bluuebunny/crossref_metadata_2025 huggingface dataset:
Passive Vibration Control of the Head Actuator Assembly in Hard Disk Drive
Authors: Xu LiMei , Zeng Sheng , Guo NingQun , Lin Rongming
Published: November 2020

It is known that a quasi-rigid body mode exists in hard disk drives in the frequency range from 3 to 6 kHz and it is caused by the flexibility of the pivot, the mass and structure of the head actuator assembly. The mode hinders performance improvement of servo system in bandwidth. In this paper, a tuned damping device is proposed to suppress this mode. The damping device is to be installed on the arm and hollow space within the voice coil motor on the HDDs. The dynamic characteristics of the head actuator assembly with the tuned damping device are measured in both frequency domain and time domain. It is shown that the tuned damping device can work effectively to suppress the quasi-rigid body vibration of the head actuator assembly and minimize the residual vibration in head positioning.
Internal Resonance of the Jeffcott Rotor With Nonlinear Spring Characteristics
Authors: Ishida Yukio , Inoue Tsuyoshi
Published: November 2020

The Jeffcott rotor is a two-degree-of-freedom linear model with a disk at the midspan of a massless elastic shaft. This model executing lateral whirling motions has been widely used in the linear analyses of rotor vibrations. In the Jeffcott rotor, the natural frequency of a forward whirling mode pf and that of a backward whirling mode pb have the relation of internal resonance pf : pb = 1 : (−1). Recently, many researchers analyzed nonlinear phenomena by using the Jeffcott rotor with nonlinear elements. However, they did not take this internal resonance relationship into account. While, in many cases of the practical rotating machinery, such a relationship holds apprximately due to small gyroscopic moment.

In this paper, nonlinear phenomena in the vicinity of the major critical speed and the rotational speeds of twice and three times the major critical speed are investigated in the Jeffcott rotor and rotor systems with small gyroscopic moment. Especially, the influences of internal resonance on the nonlinear resonances are studied in detail. The following were clarified theoretically and experimentally: (a) the shape of resonance curves becomes far more complex than that of a single resonance, (b) almost-periodic motions occur, (c) these phenomena are influenced remarkably by the asymmetrical nonlinearity and gyroscopic moment, and (d) the internal resonance phenomena are strongly influenced by the degree of the discrepancies among critical speeds. The results teach us the usage of the Jeffcott rotor in nonlinear analyses of rotor systems may induce incrrect results.
Signal Based Methods to Extract A Priori Information for the Identification of Nonlinear Systems
Authors: Bruns Jens-Uwe , Popp Karl
Published: November 2020

The identification of nonlinear dynamical systems still is a non-trivial procedure. Signal based methods that retrieve basic information about the system prior to detailed identification can provide valuable assistance in this task. In the paper the detection and characterization of nonlinearities as well as the estimation of the system order are discussed. Regarding the first topic, a new method is presented that is based on the Method of Internal Harmonics Cross-Correlation by Dimentberg and Sokolov but provides additional information about the nature of the nonlinearity and uses nonlinear instead of linear correlation. Concerning the second topic, a method is presented that, in contrast to most existing methods for nonlinear systems, incorporates a random input signal to promote the excitation of all system states. Both methods are illustrated with numerical examples.
Nonlinear and Chaotic Snap-Through Response of Buckled Plates Under Sinusoidal Base Excitation
Authors: Ng C. F. , Poon W. Y. , Lee Y. Y.
Published: November 2020

A simple dynamic model of a general buckled plate using a single mode model is used to present the typical trend of nonlinear behavior. The nonlinear dynamic buckling of curved plate acted upon by a sinusoidal excitation and its effects on the overall dynamic response can be easily interpreted using the single-mode formula. The important non-linear dynamic characteristics of curved plates are found to be the transition from softening spring effects to hardening spring effects through the intermediate region of chaotic motion. The chaotic motion is an intermittent motion with large amplitude between the two static buckled positions of the plate. The theoretical predictions are in agreement with the experimental results. The experience from the studies can also be used to improve the testing and monitoring techniques for noise transmission and nonlinear vibration of curved plate under acoustic or airflow load.
Improved Estimations of Unstable Periodic Orbits Extracted From Chaotic Sets
Authors: Al-Zamel Z. , Feeny B. F.
Published: November 2020

Unstable periodic orbits of the saddle type are often extracted from chaotic sets. We use the recurrence method of extracting segments of the chaotic data to approximate the true unstable periodic orbit. Then nearby trajectories are then examined to obtain the dynamics local to the extracted orbit, in terms of an affine map. The affine map is then used to estimate the true orbit. Accuracy is evaluated in examples including well known maps and the Duffing oscillator.
Symmetry-Breaking and Chaos in Oscillatory Neural Networks
Authors: Chen Yonghong , Xu Jianxue , Fang Tong
Published: November 2020

Complex dynamical behavior of neural networks may lead to new methodology of information processing. In this paper the dynamics of a neural network designed by the normal form for Hopf bifurcation is studied. The secondary Hopf bifurcation of the network is discussed and a two-torus is observed. Examining the phase-locking motions on the two-torus, we present the conditions of symmetry-breaking occurring in the system. If the ratio of the two frequencies of the codimension two Hopf bifurcation is represented by an irreducible fraction, then the symmetry-breaking will occur when either the numerator or the denominator of the fraction is an even number. Chaotic attractors may be created with the sigmoid nonlinearities added to the right hand side of the normal form equations. The phase trajectory and the second order Poincaré maps of the chaotic attractor are given. The chaotic attractor looks like a butterfly on some of the second order Poincaré maps. This is a marvelous example for chaos to mimic nature.
Delayed Position-Feedback Controller for the Reduction of Payload Pendulations of Rotary Cranes
Authors: Nayfeh Ali H. , Masoud Ziyad N.
Published: November 2020

In this work, we show that in rotary cranes, it is possible to reduce payload pendulations significantly by controlling the translational and rotational degrees of freedom of the crane. Such a control can be achieved with the heavy equipment that is already part of the crane so that retrofitting existing cranes with such a controller would require a small effort. Moreover, the control is superimposed on the commands of the operator transparently. The successful control strategy is based on delayed-position feedback of the payload motion in-plane and out-of-plane of the crane. Its effectiveness is demonstrated with a fully nonlinear three-dimensional computer simulation and with an experiment on a scaled model of a rotary crane. The results demonstrate that the pendulations can be significantly reduced, and therefore the operations rate can be greatly increased. The effectiveness of the controller is demonstrated for both rotary and gantry modes of operation of the crane.
Stochastic Car Vibrations With Strong Nonlinearities
Authors: Wedig Walter V. , von Wagner Utz
Published: November 2020

High dimensional probability density functions of nonlinear dynamical systems are calculated by solutions of Fokker-Planck equations. First approximations are derived via the solutions of the associated linear system and the analytical results of the expected values. These first approximations are utilized as weighting functions for the construction of generalized orthogonal polynomials. The Fokker-Planck equation is expanded into these polynomials and solved by a Galerkin method.

As an example, a simple model of a quarter car with nonlinear damping subjected to white or coloured noise excitation is considered. The damping characteristic is piecewisely linear and highly non-symmetrical. The excitation is generated by the roughness of the road surface on which the car is driving with constant velocity. The main result is a non-vanishing mean value of the vertical car vibrations. Monte-Carlo simulations and analytical results are applied for comparison and tests.
Dynamic Analysis of Unsymmetrical Flexible Rotor-Bearing Foundation System Under an Unsteady Oil-Film Force
Authors: Liu Zhansheng , Huang Senlin , Su Jiexian , Huang Wenhu
Published: November 2020

Based on an unsymmetrical rotor model, the dynamic analysis of an unsymmetrical flexible rotor-bearing-foundation system supported by short journal bearing is presented, considering anisotropy of foundation stiffness and asymmetry of rotor stiffness. A more reasonable nonlinear unsteady oil-film force model, which is determined only by three functions, is adopted in the paper and the explicit analytical formula of oil-film force for short journal bearing is used. Using the Runge-Kutta method, the influence of parameters on the unsymmetrical flexible rotor-bearing-foundation system is investigated. Numerical results show that instability of system may be improved by decreasing the asymmetry of rotor stiffness and increasing the stiffness of foundation.
Fault Tolerant Control of Magnetic Bearings
Authors: Na Uhn Joo , Provenza Andrew , Palazzolo Alan B. , Choi Benjamin , Montague Gerald , Kascak Albert
Published: November 2020

This paper provides a new algorithm and test verification for implementing fault-tolerant operation of magnetically suspended, flexible shaft, rotating machinery. The currents to the magnetic bearing are redistributed in a manner so that the bearing actuator preserves the same linearized magnetic forces after some of its coils experience failure. The algorithm that searches a database for the appropriate failure compensation matrix utilizes a Boolean description of the failure state to quickly locate and download its target. The test results are shown to have good agreement with the system simulation results presented.
Non-Smooth Variational Problems in Mechanics
Authors: Bajkowski Jerzy , Grzesikiewicz Wiesław , Oslński Zbigniew
Published: November 2020

We consider a variational problem in which the minimized functional is convex but non-differentiable. In the static case, the variational problem serves to describe the mechanical system’s equilibrium position. In the rheological case it is employed to determine the velocities, and in the dynamical case it can be used to determine the accelerations of the body.
Theory, Experiments and Numerical Simulations of Instantaneous Collisions of Solids
Authors: Dimnet Eric
Published: November 2020

We describe the collision of a point with a fixed plane and the simultaneous collisions of a collection of rigid bodies following the theory of collisions by M. Frémond. We then give some existence and uniqueness results for simultaneous collisions of a collection of rigid bodies, and we show some numerical simulations of the evolutions of collections of solids during which such collisions happen. We also modelize instantaneous collisions of deformable bodies. Then, considering the impact of a hammer with a deformable bar, we show the agreement between measurements and our modeling.
Achilles Tendon Length Is Not Related to 100-m Sprint Time in Sprinters
Authors: Tomita Daichi , Suga Tadashi , Ueno Hiromasa , Miyake Yuto , Tanaka Takahiro , Terada Masafumi , Otsuka Mitsuo , Nagano Akinori , Isaka Tadao
Published: November 2020

This study examined the relationship between Achilles tendon (AT) length and 100-m sprint time in sprinters. The AT lengths at 3 different portions of the triceps surae muscle in 48 well-trained sprinters were measured using magnetic resonance imaging. The 3 AT lengths were calculated as the distance from the calcaneal tuberosity to the muscle–tendon junction of the soleus, gastrocnemius medialis, and gastrocnemius lateralis, respectively. The absolute 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = −.023 to .064, all Ps > .05). Furthermore, to minimize the differences in the leg length among participants, the 3 AT lengths were normalized to the shank length, and the relative 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = .023 to .102, all Ps > .05). Additionally, no significant correlations were observed between the absolute and relative (normalized to body mass) cross-sectional areas of the AT and personal best 100-m sprint time (r = .012 and .084, respectively, both Ps > .05). These findings suggest that the AT morphological variables, including the length, may not be related to superior 100-m sprint time in sprinters.
In PDAC, “bad” cholesterol is good
Authors: Ferrarelli Leslie K.
Published: November 2020

LDL-lowering statins can promote the development of an aggressive subtype of pancreatic cancer.
Vibrio fischeri Amidase Activity Is Required for Normal Cell Division, Motility, and Symbiotic Competence
Authors: Fidopiastis Pat M. , Mariscal Vanessa , McPherson Jeanne-Marie , McAnulty Sarah , Dunn Anne , Stabb Eric V. , Visick Karen L.
Published: November 2020

Peptidoglycan (PG) is a critical microbe-associated molecular pattern (MAMP) that is sloughed by cells of
V. fischeri
during symbiotic colonization of squid. Specifically, this process induces significant remodeling of a specialized symbiotic light organ within the squid mantle cavity.
Mixtures of Insect-Pathogenic Viruses in a Single Virion: towards the Development of Custom-Designed Insecticides
Authors: Beperet Inés , Simón Oihane , López-Ferber Miguel , van Lent Jan , Williams Trevor , Caballero Primitivo
Published: November 2020

Alphabaculoviruses are used as biological insecticides and expression vectors in biotechnology and medical applications. We demonstrate that in caterpillars infected with particular mixtures of viruses, the genomes of different baculovirus species can be enveloped together within individual virions and occluded within proteinaceous occlusion bodies.
GenSeizer: a Multiplex PCR-Based Targeted Gene Sequencing Platform for Rapid and Accurate Identification of Major
Mycobacterium
Species
Authors: Li Bing , Xu Liyun , Guo Qi , Chen Jianhui , Zhang Yanan , Huang Wenpan , Zhang Zhemin , Han Lizhong , Xu Xiaogang , Chu Haiqing
Published: November 2020

Mycobacterium tuberculosis
and nontuberculous mycobacterium (NTM) infections often exhibit similar clinical symptoms. Timely and effective treatment relies on the rapid and accurate identification of species and resistance genotypes.
A Replication-Defective Influenza Virus Harboring H5 and H7 Hemagglutinins Provides Protection against H5N1 and H7N9 Infection in Mice
Authors: Tian Xingui , Landreth Shelby , Lu Yao , Pandey Kannupriya , Zhou Yan
Published: November 2020

Avian influenza H5N1 and H7N9 viruses infected humans with high mortality rates. A highly safe and effective vaccine is needed to protect against a potential pandemic.
Draft Genome Sequence of Pseudomonas aeruginosa Strain PA14-UM
Authors: Lee Vincent T. , Ghodssi Reza , El-Sayed Najib M. , Malik Rena D. , Goloubeva Olga G. , Hazen Tracy H. , Rasko David A.
Published: November 2020

Pseudomonas aeruginosa
is a Gram-negative nosocomial pathogen that is a leading cause of morbidity and mortality in cystic fibrosis patients and immunocompromised individuals worldwide. The isolate examined in this study, PA14-UM, is a well-characterized isolate utilized in studies from the University of Maryland.
Genome Sequence of Eubacterium callanderi AMC0717, Isolated from the Colonic Mucosa of an 11-Year-Old Organ Donor
Authors: Marsh Alan J. , Chandrashekhar Kshipra , Ng Sandy , Roach Jeff , Magness Scott T. , Azcarate-Peril M. Andrea
Published: November 2020

Eubacterium callanderi
AMC0717 was isolated from the mucosa of the transverse colon of an 11-year-old organ donor. This strain contains genes putatively encoding short-chain fatty acids (SCFAs), exopolysaccharide (EPS), and several B vitamins.
Rapid implementation of Microsoft Teams in response to COVID-19: one acute healthcare organisation’s experience
Authors: Mehta Jay , Yates Timothy , Smith Penelope , Henderson Daisy , Winteringham Glenn , Burns Aine
Published: November 2020

BackgroundCOVID-19 presented significant challenges to healthcare organisations, which needed to rapidly remodel their services but were unable to allow staff to meet face to face to minimise infection risk. During this communication predicament, National Health Service (NHS) Digital announced the provision of Microsoft Teams, a digital communication and collaboration tool, which was implemented at Royal Free London NHS Foundation Trust within 2 weeks.

MethodGiven the need to deploy at scale, rapidly and with minimal resource, an agile decentralised innovation management approach was used, empowering staff to be local implementors.

ResultsResulting use cases were highly original and varied, ranging from a COVID-19 Education Programme to coordination of oxygen demand. Analytics showed rapid and persistent adoption, surpassing 500 daily active users within 11 days. Usage continues to increase, consistent with a direct network effect.

ConclusionThese findings suggest a high demand for this format of communication and high willingness to adopt it. Further qualitative research into staff perceptions would be valuable to confirm this, and to assess the user experience.

Overall, this has been a radical approach to digital implementation in healthcare, and has so far proved effective in delivering a cost minimal, rapid communication tool at scale in the midst of a global pandemic.
Modification of diet, exercise and lifestyle (MODEL) study: a randomised controlled trial protocol
Authors: Radavelli-Bagatini Simone , Bondonno Catherine P , Sim Marc , Blekkenhorst Lauren C , Anokye Reindolf , Connolly Emma , Bondonno Nicola P , Schousboe John T , Woodman Richard J , Zhu Kun , Szulc Pawel , Jackson Ben , Dimmock James , Schlaich Markus P , Cox Kay L , Kiel Douglas P , Lim Wai H , Stanley Mandy , Devine Amanda , Thompson Peter L , Gianoudis Jenny , De Ross Belinda , Daly Robin M , Lewis Joshua R , Hodgson Jonathan M
Published: November 2020

Introduction

Most cardiovascular disease (CVD)-related events could be prevented or substantially delayed with improved diet and lifestyle. Providing information on structural vascular disease may improve CVD risk factor management, but its impact on lifestyle change remains unclear. This study aims to determine whether providing visualisation and pictorial representation of structural vascular disease (abdominal aortic calcification (AAC)) can result in healthful diet and lifestyle change.

Methods and analysis

This study, including men and women aged 60–80 years, is a 12-week, two-arm, multisite randomised controlled trial. At baseline, all participants will have AAC assessed from a lateral spine image captured using a bone densitometer. Participants will then be randomised to receive their AAC results at baseline (intervention group) or a usual care control group that will receive their results at 12 weeks. All participants will receive information about routinely assessed CVD risk factors and standardised (video) diet and lifestyle advice with three simple goals: (1) increase fruit and vegetable (FV) intake by at least one serve per day, (2) improve other aspects of the diet and (3) reduce sitting time and increase physical activity. Clinical assessments will be performed at baseline and 12 weeks.

Outcomes

The primary outcome is a change in serum carotenoid concentrations as an objective measure of FV intake. The study design, procedures and treatment of data will adhere to Standard Protocol Items for Randomized Trials guidelines.

Ethics and dissemination

Ethics approval for this study has been granted by the Edith Cowan University and the Deakin University Human Research Ethics Committees (Project Numbers: 20513 HODGSON and 2019-220, respectively). Results of this study will be published in peer-reviewed academic journals and presented in scientific meetings and conferences. Information regarding consent, confidentiality, access to data, ancillary and post-trial care and dissemination policy has been disclosed in the participant information form.

Trial registration number

Australian New Zealand Clinical Trial Registry (ACTRN12618001087246).
Effectiveness of deep electroacupuncture with strong deqi and shallow electroacupuncture with no deqi for lumbar disk herniation: study protocol for a randomised controlled trial
Authors: Huang Ziling , Zhao Jianxin , Pei Xinghong , Wang Bobo
Published: November 2020

Introduction

Lumbar disk herniation (LDH) is a common cause of low back pain and dysfunction. Studies have shown that electroacupuncture (EA) can achieve pain relief in patients with LDH. However, there is a lack of evidence regarding the effectiveness of deep EA with strong deqi and shallow EA with no deqi in patients with LDH. This study aims to evaluate the effectiveness of deep EA with strong deqi and shallow EA with no deqi in the treatment of LDH.

Methods and analysis

In this randomised controlled trial, patients with LDH who have low back pain with or without radiculopathy for at least 12 weeks will be enrolled. In total, 44 patients will be recruited from the Third Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China. Patients will be randomised into the deep EA group and the shallow EA group in a ratio of 1:1 and will be administered 12 sessions of EA treatment (three times a week for 4 weeks, 20 min for each session). The follow-up duration will be 4 weeks. Low back pain intensity and leg pain intensity (in patients with radicular pain) measured using the Visual Analogue Scale (VAS) will be assessed as the primary outcomes. Function (measured using the Roland-Morris Disability Questionnaire), quality of life (measured using the EuroQol Five-Dimensional Five-Level Questionnaire) and patient-evaluated therapeutic effect will be assessed as the secondary outcomes. Patients’ expectations of EA, the success of the blinding method and safety will also be evaluated. Statistical analyses will be followed by the intention-to-treat analysis.

Ethics and dissemination

This study was approved by the Ethics Committee of the Third Affiliated Hospital of Beijing University of Chinese Medicine (approval number: 2019-XS-ZB06). Study results will be disseminated through publication in an open access journal.

Trial registration number

ChiCTR-1900026518.
Discontinuing antidepressant medication after mindfulness-based cognitive therapy: a mixed-methods study exploring predictors and outcomes of different discontinuation trajectories, and its facilitators and barriers
Authors: Huijbers Marloes J , Wentink Carolien , Simons Esther , Spijker Jan , Speckens Anne
Published: November 2020

Objectives

This study aimed to explore predictors and outcomes associated with different trajectories of discontinuing antidepressant medication (ADM), in recurrently depressed individuals after participation in mindfulness-based cognitive therapy (MBCT). Facilitators and barriers of discontinuation were explored qualitatively.

Design

Mixed-methods study combining quantitative and qualitative data, drawn from a randomised controlled trial.

Setting

Twelve secondary and tertiary psychiatric outpatient clinics in the Netherlands.

Participants

Recurrently depressed individuals (N=226) who had been using ADM for at least 6 months and in partial or full remission. Regardless of trial condition, we made post-hoc classifications of patients’ actual discontinuation trajectories: full discontinuation (n=82), partial discontinuation (n=34) and no discontinuation (n=110) of ADM within 6 months after baseline. A subset of patients (n=15) and physicians (n=7) were interviewed to examine facilitators and barriers of discontinuation.

Interventions

All participants were offered MBCT, which consisted of eight weekly sessions in a group.

Primary and secondary outcome measures

Demographic and clinical predictors of successful discontinuation within 6 months, relapse risk within 15 months associated with different discontinuation trajectories, and barriers and facilitators of discontinuation.

Results

Of the 128 patients assigned to MBCT with discontinuation, only 68 (53%) fully discontinued ADM within 6 months, and 17 (13%) discontinued partially. Predictors of full discontinuation were female sex, being employed and lower levels of depression. Relapse risk was lower after no discontinuation (45%) or partial discontinuation (38%), compared with full discontinuation (66%) (p=0.02). Facilitators and barriers of discontinuation were clustered within five themes: (1) pre-existing beliefs about depression, medication and tapering; (2) current experience with ADM; (3) life circumstances; (4) clinical support and (5) mindfulness.

Conclusions

Discontinuing antidepressants appears to be difficult, stressing the need to support patients and physicians in this process. MBCT may offer one of these forms of support.

Trial registration number

ClinicalTrials.gov Registry (NCT00928980); post-results.
Assessing the benefits on quality of life of a multicomponent intervention for fibromyalgia syndrome in primary care: patients’ and health professionals’ appraisals: a qualitative study protocol
Authors: Arfuch Victoria Mailen , Caballol Angelats Rosa , Aguilar Martín Carina , Carrasco-Querol Noèlia , Sancho Sol Maria Cinta , González Serra Gemma , Fusté Anguera Immaculada , Gonçalves Alessandra Queiroga , Berenguera Anna
Published: November 2020

Introduction

Fibromyalgia syndrome (FMS) is a complex condition still scarcely understood and with ambiguity when prescribing treatment. Both patients and healthcare providers can supply valuable information for the development of new treatment strategies. The qualitative narrative analysis of participant’s accounts is potentially helpful to reveal new insights about their opinions, needs, and experiences and, consequently, to model healthcare interventions accurately. International treatment guidelines suggest a promising future for multicomponent intervention (MI) approaches for FMS. This study aims to assess the benefits of a MI for patients with FMS in the context of primary care (PC) inTerres de L’Ebre,Catalonia (Spain). Furthermore, it is intended to detect the overall perception of effectiveness and to understand patients’ lived experience and its impact on the quality of life.

Method and analysis

Qualitative research from a socioconstructivism paradigm perspective and a Hermeneutic Phenomenological method. For data collection, four focus group discussions (FGDs) of 8–12 people (2 FGDs of patients and 2 of professionals) and 10–12 key informant interviews with the participants in the MI group will be carried out. All the information will be recorded and verbatim transcribed to perform an interpretive thematic analysis.

Ethics and dissemination

This study protocol has been approved by the Clinical Research Ethics Committee from the IDIAPJGol Institute, on 25 April 2018 (code P18/068), according to the Declaration of Helsinki/Tokyo. All participants will receive oral/written information about the study, and they will be required to sign an informed consent sheet. Data anonymity will be guaranteed. Dissemination will be carried out through publications in scientific journals, presentations in academic meetings, workshops and through the local and national media.

Trial registration number

ClinicalTrials.gov:NCT04049006; Pre-results.
Understanding the underlying drivers of obesity in Africa: a scoping review protocol
Authors: Jaca Anelisa , Iwu Chinwe , Durão Solange , Onyango Adelheid W , Wiysonge Charles Shey
Published: November 2020

Introduction

The worldwide prevalence of obesity and overweight has doubled since 1980, such that approximately a third of the world’s population is reported as obese or overweight. Obesity rates have increased in all ages and both sexes irrespective of geographical area, ethnicity or socioeconomic status. Due to the high prevalence, related health consequences and costs of childhood and adult obesity, there is a need to comprehensively identify and assess the major underlying drivers of obesity and overweight in the African context.

Methods and analysis

This scoping review will be carried out as per the methodological outline by Arksey and O’Malley. The search strategy will be developed and search performed in the Scopus and PubMed electronic databases. In the first search, we will identify concepts that are used as an equivalent to obesity and overweight. Subsequently, we will search for studies comprising of search terms on the underlying factors that drive the development of obesity and overweight. Lastly, we will check reference lists for additional publications. Abstracts and full-text studies will independently be screened by two authors.

Ethics and dissemination

The proposed study will generate evidence from published data and hence does not require ethics approval. Evidence generated from this review will be disseminated through journal publications and conference presentations.
Awake prone positioning of hypoxaemic patients with COVID-19: protocol for a randomised controlled open-label superiority meta-trial
Authors: Tavernier Elsa , McNicholas Bairbre , Pavlov Ivan , Roca Oriol , Perez Yonatan , Laffey John , Mirza Sara , Cosgrave David , Vines David , Frat Jean-Pierre , Ehrmann Stephan , Li Jie
Published: November 2020

Introduction

Prone positioning (PP) is an effective first-line intervention to treat patients with moderate to severe acute respiratory distress syndrome (ARDS) receiving invasive mechanical ventilation, as it improves gas exchanges and reduces mortality. The use of PP in awake spontaneous breathing patients with ARDS secondary to COVID-19 was reported to improve oxygenation in few retrospective trials with small sample size. High-level evidence of awake PP for hypoxaemic patients with COVID-19 patients is still lacking.

Methods and analysis

The protocol of this meta-trial is a prospective collaborative individual participant data meta-analysis of randomised controlled open label superiority trials. This design is particularly adapted to a rapid scientific response in the pandemic setting. It will take place in multiple sites, among others in USA, Canada, Ireland, France and Spain. Patients will be followed up for 28 days. Patients will be randomised to receive whether awake PP and nasal high flow therapy or standard medical treatment and nasal high flow therapy. Primary outcome is defined as the occurrence rate of tracheal intubation or death up to day 28. An interim analysis plan has been set up on aggregated data from the participating research groups.

Ethics and dissemination

Ethics approvals were obtained in all participating countries. Results of the meta-trial will be submitted for publication in a peer-reviewed journal. Each randomised controlled trial was registered individually, as follows: NCT04325906, NCT04347941, NCT04358939, NCT04395144 and NCT04391140.
Factors associated with COVID-19 infections and mortality in Africa: a cross-sectional study using publicly available data
Authors: Okeahalam Charles , Williams Victor , Otwombe Kennedy
Published: November 2020

Introduction

The current COVID-19 pandemic is a global threat. This elicits questions on the level of preparedness and capacity of health systems to respond to emergencies relative to other parts of the world.

Methods

This cross-sectional study uses publicly available core health data for 53 African countries to determine risk factors for cumulative COVID-19 deaths and cases per million in all countries in the continent. Descriptive statistics were determined for the indicators, and a negative binomial regression was used for modelling the risk factors.

Results

In sub-Saharan Africa, an increase in the number of nursing and midwifery personnel decreased the risk of COVID-19 deaths (p=0.0178), while a unit increase in universal healthcare (UHC) index of service coverage and prevalence of insufficient physical activity among adults increased the risk of COVID-19 deaths (p=0.0432 and p=0.0127). An increase in the proportion of infants initiating breast feeding reduced the number of cases per million (p<0.0001), while an increase in higher healthy life expectancy at birth increased the number of cases per million (p=0.0340).

Conclusion

Despite its limited resources, Africa’s preparedness and response to the COVID-19 pandemic can be improved by identifying and addressing specific gaps in the funding of health services delivery. These gaps impact negatively on service delivery in Africa, which requires more nursing personnel and increased UHC coverage to mitigate the effects of COVID-19.
Parental perceptions of the impact of neonatal unit visitation policies during COVID-19 pandemic
Authors: Muniraman Hemananda , Ali Mahmoud , Cawley Paul , Hillyer Jessica , Heathcote Adam , Ponnusamy Vennila , Coleman Zoe , Hammonds Kendall , Raiyani Chandni , Gait-Carr Eleanor , Myers Sarah , Hunt Katie , Govande Vinayak , Jain Anoo , Clark Reese , Doherty Cora , Raju Venkata , Clarke Paul
Published: November 2020

Objectives

To ascertain parental perceptions of the impact of restricted visiting policies to neonatal intensive care units during the current COVID-19 pandemic.

Design

Cross-sectional survey of parents impacted by visitation policies.

Setting

Six tertiary level neonatal units, four from the UK and two from the USA, participated in the study.

Participants

Parents and families of infants hospitalised in the participating centres between 1 May 2020 and 21 August 2020.

Methods

Online-based and/or paper-based survey, querying the visitation policies and their impact on parents’ ability to visit, care for and bond with their infants.

Results

A total of 231 responses were received. Visitation limited to a single visitor with no restrictions on duration was the most frequently reported policy; 140/217 (63%). Visitation policies were perceived as being restrictive by 62% (138/219) of the respondents with 37% (80/216) reporting being able to visit less often than desired, 41% (78/191) reporting being unable to bond enough and 27% (51/191) reporting not being able to participate in their baby’s daily care. Mild to severe impact on breast feeding was reported by 36% (75/209) of respondents. Stricter policies had a higher impact on families and were significantly associated with a lack of bonding time, inability to participate in care and an adverse impact on breast feeding.

Conclusions

Visitation policies during the COVID-19 pandemic varied between centres and over time with stricter restrictions implemented earlier on in the pandemic. Parents reported significant impacts on their ability to visit, care for and bond with their infants with perceived severity of impact worse with stricter restrictions.
Nutrition and physical activity: French intergroup clinical practice guidelines for diagnosis, treatment and follow-up (SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, AFC, SFP-APA, SFNCM, AFSOS)
Authors: Neuzillet Cindy , Anota Amélie , Foucaut Aude-Marie , Védie Anne-Laure , Antoun Sami , Barnoud Didier , Bouleuc Carole , Chorin Frédéric , Cottet Vanessa , Fontaine Eric , Garabige Valérie , Hébuterne Xavier , Huguet Florence , Lièvre Astrid , Marchal Timothée , Mouillot Thomas , Peschaud Frédérique , Quilliot Didier , Raynard Bruno , Schneider Stéphane , Scotté Florian , Vansteene Damien , Mariani Pascale , Bouché Olivier , Joly Francisca ,   Société Nationale Française de Gastroentérologie (SNFGE),   Fédération Francophone de Cancérologie Digestive (FFCD),   Groupe Coopérateur multidisciplinaire en Oncologie (GERCOR),   Fédération Nationale des Centres de Lutte Contre le Cancer (UNICANCER),   Société Française de Chirurgie Digestive (SFCD),   Société Française d’Endoscopie Digestive (SFED),   Société Française de Radiothérapie Oncologique (SFRO),   Association de Chirurgie Hépato-Bilio-Pancréatique et Transplantation (ACHBT),   Association Française de Chirurgie (AFC),   Société Française des Professionnels en Activité Physique Adaptée (SFP-APA),   Société Francophone de Nutrition Clinique et Métabolisme (SFNCM)
Published: November 2020

This document is a summary of the French intergroup guidelines regarding the nutrition and physical activity (PA) management in digestive oncology. This collaborative work was produced under the auspices of all French medical and surgical societies involved in digestive oncology, nutrition and supportive care. It is based on published guidelines, recent literature review and expert opinions. Recommendations are graded according to the level of evidence. Malnutrition affects more than half of patients with digestive cancers and is often underdiagnosed. It has multiple negative consequences on survival, quality of life and risk of treatment complications. Consequently, in addition to anticancer treatments, supportive care including nutritional support and PA plays a central role in the management of digestive cancers. It is crucial to detect malnutrition (diagnostic criteria updated in 2019) early, to prevent it and to act against it at all stages of the cancer and at all times of the care pathway. In this context, we proposed recommendations for the evaluation and management in nutrition and PA in digestive oncology for each stage of the disease (perioperative setting, during radiation therapy, during systemic treatments, at the palliative phase, after cancer). Guidelines for nutrition and PA management aim at increasing awareness about malnutrition in oncology. They are continuously evolving and need to be regularly updated.
What is the normal composition of pericardial fluid?
Authors: Buoro Sabrina , Tombetti Enrico , Ceriotti Ferruccio , Simon Caterina , Cugola Diego , Seghezzi Michela , Innocente Francesco , Maestroni Silvia , del Carmen Baigorria Vaca Maria , Moioli Valentina , Previtali Giulia , Manenti Barbara , Adler Yehuda , Imazio Massimo , Brucato Antonio
Published: November 2020

Objective

Biochemical and cytological pericardial fluid (PF) analysis is essentially based on the knowledge of pleural fluid composition. The aim of the present study is to identify reference intervals (RIs) for PF according to state-of-art methodological standards.

Methods

We prospectively collected and analysed the PF and venous blood of consecutive subjects undergoing elective open-heart surgery from July 2017 to October 2018. Exclusion criteria for study enrolment were evidence of pericardial diseases at preoperatory workup or at intraoperatory assessment, or any other condition that could affect PF analysis.

Results

The final study sample included 120 patients (median age 69 years, 83 men, 69.1%). The main findings were (1) High levels of proteins, albumin and lactate dehydrogenase (LDH), but not of glucose and cholesterol (2) High cellularity, mainly represented by mesothelial cells. RIs for pericardial biochemistry were: protein content 1.7–4.6 g/dL PF/serum protein ratio 0.29–0.83, albumin 1.19–3.06 g/dL, pericardium-to-serum albumin gradient 0.18–2.37 g/dL, LDH 141–2613 U/L, PF/serum LDH ratio 0.40–2.99, glucose 80–134 mg/dL, total cholesterol 12–69 mg/dL, PF/serum cholesterol ratio 0.07–0.51. RIs for pericardial cells by optic microscopy were: 278–5608 × 106 nucleated cells/L, 40–3790 × 106 mesothelial cells/L, 35–2210 × 106 leucocytes/L, 19–1634 × 106 lymphocytes/L.

Conclusions

PF is rich in nucleated cells, protein, albumin, LDH, at levels consistent with inflammatory exudates in other biological fluids. Physicians should stop to interpret PF as exudate or transudate according to tools not validated for this setting.
Possible cardioprotective role of NaHS on ECG and oxidative stress markers in an unpredictable chronic mild stress model in rats
Authors: Ghalwash Mohammad , Elmasry Ahlam , Omar Nisreen Mansour Abo-elmaaty
Published: November 2020

The protective effect of H2S against various body organ injuries has been described. The aim of this work is to investigate the potential role of sodium hydrosulfide (NaHS) as an H2S donor in chronic mild stress induced changes in the rat heart. Forty adult male Sprague Dawley rats were assigned to four groups: control, stressed group, stressed rats treated with aminooxyacetic acid (AOAA), and stressed rats treated with NaHS. Arterial blood pressure (ABP) was recorded. Serum adrenaline, MDA, and GSH levels were measured. Chronic stress significantly increased HR and ABP. AOAA produced similar changes, while NaHS mitigated the rise in HR and ABP. Both stressed and AOAA-treated stressed groups showed a significant decrease in QRS amplitude and a shortening of the RR, QT, and QTc intervals with an elevation of the ST segment. NaHS produced a significant improvement in ECG recordings. Chronic stress produced a significant rise of adrenaline and MDA levels with a significant decline in GSH levels. The AOAA-treated stressed group showed similar elevations. NaHS treatment caused significant reduction in adrenaline and MDA levels but significantly improved GSH levels. In conclusion, H2S donor has a cardioprotective effect against stress-induced cardiovascular diseases through amelioration of the oxidative stress and raised adrenaline levels induced by chronic stress exposure.
Exchange proteins directly activated by cAMP mediate cardiac repolarization and arrhythmogenesis during chronic heart failure
Authors: Zhu Didi , Zhu Rui , Zhou Xiaozhu , Shi Erdan , Zhang Xinwei , Zhou Zihao , Li Dongcheng , Zou Jiangang , Wang Yao
Published: November 2020

Most sudden cardiac death in chronic heart failure (CHF) is caused by malignant ventricular arrhythmia (VA); however, the molecular mechanism remains unclear. This study aims to explore the effect of exchange proteins directly activated by cAMP (Epac) on VA in CHF and the potential molecular mechanism. Transaortic constriction was performed to prepare CHF guinea pigs. Epac activation model was obtained with 8-pCPT administration. Programmed electrical stimulation (PES) was performed to detect effective refractory period (ERP) or induce VA. Isolated adult cardiomyocytes were treated with 8-pCPT and (or) the Epac inhibitor. Cellular electrophysiology was examined by whole-cell patch clamp. With Epac activation, corrected QT duration was lengthened by 12.6%. The 8-pCPT increased action potential duration (APD) (APD50: 236.9 ± 18.07 ms vs. 328.8 ± 11.27 ms, p < 0.05; APD90: 264.6 ± 18.22 ms vs. 388.6 ± 6.47 ms, p < 0.05) and decreased rapid delayed rectifier potassium (IKr) current (tail current density: 1.1 ± 0.08 pA/pF vs. 0.7 ± 0.03 pA/pF, p < 0.05). PES induced more malignant arrhythmias in the 8-pCPT group than in the control group (3/4 vs. 0/8, p < 0.05). The selective Epac1 inhibitor CE3F4 rescued the drop in IKr after 8-pCPT stimulation (tail current density: 0.5 ± 0.02 pA/pF vs. 0.6 ± 0.03 pA/pF, p < 0.05). In conclusion, Epac1 regulates IKr, APD, and ERP in guinea pigs, which could contribute to the proarrhythmic effect of Epac1 in CHF.
Seed treatment of canola (Brassica napus) with the endomycorrhizal fungus Piriformospora indica does not reduce clubroot
Authors: Sedaghatkish Afsaneh , Gossen Bruce D. , McDonald Mary Ruth
Published: November 2020

A Basidiomycota endomycorrhizal fungus, Piriformospora indica Verma, colonizes and promotes the growth of canola (Brassica napus L.) and other Brassica crops and can reduce diseases of other crops. Clubroot is an important disease of Brassica crops caused by the obligate, soil-borne pathogen Plasmodiophora brassicae Woronin. The effect of P. indica on clubroot severity in canola was assessed in replicated growth room studies. Seed was treated with P. indica using a proprietary process. Microscopic observation confirmed that canola roots grown from treated seed were colonized by P. indica; however, P. indica did not consistently reduce clubroot severity and did not promote the growth of canola.
The effect of bulk dimension in the presence of string cloud on viscosity bound
Authors: Sadeghi Mehdi
Published: November 2020

In this paper, the Einstein AdS black brane solution in the presence of a string cloud in the context of d-dimensional massive gravity is introduced. The ratio of shear viscosity to entropy density for this solution violates the KSS bound by applying the Dirichlet boundary and regularity on the horizon conditions. Our result shows that this value is independent of string cloud in any arbitrary dimensions.
1907–2020: more than one century of colonic mass movements in humans
Authors: Bassotti Gabrio
Published: November 2020

Motility of the large bowel may be grossly subdivided in two types of contractile activity: low-amplitude single or cyclic propagated waves and high-amplitude propagated activity. The latter is mainly apt to shift relatively large amounts of colonic contents, and it is related to defecation. The main component of this propagated activity is represented by the radiologically identified mass movements that have a manometric equivalent known as high-amplitude propagated contractions (HAPC). The present article reviews origins and characterization of HAPC in the time course of colonic motility investigations, and correlates it with technological advancements in recent years, putting into perspective the future possible options to better detect and investigate these important physiological events.
Antipsychotic Drugs Reverse MK801-Inhibited Cell Migration and F-actin Condensation by Modulating the Rho Signaling Pathway in B35 Cells
Authors: Chen Yi-Chyan , Tsai Fu-Ming , Chen Mao-Liang
Published: November 2020

Background and Aim. MK801-induced psychotic symptoms and also the Ras homolog family member A (RhoA) expression and cell division control protein 42 (cdc42) mRNA modulation in the rat brain have been investigated. Antipsychotic drugs (APDs) have been reported to induce Rho GDP-dissociation inhibitor (RhoGDI) pathway regulation related to cytoskeleton reorganization in neuronal cells. It will be necessary to clarify the effects of APDs on MK801-induced RhoGDI signaling regulation in neuronal cells. Methods. B35 neuronal cells were treated with MK801 for 7 days then treated with MK801 in combination with haloperidol or clozapine for a further 7 days. Cell migration, F-actin condensation, and RhoGDI signaling regulation were examined to investigate the regulatory effects of MK801, haloperidol, and clozapine in B35 neuronal cells. Results. MK801 reduced B35 cell migration, whereas both haloperidol and clozapine reversed the reduction in cell migration induced by MK801. Haloperidol and clozapine restored F-actin condensation after it was diminished by MK801 in B35 cell nuclei. MK801 increased the RhoGDI1 and RhoA expression, which was diminished by the addition of haloperidol and clozapine. MK801 reduced the CDC42 expression, which was restored by haloperidol and clozapine. MK801 reduced the Rho-associated coiled-coil containing protein kinase 1 (ROCK1), profilin1 (PFN1), and neuronal Wiskott–Aldrich Syndrome protein (N-WASP) expression, which was further reduced by haloperidol and clozapine. MK801 also increased the phosphorylated myosin light chain 2 (p-MLC2), postsynaptic density protein 95 (PSD-95), and c-jun expression, which was decreased by haloperidol and clozapine. p21 (RAC1-) activated kinase 1 (PAK1) expression was not affected by MK801.