Processing Software Research Articles

Physiological quality of Passiflora edulis Sims seeds evaluated by different processing methods, storage times and packages

ABSTRACT Maintaining seed vigour during the storage process is essential for the success of germplasm banks of sexually propagated species such as Passiflora edulis. However, the literature is still scarce regarding efficient preservation methods, especially for long periods. The objective of this study was to evaluate the effect of different seed processing methods, types of packaging and storage conditions of Passiflora edulis seeds for a period of five years. Different seed processing methods (natural fermentation and use of a mixer), packaging (Falcon tubes, plastic bags and paper bags), storage temperatures (room temperature, cold chamber and refrigerator) and evaluation times (one, three and five years) were analysed. Seeds stored in a refrigerator and cold chamber maintained high germination (>90%) for up to five years. However, seeds stored at room temperature reduced their viability after one year of storage. No significant variations were observed between the seed processing and packaging methods evaluated. Absence of respiratory activity was confirmed by the tetrazolium test performed on seeds stored for five years at room temperature. To maintain the vigour of P. edulis seeds, it is recommended to store them in a cold room or refrigerator in different packaging and using different methods for seed extraction.

Application of thermodynamic equilibrium modelling to predict slagging and fouling tendencies of bituminous coal and wheat straw blends

The combustion or co-combustion of biomass or alternative fuels is important in the energy sector because of the need to reduce the share of fossil fuels. This article is a continuation of previous studies on the behaviour of the mineral matter of selected fuels during the sintering processes. The blends of wheat straw biomass from Polish crops (WS) with bituminous coal from the Makoszowa mine (BC) were studied. The study included proximate and ultimate analysis and oxide analysis of ash blends with the following composition: 10wt% WS/90wt%BC, 25wt% WS/75wt%BC and 50wt% WS/50wt%BC. Based on the oxide content, a prediction (using FactSage 8.0 software) of the sintering process of the mixtures tested. The following parameters were determined: slag phase content, specific heat at constant pressure, and ash density. The fracture stresses tests were carried out using the mechanical test. Pressure tests were also performed using the pressure drop test method. The test results of all test methods used were compared with each other. On the basis of this comparison, a clear correlation was found between the sintering temperatures determined by the mechanical method and the pressure drop method and the physical properties of the ashes, such as density and heat capacity, as well as the chemical properties, i.e. the content of the slag phase. The results of the presented research are a valuable addition to the previous work of the authors. The goal of this work is to develop a precise and measurably simple method to determine the sintering temperature of ashes. This is an extremely important issue, especially in the case of the need to use a wide range of fuels in the energy industry.

Low power tactile sensory neuron using nanoparticle-based strain sensor and memristor

Endowing strain sensors with neuromorphic computing capabilities could permit the efficient processing of tactile information on the edge. The realization of such functionalities from a simple circuit without software processing holds promise for attaining skin-based perception. Here, leveraging the intrinsic neuronal plasticity of memristive neurons, various firing patterns induced by the applied strain were demonstrated. More specifically, tonic, bursting, transition from tonic to bursting, adaptive, and nociceptive activities were captured. The implementation of these patterns permits the facile translation of the analog pressure signals into digital spikes, attaining accurate perception of various tactile characteristics. The tactile sensory neuron consisting of an RC circuit was composed of a SiO2-based conductive bridge memristor exhibiting leaky integrate-and-fire properties and a Pt nanoparticles (NPs)-based strain sensor with a gauge factor of ∼270. A dense layer of Pt NPs was also used as the bottom electrode for the memristive element, yielding the manifestation of a threshold switching mode with a switching voltage of only ∼350 mV and an exceptional switching ratio of 107. Our work provides valuable insights for developing low power neurons with tactile feedback for prosthetics and robotics applications.

A fine-tuning enhanced RAG system with quantized influence measure as AI judge

This study presents an innovative enhancement to retrieval-augmented generation (RAG) systems by seamlessly integrating fine-tuned large language models (LLMs) with vector databases. This integration capitalizes on the combined strengths of structured data retrieval and the nuanced comprehension provided by advanced LLMs. Central to our approach are the LoRA and QLoRA methodologies, which stand at the forefront of model refinement through parameter-efficient fine-tuning and memory optimization. A novel feature of our research is the incorporation of user feedback directly into the training process, ensuring the model’s continuous adaptation to user expectations and thus, improving its performance and applicability. Additionally, we introduce a Quantized Influence Measure (QIM) as an innovative “AI Judge” mechanism to enhance the precision of result selection, further refining the system’s accuracy. Accompanied by an executive diagram and a detailed algorithm for fine-tuning QLoRA, our work provides a comprehensive framework for implementing these advancements within chatbot technologies. This research contributes significant insights into LLM optimization for specific uses and heralds new directions for further development in retrieval-augmented models. Through extensive experimentation and analysis, our findings lay a robust foundation for future advancements in chatbot technology and retrieval systems, marking a significant step forward in the creation of more sophisticated, precise, and user-centric conversational AI systems. We make the dataset, the data processing package huggify-data, the model, and the app publicly available for the community.

Analysis methods for large-scale neuronal recordings.

Simultaneous recordings from hundreds or thousands of neurons are becoming routine because of innovations in instrumentation, molecular tools, and data processing software. Such recordings can be analyzed with data science methods, but it is not immediately clear what methods to use or how to adapt them for neuroscience applications. We review, categorize, and illustrate diverse analysis methods for neural population recordings and describe how these methods have been used to make progress on longstanding questions in neuroscience. We review a variety of approaches, ranging from the mathematically simple to the complex, from exploratory to hypothesis-driven, and from recently developed to more established methods. We also illustrate some of the common statistical pitfalls in analyzing large-scale neural data.

Interactive software for processing, compilation, and interpretation of seafloor heat‐flow data, including analysis of measurement uncertainties

Interactive software for processing, compilation, and interpretation of seafloor heat‐flow data, including analysis of measurement uncertainties

Three-dimensional evaluation of maxillofacial symmetry improvement following orthognathic surgery in patients with asymmetrical jaw deformities.

The aim of this study was to clarify the three-dimensional changes in maxillofacial morphology following orthognathic surgery using 3D-CT in patients with asymmetrical jaw deformities. The subjects were 30 patients with asymmetrical jaw deformities. Three-dimensional images taken preoperatively and 6months postoperatively were re-aligned using image processing software with the horizontal plane, coronal plane, and midsagittal plane as reference axes. Thirty-nine measurements including 28 distances, nine angles, and two volumes were recorded, and differences between preoperative and postoperative measurements and percentage differences between paired measurements on the deviated and unevolved sides were calculated. Translational and rotational movements of the maxillary dentition and mandibular body and the mandibular ramus internally rotating contributed to improved symmetry of the maxillofacial morphology, but the degree and proportion of these changes varied from case to case and mild asymmetry remained even after surgery. 3D-CT analysis of maxillofacial morphology is essential to accurately evaluate the asymmetry of hard and soft tissue morphology in the maxillofacial region and the degree of improvement after orthognathic surgery, and the tooth movement during preoperative orthodontic treatment should be determined taking into account the movement of the upper and lower jaws during orthognathic surgery.

7-axis synchronization-integrated on-the-fly laser texturing system of freeform surface: design and development

Abstract While laser surface texturing (LST) is a promising manufacturing technique for surface functionalization, simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging, due to continuously varied geometries of laser-matter incidence. In the present work, we propose a novel manufacturing system of 7-axis on-the-fly LST for complex curved surface, based on the integrated synchronization of 5-axis linkage motion platform with 2-axis galvanometer. Specifically, the algorithm for decomposing spatial texture trajectory on curved surface into low-frequency and high-frequency parts is established, based on which the kinematic model of synchronized 7-axis system is developed to derive the motion of each axis in both 5-axis linkage motion platform and 2-axis galvanometer simultaneously. Subsequently, the synchronized 7-axis LST system is experimentally realized, including the setup of mechanical stages integrated with optical path, the configuration of numerical control unit, and the development of processing software. Finally, case study of 7-axis on-the-fly LST of freeform aluminum surface is performed, and the advantages in terms of processing efficiency and texturing accuracy over 5-axis linkage LST are demonstrated. The correlation of reduced following errors between mechanical stages with the promoted performance of curved surface texturing by the 7-axis on-the-fly LST is further analyzed. Current work provides a feasible solution for establishing the manufacturing system for high performance LST of complex curved surface.

Empirical Evaluation and Simulation of the Impact of Global Navigation Satellite System Solutions on Uncrewed Aircraft System–Structure from Motion for Shoreline Mapping and Charting

Uncrewed aircraft systems (UASs) and structure-from-motion/multi-view stereo (SfM/MVS) photogrammetry are efficient methods for mapping terrain at local geographic scales. Traditionally, indirect georeferencing using ground control points (GCPs) is used to georeference the UAS image locations before further processing in SfM software. However, this is a tedious practice and unsuitable for surveying remote or inaccessible areas. Direct georeferencing is a plausible alternative that requires no GCPs. It relies on global navigation satellite system (GNSS) technology to georeference the UAS image locations. This research combined field experiments and simulation to investigate GNSS-based post-processed kinematic (PPK) as a means to eliminate or reduce reliance on GCPs for shoreline mapping and charting. The study also conducted a brief comparison of real-time network (RTN) and precise point positioning (PPP) performances for the same purpose. Ancillary experiments evaluated the effects of PPK base station distance and GNSS sample rate on the accuracy of derived 3D point clouds and digital elevation models (DEMs). Vertical root mean square errors (RMSEz), scaled to the 95% confidence interval using an assumption of normally-distributed errors, were desired to be within 0.5 m to satisfy National Oceanic and Atmospheric Administration (NOAA) requirements for nautical charting. Simulations used a Monte Carlo approach and empirical tests to examine the influence of GNSS performance on the quality of derived 3D point clouds. RTN and PPK results consistently yielded RMSEz values within 10 cm, thus satisfying NOAA requirements for nautical charting. PPP did not meet the accuracy requirements but showed promising results that prompt further investigation. PPK experiments using higher GNSS sample rates did not always provide the best accuracies. GNSS performance and model accuracies were enhanced when using base stations located within 30 km of the survey site. Results without using GCPs observed a direct relationship between point cloud accuracy and GNSS performance, with R2 values reaching up to 0.97.

Internal adaptation assessment of implant infrastructures manufactured through five different techniques (heat-press, milling, lost wax, calcinable cylinder, and CAD/Waxx®): an in vitro pilot study

IntroductionThe aim of this study was to evaluate the fit performance of implant infrastructures manufactured by five different techniques: heat-press (IPS), milling (ZIR), lost wax (CER), calcinable cylinder (CAL), and CAD/Waxx® (CAD).MethodsThe methodology was based on the Replica Technique, which can simulate and evaluate the fit of the infrastructure on the implant component. Thus, each infrastructure was internally filled with low-viscosity silicone addition and seated on the component until its final setting, obtaining the replica of the cementation space. After removing the coping containing the silicone film, light-density silicone was inserted addition in place of the components, and in its surroundings, condensation silicone was applied, establishing support for the assembly. The joint was sectioned mesiodistally, photographed, and analyzed in image processing software in order to measure the thickness of the interface infrastructure/implant at five different areas: marginal opening (M), gingival-axial angle (G-A), axial region (A), axial-occlusal angle (A-O) and occlusal surface (O).ResultsThe lowest and the highest average thickness between groups was, respectively, IPS: 187.5 μm and CAD: 221.6 μm, with statistically significant differences (p < 0.01) among all five groups; the lowest and the highest average of all groups in each point was, respectively, A: 99.86 μm and O: 279.78 μm. The IPS group exhibited the lowest value of the internal space of the infrastructure on the implant. The marginal region of all groups demonstrated a correlation with the findings in the literature, except the CAL group; otherwise, the occlusal region and the angles A-O and G-A exhibited values beyond that expected.DiscussionIt was possible to conclude that the five infrastructure groups presented different adaptations, suggesting possible interference in the internal spaces due to the manufacturing infrastructure processes.

A Parametric Study on the Stability, Geometry and Hardness of AISI 308LSi WAAM-GMAW

Wire arc additive manufacturing (WAAM) has been established to be an efficient and cost-effective additive manufacturing technique for fabricating functional metallic parts from scratch. However, there is need to determine optimal processing condition for each material system to produce high-quality parts. In this work, a parametric study of WAAM of AISI 308LSi was performed to determine the processing condition(s) at which single tracks of high dimensional accuracy, excellent geometry, no visible crack and pore, and high hardness required for high-quality multi-track deposition can be achieved. The track geometries were investigated using a combination of optical microscopy and image processing software. The microstructure and hardness of the deposited single tracks were examined using optical microscopy and Vickers hardness tester respectively. A process map predicting the process stability of WAAM of AISI 308LSi was developed within a process window. Continuous single tracks of high dimensional accuracy were produced from a stable deposition process. The process becomes unstable whenever the wire deposition volume per unit length of track is in excess of the available heat energy per unit length of track. The wire feed rate and traverse speed significantly influence the stability and geometry of the single tracks. The processing conditions at which single tracks of low wetting angle (<90◦), high aspect ratio (>1.5), high surface quality, and high hardness (close to the as-received material) can be deposited were determined. These processing conditions were considered suitable for the fabrication, surface modification and repair of functional engineering parts made of 308LSi stainless steel.

A method for data conversion of exposure level testers using sinusoidal alternating magnetic fields

Flux density measurements provide valuable information on the state of electrical appliances, which can be utilised for improving the safety and the performance of the associated system. Exposure level testers with a B-field probe are widely used for flux density measurements but they can only perform a time-domain measurement and display it as output voltage related to flux density. In other words, they cannot output flux density directly, which brings many inconveniences. These drawbacks can be improved using data conversion coefficients. However, the test frequencies of most exposure level testers are greater than 1 Hz. They are unable to calculate the data conversion coefficients using a constant magnetic field. This paper proposes a method for data conversion of exposure level testers using alternating magnetic fields to measure flux density directly: the flux density conversion model was established; the mathematical relationship between the mean value of the voltage signal output by the exposure level testers and its stable display value was deduced; and an experimental test of the conversion coefficients was carried out. The results show that the error between the value measured using the new technique and the display value of the exposure level tester at different frequencies is small. This method can trace the flux density in both the time and frequency domains through software processing algorithms without changing the exposure level tester itself. By applying sinusoidal magnetic fields and using the conversion factor, then existing testers can be used to measure flux density directly.

Dynamic visualization study of in situ cleaning of polystyrene microparticles off silicon wafer surface

With the improvement of chip performance, the requirements for cleaning the surface of silicon wafers are becoming higher. However, due to equipment and technology, it is difficult to observe the complex motion processes of particles at the microscopic scale. In this paper, an in situ dynamic visualization experiment on the cleaning of Polystyrene Latex (PSL) on the surface of silicon wafers is carried out by using a high-speed camera and image processing software. The mechanical behavior of PSL particles in fluid was investigated on a microscopic scale, and the trajectory and force of the polystyrene particles on the surface of the wafers were visualized, which provided a new perspective for understanding the complex cleaning process. Theoretical models were developed to explain the motion characteristics of the particles by calculating parameters such as van der Waals force, surface tension, and trailing force, and these models provide a theoretical basis for optimizing the cleaning process. There are four particle motion modes in the fluid: (1) interface capture, where the particles on the surface of silicon wafer are trapped by gas–liquid interface under surface tension; (2) particle collision, where the particles captured by the water film collide with the particles on the wafer surface to make the latter leave the silicon wafer; (3) jump attachment, where the particles jump and attach to the surface of the particle group under the action of lift; and (4) wall surface movement, where the particles start up under the action of water flow and then leave the silicon wafer quickly.

FindGSEP: estimating genome size of polyploid species using k-mer frequencies.

Estimating genome size using k-mer frequencies, which plays a fundamental role in designing genome sequencing and analysis projects, has remained challenging for polyploid species, i.e., ploidy p > 2. To address this, we introduce "findGSEP," which is designed based on iterative curve fitting of k-mer frequencies. Precisely, it first disentangles up to p normal distributions by analyzing k-mer frequencies in whole genome sequencing of the focal species. Second, it computes the sizes of genomic regions related to 1∼p (homologous) chromosome(s) using each respective curve fitting, from which it infers the full polyploid and average haploid genome size. "findGSEP" can handle any level of ploidy p, and infer more accurate genome size than other well-known tools, as shown by tests using simulated and real genomic sequencing data of various species including octoploids. "findGSEP" was implemented as a web server, which is freely available at http://146.56.237.198:3838/findGSEP/. Also, "findGSEP" was implemented as an R package for parallel processing of multiple samples. Source code and tutorial on its installation and usage is available at https://github.com/sperfu/findGSEP.

Structures of Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus virions reveal species-specific tegument and envelope features.

Discovered in 1964, Epstein-Barr virus (EBV) is the first identified human oncogenic virus and the founding member of the gammaherpesvirus subfamily. In 1994, another cancer-causing virus was discovered in lesions of AIDS patients and later named Kaposi's sarcoma-associated herpesvirus (KSHV), the second human gammaherpesvirus. Despite the historical importance of EBV and KSHV, technical difficulties with isolating large quantities of these viruses and the pleiomorphic nature of their envelope and tegument layers have limited structural characterization of their virions. In this study, we employed the latest technologies in cryogenic electron microscopy (cryoEM) and tomography (cryoET) supplemented with an artificial intelligence-powered data processing software package to reconstruct 3D structures of the EBV and KSHV virions. We uncovered unique properties of the envelope glycoproteins and tegument layers of both EBV and KSHV. Comparison of these features with their non-tumorigenic counterparts provides insights into their relevance during infection.

Evaluating the feasibility of upper arm ECG for cardiac monitoring

Abstract Background Ambulatory electrocardiogram (ECG) monitoring is essential for detecting paroxysmal cardiac events and tracking long-term physiological parameters. However, traditional Holter devices are cumbersome, restrict movement, and can cause skin irritation, resulting in sub-optimal patient compliance during extended monitoring periods. Wearable devices utilizing non-conventional form factors are emerging as promising non-intrusive alternatives for ECG monitoring. Purpose To determine the optimal location for single-lead ECG acquisition on the upper arm and assess the feasibility of using dry electrode armbands for cardiac monitoring when coupled with robust ECG processing software. Methods Stationary ECGs from 20 healthy adult participants were recorded across a two-phase data collection protocol and processed with clinically validated ECG software. In the first phase, the average signal amplitudes of wet-electrode ECGs obtained from 30 different configurations across the mid-brachial and proximal-brachial regions of the upper arm were assessed. In the second, the performance of two proprietary dry-electrode armbands, featuring either a single-point or three-point electrode strap, were evaluated on the optimal upper arm configuration using QRS detection and heart rate (HR) metrics. Comparative analysis was performed throughout using data simultaneously acquired on a gold standard Holter device in modified lead III (MLIII) configuration. Performance metrics were calculated relative to manually generated signal annotations. Results Wet-electrode-acquired ECGs from the proximal-brachial region exhibited significantly higher average signal amplitudes (0.12 ± 0.06 mV) compared to those from the mid-brachial region (0.05 ± 0.04 mV) of the upper arm (p < 0.05). The optimal configuration (A-F), positioned at the lateral and medial extents of the proximal-brachial region, demonstrated comparable average signal amplitudes (0.16 ± 0.07 mV, 0.16 ± 0.06 mV, 0.19 ± 0.08 mV) for single-point dry, three-point dry, and wet-electrode setups, respectively. Upon processing with ECG software, data from optimal dry-electrode configurations showed excellent average QRS sensitivity and specificity of 98.2% and 98.9% for the one-point strap, and 98.9% and 99.8% for the three-point strap, respectively. HR metrics from the optimized dry-electrode setups were comparable in accuracy to those derived from the reference Holter device, with the average HR error being similar across the three-point dry electrode strap (0.57% ± 0.28%), one-point dry electrode strap (1.16% ± 1.46%), and Holter device (0.74% ± 1.50%). Conclusion(s) Optimized upper arm single-lead ECG with dry electrodes can yield signals with sufficient amplitude and quality for automated ECG analysis. Coupled with robust ECG signal processing software, the cardiac metrics obtained from the optimized upper arm setups exhibited comparable performance to those derived from medical Holter data.

Serial changes in left and right ventricular global longitudinal strain in symptomatic obstructive hypertrophic cardiomyopathy treated with mavacamten: insights from VALOR-HCM trial

Abstract Background In severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM), the VALOR-HCM phase 3 randomized, double-blind, placebo-controlled clinical trial demonstrated that mavacamten, reduces the need for septal reduction therapy with sustained improvement in left ventricular outflow tract gradients and symptoms. As a cardiac myosin inhibitor, mavacamten’s mechanism of action reduces myocardial hypercontractility. Global longitudinal strain (GLS), a measure of regional myocardial function, is a more sensitive marker of systolic function and can complement left ventricular ejection fraction (LVEF). Objective We sought to assess serial changes in LV and right ventricular (RV)-GLS in patients enrolled in the VALOR-HCM study. Methods VALOR-HCM included 112 symptomatic obstructive HCM patients (mean 60 years, 51% male, LVEF 68%). Patients assigned to mavacamten at baseline continued the drug for 56 weeks (n=56) and those assigned to placebo crossed over to mavacamten (n=52) from week 16-56 (40-week exposure). LV and RV-GLS assessment was performed according to the current American and European guideline recommendations using a vendor-neutral post processing software. Non-foreshortened apical (4, 3 and 2-chamber) views were used to obtain peak value of LV-GLS. For RV-GLS, RV focused 4-chamber view was used to calculate RV 4-chamber and free wall strain. A more negative strain value is favorable. Results Serial changes in LVEF, average LV-GLS, and RV-GLS (4-chamber and free wall) from baseline to week 56 are shown in the Figure. Despite preserved LVEF at baseline, average baseline LV-GLS was abnormal. There were significant and continued improvements in LV-GLS in the total group from baseline to week 56. 12 patients had transient reduction in LVEF (<50%) requiring temporary drug interruption (permanent discontinuation in 3). The LV-GLS in this subgroup was worse at baseline compared to the total study population, with no significant worsening from baseline through week 56. In the overall population, excluding these 12 patients, LV-GLS demonstrated an improvement sustained through week 56. Both free wall and 4-chamber RV-GLS were abnormal at baseline and remained unchanged from baseline to week 56. Conclusions In the VALOR-HCM trial, despite hypercontractile LVEF at baseline, average baseline LV-GLS was worse than normal reference values. Treatment with mavacamten resulted in an improvement in LV-GLS from baseline through Week 56 (with no significant worsening of LV-GLS in the subgroup who experienced any reduction in LVEF <50%), suggesting a favorable long-term impact on regional LV systolic function due to the reduction of cardiac hypercontractility. Additionally, there was no significant detrimental impact on RV systolic function on serial GLS assessment.Serial changes in LV and RV GLS in VALOR

Serial changes in left atrial strain in symptomatic obstructive hypertrophic cardiomyopathy treated with mavacamten: insights from VALOR-HCM trial

Abstract Background In severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM), the VALOR-HCM phase 3 randomized, double-blind, placebo-controlled clinical trial demonstrated that mavacamten, a cardiac myosin inhibitor, reduces the eligibility for septal reduction therapy with sustained improvement in left ventricular (LV) outflow tract gradients and symptoms. Mavacamten also resulted in favorable cardiac remodeling, including improvement in left atrial volume index (LAVI), LV diastolic function, and biomarkers (NT-proBNP and troponin T). However, the impact of mavacamten on LA function is not known. Objective We sought to assess serial changes in LA strain measures in patients enrolled in the VALOR-HCM trial. Methods VALOR-HCM included 112 symptomatic obstructive HCM patients (mean age 60 years, 51% male). Patients assigned to mavacamten at baseline (n=56) continued therapy for 56 weeks and those assigned to placebo crossed over to mavacamten (n=52) from week 16-56 (40-week exposure). Echocardiographic LA strain assessment was performed according to the current American and European guideline recommendations, using a vendor-neutral post processing software. For assessment of LA strain components (reservoir, conduit, and contraction), the non-foreshortened apical 4-chamber view was utilized. The zero reference was set at end-diastole. Results Serial changes in LAVI and all components of mean LA strain from baseline to week 56 are shown in the Figure. At baseline, LAVI and all mean LA strain values were worse than reported normal mean thresholds. There was a continued and significant improvement in all 3 LA strain values, from baseline to week 56, along with a significant reduction in LAVI. Improvement in LAVI was seen earlier than improvements in LA strain. There was a significant inverse correlation between change in mean LAVI and LA reservoir strain from baseline to week 56 (r= -0.42, p<0.001). Conclusions In the VALOR-HCM trial, average LAVI and baseline LA strain values were significantly worse than reported normal thresholds. Treatment with mavacamten resulted in an improvement in LAVI and LA strain values from baseline through week 56 suggesting a sustained favorable impact on cardiac remodeling. The advantageous cardiac remodeling associated with long-term treatment with mavacamten may in turn have a favorable impact on the observed high burden of atrial tachyarrhythmias in HCM.Serial changes in LA strain in VALOR-HCM

Diabetes worsens the adverse association between myocardial diffuse fibrosis and left ventricular strain

Abstract Background Heart failure is a common cardiovascular complication to diabetes. Increased fibrosis of the myocardium has been suggested to be a mechanism, however, no convincing clinical evidence has so far been presented. A better understanding of how myocardial tissue characteristics influence functional aberration in diabetes could aid diagnosis, risk assessment and guide treatment. Native T1 is a CMR marker of diffuse fibrosis with diagnostic and prognostic value (1,2), and feature tracking (CMR-FT) strain is a sensitive measure of myocardial systolic function. In this study, we evaluated the association of CMR markers of fibrosis with markers of systolic function in individuals with and without diabetes. Purpose To understand the relationship between native T1 and myocardial strain and how diabetes may affect this. Methods Participants from the UK Biobank population imaging study were included. Left ventricular global longitudinal strain (GLS) was derived using a semi-automated batch processing software tool. Native T1 was derived from segmentation of the entire short axis slice using an automated quality control tool, excluding scans with predicted dice score of <0.7. Multivariable linear models were used with the strain metrics as the outcome variable and native T1 and diabetes as the exposure variables. These models were adjusted for age, sex, BMI, ethnicity, smoking and alcohol status, prevalent hypertension hypercholesterolaemia and coronary artery disease. The effect of interaction between diabetes and native T1 on GLS was examined by introducing an interaction term. Results In total 41,533 participants were included, of which 1957 had diabetes – see Table 1 for baseline characteristics. The average GLS measured for those with diabetes was -17% and was -18% for those without. The average native T1 in those with diabetes was 935ms and 933ms for those without on the background of greater prevalence of cardiovascular risk factors in those with diabetes. In model adjusted for all relevant co-variates, individuals with diabetes had worse GLS measured compared to those without diabetes (β-coefficient: 0.51, p value <0.001). Increasing fibrosis (native T1) was associated with worsening GLS (β-coefficient: 0.005, p value <0.001) in all participants. However, in those with diabetes, increasing native T1 was associated with a greater decline in GLS compared to those without diabetes (interaction term β-coefficient: 0.005, p value <0.001), with a relative impairment seen within normal ranges for native T1 - see Figure 1. Conclusion(s) This is the largest study of its kind to demonstrate a dose dependent relationship between increasing native T1, representing potential myocardial fibrosis, and myocardial strain, representing cardiac dysfunction. Our findings indicate that increased fibrosis alone does not explain the higher risk of HF in diabetes, other mechanisms, perhaps intracellular, might be at play.

A new free radical scavenger, resorcimoline, prevents ischaemia/reperfusion injury in the heart

Abstract Introduction Ischaemic heart disease remains the leading cause of death worldwide. Early coronary revascularisation is the most important treatment. Recent findings have revealed that reactive oxygen species (ROS) can lead to tissue damage following coronary artery revascularisation, known as ischaemia-reperfusion injury. In this study, we focused on resorcimoline, a new free radical scavenger that was generated during the synthesis of dimethylresveratrol and dimethylpiceatannol. Last year, we reported the scavenging activity in vitro against multiple ROS, confirmed by the electron spin resonance spectrometry (Ref. 1). Purpose This study aimed to assess the potential of resorcimoline as a novel therapeutic treatment for reducing the degree of infarction caused by myocardial ischaemia, by eliminating ROS generated during myocardial ischaemia-reperfusion. Methods Nine-to-eleven-week-old male Wistar rats were subjected to acute myocardial ischaemia induced by ligation of the left anterior descending coronary artery for 30 minutes, followed by reperfusion for 24 hours. Rats received intravenous injections of resorcimoline at 6 mg/kg before coronary ligation or saline as a control (n = 9 vs. n = 8). The heart sections were double-stained with Evans blue 1% and triphenyltetrazolium chloride 1% to assess infarct area and area-at-risk. For immunohistochemical study, the other ischaemia/reperfusion models were treated with resorcimoline and saline (n = 7 vs. n = 7) as above, and the middle parts of the hearts were embedded in optimal cutting temperature compound and quickly frozen. In the H＆E-stained section, the infarct border zone was defined as a 2-mm band surrounding the necrosis area. Troponin I levels in serum were measured using ELISA. Primary cultured cardiomyocytes were treated with 10 μM angiotensin II for 3.5 hours and then exposed to resorcimoline for 30 minutes at an increasing dosage. A cellular ROS assay kit was used to assess the levels of ROS in the cardiomyocytes and the number of cells was counted with DAPI stain using an image processing software. Results Infarct size in resorcimoline-treated animals was significantly smaller than in control animals (41.8±19.4% vs. 60.8±12.9%, p=0.03, Fig. 1A) and area-at-risk was not significantly different (58.0±27.8% vs. 51.9±18.5%, p=0.61). Apoptotic cells in the border zone were significantly reduced in resorcimoline-treated animals (32.0±11.7% vs. 55.1±16.9%, p=0.01, Fig. 1B). Troponin I levels in resorcimoline-treated animals were significantly lower than in control animals (4524±3596 vs. 7856±4653, p=0.04, Fig. 1C). resorcimoline significantly reduced angiotensin II-induced ROS in cardiomyocytes in a concentration-dependent manner (Fig. 2A,B). Conclusion This novel compound, resorcimoline, can reduce infarct size induced by coronary ischaemia-reperfusion injury by reducing the ROS damage to myocardiocytes in the border zone and cellular ROS levels in cardiomyocytes.