Contour Analysis Research Articles

Photoplethysmography in assessment of skin microcirculation in pregnant women with gestational arterial hypertension

Introduction. One of the urgent problems of modern obstetrics is gestational arterial hypertension (GAH), which entails a whole range of complications for both mother and fetus. In this regard, it is necessary to search for economically accessible, informative and safe methods for early diagnosis of uteroplacental blood flow disorders in pregnant women.The aim of the study was to investigate the features of peripheral and uteroplacental blood flow in pregnant women with GAH, to assess the state of the vascular wall of pregnant women using photoplethysmography and to determine its association with uteroplacental blood flow disorders. Materials and methods. A total of 78 patients with 22 to 40 weeks of pregnancy, divided into two groups, were clinically examined: the first group (n=42) were pregnant women with GAH, the second group the control group (n=36) consisted of patients with physiological course of gestation. The study included assessment of the objective clinical status of the pregnant woman, recording and contour analysis of photoplethysmograms, ultrasound examination of the uteroplacental and fetoplacental blood flow, and statistical processing of the results.Results. When comparing the anthropometric characteristics of the studied groups, an increase in BMI was found in the group of pregnant women with GAG (p<0.05). Contour analysis of photoplethysmography (PPG) data showed an increase in the augmentation index in pregnant women with GAG by 73.47 % (p=0.054), an increase in central arterial pressure by 3.6 % (p<0.05). Changes in peripheral hemodynamics in pregnant women with hypertensive disorder were associated with impaired fetoplacental blood flow (rxy = 0.52-0.86, p < 0.05), which was accompanied by lower fetal biometry parameters (p<0.05).Conclusion. Hemodynamic disturbances in the mother-placenta-fetus system correlate with changes in the parameters of peripheral circulation, which allows us to consider the additional use of the photoplethysmography method as promising in terms of early diagnostics and prevention of perinatal complications in mother and fetus.

Comparison of clinical results between transpulmonary thermodilution monitoring and conventional methods in cardiac surgery: An observational study.

The Pulse Index Contour Continuous Cardiac Output (PICCO) module provides advanced and continuous monitoring of cardiac output through the use of arterial pulse contour analysis and transpulmonary thermodilution. The objective of this study was to compare the early postoperative outcomes of patients who were monitored using the conventional method and the pulse contour analysis method. A prospective observational study was conducted involving 45 patients who underwent cardiac surgery between 2020 and 2022. Patients were randomly assigned to either Group P (PICCO) or Group C (conventional). In the PICCO cohort, a femoral artery cannula was inserted for the continuous recording and management of hemodynamic data, in accordance with the decision-making algorithm of the module. In the conventional group, cannulation of the radial artery and jugular vein was performed. The postoperative hemodynamic and clinical data are subjected to analysis. The utilization of dopamine was markedly diminished in Group P at both the 0- and 6-hour postoperative intervals, whereas the administration of dobutamine was observed to be elevated (P = .008). The frequency of red packed cell transfusions was higher in Group C at postoperative hour 0. Hemodynamic data indicated a 42% increase in cardiac index and a 33% decrease in systemic vascular resistance, along with a 33% increase in global ejection fraction in patients monitored with PICCO. The mortality rates observed in the 2 groups were not statistically different. The implementation of advanced monitoring techniques, specifically the PICCO module, led to notable enhancements in hemodynamic parameters. The utilization of this technique may prove advantageous in guiding inotrope selection and transfusion decisions during the initial postoperative period. However, it is important to note that morbidity and mortality rates remain comparable.

Критический анализ гипотетических представлений о постчеловечестве в трансгуманизме и постгуманизме

The idea of posthuman future as an inevitable prospect is being actively postulated by the theorists of transhumanism and posthumanism. The article makes an attempt to identify the key ideas and essential characteristics of hypothetical posthumanity as it is presented in transhumanistic and posthumanistic readings. Against the background of the active development and use of bio- and nanotechnologies, entailing the practice of technological invasion of human biological nature, and postulating the idea about the need to overcome the anthropological boundary between the human and non-human worlds, the topic of posthumanity becomes an integral part of philosophical and anthropological discourse. The author of the article performed a comparative analysis of the conceptual contours of transhumanism and posthumanism. Posthumanism is based on the idea of inclusiveness that refutes the exclusive role of man. It deprives humans of the privileged ethical and ontological status, placing them on par with nonhuman creatures, technologies and objects. Transhumanism pursues the same ultimate goal as posthumanism: the achievement of posthumanity. Transhumanism, aimed at improving human nature with the help of scientific and technical means outside the context of moral principles, reduces a person to an object of uncontrolled technical manipulations. In transhumanism and posthumanism, two hypothetical models (forms of existence) of а non-human future can be singled out: technologically modified and hybrid. Both models are characterized by the destruction of the fundamental anthropological constants, blurring the boundaries between the human and the non-human. The posthuman world in transhumanistic and posthumanistic projections has no connection to the issues of morality, free will, spiritual or moral values. Rejecting the human world, proponents of transhumanism and posthumanism offer prospects of non-human civilization with unpredictable axiological orientations.

Machine learning-driven image synthesis and analysis applications for inertial confinement fusion (invited).

Recent fusion breakeven [Abu-Shawareb etal., Phys. Rev. Lett. 132, 065102 (2024)] in the National Ignition Facility (NIF) motivates an integrated approach to data analysis from multiple diagnostics. Deep neural networks provide a seamless framework for multi-modal data fusion, automated data analysis, optimization, and uncertainty quantification [Wang etal., arXiv:2401.08390 (2024)]. Here, we summarize different neural network methods for x-ray and neutron imaging data from NIF. To compensate for the small experimental datasets, both model based physics-informed synthetic data generation and deep neural network methods, such as generative adversarial networks, have been successfully implemented to allow a variety of automated workflows in x-ray and neutron image processing. We highlight results in noise emulation, contour analysis for low-mode analysis and asymmetry, denoising, and super-resolution. Further advances in the integrated multi-modal imaging, in sync with experimental validation and uncertainty quantification, will help with the ongoing experimental optimization in NIF, as well as the maturation of alternate inertial confinement fusion (ICF) platforms such as double-shells.

Analysis of Factors Affecting the Import and Export of New Energy Products

With global warming and climate change becoming more and more serious, countries around the world have begun to pay attention to emission reduction and environmental protection, and the concept of ‘dual carbon’ has further penetrated into people's hearts, bringing new opportunities for the export of power lithium batteries from China. This paper aims to conduct a digital analysis of the export trade of the top seven countries (regions) in terms of the volume of power lithium battery trade in China, and to explore the influencing factors of the export volume of power lithium batteries from China. This paper first conducts a contour analysis based on the data fluctuations of five indicators in 32 provinces (excluding Hong Kong, Macao and Taiwan) from 2019 to 2021: total carbon dioxide emissions (mt), lithium iron phosphate production (10,000 tons), lithium battery electrolyte (10,000 tons), two-wheeled electric vehicles (100,000 vehicles), and lithium battery separators (10,000 tons). The final conclusion is that the ‘dual carbon’ background has a significant impact on China's power lithium battery industry. Furthermore, based on a panel data regression model, the factors affecting trade between China and the major countries (regions) exporting power lithium batteries are explored in depth. The results of the analysis found that the power generation, economic freedom, number of charging piles, population size, and per capita GDP of the exporting countries significantly affect the export volume of power lithium batteries in China. Among them, the population size and per capita GDP growth rate of the exporting countries have a negative impact, while the rest have a positive impact on the export volume of power lithium batteries in China.

Perception and Production of Pitch Information in Mandarin-Speaking Children with Autism Spectrum Disorders.

This study investigated the categorical perception (CP) of linguistic pitch (lexical tones) and nonlinguistic pitch (pure tones), as well as tonal production in Mandarin-speaking children with autism spectrum disorders (ASD). A total of 26 Mandarin-speaking children with ASD and 29 age-matched typically developing (TD) children were recruited for this study. The Mandarin T2-T3 contrast and corresponding pure tones with identical pitch contours were adopted to assess the nuanced pitch processing abilities of the child participants via the CP paradigm. Accordingly, tonal production was focused on T2 and T3 with analyses of the dynamic pitch contours and tonal differentiation. Mandarin-speaking children with ASD exhibited atypical CP for linguistic pitch in comparison with their TD peers. However, the categorization of linguistic pitch exceeded that of nonlinguistic pitch among the ASD participants, indicating a global over local processing pattern contrary to autistic individuals in non-tonal languages. Additionally, despite atypical pitch contours in producing T2 and T3, the ASD group showed comparable differentiable degrees of the two tones in production to the TD group. Findings of this study served as a foray into contesting current theories' claims of local bias and/or global impairment in the autistic population, prompting further inspections on individuals with different language backgrounds and stimuli processing with various complexities. Additionally, findings of this study underscore the necessity of developing tailored assessments and interventions to enhance the perception and production of complex and confusable tones, thereby improving perceptual robustness and communication skills in Mandarin-speaking children with ASD.

Impact of extract of cryopreserved pig heart fragments in alginate hydrogel on electrophysiological indicators of rat hearts with myocardial cryonecrosis

Background. The issue of stimulating reparative myocardial regeneration in ischemic heart disease (IHD) is a pressing one, requiring in-depth experimental and clinical research. Consequently, considerable attention is currently being paid to studies on the effectiveness and mechanisms of action of regenerative plastic therapy for pathological conditions of the cardiovascular system. To prevent cardiac aneurysms in the early post-infarction period and to treat progressive chronic heart failure, biodegradable polymer hydrogels, including alginate polysaccharide hydrogels, are used as surgical implants. Purpose – analysis of electrophysiological indicators of the heart during the development of necrosis and organ remodeling in a myocardial cryodestruction model and the introduction of an alginate implant saturated with an extract of cryopreserved pig heart fragments to determine the cardioprotective effect of these factors. Materials and Methods. Electrocardiograms (ECGs) were recorded in three standard leads (I, II, III) and three additional leads (aVR, aVL, aVF) using the «PolySpectrum/8V» hardware-software complex («Poly-Spectrum», Ukraine). The «PolySpectrum-Analysis» software allows for contour analysis of the averaged cardiocomplex. Initially, we conducted an experiment to assess the impact of sodium alginate hydrogel alone on electrocardiographic parameters without heart cryoinjury. Subsequently, the experimental animals were divided into three groups: 1 – control group, animals with myocardial necrosis (MN) without treatment; 2 – rats with MN and an implant (sodium alginate hydrogel) introduced into the cryonecrosis area; 3 – rats with MN and an alginate implant saturated with cryopreserved pig heart extract (CPHE) introduced into the cryonecrosis area. The normal group consisted of 7 rats. Results. The use of an extract from cryopreserved heart fragments of piglets, delivered via an alginate carrier, in the context of myocardial infarction induced by local cryodestruction of the heart, significantly accelerates the recovery of the left ventricular myocardium compared to both the control group and the experimental groups receiving alginate hydrogel alone. This is supported by electrocardiographic evidence: a positive P wave on the first day indicates the preservation of the myocardial excitation source at the sinoatrial node level; recovery of the R wave to normal levels by the seventh day reflects the restoration of myocardial contractile function; and on the 30th day, the group treated with the ECP in alginate gel shows a QRS complex shape that conforms to normal standards, with minimal cardiac remodeling as evidenced by the absence of a Q wave in the ECG. In contrast, up to 40% of animals in other groups exhibit signs of transmural myocardial necrosis, indicated by the persistent presence of the Q wave. Conclusions. Analysis of the electrocardiograms (ECGs) of healthy rats after the introduction of the alginate hydrogel into the heart muscle showed that the correct sinus rhythm is maintained, and the QRS-T complexes retain their shape and duration, indicating that the alginate implant does not cause pathological changes in the ECG. It was demonstrated that the alginate implant, when introduced into the myocardial infarction area, is an indifferent substance that does not exacerbate destructive and inflammatory processes and can be used as a carrier for biologically active substances or drugs for delivery to the damaged area. On the 30th day of observation, in the group with CPHE in the alginate gel, the shape of the QRS complex corresponds to the norm, and signs of heart remodeling are minimal, as evidenced by the absence of animals with a registered Q wave. In contrast, up to 40% of animals in other groups show signs of previous transmural myocardial necrosis with the persistence of the Q wave on the ECG.

Changes in portal pulsatility index induced by a fluid challenge in patients with haemodynamic instability and systemic venous congestion: a prospective cohort study

BackgroundIt is uncertain whether fluid administration can improve patients with systemic venous congestion and haemodynamic instability. This study aimed to describe the changes in systemic venous congestion and peripheral perfusion parameters induced by a fluid challenge in these patients, and to analyse the influence of the fluid responsiveness status on these changes.MethodsThe study is a single-centre prospective cohort study of 36 critically ill ICU patients with haemodynamic instability and a maximum vena cava diameter ≥ 20 mm. Changes in cardiac index during a fluid challenge (4 mL/kg of lactated Ringer’s solution during 5 min) assessed by pulse contour analysis, central venous pressure, ultrasound systemic congestion parameters (portal venous flow pulsatility index, supra hepatic and intrarenal venous Doppler), and peripheral perfusion parameters (capillary refill time and peripheral perfusion index) were assessed in the overall population. All these data were compared between patients presenting a cardiac index increase > 10% during the fluid challenge (fluid responders) and the others (fluid non-responders).ResultsTwenty-eight (78%) patients were admitted for postoperative care following cardiac surgery; their mean ± SD left ventricular ejection fraction was 42 ± 9% and right ventricular dysfunction was found in at least 61% of the patients. The mean ± SD SOFA score was 9 ± 3. Thirteen (36%) patients were fluid responders. The fluid challenge administration induced a significant increase in portal pulsatility index, VExUS score, and central venous pressure without significant difference of these changes between fluid responders and non-responders. No significant change in perfusion parameters was observed.ConclusionFluid administration in patients with haemodynamic instability and systemic venous congestion worsens venous congestion regardless of the fluid responsiveness status, without improving perfusion parameters.

Contour Analysis Tool: An Interactive Tool for Background and Morphology Analysis

We introduce the Contour Analysis Tool (CAT), a Python toolkit aimed at identifying and analyzing structural elements in density maps. CAT employs various contouring techniques, including the lowest-closed contour, linear and logarithmic Otsu thresholding, and average gradient thresholding. These contours can aid in foreground and background segmentation, providing natural limits for both, as well as edge detection and structure identification. Additionally, CAT provides image processing methods such as smoothing, background removal, and image masking. The toolkit features an interactive suite of controls designed for Jupyter environments, enabling users to promptly visualize the effects of different methods and parameters. We describe, test, and demonstrate the performance of CAT, highlighting its potential use cases. CAT is publicly available on GitHub, promoting accessibility and collaboration.

The ghrelin receptor agonist AC01 improves cardiac function in non-human primates and in mice with heart failure by increasing cardiomyocyte contractility

Abstract Background Current therapy for Heart Failure (HF) includes neurohormonal antagonist and modulator drugs that improve remodelling, symptoms and clinical outcomes. However, these drugs do not target the underlying problem of reduced contractility. Improving cardiac contractility without harmful consequences is an unmet need in heart failure therapy. The human peptide hormone ghrelin increases cardiac output in HF patients and increases contractility in murine cardiomyocytes. Purpose We aim to study the cardiovascular effects of a novel oral small molecule ghrelin receptor agonist, AC01, in in vivo and ex vivo mouse models and in non-human primates. Methods HF mice (N=11) underwent pressure-volume loops analysis of cardiac functional and hemodynamic to assess the effects of intravenous AC01 (N=7) or placebo (N=4). Primary cardiomyocytes isolated from HF (N=3) and SHAM (N=5) mice, were treated with combinations of vehicle, AC01, ghrelin receptor antagonist (D-Lys-3-GHRP-6) and pertussis toxin (PTX, a Gαi signalling inhibitor). Live cell imaging was performed to assess cardiomyocyte fractional shortening and Ca2+ signalling, while biochemistry assays were employed to measure PKA activity, and phosphorylation of cardiac Troponin I (cTnI). Cynomolgus monkeys (N=6) were instrumented with devices to measure pulse contour, central aortic blood pressure and ECG devices. Cardiovascular effects of AC01 following single oral dosing were assessed through pulse contour hemodynamic modelling and analysis of autonomic system activation. Results In HF mice, AC01 significantly improved cardiac output (p< 0.01), stroke volume (p< 0.001), and ejection fraction (p< 0.001), and increased nominally the end-systolic pressure-volume curve relationship. In cardiomyocytes, AC01 dose-dependently improved fractional shortening (p< 0.01) without increasing Ca2+ transient amplitudes. AC01 reduced PKA activity (p< 0.05) and reduced phosphorylation of cTnI at Serine 23-24 (p< 0.01). These effects were blocked by pre-treatment with either D-Lys-3-GHRP-6 or PTX. In monkeys, oral AC01 sustainably increased cardiac output (p< 0.05) and stroke volume (p< 0.05) and reduced heart rate without altering central systolic blood pressure or causing tachycardia or arrhythmia. Conclusions AC01 improved CO, SV, and EF in HF mice by increasing contractility in a load-independent fashion. AC01 increased cardiomyocyte contractility without affecting Ca2+ transient amplitudes, through ghrelin receptor Gαi signalling, leading to reduced phosphorylation of cTnI. AC01 improved left ventricle systolic function in monkeys. AC01 is a first in class novel inotrope, which improves contractility in different species without harmful mobilization of Ca2+. AC01 should be explored for the treatment of patients with heart failure.graphical abstract

Impact of ultra-high-resolution on cardiac CT assessment of coronary artery stenoses, plaque burden/composition, and pericoronary adipose tissue attenuation

Abstract Background Conventional coronary computed tomography angiography (CCTA) overestimates stenoses within stents and calcified arteries due to "blooming" artifacts. Ultra-high-resolution coronary CT (UHR-CT) may overcome this limitation because of higher spatial resolution. Purpose To investigate differences in coronary arterial lumen volume, stenosis severity, and plaque composition, between CCTA and UHRCT in patients with stents and/or high coronary calcium scores. Methods As part of a prospective pilot study, 14 patients referred for invasive coronary angiography for evaluation of obstructive CAD underwent UHRCT (Canon Precision, 160 x 0.25mm slices) prior to catheterization. Images of identical cardiac phases were reconstructed in two badges for comparison: 1) Ultra-high resolution using a 1,024 x 1,024 matrix, 0.25 mm, and 2) conventional resolution with a 524 x 524 matrix, 0.5 mm. All images were reconstructed using iterative reconstruction algorithm (AIDR 3D) and a sharp kernel (FC05). For the left main and three coronary arteries, an automated contour analysis using a dedicated software (QAngioCT RE 3.2, Medis, Netherlands) was performed to compare conventional CCTA vs. UHR-CT resolution images across common vascular and plaque metrics, including lumen and vessel volume, plaque burden/volume, plaque composition based upon predefined fixed intensity cut-off values of CT attenuation, minimal and maximal plaque thickness, pericoronary adipose tissue attenuation (PCAT), minimal lumen area and diameter, and diameter stenosis. All lumen and vessel contours were generated by the software, without manual editing. The segment model proposed by the SCCT was used as reference and the lesions classified as greater than 25% stenosis by visual assessment were recorded. The quality of the images was subjectively assessed using a 5-point Likert scale. Vessel segments with scores 1 (severe artifacts) and 2 (pronounced artifacts) were not included in the analysis. Results The mean patient age was 68.5 years (±6.8), 2 were female (14.3%), 6 patients had stents (11 stented segments) and the mean Agatston score was 947.6 (±449) among the 8 non-stented patients. A total of 56 vessels, 133 segments, and 57 lesions were analyzed. Eight segments (6%) were excluded from the analysis due to poor quality. Results on a per segment and per lesion basis were summarized in the table. The mean PCAT value was significantly lower for the UHRCT images compared to NR reconstruction in both segment (p<0.001) and lesion based (p=0.002) analyses. Plaque differentiation varied by UHRCT resulted in a lower fibrous plaque volumes but higher necrotic (low attenuation) plaque volumes. Conclusions Ultra-high-resolution CT image analysis results in significantly different coronary artery plaque volume and PCAT assessment vs. conventional resolution CCTA. These findings have implications for evaluating high-risk plaque features and perivascular inflammation in patients.Table 1

Noninvasive Assessment of Temporal Dynamics in Sympathetic and Parasympathetic Baroreflex Responses.

The baroreflex system is crucial for cardiovascular regulation and autonomic homeostasis. A comprehensive assessment requires understanding the simultaneous temporal dynamics of its multiple functional branches, which traditional methods often overlook. To develop and validate a noninvasive method for simultaneously assessing the temporal dynamics of sympathetic and parasympathetic baroreflexes using pulse contour analysis and the sequence method. Beat-to-beat blood pressure and ECG recordings were analyzed from 55 preoperative cardiothoracic surgery patients in the supine position and 21 subjects from the EUROBAVAR dataset in both supine and standing positions. Systolic arterial pressure (SAP), interbeat interval (IBI), cardiac output (CO), myocardial contraction (dP/dtmax), and systemic vascular resistance (SVR) were estimated using pulse contour analysis. Baroreflex sensitivity (BRS) was calculated via the sequence method and correlated with hemodynamic and heart rate variability (HRV) parameters. Parasympathetic BRS for IBI was correlated with the root mean square of successive differences of ECG RR intervals (RMSSD-HRV) at 0-beat delay. Sympathetic BRS for SVR strongly correlated with SVR, CO, and RMSSD-HRV, particularly at 3-beat delay, and was uniquely associated with SAP at 1-beat delay. Sympathetic BRS for dP/dtmax correlated with dP/dtmax at 1-beat delay. In contrast, BRS for CO correlated with CO and SVR at 0- and 3-beat delays. Postural changes mainly affected parasympathetically-mediated BRS for IBI and, to a lesser extent, the sympathetic vascular and myocardial branches. This method effectively captures multiple baroreflex responses and their temporal dynamics, revealing distinct autonomic mechanisms and the impact of postural changes. Further validation is warranted.

Deciphering the Two-Step Hydride Mechanism of Monoamine Oxidase Flavoenzymes.

The complete two-step hydride transfer mechanism of amine oxidation involved in the metabolism of monoamine neurotransmitters was scrutinized by DFT calculations. In living organisms, this process is catalyzed by monoamine oxidase enzymes. Herein, we focus on some intriguing aspects of the reaction that may have been previously noticed but have not been clarified to date. The first step of the reaction includes the C-H bond cleavage on the methylene group vicinal to the amino group of the monoamine substrate and the subsequent transfer of hydrogen to the N5 atom of the flavin prosthetic group of the enzyme. We confirmed the nature of this step to be hydride transfer by evaluation of the pertinent HOMO-LUMO gap together with analysis of orbital contours alongside the intrinsic reaction coordinate profile. Next, we investigated the rather peculiar intermediate adduct that may form between the amine substrate and the flavin molecule, featuring an unusually long C-N bond of ∼1.62 Å. Although this bond is quite stable in the gas phase, the presence of just a few explicit water molecules facilitates its dissociation almost without energy input so that the amine-flavin intermediate can form an ionic pair instead. We attribute the existence of the unusual C-N bond to a fragile balance between opposing electronic structure effects, as evaluated by the natural bond orbital analysis. In line with this, the intermediate in the solution or in the enzyme active site can exist in two energetically almost equivalent forms, namely, as a covalently bound complex or as an ion pair, as suggested by previous studies. Finally, we characterized the transformation of the intermediate to the fully reduced flavin and imine products via proton transfer from the amino group to the flavin N1 atom, completing the reductive part of the catalytic cycle. Although we found that explicit solvation substantially boosts the kinetics of this step, the corresponding barrier is significantly lower than that in the hydride transfer step, confirming hydrogen abstraction as the rate-limiting step of amine oxidation and validating the two-step hydride transfer mechanism of monoamine oxidases.

The influence of cardiac substructure dose on survival in a large lung cancer stereotactic radiotherapy cohort using a robust personalized contour analysis

Background/Purpose: Radiation-induced cardiac toxicity in lung cancer patients has received increased attention since RTOG 0617. However, large cohort studies with accurate cardiac substructure (CS) contours are lacking, limiting our understanding of the potential influence of individual CSs. Here, we analyse the correlation between CS dose and overall survival (OS) while accounting for deep learning (DL) contouring uncertainty, α/β uncertainty and different modelling approaches. Materials/Methods: This single institution, retrospective cohort study includes 730 patients (early-stage tumours (I or II). All treated: 2009–2019), who received stereotactic body radiotherapy (≥ 5 Gy per fraction). A DL model was trained on 70 manually contoured patients to create 12 cardio-vascular structures. Structures with median dice score above 0.8 and mean surface distance (MSD) <2 mm during testing, were further analysed. Patientspecific CS dose was used to find the correlation between CS dose and OS with elastic net and random survival forest models (with and without confounding clinical factors). The influence of delineation-induced dose uncertainty on OS was investigated by expanding/contracting the DL-created contours using the MSD ± 2 standard deviations. Results: Eight CS contours met the required performance level. The left atrium (LA) mean dose was significant for OS and an LA mean dose of 3.3 Gy (in EQD2) was found as a significant dose stratum. Conclusion: Explicitly accounting for input parameter uncertainty in lung cancer survival modelling was crucial in robustly identifying critical CS dose parameters. Using this robust methodology, LA mean dose was revealed as the most influential CS dose parameter.

Reduced-distortion diffusion weighted imaging for head and neck radiotherapy

Background and purposeQuantitative Diffusion Weighted Imaging (DWI) has potential value in guiding head and neck (HN) cancer radiotherapy. However, clinical translation has been hindered by severe distortions in standard single-shot Echo-Planar-Imaging (ssEPI) and prolonged scan time and low SNR in Turbo-Spin-Echo (ssTSE) sequences. In this study, we evaluate “multi-shot” (ms) msEPI and msTSE acquisitions in the context of HN radiotherapy. Materials and methodsssEPI, ssTSE, msEPI with 2 and 3 shots (2sEPI, 3sEPI), and msTSE DWI were acquired in a phantom, healthy volunteers (N=10), and patients with HN cancer (N=5) on a 3-Tesla wide-bore MRI in radiotherapy simulation RF coil setup, with matched spatial resolution (2x2x5mm) and b = 0, 200, 800 s/mm2.Geometric distortions measured with deformable vector field (DVF) and contour analysis, apparent diffusion coefficient (ADC) values, and signal-to-noise-ratio efficiency (SNReff) were quantified for all scans. ResultsAll techniques significantly (P<1x10-3) reduced distortions compared with ssEPI (DVFmean = 3.1 ± 1.3 mm). Distortions were marginally lower for msTSE (DVFmean = 1.5 ± 0.6 mm) than ssTSE (1.8 ± 0.9 mm), but were slightly higher with 2sEPI and 3sEPI (2.6 ± 1.0 mm, 2.2 ± 1.0 mm). SNReff reduced with decreasing distortion with ssEPI=21.9 ± 7.9, 2sEPI=15.1 ± 5.0, 3sEPI=12.1 ± 4.5, ssTSE=6.0 ± 1.6, and msTSE=5.7 ± 1.9 for b = 0 images. Phantom ADC values were consistent across all protocols (errors ≤ 0.03x10-3mm2/s), but in vivo ADC values were ∼ 4 % lower with msEPI and ∼ 12 % lower with ssTSE/msTSE compared with ssEPI. ConclusionsmsEPI and TSE acquisitions exhibited improved geometric distortion at the cost of SNReff and scan time. While msTSE exhibited the least distortion, 3sEPI may offer an appealing middle-ground with improved geometric fidelity but superior efficiency and in vivo ADC quantification.

Advanced CNN models in gastric cancer diagnosis: enhancing endoscopic image analysis with deep transfer learning.

The rapid advancement of science and technology has significantly expanded the capabilities of artificial intelligence, enhancing diagnostic accuracy for gastric cancer. This research aims to utilize endoscopic images to identify various gastric disorders using an advanced Convolutional Neural Network (CNN) model. The Kvasir dataset, comprising images of normal Z-line, normal pylorus, ulcerative colitis, stool, and polyps, was used. Images were pre-processed and graphically analyzed to understand pixel intensity patterns, followed by feature extraction using adaptive thresholding and contour analysis for morphological values. Five deep transfer learning models-NASNetMobile, EfficientNetB5, EfficientNetB6, InceptionV3, DenseNet169-and a hybrid model combining EfficientNetB6 and DenseNet169 were evaluated using various performance metrics. For the complete images of gastric cancer, EfficientNetB6 computed the top performance with 99.88% accuracy on a loss of 0.049. Additionally, InceptionV3 achieved the highest testing accuracy of 97.94% for detecting normal pylorus, while EfficientNetB6 excelled in detecting ulcerative colitis and normal Z-line with accuracies of 98.8% and 97.85%, respectively. EfficientNetB5 performed best for polyps and stool with accuracies of 98.40% and 96.86%, respectively.The study demonstrates that deep transfer learning techniques can effectively predict and classify different types of gastric cancer at early stages, aiding experts in diagnosis and detection.

Multidimensional Characterization and Separation of Ultrafine Particles: Insights and Advances by Means of Froth Flotation

Particle systems and their efficient and precise separation are becoming increasingly complex. Therefore, instead of focusing on a single separation feature, a multidimensional approach is needed where more than one particle property is considered. This, however, requires the precise characterization of the particle system, which is especially challenging for fine particles with sizes below 10 µm. This paper discusses the benefits and limitations of different characterization techniques, including optical contour analysis, inverse gas chromatography, flow cytometry, and SEM-based image analysis. The separation of ultrafine particles was investigated for a binary system using froth flotation, where a novel developed flotation apparatus is used. A special focus was placed on the multidimensional evaluation of the separation according to the particle properties of size, shape, and wettability, which was addressed via multivariate Tromp and entropy functions. The results emphasize the intricacy of the flotation process and the complex interaction of the individual particle properties and process parameters. The investigations contribute to the understanding of the characterization of particulate properties as well as the separation behavior of ultrafine particles via froth flotation, especially in the case of a multidimensional approach.

One‐Step Local Acceleration Process of Ultra‐Relativistic Electrons in the Center of the Outer Radiation Belt: Observations

AbstractUltra‐relativistic (&gt;3 MeV) electrons are considered as a novel, separate population in the Earth's radiation belts since their loss and acceleration features are distinct from relativistic (∼MeV) electrons. The dominant acceleration mechanism of ultra‐relativistic electrons remains a subject of ongoing debate. Some studies suggest that the acceleration mechanism of ultra‐relativistic electrons is energy‐dependent: local acceleration dominants the enhancement of ∼3–5 MeV electrons while two‐step acceleration process leading by radial diffusion effects for ∼7 MeV electrons. However, a recent study (https://doi.org/10.1126/sciadv.abc0380) theoretically demonstrated that local acceleration could accelerate electrons up to &gt;7 MeV directly under the extreme plasma depletion. In this study, we report four enhancement events of ultra‐relativistic electrons that occurred in September and October 2017. Analysis of phase space density (PSD) radial profiles and contours demonstrate that local acceleration plays the dominant role in the enhancements of ∼7 MeV electrons in mid‐September and mid‐October, supported by persistently growing peaks in electron PSD. While enhancements of ultra‐relativistic electrons in other two events still show energy‐dependent phenomenon, our results provide the observation evidence that one‐step local acceleration process can lead to the enhancement of ∼7 MeV electrons in some events. We suggest that the acceleration process of ultra‐relativistic electrons may be subject to the efficiency of local acceleration.

Digital bio-dosimeter for detection of deformed biological cells irradiated by ionizing radiations

In this paper, a digital bio-dosimeter (DBD) with a square window size of 7 × 7 pixels is proposed for the quantitative detection of the deformed biological cells irradiated by X-rays with different energies and γ-rays from 60Co. The basic idea of the DBD is to compute the energy of the bio-dosimeter window size by summing up the entire gray levels. Peripheral blood films (PBFs) from male albino rats irradiated by ionizing radiations are prepared and photographed using an Automatic Image Contour Analysis system with high magnification to produce a 2D image. The surf function in MATLAB is used to convert the 2D image to a 3D shaded surface to resample the date more finely. The proposed DBD shows that the computed energies on the boundaries of the normal RBCs are nearly the same, while the computed energies on the boundaries of the deformed cells are significantly larger.

Contour Analysis for Heat Transfer Rate in a Wedge Geometry with Non-Uniform Shapes Nanofluid: Gradient Descent Machine Learning Technique

The flow of boundary layer over porous wedge nanofluids, hybrid nanofluids, and ternary hybrid nanofluids under constant transverse magnetic field and heat radiation have all been examined. The following cases are taken into consideration: Zirconium oxide + A A7072 + Polyethylene Glycol-water (Case-2); Magnesium oxide + Polyethylene Glycol-water + AA7072 + Zirconium oxide (Case-3); Polyethylene-water as base fluid; nanofluid, hybrid nanofluid, ternary hybrid nanofluid cases. The governing equations are solved using the shooting technique with the fourth-order Runge-Kutta method. The approximate relationship between temperature, velocity, heat transfer rate, and friction factor coefficient at the wedge is shown graphically for a range of values of the pertinent parameters. The flow of boundary layer over porous wedge nanofluids, hybrid nanofluids, and ternary hybrid nanofluids under constant transverse magnetic field and heat radiation have all been examined. Cases containing Polyethylene Glycol-Water + AA7072 (Case-1), Zirconium oxide + A A7072 + Polyethylene Glycol-water (Case-2), and Magnesium oxide + Polyethylene Glycol-water + AA7072 + Zirconium oxide (Case-3) are taken into consideration. Polyethylene water is used as the base fluid. The governing equations are solved using the shooting approach and Runge-Kutta fourth order. The approximate relationship between temperature, velocity, heat transfer rate, and friction factor coefficient at the wedge is shown graphically for a range of values of the pertinent parameters. Comparing Ternary hybrid nanofluid to nanofluid and hybrid nanofluid situations, it is discovered that the skin friction coefficient is higher. It has also been noted that ternary hybrid nanofluids have a higher Nusselt number than hybrid and nanofluids. When applied to specific dimensionless parameters, the basic linear regression machine learning technique using the gradient descent method accurately predicts the truth values. Finding the optimisation conditions values based on the key factors influencing the Response Function is easier with the RSM method's help. When applied to specific dimensionless parameters, simple linear regression machine learning using the gradient descent method accurately predicts the truth values.