bluuebunny/crossref_metadata_2025 huggingface dataset:
Image Principal Distance Calibration Method by Binocular Camera Based on Improved Differential Evolution Algorithm
Authors: Kuang Xiangning , Qiu Faju , Xu Shengyong , Chou Jiajie , Ding Gaoyao
Published: June 2022

The traditional camera calibration method usually relies on the calibration plate, mainly uses the exhaustive method, and converts the spatial coordinates into image plane coordinates by solving the resection of the equation. The accuracy and calculation rate of traditional algorithms can no longer fully meet the needs of engineering applications. In view of this situation, this paper proposes an improved differential evolution algorithm (IDE) method for binocular camera calibration. The differential evolution algorithm (DE) is an algorithm that simulates the biological evolution process and uses the survival of the fittest to gradually screen individuals to find the optimal solution. The standard DE algorithm needs to perform population initialization, mutation operation and crossover operation, and finally screen individuals through greedy algorithm. In the mutation operation of the DE algorithm, the coefficient of variation F plays a crucial role in the result but it is difficult to obtain a value. Therefore, it is necessary to optimize the operator of the coefficient of variation F, so that the coefficient of variation F also reaches the optimal solution, which is the IDE algorithm. In this paper, the traditional calculation method, the standard DE algorithm and the IDE algorithm are used to calibrate the principal distance of the two images, and the accuracy and iteration rate are compared. The experimental results show that the IDE algorithm has obvious advantages in terms of accuracy, especially the calculation speed.
Soybean Variety Identification Based on Improved ResNet18 Hyperspectral Image
Authors: Liu Hongyu , Qu Fuheng , Yang Yong , Li Wanting , Hao Zhonglin
Published: June 2022

Aiming at the problems of insufficient feature extraction, slow speed and low accuracy of traditional machine learning methods, a soybean variety identification method based on improved ResNet18 hyperspectral image was proposed. This method extracts more effective detail features by decomposing the large convolution kernel, and changes the connection of residual structure and introduces the BN layer optimization network to make the feature extraction more sufficient. The perception of soybean hyperspectral image recognition is enhanced by adding multi-scale feature extraction module. The experimental results show that the recognition accuracy of this method reaches 97.36 %, which is higher than Nasnet large and Resnet18 models, and the robustness of the model is further enhanced, which can provide reference for soybean variety recognition.
Small target detection based on point cloud feature learning
Authors: Guo Baicheng , Miao Li , Zhou Shilin
Published: June 2022

Small target detection is an important means of target detection, the photoelectric detector of which mainly uses infrared and visible light band. In many issues, the targets imaging in optical detector can be seen as small targets. Taking the time domain of the single frame detection result of small target motion as the third-dimensional information input, the small target detection can be transformed into the problem of point cloud target detection. The purpose of this paper is to implement a small target detection neural network based on point cloud feature learning.
Numerical simulation and Experimental Verification of Heat Treatment of ISO-CC8X Rivet Nut
Authors: Niu Fangjing , Zhong Shaohua , Yu Le
Published: June 2022

In this paper, the method of finite element analysis is used to study and Simufact.forming software is used to simulate the cold forming process and heat treatment process of ISO-CC8X riveting nut. The changes of equivalent stress of the riveting nut after cold forming process and heat treatment process are obtained. Then, residual stress detection and metallographic experiments were carried out to verify the reliability of the numerical simulation. This method is of guiding significance to the design and optimization of heat treatment process of metal parts in practical production.
Investigation into the Evolution of Unsteady Flow of Lubricating Oil System in Guide Bearing of a Pump Turbine Unit
Authors: Zhang Zheng , Meng Fancong , Zhao Feng , Zheng Kai , Yang Bin , Cheng Yongguang , Zhou Daqing
Published: June 2022

The water-guide bearing lubricating oil system of pumped storage unit is prone to oil dumping and oil spillage during the start-up of the unit, which seriously threatens the safe and stable operation of the unit. In this study, a three-dimensional unsteady numerical simulation is performed to investigate the causes of oil dumping and oil spillage of a water-guide bearing lubricating oil system of a pumped storage power plant unit based on the VOF (volume of fluid) multiphase flow model and Realizable k-ε model. The unsteady flow characteristics inside the rotating oil basin and pump-type Pitot tube during the start-up process are analyzed. The results demonstrate that the change of the external characteristics of the lubricating oil system can be divided into two stages, the initial formation process of the lubricating oil flow and the stable circulation process of the lubricating oil flow. In the initial formation process, the pressure inside the rotating basin is uniformly distributed in the circumferential direction, and a high-pressure zone is generated near the inlet of the pump-type Pitot tube, driving the lubricant flow to the stationary basin above; in the stable flow cycle process, the internal lubricant flow velocity gradually decreases along the radius direction, and a large vortex zone appears behind the pump-type Pitot tube and at the inlet of it. This phenomenon leads to the lubricating oil pressure here to be lower than the saturation vaporization pressure, which may trigger lubricating oil atomization and then overflow from the seal ring. This study is committed to provide theoretical analysis and engineering reference for the investigation of the causes of oil dumping and oil spillage in the lube oil system of water guide bearings of pumped storage units.
Structural analysis of solid rocket motor with effects of viscoelastic Poisson's ratio
Authors: Wang Junqi , Bao Futing , Cui Huiru
Published: June 2022

The new measured viscoelastic Poisson's ratio (VPR) is introduced to investigate the effect of its variation on structure integrity analysis of solid rocket motor. A developed relaxation constitutive model considering VPR is utilized to implement in the finite element code MSC.Marc. Cooling analysis and ignition pressure loading case are designed to analyze the effects along the inner surface of propellant grains. Results show that the little change of the VPR including equilibrium Poisson's ratio (ePR) and reference temperature will affect the output of simulation, and the same up variation of the VPR has relatively less effect on the analysis than the elastic one. Furthermore, the up variation of viscoelastic Poisson ratio will disturb the distribution of strain and stress along the inner surface of propellant grains seriously while the elastic one won’t.
Establishment of constitutive model based on Ogden strain energy storage function and its matching with the mechanical properties of polyurethane dielectrics
Authors: Lu Gang , Shuai Changgeng , Liu Yinsong , Cheng Xiaolin , Hu Xiaoyang , Yang Xue
Published: June 2022

In order to find the constitutive relationship of mechanical properties suitable for polyurethane dielectric elastomer, the constitutive model of dielectric elastomer based on Ogden strain energy storage function was established. Then taking polyether MDI polyurethane as the research object, the first-order, second-order and third-order Ogden constitutive models were fitted by the preparation and mechanical properties test of polyurethane dielectric elastomer with different soft and hard segment contents. It is found that the second-order Ogden constitutive model fits the stress-strain curve of polyurethane dielectric elastomer well, and the highest modified fitting coefficient is as high as 0.9996. At the same time, we found that the fitting effect of the third-order Ogden constitutive model is greatly affected by the soft segment content, and the fitting effect is good when the soft segment content is high, while the fitting effect of the first-order Ogden model is bad. In addition, there is no effect when the drawing rate and shape change. This is because the first-order Ogden model can be simplified into Neo Hooken model and Mooney Rivlin model, which are suitable for the mechanical behavior of small deformation range and have poor fitting for the nonlinear large deformation process of the system.
The newly installed IBIL (Ion Beam Induced Luminescence) set-up at CEDAD-University of Salento: design and first applications on perovskite
Authors: Quarta G. , Caricato A.P. , Provenzano C. , Marra M. , Albanese E. , Vasco G. , Martino M. , Maruccio L. , Calcagnile L.
Published: June 2022

We present the design and implementation of the new Ion Beam Induced Luminescence set-up recently installed and tested at the Centre of Applied Physics, Dating and Diagnostics of the University of Salento. The set-up allows the irradiation of samples at atmospheric pressure with MeV protons produced by a 3 MV Tandetron accelerator and extracted in air through a kapton membrane. Ion beam induced luminescence is collected by an optical fiber and analyzed by an imaging spectrometer. Simultaneously, characteristic X-Rays emitted by the sample are detected by a Silicon Drift Detector (SSD) detector. The system also allows combined photoluminescence measurements by using an excitation laser focused onto the samples.

First applications in the analysis of all-inorganic perovskites (CsPbBr3) deposited by PLD (Pulsed Laser Deposition) are presented.
Data requirements for operating model of harvest strategy for yellowfin tuna fisheries in North Maluku Waters
Authors: Pratiwi Siti Utami , Wiryawan Budy , Simbolon Domu
Published: June 2022

This Study focused on tuna handline fisheries in Morotai Island, North Maluku. Yellowfin tuna fisheries have great potential economic value. However, the high level of exploitation by small-scale fisheries in coastal waters is feared to disrupt the sustainability of tuna resources therefore, a better management approach is needed, known as a harvest strategy, based on the use of appropriate data and a strong operating model. Indonesia’s government initiated to development of the harvest strategies to manage tuna resources within Indonesia’s archipelagic waters (FMAs 713, 714, dan 715) as a priority action of the National Tuna Management Plan (NTMP). The implementation of the strategy requires adequate data and completeness of instruments. This research tried to identify the adequacy and availability of harvest strategy data and determine yellowfin resource status with LB-SPR. The case studies demonstrate the utility of scientific monitoring data to track trends in the abundance of adult fish without requiring complex stock assessment models through gap analysis. The adequate data harvest strategy was used to condition prototype operating models for testing preliminary harvest strategies through better OMs and MSE. The results showed that the adequacy of the HS data had a gap of 1.56 with an adjustable rate of 63% or not up to standard. The level of utilization of yellowfin tuna resources using the SPR method leads to overfishing.
Potential of nanoemulsion process and method using agro-industrial based materials in skincare formulations: A review
Authors: Ali G S , Hambali E , Fahma F
Published: June 2022

Nanoemulsion technology in the skincare production process plays an important role in improving product quality. Nanoemulsion has a small droplet size which increases the ability of the active compounds to penetrate the skin. Nanoemulsion forming components are similar to conventional methods but the dispersed particles and droplets are smaller in size with a diameter of 20-200 nm. Nanoemulsion has been widely applied to skincare products to increase stability and to improve quality. Agro-industrial based nanoemulsions have potential in the formulation of skincare products. A general description of the formulation, process and application of skincare products will be presented in the discussion. The method used consists of two parts, namely the high energy method which includes microfluidization, high pressure homogenization and ultrasonication, while the low energy method consists of phase inversion composition, phase transition temperature, solvent displacement and newly developed approaches such as D phase emulsification. The purpose of this literature study is to discuss the process and methods of skincare nanoemulsion formulations to increase stability, the potential of agro-industrial based material as a nanoemulsion and cover the potential for scale-up.
Influences of zinc chloride on fast pyrolysis of pinewood
Authors: Garrido R A , Reckamp J , Bastian P , Hammer N H , Coe C G , Satrio J A
Published: June 2022

Fast pyrolysis is a thermochemical process which converts biomass into intermediate bio-oil and biochar products, which can be further processed to produce end products. Bio-oil is an organic liquid containing myriads of organic chemicals derived from the decomposition of cellulose, hemicellulose, and lignin components in lignocellulosic biomass. There are chemicals in bio-oil which are highly valuable as specialty chemicals, such as furfural, levoglucosan and levoglucosenone. Unfortunately, the amounts of these chemicals are typically too small, which makes it uneconomical to extract them from bio-oil. This work is focused on fast pyrolysis of pinewood, a well-known softwood used in paper industry. In this work, it was demonstrated that bio-oil containing higher fractions of furfural and levoguclosenone can be produced by treating pinewood feedstock with zinc chloride prior to pyrolysis. The batch pyrolysis studies by using a micropyrolyzer, a batch tubular reactor, and a thermogravimetric analyzer showed that the amounts of zinc chloride impregnated to pinewood feedstock significantly affect the yields of bio-oil and biochar products and the composition of chemicals in bio-oil. Increasing the concentration of zinc chloride solution used for pretreating the feedstock resulted in higher yields of biochar containing higher amount of the salt. Optimum concentrations of furfural and the two sugars in bio-oil product seemed to be obtained from pyrolysis of pinewood that was pretreated with 5wt% zinc chloride solution. Pretreatment with higher salt concentration reduced the concentration of levoglucosan but did not affect the other two valuable chemicals.
Influence of B30 palm-based biodiesel blends upon degradation of elastomers
Authors: Maharani Dewi Solikhah , Wimada Andrias Rahman , Arisanti Anisa Galuh , Karuana Feri , Ghazidin Hafizh , Putra Hanafi Prida , Pratiwi Fatimah Tresna , Restituta Bina Barus
Published: June 2022

The use of biodiesel could affect the characteristic of elastomers. It may cause swelling degradation of strength and hardness of the elastomers. In this research, the influence of B30 palm-based biodiesel blends upon degradation of elastomers was investigated, especially elastomers used in the industrial gasket or seal materials, including ethylene propylene diene monomer (EPDM) and fluoroelastomer. The tests were carried out by immersing the elastomers in static B30 (30% biodiesel in diesel) at room temperature (27 – 30 oC) for 1007 h. The elastomeric strength was tested physically by measuring the swelling of mass and volume, hardness, and tensile strength at the 71, 167, 671, and 1007 h immersion time. The results show that fluoroelastomer has a more negligible degradation effect than ethylene propylene diene monomer (EPDM).
Garland chrysanthemum consumption ameliorates age-related hearing loss in C57BL/6 mouse; model system to explore hearing loss prevention foods in a short period
Authors: Oike Hideaki , Tomita Satoru , Koyano Hitoshi , Azami Kayo
Published: June 2022

Garland chrysanthemum (Glebionis coronaria L.) is an antioxidant-rich leafy vegetable. We found that garland chrysanthemum consumption ameliorated age-related hearing loss (AHL) in C57BL/6J mice, an early onset model. We also found that AHL progression was significantly ameliorated by three of ten products. Metabolome analysis of the 10 products using nuclear magnetic resonance (NMR) spectroscopy indicated that phytosterols may be involved in the amelioration of AHL. However, the direct inhibitory effect of phytosterol mixture on mouse AHL progression was not identified. These results suggest that garland chrysanthemum consumption delays AHL development in mice and its efficiency varies depending on the source of the product. Our findings also suggest that phytosterol content in garland chrysanthemum functions as an evaluation marker for the efficiency. Furthermore, to accelerate the search for foods that prevent AHL, we have used these data to develop an automatic threshold determination method for auditory brainstem response using machine learning.
The continuing evolution of birth cohort studies: achievements and challenges
Authors: Lin Yuan , Jiang Yangqian , Du Jiangbo , Ma Hongxia , Shen Hongbing , Hu Zhibin
Published: June 2022

Well-designed birth cohorts are able to estimate prevalence/distribution of various health events/outcomes, and to link early-life origins with adult health and function. The past two decades have seen a surge in the establishment of new birth cohorts and their accompanying research. We discussed distinct designs of current birth cohort studies, reviewed their achievements, and highlighted insights obtained from birth cohort studies, as well as challenges we are facing. Birth cohort studies are providing increasing opportunities to identify determining factors for short- and long-term health, yielding substantial evidence to uncover biological mechanisms of diseases and phenotypes, and providing further insights for public health. Dynamic monitoring, accurate measurements, long-term follow-ups, and collaborative efforts are warranted in new birth cohorts to elucidate the nature of life course relationships in contemporary generation.
Effects of fish oil-containing nutrition supplementation in adult sepsis patients: a systematic review and meta-analysis
Authors: Wang Hongyu , Su Sen , Wang Chao , Hu Jianhong , Dan Wu , Peng Xi
Published: June 2022

Background

Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection. Although fish oil has been used as an immunonutritional preparations for the treatment of sepsis patients, there is still controversy as to whether it is beneficial to them. We systematically reviewed published clinical trial data to evaluate the effectiveness of fish oil-containing nutrition supplementation in sepsis patients.

Methods

A systematic search was undertaken in PubMed, Embase, Chinese Biomedicine Database, the Cochrane Library and the China Knowledge Resource Integrated Database to obtain clinical controlled trails. RCTs on nutrition therapy containing fish oil among adult sepsis patients were selected for analysis in comparison with routine therapy.

Results

Twenty-five published trials were included in the meta-analysis. Fish oil-containing nutrition supplementation reduced the mortality compared with the control group (relative risk (RR) 0.74, I2 = 0%). Fish oil also shortened the ICU stay (MD −3.57 days; 95% CI −4.54, −2.59; p<0.00001; I2 = 76%), hospital stay (MD −9.92 days; 95% CI −15.37, −4.46; p = 0.0004; I2 = 91%) and the duration of mechanical ventilation support (MD −2.26; 95% CI −4.27, −0.26; p = 0.03; I2 = 83%). A subgroup analysis based on the route of administration revealed that parenteral administration of fish oil could reduce mortality in septic patients (RR =0.68, I2 = 0%), but no significant difference in mortality was observed in the fish oil group administered by enteral route (RR = 0.80, I2 = 0%). No statistically significant publication biases were detected for the above clinical endpoints (p>0.05).

Conclusions

Parenteral nutrition containing fish oil could significantly decrease mortality in sepsis patients while enteral administration could not. Fish oil-containing nutrition supplementation.
Estimation of the Lifetime Quality-Adjusted Life Years (QALYs) Lost Due to Syphilis Acquired in the United States in 2018
Authors: Lee Kyueun , You Shiying , Li Yunfei , Chesson Harrell , Gift Thomas L , Berruti Andrés A , Hsu Katherine , Yaesoubi Reza , Salomon Joshua A , Rönn Minttu
Published: June 2022

Background

The purpose of this study was to estimate the health impact of syphilis in the United States in terms of the number of quality-adjusted life years (QALYs) lost attributable to infections in 2018.

Methods

We developed a Markov model that simulates the natural history and management of syphilis. The model was parameterized by sex and sexual orientation (women who have sex with men, men who have sex with women [MSW], and men who have sex with men [MSM]), and by age at primary infection. We developed a separate decision tree model to quantify health losses due to congenital syphilis. We estimated the average lifetime number of QALYs lost per infection, and the total expected lifetime number of QALYs lost due to syphilis acquired in 2018.

Results

We estimated the average number of discounted lifetime QALYs lost per infection as 0.09 (95% uncertainty interval [UI] .03–.19). The total expected number of QALYs lost due to syphilis acquired in 2018 was 13 349 (5071–31 360). Although per-case loss was the lowest among MSM (0.06), MSM accounted for 47.7% of the overall burden. For each case of congenital syphilis, we estimated 1.79 (1.43–2.16) and 0.06 (.01–.14) QALYs lost in the child and the mother, respectively. We projected 2332 (1871–28 250) and 79 (17–177) QALYs lost for children and mothers, respectively, due to congenital syphilis in 2018.

Conclusions

Syphilis causes substantial health losses in adults and children. Quantifying these health losses in terms of QALYs can inform cost-effectiveness analyses and can facilitate comparisons of the burden of syphilis to that of other diseases.
Immunological, Cognitive, and Psychiatric Outcomes After Initiating Efavirenz- and Dolutegravir-based Antiretroviral Therapy During Acute Human Immunodeficiency Virus Infection
Authors: Chan Phillip , Yoon Bohyung , Colby Donn , Kroon Eugène , Sacdalan Carlo , Sriplienchan Somchai , Pinyakorn Suteeraporn , Ananworanich Jintanat , Valcour Victor , Vasan Sandhya , Hsu Denise , Phanuphak Nittaya , Paul Robert , Spudich Serena
Published: June 2022

Background

Efavirenz (EFV)- and dolutegravir (DTG)-based antiretroviral therapy (ART) is the former and current recommended regimen for treatment-naive individuals with human immunodeficiency virus type 1 (HIV-1). Whether they impact the immunological and neuropsychiatric profile differentially remains unclear.

Methods

This retrospective analysis included 258 participants enrolled during acute HIV-1 infection (AHI). Participants initiated 1 of 3 ART regimens during AHI: EFV-based (n = 131), DTG-based (n = 92), or DTG intensified with maraviroc (DTG/MVC, n = 35). All regimens included 2 nucleoside reverse-transcriptase inhibitors and were maintained for 96 weeks. CD4+ and CD8+ T-cell counts, mood symptoms, and composite score on a 4-test neuropsychological battery (NPZ-4) were compared.

Results

At baseline, the median age was 26 years, 99% were male, and 36% were enrolled during Fiebig stage I–II. Plasma viral suppression at weeks 24 and 96 was similar between the groups. Compared with the EFV group, the DTG group showed greater increments of CD4+ (P < .001) and CD8+ (P = .015) T-cell counts but a similar increment of CD4/CD8 ratio at week 96. NPZ-4 improvement was similar between the 2 groups at week 24 but greater in the DTG group at week 96 (P = .005). Depressive mood and distress symptoms based on the Patient Health Questionnaire and distress thermometer were similar between the 2 groups at follow-up. Findings for the DTG/MVC group were comparable to those for the DTG group vs the EFV group.

Conclusions

Among individuals with AHI, 96 weeks of DTG-based ART was associated with greater increments of CD4+ and CD8+ T-cell counts and improvement in cognitive performance.
Continued Increase of Erythromycin Nonsusceptibility and Clindamycin Nonsusceptibility Among Invasive Group A Streptococci Driven by Genomic Clusters, United States, 2018–2019
Authors: Li Yuan , Rivers Joy , Mathis Saundra , Li Zhongya , McGee Lesley , Chochua Sopio , Metcalf Benjamin J , Fleming-Dutra Katherine E , Nanduri Srinivas A , Beall Bernard
Published: June 2022

We analyzed 9630 invasive GAS surveillance isolates in the USA. From 2015–2017 to 2018–2019, significant increases in erythromycin-nonsusceptibility (18% vs 25%) and clindamycin-nonsusceptibility (17% vs 24%) occurred, driven by rapid expansions of genomic subclones. Prevention and control of clustered infections appear key to containing antimicrobial resistance.
A fast parameter estimator for large complex networks
Authors: Guzman Grover E C , Takahashi Daniel Yasumasa , Fujita André
Published: June 2022

Many natural phenomena are the results of interactions of different components. For example, an organism’s phenotype results from interactions of genes, proteins and the environment. The characteristics of our society are shaped by how people relate to each other. The internet is the product of billions of interconnected computers, electronic devices and users. To understand systems, we represent them using networks, that is, random graphs. A critical inferential step is to estimate the parameters of these networks. Often analytical likelihood estimators for random graph parameters are unknown. In these cases, non-parametric approximations for likelihood estimators can be used. However, known non-parametric estimators for complex network models are computationally inefficient. Here, we present a linear time and space non-parametric estimator for massive networks ($\mathcal{O}(n)$). We show that our method precisely estimates the parameters of networks composed of five million nodes in a few hours. In contrast, a usual approach would need 900 years.
A single cell transcriptional roadmap of human pacemaker cell differentiation
Authors: Wiesinger A , Li J , Fokkert L , Bakker P , Verkerk A , Christoffels V , Boink G , Devalla H
Published: June 2022

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Research council starting grant 714866 and associated proof-of-concept grant 899422

Dutch Heart Foundation Dekker fellowship 2020T023

The sinoatrial node (SAN), the primary pacemaker of the heart generates electrical impulses that set the rhythm of the heartbeat. It is a multicomponent structure composed of "head", "tail" and "transitional" cardiomyocytes as well as proepicardium-derived mesenchymal cells. Previous studies have shown that pacemaker cells of the SAN originate from a common progenitor that also gives rise to the proepicardium. However, little is known of the molecular mechanisms that are implicated in 1) the divergence of pacemaker and proepicardial cells and, 2) the diversification of pacemaker cells into head, tail and transitional cells. Here, we performed single cell RNA sequencing (scRNA-seq) and trajectory inference analysis on human induced pluripotent stem cells (hiPSCs) differentiating to SAN-like cardiomyocytes (SANCM) to construct a roadmap of transcriptional changes and lineage decisions that guide these processes.

scRNA-seq of differentiated cells revealed transcriptionally distinct cardiomyocyte populations that closely resemble different subpopulations of the in vivo SAN, such as "head", "tail" and "transitional" cells. Moreover, we identified a side population of proepicardial cells suggesting their shared ontogeny with SANCM, as also reported in vivo. Reconstruction of transcriptional trajectories revealed that the SANCM and proepicardial lineages diverge early on and that this lineage decision is determined by WNT signaling. Furthermore, we uncovered a role for TGFβ and WNT signaling in differentiation towards transitional and head SANCM subtypes, respectively. Manipulation of the identified signaling pathways enhanced gene expression patterns of the corresponding cell type, confirming their involvement in diversification towards SANCM subtypes.

Our findings provide new insights into the molecular processes involved in human pacemaker cell differentiation, opening new avenues for complex disease modeling in vitro and inform approaches for cell-therapy based regeneration of the SAN.
Small molecule-mediated rapid maturation of human induced pluripotent stem cell derived cardiomyocytes
Authors: Chirico N , Kessler E L , Maas RGC , Fang J , Qin J , Dokter I , Ciccone S , Saric T , Buikema JW , Lei Z , Doevendans P , Sluijter JPG , Van Mil A
Published: June 2022

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): Gravitation Program “Materials Driven Regeneration” by the Netherlands Organization for Scientific Research (RegmedXB #024.003.013) and the Marie Skłodowska-Curie Actions (Grant agreement RESCUE #801540). The EU-funded project BRAV3 (H2020, ID:874827)

Background

Human-induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iPSC-CMs) do not display all hallmarks of mature human primary cardiomyocytes: the ability to use fatty acids as an energy source, high mitochondrial mass, increased nuclei polyploidism, synchronized electrical conduction, and forceful contractions. Instead, their phenotype is similar to immature cardiomyocytes in the late fetal stage. This immaturity represents a bottleneck to their application in 1) disease modeling – as most cardiac (genetic) diseases have a middle-age onset – and 2) clinical use, where integration and functional coupling are key. So far, the mainly used methods to enhance iPSC-CM maturation include prolonged time-in-culture, 3D culture, cyclic mechanical stretch, and electrical stimulation with specialized media. However, these protocols are laborious, costly, and not easily scalable.

Methods

In this study, we developed a simple, low cost, and rapid protocol using two peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A/PGC-1α) activating small molecules: Asiatic Acid (AA) and GW501516 (GW) to promote cardiomyocyte maturity by inducing a metabolic switch to fatty acid utilization and increased mitochondrial biogenesis.

Results

Monolayers of iPSC-CMs were incubated with AA and GW every other day for 10 days resulting in increased expression of fatty acid-metabolism-related genes (5 and 10-fold increase in CPT1B gene expression, respectively), mitochondria biogenesis (protein expression of ATP5A) and fusion (50 and 100-fold increase in OPA1 gene expression, respectively). In addition, AA treated iPSC-CMs responded in the seahorse mitochondria stress test more rapidly to an artificial increase in mitochondrial activity and showed a higher flexibility in substrate utilization in the seahorse stress test. A more mature electrophysiological functionality was shown by increased ion channel gene expression (KCNA4, SCN5A, GJA1, CACNA1C, and SCN1B) and enhanced synchronous contraction in treated samples. Moreover, maturation was further shown by increased sarcomeric gene expression (5 and 7-fold increase in TNNI3 in AA and GW respectively) and nuclear polyploidism (>4N fold 2.16 and 1.48-fold increase in AA and GW respectively).

Conclusions

Collectively, these findings show that AA and GW trigger a metabolic switch and induce extensive maturation of iPSC-CMs, providing a rapid and cost-effective method to obtain iPSC-CMs that more closely resemble their adult counterparts.
Determining the role of uremic toxins on cardiac electrophysiology and pro-arrhythmia during chronic kidney disease
Authors: Van Ham WB , Bossu A , Houtman MJC , Cornelissen CM , Vos MA , Van Veen TAB
Published: June 2022

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Young Talent Programme, CVON RECONNECT

Introduction

Chronic kidney disease (CKD) is represented by a diminished filtration capacity of the kidneys. End stage renal disease patients need dialysis treatment to remove waste and toxins from the circulation. However, endogenously produced uremic toxins (UTs) cannot always be filtered during dialysis. UTs are one of the CKD-related factors already linked to maladaptive and pathophysiological remodeling of the heart. Importantly, 50% of the deaths in dialysis patients is cardiovascular related, with sudden cardiac death predominating. However, the mechanisms responsible still remain poorly understood.

Purpose

To assess the potentially increased pro-arrhythmic risk of pre-identified UTs at clinically relevant concentrations: 1) acutely in isolated adult dog ventricular cardiomyocytes (ADCMs) and human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs), 2) chronically in iPSC-CMs and 3) both conditions in human embryonic kidney (HEK) cells transfected with constructs that generate different ion channels, using optical and manual electrophysiological in vitro approaches.

Methods and results

Using the voltage sensitive membrane dye FluoVolt and manual patch clamp, action potential duration (APD) prolongation, considered as a pro-arrhythmic parameter, was assessed in ADCMs and iPSC-CMs. Acute exposure of indoxyl sulfate (IS), kynurenine (KYN) or kynurenic acid (KYNA) induced no alterations in APD in ADCMs and iPSC-CMs. iPSC-CMs, although having rather immature electrophysiological characteristics, showed significant APD prolongation when exposed chronically (48h) to those UTs.

Manual patch clamp on HEK293 cells was performed to investigate individual ion currents to reveal underlying mechanisms. The repolarizing current IKr, often most sensitive and responsible for APD alterations, was not acutely affected by IS, KYN, or KYNA. However, chronic exposure (48h) to IS or KYNA significantly decreased IKr at clinically relevant concentrations.

Finally, the protein level of the ion channel conducting IKr was determined in HEK293 cells, to further unveil the mechanism behind the effects of UTs on channels conducting IKr. Chronic exposure (48-72h) of the three UTs decreased total ion channel expression at pathological concentrations, which could be responsible for the decreased IKr and prolonged APD.

Conclusion

The results show the proof of concept to identify potentially pro-arrhythmogenic UTs and their mode of action, allowing the provision of a clinically relevant overview of (patho)physiological concentrations of UTs in both acute and chronic exposure.
Functional remodeling of perinuclear mitochondria alters nucleoplasmic Ca2+ signaling in heart failure
Authors: Voglhuber J , Holzer M , Radulovic S , Thai PN , Djalinac N , Matzer I , Wallner M , Bugger H , Zirlik A , Leitinger G , Dedkova EN , Bers DM , Ljubojevic-Holzer S
Published: June 2022

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): BioTechMed-Graz

Mitochondrial dysfunction in cardiomyocytes is a hallmark of heart failure (HF) development. Although initial studies recognized the importance of different mitochondrial subpopulations, there is a striking lack of direct comparison of intrafibrillar (IF) vs. perinuclear (PN) mitochondria during the development of HF.

Here, we use multiple approaches to examine the morphology and functional properties of IF vs. PN mitochondria in pressure overload-induced cardiac remodeling in mice, and in non-failing and failing human cardiomyocytes. We could demonstrate that PN mitochondria from failing cardiomyocytes are more susceptible to changes in mitochondrial membrane potential (ΔΨm), ROS generation and impairment in Ca2+ uptake compared to IF mitochondria at baseline and under physiological stress protocol. We also demonstrated, for the first time, that under normal conditions PN mitochondrial Ca2+ uptake shapes nucleoplasmic Ca2+ transients (CaTs) and prevents nucleoplasmic Ca2+ overload. Loss of PN mitochondria Ca2+ buffering capacity translates into increased nucleoplasmic CaTs and may explain disproportionate rise in nucleoplasmic [Ca2+] in failing cardiomyocytes at increased stimulation frequencies. Therefore, a previously unidentified benefit of restoring the mitochondrial Ca2+ uptake may be normalization of nuclear Ca2+ signaling and alleviation of altered excitation-transcription, which could be an important therapeutic approach to prevent adverse cardiac remodeling.
Cardiomyocytes (CM) derived small Extracellular Vesicles (sEV) plays an important role in heart development
Authors: Balbi C , Ceresa D , Schiano C , Malatesta P , Barile L , Vassalli G
Published: June 2022

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Schweizerische Herzstiftung - FF21017

Fondazione Leonardo

Introduction

Neonatal rats have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. Cardiac maturation lays the foundation for postnatal heart development and disease, yet little is known about the contributions of the microenvironment to cardiomyocyte maturation.

Extracellular vesicles (EV) are bilayer-membrane nanoparticles released by all cell types, carrying proteins, lipids, and nucleic acids, which reflect the activation state of parental cells. Secreted small extracellular vesicles (sEV), prominently figure among extracellular signals that regulate cell function.

Purpose

We aim to determine whether cardiomyocyte (CM) derived sEV carried miRNA that has a role in heart development with specific regards to cardiomyocyte maturation.

Methods

sEV were isolated from rat cardiomyocyte at day 0 and 7 after birth by serial ultracentrifugation. sEV were characterized by NTA and analyzed by Western blot for the presence of classical EV markers (TSG101, Syntenin-1). The role of sEV in cardiomyocyte proliferation was assesed by analysis of EdU incorporation on neoantal rat CM treated with sEV_p0 or sEV_p7. miRNA content on sEV was assesed using a rat-miRNome MicroRNA Profiling Kit and the identified miRNA's targets confirmed by RealTime-PCR and Western Blot.

Results

NTA and Western Blot analysis confirmed the presence of sEV in both the extracellular vesicles preparation. sEV_p0 showed to be able to sligtly increase EdU incorporation in treated cardiomyocyte (1.15-Fold) while sEV_p7 significantly inihibit CM proliferation (0.78-Fold) toghether with a change in cardiomyocyte citoscheletal architecture. Data from miRNome analysis showed in sEV_p7 a significan increase in miRNA with cyclines as tagets. Downregulation of Cdk1 ; Cdk4 ; Cdk2 ; CcnB1 and CcnD1 was confirmed on CM trated with sEV_p7 compared to Ctrl. Downregulation of CCND1 was aslo confrmed at the protein level by Western Blot analysis.

Conclusions

These preliminary resultes showed an important role in heart develompent of cardiomyocyte derived-sEV. A deeper investigation of the pathaway activated by sEV may have a potential interest for the identification of possible regulators for stimulating heart regeneration.
Re-activation of HIF signalling pathway in the epicardium improves heart regeneration after myocardial infarction
Authors: Gamen E , Price EL , Pezzolla D , De Villiers C , Gunadasa-Rohling M , Salama R , Mole DR , Bishop T , Pugh CW , Choudhury RP , Carr CA , Vieira JM , Riley PR
Published: June 2022

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Background

In mouse, cardiac regenerative capacity is maintained for the first week after birth but lost thereafter. Reactivation of this process holds great therapeutic potential, however, the molecular pathways that might be targeted to extend neonatal regeneration remain elusive. Here, we explore a role for hypoxia inducible factor (HIF) family of transcription factors on the regulation of epicardial activity which is essential for cardiac response to injury.

Purpose

HIF signalling might be involved in the quiescence of the epicardium observed in the first week of life. Thus, HIF stabilisation may induce epicardial re-activation and extend the 7-day regenerative window in a neonate mouse model of myocardial infarction (MI).

Methods

We analysed epicardial expression of HIF signalling during embryonic development, and in a regenerative post-natal day 1 (P1) versus non-regenerative (P7) mouse model by single cell RNA-sequencing. Next, we established in vitro epicardial explants to confirm the role of HIF signalling in epicardial activation, and finally we induced MI by permanent ligation of the proximal left anterior descending (LAD) coronary artery in P7 mice to test weather HIF signalling re-activation improved heart regeneration in a non-regenerative model.

Results

Expression of both HIF-1α and HIF-2α is very pronounced at early stages of heart development and gradually decreases throughout gestation. The epicardium preferentially expresses HIF-1α by embryonic day (E) 16.5. Postnatally, GO term analysis showed an enrichment of hypoxia-related pathways in P1 compared to P7 hearts, largely in the epicardial cell population. Accordingly, expression of Phd2, encoding for the main suppressor of HIF signalling, was enriched in P7 derived epicardial cells. Notably, the increase in Phd2 levels coincided with a clear reduction in the expression of Wilms’ tumour 1 (Wt1) in P7 versus P1 hearts, a key player in the epicardial activation. In vitro studies on epicardial explants confirmed regulation of WT1 expression and migration capacity following genetical and pharmacological modulation of HIF signalling. Finally, in vivo targeting of PHD enzymes through pharmacological inhibition with clinically approved drugs in a neonatal mouse model of MI led to prolonged epicardial activation, increased vascularisation, augmented infarct resolution and preserved cardiac function up to 3 weeks after injury.

Conclusions

Together, these findings show that modulation of HIF signalling can regulate epicardial activity and improve heart regeneration capacity beyond the 7-day regenerative window and may represent a viable therapeutic strategy for treating ischaemic heart disease.
Cardiac remodeling in severe hypertension, does it respond to tight blood pressure control?
Authors: El Tahlawi M , Salem S , Fahmy M , Tharwat M
Published: June 2022

Funding Acknowledgements

Type of funding sources: None.

Background

Severe hypertension (HTN) may cause target organ damage (TOD). Kidney can tolerate severe HTN to very high levels. Cardiac remodeling as TOD could be detected by elevation of biomarker Troponin.

Aim

We aim to detect the response of organs (heart & kidney) to tight control of severe HTN.

Patients & Methods

Patients admitted due to severe hypertension (BP> 180/120) associated with any symptoms were enrolled. All patients were managed according to the European guidelines to the target BP. Cardiac biomarker Hs-Troponin T (hs-TNT) and serum creatinine (s.creat) were measured for all patients on admission and 24 hours later.

Results

Ninty five patients with hypertensive crisis were treated to target BP. Forty six patients had initially high hs-TNT (Group A) and 49 patients had initially normal hs-TNT (Group B). There was a highly significant difference between both groups regarding initial and follow-up s.creat with higher values in Group B (P= 0.03 and 0.004 respectively).There was high significant difference between initial and follow up s.creat values in Group B with higher values in the follow up measurements after BP control to the target (P= 0.03), while this difference is insignificant in Group A (P=0.26).  Five patients in Group B developed renal failure after tight BP control. There was a significant positive correlation between hs-TNT and the follow-up s.creat (P=0.018) with more deterioration of s.creat in those having initial high hs-TNT.

Conclusion

In severe HTN, hs-TNT may be elevated due to marked afterload. Renal affection and TOD occurs before cardiac remodeling and damage due to severe HTN. Renal autoregulation occurs in chronic elevation of BP. Acute control of severe HTN leads to disrruption of renal autoregulation and renal shut down. European guidelines regarding severe HTN control should be revised. In hypertensive patients with high hs-TNT, BP should not be well controlled on the short term not to disrupt renal autoregulation.
Crucial functions of alpha-actinin 2 in the embryonic heart
Authors: Gehmlich K , Jiang A , Wadmore K , Hooper C , Douglas G , Ehler E , Broadway-Stringer S , Kalisch-Smith J , Sparrow D , Gautel M , Davies B , Watkins H
Published: June 2022

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Wellcome Trust; British Heart Foundation

Background/Introduction

Alpha-actinin is an integral protein of the Z-discs in heart and skeletal muscle cells, with important structural and signalling functions.  Missense variants in alpha-actinin can cause inherited conditions, e.g. myopathies and cardiomyopathies. The underlying disease mechanisms are still unknown.

Purpose

In order to study the disease mechanisms of an alpha-actinin missense variant, which is known to cause Hypertrophic Cardiomyopathy in human patients, a mouse model was generated.

Methods

Mice carrying the alpha-actinin missense variant were generated by CRISPR-Cas9 genome editing. The heterozygous adult mice carrying the alpha-actinin variant were characterised by echocardiography and quantitative PCR. Hearts of homozygous embryos were analysed at E15.5 by high-resolution episcopic microscopy (HREM).

Results

Mice carrying a single copy of the missense variant were viable and had normal appearance. Adult heterozygous mice showed no signs of cardiomyopathy on echocardiography. However, mature male mice displayed molecular signs of cardiomyopathy, such as induction of the fetal gene programme at transcript level.

The attempt to generate adult mice homozygous for the variant failed: 9 breeding pairs produced 18 litters with 83 weaned pups, but no homozygous offspring. Embryonic lethality was confirmed and E15.5 was the latest stage homozygous pups were reliably found to be viable. At this timepoint, genotype distribution was within the expected Mendelian ratios.

HREM of the hearts at this stage revealed increased right ventricular chamber size and decreased left atrial size, when compared to wildtype littermates. Membranous ventricular septal defects were observed in 3 out of 8 homozygous hearts. Further these embryos displayed aortic stenosis and dysplasic leaflets of the pulmonary valve.

Conclusions

Heterozygous adult mice only displayed sub-clinical signs of disease. In contrast, the missense variant is embryonic lethal in the homozygous setting and leads to a range of morphological abnormalities in E15.5 hearts. Future work will identify how altered functions of alpha-actinin cause these changes.