bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano crystalline Sr6Sb4NbO18-Energy Material in Solid Oxide Fuel Cells
Authors: John Fergy , Shemim S S , Rinu Sam S
Published: April 2021

Because of the technological applications, Niobium based ceramic is one of the most research interest. Thus, there is numerous research works in recent years on their application as electronic and optical devices. Sintered oxide ceramics, having the required shape, micro structured size can be used for different electronic applications. In this paper, nano crystalline Sr6Sb4NbO18 ceramic was prepared by combustion method. The sample was analysed by the X-ray diffraction, TEM, radio frequency and Impedance spectroscopic studies. The XRD pattern of as prepared Sr6Sb4NbO18 sample reveals, the material has rhombohedral perovskite structure. All the peaks were broad when compared with the bulk, which indicates the reduction in the crystallite size. This is due to the micro strain and nano size in the crystallites. The crystallite size has been calculated from the XRD data, using Scherrer formula and it was obtained as 21 nm. The surface morphology of as prepared sample was studied using TEM and the particle size was found to be 19 nm. The sample was sintered at 1050 °C, obtained the 98 % of theoretical density. An impedance spectroscopic study of the sample carried out with a temperature range of, 200 °C to 500 °C shows that the ions are the main source for the conduction. The reason for the conductivity of the material might be because of the grain and grain boundary effects which can be clearly seen in the impedance plot. The impedance study confirms that the material is a possible candidate to fabricate solid oxide fuel cell.
Influence of Cavity Materials and Selective Surface Coatings on the Performance of SCC
Authors: Lakshmipathy. B#  , Senthil kumar. M  , Sivakumar. K  , Kajavali. A
Published: April 2021

It is evident that the future energy demand can be compensated by using solar energy. The technological improvements are needed to trap the sunlight and have to be utilized in an efficient way. It mainly depends on the type of material which is to be used for this purpose. Solar energy can be effectively captured and utilized to heat the heat transfer fluids. Therefore the usage of solar energy is a right choice as it has the ample availability in countries like India.Solar cavity collector [SCC] is a kind of improvised, modified and redesigned construction of a solar Flat Plate Collector (FPC). In short, SCC is an upgraded and advanced version of FPC. A Copper pipe has been positioned concentrically fitted to a radius (outer) of 16 mm and placed into a metal box like structure having a size of 50 mm. In a similar way, five numbers of such cavities are formed. It has a provision for inlet and outlet water pipes. It has been designed, fabricated and experimented for its optimized level of performance. This paper explains about the usage of materials and solar selective surface coatings that are applicable to Solar Cavity Collector (SCC). The following experimental modifications are carried out in the SCC which are 1.Reciever materials of the SCC have been changed as aluminum and copper. 2. Cavity materials as Galvanized Iron (G.I) material and Mild Steel (M.S) material, both are experimented. 3. Solar selective coatings (SSC) of Black nickel have been used in SCC for the heat transfer improvement.
Strength Characteristics of Concrete by Partial Replacement of Coarse Aggregate with Coconut Shells & Cement with Glass Powder
Authors: Naidu Gopu Ganesh , Babu Nettikoppula Ramesh , Ravikumar Pappula
Published: April 2021

In this study coarse aggregates and cement are partially replaced in the concrete with similar materials like coconut shells and glass powder. While production of the cement there is a lot of pollution to the environment and which causes health issues to the society. In the same way while production of the course aggregates which releases lot of dust into the atmosphere which causes damage to human lives. We can obtain some advantages by partially replacing the coarse aggregates and cement in the concrete. As we all know that the Cement and the coarse aggregates are the main ingredients in the concrete. The cost of these materials is getting increased day by day. There are some of the materials proposed by many researchers to lesser the cost of the concrete and to improve the strength characteristics of the concrete. For coarse aggregates, the coconut shell is the most preferable and it has more potential to the partial replacement of the coarse aggregates in concrete. As well as there is a similar material which used to partially replacement of the cement is waste glass powder. As we observe at many places there is a lot of wastage of glass will produce throughout the year. Mainly glass is the composition of silica. When the glass is crushed into very small size as powder it experienced to the pozzolanic reactions with hydrates in the cement, and calcium silicate hydrate will be formed. The main aim of this research is utilization of the waste material in the concrete as well as decreasing the cost of the construction by using these waste materials in the concrete, by performing all these things we can easily reduce the pollution of the environment and clean the environment by using these waste materials in the concrete..
Molecular Dynamics Simulation of the Tensile Properties of an Al6063-SiO2 Composite under Varying Temperature Conditions
Authors: Idusuyi N , Adekoya A H , Olugasa T T
Published: April 2021

The tensile stress behaviour of Aluminium Metal Matrix Composites (AMCs) reinforced with SiO2 was evaluated using Molecular Dynamics (MD). A cubic model was used for the simulation, while the Modified Embedded Atom Method (MEAM) was implemented to describe the atomic interactions for the MD simulation. From the MD simulation the presence of the SiO2 was found to substantially disrupt the FCC crystallography of the Al and reduce the ductility of the Al while substantially increasing the yield strength of the composite. A Maximum Elastic modulus of 43.3GPa was obtained at a temperature of 350K and 10wt% SiO2.
An Interpretation of Performance and Emission Outcomes of the Compression Ignition Engine using Palm Oil Biodiesel-Diesel Blends
Authors: Kamitkar Nitin Dattatreya , Satishkumar  , Basavaraju A N , Kushnoore Shashikant , Deepa A B , Marimuthu P , Chakravarthy Kalyan N S
Published: April 2021

Research on alternative sources to replace fossil fuels has been started decades ago and still an uninterrupted process. Partial replacement rather than complete is justified with real-time applications. In this research, engine outcomes based on palm oil biodiesel blends are elaborated. The transesterification processed biodiesel from raw palm oil is used to run the engine with a blend proportion of P10D90 and P20D80. From the results obtained, the performance of an engine was degraded with an increase in biodiesel proportion and consumes higher fuel. At lower load diesel and P10D90 have almost equal thermal efficiency whereas at peak load it is found that 39.1% and 37.6% respectively. Apart from CO emissions, there is an increment in CO2, HC, and NOX with the load. NOx emissions are in the margin with diesel for P10D90 at part load. P10D90 shown slightly lower in-cylinder pressure at full load compared to diesel.However, it is seen that P20D80 has given depreciated performance readings, lowered cylinder pressure 55.8 bar, and higher emissions at rated torque. From the experiment, it is noticed that above 10% of the biodiesel blend engine required suitable modifications and accessories to overcome demerits associated with blend characteristics.
Effect of Nitrogen Dopant on Electrical Resistance of Hot Zone of SiC Heating Elements
Authors: Kavitha S D , Kulakarni N Suneel Kumar , Suresh R , Shivanna D M
Published: April 2021

In the present work gaseous nitrogen is used as dopant in silicon carbide heating element to study the effect of electrical resistance in heat generation portion of heating elements. The silicon carbide heating elements are used mainly in non-ferrous alloy melting and holding furnaces in automotive and aerospace industrial applications. The gaseous nitrogen plays a major role as dopant in achieving the electrical resistance of SiC heating elements. The green silicon carbide is used to prepare the heating element by powder metallurgy process because of its high mechanical strength, resistance to corrosion, and high thermal conductivity at elevated temperature. However, the nitrogen acts as dopant in silicon carbide to achieve the electrical resistivity in the heating element to generate uniform heat in hot zone portion of SiC heating elements while sintering. The hot zone of SiC heating element is connected with cold zone at both the terminals of heating element to pass the current to hot zone to generate the heat by its higher resistivity. A range of nitrogen gas flow rate ranges from76 lt/hr to 84 lt/hr with 99.99% purity of industrial grade passed to the sintering furnace, in turn it acts as dopant and creates inert atmosphere in the sintering furnace, then the SiC heating element tubes were made and analysed. The results indicate that the quantity of gaseous nitrogen dopant influenced the electrical resistivity of the heat generating portion of SiC heating element.
Investigation of engine characteristics of a variable compression ratio diesel engine using biodiesel and alcohol blends
Authors: Taneja Sumit , Singh Princepreet
Published: April 2021

Increasing environmental pollution and reducing fossil fuels are major concerns of today’s age. To address both the above said issues, the present research focuses on fossil fuel compensation with Biofuels additives. The objective is to analyze combined effect of biodiesel, alcohols and other additives on the diesel engine performance and emission characteristics. The prime target of present research is to analyze the emission characteristics of the diesel engine fueled with Biodiesel (20%)-diesel, Biodiesel (20%)-ethanol (10%)-diesel and Biodiesel (20%)-butanol (10%)-diesel blends. For this purpose, various loads and compression ratios have been applied on each of the blends, to get the optimum result for better performance and reduction in emissions. Engine tests were conducted at variable loads, starting from no load (0 Kg) to full load (15 Kg) at rpm of 1500 on a single cylinder diesel engine. Two compression ratios CR16 and CR18 were used for the research. Engine performance parameters namely BSFC, BTE and engine emissions namely NOX, CO, HC and CO2 were measured. Performance and emission variations of the modified blends were compared with the reference fuel (pure diesel) for the quantitative assessment of the improvements.
Optimization of Extraction Process of Jatropha Oil by Using Quenching Agent
Authors: Kothari Richa , Ahmad Shamshad , Samykano M , Tyagi V.V. , Pandey A K , Saidur R.
Published: April 2021

Among the various energy plant species, Jatropha curcus is found to be best oil-bearing plant species with a wide range of applications and having enormous economic potentials for its seed, which can be converted into biodiesel via transesterification which is an alternative to petrodiesel. In this present study, the effect of three factors, Time (1-4 hour), temperature (60-120°C) and quenching agents (NaCl, KCl, and ZrCl2) and dose of quenching agent(0.5-2gm) use for the extraction of oil from 10grm of jatropha seed. Using the Box-Benken Design (BBD) approach of Response Surface Methodology (RSM), 17 experimental runs were generated. n-Hexane was used as solvent for each experiment carried out in the 100 ml soxhlet extraction apparatus. Results obtained from the experiments were modeled and analyzed by choosing a quadratic model. From the analysis of modeled found temperature extraction time and dose of quenching agent revealed the good agreement of value (R2=0.98) between observed and predicted value of the experiment and were to be p>0.05 that was based on 95% confidence interval. By the use of RSM-BBD an optimizing experiment 60°C temperature 3h time and 2gm ZrCl2 quenching agent give best extraction of oil yield 41.41%.
Development of Eutectic Phase Change Materials for Solar Thermal Energy Storage
Authors: Sharma R. K. , Ansu A. K. , Laiker U.
Published: April 2021

This paper presents the findings on preparation and thermal analysis of binary eutectic mixture of polyethylene glycol 2000 and 6000. Their measured latent heat are 165.3 J/g and 220 J/g respectively. Eutectic mixtures of these materials were prepared by weight percentage composition with an increment of 10% i.e. compositions of PEG 2000 : PEG 6000 with 0:100, 10:90, 20:80 and so on till 100:0 were prepared. The thermal properties, melting temperatures and latent heats of fusion of these mixtures were measured by DSC analysis. The eutectic mixture with 50:50 composition was kept in a thermal cycling test rig to perform an accelerated thermal cycle test up to 1500 cycles. The melting temperature and latent heat of fusion of this thermally cycled mixture were obtained by DSC analysis on 0th, 100th, 500th, 1000th and 1500th cycle. There was a drop of 1.9 °C in the melting temperature and 8% degradation in latent heat of fusion was observed in comparison to 0th cycle. Considering these values it can be deduced that the eutectic mixture is thermally stable.
Dissemination of Sustainable Cooking: A Detailed Review on Solar Cooking System
Authors: Singh Hemant Raj , Sharma Dilip , Soni Shyam Lal
Published: April 2021

Cooking sector is considered as one of the major energy consuming sector in developing and underdeveloped countries. From the primitive age, humankind largely rely on biomass for their cooking energy need, even though there has been a tremendous upgradation in cooking methods. Due to hazardous effects and energy inefficiencies of conventional biomass cooking system, unconventional cooking energy (method) is becoming popular day by day. Dependency on ever depleting fossil fuel has forced us to switchover to renewable energy options and amongst all; solar energy seems best option due to its inherent reasons. In this study, efforts have been made to review the entire solar cooking systems incorporating with and without thermal energy storage available hitherto. The study reveals the different thermal performance parameters of solar cooking system and attempts to highlight the adaption factors of solar cooking system in the designated market.
Simulation Analysis for Induction Motor Drive Fault Detection and Localization Under Variable Load and Speed Operation
Authors: Yaacob Sazali , Rasyadan Amir , Krishnanf Pranesh
Published: April 2021

The induction motors are widely used in the industry for their advantage of being reliable, rugged, and simple in construction. Nonetheless, the use of inverter-based drives has increased the overall system failure possibility mainly because of the power electronics switches used in the inverter itself. For that reason, it is crucial to monitor the inverter switches health during operation to avoid total system breakdown. A method to do so is by using the current vector trajectory analysis on the induction motor stator current signal. However, one disadvantage of using this method is that it is negatively affected by the load and speed variations. This paper is intended to discuss further on the matter and look into the methods that can be used to minimize the effects associated with the load and speed variations using computer simulation analysis.
Feasibility Analysis of Solar Power Generation System for Office Building in Academic Institution
Authors: Mohd Zublie Muhammad Firdaus , Hasanuzzaman Md. , Rahim Nasrudin Abd.
Published: April 2021

This paper study the potential of energy-saving through lighting located at the office building in an academic institution known as Politeknik Sultan Azlan Shah (PSAS). Exercise through energy audit has been conducted at 3 main academic building to identify energy usage of lighting. 3 academic building involved is Mechanical Engineering Department (MED), Civil Engineering Department (CED), and the Electrical Engineering Department (EED). This study analysis 5 types of lighting to identify which types of lighting use the highest amount of energy in academic buildings. The 5 types of lighting involved in this study are Fluorescent T8 36W, Fluorescent T8 18W, Compact Fluorescent (CFL) 24W, Metal halide (MH) 400W and Ttube 18W. Energy savings are calculated based on the installation of hybrid solar in 3 related buildings. From an energy audit, the energy-saving at-least 5% from previous data has been estimated through the installation of a solar photovoltaic (PV) system. Through feasibility analysis, it is found that energy-saving potential obtained in the year 2019 for MED, CED and EED are about 4299 kWh, 2,319 kWh and 3,269 kWh respectively. Besides, the energy bill saving obtained is about RM 1,569, RM 846 and RM 3,269 respectively for MED, CED, and EED.
Mechanical properties, fracture morphology and thermal analysis of untreated and alkaline treated salago fiber epoxy laminated composites
Authors: Lopena Jerome D , Millare Jeremiah C
Published: April 2021

Natural fibers gain acceptance in various applications due to their advantages over synthetic materials especially in terms of environmental impact, lightweight feature, availability and cost. Apparently, a natural fiber that still needs further exploration on its use in composite is salago. In this study, untreated and alkaline treated salago fiber with varying number of layers from one to three sheets were reinforced in epoxy resin. FTIR analysis and optical microscopy were used to analyze the effect of 5 wt. % sodium hydroxide treatment on the fiber sheets. On the other hand, the composites were subjected to tensile, flexural and Izod impact tests. Tensile fracture morphology was observed through FESEM while thermal degradation was evaluated using thermogravimetric-differential thermal analysis. As compared to neat epoxy, improvements on tensile (52.8%), flexural (37.6%) and impact (more than 6 times) strengths were obtained for the composite with three layers of untreated fiber sheets. Generally, the mechanical properties of the composites improved as the fiber sheets increases. However, the alkaline treated fiber composites obtained lower strengths than their untreated counterparts which may be associated to the presence of holes on the fiber sheets caused by the chemical treatment. Nevertheless, enhancements on moduli and thermal stability were still achieved for the composites with treated fibers which could be related to the good fiber-matrix adhesion caused by the partial removal of hemicellulose and lignin. Moreover, the composite can be used in applications that require high impact strength and stiffness like frame for drones or robots.
Actomyosin dynamics modulate microtubule deformation and growth during T-cell activation
Authors: Rey-Suarez Ivan , Rogers Nate , Kerr Sarah , Shroff Hari , Upadhyaya Arpita
Published: April 2021

Cytoskeletal dynamics plays a critical role in T-cell activation. We show that distinct actomyosin networks at the T-cell immune synapse differentially modulate microtubule growth rates and filament deformation. This indicates that mechanical coupling between these cytoskeletal systems is required for the organization of the immune synapse.
In pancreatic β-cells myosin 1b regulates glucose-stimulated insulin secretion by modulating an early step in insulin granule trafficking from the Golgi
Authors: Tokuo Hiroshi , Komaba Shigeru , Coluccio Lynne M.
Published: April 2021

In pancreatic β-cells, Myo1b controls glucose-stimulated insulin secretion at least in part by mediating an early stage in insulin granule trafficking from the trans-Golgi network.
Outcomes and Complications of Surgical Removal of Foreign Body Granulomas Due to Illicit Polymer Injection for Cosmetic Purposes
Authors: López-Mendoza Francisco J , Moran-Romero Mario , Mouneu Nicole
Published: April 2021

Background

Subcutaneous injection of illicit polymers can result in a number of local complications, including injection-site deformity, granulomas, and skin changes.

Objectives

The aim of this study was to compare postoperative complications and symptom flare in patients undergoing surgical excision of foreign-body granulomas.

Methods

We retrospectively examined data of patients who underwent surgical removal of foreign-body granulomas caused by polymer injection for cosmetic purposes. The granulomas were removed by ultrasonic-assisted liposuction or en bloc excision with primary closure, skin grafts, or free flaps during 2014 to 2020. Data collected included demographic and operative parameters. Postoperative complications, symptom flare, and time to flare were reported. The relations between type of surgery and complications, symptom flare, and time to flare were determined through statistical analysis.

Results

The final cohort included 49 surgeries (42 primary and 7 secondary) in 35 patients. The overall complication rate was 28.9%, with no significant intergroup differences (30.8%, 20%, 66.7%, and 40%; P = 0.328). Wound dehiscence and skin burns were the main complications. An overall symptom flare of 35.1% in surgically treated areas over a mean period of 28.49 months was reported. Chi-squared test indicated statistical significance between type of surgery and symptom flare (P = 0.004) and between complications and flare (P = 0.013). Kaplan-Meier test for flare was statistically significant (P = 0.006) after comparison of the 4 groups.

Conclusions

The rate of postoperative complications was similar for each type of surgery. However, en bloc excision and reconstruction by either primary closure or free flap was associated with a significantly decreased rate of symptom flare and a longer symptom-free period.

Level of Evidence: 4
SysMod: the ISCB community for data-driven computational modelling and multi-scale analysis of biological systems
Authors: Dräger Andreas , Helikar Tomáš , Barberis Matteo , Birtwistle Marc , Calzone Laurence , Chaouiya Claudine , Hasenauer Jan , Karr Jonathan R , Niarakis Anna , Rodríguez Martínez María , Saez-Rodriguez Julio , Thakar Juilee
Published: April 2021

Computational models of biological systems can exploit a broad range of rapidly developing approaches, including novel experimental approaches, bioinformatics data analysis, emerging modelling paradigms, data standards and algorithms. A discussion about the most recent advances among experts from various domains is crucial to foster data-driven computational modelling and its growing use in assessing and predicting the behaviour of biological systems. Intending to encourage the development of tools, approaches and predictive models, and to deepen our understanding of biological systems, the Community of Special Interest (COSI) was launched in Computational Modelling of Biological Systems (SysMod) in 2016. SysMod’s main activity is an annual meeting at the Intelligent Systems for Molecular Biology (ISMB) conference, which brings together computer scientists, biologists, mathematicians, engineers, computational and systems biologists. In the five years since its inception, SysMod has evolved into a dynamic and expanding community, as the increasing number of contributions and participants illustrate. SysMod maintains several online resources to facilitate interaction among the community members, including an online forum, a calendar of relevant meetings and a YouTube channel with talks and lectures of interest for the modelling community. For more than half a decade, the growing interest in computational systems modelling and multi-scale data integration has inspired and supported the SysMod community. Its members get progressively more involved and actively contribute to the annual COSI meeting and several related community workshops and meetings, focusing on specific topics, including particular techniques for computational modelling or standardisation efforts.
Associations of Taste Perception with Tobacco Smoking, Marijuana Use, and Weight Status in the National Health and Nutrition Examination Survey
Authors: Chao Ariana M , Zhou Yingjie , Franks Alexis T , Brooks Brianna E , Joseph Paule V
Published: April 2021

Habitual smoking of tobacco and marijuana can lead to weight changes and poor diet quality. These effects may be caused by taste changes related to smoking and marijuana use. This study examined the associations among taste perceptions of a bitterant (quinine) and salt, tobacco and marijuana use, and weight status. We conducted a cross-sectional analysis of adults who responded to the National Health and Nutrition Examination Survey in 2013–2014. Participants (n = 2808; female = 51.7%) were adults ≥40 years with an average body mass index (BMI) of 29.6 kg/m2. Participants completed whole mouth and tongue tip assessments of bitter (quinine) and salty (NaCl) tastes, and questionnaires on demographics, cigarette, tobacco, and drug use. Measured height and weight were used to calculate BMI. Compared with never smokers, current smokers reported increased bitter ratings. Smoking status was not associated with salty taste intensity ratings after adjustment for demographic variables. Current marijuana users reported lower tongue tip quine ratings than never users. Among current smokers, current marijuana users had lower whole mouth quinine ratings than never users. Taste perception for salt and quinine for current and former smokers as well as marijuana smokers varied in whole mouth and tongue tip assessment. Changes in taste perception among cigarette smokers and marijuana consumers may be clinically relevant to address to improve diet and weight status.
A Simple Bioanalytical Method for Simultaneous Estimation of Amlodipine and Celecoxib in Rat Plasma by High Performance Liquid Chromatography
Authors: Maneesh M U , Ahmed Syed Sagheer , Pasha T Yunus , Ramesh B , Majumder Manish
Published: April 2021

A simple, precise, rapid and accurate UFLC method has been developed with due validation for the simultaneous estimation of Amlodipine besylate and Celecoxib in rat plasma. The separation has been taken place by C18 Eclipse plus column at 1ml/min flow rate. The mobile phase comprises of 20 mM sodium acetate buffer of pH 4.5 adjusted with glacial acetic acid and methanol (30:70% v/v). The effluents were monitored at 228 nm with a total run time of 15min. The retention time of Amlodipine besylate and celecoxib were found to be 7.69 min and 10.69 min respectively. The extraction of drugs have been achieved by protein precipitation technique with methanol as a solvent. The detection concentration was linear over 60–420 ng/ml for Amlodipine besylate and 600-4200 ng/ml for Celecoxib. Regression equation of Amlodipine besylate and Celecoxib were found to be y = 30.996x + 520.29 & y = 39.722x + 23706 with regression coefficient 0.9944 & 0.9941 respectively using unweighted and weighted linear regression with a weighting factor of 1/x0, 1/x, 1/✓x and 1/x2. The percentage recoveries were found to be 88.52±1.276 to 93.06±2.872 for Amlodipine & 89.40±0.728 to 94.05±0.221 for Celecoxib. This liquid chromatography method was extensively validated for linearity, accuracy precision, and stability studies.
Dynamic nature of the LVOT following transcatheter mitral valve replacement with LAMPOON: new insights from post-procedure imaging
Authors: Kohli Keshav , Wei Zhenglun Alan , Sadri Vahid , Khan Jaffar M , Lisko John C , Netto Tiffany , Greenbaum Adam B , Blanke Philipp , Oshinski John N , Lederman Robert J , Yoganathan Ajit P , Babaliaros Vasilis C
Published: April 2021

Aims

To characterize the dynamic nature of the left ventricular outflow tract (LVOT) geometry and flow rate in patients following transcatheter mitral valve replacement (TMVR) with anterior leaflet laceration (LAMPOON) and derive insights to help guide future patient selection.

Methods and results

Time-resolved LVOT geometry and haemodynamics were analysed with post-procedure computed tomography and echocardiography in subjects (N = 19) from the LAMPOON investigational device exemption trial. A novel post hoc definition for LVOT obstruction was employed to account for systolic flow rate and quality of life improvement [obstruction was defined as LVOT gradient >30 mmHg or LVOT effective orifice area (EOA) ≤1.15 cm2]. The neo-LVOT and skirt neo-LVOT were observed to vary substantially in area throughout systole (64 ± 27% and 25 ± 14% change in area, respectively). The peak systolic flow rate occurred most commonly just prior to mid-systole, while minimum neo-LVOT (and skirt neo-LVOT) area occurred most commonly in early-diastole. Subjects with LVOT obstruction (n = 5) had smaller skirt neo-LVOT values across systole. Optimal thresholds for skirt neo-LVOT area were phase-specific (260, 210, 200, and 180 mm2 for early-systole, peak flow, mid-systole, and end-systole, respectively).

Conclusion

The LVOT geometry and flow rate exhibit dynamic characteristics following TMVR with LAMPOON. Subjects with LVOT obstruction had smaller skirt neo-LVOT areas across systole. The authors recommend the use of phase-specific threshold values for skirt neo-LVOT area to guide future patient selection for this procedure. LVOT EOA is a ‘flow-independent’ metric which has the potential to aid in characterizing LVOT obstruction severity.
Associations of cognitive performance with cardiovascular magnetic resonance phenotypes in the UK Biobank
Authors: Raisi-Estabragh Zahra , M'Charrak Amine , McCracken Celeste , Biasiolli Luca , Ardissino Maddalena , Curtis Elizabeth M , Aung Nay , Suemoto Claudia K , Mackay Clare , Suri Sana , Nichols Thomas E , Harvey Nicholas C , Petersen Steffen E , Neubauer Stefan
Published: April 2021

Aims

Existing evidence suggests links between brain and cardiovascular health. We investigated associations between cognitive performance and cardiovascular magnetic resonance (CMR) phenotypes in the UK Biobank, considering a range of potential confounders.

Methods and results

We studied 29 763 participants with CMR and cognitive testing, specifically, fluid intelligence (FI, 13 verbal-numeric reasoning questions), and reaction time (RT, a timed pairs matching exercise); both were considered continuous variables for modelling. We included the following CMR metrics: left and right ventricular (LV and RV) volumes in end-diastole and end-systole, LV/RV ejection fractions, LV/RV stroke volumes, LV mass, and aortic distensibility. Multivariable linear regression models were used to estimate the association of each CMR measure with FI and RT, adjusting for age, sex, smoking, education, deprivation, diabetes, hypertension, high cholesterol, prior myocardial infarction, alcohol intake, and exercise level. We report standardized beta-coefficients, 95% confidence intervals, and P-values adjusted for multiple testing. In this predominantly healthy cohort (average age 63.0 ± 7.5 years), better cognitive performance (higher FI, lower RT) was associated with larger LV/RV volumes, higher LV/RV stroke volumes, greater LV mass, and greater aortic distensibility in fully adjusted models. There was some evidence of non-linearity in the relationship between FI and LV end-systolic volume, with reversal of the direction of association at very high volumes. Associations were consistent for men and women and in different ages.

Conclusion

Better cognitive performance is associated with CMR measures likely representing a healthier cardiovascular phenotype. These relationships remained significant after adjustment for a range of cardiometabolic, lifestyle, and demographic factors, suggesting possible involvement of alternative disease mechanisms.
Heart healthy cities: genetics loads the gun but the environment pulls the trigger
Authors: Münzel Thomas , Sørensen Mette , Lelieveld Jos , Hahad Omar , Al-Kindi Sadeer , Nieuwenhuijsen Mark , Giles-Corti Billie , Daiber Andreas , Rajagopalan Sanjay
Published: April 2021

The world’s population is estimated to reach 10 billion by 2050 and 75% of this population will live in cities. Two-third of the European population already live in urban areas and this proportion continues to grow. Between 60% and 80% of the global energy use is consumed by urban areas, with 70% of the greenhouse gas emissions produced within urban areas. The World Health Organization states that city planning is now recognized as a critical part of a comprehensive solution to tackle adverse health outcomes. In the present review, we address non-communicable diseases with a focus on cardiovascular disease and the urbanization process in relation to environmental risk exposures including noise, air pollution, temperature, and outdoor light. The present review reports why heat islands develop in urban areas, and how greening of cities can improve public health, and address climate concerns, sustainability, and liveability. In addition, we discuss urban planning, transport interventions, and novel technologies to assess external environmental exposures, e.g. using digital technologies, to promote heart healthy cities in the future. Lastly, we highlight new paradigms of integrative thinking such as the exposome and planetary health, challenging the one-exposure-one-health-outcome association and expand our understanding of the totality of human environmental exposures.
Cardiovascular risk stratification by coronary computed tomography angiography imaging: current state-of-the-art
Authors: Antonopoulos Alexios S , Angelopoulos Andreas , Tsioufis Konstantinos , Antoniades Charalambos , Tousoulis Dimitris
Published: April 2021

Current cardiovascular risk stratification by use of clinical risk score systems or plasma biomarkers is good but less than satisfactory in identifying patients at residual risk for coronary events. Recent clinical evidence puts now further emphasis on the role of coronary anatomy assessment by coronary computed tomography angiography (CCTA) for the management of patients with stable ischaemic heart disease. Available computed tomography (CT) technology allows the quantification of plaque burden, identification of high-risk plaques, or the functional assessment of coronary lesions for ischaemia detection and revascularization for refractory angina symptoms. The current CT armamentum is also further enhanced by perivascular Fat Attenuation Index (FAI), a non-invasive metric of coronary inflammation, which allows for the first time the direct quantification of the residual vascular inflammatory burden. Machine learning and radiomic features’ extraction and spectral CT for tissue characterization are also expected to maximize the diagnostic and prognostic yield of CCTA. The combination of anatomical, functional, and biological information on coronary circulation by CCTA offers a unique toolkit for the risk stratification of patients, and patient selection for targeted aggressive prevention strategies. We hereby provide a review of the current state-of-the art in the field and discuss how integrating the full capacities of CCTA into clinical care pathways opens new opportunities for the tailored management of coronary artery disease.
European Union Child Guarantee—challenges raised by the welcome promise of free healthcare for marginalized children
Authors: Rigby Michael J
Published: April 2021

Background

Children are dependent on the way in which society provides healthcare, with primary and preventive care being initial components. They also have a generally acclaimed right to health, and to lack of impediment to access to healthcare. In a major initiative, the European Parliament has proposed a Child Guarantee to include free access to healthcare for marginalized children, and a Feasibility Study has been completed with positive results. However, there has been little analysis of national policies toward free access to healthcare for children, including longer-term treatment, mental health or adolescent health services, or of charges and indirect financial barriers to access

Methods

Data on policies for children’s access to healthcare from two recent European Community wide studies were re-analyzed and matched. Primary care, immunization, surveillance screening, minor illness, a more significant medium-term condition, and reproductive health were included. Additionally, data from a European survey of children reported as having unmet medical needs were revisited. Composite summaries relating to all 28 EU countries as of 2019 were produced.

Results

Only three EU-28 countries provided totally free services, though 26 countries provide free primary and preventive services. There is evidence of some children having unmet medical needs in 21 countries, with Expense being the main quoted factor.

Conclusion

There is widespread variation across Europe in free access for children to healthcare, little comparative study of policies and their effects on enabling or hindering access, and minimal data collection. This compromises achievement of the Guarantee, and initiatives are needed.
Strongyloides RNA-seq Browser: a web-based software platform for on-demand bioinformatics analyses of Strongyloides species
Authors: Bryant Astra S , DeMarco Stephanie F , Hallem Elissa A
Published: April 2021

Soil-transmitted gastrointestinal parasitic nematodes infect approximately 1 billion people worldwide, predominantly in low-resource communities. Skin-penetrating gastrointestinal nematodes in the genus Strongyloides are emerging as model systems for mechanistic studies of soil-transmitted helminths due to the growing availability of functional genomics tools for these species. To facilitate future genomics studies of Strongyloides species, we have designed a web-based application, the Strongyloides RNA-seq Browser, that provides an open source, user-friendly portal for accessing and analyzing Strongyloides genomic expression data. Specifically, the Strongyloides RNA-seq Browser takes advantage of alignment-free read mapping tools and R-based transcriptomics tools to re-analyze publicly available RNA sequencing datasets from four Strongyloides species: Strongyloides stercoralis, Strongyloides ratti, Strongyloides papillosus, and Strongyloides venezuelensis. This application permits on-demand exploration and quantification of gene expression across life stages without requiring previous coding experience. Here, we describe this interactive application and demonstrate how it may be used by nematode researchers to conduct a standard set of bioinformatics queries.
Prediction of biological age and evaluation of genome-wide dynamic methylomic changes throughout human aging
Authors: Amiri Roudbar Mahmoud , Mousavi Seyedeh Fatemeh , Salek Ardestani Siavash , Lopes Fernando Brito , Momen Mehdi , Gianola Daniel , Khatib Hasan
Published: April 2021

The use of DNA methylation signatures to predict chronological age and aging rate is of interest in many fields, including disease prevention and treatment, forensics, and anti-aging medicine. Although a large number of methylation markers are significantly associated with age, most age-prediction methods use a few markers selected based on either previously published studies or datasets containing methylation information. Here, we implemented reproducing kernel Hilbert spaces (RKHS) regression and a ridge regression model in a Bayesian framework that utilized phenotypic and methylation profiles simultaneously to predict chronological age. We used over 450,000 CpG sites from the whole blood of a large cohort of 4409 human individuals with a range of 10–101 years of age. Models were fitted using adjusted and un-adjusted methylation measurements for cell heterogeneity. Un-adjusted methylation scores delivered a significantly higher prediction accuracy than adjusted methylation data, with a correlation between age and predicted age of 0.98 and a root mean square error (RMSE) of 3.54 years in un-adjusted data, and 0.90 (correlation) and 7.16 (RMSE) years in adjusted data. Reducing the number of predictors (CpG sites) through subset selection improved predictive power with a correlation of 0.98 and an RMSE of 2.98 years in the RKHS model. We found distinct global methylation patterns, with a significant increase in the proportion of methylated cytosines in CpG islands and a decreased proportion in other CpG types, including CpG shore, shelf, and open sea (P < 5e-06). Epigenetic drift seemed to be a widespread phenomenon as more than 97% of the age-associated methylation sites had heteroscedasticity. Apparent methylomic aging rate (AMAR) had a sex-specific pattern, with an increase in AMAR in females with age related to males.
Isolation, characterization and epistasis of fluoride-resistant mutants of Caenorhabditis elegans.
Authors: Katsura I , Kondo K , Amano T , Ishihara T , Kawakami M
Published: April 2021

We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.
The peculiar evolution of apolipoprotein(a) in human and rhesus macaque.
Authors: Pesole G , Gerardi A , di Jeso F , Saccone C
Published: April 2021

Apo(a) is a low density lipoprotein homologous to plasminogen and has been shown to be involved in coronary atherosclerosis. In the present paper we will try to analyze the interesting evolutionary pattern of Apo(a). The plasminogen gene contains 5 cysteine-rich sequences, called kringles, followed by a protease domain. Apo(a), probably arisen by duplication of an ancestral plasminogen gene, contains many tandemly repeated copies of a sequence domain similar to the fourth kringle of plasminogen, 37 in human and at least 10 in the partially sequenced gene of rhesus, and the protease domain. We have found that the upstream kringles of apo(a) undergo Molecular Drive-like processes that produce high intraspecies similarity, whereas the downstream kringles evolve in a molecular clock-like manner and show an high interspecies sequence similarity. The latter regions are obviously suitable for dating the duplication event by which Apo(a) arose from plasminogen, but only if they evolve at the same rate in the two genes. Thus, we propose a "Molecular Clock Test" for assessing whether the comparison of two paralogous genes (or gene regions) can give reliable information on the dating of their origin by duplication. Applying this test to the kringle-4 domain of apo(a) and plasminogen gene, we demonstrate that the separation between the two genes by duplication dates back at about 90 Mya immediately before the radiation of mammals.
Approaches to half-tetrad analysis in bacteria: recombination between repeated, inverse-order chromosomal sequences.
Authors: Segall A M , Roth J R
Published: April 2021

In standard bacterial recombination assays, a linear fragment of DNA is transferred to a recipient cell and, at most, a single selected recombinant type is recovered from each merozygote. This contrasts with fungal systems, for which tetrads allow recovery of all meiotic products, including both ultimate recombinant products of an apparent single act of recombination. We have developed a bacterial recombination system in which two recombining sequences are placed in inverse order at widely separated sites in the circular chromosome of Salmonella typhimurium. Recombination can reassort markers between these repeated sequences (double recombination and apparent gene conversion), or can exchange flanking sequences, leading to inversion of the chromosome segment between the recombining sequences. Since two recombinant products remain in the chromosome of a recombinant with an inversion, one can, in principle, approach the capability of tetrad analysis. Using this system, the following observations have been made. (a) When long sequences (40 kb) recombine, conversion frequently accompanies exchange of flanking sequences. (b) When short sequences (5 kb) recombine, conversion rarely accompanies exchange of flanks. (c) Both recA and recB mutations eliminate inversion formation. (d) The frequency of exchanges between short repeats is more sensitive to the distance separating the recombining sequences in the chromosome. The results are presented with the assumption that inversions occur by simple interaction of two sequences in the same circular chromosome. In an appendix we discuss mechanistically more complex possibilities, some of which could also apply to standard fungal systems.
Genetic analysis of 63 mutations affecting maize kernel development isolated from Mutator stocks.
Authors: Scanlon M J , Stinard P S , James M G , Myers A M , Robertson D S
Published: April 2021

Sixty-three mutations affecting development of the maize kernel were isolated from active Robertson's Mutator (Mu) stocks. At least 14 previously undescribed maize gene loci were defined by mutations in this collection. Genetic mapping located 53 of these defective kernel (dek) mutations to particular chromosome arms, and more precise map determinations were made for 21 of the mutations. Genetic analyses identified 20 instances of allelism between one of the novel mutations and a previously described dek mutation, or between new dek mutations identified in this study; phenotypic variability was observed in three of the allelic series. Viability testing of homozygous mutant kernels identified numerous dek mutations with various pleiotropic effects on seedling and plant development. The mutations described here presumably arose by insertion of a Mu transposon within a dek gene; thus, many of the affected loci are expected to be accessible to molecular cloning via transposon-tagging.
Using allele frequencies and geographic subdivision to reconstruct gene trees within a species: molecular variance parsimony.
Authors: Excoffier L , Smouse P E
Published: April 2021

We formalize the use of allele frequency and geographic information for the construction of gene trees at the intraspecific level and extend the concept of evolutionary parsimony to molecular variance parsimony. The central principle is to consider a particular gene tree as a variable to be optimized in the estimation of a given population statistic. We propose three population statistics that are related to variance components and that are explicit functions of phylogenetic information. The methodology is applied in the context of minimum spanning trees (MSTs) and human mitochondrial DNA restriction data, but could be extended to accommodate other tree-making procedures, as well as other data types. We pursue optimal trees by heuristic optimization over a search space of more than 1.29 billion MSTs. This very large number of equally parsimonious trees underlines the lack of resolution of conventional parsimony procedures. This lack of resolution is highlighted by the observation that equally parsimonious trees yield very different estimates of population genetic diversity and genetic structure, as shown by null distributions of the population statistics, obtained by evaluation of 10,000 random MSTs. We propose a non-parametric test for the similarity between any two trees, based on the distribution of a weighted coevolutionary correlation. The ability to test for tree relatedness leads to the definition of a class of solutions instead of a single solution. Members of the class share virtually all of the critical internal structure of the tree but differ in the placement of singleton branch tips.