bluuebunny/crossref_metadata_2025 huggingface dataset:
Study protocol for a randomised controlled trial of enhanced informed consent compared to standard informed consent to improve patient understanding of early phase oncology clinical trials (CONSENT)
Authors: Pal Abhijit , Stapleton Sarah , Yap Christina , Lai-Kwon Julia , Daly Robert , Magkos Dimitrios , Baikady Bindumalini Rao , Minchom Anna , Banerji Udai , De Bono Johann , Karikios Deme , Boyle Frances , Lopez Juanita
Published: September 2021

Introduction

Early phase cancer clinical trials have become increasingly complicated in terms of patient selection and trial procedures—this is reflected in the increasing length of participant information sheets (PIS). Informed consent for early phase clinical trials has been contentious due to the potential ethical issues associated with performing experimental research on a terminally ill population which has exhausted standard treatment options. Empirical studies have demonstrated significant gaps in patient understanding regarding the nature and intent of these trials. This study aims to test whether enhanced informed consent for patient education can improve patient scores on a validated questionnaire testing clinical trial comprehension.

Methods and analysis

This is a randomised controlled trial that will allocate patients who are eligible to participate in one of four investigator-initiated clinical trials at the Royal Marsden Drug Development Unit to either a standard arm or an experimental arm, stratified by age and educational level. The standard arm will involve the full length trial PIS, followed by electronic or paper administration of the Quality of Informed Consent Questionnaire Parts A and B (QuIC-A and QuIC-B). The experimental arm will involve the full length trial PIS, exposure to a two-page study aid and 10 online educational videos, followed by administration of the QuIC-A and QuIC-B. The primary endpoint will be the difference (using a one-sided two-sample t-test) in the QuIC-A score, which measures objective understanding, between the standard and experimental arm. Accrual target is at least 17 patients per arm to detect an 8 point difference (80% power, alpha 0.05).

Ethics and dissemination

Ethics approval was granted by the National Health Service Health Research Authority on 15 June 2020—IRAS Project ID 277065, Protocol Number CCR5165, REC Reference 20/EE/0155. Results will be disseminated via publication in a relevant journal.

Trial registration number

NCT04407676; Pre-results.
Cost-effectiveness analysis of different screening strategies for colorectal cancer in Guangzhou, southern China: a Markov simulation analysis based on natural community screening results
Authors: Zhou Qin , Li Hai-lin , Li Yan , Gu Yu-ting , Liang Ying-ru , Liu Hua-zhang , Li Ke , Dong Hang , Chen Yuan-yuan , Lin Guo-zhen
Published: September 2021

Objectives

To evaluate the cost-effectiveness of four different primary screening strategies: high-risk factor questionnaire (HRFQ) alone, single immunochemical faecal occult blood test (iFOBT), double iFOBT and HRFQ+double iFOBT for colorectal cancer (CRC) screening compared with no screening using the Markov model.

Methods

Treeage Pro V.2011 software was used to simulate the Markov model. The incremental cost-effectiveness ratio, which was compared with the willingness-to-pay (WTP) threshold, was used to reflect the cost-effectiveness of the CRC screening method. One-way sensitivity analysis and probabilistic sensitivity analysis were used for parameter uncertainty.

Results

All strategies had greater effectiveness because they had more quality-adjusted life years (QALYs) than no screening. When the WTP was ¥435 762/QALY, all screening strategies were cost-effective compared with no screening. The double iFOBT strategy was the best-buy option compared with all other strategies because it had the most QALYs and the least cost. One-way sensitivity analysis showed that the sensitivity of low-risk adenoma, compliance with colonoscopy and primary screening cost were the main influencing factors comparing single iFOBT, double iFOBT and HRFQ+double iFOBT with no screening. However, within the scope of this study, there was no fundamental impact on cost-effectiveness. Probabilistic sensitivity analysis showed that when the WTP was ¥435 762/QALY, the probabilities of the cost-effectiveness acceptability curve with HRFQ alone, single iFOBT, double iFOBT and HRFQ+double iFOBT were 0.0%, 5.3%, 69.3% and 25.4%, respectively.

Conclusions

All screening strategies for CRC were cost-effective compared with no screening strategy. Double iFOBT was the best-buy option compared with all other strategies. The significant influencing factors were the sensitivity of low-risk polyps, compliance with colonoscopy and cost of primary screening.
Which strategy for using medical and community masks? A prospective analysis of their environmental impact
Authors: Bouchet Alexandre , Boucher Julien , Schutzbach Kevin , Senn Nicolas , Genton Blaise , Vernez David
Published: September 2021

Introduction

The use of personal protective equipment, especially medical masks, increased dramatically during the COVID-19 crisis. Medical masks are made of synthetic materials, mainly polypropylene, and a majority of them are produced in China and imported to the European market. The urgency of the need has so far prevailed over environmental considerations.

Objective

Assess the environmental impact of different strategies for the use of face mask.

Method

A prospective analysis was conducted to assess the environmental impact of different strategies for the use of medical and community masks. Eight scenarios, differentiating the typologies of masks and the modes of reuse are compared using three environmental impact indicators: the Global Warming Potential (GWP100), the ecological scarcity (UBP method, from German ‘Umweltbelastungpunkte’) and the plastic leakage (PL). This study attempts to provide clear recommendations that consider both the environmental impact and the protective effectiveness of face masks used in the community.

Results

The environmental impact of single-use masks is the most unfavourable, with a GWP of 0.4–1.3 kg CO2eq., depending on the transport scenario, and a PL of 1.8 g, for a 1 month protection against COVID-19. The use of home-made cotton masks and prolonged use of medical masks through wait-and-reuse are the scenarios with the lowest impact.

Conclusion

The use of medical masks with a wait and reuse strategy seems to be the most appropriate when considering both environmental impact and effectiveness. Our results also highlight the need to develop procedures and the legal/operational framework to extend the use of protective equipment during a pandemic.
Risk of harm in synthetic and biological intervention trials in patients with inflammatory arthritis: protocol for a metaepidemiological study focusing on contextual factors
Authors: Malm Esben , Nielsen Sabrina Mai , Berg Johannes , Ioannidis John P. A. , Furst Daniel , Smolen Josef S. , Taylor Peter C. , Kristensen Lars Erik , Tarp Simon , Ellingsen Torkell , Christensen Robin
Published: September 2021

Introduction

Inflammatory arthritis (IA) conditions, including rheumatoid arthritis, psoriatic arthritis and axial spondyloarthritis, are characterised by inflammatory infiltration of the joints. Biological disease-modifying antirheumatic drugs (bDMARDs) and targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs), respectively, reduce the effects of proinflammatory cytokines and immune cells to ameliorate disease. However, immunosuppression can be associated with high rates of serious adverse events (SAEs), including serious infections, and maybe an increased risk of malignancies and cardiovascular events. Currently, there is no empirical evidence on the extent to which contextual factors and risk of bias (RoB) domains may modify these harm signals in randomised trials.

Methods and analysis

We will search MEDLINE (via PubMed) for systematic reviews published since April 2015 and all Cochrane reviews. From these reviews, randomised trials will be eligible if they include patients with an IA condition with at least one group randomly allocated to bDMARD and/or tsDMARD treatments. A predefined form will be used for extracting data on population characteristics (eg, baseline characteristics or eligibility criteria, such as medication background) and specific harm outcome measures, such as number of withdrawals, numbers of patients discontinuing due to adverse events and number of patients having SAEs. RoB in individual trials will be assessed using a modified Cochrane RoB tool. We will estimate the potentially causal harm effects related to the experimental intervention compared with control comparator as risk ratios, and heterogeneity across randomised comparisons will be assessed statistically and evaluated as inconsistency using the I2Index. Our metaregression analyses will designate population and trial characteristics and each RoB domain as independent variables, whereas the three harm domains will serve as dependent variables.

Ethics and dissemination

Ethics approval is not required for this study. Results will be disseminated through publication in international peer-reviewed journals.

PROSPERO registration number

CRD42020171124.
Relapse prevention group therapy via video-conferencing for substance use disorder: protocol for a multicentre randomised controlled trial in Indonesia
Authors: Yamada Chika , Siste Kristiana , Hanafi Enjeline , Ophinni Youdiil , Beatrice Evania , Rafelia Vania , Alison Peter , Limawan Albert , Shinozaki Tomohiro , Matsumoto Toshihiko , Sakamoto Ryota
Published: September 2021

Background

Substance use disorder (SUD) is a leading contributor to the global burden of disease. In Indonesia, the availability of formal treatment for SUD falls short of the targeted coverage. A standardised therapeutic option for SUD with potential for widespread implementation is required, yet evidence-based data in the country are scarce. In this study, we developed a cognitive behavioural therapy (CBT)-based group telemedicine model and will investigate effectiveness and implementability in a multicentre randomised controlled trial.

Methods

A total of 220 participants will be recruited from the social networks of eight sites in Indonesia: three hospitals, two primary healthcare centres and three rehabilitation centres. The intervention arm will participate in a relapse prevention programme called the Indonesia Drug Addiction Relapse Prevention Programme (Indo-DARPP), a newly developed 12-week module based on CBT and motivational interviewing constructed in the Indonesian context. The programme will be delivered by a healthcare provider and a peer counsellor in a group therapy setting via video-conferencing, as a supplement to participants’ usual treatments. The control arm will continue treatment as usual. The primary outcome will be the percentage increase in days of abstinence from the primarily used substance in the past 28 days. Secondary outcomes will include addiction severity, quality of life, motivation to change, psychiatric symptoms, cognitive function, coping, and internalised stigma. Assessments will be performed at baseline (week 0), post-treatment (week 13), and 3 and 12 months post-treatment completion (weeks 24 and 60). Retention, participant satisfaction, and cost-effectiveness will be assessed as the implementation outcomes.

Ethics and dissemination

The study protocol was reviewed and approved by the Ethics Committees of Universitas Indonesia and Kyoto University. The results will be disseminated via academic journals and international conferences. Depending on trial outcomes, the treatment programme will be advocated for adoption as a formal healthcare-based approach for SUD.

Trial registration number

UMIN000042186.
Non-communicable diseases, sociodemographic vulnerability and the risk of mortality in hospitalised children and adolescents with COVID-19 in Brazil: a cross-sectional observational study
Authors: Sousa Braian Lucas Aguiar , Brentani Alexandra , Costa Ribeiro Cecilia Claudia , Dolhnikoff Marisa , Grisi Sandra Josefina Ferraz Ellero , Ferrer Ana Paula Scoleze , Ferraro Alexandre Archanjo
Published: September 2021

Objectives

To analyse how previous comorbidities, ethnicity, regionality and socioeconomic development are associated with COVID-19 mortality in hospitalised children and adolescents.

Design

Cross-sectional observational study using publicly available data from the Brazilian Ministry of Health.

Setting

Nationwide.

Participants

5857 patients younger than 20 years old, all of them hospitalised with laboratory-confirmed COVID-19, from 1 January 2020 to 7 December 2020.

Main outcome measure

We used multilevel mixed-effects generalised linear models to study in-hospital mortality, stratifying the analysis by age, region of the country, presence of non-communicable diseases, ethnicity and socioeconomic development.

Results

Individually, most of the included comorbidities were risk factors for mortality. Notably, asthma was a protective factor (OR 0.4, 95% CI 0.24 to 0.67). Having more than one comorbidity increased almost tenfold the odds of death (OR 9.67, 95% CI 6.89 to 13.57). Compared with white children, Indigenous, Pardo (mixed) and East Asian had significantly higher odds of mortality (OR 5.83, 95% CI 2.43 to 14.02; OR 1.93, 95% CI 1.48 to 2.51; OR 2.98, 95% CI 1.02 to 8.71, respectively). We also found a regional influence (higher mortality in the North—OR 3.4, 95% CI 2.48 to 4.65) and a socioeconomic association (lower mortality among children from more socioeconomically developed municipalities—OR 0.26, 95% CI 0.17 to 0.38)

Conclusions

Besides the association with comorbidities, we found ethnic, regional and socioeconomic factors shaping the mortality of children hospitalised with COVID-19 in Brazil. Our findings identify risk groups among children that should be prioritised for public health measures, such as vaccination.
Role of Dutch internal policy advisors in a hospital quality improvement programme and their influence on nurses’ role development: a qualitative study
Authors: van Schothorst - van Roekel Jannine , Weggelaar - Jansen Anne Marie J W M , Hilders Carina C G J M , Wallenburg Iris , de Bont Antoinette
Published: September 2021

Objective

Nurses are vital in providing and improving quality of care. To enhance the quality improvement (QI) competencies of nurses, hospitals in the Netherlands run developmental programmes generally led by internal policy advisors (IPAs). In this study, we identify the roles IPAs play during these programmes to enhance the development of nurses’ QI competencies and studied how these roles influenced nurses and management.

Design

An exploratory ethnographical study comprising observations, informal conversations, semistructured interviews, focus groups and a strategy evaluation meeting.

Setting

A teaching hospital in an urban region in the Netherlands.

Participants

IPAs (n=7) in collaboration with four teams of nurses (n=131), team managers (n=4), senior managers (n=4) and the hospital director (n=1).

Results

We identified five distinct advisory roles that IPAs perform in the hospital programme: gatekeeper, connector, converter, reflector and implementer. In describing these roles, we provide insights into how IPAs help nurses to develop QI competencies. The IPA’s professional background was a driving force for nurses’ QI role development. However, QI development was threatened if IPAs lost sight of different stakeholders’ interests and consequently lost their credibility. QI role development among nurses was also threatened if the IPA took on all responsibility instead of delegating it timely to managers and nurses.

Conclusions

We have shown how IPAs’ professional background and advisory knowledge connect organisational, managerial and professional aims and interests to enhance professionalisation of nurses.
Prevalence, awareness, treatment and control of hypertension among Ngawa Tibetans in China: a cross-sectional study
Authors: Li Tingxin , Shuai Ping , Wang Jinghong , Wang Lin
Published: September 2021

Objectives

To explore the prevalence, awareness, treatment and control rate of hypertension and analyse the potential social environment factors among Ngawa Tibetans in China.

Design

This was a cross-sectional observational study.

Setting

The investigation based on a multistage stratified cluster sampling was conducted in the Ngawa area, Sichuan Province, Southwest China. Tibetan residents were selected by random sampling method from one city and six counties in Ngawa.

Methods

Basic demographical information, physical activity and blood pressure were collected. In addition, the participants completed the questionnaire. A multivariate logistic regression analysis was used to examine the association between the prevalence, awareness, treatment and control rate of hypertension and the potential risk factors.

Participants

The sample comprised 2228 Ngawa Tibetan residents (age 18–80 years) from September 2018 to June 2019.

Results

The prevalence rate of hypertension was 24.6%. The control rate was 6.2%, while the awareness rate (32.3%) and treatment rate (21.7%) of hypertension had been significantly improved.

Conclusion

The prevalence of hypertension among Ngawa Tibetans was high. The awareness and treatment were improved in recent years. But the control rate was low. The government needs to strengthen the basic medical care and health education for Ngawa Tibetans.
Young people’s perceptions of accessing a community pharmacy for a chlamydia testing kit: a qualitative study based in North East England
Authors: Ahmaro Lara , Lindsey Laura , Forrest Simon , Whittlesea Cate
Published: September 2021

Objectives

Chlamydia testing among young people in community pharmacies in North East England has been low compared with other remote settings offering testing for the past few years. To understand why this may be, to maximise service provision, the perceptions of young men and women about pharmacy testing and possible chlamydia treatment were gathered and interpreted.

Design

Indepth, semistructured interviews.

Setting

Four youth centres in North East England.

Participants

The study included 26 young people aged 16–23. The sample of participants comprised those with a history of chlamydia testing as well as those never tested.

Interviews

Face-to-face interviews were conducted between October 2018 and May 2019. The interview schedule covered young people’s perceptions of sexually transmitted infections, provision of pharmacy sexual and reproductive health and chlamydia testing, and potential chlamydia treatment. Data from the interviews were subjected to thematic analysis.

Results

The geographical accessibility and long opening times of community pharmacies in North East England were perceived benefits of the service. However, young people had concerns about being judged by pharmacy staff or overheard by customers when requesting the test. Men did not want to be seen by their peers accessing the pharmacy. These barriers were associated with a perceived stigma of chlamydia. Despite this, young people thought that pharmacist advice on the test kit would be important to ensure they complete it correctly. Those never tested favoured how the kit could be taken home to complete the urine sample. The option of including chlamydia treatment was reported to be convenient and comforting.

Conclusion

Supporting pharmacies in North East England to offer a confidential chlamydia testing service is necessary to overcome young people’s perceived barriers to testing. Delivering testing as an integrated sexual health package with other pharmacy services, together with treatment where suitable, will increase acceptance for testing and timely access to treatment.
Deprescribing intervention activities mapped to guiding principles for use in general practice: a scoping review
Authors: Coe Amy , Kaylor-Hughes Catherine , Fletcher Susan , Murray Elizabeth , Gunn Jane
Published: September 2021

Objective

To identify and characterise activities for deprescribing used in general practice and to map the identified activities to pioneering principles of deprescribing.

Setting

Primary care.

Data sources

Medline, EMBASE (Ovid), CINAHL, Australian New Zealand Clinical Trials Registry (ANZCTR), Clinicaltrials.gov, ISRCTN registry, OpenGrey,Annals of Family Medicine, BMC Family Practice, Family PracticeandBritish Journal of General Practice(BJGP) from inception to the end of June 2021.

Study selection

Included studies were original research (randomised controlled trial, quasi-experimental, cohort study, qualitative and case studies), protocol papers and protocol registrations.

Data extraction

Screening and data extraction was completed by one reviewer; 10% of the studies were independently reviewed by a second reviewer. Coding of full-text articles in NVivo was conducted and mapped to five deprescribing principles.

Results

Fifty studies were included. The most frequently used activities were identification of appropriate patients for deprescribing (76%), patient education (50%), general practitioners (GP) education (48%), and development and use of a tapering schedule (38%). Six activities did not align with the five deprescribing principles. As such, two principles (engage practice staff in education and appropriate identification of patients, and provide feedback to staff about deprescribing occurrences within the practice) were added.

Conclusion

Activities and guiding principles for deprescribing should be paired together to provide an accessible and comprehensive guide to deprescribing by GPs. The addition of two principles suggests that practice staff and practice management teams may play an instrumental role in sustaining deprescribing processes within clinical practice. Future research is required to determine the most of effective activities to use within each principle and by whom.
Qualitative study of UK health professionals’ experiences of working at the point of care during the COVID-19 pandemic
Authors: Baldwin Sharin , George Joicy
Published: September 2021

Objectives

To develop an understanding of health professionals’ experiences of working at the point of care during the COVID-19 pandemic, the impact on their health and well-being and their support needs.

Design

A qualitative study using semistructured interviews. Data were analysed using framework analysis.

Setting

One large National Health Service integrated care trust.

Participants

A purposive sample of 19 qualified health professionals (doctors, nurses or allied health professionals), working with patients with COVID-19 admitted to the hospitals between March and May 2020 were eligible to take part.

Results

Eight major categories were identified: (1) Working in a ‘war zone’, (2) ‘Going into a war zone without a weapon’, (3) ‘Patients come first’, (4) Impact of COVID-19, (5) Leadership and management, (6) Support systems, (7) Health professionals’ support needs, and (8) Camaraderie and pride. Health professionals reported increased levels of stress, anxiety and a lack of sleep. They prioritised their patients’ needs over their own and felt a professional obligation to be at work. A key finding was the reported camaraderie among the health professionals where they felt that they were ‘fighting this war together’.

Conclusions

This study provides a valuable insight into the experiences of some of the frontline health professionals working in a large London-based hospital trust during the first COVID-19 peak. Findings from this study could be used to inform how managers, leaders and organisations can better support their health professional staff during the current pandemic and beyond.
GDF15 induces immunosuppression via CD48 on regulatory T cells in hepatocellular carcinoma
Authors: Wang Zhaowei , He Lei , Li Weina , Xu Chuanyang , Zhang Jieyu , Wang Desheng , Dou Kefeng , Zhuang Ran , Jin Boquan , Zhang Wei , Hao Qiang , Zhang Kuo , Zhang Wangqian , Wang Shuning , Gao Yuan , Gu Jintao , Shang Lei , Tan Zhijun , Su Haichuan , Zhang Yingqi , Zhang Cun , Li Meng
Published: September 2021

Background

A better understanding of the molecular mechanisms that manifest in the immunosuppressive tumor microenvironment (TME) is crucial for developing more efficacious immunotherapies for hepatocellular carcinoma (HCC), which has a poor response to current immunotherapies. Regulatory T (Treg) cells are key mediators of HCC-associated immunosuppression. We investigated the selective mechanism exploited by HCC that lead to Treg cells expansion and to find more efficacious immunotherapies.

Methods

We used matched tumor tissues and blood samples from 150 patients with HCC to identify key factors of Treg cells expansion. We used mass cytometry (CyTOF) and orthotopic cancer mouse models to analyze overall immunological changes after growth differentiation factor 15 (GDF15) gene ablation in HCC. We used flow cytometry, coimmunoprecipitation, RNA sequencing, mass spectrum, chromatin immunoprecipitation and Gdf15–/–, OT-I and GFP transgenic mice to demonstrate the effects of GDF15 on Treg cells and related molecular mechanism. We used hybridoma technology to generate monoclonal antibody to block GDF15 and evaluate its effects on HCC-associated immunosuppression.

Results

GDF15 is positively associated with the elevation of Treg cell frequencies in patients wih HCC. Gene ablation of GDF15 in HCC can convert an immunosuppressive TME to an inflammatory state. GDF15 promotes the generation of peripherally derived inducible Treg (iTreg) cells and enhances the suppressive function of natural Treg (nTreg) cells by interacting with a previously unrecognized receptor CD48 on T cells and thus downregulates STUB1, an E3 ligase that mediates forkhead box P3 (FOXP3) protein degradation. GDF15 neutralizing antibody effectively eradicates HCC and augments the antitumor immunity in mouse.

Conclusions

Our results reveal the generation and function enhancement of Treg cells induced by GDF15 is a new mechanism for HCC-related immunosuppression. CD48 is the first discovered receptor of GDF15 in the immune system which provide the possibility to solve the molecular mechanism of the immunomodulatory function of GDF15. The therapeutic GDF15 blockade achieves HCC clearance without obvious adverse events.
A DSAS-based study of central shoreline change in Jiangsu over 45 years
Authors: Song Yuan , Shen Yongming , Xie Ruofan , Li Jialin
Published: September 2021

A large-scale sand ridge group is distributed in the central Jiangsu coastal area, and a deposition muddy sea bank was developed in the nearshore area. Quantitative monitoring of coastline changes is of great significance for tidal beach development and protection. The shorelines of the central coast of Jiangsu within six periods (1973–2018) were extracted in this study, and their length changes over the years were analyzed. The Digital Shoreline Analysis System (DSAS) was employed to generate a cross section perpendicular to the baseline and calculate the linear regression rate (LRR) of the shoreline, changes in end point rate (EPR), and net shoreline movement (NSM), based on which the shoreline change features were analyzed. The DSAS results indicated that the shorelines in the study area maintained fluctuating growth and presented a continuous advancing trend towards the sea. From the changes in shoreline evolution distance during 1973–2018, the advancing shorelines in the study area accounted for over 50% of the total shorelines and presented first rising and then declining trends with the period of 2003–2013 taken as the time boundary. The average shoreline change rate was 207 m/year, and the periods with the highest change degrees were 1983–1993 and 1993–2013. The shoreline change tended to be stable during 2013–2018, and only a few estuaries and ports underwent obvious erosion and sedimentation.
Theoretical challenges for flavor physics
Authors: Grossman Yuval , Ligeti Zoltan
Published: September 2021

We discuss some highlights of the FCC-$$ee$$

ee

flavor physics program. It will help to explore various aspects of flavor physics: to test precision calculations, to probe nonperturbative QCD methods, and to increase the sensitivity to physics beyond the standard model. In some areas, FCC-$$ee$$

ee

will do much better than current and near-future experiments. We briefly discuss several probes that can be relevant for maximizing the gain from the FCC-$$ee$$

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flavor program.
First in-beam application of thallium bromide semiconductor detectors to particle-induced X-ray emission
Authors: Nogami M. , Hitomi K. , Terakawa A. , Ishii K.
Published: September 2021

For the first time, particle-induced X-ray emission (PIXE) spectra were obtained using TlBr detectors. The TlBr detector was fabricated from a crystal grown with material purified by the zone purification. Its active volume was 1.5 mm × 1.5 mm × 3.1 mm, and it exhibited an energy resolution of a 6.2 keV full-width at half-maximum (FWHM) for 59.5 keV at room temperature. The detector was installed into a PIXE system at Aomori Prefecture Quantum Science Center. A Pb plate target in the PIXE chamber was irradiated with a 20 MeV proton beam, and X-ray peaks for Pb K[Formula: see text] and K[Formula: see text] were successfully detected by the TlBr detector at room temperature.
Monogenic trinomials with non-squarefree discriminant
Authors: Jones Lenny , White Daniel
Published: September 2021

For each integer [Formula: see text], we identify new infinite families of monogenic trinomials [Formula: see text] with non-squarefree discriminant, many of which have small Galois group. Moreover, in certain situations when [Formula: see text] with fixed [Formula: see text] and [Formula: see text], we produce asymptotics on the number of such trinomials with [Formula: see text].
The Bs0 meson decaying into τe mediated by Z′ gauge bosons
Authors: Aranda J. I. , Cruz-Albaro E. , Espinosa-Gómez D. , Montaño J. , Ramírez-Zavaleta F. , Tututi E. S.
Published: September 2021

We calculate bounds for the branching ratio of the [Formula: see text] decay, for the first time, in the context of flavor changing neutral currents mediated by a [Formula: see text] gauge boson, which can arise from five extended models. In this sense, by using experimental measurements on the [Formula: see text] decay and the [Formula: see text] process, we look for constraints of the [Formula: see text] coupling, where the more restrictive bound is offered by the last one. On the other hand, by employing the experimental restriction on the [Formula: see text] decay, the strength of the [Formula: see text] coupling is estimated. Our analysis is based on the more recent experimental results on searches for the [Formula: see text] gauge boson in ATLAS and CMS detectors. In addition, we revisited the [Formula: see text] meson decays by using different approaches not previously reported. The strengths of the [Formula: see text] and [Formula: see text] couplings were estimated by employing experimental restrictions on the [Formula: see text] decay and the [Formula: see text] conversion rate, respectively. Thus, we predict the following upper bounds: [Formula: see text], [Formula: see text] and [Formula: see text].
Highly dispersive optical soliton perturbation of Kudryashov’s arbitrary form having sextic-power law refractive index
Authors: Elsherbeny Ahmed M. , El-Barkouky Reda , Seadawy Aly R. , Ahmed Hamdy M. , El-Hassani Rabab M. I. , Arnous Ahmed H.
Published: September 2021

In this research paper, a simple integration scheme is executed to secure new dark and singular soliton solutions for the highly dispersive nonlinear Schrödinger’s equation having Kudryashov’s arbitrary form with generalized nonlocal laws and sextic-power law refractive index.
Weierstrass and Jacobi elliptic solutions with some new dromions to Maccari system
Authors: Rizvi S. T. R. , Seadawy Aly R. , Younis M. , Ahmad S. , Ali K.
Published: September 2021

This paper studies Attilio Maccari (AM) system for some new solitary wave solutions. We used sub-ODE scheme to find kink shape, bell type, Weierstrass and Jacobi elliptic, hyperbolic, periodic and other solitary wave solutions under some constraint conditions. We will also present our results graphically in distinct dimensions.
Study vibrational and structural properties of Cu3SeTe by raman spectroscopy and XRD
Authors: Ibrahimova S. I. , Jabarov S. H. , Aliyeva N. A. , Aliyev Y. I.
Published: September 2021

The compounds Cu3SeTe were synthesized, the crystal structure and atomic dynamics were studied. As a result of X-ray diffraction studies, it was determined that the crystal structure of this compound corresponds to the cubic symmetry of the space group P-43 m. The studies of atomic dynamics were carried out by the method of Raman spectroscopy in the frequency range [Formula: see text]–800 cm[Formula: see text]. It was found that the Raman modes obtained at frequencies [Formula: see text], 91.47, 119.83, 139.51, 208.18 and 266.41 cm[Formula: see text] correspond to vibrations of metal–chalcogen and chalcogen–chalcogen bonds.
Painlevé analysis, auto-Bäcklund transformation and analytic solutions for modified KdV equation with variable coefficients describing dust acoustic solitary structures in magnetized dusty plasmas
Authors: Singh Shailendra , Ray S. Saha
Published: September 2021

In this paper, variable coefficients mKdV equation is examined by using Painlevé analysis and auto-Bäcklund transformation method. The proposed equation is an important equation in magnetized dusty plasmas. The Painlevé analysis is used to determine the integrability whereas an auto-Bäcklund transformation technique is being explored to derive unique family of analytical solutions for variable coefficients mKdV equation. New kink–antikink and periodic-kink- type soliton solutions have been determined successfully for the considered equation. This paper shows that auto-Bäcklund transformation method is effective, direct and easy to use, and used to determine the analytic soliton solutions of various nonlinear evolution equations in the field of science and engineering. The results are plotted graphically to signify the potency and applicability of this proposed scheme for solving the above considered equation. The obtained results are in the form of soliton-like solutions, solitary wave solutions, exponential and trigonometric function solutions. Therefore, these solutions help us to understand the potential and physical behaviors of the proposed equation.
CHAOTIC BEHAVIOR OF BHALEKAR–GEJJI DYNAMICAL SYSTEM UNDER ATANGANA–BALEANU FRACTAL FRACTIONAL OPERATOR
Authors: AHMAD SHABIR , ULLAH AMAN , AKGÜL ALI , ABDELJAWAD THABET
Published: September 2021

In this paper, a new set of differential and integral operators has recently been proposed by Abdon et al. by merging the fractional derivative and the fractal derivative, taking into account nonlocality, memory and fractal effects. These operators have demonstrated the complex behavior of many physical, which generally does not predict in ordinary operators or sometimes in fractional operators also. In this paper, we investigate the proposed model by replacing the classic derivative by fractal–fractional derivatives in which fractional derivative is taken in Atangana–Baleanu Caputo sense to study the complex behavior due to nonlocality, memory and fractal effects. Through Schauder’s fixed point theorem, we establish existence theory to ensure that the model posseses at least one solution. Also, Banach fixed theorem guarantees the uniqueness of solution of the proposed model. By means of nonlinear functional analysis, we prove that the proposed model is Ulam–Hyers stable under the new fractal–fractional derivative. We establish the numerical results of the considered model through Lagrangian piece-wise interpolation. For the different values of fractional order and fractal dimension, we study the chaos behavior of the proposed model via simulation at 2D and 3D phase. We show the effect of fractal dimension on integer and fractional order through simulations.
CERTAIN DEVELOPMENTS ON SOLUTIONS OF DYNAMIC INEQUALITIES IN THE PREMISE OF TIME SCALES
Authors: KHAN ZAREEN A. , KAYNAK KADIR
Published: September 2021

On the grounds of few perceived Gronwall inequalities, we inspect some new relevant nonlinear dynamic inequalities on time scales related to one independent variable. To guarantee the evenness of information division and with the conversation of peculiar cases, it is indicated that these inequalities catch dynamic, delay, Volterra–Fredholm, discrete, fractional, etc. The inequalities suggested right here to other specific bounds on unknown parameters may be handled as powerful equipment for determining the features of various dynamic equations on time scales. It is trusted that this research plan will open new possibilities in in-depth examination of time scale scheme structure of varying nature.
INFLUENCE OF THE INLET PRESSURE ON IMPULSE CHARACTERISTICS OF ALUMINUM SAMPLES
Authors: YANG ZHONGGUO , YI SHUJUAN , ZHAO SHENGXUE , SHI WANG
Published: September 2021

In this work, the cavitation water jet technique was used to clean the inner walls of oil pipes after tertiary oil recovery. The surface morphology, depth of impinging pits, and corrosion resistance of aluminum samples after impingement with the cavitation water jet were examined using scanning electron microscopy (SEM), 3D microscopy, and an electrochemical workstation. When the inlet pressure was higher than 3[Formula: see text]MPa, the number of cavitation bubbles generated by the cavitation nozzle increased with an increase in inlet pressure. Moreover, the cleaning effect that the cavitation water jet had on the aluminum samples was higher than that of general water jet technology. There were no obvious changes to the surface of the aluminum samples when the inlet pressure was decreased to 13[Formula: see text]MPa. Meanwhile, the mass loss of aluminum samples also increased. However, the internal corrosion resistance of the pipe wall after impact was relatively low. These results indicate that the impinging efficiency of the cavitation water jet was obviously enhanced and the degree of damage to the oil pipe wall was low at an inlet pressure of 15[Formula: see text]MPa. The best target distance was 8–12[Formula: see text]mm, and at this point, the jet flushing effect was the best. Moreover, the jet velocity at the outlet cavity was 184[Formula: see text]m/s, and the jet strike area was 250[Formula: see text]mm2.
Multi-Robot SLAM in Dynamic Environments with Parallel Maps
Authors: Badalkhani Sajad , Havangi Ramazan , Farshad Mohsen
Published: September 2021

There is an extensive literature regarding multi-robot simultaneous localization and mapping (MRSLAM). In most part of the research, the environment is assumed to be static, while the dynamic parts of the environment degrade the estimation quality of SLAM algorithms and lead to inherently fragile systems. To enhance the performance and robustness of the SLAM in dynamic environments (SLAMIDE), a novel cooperative approach named parallel-map (p-map) SLAM is introduced in this paper. The objective of the proposed method is to deal with the dynamics of the environment, by detecting dynamic parts and preventing the inclusion of them in SLAM estimations. In this approach, each robot builds a limited map in its own vicinity, while the global map is built through a hybrid centralized MRSLAM. The restricted size of the local maps, bounds computational complexity and resources needed to handle a large scale dynamic environment. Using a probabilistic index, the proposed method differentiates between stationary and moving landmarks, based on their relative positions with other parts of the environment. Stationary landmarks are then used to refine a consistent map. The proposed method is evaluated with different levels of dynamism and for each level, the performance is measured in terms of accuracy, robustness, and hardware resources needed to be implemented. The method is also evaluated with a publicly available real-world data-set. Experimental validation along with simulations indicate that the proposed method is able to perform consistent SLAM in a dynamic environment, suggesting its feasibility for MRSLAM applications.
Uncertain Independent Increment Processes are Contour Processes
Authors: Yao Kai
Published: September 2021

Uncertain processes are used to model dynamic indeterminate systems associated with human uncertainty, and uncertain independent increment processes are a type of uncertain processes with independent uncertain increments. This paper mainly verifies a basic property about the sample paths of uncertain independent increment processes, which states that uncertain independent increment processes defined on a continuous uncertainty space are contour processes, a type of uncertain processes with a spectrum of sample paths as the skeletons. Based on this property, the extreme values and the time integral of an uncertain independent increment process are investigated, and their inverse uncertainty distributions are obtained.
Finite Element Analysis of Impact-Induced Damage in Pressurized Hybrid Composites Pipes
Authors: Maziz Ammar , Tarfaoui Mostapha , Rechak Said , Nachtane Mourad , Gemi Lokman
Published: September 2021

The high mechanical performance of filament wound hybrid composite pipes can be adversely affected by their low resistance to accidental impact. Loads of dynamic origin are dangerous and cause consequences on the operation of pipes because the damage is often not detected and can affect the structural integrity of composite pipes. In this work, a finite element (FE) model of pressurized hybrid composite pipe is developed and performed to predict the damage initiation and evolution under low-velocity impact through simulations with ABAQUS/Explicit. Hashin’s failure theory is used as failure criterion. At the first stage, load–time histories, and impactor displacement time limits are estimated in an FE model. The numerical results are confronted with the experimental values published in the literature. Once the model was validated, damage initiation and propagation were analyzed, where it is observed that damage mainly occurs by matrix cracking, damage evolution in the matrix in tension, compression and shear are presented and discussed in detail.
Natural Frequency Analysis of Multilayer Truncated Conical Shells Containing Quiescent Fluid on Elastic Foundation with Different Boundary Conditions
Authors: Paknejad Reza , Ghasemi Faramarz Ashenai , Fard Keramat Malekzadeh
Published: September 2021

In this paper, natural frequency of a multilayer truncated conical composite shell conveying quiescent fluid on elastic foundation with different boundary conditions is investigated and analyzed. The governing equations are presented based on the first-order shear deformation theory. Bernoulli’s equation and velocity potential have been used in the shell-fluid interface to obtain the fluid pressure. The fluid used in this study is considered non-compressible and non-viscous. The beam functions and the Galerkin weight functions method are used to describe and solve the coupled system of differential equations. Three types of boundary conditions are considered to investigate the natural frequency of the conical shells. The results show that the presence of the fluid in the conical shell reduces the fundamental natural frequency values. Also, by changing the semi-vertex conical angle from [Formula: see text] to [Formula: see text] for the simply support boundary conditions, the fundamental natural frequency value for the composite conical shell without and with fluid increases, and the presence of the elastic foundation increases the frequencies of the empty and full-fluid composite conical shells.
Properties Analysis of Disk Spring with Effects of Asymmetric Variable Friction
Authors: Chen Renzhen , Li Xiaopeng , Xu Jinchi , Yang Zemin , Yang Hexu
Published: September 2021

The primary objective of this fundamental research is to investigate the mechanical properties of the disk spring when the friction at the contact edges is asymmetric and varies with the load. The contact mechanics study shows that the static friction and static friction coefficient on fractal surfaces change depending on the normal load. In this paper, a fractal contact model based on the W-M function is used to explore the connection between the static friction and the normal load. Subsequently, taking into account the asymmetry of the contact surface at the edge, the variable static friction coefficient is brought into the existing model to obtain an improved static model of the disk spring. Different fractal dimensions, frictional states and free heights are considered under quasi-static loading condition, the relative errors between this paper and the method using Coulomb friction are also calculated, and experimental validation was performed. The static stiffness and force hysteresis of the disk spring for different forms of asymmetric variable friction are discussed. It is shown that using the variable friction model can improve the computational accuracy of the disk spring model under small loads and help to improve the design and control accuracy of preload and vibration isolation equipment using the disk spring as a component.
Contact Damping and Stiffness Calculation Model for Rough Surface Considering Lubrication in Involute Spur Gear
Authors: Cheng Gong , Xiao Ke , Wang Jiaxu
Published: September 2021

The contact properties of an interface are crucial to the performance of equipment, and it is necessary to study the contact damping and contact stiffness, especially in the case of mixed lubrication. A calculation model for contact damping and contact stiffness considering lubrication was proposed on the basis of the KE contact model and mixed elastohydrodynamic lubrication theory. Both the damping and the stiffness were composed of the oil film portion and the asperity contact portion. Since the damping and the stiffness of oil film mainly depended on the film thickness and the pressure, which can be obtained with the mixed lubrication model, another crucial point was to figure out the contribution of asperity contact. Ignoring the effect of the tangential deformation, the stiffness and the load determined with the normal deformation of the asperity were obtained. Then, the contact damping and the contact stiffness considering lubrication could be derived. Finally, the model was applied to the study of contact damping and stiffness of the involute spur gear.
A New Representation for Viscoelastic Behavior of Materials in Two- and Three-Dimensional Problems
Authors: Rajabi Kaveh , Khajehsaeid Hesam , Li Li , Ghahnavieh Sina
Published: September 2021

The main objective of this study is to develop a set of equations, in which any desirable rheological model can be employed to investigate the behavior of viscoelastic materials (VMs) in two- or three-dimensional settings within the scope of small deformations. Application of the differential-form constitutive equations in 3D problems has been mainly limited to the isotropic materials. On the other hand, the integral-form constitutive equations are mostly unfavorable in terms of computational costs. To the best knowledge of the authors, in general, there is no interrelation between the differential-form and the integral-form viscoelastic constitutive equations in the 3D theory of linear viscoelasticity. This study tends to link the differential and the integral forms of linear viscoelasticity in a general setting. As a consequence, for example, relaxation moduli of a VM can be formulated in terms of model parameters, i.e., spring constants and viscosity coefficients, of any desirable rheological model. Some numerical examples are also provided to support the efficiency of the proposed formulation in 2D and 3D loading scenarios.