuring discriminability just-noticeable differences for each frequency and stimulus dimension. Stimuli were presented at equal sensation level (SL) or equal sound pressure level (SPL). Results showed that weights could change depending on which frequency contained the more discriminable level difference with uncontrolled cross-frequency discriminability. When cross-frequency discriminability was controlled, weights were consistent for level and duration discrimination, but not for frequency discrimination. Comparing equal SL and equal SPL weights indicated greater weight on the higher-level tone for level and duration discrimination. Weights were unrelated to improvements in recognition of low-pass-filtered speech with increasing cutoff frequency. These results suggest that cross-frequency weights and NH and SNHL weighting differences are influenced by stimulus factors and may not generalize to the use of speech cues in specific frequency regions.
Periodic acoustic pulse generation by mode locked thermoacoustic oscillator
Authors: Hirayama Y. , Biwa T. , Delage R.
Published: October 2021

This study documents periodic acoustic pulse generation by heat in a thermoacoustic oscillator system constructed from a gas-filled acoustic resonance tube having a porous medium called a stack. When the system's dissonancy was enhanced by a local cross-sectional area change in the resonance tube, the periodic pulsed state was turned to a quasiperiodic state. This observation suggests that the acoustic pulse was created through the mode-locking of internal oscillation modes. Propagation of pulsed acoustic intensity in the resonance tube was evidenced by simultaneous measurements of acoustic pressure and axial acoustic particle velocity of the gas.
Ankle Dorsiflexion Promotes Irradiation of Ipsilateral Quadriceps Musculature in a Healthy Population
Authors: Lahne Emily , Golden Grace , Linens Shelley W.
Published: October 2021

Clinical Question: Does ankle dorsiflexion promote irradiation of ipsilateral lower extremity musculature during a maximal isometric quadriceps contraction task in a healthy population? Clinical Bottom Line: There is preliminary evidence supporting the use of active ankle dorsiflexion during isometric quadriceps exercises to promote increased quadriceps activation and force production. As isometric quadriceps exercises are often included in initial stage rehabilitation, increasing muscle activation and force production may be beneficial.
Reprogrammable soft actuation and shape-shifting via tensile jamming
Authors: Yang Bilige , Baines Robert , Shah Dylan , Patiballa Sreekalyan , Thomas Eugene , Venkadesan Madhusudhan , Kramer-Bottiglio Rebecca
Published: October 2021

Rapidly tunable tensile stiffness enables localized shape adaptations in next-generation robotic materials.
A constraint on post–6 Ma timing of western Grand Canyon (Arizona, USA) incision removed: Local derivation indicated by ca. 5.4 Ma fluvial deposits below Shivwits Plateau basalts north of Grand Canyon
Authors: Steelquist A.T. , Hilley G.E. , Lucchitta I. , Young R.A.
Published: October 2021

The timing of integration of the Colorado River system is central to understanding the landscape evolution of much of the southwestern United States. However, the time at which the Colorado River started incising the westernmost Grand Canyon (Arizona) is still an unsettled question, with conflicting interpretations of both geologic and thermochronologic data from western Grand Canyon. Fluvial gravels on the Shivwits Plateau, north of the canyon, have been reported to contain clasts derived from south of the modern canyon, suggesting the absence of western Grand Canyon at the time of their deposition. In this study, we reassess these deposits using modern geochronologic measurements to determine the age of the deposits and the presence or absence of clasts from south of the Grand Canyon. We could not identify southerly derived clasts, so cannot rule out the existence of a major topographic barrier such as Grand Canyon prior to the age of deposition of the gravels. 40Ar/39Ar analysis of a basalt clast entrained in the upper deposit (in combination with prior data) supports a maximum age of deposition of ca. 5.4 Ma, limiting deposition to post-Miocene, a period from which very few diagnostic and dated fluvial deposits remain in the western Colorado Plateau. Analysis of detrital zircon composition of the sand matrix supports interpretation of the deposit as being locally derived and not part of a major throughgoing river. We suggest that the published constraint of <6 Ma timing of Grand Canyon incision may be removed, given that no clasts that must be sourced from south of Grand Canyon were found in the only known outcrop of gravels under the Shivwits Plateau basalts at Grassy Mountain north of Grand Canyon.
On Linear Instability of Atmospheric Quasi-hydrostatic Equations in Response to Small Shortwave Perturbations
Authors: Xu X. , Nigmatulin R. I.
Published: October 2021

A set of 3-dimensional atmospheric-dynamics equations with quasi-hydrostatic approximation is proposed and justified with the practical goal to optimize atmospheric modelling at scales ranging from meso meteorology to global climate. Sound waves are filtered by applying the quasi-hydrostatic approximation. In the closed system of hydro/thermodynamic equations, the inertial forces are negligibly small compared to gravity forces, and the asymptotically exact equation for vertical velocity is obtained. Investigation of the stability of solutions to this system in response to small shortwave perturbations has shown that solutions have the property of shortwave instability. There are situations when the increment of the perturbation amplitude tends to infinity, corresponding to absolute instability. It means that the Cauchy problem for such equations may be ill-posed. Its formulation can become conditionally correct if solutions are sought in a limited class of sufficiently smooth functions whose Fourier harmonics tend to zero reasonably quickly when the wavelengths of the perturbations approach zero. Thus, the numerical scheme for the quasi-hydrostatic equations using the finite-difference method requires an adequately selected pseudo-viscosity to eliminate the instability caused by perturbations with wavelengths of the order of the grid size. The result is useful for choosing appropriate vertical and horizontal grid sizes for modelling to avoid shortwave instability associated with the property of the system of equations. Implementation of pseudo-viscosities helps to smoothen or suppress the perturbations that occur during modelling.
Concomitant pulmonary embolism and upper limb ischaemia as a first presentation of a patent foramen ovale
Authors: Houtzager Tessa , Berg Ingvar , Urlings Thijs , Grauss Robert
Published: October 2021

A 78-year-old female patient presented to the emergency department with syncope and dyspnoea. The left arm appeared to be cold and radial pulse was not palpable. A CT scan of the chest and left arm with intravenous contrast displayed bilateral central pulmonary embolisms in combination with a left subclavian artery embolism and an atrial septal aneurysm. Transthoracic echocardiography identified a patent foramen ovale with right-to-left shunting confirming the diagnosis of paradoxical embolism. The patient was treated with anticoagulants. In a patient presenting with a combination of a pulmonary embolism and a peripheral arterial embolism, the clinician should consider a right-to-left shunt with paradoxical embolism. In line with this, when diagnosing a peripheral arterial embolism, a central venous origin should be considered. Furthermore, when diagnosing a pulmonary embolism or other forms of venous thromboembolism, the clinician should be aware of signs of a peripheral arterial embolism.
Hypereosinophilia: a rare cause of stroke and multiorgan dysfunction
Authors: Barbind Kapil L , Boddu Revanth , Shijith KP , Mishra Kundan
Published: October 2021

Eosinophilia can occur due to a plethora of allergic, infective, neoplastic and idiopathic conditions. Hypereosinophilic syndrome (HES) is characterised by sustained eosinophilia and multiorgan dysfunction in the absence of an identifiable cause. It may range from a self-limiting condition to a rapidly progressive life-threatening disorder, of which ischaemic stroke is a rare presentation. Such episodes can rarely be the presenting manifestation, and may develop before any other laboratory abnormality or organ involvement. We report a case of HES presented with multiorgan (neurological and renal) involvement, managed successfully with steroids and cytoreductive therapy. High initial absolute eosinophil count can be a clue to the diagnosis and early treatment should be initiated in such patients, to prevent fatal outcomes.
HIV transmission knowledge among Rohingya refugee women in Bangladesh: a cross-sectional survey
Authors: Khan Md Nuruzzaman , Rahman Md Mashiur , Rahman Md Mostafizur , Islam M Mofizul
Published: October 2021

Background and objective

Increasing numbers of Rohingya refugees have been found to be infected with HIV since they arrived in Bangladesh after being ousted from Myanmar in 2017. This study aimed to examine the knowledge about HIV transmission among Rohingya refugee women and to identify factors that are associated with that knowledge.

Design

A cross-sectional survey was conducted using a structured questionnaire that was based on the standard questionnaire of the Demographic and Health Survey programme.

Setting

Rohingya settlements in the Kutupalong refugee camp at Ukhiya, Cox’s Bazar, Bangladesh.

Participants

Interviews were conducted with 508 women who had married or given birth in the 2 years before the survey was done.

Outcome measure

The participants were asked to answer a set of questions to assess their knowledge about HIV transmission.

Results

Around 70% of the women could not accurately answer four of the eight questions, and there were substantial misconceptions about the modes of HIV transmission. Knowledge regarding HIV transmission among participants increases in conjunction with the age at which they were first married. Women who were involved in work outside their households or those whose husbands were employed were more likely than others to demonstrate relatively good knowledge of transmission. Women who had received some formal education were 2.37 times likely to show relatively good knowledge of HIV transmission than those who had not received any education. Availability of healthcare facilities in the blocks where women resided is also associated with better knowledge. However, knowledge of HIV transmission among Rohingya women was significantly lower than among women in Bangladesh and Myanmar.

Conclusion

Most Rohingya women have inadequate knowledge of HIV transmission. Targeted interventions are needed to provide HIV education and to assist with prevention and behavioural changes.
Changes in neonatal admissions, care processes and outcomes in England and Wales during the COVID-19 pandemic: a whole population cohort study
Authors: Greenbury Sam F , Longford Nicholas , Ougham Kayleigh , Angelini Elsa D , Battersby Cheryl , Uthaya Sabita , Modi Neena
Published: October 2021

Objectives

The COVID-19 pandemic instigated multiple societal and healthcare interventions with potential to affect perinatal practice. We evaluated population-level changes in preterm and full-term admissions to neonatal units, care processes and outcomes.

Design

Observational cohort study using the UK National Neonatal Research Database.

Setting

England and Wales.

Participants

Admissions to National Health Service neonatal units from 2012 to 2020.

Main outcome measures

Admissions by gestational age, ethnicity and Index of Multiple Deprivation, and key care processes and outcomes.

Methods

We calculated differences in numbers and rates between April and June 2020 (spring), the first 3 months of national lockdown (COVID-19 period), and December 2019–February 2020 (winter), prior to introduction of mitigation measures, and compared them with the corresponding differences in the previous 7 years. We considered the COVID-19 period highly unusual if the spring–winter difference was smaller or larger than all previous corresponding differences, and calculated the level of confidence in this conclusion.

Results

Marked fluctuations occurred in all measures over the 8 years with several highly unusual changes during the COVID-19 period. Total admissions fell, having risen over all previous years (COVID-19 difference: −1492; previous 7-year difference range: +100, +1617; p<0.001); full-term black admissions rose (+66; −64, +35; p<0.001) whereas Asian (−137; −14, +101; p<0.001) and white (−319; −235, +643: p<0.001) admissions fell. Transfers to higher and lower designation neonatal units increased (+129; −4, +88; p<0.001) and decreased (−47; −25, +12; p<0.001), respectively. Total preterm admissions decreased (−350; −26, +479; p<0.001). The fall in extremely preterm admissions was most marked in the two lowest socioeconomic quintiles.

Conclusions

Our findings indicate substantial changes occurred in care pathways and clinical thresholds, with disproportionate effects on black ethnic groups, during the immediate COVID-19 period, and raise the intriguing possibility that non-healthcare interventions may reduce extremely preterm births.
Codesigning a supportive online resource for Australian cancer carers: a thematic analysis of informal carers’ and healthcare professionals’ perspectives about carers’ responsibilities and content needs
Authors: Perera Sharnel Miriam , O’Callaghan Clare , Ugalde Anna , Santin Olinda , Beer Cassandra , Prue G , Lane Katherine , Hanna Gerard G , Schofield Penelope
Published: October 2021

Objective

To gather preliminary qualitative data that will assist in the codesign and development of a new informational and supportive website to assist informal cancer carers in Australia.

Design and setting

Utilising a previously tested codesign process, informal carers’ experiences and perspectives, including those of healthcare professionals’, were examined via focus groups and/or interviews. Data were analysed via thematic analysis.

Participants

Rural (n=9) and urban (n=11) carers’, and healthcare professionals’ (n=8) perspectives were collected. Carers participated in a focus group (n=9) or telephone interview (n=11). Healthcare professionals completed an interview (n=6) or online survey (n=2).

Results

Rural and urban carers typically felt ill prepared for their multitudinal caregiving responsibilities. Supporting patient-to-healthcare professional liaisons could especially challenge. Carers’ biopsychosocial and fiscal strains were affected by patients’ hardships and available informal supports. Rural carers described greater social support than urban carers. Both rural and urban carers also described discontentment related to a carer neglecting healthcare system. Both carers and healthcare professionals endorsed the need for a user-friendly, carer-specific website encompassing practical information and resources, peer-driven advice and evidence-based illness information, tailored to the Australian context.

Conclusions

Carers and healthcare professionals recognise the pressing need for an Australian, cancer carer-specific online resource. Findings will inform the next phase, where a resource will be designed, developed and tested.
wEight chanGes, caRdio-mEtabolic risks and morTality in patients with hyperthyroidism (EGRET): a protocol for a CPRD–HES linked cohort study
Authors: Torlinska Barbara , Hazlehurst Jonathan M , Nirantharakumar Krishnarajah , Thomas G Neil , Priestley Julia R , Finnikin Samuel J , Saunders Philip , Abrams Keith R , Boelaert Kristien
Published: October 2021

Introduction

Hyperthyroidism is a common condition affecting up to 3% of the UK population. Treatment improves symptoms and reduces the risk of atrial fibrillation and stroke that contribute to increased mortality. The most common symptom is weight loss, which is reversed during treatment. However, the weight regain may be excessive, contributing to increased risk of obesity. Current treatment options include antithyroid drugs, radioiodine and thyroidectomy. Whether there are differences in either weight change or the long-term cardiometabolic risk between the three treatments is unclear.

Methods and analysis

The study will establish the natural history of weight change in hyperthyroidism, investigate the risk of obesity and risks of cardiometabolic conditions and death relative to the treatment. The data on patients diagnosed with hyperthyroidism between 1 January 1996 and 31 December 2015 will come from Clinical Practice Research Datalink linked to Hospital Episode Statistics and Office of National Statistics Death Registry. The weight changes will be modelled using a flexible joint modelling, accounting for mortality. Obesity prevalence in the general population will be sourced from Health Survey for England and compared with the post-treatment prevalence of obesity in patients with hyperthyroidism. The incidence and time-to-event of major adverse cardiovascular events, other cardiometabolic outcomes and mortality will be compared between the treatments using the inverse propensity weighting model. Incidence rate ratios of outcomes will be modelled with Poisson regression. Time to event will be analysed using Cox proportional hazards model. A competing risks approach will be adopted to estimate comparative incidences to allow for the impact of mortality.

Ethics and dissemination

The study will bring new knowledge on the risk of developing obesity, cardiometabolic morbidity and mortality following treatment for hyperthyroidism to inform clinical practice and public health policies. The results will be disseminated via open-access peer-reviewed publications and directly to the patients and public groups (Independent Scientific Advisory Committee protocol approval #20_000185).
The Defence Medical Library Service and Military Medicine
Authors: Walker S. B.
Published: October 2021

The Defence Medical Library Service (DMLS) supports the clinical practice and career development of military health professionals across the world. Clinical governance and the need for medical knowledge to be evidence-based means the DMLS has a central role to play in support of defence medicine. The DMLS is important for enabling health professionals to make sense of the evidence-based pyramid and the hierarchy of medical knowledge. The Royal Centre for Defence Medicine (RCDM) in Birmingham is recognised as an international centre of excellence. The information, knowledge and research requirements of the RCDM will provide opportunities for the DMLS to support and engage with the academic community.
The Psychological Morbidity of Military Healthcare Workers
Authors: Burden James I. F. , Jeffery Samuel M. T. , Jonathan Leach A.
Published: October 2021

Objective

To measure the probable prevalence of psychological morbidity in military healthcare professionals using the General Health Questionnaire 28.

Results

21 (35%) of military healthcare workers showed psychological ill health. Royal Air Force health staff had a significantly higher prevalence of ill health than both the Army [12 (63%) vs 6 (23%)] and the Royal Navy [12 (63%) vs 1 (8%)]. RAF non-commissioned staff were found to have a highly significant prevalence of ill health compared to the Army non-commissioned staff [7(70%) vs 1 (7%)], and Royal Navy non-commissioned staff [7 (70%) vs 0 (0%)].

Conclusion

The study shows significant differences in psychological ill health between Services at the RCDM. Comparison with civilian data showed that the overall prevalence of psychological morbidity was no higher than in NHS staff. The elevated level of ill health in the Royal Air Force staff warrants further investigation and possible intervention.
Overview of 12 Months Anaesthetic Activity in a UK Field Hospital on Enduring Operations in Iraq
Authors: Bateman R. M. , McNicholas J. J. K.
Published: October 2021

The British Field Hospital facility in Southern Iraq has seen a continuous turnover of patient admissions since the start of offensive operations during the 2003 Gulf conflict (Operation TELIC). During the war a number of procedures were carried out and these have been well described to date1,2,3. On May 1st 2003 President Bush declared an end to high intensity operations with a subsequent reduction in medical activity. However, the facility has continued to provide medical care to large numbers of service and civilian patients from the end of hostilities to the present day. The purpose of this review is to present anaesthetic and demographic data relating to procedures carried out at the Field Hospital over a 12-month period from the end of the war-fighting phase of the conflict.
Vertebral Wedge Fracture after Speedboat ‘Splash Down’
Authors: Wild G.
Published: October 2021

A case is presented of a soldier with wedge fracture of T12 sustained after an axial compression (± flexion) injury in a Rigid-Hull Inflatable Boat (RIB). Very powerful boats, such as RIBs, are used on a daily basis in the Royal Navy (RN). Despite this, fractures of the spine are unusual (1). This study explores the mechanism of injury and illustrates that a wedge frature should be considered in anyone presenting with back pain after a ‘splash down’ injury.
Addicted to green: priming effect of menthol cigarette packaging on brain response to smoking cues
Authors: Shi Zhenhao , Wang An-Li , Fairchild Victoria P , Aronowitz Catherine A , Lynch Kevin G , Loughead James , Langleben Daniel D
Published: October 2021

Introduction

Mentholated tobacco cigarettes are believed to be more addictive than non-menthol ones. Packaging of most menthol cigarette brands includes distinctive green hues, which may act as conditioned stimuli (ie, cues) and promote menthol smoking. To examine the cue properties of menthol cigarette packaging, we used a priming paradigm to assess the effect of packaging on the neural substrates of smoking cue reactivity. We hypothesised that menthol packaging will exert a specific priming effect potentiating smoking cue reactivity in menthol compared with non-menthol smokers.

Methods

Forty-two menthol and 33 non-menthol smokers underwent functional MRI while viewing smoking and neutral cues. The cues were preceded (ie, primed) by briefly presented images of menthol or non-menthol cigarette packages. Participants reported craving for cigarettes in response to each cue.

Results

Menthol packaging induced greater frontostriatal and occipital smoking cue reactivity in menthol smokers than in non-menthol smokers. Menthol packaging also enhanced the mediation by neural activity of the relationship between cue exposure and cigarette craving in menthol but not non-menthol smokers. Dynamic causal modelling showed stronger frontostriatal-occipital connectivity in response to menthol packaging in menthol compared with non-menthol smokers. The effects of non-menthol packaging did not differ between categories of smokers.

Conclusions

Our findings demonstrate heightened motivational and perceptual salience of the green-hued menthol cigarette packaging that may exacerbate menthol smokers’ susceptibility to smoking cues. These effects could contribute to the greater addiction severity among menthol smokers and could be considered in the development of science-based regulation and legal review of tobacco product marketing practices.
Code Polymorphism Meets Code Encryption: Confidentiality and Side-channel Protection of Software Components
Authors: Morel Lionel , Couroussé Damien , Hiscock Thomas
Published: October 2021

In this article, we consider that, in practice, attack scenarios involving side-channel analysis combine two successive phases: an analysis phase, targeting the extraction of information about the target and the identification of possible vulnerabilities, and an exploitation phase, applying attack techniques on candidate vulnerabilities. We advocate that protections need to cover these two phases to be effective against real-life attacks. We present
PolEn
, a toolchain and a processor architecture that combine countermeasures to provide an effective mitigation of side-channel attacks: As a countermeasure against the analysis phase, our approach considers the use of code encryption; as a countermeasure against the exploitation phase, our approach considers the use of code polymorphism, because it relies on runtime code generation, and its combination with code encryption is particularly challenging. Code encryption is supported by a processor extension such that machine instructions are only decrypted inside the CPU, which effectively prevents reverse engineering or any extraction of useful information from memory dumps. Code polymorphism is implemented by software means. It regularly changes the observable behaviour of the program, making it unpredictable for an attacker, hence reducing the possibility to exploit side-channel leakages. We present a prototype implementation, based on the RISC-V Spike simulator and a modified LLVM toolchain. In our experimental evaluation, we illustrate that
PolEn
effectively reduces side-channel leakages. For the protected functions evaluated, static memory use increases by a factor of 5 to 22, corresponding to the joint application of code encryption and code polymorphism. The overhead, in terms of execution time, ranges between a factor of 1.8 and 4.6.
Recurrent Germline Mutations of CHEK2 as a New Susceptibility Gene in Patients with Pheochromocytomas and Paragangliomas
Authors: Gao Yinjie , Ling Chao , Ma Xiaosen , Wang Huiping , Cui Yunying , Nie Min , Tong Anli
Published: October 2021

Purpose. Recently, pheochromocytomas and paragangliomas (PPGLs) have been strongly suspected as hereditary tumors, as approximately 40% of patients carry germline mutations. In the cancers where defects occur to corrupt DNA repair and facilitate tumorigenesis, a CHEK2 strong association has been observed. Therefore, the purpose of this study was to investigate the effect of CHEK2 mutations for its possible pathogenicity in PPGLs. Methods. Four patients with CHEK2 mutations were recruited, as previously detected by the whole exome sequencing. Sanger sequencing was used to verify the germline mutations as well as the loss of heterozygosities (LOHs) in their somatic DNAs. Immunohistochemistry was used to analyze the expression of CHEK2 and its downstream target p53 Ser20 (phosphorylated p53). Results. The average age of studied patients was 44.25 ± 11.18 years, at the time diagnosis. One patient had multiple tumors which recurred quickly, while two patients had distant metastasis. None of the patient had any relevant family history. Four germline CHEK2 mutations were identified (c.246_260del; c.715G > A; c.1008+3A > T; and c.1111C > T). All the patients were predicted to have either pathogenic or suspected pathogenic mutations. There was no LOH of CHEK2 gene in somatic DNAs found. Additionally, neither CHEK2 proteins nor its downstream target p53 Ser20 were expressed in the tumor tissues. The inactivation of CHEK2 leads to the decrease in the p53 phosphorylation, which might promote tumorigenesis. Conclusions. For the first time, CHEK2 was identified as a susceptibility gene for PPGLs. However, the penetrance of CHEK2 gene with genotype-phenotype correlation needs to be investigated.
Girder Longitudinal Movement and Its Factors of Suspension Bridge under Vehicle Load
Authors: Huang Guoping , Hu Jianhua , Liu Haibo , Sun Xiugui
Published: October 2021

Vehicle load may not only cause vertical deformation and vibration of suspension bridge but also lead to longitudinal deformation and vibration. And the longitudinal behavior is closely related to the durability of the girder end devices and the bending fatigue failure of suspenders. In this study, the longitudinal deformation behavior and longitudinal vibration of suspension bridge under vehicles, as well as the related influencing factors, are investigated. The underlying mechanism of girder longitudinal movement under the moving vehicles is revealed. Based on the simplified vehicle model of vertical concentrated force, the characteristics of main cable deformation and girder longitudinal displacement under vertical loads are analyzed first. Then, the longitudinal motion equation of the girder under vertical moving loads is derived. Finally, a single long‐span suspension bridge is employed in the case study, and the girder longitudinal response and influencing factors are investigated based on both numerical simulation and field monitoring. Results indicate that the asymmetric vertical load leads to cable longitudinal deflection owing to the geometrically nonlinear characteristic of the main cable, leading to longitudinal movement of the girder. The results of field monitoring and numerical simulation indicate that the girder moves quasi‐statically and reciprocates longitudinally with centimeter amplitude under normal operational loads.
Site-Specific Volumetric Skeletal Changes in Women with a Distal Forearm Fracture
Authors: Wihlborg Axel , Bergström Karin , Bergström Ingrid , Gerdhem Paul
Published: October 2021

Purpose. To assess site-specific volumetric bone and muscle changes, as well as demographic and biochemical changes, in postmenopausal women with a low-energy distal forearm fracture. Methods. In a cross-sectional case-control study, postmenopausal women with a distal forearm fracture were compared with age- and gender-matched controls. In total, 203 postmenopausal women (104 cases and 99 controls), with a mean age of 65 years, were included. Measurements included peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) as well as blood sampling and questionnaires. Results. Forearm trabecular volumetric BMD and total BMD assessed with pQCT were significantly lower in fracture cases compared to controls (

p
<
0.001

). Significantly higher cross-sectional area, lower cortical BMD, and lower cortical thickness were seen in women with fracture (

p
<
0.033

,

p
<
0.001

, and

p
<
0.001

, respectively). Postmenopausal women with fracture had significantly lower hip and spine areal BMD assessed with DXA (

p
<
0.001

). Activity level was higher and a history of falling was more frequent in women with fracture (

p
<
0.019

and

p
<
0.001

, respectively). Vertebral fracture was observed in 24 women (22%) with a distal forearm fracture. Muscle area, muscle density, PTH, and 25OHD did not differ between fracture cases and controls. Conclusion. A distal forearm fracture was associated with site-specific and central bone changes. Postmenopausal women with fracture had a larger bone area in combination with a thinner cortex and lower site-specific total BMD. In addition, women with fracture had a higher activity level, an increased occurrence of previous fall accidents, and a high prevalence of vertebral fractures. Forearm muscle composition, PTH, and 25OHD were not associated with forearm fracture. Fracture preventive measures following a low-energy distal forearm fracture seem beneficial.