bluuebunny/crossref_metadata_2025 huggingface dataset:
Alternative to prophylactic antibiotics for the treatment of recurrent urinary tract infections in women: multicentre, open label, randomised, non-inferiority trial
Authors: Harding Chris , Mossop Helen , Homer Tara , Chadwick Thomas , King William , Carnell Sonya , Lecouturier Jan , Abouhajar Alaa , Vale Luke , Watson Gillian , Forbes Rebecca , Currer Stephanie , Pickard Robert , Eardley Ian , Pearce Ian , Thiruchelvam Nikesh , Guerrero Karen , Walton Katherine , Hussain Zahid , Lazarowicz Henry , Ali Ased
Published: March 2022

Objective

To test and compare the efficacy of methenamine hippurate for prevention of recurrent urinary tract infections with the current standard prophylaxis of daily low dose antibiotics.

Design

Multicentre, open label, randomised, non-inferiority trial.

Setting

Eight centres in the UK, recruiting from June 2016 to June 2018.

Participants

Women aged ≥18 years with recurrent urinary tract infections, requiring prophylactic treatment.

Interventions

Random assignment (1:1, using permuted blocks of variable length via a web based system) to receive antibiotic prophylaxis or methenamine hippurate for 12 months. Treatment allocation was not masked and crossover between arms was allowed.

Main outcome measure

Absolute difference in incidence of symptomatic, antibiotic treated, urinary tract infections during treatment. A patient and public involvement group predefined the non-inferiority margin as one episode of urinary tract infection per person year. Analyses performed in a modified intention-to-treat population comprised all participants observed for at least six months.

Results

Participants were randomly assigned to antibiotic prophylaxis (n=120) or methenamine hippurate (n=120). The modified intention-to-treat analysis comprised 205 (85%) participants (antibiotics, n=102 (85%); methenamine hippurate, n=103 (86%)). Incidence of antibiotic treated urinary tract infections during the 12 month treatment period was 0.89 episodes per person year (95% confidence interval 0.65 to 1.12) in the antibiotics group and 1.38 (1.05 to 1.72) in the methenamine hippurate group, with an absolute difference of 0.49 (90% confidence interval 0.15 to 0.84) confirming non-inferiority. Adverse reactions were reported by 34/142 (24%) in the antibiotic group and 35/127 (28%) in the methenamine group and most reactions were mild.

Conclusion

Non-antibiotic prophylactic treatment with methenamine hippurate might be appropriate for women with a history of recurrent episodes of urinary tract infections, informed by patient preferences and antibiotic stewardship initiatives, given the demonstration of non-inferiority to daily antibiotic prophylaxis seen in this trial.

Trial registration

ISRCTN70219762
.
Outcome of lifestyle intervention in relation to duration of pre-diabetes: the Pathobiology and Reversibility of Prediabetes in a Biracial Cohort (PROP-ABC) study
Authors: Dagogo-Jack Samuel , Umekwe Nkiru , Brewer Amy A , Owei Ibiye , Mupparaju Vamsee , Rosenthal Renate , Wan Jim
Published: March 2022

Introduction

In studies that enrolled people with prevalent pre-diabetes of unknown duration, lifestyle intervention (LI) delayed progression to type 2 diabetes (T2D) but did not reverse pre-diabetes in most participants. Here, we assessed the effects of LI among individuals with pre-diabetes of known duration to determine whether outcomes are related to duration of pre-diabetes.

Research design and methods

The Pathobiology and Reversibility of Prediabetes in a Biracial Cohort study initiated LI in subjects with incident pre-diabetes during follow-up of initially normoglycemic African Americans and European Americans with parental T2D. Participants were stratified into those initiating LI after <3, 3–5, or >5 years of pre-diabetes diagnosis. Assessments included anthropometry, body fat, fasting and 2-hour plasma glucose (FPG, 2hPG), and insulin sensitivity and secretion. The outcomes were normal glucose regulation (NGR; ie, normal FPG and 2hPG), persistent pre-diabetes, or T2D. Participants who maintained normal FPG and normal 2hPG levels during follow-up served as the control. The control subjects did not receive lifestyle or other intervention to alter the course of glycemia or body weight.

Results

Of 223 participants (age 53.3±9.28 years, body mass index 30.6±6.70 kg/m2), 72 (control) maintained normoglycemia during follow-up and 138 subjects with incident pre-diabetes initiated LI after 4.08±2.02 years (range 3 months–8.3 years) of diagnosis. Compared with control, LI participants showed decrease in glucose, weight, and body fat; 42.8% reverted to NGR, 50% had persistent pre-diabetes, and 7.2% developed T2D after 5 years. These outcomes were similar across race and pre-diabetes duration strata, but greater glycemic decrease occurred when LI was initiated within 5 years of pre-diabetes diagnosis.

Conclusions

Ninety-three per cent of adults with parental T2D who initiated LI within 3 months to 8.3 years of developing pre-diabetes did not progress to T2D; nearly half reverted to NGR.

Trial registration numberNCT02027571.
Comprehensive compartmental model and calibration algorithm for the study of clinical implications of the population-level spread of COVID-19: a study protocol
Authors: Robinson Brandon , Edwards Jodi D , Kendzerska Tetyana , Pettit Chris L , Poirel Dominique , Daly John M , Ammi Mehdi , Khalil Mohammad , Taillon Peter J , Sandhu Rimple , Mills Shirley , Mulpuru Sunita , Walker Thomas , Percival Valerie , Dolean Victorita , Sarkar Abhijit
Published: March 2022

Introduction

The complex dynamics of the coronavirus disease 2019 (COVID-19) pandemic has made obtaining reliable long-term forecasts of the disease progression difficult. Simple mechanistic models with deterministic parameters are useful for short-term predictions but have ultimately been unsuccessful in extrapolating the trajectory of the pandemic because of unmodelled dynamics and the unrealistic level of certainty that is assumed in the predictions.

Methods and analysis

We propose a 22-compartment epidemiological model that includes compartments not previously considered concurrently, to account for the effects of vaccination, asymptomatic individuals, inadequate access to hospital care, post-acute COVID-19 and recovery with long-term health complications. Additionally, new connections between compartments introduce new dynamics to the system and provide a framework to study the sensitivity of model outputs to several concurrent effects, including temporary immunity, vaccination rate and vaccine effectiveness. Subject to data availability for a given region, we discuss a means by which population demographics (age, comorbidity, socioeconomic status, sex and geographical location) and clinically relevant information (different variants, different vaccines) can be incorporated within the 22-compartment framework. Considering a probabilistic interpretation of the parameters allows the model’s predictions to reflect the current state of uncertainty about the model parameters and model states. We propose the use of a sparse Bayesian learning algorithm for parameter calibration and model selection. This methodology considers a combination of prescribed parameter prior distributions for parameters that are known to be essential to the modelled dynamics and automatic relevance determination priors for parameters whose relevance is questionable. This is useful as it helps prevent overfitting the available epidemiological data when calibrating the parameters of the proposed model. Population-level administrative health data will serve as partial observations of the model states.

Ethics and dissemination

Approved by Carleton University’s Research Ethics Board-B (clearance ID: 114596). Results will be made available through future publication.
Complementary feeding practices and the associated risk of childhood obesity among ethnic minority groups living in high-income countries: protocol for a systematic review and meta-analysis
Authors: Tsenoli Maido , Khan Moien A B , Östlundh Linda , Arora Teresa , Omar Omar
Published: March 2022

Introduction

Complementary feeding (CF) is defined as the period from when exclusive breast milk and formula are no longer sufficient for meeting the infant’s nutritional needs. The CF period occurs from birth to 23 months of age. Though the recommended guidelines for introducing CF is from around 6 months of age, data indicates that some infants are introduced to food earlier than 6 months which can predispose children to obesity and overweight. Obesity in ethnic minority groups (EMG) is higher than their native counterparts and often tracks into adulthood. Hence, our aim was to conduct a systematic review and meta-analysis on the available literature to identify the risk of childhood overweight/obesity associated with CF practices concerning their timing, as well as the frequency and type of CF food introduced. We focused specifically on EMG children living in high-income countries.

Methods and analysis

A methodological literature search surrounding childhood obesity and overweight (COO) risk associated with CF practices will be conducted in May 2021 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. The following academic databases will be methodologically searched: PubMed, EMBASE, PsycINFO, CINAHL, SCOPUS, Cochrane Library and the WHO Global Index Medicus. Three independent researchers will be involved in independent screening and review the included articles based on the predefined inclusion and exclusion criteria. Where conflicts arise during the screening process, it will be resolved through discourse until a consensus is reached. Information on CF practices and anthropometric measurements will be extracted to ascertain the risk of COO. For this study, WHO body mass index for age and sex percentiles, Centers for Disease Control and Prevention classification and other recognised country-specific classifications will be utilised for the outcome.

Ethics and dissemination

Formal ethical approval is not needed as the results will be drawn from currently available published literature. Outcomes of the review will be shared through peer-reviewed publications.

PROSPERO registration number

CRD42021246029.
Assessing the reliability of phone surveys to measure reproductive, maternal and child health knowledge among pregnant women in rural India: a feasibility study
Authors: Ng Angela , Mohan Diwakar , Shah Neha , Scott Kerry , Ummer Osama , Chamberlain Sara , Bhatnagar Aarushi , Dhar Diva , Agarwal Smisha , Ved Rajani , LeFevre Amnesty Elizabeth
Published: March 2022

Objectives

Efforts to understand the factors influencing the uptake of reproductive, maternal, newborn, child health and nutrition (RMNCH&N) services in high disease burden low-resource settings have often focused on face-to-face surveys or direct observations of service delivery. Increasing access to mobile phones has led to growing interest in phone surveys as a rapid, low-cost alternatives to face-to-face surveys. We assess determinants of RMNCH&N knowledge among pregnant women with access to phones and examine the reliability of alternative modalities of survey delivery.

Participants

Women 5–7 months pregnant with access to a phone.

Setting

Four districts of Madhya Pradesh, India.

Design

Cross-sectional surveys administered face-to-face and within 2 weeks, the same surveys were repeated among two random subsamples of the original sample: face-to-face (n=205) and caller-attended telephone interviews (n=375). Bivariate analyses, multivariable linear regression, and prevalence and bias-adjusted kappa scores are presented.

Results

Knowledge scores were low across domains: 52% for maternal nutrition and pregnancy danger signs, 58% for family planning, 47% for essential newborn care, 56% infant and young child feeding, and 58% for infant and young child care. Higher knowledge (≥1 composite score) was associated with older age; higher levels of education and literacy; living in a nuclear family; primary health decision-making; greater attendance in antenatal care and satisfaction with accredited social health activist services. Survey questions had low inter-rater and intermodal reliability (kappa<0.70) with a few exceptions. Questions with the lowest reliability included true/false questions and those with unprompted, multiple response options. Reliability may have been hampered by the sensitivity of the content, lack of privacy, enumerators’ and respondents’ profile differences, rapport, social desirability bias, and/or enumerator’s ability to adequately convey concepts or probe.

Conclusions

Phone surveys are a reliable modality for generating population-level estimates data about pregnant women’s knowledge, however, should not be used for individual-level tracking.

Trial registration number

NCT03576157.
Brain Oxygen Optimization in Severe Traumatic Brain Injury (BOOST-3): a multicentre, randomised, blinded-endpoint, comparative effectiveness study of brain tissue oxygen and intracranial pressure monitoring versus intracranial pressure alone
Authors: Bernard Francis , Barsan William , Diaz-Arrastia Ramon , Merck Lisa H , Yeatts Sharon , Shutter Lori A
Published: March 2022

Introduction

Management of traumatic brain injury (TBI) includes invasive monitoring to prevent secondary brain injuries. Intracranial pressure (ICP) monitor is the main measurement used to that intent but cerebral hypoxia can occur despite normal ICP. This study will assess whether the addition of a brain tissue oxygenation (PbtO2) monitor prevents more secondary injuries that will translate into improved functional outcome.

Methods and analysis

Multicentre, randomised, blinded-endpoint comparative effectiveness study enrolling 1094 patients with severe TBI monitored with both ICP and PbtO2. Patients will be randomised to medical management guided by ICP alone (treating team blinded to PbtO2values) or both ICP and PbtO2. Management is protocolised according to international guidelines in a tiered approach fashion to maintain ICP <22 mm Hg and PbtO2>20 mm Hg. ICP and PbtO2will be continuously recorded for a minimum of 5 days. The primary outcome measure is the Glasgow Outcome Scale-Extended performed at 180 (±30) days by a blinded central examiner. Favourable outcome is defined according to a sliding dichotomy where the definition of favourable outcome varies according to baseline severity. Severity will be defined according to the probability of poor outcome predicted by the IMPACT core model. A large battery of secondary outcomes including granular neuropsychological and quality of life measures will be performed.

Ethics and dissemination

This has been approved by Advarra Ethics Committee (Pro00030585). Results will be presented at scientific meetings and published in peer-reviewed publications.

Trial registration number

ClinicalTrials.gov Registry (NCT03754114).
Increasing the uptake in a general practice prostate cancer screening programme
Authors: Limaye Neil , Zorzato Daniele , Nadarajasundaram Aaruran , Ong Sabrina B Y
Published: March 2022

Background

Prostate cancer (PC) is the second most common cause of cancer deaths among males worldwide. Prostate-specific antigen (PSA) is a predictive indicator of prostate pathology. Men with elevated PSA levels are at increased risk of developing PC. There is currently no UK national PC screening programme, therefore patients often present to general practices (GPs) at later stages of pathology, worsening patient prognosis and outcomes.

Local problem

The location of the GP surgery had a large patient population at increased risk of PC, namely Afro-Caribbean/Asian males.

Methods

We conducted baseline measurements to identify male patients over the age of 65 and/or male patients who were at high risk of developing PC. These included previous referred patients or patients with a PSA over 10.0. We then implemented three plan-do-study-act (PDSA) cycles and measured their effect after 2 weeks of starting the respective intervention.

Interventions

PDSA1: Generating a list of target patients who have not had repeat/follow-up/referral and directly contacting by telephone to invite them for a blood test.

PDSA2: Creating patient-specific electronic pop-up reminders on the electronic-patient-record system for PSA follow-up/referral/repeat test.

Planned PDSA3: Patient education of prostate health and general self-checking, as well as benefits/risks of undergoing PSA screening in the form of patient focus groups and informative leaflets.

Results

We identified 220 male patients over 65 registered at a large South London GP surgery. 77.7% of eligible patients had a PSA measurement since 1 April 2019. Our results showed an overall increase in screening of 13.5% from baseline.

Conclusions

Our project identified patients that may potentially have undiagnosed prostate pathology. However, a key factor for not reaching our goal was blood test refusal. This was further exacerbated by the COVID-19 pandemic, impacting the capacity to disseminate appropriate information to the local population on the importance of PSA screening.
Tendency to call an ambulance or attend an emergency department for minor or non-urgent problems: a vignette-based population survey in Britain
Authors: O'Cathain Alicia , Simpson Rebecca , Phillips Miranda , Knowles Emma
Published: March 2022

Background

There are concerns about high levels of demand for emergency health services. The aim was to identify the characteristics of the British population with a tendency to contact emergency medical services and EDs for minor or non-urgent problems.

Methods

A survey of the British adult population in 2018. Six vignettes were constructed about illness in adults (cough/sore throat or diarrhoea/vomiting), injury in adults (sore rib or back pain) and fever in children (occurring weekday or weekend).

Results

The response rate was 42%, with 2906 respondents. 11% (319/2716) of respondents selected to contact an ambulance and 43% ED, mainly for the vignettes about fever in children and sore rib. Males, people from ethnic minority communities and older people had a tendency to contact emergency services for minor problems. Tendency to call an ambulance was also characterised by ‘low resources’ (manual or unskilled occupations, no car, low health literacy), worry that a symptom might be serious, distress (feeling overwhelmed by health problems) and frequent use of EDs. For EDs, there was an attraction to EDs because of availability of tests.

Conclusion

Whereas use of emergency ambulances for minor or non-urgent problems appeared to be driven by people’s lack of resources, including lack of transport, use of EDs appeared to be driven by their attractive characteristic of offering tests quickly.
Evaluation of antithrombotic use and COVID-19 outcomes in a nationwide atrial fibrillation cohort
Authors: Handy Alex , Banerjee Amitava , Wood Angela M , Dale Caroline , Sudlow Cathie L M , Tomlinson Christopher , Bean Daniel , Thygesen Johan H , Mizani Mehrdad A , Katsoulis Michail , Takhar Rohan , Hollings Sam , Denaxas Spiros , Walker Venexia , Dobson Richard , Sofat Reecha
Published: March 2022

Objective

To evaluate antithrombotic (AT) use in individuals with atrial fibrillation (AF) and at high risk of stroke (CHA2DS2-VASc score ≥2) and investigate whether pre-existing AT use may improve COVID-19 outcomes.

Methods

Individuals with AF and CHA2DS2-VASc score ≥2 on 1 January 2020 were identified using electronic health records for 56 million people in England and were followed up until 1 May 2021. Factors associated with pre-existing AT use were analysed using logistic regression. Differences in COVID-19-related hospitalisation and death were analysed using logistic and Cox regression in individuals with pre-existing AT use versus no AT use, anticoagulants (AC) versus antiplatelets (AP), and direct oral anticoagulants (DOACs) versus warfarin.

Results

From 972 971 individuals with AF (age 79 (±9.3), female 46.2%) and CHA2DS2-VASc score ≥2, 88.0% (n=856 336) had pre-existing AT use, 3.8% (n=37 418) had a COVID-19 hospitalisation and 2.2% (n=21 116) died, followed up to 1 May 2021. Factors associated with no AT use included comorbidities that may contraindicate AT use (liver disease and history of falls) and demographics (socioeconomic status and ethnicity). Pre-existing AT use was associated with lower odds of death (OR=0.92, 95% CI 0.87 to 0.96), but higher odds of hospitalisation (OR=1.20, 95% CI 1.15 to 1.26). AC versus AP was associated with lower odds of death (OR=0.93, 95% CI 0.87 to 0.98) and higher hospitalisation (OR=1.17, 95% CI 1.11 to 1.24). For DOACs versus warfarin, lower odds were observed for hospitalisation (OR=0.86, 95% CI 0.82 to 0.89) but not for death (OR=1.00, 95% CI 0.95 to 1.05).

Conclusions

Pre-existing AT use may be associated with lower odds of COVID-19 death and, while not evidence of causality, provides further incentive to improve AT coverage for eligible individuals with AF.
Exercise oxygen pulse kinetics in patients with hypertrophic cardiomyopathy
Authors: Mapelli Massimo , Romani Simona , Magrì Damiano , Merlo Marco , Cittar Marco , Masè Marco , Muratori Manuela , Gallo Giovanna , Sclafani Matteo , Carriere Cosimo , Zaffalon Denise , Salvioni Elisabetta , Mattavelli Irene , Vignati Carlo , De Martino Fabiana , Rovai Sara , Autore Camillo , Sinagra Gianfranco , Agostoni Piergiuseppe
Published: March 2022

Objectives

Reduced cardiac output (CO) has been considered crucial in symptoms’ genesis in hypertrophic cardiomyopathy (HCM). Absolute value and temporal behaviour of O2-pulse (oxygen uptake/heart rate (VO2/HR)), and the VO2/work relationship during exercise reflect closely stroke volume (SV) and CO changes, respectively. We hypothesise that adding O2-pulse absolute value and kinetics, and VO2/work relationship to standard cardiopulmonary exercise testing (CPET) could help identify more exercise-limited patients with HCM.

Methods

CPETs were performed in 3 HCM dedicated clinical units. We retrospectively enrolled non-end-stage consecutive patients with HCM, grouped according to left ventricle outflow tract obstruction (LVOTO) at rest or during Valsalva manoeuvre (72% of patients with LVOTO <30; 10% between 30 and 49 and 18% ≥50 mm Hg). We evaluated the CPET response in HCM focusing on parameters strongly associated with SV and CO, such as O2-pulse and VO2, respectively, considering their absolute values and temporal behaviour during exercise.

Results

We included 312 patients (70% males, age 49±18 years). Peak VO2(percentage of predicted), O2-pulse and ventilation to carbon dioxide production (VE/VCO2) slope did not change across LVOTO groups. Ninety-six (31%) patients with HCM presented an abnormal O2-pulse temporal behaviour, irrespective of LVOTO values. These patients showed lower peak systolic pressure, workload (106±45 vs 130±49 W), VO2(21.3±6.6 vs 24.1±7.7 mL/min/kg; 74%±17% vs 80%±20%) and O2-pulse (12 (9–14) vs 14 (11–17) mL/beat), with higher VE/VCO2slope (28 (25–31) vs 27 (24–31)) (p<0.005 for all). Only 2 patients had an abnormal VO2/work slope.

Conclusion

None of the frequently used CPET parameters, either as absolute values or dynamic relationships, were associated with LVOTO. Differently, an abnormal temporal behaviour of O2-pulse during exercise, which is strongly related to inadequate SV increase, correlates with reduced functional capacity (peak and anaerobic threshold VO2and workload) and increased VE/VCO2slope, identifying more advanced disease irrespectively of LVOTO.
Exosomal CD73 from serum of patients with melanoma suppresses lymphocyte functions and is associated with therapy resistance to anti-PD-1 agents
Authors: Turiello Roberta , Capone Mariaelena , Morretta Elva , Monti Maria Chiara , Madonna Gabriele , Azzaro Rosa , Del Gaudio Pasquale , Simeone Ester , Sorrentino Antonio , Ascierto Paolo A , Morello Silvana
Published: March 2022

Background

CD73 is an ectonucleotidase producing the immunosuppressor mediator adenosine. Elevated levels of circulating CD73 in patients with cancer have been associated with disease progression and poor response to immunotherapy. Immunosuppressive pathways associated with exosomes can affect T-cell function and the therapeutic efficacy of anti-programmed cell-death protein 1 (anti-PD-1) therapy. Here, we conducted a retrospective pilot study to evaluate levels of exosomal CD73 before and early during treatment with anti-PD-1 agents in patients with melanoma and its potential contribution to affect T-cell functions and to influence the clinical outcomes of anti-PD-1 monotherapy.

Methods

Exosomes were isolated by mini size exclusion chromatography from serum of patients with melanoma (n=41) receiving nivolumab or pembrolizumab monotherapy. Expression of CD73 and programmed death-ligand 1 (PD-L1) were evaluated on exosomes enriched for CD63 by on-bead flow cytometry. The CD73 AMPase activity was evaluated by mass spectrometry, also in the presence of selective inhibitors of CD73. Interferon (IFN)-γ production and granzyme B expression were measured in CD3/28 activated T cells incubated with exosomes in presence of the CD73 substrate AMP. Levels of CD73 and PD-L1 on exosomes were correlated with therapy response. Exosomes isolated from healthy subjects were used as control.

Results

Isolated exosomes carried CD73 on their surface, which is enzymatically active in producing adenosine. Incubation of exosomes with CD3/28 activated T cells in the presence of AMP resulted in a significant reduction of IFN-γ release, which was reversed by the CD73 inhibitor APCP or by the selective A2A adenosine receptor antagonist ZM241385. Expression levels of exosomal CD73 from serum of patients with melanoma were not significantly different from those in healthy subjects. Early on-treatment, expression levels of both CD73 and PD-L1 on exosomes isolated from patients receiving pembrolizumab or nivolumab monotherapy were significantly increased compared with baseline. Early during therapy exosomal PD-L1 increased in responders, while exosomal CD73 resulted significantly increased in non-responders.

Conclusions

CD73 expressed on exosomes from serum of patients with melanoma produces adenosine and contributes to suppress T-cell functions. Early on-treatment, elevated expression levels of exosomal CD73 might affect the response to anti-PD-1 agents in patients with melanoma who failed to respond to therapy.
Estimating QCD-factorization amplitudes through SU(3) symmetry in $$B\rightarrow P P$$ decays
Authors: Huber Tobias , Tetlalmatzi-Xolocotzi Gilberto
Published: March 2022

We estimate the potential size of the weak annihilation amplitudes in QCD factorization as allowed by experimental data. To achieve this goal, we establish a connection between the amplitudes in the QCD factorization and the so-called topological and SU(3)-invariant descriptions. Our approach is based purely on the analysis of the tensor structure of the decay amplitudes. By focusing on the processes $$B\rightarrow P P$$

B
→
P
P

and considering data from CP asymmetries and branching fractions, we perform a global fit to the SU(3)-irreducible quantities assuming minimal theoretical bias. Subsequently we translate the outcome to the QCD factorization decomposition, and find that the most constrained weak annihilation amplitudes are below 0.04. However, in view of the large uncertainties in several of the experimental input parameters, values up to $$\sim 0.3$$

∼
0.3

are allowed in certain cases.
Testing the upper bound on the speed of scrambling with an analogue of Hawking radiation using trapped ions
Authors: Tian Zehua , Lin Yiheng , Fischer Uwe R. , Du Jiangfeng
Published: March 2022

The Lyapunov exponent of a quantum system has been predicted to be bounded by $$\lambda _L\le 2\pi \,T/\hbar $$

λ
L

≤
2
π

T
/
ħ

, where T is its temperature, as established by Maldacena, Shenker, and Stanford (MSS). This bound plays an important role in studying very diverse topics of physics, ranging from the dynamics of interacting many-body systems to the black hole information problem, and it is saturated when the system under consideration is the exact holographic dual of a black hole. Based on the fact that an inverted harmonic oscillator (IHO) may exhibit the behavior of thermal energy emission, in close analogy to the Hawking radiation emitted by black holes, we propose using a trapped ion as an implementation of the IHO to verify, in a concrete analogue-gravity system, whether the MSS bound can be identically saturated. To this end, we provide prescriptions for experimentally observing the scattering process at the IHO potential, which yields an analogue of Hawking radiation, as well as for how to measure the corresponding out-of-time-ordered correlation function (OTOC), diagnosing quantum chaos, in this thermally excited semiclassical system. We theoretically show, for an experimentally realizable analogue-gravity setup, that the effective Hawking temperature of the trapped-ion-IHO indeed matches the upper MSS bound for the speed of scrambling.
Mass-derivative relations for leptogenesis
Authors: Blažek Tomáš , Maták Peter
Published: March 2022

In this work, a diagrammatic representation of thermal mass effects is derived from the S-matrix unitarity both in the classical and quantum Boltzmann equations. Within the example of the seesaw type-I leptogenesis, we discuss the connection of the Higgs thermal mass and the cancelations of infrared divergences in zero- and finite-temperature calculations of the right-handed neutrino decay and scattering processes.
Mathematical models of diversification and innovation in biology
Authors: Fuentes Miguel , Ferrada Evandro
Published: March 2022

It is a great pleasure to be part of the celebration of Nitant Kenkre’s scientific career. In this paper, we review mathematical models for studying evolutionary branching and diversification in biology. We highlight insights provided by Nitant Kenkre’s work in the early 2000s as part of the Consortium of the Americas for Interdisciplinary Science. We focus on the use of these models for understanding the conditions that promote phenotypic diversification and innovation in biological systems, understood as the branching of stationary solutions, and some of the ideas that emerged as part of the research Consortium. We highlight recent developments and applications of stochastic, nonlocal partial derivative formalisms.
Analysis and control of axial pressure in high-speed friction stir welding of alloy sheet
Authors: Zhou Yang , Chen Shujin , Chu Longfei , Chen Xinyi
Published: March 2022

Aiming at the high-speed friction stir welding deformation and thickness reduction of 1 mm 6061-T6 aluminum alloy sheet, the characteristics of the axial pressure of the welding process and its influence on the joint structure and mechanical properties were analyzed in this paper. Experiments were performed to optimize process parameters. A fuzzy controller with axial pressure error and its change rate as input and welding speed as output had been designed to realize axial pressure control during friction stir welding. The welding axial pressure fluctuates slightly around the target value, and the system was stable with the controller. Besides, the microstructure of the corresponding weld nugget area was uniform, dense, and the transition area was uniform without obvious welding defects. The joint hardness distribution was stable with the classic “W” shape distribution. The mechanical properties of the joint were excellent, and the tensile strength reaches 195 MPa, which was about 70% of the base material (290 MPa).
Novel Metal Chalcogenide–Conducting Polymer Hybrid Material for Electronic Memory Devices
Authors: Mohammed Kahtan A. , Ziadan Kareema M. , AL-Kabbi Alaa S. , Zabibah Rahman S. , Alrubaie Ali Jawad
Published: March 2022

New hybrid (organic–inorganic) material based on nanocrystalline CdSe capped with EDTA and poly(O-toluidine) doped with camphor sulfonic acid (POT-CSA) is processed from solution and characterized in order to relate the device function (optical absorption, charge separation and transport properties) to active-layer properties and device parameters. POT/CdSe hybrid material has been synthesized using physical mixing method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to investigate the structural and morphological properties. The organic–inorganic composite system was applied as an active device component to demonstrate the electrical memory effects. The device exhibited a nonvolatile, resistive switching performance with a constant ON–OFF current ratio. The nonvolatile behavior was confirmed by applying a 2.5-V read pulse.
Unsupervised Digit Recognition Using Cosine Similarity In A Neuromemristive Competitive Learning System
Authors: Ku Bon Woong , Schuman Catherine D. , Adnan Md Musabbir , Mintz Tiffany M. , Pooser Raphael , Hamilton Kathleen E. , Rose Garrett S. , Lim Sung Kyu
Published: March 2022

This work addresses how to naturally adopt the
l
2
-norm cosine similarity in the neuromemristive system and studies the unsupervised learning performance on handwritten digit image recognition. Proposed architecture is a two-layer fully connected neural network with a hard winner-take-all (WTA) learning module. For input layer, we propose single-spike temporal code that transforms input stimuli into the set of single spikes with different latencies and voltage levels. For a synapse model, we employ a compound memristor where stochastically switching binary-state memristors connected in parallel, which offers a reliable and scalable multi-state solution for synaptic weight storage. Hardware-friendly synaptic adaptation mechanism is proposed to realize spike-timing-dependent plasticity learning. Input spikes are sent out through those memristive synapses to each and every integrate-and-fire neuron in the fully connected output layer, where the hard WTA network motif introduces the competition based on cosine similarity for the given input stimuli. Finally, we present 92.64% accuracy performance on unsupervised digit recognition with only single-epoch MNIST dataset training via high-level simulations, including extensive analysis on the impact of system parameters.
Identifying the Big Shots—A Quantile-Matching Way in the Big Data Context
Authors: Li Guangrui (Kayla) , So Mike K. P. , Tam Kar Yan
Published: March 2022

The prevalence of big data has raised significant epistemological concerns in information systems research. This study addresses two of them—the deflated
p
-value problem and the role of explanation and prediction. To address the deflated
p
-value problem, we propose a multivariate effect size method that uses the log-likelihood ratio test. This method measures the joint effect of all variables used to operationalize one factor, thus overcoming the drawback of the traditional effect size method (θ), which can only be applied at the single variable level. However, because factors can be operationalized as different numbers of variables, direct comparison of multivariate effect size is not possible. A quantile-matching method is proposed to address this issue. This method provides consistent comparison results with the classic quantile method. But it is more flexible and can be applied to scenarios where the quantile method fails. Furthermore, an absolute multivariate effect size statistic is developed to facilitate concluding without comparison. We have tested our method using three different datasets and have found that it can effectively differentiate factors with various effect sizes. We have also compared it with prediction analysis and found consistent results: explanatorily influential factors are usually also predictively influential in a large sample scenario.
A Re-classification of Information Seeking Tasks and Their Computational Solutions
Authors: Tang Zhiwen , Yang Grace Hui
Published: March 2022

This article presents a re-classification of information seeking (IS) tasks, concepts, and algorithms. The proposed taxonomy provides new dimensions to look into information seeking tasks and methods. The new dimensions include number of search iterations, search goal types, and procedures to reach these goals. Differences along these dimensions for the information seeking tasks call for suitable computational solutions. The article then reviews machine learning solutions that match each new category. The article ends with a review of evaluation campaigns for IS systems.
Accuracy and Resiliency of Analog Compute-in-Memory Inference Engines
Authors: Wan Zhe , Wang Tianyi , Zhou Yiming , Iyer Subramanian S. , Roychowdhury Vwani P.
Published: March 2022

Recently, analog compute-in-memory (CIM) architectures based on emerging analog non-volatile memory (NVM) technologies have been explored for deep neural networks (DNNs) to improve scalability, speed, and energy efficiency. Such architectures, however, leverage charge conservation, an operation with infinite resolution, and thus are susceptible to errors. Thus, the inherent stochasticity in any analog NVM used to execute DNNs, will compromise performance. Several reports have demonstrated the use of analog NVM for CIM in a limited scale. It is unclear whether the uncertainties in computations will prohibit large-scale DNNs. To explore this critical issue of scalability, this article first presents a simulation framework to evaluate the feasibility of large-scale DNNs based on CIM architecture and analog NVM. Simulation results show that
DNNs trained for high-precision digital computing engines are not resilient
against the uncertainty of the analog NVM devices. To avoid such catastrophic failures, this article introduces the analog bi-scale representation for the DNN, and the Hessian-aware Stochastic Gradient Descent training algorithm to enhance the inference accuracy of trained DNNs. As a result of such enhancements,
DNNs such as Wide ResNets for CIFAR-100 image recognition problem are demonstrated to have significant performance improvements in accuracy without adding cost to the inference hardware
.
Evidence Transfer: Learning Improved Representations According to External Heterogeneous Task Outcomes
Authors: Davvetas Athanasios , Klampanos Iraklis A. , Skiadopoulos Spiros , Karkaletsis Vangelis
Published: March 2022

Unsupervised representation learning tends to produce generic and reusable latent representations. However, these representations can often miss high-level features or semantic information, since they only observe the implicit properties of the dataset. On the other hand, supervised learning frameworks learn task-oriented latent representations that may not generalise in other tasks or domains. In this article, we introduce evidence transfer, a deep learning method that incorporates the outcomes of external tasks in the unsupervised learning process of an autoencoder. External task outcomes also referred to as categorical evidence, are represented by categorical variables, and are either directly or indirectly related to the primary dataset—in the most straightforward case they are the outcome of another task on the same dataset. Evidence transfer allows the manipulation of generic latent representations in order to include domain or task-specific knowledge that will aid their effectiveness in downstream tasks. Evidence transfer is robust against evidence of low quality and effective when introduced with related, corresponding, or meaningful evidence.
Establishing Data Provenance for Responsible Artificial Intelligence Systems
Authors: Werder Karl , Ramesh Balasubramaniam , Zhang Rongen (Sophia)
Published: March 2022

Data provenance, a record that describes the origins and processing of data, offers new promises in the increasingly important role of artificial intelligence (AI)-based systems in guiding human decision making. To avoid disastrous outcomes that can result from bias-laden AI systems, responsible AI builds on four important characteristics: fairness, accountability, transparency, and explainability. To stimulate further research on data provenance that enables responsible AI, this study outlines existing biases and discusses possible implementations of data provenance to mitigate them. We first review biases stemming from the data's origins and pre-processing. We then discuss the current state of practice, the challenges it presents, and corresponding recommendations to address them. We present a summary highlighting how our recommendations can help establish data provenance and thereby mitigate biases stemming from the data's origins and pre-processing to realize responsible AI-based systems. We conclude with a research agenda suggesting further research avenues.
How Cross-Link Numbers Shape the Large-Scale Physics of Cytoskeletal Materials
Authors: Fürthauer Sebastian , Shelley Michael J.
Published: March 2022

Cytoskeletal networks are the main actuators of cellular mechanics, and a foundational example for active matter physics. In cytoskeletal networks, motion is generated on small scales by filaments that push and pull on each other via molecular-scale motors. These local actuations give rise to large-scale stresses and motion. To understand how microscopic processes can give rise to self-organized behavior on larger scales it is important to consider what mechanisms mediate long-ranged mechanical interactions in the systems. Two scenarios have been considered in the recent literature. The first scenario is systems that are relatively sparse, in which most of the large-scale momentum transfer is mediated by the solvent in which cytoskeletal filaments are suspended. The second scenario is systems in which filaments are coupled via cross-link molecules throughout. Here, we review the differences and commonalities between the physics of these two regimes. We also survey the literature for the numbers that allow us to place a material within either of these two classes.
Preparation and Gas Sensing Properties of rGO/CuO Nanocomposites
Authors: Quang Dat Do , Van Nang Lam , Hung Chu Manh , Thi Xuan Chu , Van Duy Nguyen , Hoa Nguyen Duc
Published: March 2022

Gas sensors are instrumental in the control and monitoring of air pollution. A facile fabrication method for low-cost gas sensors with high sensitivity and a fast response time is crucial in practical applications. Here, reduced graphene oxide (rGO)–CuO nanocomposites were synthesized for gas-sensing applications using a facile hydrothermal method. The crystal structure, surface morphology, and electrical properties of the nanocomposites were inferred from X-ray powder diffraction patterns, scanning electron microscopic images, and current–voltage (I–V) measurements, respectively. The results confirmed a high-quality rGO–CuO material with a spherical flower-like morphology. The CuO material showed a single-phase monoclinic crystal structure with an average crystal size of ∼21 nm. Within the composite, high-quality rGO was incorporated into the porous spherical flower-like CuO material. In gas-sensing measurements, the rGO–CuO nanocomposite detected NO2 gas at low concentrations (1–5 ppm) with reasonably high response values and a fast response time (<1 min). An rGO–CuO nanocomposite-based sensor was fabricated, showing good repeatability for practical applications.
Fabrication and Characterization of AA6063/B4C Metal Matrix Surface Nanocomposite Using Friction Stir Processing
Authors: Pratap Chandra , Chandra Prakash , Butola Ravi , Shukla Anurag
Published: March 2022

In development of nanocomposite the aims of the present work is to formation of Self-assembled monolayer (SAM) of boron carbide over the surface of AA6063 using via Friction stir processing (FSP). Boron Carbide nano-particle is bonded over the surface of AA6063 followed by FSP technique. To ensure uniform distribution of nanoparticle reinforcement in the grooves a 0.5 molar solution was prepared by dissolving 0.138 g of B4C in 5 ml of diethyl ether (DEE) with enhanced surface and mechanical properties. Two passes on both specimens were performed using the same tool with the tool rotational and traverse speed as 1000 rpm and 40 mm s−1 respectively. For minimizing defects a square tool pin profile with pin length of 3.5 mm and 7.2 mm diagonal. The resultant specimens are studied for the significant changes in tensile strength, ductility, hardness and wear properties due to the addition of reinforcement material and refinement of grain structure. The microstructural graphs supported by SEM and EDS analysis were focused upon to study the composition of nanocomposite prepared. The nanocomposite and FSPed specimen showed an increase in hardness by more than two folds with a negligible decrease in ductility and an appreciable improvement in wear resistance.
Increased airway liquid volumes at birth impair cardiorespiratory function in preterm and near-term lambs
Authors: Yamaoka Shigeo , Crossley Kelly J. , McDougall Annie R. A. , Rodgers Karyn , Zahra Valerie A. , Moxham Alison , Te Pas Arjan B. , McGillick Erin V. , Hooper Stuart B.
Published: March 2022

We provide evidence for adverse effects of elevated airway liquid volumes at birth on pulmonary blood flow and gas exchange in both preterm and near-term lambs, although the effects were greatest in near-term newborns. Our study is an important step toward understanding the fundamental physiology underlying the cardiorespiratory morbidity associated with near-term newborns with elevated airway liquid volumes leading to respiratory distress soon after birth.
Structural Covariance of the Ipsilesional Primary Motor Cortex in Subcortical Stroke Patients with Motor Deficits
Authors: Chen Xinyuan , Li Mengcheng , Chen Naping , Lai Huimin , Huang Ziqiang , Tu Yuqing , Chen Qunlin , Hu Jianping
Published: March 2022

The analysis of structural covariance has emerged as a powerful tool to explore the morphometric correlations among broadly distributed brain regions. However, little is known about the interactions between the damaged primary motor cortex (M1) and other brain regions in stroke patients with motor deficits. This study is aimed at investigating the structural covariance pattern of the ipsilesional M1 in chronic subcortical stroke patients with motor deficits. High-resolution T1-weighted brain images were acquired from 58 chronic subcortical stroke patients with motor deficits (29 with left-sided lesions and 29 with right-sided lesions) and 50 healthy controls. Structural covariance patterns were identified by a seed-based structural covariance method based on gray matter (GM) volume. Group comparisons between stroke patients (left-sided or right-sided groups) and healthy controls were determined by a permutation test. The association between alterations in the regional GM volume and motor recovery after stroke was investigated by a multivariate regression approach. Structural covariance analysis revealed an extensive increase in the structural interactions between the ipsilesional M1 and other brain regions in stroke patients, involving not only motor-related brain regions but also non-motor-related brain regions. We also identified a slightly different pattern of structural covariance between the left-sided stroke group and the right-sided stroke group, thus indicating a lesion-side effect of cortical reorganization after stroke. Moreover, alterations in the GM volume of structural covariance brain regions were significantly correlated to the motor function scores in stroke patients. These findings indicated that the structural covariance patterns of the ipsilesional M1 in chronic subcortical stroke patients were induced by motor-related plasticity. Our findings may help us to better understand the neurobiological mechanisms of motor impairment and recovery in patients with subcortical stroke from different perspectives.