bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison between Exhaust Gas and Electrical Grid Heating of a Diffusion Absorption Refrigerator
Authors: Hussein Maral M , Hamada Khalaf I , Ahmed Omer K
Published: March 2021

A considerable quantity of waste energy in the exhaust system could be reutilized and added in a vehicle to run auxiliary systems, and contribute to improving the overall efficiency of the system. In the current work, a comparison between the conventional electrical grid and exhaust gas heating of an absorption refrigeration system was performed experimentally. A heat exchanger was fabricated to recover the wasted exhaust gas energy of internal combustion engine and operate the generator portion of a diffusion type refrigeration absorption system. The components performance of the absorption refrigerator was analyzed and estimated thermodynamically as a function of type energy source. The results revealed that the components temperatures were rapidly responded in case of the exhaust gas energy with the maximum and minimum steady state temperatures of the generator and evaporator of 140 °C and -1.1 °C, respectively. The steady state values of the COP can be reached from electrical grid, and the exhaust gas energy sources of the refrigerated system were 0.083 and 0.072, respectively. The key conclusion to be drawn is that the proposed system can be used to recycle the waste heat for refrigeration purpose; yet, with low COP values.
Controlling and Monitoring a Robot-Car Based on Smart Phone Applications
Authors: Meteab Wisam Kareem , ALRikabi Haider Th Salim , Al Sultani Salwan Ali Habeeb , Aljazaery Ibtisam A
Published: March 2021

A robot-car is typically an electro-mechanical system driven by electronic programming and computer programming. It can be managed by an Android smartphone APP. The remote buttons in the android app have been created in this paper by monitoring the motion of the car with them, using Bluetooth communication for the controller and android interfaces. The controller can be attached via UART to the Bluetooth module. The robot motion can be controlled according to commands obtained from Android. A robot in a car controlled by Android smartphones using Bluetooth waves will be presented. A video camera will send a video signal to the iPhone or Android device via Wi-Fi without the internet. The implementation will be shown and discussed clearly. The purposes of using this aspect are many and different such as tracking theft cars or exploring areas where humans cannot reach because of danger, pollution, or infested places. The consistent output of a robotic system along with quality and repeatability are unmatched.
Investigating Study of New Enhanced Parabolic Solar Collector Trough
Authors: Hameed Vinous M
Published: March 2021

Parabolic solar collector (PSC) was one of the most public used methods for heating purposes. This study modified PSC and increase its efficiency with minimum cost and space. A passive enhancement on PSC by adding fins on the outside tube surface was done. A copper tape was molded with a triangular fin shape around the copper receiver tube to increase the receiver tube’s heat-absorbing surface area. This enhancement increases the PSC thermal performance. The solar parabola collector has a length of 1 m while its width was 0.2m. The tube receiver has a 1m length with inside and outside diameters of 2.46cm and 2.54cm, respectively. Each fin has a 1 cm base and 1 cm height. The total number of triangular fins around the receiver tube was 100, which significantly enhanced PSC’s thermal performance. The readings were collected for fifteen days, with ten hours of continuous PSC automatic operation. The new SPC thermal performance was a promising technique with a low cost and efficient process compared to the traditional one with the same dimensions. The effect of volumetric flow rates was also studied where their values for 3, 5, 7, and 9 l/min. are 87.12%, 81.78%, 75.72%, and 58.53%, respectively.
An Experimental Study on New Multistage Solar Parabolic Trough Collector
Authors: Hameed Vinous M , Ibrahim Maryam
Published: March 2021

Solar parabolic collector is a clean a promising traditional technique due to the deficiency in energy resources. A new designed multistage solar parabolic trough collector was proposed and its thermal performance was investigated in this study. The collector width and length are 1m with a copper receiver tube outside and inside diameters of 2.54cm, 2.46cm, respectively. Four buses tube receiver were proposed inside the parabolic collector fitted in a thermocouple at the entrance and exit regions of each bus. A solar tracker with a solar sensor for maximum collecting incident sun rays from the sun rise to sun set. The test section is covered with a glass sheet for easy cleaning and to protect the system from losing heat to the surrounding. To evaluate the thermal performance of the new collector, several variables were studied which are: temperature difference between the fluid inlet and outlet regions, heat absorbed by the collector, convective heat transfer rate, and collector thermal efficiency. All the studied variables show that minimum water volumetric flow rates will give max temperature difference between the fluid inlet and outlet regions, heat absorbed by the collector, convective heat transfer rate, and collector thermal efficiency respectively.
Modeling and Analysis of a Novel Smart Knee Joint Prosthesis for Transfemoral Amputation
Authors: Kamel SH H , Hamzah M N , Atiyah Q A , Abdulateef S A
Published: March 2021

The absence of a limb impacts devastatingly on any person, especially if it is the lower limb as it is paramount to human locomotion. The effect of mobility loss reduces independence, and affects amputees’ lifestyles. A smart prosthetic knee joint is designed and manufactured in which the amputee above the knee can perform various daily and effective movements. It is distinguished by its distinctive and very high efficiency mechanically and electronically. The new design of the artificial smart knee joint has proven to be 100% successful as a passive mechanical movement. Should a power failure occur at the source, the ability to move smoothly is very high, proved highly efficient by walking, sitting, and applying various daily movement activities. The artificial knee joint is able to detect the movement of the residual limb according to the results of the movement study, thus allowing the prosthesis to simulate the biomechanics of the missing limb without any difficulty by using the finite element method (FEM) as a numerical technique. The results showed that 94.303 MPa and 0.1379 mm are the highest stresses and displacements experienced by the knee joints, respectively at 110°. This remains below the yield stresses of 339.15 MPa (depending on the properties of aluminum alloy material 2024-T3). On the other hand, the highest safety of factors was at 0° with a value of 5.5905 and the lowest safety of factors was at 110° with a value of 3.5964. The above results show that von Mises stresses and displacement increase with increasing the angle of flexion of the knee joint while the safety of factors decreases as the angle of flexion of the knee joint increases. The result of finite element analysis shows that the concept is safe enough to use for this specific topic.
Numerical Study on the Effect of Geometrical Parameter on the Thermal-Hydraulic Performance of the Metal Foam Heat Exchanger
Authors: Jasim Noor M , Fayyadh Ekhlas M , Hasan Moayed Razoki
Published: March 2021

A numerical study was conducted to examine the heat transfer and pressure drop of the metal foam-wrapped array heat exchanger. Effects of geometrical parameters, including arrangement of metal foam heat exchanger (two arrangement: fully-filled of metal foam while other have a gap between metal foam and the chamber walls), porosity, and the pore density on the thermal hydraulic performance of copper metal foam heat exchanger are examined. Numerical modelling was done considering the thermal non-equilibrium energy model and the Darcy-Forchheimer flow model for metal foam heat exchangers in the Star-CCM+ program version 2019. Four types of metal foams at fixed dimensional thickness of 0.91 with variable properties were adopted, where the pores density was 5PPI & 20PPI and the porosity was 89% and 95%. The heat exchanger system is simulated over a range of Reynolds number, based on tube diameter, from 1333 to 6555 with tubes heated at a constant wall temperature. The layout and geometry of the foam heat exchangers were compared with bare tube heat exchanger. It was found that At low porosity 89%, the configuration of metal foam heat exchanger that have pores density of 5PPI gives higher thermal performance (higher area goodness factor ratio) than 20 PPI. Also, decreasing porosity from 95% to 89% enhancement in the thermal performance was achieved. However, the metal foam heat exchanger that has a gap between metal foam and the chamber walls gave better thermal performance as compared with fully-filled foam heat exchanger.
Prediction of Indoor Airflow and Contaminant Transport in Office with Coupled Displacement Ventilation and Ceiling Radiant Cooling Panel
Authors: Shoky Mays Ahyab , Lafta Ali , Hussein Hasanen M
Published: March 2021

In this research, an experimental and numerical analysis have been conducted to predict the temperature, velocity distribution, and contaminant concentration in indoor spaces conditioned with corrugated ceiling radiant cooling panel (RCP) and Displacement Ventilation. The experiments were done on a model room with dimensions of (1.6m×1.2m×0.8m) built according to a suitable scale factor (1/5) to simulate the temperature, velocity distribution, and CO2 concentration by 36 measuring devices in an array scheme in three different zones and heights. Two cases were considered in this work, the first was with chilled ceiling panels only (without ventilation) and the second was with displacement ventilation. The experiments primary variable was the mean panel temperature (Tmp) with values of (15, 16, and 17oC). The second experimental cases were taken with an air inlet temperature of 24oC and a velocity of 0.7m/s with a range of outdoor air temperatures of (36 to 42oC). A computational fluid dynamics (CFD) program was built up to simulate air distribution in an enclosed environment with the DV-PCB system, which was then validated by the measured data. The validated CFD model was employed to analyze thermal comfort and indoor air quality in the enclosed environment with the DV-PCB coupled system using four indices: vertical temperature gradient, draft rate, normalized contaminant concentration, and age of air. The results indicate that CRCP is quite effective in reducing the temperature gradient created by DV. The results show that there is an enhancement in the total cooling capacity. Most of the computed results were presented as temperature contours and velocity vectors diagrams compared with the experimental work. The comparisons show a reasonably good agreement. Both experimental and numerical studies assist RCP for cooling purposes in the Iraqi climate for its ease, simplicity, and good comfort performance.
Mechanical Properties of Acrylic Laminations Resin (PMMA) Reinforced by Natural Nanoparticles and Hemp Fibers
Authors: Ahmed S H , Salih W M
Published: March 2021

The current research uses the chopped hemp fibers (HF) with a length of 0.5mm at a various mass fraction (0.0, 0.3, 0.6, and 0.9 wt%) to acrylic resin (PMMA) reinforced with 0.3% of walnut shell nanoparticles (WSP) for building up the properties of PMMA to be utilized in attachment prosthetics. Some mechanical and physical properties were studied. The results indicated that all properties were improved when the hemp fibers reached the most extreme value at 0.9% mass fraction of HF to polymer nanocomposite (PMMA: 0.3% walnut shell nanoparticle (WSP)) test. Therefore, this hybrid composite might be used for accomplishing the required properties for the prosthetic application.
Influence of Adding Nano Coating Layers on the Hardness and Impact strength Properties for Low Carbon Steel
Authors: Kareem Layth Zbbal Abd UL , Alithari Ali Sadiq , AL-Zurfi Nabeel
Published: March 2021

Nanotechnology is one of the great techniques that helping to considerably improve many technologies and industry sectors such as information technology, homeland security, medicine, transportation, energy, food safety, and environmental science. Low carbon steel is widely used in many applications because it is cheap and it has high workability. However, low surface hardness and impact toughness are its main disadvantages. In this work, the nanocoating of tungsten carbide (WC) has been added to the low carbon steel surface with a thickness of 30, 40, and 50μm by using the thermal spray process with the HVOF technique. The present work aims to investigate the coating layer influence on the hardness and impact toughness. The results showed a significant improvement in the hardness, reaching 94.7%, while the impact toughness improved by 36% for a sample coated with a 50μm comparing with uncoated samples. The improvement in the hardness and impact toughness is due to the good adhesion of nano coat with the steel surface and the high hardness of tungsten Carbide as well as the good toughness of tungsten. The thickness of the coating layer is detected by using the scanning electron microscope images for each spray time. The results show that the coating with a layer of a thickness of more than 50μm will cause flaking and removing the coating layers.
Graphene-Reinforced the Structure and Mechanical Properties of New PMMA-PVA Hybrid Nanocomposites
Authors: Abdullah Salah Shadhan , kadhim Mohammed Abdul , Al-Bermany Ehssan
Published: March 2021

Graphene challenges the logic with its behavior and properties because of its multiple uses, so scientists and researchers paid great attention to it. In this study, newly fabricated nanocomposites consist of polymethyl methacrylate and polyvinyl alcohol using Dimethylformamide-co-distilled water and Dimethylformamide solvent with various loading ratios (0.09, 0.18, and 0.27 wt.%) of graphene oxide nanosheets, applying a developed solution casting method. The microstructure, some physical and mechanical properties of the polymethyl methacrylate - polyvinyl alcohol/graphene oxide nanocomposites, such as density, viscosity, ultrasonic velocity, coefficient of ultrasonic absorption, compressibility and bulk modulus, etc. were measured. The method exhibited the successful synthesis of these nanocomposites for the first time with good homogeneity and good desperation as existing clearly in the images of the optical microscopy. Additionally, strong interfacial interaction was formed between the polymers and nano-graphene sheets as exhibited in Fourier-transform infrared spectra with the most functional group of polymer and graphene oxide in the nanocomposites. The scanning electron microscope images also confirmed this finding. These images illustrated the smooth and homogeneous fracture surface with good dispersion of the nanosheets of graphene oxide into the polymer mixture. The low loading ratio of graphene oxide in the matrix from 0.09 to 0.27 wt.% exhibited significant improvement of the viscosity of ultrasonic velocity, bulk modulus, and coefficient of absorption of the mechanical waves up to 79%, 63 %, 225%, and 127%, respectively, with the blended polymers. These findings could help to realize these new nanocomposites as promising materials for wide applications, such as car glass and backlight and ultraviolet filters applications.
Optimization of Manufacturing Titanium-Magnesium alloy for Biomaterial Applications using Grey Relational Analyses
Authors: Al-Ethari Haydar , Abbas Sundus , Zamel Ekhlas Khalid
Published: March 2021

The present paper is focusing on improving the performance of titanium-magnesium alloys prepared by the powder metallurgy technique. These alloys show good biocompatibility and bioactivity, but there is still a demand to study their manufacturing factors. Optimizing the manufacturing process of Ti-Mg alloys increases its expected life. The response selected to evaluate the produced alloys are the hardness, the compressive strength, and the porosity, while the affecting manufacturing parameters are the compacting pressure, sintering time, and magnesium content. Three levels of these parameters were selected to design the experiments based on a standard L9 orthogonal array of the Taguchi method. A Grey relational analysis method was performed to optimize the responses. The obtained experimental results were analyzed using Minitab 16 software at a confidence level of 0.5%. The results indicated that the selected parameters significantly influence the responses of the alloy samples. The optimum level of the affecting parameters was found in a compacting pressure of 760MPa, sintering time of 6hours, and 15wt% of magnesium content.
Fabrication and Study Properties of ZnO/SiC Quantum Dots
Authors: Al-Ali Entesar SJ , Abdalwahid KR , Al-Sultani Kadhim F
Published: March 2021

In this research, heterojunction was developed by using SiC quantum dots. High-quality n-ZnO film on commercial p-SiC quantum dots has been prepared based on utilizing pulse laser deposition technique and spin coating under the pressure of 10−5 mbar, deposited at room temperature on a substrate of glass at various values of the thickness (113.3 and 160) nm, respectively. Then, annealed for two hours at 450 °C. ZnO/SiC QDs were described by the estimation of XRD and FE-SEM. XRD estimation uncovered that the SiC QDs prepared by spin coating with dye were hexagonal structure. The pulse laser deposition PLD method used to make ready ZnO thin film was hexagonal wurtzite with high-quality polycrystalline. UV-Visible spectrophotometer utilized in the range of (200-800) nm to determine spectral absorbance, transmittance, and energy gap of heterojunction. The optical properties results showed that the transmittance was (98 and 87)% for ZnO film and SiC, respectively. The pure ZnO thin film allowed a direct energy gap (Eg) that was 3.8 eV, while SiC QDs were 2.65 eV direct energy gap.
Investigation of the Polyol Types and Isocyanate Concentrations on the Rheological, Morphological and Mechanical Properties of Polyurethane Foams
Authors: Mohamed Dhey Jawad , Hadi Nizar Jawad , Alobad Zoalfokkar Kareem
Published: March 2021

This research studies the preparation and characterization of polyurethane foams, which are produced from the reaction of isocyanate Methylene Diphenyl Diisocyante “MDI” and polyol with water being used as a chemical blowing agent. The effect of isocyanate concentration on the cross-linking formation of polyurethane samples and its influence on the final properties of the foams were investigated. Each type of polyols (Local commercial market polyester, Quickmast120 and Quickmast110 polyether) were mixed with the isocyanate at equivalent ratio of (isocyanate: polyol) (0.5:1, 1:1, 2:1 and 3:1) to prepare polyurethane foam using one shot method. Rheological tests were performed for the polyols and isocyanate to find out their effect on the formability processes. The morphology and structure were performed using FTIR and digital microscopy. The tensile strength, compression strength and the hardness were conducted to show the effect of isocyanate concentrations on the mechanical properties of samples. The result display the Quickmast 120 polyol was unsuitable due to the large cells, unstable rheological properties and high hardness, which leads to a loss of flexibility of the polyurethane foams. The ratio of (1:1) (polyol/isocyanate) was the best in terms of the formability of the foam giving the smaller cells size and the best mechanical characteristics as compared to other concentrations of isocyanate.
Effects of Titanium Dioxide Nanoparticles on the Mechanical Strength of Epoxy Hybrid Composite Materials Reinforced with Unidirectional Carbon and Glass Fibers.
Authors: Abass Basim A , Hunain Mustafa B , Khudair Jaafar M A
Published: March 2021

The present work describes the development of hybrid epoxy composite reinforced with unidirectional carbon, glass fibers and nano-TiO2 powder in order to study some of its mechanical properties. Titanium dioxide (TiO2) were dispersed in epoxy with different weight fractions (1, 3, and 5 wt. %) using sonication. Composite materials under study have been prepared by reinforcing the resulted nanocomposite by three different layers of unidirectional carbon fibers and glass bidirectional fibers using hand lay-up technique. Tensile and hardness tests as well as the surface roughness test have been performed during the experimental work. It has been observed that the tensile strengths of the fiber-reinforced polymer composites increase with fiber content, and TiO2 nanoparticles up to a maximum value of 3 wt % after which it decreases. The value, modulus of elasticity, tension resistance, and hardness of the fiber-reinforced polymer composites increase with increasing fiber loading. The results obtained in this work show that the addition of TiO2 nanoparticles at up to 3%wt to the epoxy composite reinforced with unidirectional carbon and glass fibers enhances the mechanical strength of such material.
Laser Treatment Influence on Estimated Fatigue Life of AA2017
Authors: Al-Helli Ali H , Hamza Assad Kh
Published: March 2021

This paper deals with improving the fatigue strength of AA2017-T0 aluminium alloy by using laser surface treatment. A set of rotating fatigue specimens were machined and prepared for this rezone. Half number of them was surface-treated using 1 Joule laser machine. The fatigue tests for the treater and as reserved specimens were used for different loads to draw the S-N curves. It was shown that the laser treatment was improving the fatigue strength for the alloy. The effect of varying the stress amplitude through-loading life was studied. It was shown that the (high-low) loading types give a longer life than the (low-high) loading types. The results show that the thermal laser treatment of the surface of the aluminium alloy AA2017 gives higher hardness and generates compression residual stresses that improving the mechanical properties of the alloy. Comparing experimental and numerical finite element results gives a good agreement with maximum error not exceeding (9.68%).
Effect of Different Multi-Walled Carbon Nanotubes MWCNTs on Mechanical and Physical Properties of Epoxy Nanocomposites
Authors: Mahmood Olfat A , Jameel Zainab N , Abdullah Hind W
Published: March 2021

Different types of long and short multiwalled carbon nanotubes (MWCNTs) were used as structural support in epoxy resin with a percentage of weight (0.1,0.2,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,4.5,&5) wt. percent, Utilization of direct mixing processes to prepare Nano-Composites (Epoxy/MWCNTs). The ultrasonic mixing method has been used to disperse the nanotubes into the epoxy resin system. SEM was used to demonstrate the dispersion in the epoxy polymer matrix of different MWCNT concentrations. The findings show that electrical conductivity properties boost effect, thermal conductivity coefficient, and A.C with percentage enhancement of less than 2 percent, and then raising with further raise in the content of MWCNTs.
Design and Construction of Device for Rubber Material Fatigue Test
Authors: Al-Raheem Saddam K , Jweeg Muhsin J , Hassan Abdul kareem F
Published: March 2021

Due to the wide use of rubber components in different engineering applications such as vibration isolators, engine mounts, car tires, and bridge bearing pads, etc., this rubber component is mostly subjected to repeated loads continuously. As a result, these loads will initiate cracks on the outside surface of a component and then, these cracks will grow over time, and then, the growth of the cracks increase leading to a failure of the rubber component. Many researchers have studied the behavior of fatigue under the action of many factors by utilizing many devices. These devices produce repeated loading on the sample made of rubber material, initiating cracks and, then crack growth, which leads to failure. Therefore, in this paper, a modern test device has been developed and constructed to perform laboratory rubber fatigue testing. This device has been proven to be accurate and with the ability of repeatability.
Synthesis and Characterization of Low-Cost Adsorbent and used for Alizarin Yellow GG and Alizarin Red S Dyes Removal from Aqueous Solutions
Authors: Al-Salihi K J , Alfatlawi W R
Published: March 2021

The effective use of a synthetic clay as ionic solid adsorbent for the removal of alizarin yellow GG and alizarin red S from aqueous solutions was investigated as low-cost adsorbent. Anionic clay of layered double hydroxide (LDH) was prepared from the salts of magnesium-aluminium nitrate in a ratio of (5:1) by co-precipitation method, characterized by X-ray diffraction (XRD), FT-IR spectroscopy and thermogravimetric analysis (TGA) to confirm the presence of LDH. The effect of various experimental parameters like contact time, initial and concentrations were investigated. The experiments were carried out in a batch system to optimize operation variables. The Langmuir and Freundlich isotherm equations applied to the data and the isotherm analysis indicated that the equilibrium was fitted to both of Freundlich and Langmuir. The models showed physio – chemical sorption for both of Alizarine yellow GG and Alizarin Red S on LDH surface. Kinetics study was made using lagergreen equations and the results show that the sorption of Alizarine Yellow GG and Red dye uptake on layered double hydroxide (LDH) were fitted with both pseudo-first order until the adsorption reach equilibrium, then, they fellow pseudo second order where the adsorption rates depend on the amount of adsorbent and concentration of adsorbate. The partition coefficient Kd for the sorption of alizarine yellow GG and alizarin red S on LDH were also determined and it was indicated that the value of Kd increases with time until equilibrium is reached and becomes constant because of the extra unoccupied sites until the adsorption reaches equilibrium.
Assembly of large hBN nanocrystal arrays for quantum light emission
Authors: Preuß Johann A , Rudi Eduard , Kern Johannes , Schmidt Robert , Bratschitsch Rudolf , Michaelis de Vasconcellos Steffen
Published: March 2021

We fabricate rectangular arrays of hexagonal boron nitride (hBN) nanoplatelet clusters extending over hundreds of microns. Positioning is achieved by capillary assembly of suspended hBN particles into submicron polymer holes, patterned by electron-beam lithography. After removal of the patterned polymer from the SiO2/Si surface, average positioning yields of 74% at the desired locations are routinely achieved. At 10% of the locations, single-photon emitters (SPEs) are found. Thermal post-annealing of the prepared samples at 850 °C increases the number of SPEs by 50%. Our work paves the way for the production of wafer-scale SPE arrays based on commercially available hBN nanocrystals for a systematic statistical analysis of individually addressable SPEs, as well as for deterministic coupling of many emitters to a large number of photonic structures on photonic chips.
TIGER: inferring DNA replication timing from whole-genome sequence data
Authors: Koren Amnon , Massey Dashiell J , Bracci Alexa N
Published: March 2021

Motivation

Genomic DNA replicates according to a reproducible spatiotemporal program, with some loci replicating early in S phase while others replicate late. Despite being a central cellular process, DNA replication timing studies have been limited in scale due to technical challenges.

Results

We present TIGER (Timing Inferred from Genome Replication), a computational approach for extracting DNA replication timing information from whole genome sequence data obtained from proliferating cell samples. The presence of replicating cells in a biological specimen leads to non-uniform representation of genomic DNA that depends on the timing of replication of different genomic loci. Replication dynamics can hence be observed in genome sequence data by analyzing DNA copy number along chromosomes while accounting for other sources of sequence coverage variation. TIGER is applicable to any species with a contiguous genome assembly and rivals the quality of experimental measurements of DNA replication timing. It provides a straightforward approach for measuring replication timing and can readily be applied at scale.

Availability and implementation

TIGER is available at https://github.com/TheKorenLab/TIGER.

Supplementary information

Supplementary data are available at Bioinformatics online.
The computational neurology of movement under active inference
Authors: Parr Thomas , Limanowski Jakub , Rawji Vishal , Friston Karl
Published: March 2021

We propose a computational neurology of movement based on the convergence of theoretical neurobiology and clinical neurology. A significant development in the former is the idea that we can frame brain function as a process of (active) inference, in which the nervous system makes predictions about its sensory data. These predictions depend upon an implicit predictive (generative) model used by the brain. This means neural dynamics can be framed as generating actions to ensure sensations are consistent with these predictions—and adjusting predictions when they are not. We illustrate the significance of this formulation for clinical neurology by simulating a clinical examination of the motor system using an upper limb coordination task. Specifically, we show how tendon reflexes emerge naturally under the right kind of generative model. Through simulated perturbations, pertaining to prior probabilities of this model’s variables, we illustrate the emergence of hyperreflexia and pendular reflexes, reminiscent of neurological lesions in the corticospinal tract and cerebellum. We then turn to the computational lesions causing hypokinesia and deficits of coordination. This in silico lesion-deficit analysis provides an opportunity to revisit classic neurological dichotomies (e.g. pyramidal versus extrapyramidal systems) from the perspective of modern approaches to theoretical neurobiology—and our understanding of the neurocomputational architecture of movement control based on first principles.
The latitude gradient for multiple sclerosis prevalence is established in the early life course
Authors: Sabel Clive E , Pearson John F , Mason Deborah F , Willoughby Ernest , Abernethy David A , Taylor Bruce V
Published: March 2021

The strongest epidemiological clue that the environment at the population level has a significant impact on the risk of developing multiple sclerosis is the well established, and in many instances, increasing latitudinal gradient of prevalence, incidence and mortality globally, with prevalence increasing by up to 10-fold between the equator and 60° north and south. The drivers of this gradient are thought to be environmental with latitude seen as a proxy for ultraviolet radiation and thus vitamin D production; however, other factors may also play a role. Several important questions remain unanswered, particularly when in the life course is the gradient established, does lifetime migration mitigate or exacerbate previously reported latitude gradients at location of diagnosis, and do factors such as sex or multiple sclerosis disease phenotype influence the timing or significance of the gradient? Utilizing lifetime residence calendars collected as part of the New Zealand National Multiple Sclerosis Prevalence Study, we constructed lifetime latitudinal gradients for multiple sclerosis from birth to prevalence day in 2006 taking into account migration internally and externally and then analysed by sex and multiple sclerosis clinical course phenotype. Of 2917 individuals living in New Zealand on prevalence day, 7 March 2006, with multiple sclerosis, 2127 completed the life course questionnaire and of these, 1587 were born in New Zealand. All cohorts and sub-cohorts were representative of the overall multiple sclerosis population in New Zealand on prevalence day. We found that the prevalence gradient was present at birth and was, in fact, stronger than at census day, and the slope of the gradient persisted until the age of 12 before gradually declining. We found that internal and external migration into New Zealand had little, if any, effect on the gradient except to decrease the significance of the gradient somewhat. Finally, we found as we had reported previously, that the lifetime prevalence gradients were largely driven by females with relapse onset multiple sclerosis. These findings confirm for the first time the importance of early life environmental exposures in the risk of multiple sclerosis indicating strongly that exposures as early as in utero and at birth drive the latitudinal gradient. Consequently, prevention studies should be focused on high-risk individuals and populations from the earliest possible time points especially, when appropriate, on females.
Human cardiosphere-derived stromal cells exposed to SARS-CoV-2 evolve into hyper-inflammatory/pro-fibrotic phenotype and produce infective viral particles depending on the levels of ACE2 receptor expression
Authors: Amendola Alessandra , Garoffolo Gloria , Songia Paola , Nardacci Roberta , Ferrari Silvia , Bernava Giacomo , Canzano Paola , Myasoedova Veronika , Colavita Francesca , Castilletti Concetta , Sberna Giuseppe , Capobianchi Maria Rosaria , Piacentini Mauro , Agrifoglio Marco , Colombo Gualtiero Ivanoe , Poggio Paolo , Pesce Maurizio
Published: March 2021

Aims

Patients with severe respiratory syndrome caused by SARS-CoV-2 undergo cardiac complications due to hyper-inflammatory conditions. Although the presence of the virus has been detected in the myocardium of infected patients, and infection of induced pluripotent cell-derived cardiomyocytes has been demonstrated, the reported expression of Angiotensin-Converting Enzyme-2 (ACE2) in cardiac stromal cells suggests that SARS-CoV-2 may determine cardiac injury by sustaining productive infection and increasing inflammation.

Methods and results 

We analysed expression of ACE2 receptor in primary human cardiac stromal cells derived from cardiospheres, using proteomics and transcriptomics before exposing them to SARS-CoV-2 in vitro. Using conventional and high sensitivity PCR methods, we measured virus release in the cellular supernatants and monitored the intracellular viral bioprocessing. We performed high-resolution imaging to show the sites of intracellular viral production and demonstrated the presence of viral particles in the cells with electron microscopy. We finally used RT–qPCR assays to detect genes linked to innate immunity and fibrotic pathways coherently regulated in cells after exposure to the virus.

Conclusions 

Our findings indicate that cardiac stromal cells are susceptible to SARS-CoV-2 infection and produce variable viral yields depending on the extent of cellular ACE2 receptor expression. Interestingly, these cells also evolved towards hyper-inflammatory/pro-fibrotic phenotypes independently of ACE2 levels. Thus, SARS-CoV-2 infection of myocardial stromal cells could be involved in cardiac injury and explain the high number of complications observed in severe cases of COVID-19.
European-wide policymaking at the urban level: a qualitative study
Authors: Mueller Julia , Patterson Lesley , Jakab Matyas , Higgerson James , Steels Stephanie , Verma Arpana
Published: March 2021

Background

Inter-urban area (UA) health inequalities can be as dramatic as those between high and low-income countries. Policies need to focus on the determinants of health specific to UAs to effect change. This study therefore aimed to determine the degree to which policymakers from different countries could make autonomous health and wellbeing policy decisions for their urban jurisdiction area.

Methods

We conducted a cross-sectional, qualitative interview study with policymakers recruited from eight European countries (N = 37).

Results

The reported autonomy among policymakers varied considerably between countries, from little or no autonomy and strict adherence to national directives (e.g. Slovak Republic) to a high degree of autonomy and ability to interpret national guidelines to local context (e.g. Norway). The main perceived barriers to implementation of local policies were political, and the importance of regular and effective communication with stakeholders, especially politicians, was emphasized. Having qualified health professionals in positions of influence within the UA was cited as a strong driver of the public health (PH) agenda at the UA level.

Conclusion

Local-level policy development and implementation depends strongly on the degree of autonomy and independence of policymakers, which in turn depends on the organization, structure and financial budget allocation of PH services. While high levels of centralization in small, relatively homogenous countries may enhance efficient use of resources, larger, more diverse countries may benefit from devolution to smaller geographical regions.
Gag p24 Is a Marker of Human Immunodeficiency Virus Expression in Tissues and Correlates With Immune Response
Authors: Wu Guoxin , Zuck Paul , Goh Shih Lin , Milush Jeffrey M , Vohra Poonam , Wong Joseph K , Somsouk Ma , Yukl Steven A , Shacklett Barbara L , Chomont Nicolas , Haase Ashley T , Hatano Hiroyu , Schacker Timothy W , Deeks Steven G , Hazuda Daria J , Hunt Peter W , Howell Bonnie J
Published: March 2021

We demonstrate that human immunodeficiency virus (HIV) gag p24 protein is more readily detected in gut and lymph node tissues than in blood CD4+ T cells and correlates better with CD4 count during antiretroviral therapy (ART). Gut p24 levels also measurably decline with ART in natural controllers. During ART, gut p24 expression is more strongly associated both with HIV-specific CD8+ T-cell frequency and plasma soluble CD14 levels than gut HIV RNA expression. This study supports using gag p24 as a marker of HIV expression in HIV+ tissues to study effects of viral persistence and to monitor efficacy of treatment in HIV-based clearance studies.
Recommendations for Influenza Vaccination in Burns Patients Based on a Systematic Review of the Evidence
Authors: Nweze Kirsty , Hart-Pinto Andrew , Philip Liby , Mortimer Kalani , Whitehead Kathryn A , Shokrollahi Kayvan
Published: March 2021

Severe burn injury is a serious systemic insult that can lead to life-threatening secondary infections. Immunosuppression, inhalation injury, and prolonged length of hospital stay are factors that predispose patients to severe respiratory tract infections. Furthermore, evidence shows that burns can put one at risk of infection long after the original injury. Currently in the United Kingdom, the annual National Flu Immunisation programme outlines guidance for groups who are deemed high risk and, therefore, eligible for the influenza vaccine. At present, no guidance exists for the administration of the influenza vaccine in burn-injured patients, despite knowledge of immunosuppression. The aim of this literature review is to examine the evidence for associations between burn injury and influenza and, where available, evaluate efficacy of influenza vaccines in this cohort. In addition, literature was searched for the effectiveness of the influenza vaccine in patients 65 years and above and in patients admitted to the intensive care unit (ICU), two domains common to patients with severe burns. Three papers were found to suggest increased susceptibility to influenza following burn injury; however, no papers studying the effectiveness of the influenza vaccine in this group were found. Several studies demonstrated improved outcomes in patients over 65 years and patients admitted to ICU. Following the evaluation of the evidence, this review advocates for the consideration of hospitalized burn patients for the influenza vaccine. We suggest the avoidance of vaccine administration in the acute burn phase. Further prospective clinical trials would be required to validate these findings.
Factors Associated With Mortality Following Burns Complicated by Necrotizing Skin and Soft Tissue Infections: A Systematic Review and Meta-Analysis of Individual Participant Data
Authors: Klifto Kevin M , Gurno Caresse F , Seal Stella M , Hultman C Scott
Published: March 2021

We reviewed studies with individual participant data of patients who sustained burn injury and subsequently developed necrotizing skin and soft tissue infections (NSTI). Characteristics and managements were compared between patients who lived and patients who died to determine factors associated with mortality. Six databases (PubMed, EMBASE, Cochrane Library, Web of Science, Scopus, and CINAHL) were searched. PRISMA-IPD guidelines were followed throughout the review. Eligible patients sustained a burn injury, treated in any setting, and diagnosed with a NSTI following burn injury. Comparisons were made between burned patients who lived “non-mortality” and burned patients who died “mortality” following NSTI using non-parametric univariate analyses. Fifty-eight studies with 78 patients were published from 1970 through 2019. Non-mortality resulted in 58 patients and mortality resulted in 20 patients. Patients with mortality had significantly greater median %TBSA burned (45%[IQR:44–64%] vs 35%[IQR:11–59%], P = .033), more intubations (79% vs 43%, P = .013), less debridements (83% vs 98%, P = .039), less skin excisions (83% vs 98%, P = .039), more complications (100% vs 50%, P < .001), management at a burn center (100% vs 71%, P = .008), underwent less flap surgeries (5% vs 35%, P = .014), less graft survival (25% vs 86%, P < .001), and less healed wounds (5% vs 95%, P < .001), compared to patients with non-mortality, respectively. Non-mortality patients had more debridements, skin excised, systemic antimicrobials, skin graft survival, flaps, improvement following surgery, and healed wounds compared to mortality patients. Mortality patients had greater %TBSA burned, intubations, management at a burn center and complications compared to non-mortality patients.
Association Between Sex and Immune-Related Adverse Events During Immune Checkpoint Inhibitor Therapy
Authors: Jing Ying , Zhang Yongchang , Wang Jing , Li Kunyan , Chen Xue , Heng Jianfu , Gao Qian , Ye Youqiong , Zhang Zhao , Liu Yaoming , Lou Yanyan , Lin Steven H , Diao Lixia , Liu Hong , Chen Xiang , Mills Gordon B , Han Leng
Published: March 2021

Background

Accumulated evidence supports the existence of sex-associated differences in immune systems. Understanding the role of sex in immune-related adverse events (irAEs) is important for management of irAE in patients receiving immunotherapy.

Methods

We performed meta-analysis on published clinical study data and multivariable logistic regression on pharmacovigilance data and applied a propensity algorithm to The Cancer Genome Atlas omics data. We further validated our observations in 2 independent in-house cohorts of 179 and 767 cancer patients treated with immune checkpoint inhibitors.

Results

A meta-analysis using 13 clinical studies that reported on 1096 female patients (36.8%, 95% confidence interval [CI] = 35.0% to 38.5%) and 1886 male patients (63.2%, 95% CI = 61.5% to 65.0%) demonstrated no statistically significant irAE risk difference between the sexes (odds ratio [OR] = 1.19, 95% CI = 0.91 to 1.54, 2-sided P = .21). Multivariable logistic regression analysis of 12 225 patients from the Food and drug administration Adverse Event Reporting System (FAERS) and 10 979 patients from VigiBase showed no statistically significant difference in irAEs by sex. A propensity score algorithm used on multi-omics data for 6019 patients from The Cancer Genome Atlas found no statistically significant difference by sex for irAE-related factors or pathways. The retrospective analysis of 2 in-house patient cohorts validated these results (OR = 1.55, 95% CI = 0.98 to 2.47, false discovery rate = 0.13, for cohort 1; OR = 1.16, 95% CI = 0.86 to 1.57, false discovery rate = 0.39, for cohort 2).

Conclusions

We observed minimal sex-associated differences in irAEs among cancer patients who received immune checkpoint inhibitor therapy. It may be unnecessary to consider sex effects for irAE management in clinical practice.
Border control and SARS-CoV-2: an opportunity for generating highly policy-relevant, real-world evidence
Authors: Burns Jacob , Movsisyan Ani , Rehfuess Eva A , Stratil Jan M
Published: March 2021

We propose a study type that would contribute to the evidence base related to border control measures. Over a study period during which arriving travellers are quarantined, repeated testing and/or screening at regular intervals would provide real-world data on the relative and combined effects of various screening and testing measures.
Multicolour photometry and Gaia EDR3 astrometry of two couples of binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324)
Authors: Bisht D , Zhu Qingfeng , Yadav R K S , Ganesh Shashikiran , Rangwal Geeta , Durgapal Alok , Sariya Devesh P , Jiang Ing-Guey
Published: March 2021

This paper presents a comprehensive analysis of two pairs of binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324) located in the fourth quadrant of our Galaxy. For this purpose, we use different data taken from VVV survey, WISE, VPHAS, APASS, and GLIMPSE along with Gaia EDR3 astrometric data. We identified 584, 429, 692, and 273 most probable cluster members with membership probability higher than $80 {{\ \rm per\ cent}}$ towards the region of the clusters NGC 5617, Trumpler 22, NGC 3293, and NGC 3324. We estimated the value of $R=\frac{A_{V}}{E(B-V)}$ as ∼3.1 for the clusters NGC 5617 and Trumpler 22, which indicates the normal extinction law. The values of $R\, \sim 3.8$ and ∼1.9 represent the abnormal extinction law towards the clusters NGC 3293 and NGC 3324. Our kinematical analysis shows that all these clusters have circular orbits. Ages are found to be 90 ± 10 and 12 ± 3 Myr for the cluster pairs (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324), respectively. The distances of 2.43 ± 0.08, 2.64 ± 0.07, 2.59 ± 0.1, and 2.80 ± 0.2 kpc estimated using parallax are consistent with the values calculated by using the distance modulus. We have also identified 18 and 44 young stellar object candidates present in NGC 5617 and Trumpler 22, respectively. Mass function slopes are found to be in fair agreement with the Salpeter’s value. The dynamical study of these objects shows a lack of faint stars in their inner regions, which leads to the mass-segregation effect. Our study indicates that NGC 5617 and Trumpler 22 are dynamically relaxed but the other pair of clusters are not. Orbital along with the physical parameters show that the clusters in both pairs are physically connected.
Formation of Al containing molecular complexes in the gas phase in dense molecular clouds: quantum study of the radiative association of Al++H2 and Al++D2
Authors: Jones (nee Burdakova) Daria , Nyman Gunnar , Stoecklin Thierry
Published: March 2021

Radiative association (RA) of Al+ with H2 is the first step in the formation of AlH in gas phase and is here investigated theoretically. We use recent potential energy and dipole moment surfaces and a quantum approach based on the driven equations formalism for performing the dynamics for both the Al+-H2 and Al+-D2 systems. The obtained RA rate coefficients are compared with previous evaluations based on transition state theory and found to be orders of magnitude larger. They are also compared to those obtained recently for the similar systems Na+-H2/D2. The possible role played by RA of Al+ with H2 in the gas phase chemistry of dense molecular clouds is discussed.