bluuebunny/crossref_metadata_2025_split huggingface dataset:
How much should we be concerned about cumulative effective doses in medical imaging?
Authors: Martin Colin J , Barnard Michael 
Published: October 2021

Abstract
The International Atomic Energy Agency issued a statement calling for action to strengthen the radiation protection of patients undergoing recurrent imaging. This followed reports of patients receiving cumulative effective doses over 100 mSv from multiple computed tomography examinations. In order to evaluate excess risks of cancer incidence among UK patients, data from an exposure management system covering three hospitals within one trust have been studied over 5½ years. Cumulative effective doses for 105 757 patients, from whom 719 (0.68%) received effective dose over 100 mSv, have been analysed using age and sex specific risk factors for stochastic effects. Two cancers might be expected to be initiated in the patients receiving over 100 mSv, while five might be expected to develop cancer among patients receiving 50–100 mSv. However, the calculations ignore health conditions for which the patients are being treated that may shorten their lives, and rely on the linear-no-threshold dose-effect model which is a subject of debate, so they are likely to overestimate cancer incidence. If health of the patients receiving >100 mSv is taken into account, the risk of mortality from cancer initiated by medical exposure might be the order of 1 in 2000. Recommendations on further strengthening of optimisation should be applied to imaging procedures for all patients with special focus on those performed on children and adolescents.
94 GHz microplasma sustained by a photonic crystal
Authors: Hopwood Jeffrey 
Published: October 2021

Abstract
A photonic crystal (PhC) with a single vacancy sustains an argon microplasma at 94 GHz. The PhC consists of a 7 × 13 array of small alumina rods, each 250 μm in radius. The PhC has a forbidden bandgap from 70–105 GHz. The vacancy creates an internal electromagnetic resonance at 94 GHz that intensifies the electric field of an incident wave to 5 × 105 V m−1. Breakdown of low-pressure argon gas (80 mbar) occurs and forms a stable, ellipsoidal plasma inside the crystal. The central core of the microplasma is probed using a 200 μm optical fiber inserted into the PhC. The rotational temperature of the CH molecule is estimated from a numerical fit of the plasma emission and is found to increase from 450–650 K with both pressure (200–1000 mbar) and incident wave power (100 mW–1100 mW). Under these conditions, the electron density increases with both power and pressure from 0.5–1.5 × 1020 m−3. This plasma density range brackets the electron plasma frequency at 94 GHz. The results are compared with a similar microplasma operating at 44 GHz.
Underlying mechanism of the stagnation of positive streamers
Authors: Niknezhad M , Chanrion O , Holbøll J , Neubert T 
Published: October 2021

Abstract
Several publications have shown that it is challenging to model the stagnation of positive streamers. They find that as the streamers propagate, the space charge region at the streamer tip reduces in size and that the associated electric field increases towards infinity. In a recent study on streamer propagation in unsteady airflow, we circumvented this problem by relaxing the local density and electric field approximation in the drift-diffusion model, commonly used in the past models. The results, recently published, show that the electric field remains bounded during the streamer propagation. In the present paper, we explore the process of stagnation further with a more rigorous approach. We confirm that the instability in the electric field is an immediate effect of the local density and field approximation and that an extended description of ionization stabilizes the electric field and leads to a decelerating streamer. Finally, we discuss the role of positive ions in the stagnation and we show that the stagnating streamer velocity decreases till it becomes comparable to the ion velocities in the streamer head. This causes a broadening of the streamer head which leads to a sharp decrease in the streamer tip electric field and the streamer stagnation.
A SiC gate turn-off thyristor with high di/dt for fast switching-on applications
Authors: Li Zhiqiang , Zhang Lin , Li Lianghui , Xu Xingliang , Tao Hong , Meng Yinghao , Zhou Kun , Li Juntao 
Published: October 2021

Abstract
High di/dt 4H-silicon carbide (SiC) gate turn-off thyristors (GTOs) are investigated and developed for fast switching-on application. This work has focused on accelerating the turn-on process to improve the di/dt characteristic, and the n-base dopant concentration is carefully designed to increase the injection efficiency of top P+N junction. With reducing n-base dopant concentration from 2.3 × 1017cm−3 to 6.8 × 1016cm−3, the injection efficiency is increased about 18%, and consequently the current rise-up process and subsequent lateral propagation of the anode current are obviously accelerated. Experimental results show that the di/dt capability is greatly improved and a high di/dt of 126 kA cm−2
μs−1 is obtained. The excellent di/dt performance makes the designed 4H-SiC GTO a promising candidate for fast switching-on application.
Motion parallax for object localization in electric fields
Authors: Hunke Kevin , Engelmann Jacob , Meyer Hanno Gerd , Schneider Axel 
Published: October 2021

Abstract
Parallax, as a visual effect, is used for depth perception of objects. But is there also the effect of parallax in the context of electric field imagery? In this work, the example of weakly electric fish is used to investigate how the self-generated electric field that these fish utilize for orientation and communication alike, may be used as a template to define electric parallax. The skin of the electric fish possesses a vast amount of electroreceptors that detect the self-emitted dipole-like electric field. In this work, the weakly electric fish is abstracted as an electric dipole with a sensor line in between the two emitters. With an analytical description of the object distortion for a uniform electric field, the distortion in a dipole-like field is simplified and simulated. On the basis of this simulation, the parallax effect could be demonstrated in electric field images i.e. by closer inspection of voltage profiles on the sensor line. Therefore, electric parallax can be defined as the relative movement of a signal feature of the voltage profile (here, the maximum or peak of the voltage profile) that travels along the sensor line peak trace (PT). The PT width correlates with the object’s vertical distance to the sensor line, as close objects create a large PT and distant objects a small PT, comparable with the effect of visual motion parallax.
Multimode

-symmetry thresholds and third-order exceptional points in coupled dielectric waveguides with loss and gain
Authors: Hlushchenko Anton V , Novitsky Denis V , Shcherbinin Vitalii I , Tuz Vladimir R 
Published: October 2021

Abstract
A pair of coupled dielectric waveguides with balanced loss and gain is the basic system for observing the phenomena of parity-time (

) symmetry and exceptional points (EPs). We use the multimode analytical approach to study the peculiarities of interaction between the modes excited in such an archetypal structure. With this approach, the conditions for

symmetry breaking are obtained in the special case of the hybrid HE and EH modes resulting in the ordinary second-order EPs (or

-symmetry thresholds). The coupling of modes with the different azimuthal indices (the TM01 and HE21 modes in our study) generates the uncommon types of EPs. First, there are the so-called multimode

-symmetry thresholds due to interaction of hybrid and transverse modes. Second, the third-order EPs appear as a result of three-modes degeneracy of real eigenvalues. It is noteworthy that an increase in the EPs order is achieved without both breaking the

symmetry and introducing additional elements into the waveguide structure. The results obtained with the multimode analytical approach are in perfect agreement with the independent full-wave simulations.
Wireless to optical phase mapping in a seamless digital wireless-photonic link
Authors: Ghosh Niloy , Pendharker Sarang 
Published: October 2021

Abstract
This paper shows that mapping of phase levels of a digitally modulated wireless signal from the mmWave domain to the equivalent optical domain is inherently a non-linear phenomenon in Pockel’s effect-based seamless digital mmWave-to-photonic converters. We report several novel implications of seamless phase mapping, crucial for the realization of seamless wireless-to-photonic links. The latency and design complexity of such converters are expected to be appreciably lower than conventional converters. The results on seamless phase mapping presented in this paper are scalable with the wireless frequency of operation.
Transcriptomic profiling of neonatal mouse granulosa cells reveals new insights into primordial follicle activation
Authors: Ford Emmalee A , Frost Emily R , Beckett Emma L , Roman Shaun D , McLaughlin Eileen A , Sutherland Jessie M 
Published: October 2021

Abstract
The dormant population of ovarian primordial follicles is determined at birth and serves as the reservoir for future female fertility. Yet our understanding of the molecular, biochemical, and cellular processes underpinning primordial follicle activation remains limited. The survival of primordial follicles relies on the correct complement and morphology of granulosa cells, which provide signaling factors essential for oocyte and follicular survival. To investigate the contribution of granulosa cells in the primordial-to-primary follicle transition, gene expression profiles of granulosa cells undergoing early differentiation were assessed in a murine model. Ovaries from C57Bl/6 mice were enzymatically dissociated at time-points spanning the initial wave of primordial follicle activation. Post-natal day (PND) 1 ovaries yielded primordial granulosa cells, and PND4 ovaries yielded a mixed population of primordial and primary granulosa cells. The comparative transcriptome of granulosa cells at these time-points was generated via Illumina NextSeq 500 system, which identified 131 significantly differentially expressed transcripts. The differential expression of eight of the transcripts was confirmed by RT-qPCR. Following biological network mapping via Ingenuity Pathway Analysis, the functional expression of the protein products of three of the differentially expressed genes, namely FRZB, POD1, and ZFX, was investigated with in-situ immunolocalization in PND4 mouse ovaries was investigated. Finally, evidence was provided that Wnt pathway antagonist, secreted frizzled-related protein 3 (FRZB), interacts with a suppressor of primordial follicle activation WNT3A and may be involved in promoting primordial follicle activation. This study highlights the dynamic changes in gene expression of granulosa cells during primordial follicle activation and provides evidence for a renewed focus into the Wnt signaling pathway’s role in primordial follicle activation.
Evaluation of different late left ventricular remodeling definitions for predicting long-term outcomes in acute myocardial infarction patients undergoing percutaneous coronary intervention
Authors: Zhang S , Xie X , He C , Lin X , Luo M , Lin M , Fang M , You Z , Lin K , Guo Y 
Published: October 2021

Abstract

Background
Late left ventricular remodeling (LLVR) after the index acute myocardial infarction (AMI) is a common complication, and is associated with poor outcome. However, the optimal definition of LLVR has been debated because of its different incidence and influence on prognosis. At present, there are limited data regarding the influence of different LLVR definitions on long-term outcomes in AMI patients undergoing percutaneous coronary intervention (PCI).

Purpose
To explore the impact of different definitions of LLVR on long-term mortality, re-hospitalization or an urgent visit for heart failure, and identify which definition was more suitable for predicting long-term outcomes in AMI patients undergoing PCI.

Methods
We prospectively observed 460 consenting first-time AMI patients undergoing PCI from January 2012 to December 2018. LLVR was defined as a ≥20% increase in left ventricular end-diastolic volume (LVEDV), or a &gt;15% increase in left ventricular end-systolic volume (LVESV) from the initial presentation to the 3–12 months follow-up, or left ventricular ejection fraction (LVEF) &lt;50% at follow up. These parameters of the cardiac structure and function were measuring through the thoracic echocardiography. The association of LLVR with long-term prognosis was investigated by Cox regression analysis.

Results
The incidence rate of LLVR was 38.1% (n=171). The occurrence of LLVR according to LVESV, LVEDV and LVEF definition were 26.6% (n=117), 31.9% (n=142) and 11.5% (n=51), respectively. During a median follow-up of 2 years, after adjusting other potential risk factors, multivariable Cox regression analysis revealed LLVR of LVESV definition [hazard ratio (HR): 2.50, 95% confidence interval (CI): 1.19–5.22, P=0.015], LLVR of LVEF definition (HR: 16.46, 95% CI: 6.96–38.92, P&lt;0.001) and LLVR of Mix definition (HR: 5.86, 95% CI: 2.45–14.04, P&lt;0.001) were risk factors for long-term mortality, re-hospitalization or an urgent visit for heart failure. But only LLVR of LVEF definition was a risk predictor for long-term mortality (HR: 6.84, 95% CI: 1.98–23.65, P=0.002).

Conclusions
LLVR defined by LVESV or LVEF may be more suitable for predicting long-term mortality, re-hospitalization or an urgent visit for heart failure in AMI patients undergoing PCI. However, only LLVR defined by LVEF could be used for predicting long-term mortality.

Funding Acknowledgement
Type of funding sources: None. Association Between LLVR and outcomesKaplan-Meier Estimates of the Mortality
Diagnostic and prognostic role of peak troponin T in patients with acute coronary syndromes and non-obstructive coronary arteries
Authors: Williams M G L , Liang K , De Garate E , Spagnoli L , Fiori E , Lawton C B , Dastidar A , Johnson T W , Biglino G , Bucciarelli-Ducci C 
Published: October 2021

Abstract

Background
Up to 10% of patients who present with an acute coronary syndrome have a myocardial infarction with non-obstructive coronary arteries (MINOCA). Troponin T predicts infarct size and outcomes in patients with ST-elevation myocardial infarction. The value of peak troponin T in patients with a working diagnosis of MINOCA is not well understood.

Purpose
The aim of this study is to investigate the diagnostic and prognostic role of troponin in patients with MINOCA.

Methods
Consecutive patients with a working diagnosis of MINOCA from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. Peak troponin T was identified during the index admission and divided into deciles and quartiles for analysis. The primary endpoint was all-cause mortality.

Results
Among 796 patients undergoing CMR, 719 met the study criteria and had underwent a diagnostic quality scan. The peak Troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Peak troponin T ≥211 ng/L and time to CMR of ≤14 days has a sensitivity of 94%, specificity of 35%, PPV 57% and NPV 94% for the CMR making a diagnosis. Each increase in troponin decile increases the mean diagnostic yield of the CMR by 3.65% (p&lt;0.001, 95% CI 3.38 – 3.91; R2 0.84; Figure 1).
If the troponin is in the lowest decile and the CMR is performed at ≤14 days, the diagnostic yield is still 72%. There is no overall difference in median troponin in patients who died and those who survived (229 ng/l v. 424 ng/l; p=0.157), however mortality is significantly lower in the highest two troponin quartiles (6.9% versus 11.9%; p=0.009; Figure 2).

Conclusion
Peak troponin T is readily available during the index admission in patients presenting with MINOCA and provides useful diagnostic and prognostic information for the attending cardiologist.

Funding Acknowledgement
Type of funding sources: None. Figure 1. CMR diagnosis by troponin decileFigure 2. Mortality by troponin quartile
Cardiac output monitoring using transthoracic echocardiography in children after cardiac surgery-an observational study of feasibility and concordance with transpulmonary thermodilution
Authors: Guha Niyogi S , Kumar B , Puri G D , Negi S , Mishra A K , Thingnam S K S 
Published: October 2021

Abstract

Background
Transthoracic echocardiography (TTE) is commonly used after pediatric cardiac surgery to monitor cardiac function and adequacy of surgery; however it depends on the availability of good echo window and operator skill [1]. Transpulmonary thermodilution (TPTD) is feasible along with calibrated continuous cardiac output measurement in children but seldom used due to cost and the need for a specialized catheter [2].
We hypothesized that TTE would be as good as TPTD, but limited in feasibility following pediatric cardiac surgery. Hence, the concordance, agreement as well as feasibility and trending of cardiac output monitoring by TTE was compared against a reference TPTD method in real-world usage in children after congenital heart surgery.

Methods
This was a secondary analysis of data from a previously registered and conducted study in our unit. TPTD monitoring was instituted in children undergoing congenital heart disease repair on cardiopulmonary bypass with a 3F femoral arterial cannula and a central venous injectate temperature sensor.
Cardiac output was also measured by transthoracic echocardiography by measurement of the left ventricular outflow tract (LVOT) diameter, LVOT velocity time integral (VTI) and the heart rate as previously described [3,4]. Measurements were taken after arrival in the ICU, and every 12 hours till after extubation. Correlation, Bland-Altman analysis and polar analysis was done for cardiac output measured by TPTD and TTE.

Results
TTE and TPTD measurements of cardiac output correlated well (Pearson's correlation coefficient 0.94; 95% CI 0.90–0.96) (Fig. 1A). Bland Altman analysis showed a mean bias of 0.15 l/min and upper and lower limits of agreement of 0.81 and −0.51 l/min respectively (Fig. 1B). Cardiac output measurement by TTE was possible in 72 instances while TPTD allowed measurement in all 113 instances. Hence, TTE was not feasible in 41 instances across 14 patients, including 19 instances in acyanotic and 22 instances in cyanotic patients. Polar analysis revealed acceptable trending.

Conclusions
TTE derived cardiac output demonstrated good correlation, minimal bias and narrow limits of agreement versus TPTD, and was feasible in most cases. This suggests TTE is an acceptable cardiac output measurement modality post pediatric cardiac surgery, as in adults [5]. TPTD-based continuous cardiac output monitoring might have a complementary role in pediatric cardiac critical care, particularly in high risk cases.

Funding Acknowledgement
Type of funding sources: Public Institution(s). Main funding source(s): Institutional Special Research Grant from Postgraduate Institute of Medical Education and Research, Chandigarh, India. Figure 1
Impact of high cardiovascular risk on hospital mortality in patients admitted to intensive care by COVID-19
Authors: Gomes B F O , Silva T M B , Dutra G P , Azevedo A S , Pereira D F P , Peres L S , Nascimento J H P , Petriz J L F , Carmo Junior P R , Pereira B B , Oliveira G M M 
Published: October 2021

Abstract

Background
Some studies have shown a higher prevalence of deaths in patients with cardiovascular risk factors (CRF) during hospitalization for COVID-19. The impact of high cardiovascular risk on hospital mortality has not been evaluated.

Methods
Retrospective study with patients admitted to intensive care and confirmed diagnosis of COVID-19 by RT-PCR and with at least one measurement of troponin during hospitalization. The criteria for defining a high cardiovascular risk patient (HCR) were: history of established cardiovascular disease (myocardial infarction, stroke, or peripheral arterial disease), diabetes, chronic kidney disease with clearance &lt;60ml/min, or presence of, at least, 3 risk factors (hypertension, smoking, dyslipidemia or age&gt;65 years). The population was divided into 4 groups according to the presence of HCR and elevated troponin. Mortality was assessed using the chi-square method, according to the number of CRF, and was assessed in the 4 predetermined groups through logistic regression adjusted for severity (using the SAPS3 score).

Results
After evaluating 271 admissions during the study period, 236 patients were included for analysis. The mean age was 61.14±16.2 years, with 63.1% men. The prevalence of hypertension was 55.5% and diabetes, 33.1%. 47.4% of the patients had HCR. There was a significant increase in mortality as the number of risk factors increased (no CRF: 5.9%; 1 CRF: 17.5%; 2 CRF: 32.2% and ≥3 CRF: 41.2%; p=0.001). In logistic regression, patients with high cardiovascular risk and high troponin had a higher incidence of hospital mortality (OR 40.38; 95% CI 11.78–138.39). Patients without high cardiovascular risk, but with high troponin also showed a significant association with the primary outcome (OR 16.7; 95% CI 4.45–62.74). In contrast, patients with high cardiovascular risk and normal troponin were not at higher risk of death (OR 2.06; 95% CI 0.56–7.56).

Conclusion
In patients admitted to intensive care by COVID-19, the high cardiovascular risk impacts on hospital mortality only in patients who presented an increase in troponin levels.

Funding Acknowledgement
Type of funding sources: None.
Increased risk of non-hematological cancer in young patients with aortic stenosis: a retrospective cohort study
Authors: Shiran A , Bental T , Shapira Y , Schwartzenberg S , Sagie A , Vaturi M , Adawi S , Fuks A , Aronheim A , Saliba W 
Published: October 2021

Abstract

Background
We have previously reported an increased risk for non-hematological malignancies in young patients with moderate or severe aortic stenosis (AS) (1). These findings were the result of a post-hoc analysis from a large echocardiography database and needed verification.

Purpose
To determine, using a different study population, whether young patients with AS are at increased risk for cancer.

Methods
A large echocardiographic database was used to identify patients (age≥20 years) with moderate or severe AS (study group) and patients without aortic stenosis (comparative group). The new occurrence of non-hematological malignancies was determined after the index date (first echo with moderate or severe AS or first recorded echo in the control group).

Results
The final study group included 7,013 patients with AS and 98,884 without AS. During a median follow-up of 6.9 years (3.0–11.1) there were 10,705 new cases of non-hematological cancer. The crude incidence rate of cancer was higher in AS compared to non-AS patients (22.3 vs. 13.7 per 1,000 patient-year, crude HR 1.58 (95% CI 1.46–1.71). After adjustment for relevant covariates, there was no difference between groups (HR 0.93, 95% CI 0.86–1.01). Only patients in the lowest age quartile (20–49.7 years), had an increased adjusted risk of cancer (HR 1.91, 95% CI 1.08–3.39). The HR for the risk of cancer in AS was inversely proportional to age (P&lt;0.001 for the interaction between AS and age) (Figure 1).

Conclusion
Young patients with moderate or severe AS are at increased risk for cancer. Cancer surveillance should be considered for young patients with AS.

Funding Acknowledgement
Type of funding sources: None. Figure 1