bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation of a Canadian Well With One Circumferential Row of Internal Vortex Generators
Authors: Kharoua Nabil , Semmari Hamza , Haroun Mehdi , Korichi Houssem , Islam Md
Published: September 2022

Canadian wells are used for heating and cooling in residential buildings, agriculture and industry. They rely on the quasi-stable underground temperature at a certain depth throughout the year. One way to enhance the performance of this type of heat exchangers, is to implement internal Vortex Generators (VGs). The VGs contribute in disrupting the thermal boundary layer, intensifying turbulence and increasing the heat transfer coefficient.

Series of numerical simulations, using ANSYS FLUENT, were conducted to mimic the variable seasonal operational conditions of Canadian Wells during the year. One circumferential row of parallelepiped Vortex Generators was implemented in a real U-shaped tube Canadian Well geometry. The yearly ground and underground temperatures were implemented as sinusoidal functions of time and depth. The VGs were placed immediately downstream of the first bend close to the inlet. The Reynolds number was in the range 14975–42785. The ambient conditions were considered for the city of Constantine (Algeria) at an altitude of 600m over the sea level.

The VGs yielded an improvement of up to 8% of the heat transfer coefficient for different Reynolds numbers. The bend, upstream of the VGs, and the wake, downstream of them, play a key role in affecting the heat transfer locally.
Numerical Investigation of a Rotating Double Compression Ramp Intake
Authors: Margha Lubna , Hamada Ahmed A. , Ahmed Othman , Eltaweel Ahmed
Published: September 2022

The intakes of air-breathing high-speed flying vehicles produce a large share of the thrust propulsion. Furthermore, the propulsion performance of these engines increases when the single ramp intake is replaced with a multiple-ramps intake. Many scholars numerically and experimentally studied the high-speed engine performance over static single and multiple compression ramps. However, the transient behavior of the flow during the rotation of the double compression ramp from a single ramp is not fully investigated. The present paper aims to numerically investigate the transient shock reflection phenomenon over a rotating double wedge. The problem will start with a 3-Mach number inviscid flow over a single wedge. Then, a portion of the wedge will be rotated upstream at a quite low trailing Mach number to avoid the significant lag effect in the shock waves system. This idea could be applied in the supersonic intake or extensionally in the hypersonic intake of scramjets with a somehow complex mechanism. Further, the length of the rotating portion of the wedge will be changed three times to study its effect on the shock system. The results show a high gain in the pressure due to the rotation of the wedge. Moreover, the wave angles were larger at the low chord ratio value of w2/wi = 0.25 than at the high values of w2/wi at the same second wedge rotating angle, θ2, resulting in a higher pressure distribution.
Aerodynamic Analysis of the Utility Truck With the Morphing Boom Equipment
Authors: Patel Parth Y. , Jannoi Thannathorn , Zou Wenhui , Vantsevich Vladimir , Koomullil Roy
Published: September 2022

Global climate change has affected the human race for decades. As a result, severe weather changes and more substantial hurricane impact have become a typical scenario. Utility trucks with the morphing boom equipment are the first responders to access these disaster areas in bad weather conditions and restore the damages caused by the disaster. The stability of the utility trucks while driving in a heavy wind scenario is an essential aspect for the safety of the rescue crew, and aerodynamic forces caused by the wind flow constitute a significant factor that influences the stability of the utility truck. In this paper, the aerodynamic performance of the utility truck is modeled using the incompressible unsteady Reynolds Averaged Navier Stokes (URANS) model. The Ahmed body, a well-recognized benchmark test case used by the computational fluid dynamics (CFD) community for the aerodynamic model validation of automobiles, is used to validate this aerodynamic model. The validated aerodynamic model investigates the impact of heavy wind on the utility truck with the morphing boom equipment. The visualization of the flow field around the utility truck with the force and moment coefficients at various side slip angles are presented in this paper.
Joining of Metal-Thermoplastic-Tube-Joints by Hydraulic Expansion
Authors: Weber Florian , Lehmenkühler Peter , Hahn Marlon , Tekkaya A. Erman
Published: September 2022

To encounter current issues regarding climate change, the hybridization of structures with lighter, often dissimilar, materials is an essential cornerstone of lightweight design. The different mechanical behavior of these materials results in challenges in terms of joining. This paper utilizes the joining process by hydraulic expansion to manufacture tube-to-tube joints of aluminum alloy AA6060 T66 and thermoplastic polycarbonate (Lexan) at room temperature. In contrast to metals, elastic and plastic strains coexist in thermoplastics from the beginning of deformation. Based on the theory of linear elasticity, an equation was derived to calculate the fluid pressure that expands the polycarbonate up to a strain value where plastic strains start to increase significantly in comparison to elastic strains. Tensile tests of the joined tubes revealed that the transferable tensile load increased approximately exponentially with increasing plastic deformation of the polycarbonate. With ongoing plastic deformation, micro-cracks appeared and merged within the thermoplastic. The appearance of these so-called crazes had no negative influence on the transferable load within the range of applied fluid pressure.
One-Step 3D Printed Layers Along With xy-in Plane Directions for Enhanced Multifunctional Nanocomposites
Authors: Ravichandran Dharneedar , Song Kenan
Published: September 2022

Composite and hybrid materials displaying layered structures have broad applications in structural composites, fire retardant barriers, tissue scaffolds, and microelectronics. Inspired by biosystems, in this study, we explore the invention of a new 3D printing principle that can produce layered structures similar to those in trees, overcoming the bottleneck in additive manufacturing to include multi-materials. We use polyvinyl alcohol (PVA) and carbon nanotubes (CNTs) as material examples for producing alternating layers. With the unique 3D printing platform, Multiphase Direct Ink Writing (MDIW), the optimized dispersion quality and rheology behaviors allow the number of layers within an individual printing line to change between 4 and 512 layers. The mechanical tests consistently increased young’s modulus and ultimate tensile strength with decreased layer thickness and dispersion quality. The best-performed composites have 128 layers in one printing line, beyond which the dispersion of CNTs deteriorated due to aggregates. Due to the thin layer thickness, the improved composite mechanics relate to the closely packed CNTs and their alignment.

Moreover, we will also demonstrate this MDIW printing with different polymers (e.g., thermoplastic urethane and polylactic acid) and nanoparticles (e.g., iron oxide, carbon fibers) for mechanical enhancement and intelligent behaviors. This research demonstrated one new 3D printing method, MDIW, that can fabricate multilayered composites containing well-managed content in each layer. Our advanced manufacturing method is compatible with other materials and has potential use in batteries, supercapacitors, solar cells, regenerative medicine, and energetic systems requiring layered structures.
Characterization of Polylactic Acid Filament With Biodegradable Hemp Fiber Infused During Additive Manufacturing Process
Authors: Hanson Matthew , Yang Che-Hao
Published: September 2022

Fused Filament Fabrication (FFF) is one of the common methods among the Additive Manufacturing (AM) processes. In this study, hemp fiber, a sustainable, and fast degraded material introduced and mixed with fresh Polylactic Acid (PLA) filament with 3 wt%, 7.5 wt%, and 10 wt% to improve the drawbacks of pure PLA filament and sustain its required properties. The results from the fatigue testing of pure PLA, and various hemp-fiber infused PLA indicated that increasing the wt% content of a hemp fiber infused PLA specimen at a certain point does increase the ultimate bending stress as well as the overall fatigue life of a pure PLA specimen. The 10 wt% hemp fiber specimens provided a 7.32% increase in the mean ultimate flexural strength over pure PLA. The mean of Young’s modulus also increased by 10.65% for the 10 wt% hemp fiber specimen and by 23.05% for the 7.5 wt% hemp fiber specimen over PLA. The 10 wt% hemp fiber specimens also provided a 4.05% increase in fatigue life over PLA. The 3 wt% did not provide a significant improvement in the study. These findings provide insight into the AM processes and lead to the development of environment-friendly composites in the industries.
Micro-Architected Lattice-Based Mesh for Fiber Filters: A Novel Additive Manufacturing Architecture for Molded Fiber Tooling
Authors: Dominguez Jose , Gonzalez Paloma
Published: September 2022

Promising developments have shown the untapped potential of additive manufacturing (AM) for fabricating molded fiber molds (MFM), a critical piece for the molded fiber industry. This work builds upon AM implementations, presenting a novel application of micro-architected lattice structure to construct fiber filtering meshes attached to drainage channels, all combined in an “Integrated Mold.” Current AM approaches have failed to build low-cost and high lifespan tools. Instead, their design approach imitates the existing MFM structure, covering a base-shaped structure with a mesh. The main disadvantage of this method is the trade-off between water drainage and stiffness.

Lattice materials have shown the capability of building porous structures with high stiffness, strength-to-weight ratio, fatigue tolerance, and the capacity to control the flow of fluids. The methodology presented in this research defines a new approach for MFM design that provides a broader range of porosity and enhances water drainage capabilities without affecting structural performance. As a result, it retrieves enhanced control over the physical properties of MFM.

The studies presented in this paper show the functionality of lattice structures as filters for solid particles. Moreover, it offers an immediate application of this technology. The tools developed in this research have validated their capability to withstand more than a hundred cycles as tooling for MFP, proving their functionality for prototyping stages. This result seeks to accelerate the expansion of an industry that capitalizes on locally abundant, biodegradable, and recyclable raw materials.
Support Vector Machines for Classification of Direct Energy Deposition Standoff Distance for Improved Process Control
Authors: Alexander Zoe , DeVol Nathan , Emig Molly , Saleeby Kyle , Feldhausen Thomas , Kurfess Thomas , Fu Katherine , Saldana Christopher
Published: September 2022

A critical factor in the implementation of direct energy deposition is the ability to maintain the standoff distance between the nozzle and the build surface, as this influences powder capture efficiency and overall part quality. Due to process-related variations, layer height may vary, causing unintended variation in standoff distance and poor build quality. While prior work has utilized contact probing to qualify standoff distance during processing, in situ methods for qualification of standoff distance are of major interest. The present work seeks to understand efficacy of image-based methods for classifying standoff distance variation in real-time using support vector machines (SVMs). It was hypothesized that the size of the melt pool and the amount of spatter will have significant correlations with deviations in the standoff distance; thus, SVMs were used on a dataset that is comprised of morphological features of melt pool size and image entropy. The SVM model was used to classify melt pool images into categories according to standoff distance variation from nominal. K-folds cross validation was used to find the optimal hyperparameters for the SVM model. To understand the impact of the selected features on the classification performance and inference speed, multiple models were trained with differing numbers of included features. Results for classification score, inference time, and image preprocessing/feature extraction from these data are reported. The present results show that the SVM model was able to predict the standoff distance classification with an accuracy of 97 percent and a speed of 0.122 s per image, making it a viable solution for real-time control of standoff distance.
Mechanical Profile and 3D Printability of Cellular Structures
Authors: Rastegarzadeh Sina , Muthusamy Samuel , Huang Jida
Published: September 2022

Microstructures are critical elements for mechanical metamaterials design and fabrication. Tailoring the internal microscale structural pattern can achieve a much broader range of bulk properties than the constituent materials, thus enabling the metamaterial design with extraordinary properties. Studying the mechanical properties and fabricability of microstructures is critical for understanding metamaterials’ structural design and macroscale performances. This paper categorizes the commonly designed microstructures into two main classes: deterministic implicit function-based and stochastic nature-based designing strategies. The mechanical properties and 3D printability of typical instances within the two classes are studied and experimentally analyzed. Specifically, we investigate the macroscale mechanical properties (e.g., Young’s modulus, shear modulus, bulk modulus, percentage of anisotropy) of microstructures defined with triply periodic minimal surfaces (TPMS), Fourier series-based functions (FSFs), Gaussian random filed-based (GRF), and Voronoi-based microstructures. Asymptotic homogenization is exploited herein to study the macroscale properties of different microstructures, and the manufacturability of the structures is experimentally analyzed and validated on an FDM printer. We summarize the mechanical profiles and manufacturability of these microstructures defined by various principles. The resulting mechanical profiles and manufacturability of microstructures provide a reasonable basis for establishing a microstructure database and shed light on the on-demand structural units generation for metamaterial design and fabrication.
Roll to Roll Manufacturing and In-Line Imaging and Characterization of Functional Films
Authors: Glassmaker Nicholas , Mi Ye , Cakmak Mukerrem , Shakouri Ali
Published: September 2022

Roll-to-roll manufacturing is a promising platform to produce low cost, high quality electrical components and sensors for Internet of Things (IoT) applications. Within the roll-to-roll laboratories at Purdue University, a range of processes and machines have been developed to: 1) print patterns of conductive and sensing materials for use in electronic sensors, 2) cast films precisely with integrated functional materials, and 3) monitor quality of the printing and casting processes in-line in real time. A major development is the custom-designed and built Maxwell coating machine, which has enabled substantial quality improvements in slot-die coatings, as demonstrated by precise in-line thickness monitoring and imaging. As an illustrative example, we will show how we converted a design for a printed ion-selective electrode from a batch process to a roll-to-roll process. In-line process monitoring of coating thickness allowed us to identify high variability in the coating thickness due to an interaction between underlying printed electrodes and the drying process. By modifying the drying process, we demonstrated a substantial improvement as evidenced by the same in-line measurement technique. The overall process integrates several existing machines and processes in a novel way to create functional parts continuously, with data on individual parts gathered in real time.
Polymer Filament Extrusion Using LDPE Waste Polymer: Effect of Processing Temperature
Authors: Devra Rajdeep Singh , Srivastava Nishkarsh , Vadali Madhu , Arora Amit
Published: September 2022

Low-density polyethylene (LDPE) is a soft thermoplastic with extensive application as a packing material such as plastic bags, dispensing bottles, milk pouches, etc. Many LDPE bags are used and dumped in landfills every year, leading to millions of tons of persistent waste. In addition, the recycling of LDPE is of no commercial interest due to its low stiffness, poor mechanical properties, and limited commercial application. In the current work, we attempt to recycle milk pouches made of LDPE to create polymer filaments for fused deposition modeling (FDM), thereby adding value to waste plastic by converting it into high-value 3D printer filament. This research examines the feasibility of reclamation of waste LDPE milk pouches as filament for 3D printers and studies the changes in filament’s chemical and mechanical properties when produced at different temperatures. The waste milk pouches are cleaned thoroughly, shredded, and extruded using a single screw extruder at three nozzle temperatures, i.e., 150°C, 180°C, 210°C. The extruded specimens are analyzed using an optical microscope and scanning electron microscope (SEM) for surface texture. The effect of change in process temperature on flow behaviors is also studied by integrating a current sensor and an encoder. Fourier transform infrared spectroscopy (FTIR) analysis is performed on the filaments and the used LDPE milk pouches to compare the chemical bondings of the polymer. The mechanical properties of the extruded filaments are examined using dynamic mechanical analysis (DMA). The morphological analysis, chemical characterization, and mechanical characterization of prepared filaments are presented. The results show that the chemical bondings are intact after extrusion at all the temperatures examined in this work. The surface texture and the mechanical properties are better at higher temperatures owing to better fluidity and are more suitable for fused deposition modeling. Thus, it is possible to valorize waste LDPE milk pouches by transforming them into filaments for 3D printing.
Additive Manufacturing of Novel Beam Lattice Metamaterials With Hollow Cross-Sections Towards High Stiffness/Strength-to-Weight Ratio
Authors: Kobir Md Humaun , Liu Xin , Yang Yiran , Jiang Fang
Published: September 2022

Metamaterials have emerged as a group of promising materials with potential applications in a wide range of industries such as aerospace and automobile, owing to their unconventional properties. The state-of-the-art suggests that lattice metamaterials offer lightweight structures while ensuring good mechanical properties, and hollow lattices can be leveraged to achieve ultra-lightweight metamaterials to further broaden the application horizons. In this research, hollow cross-sections are designed for lattice-based metamaterials in order to achieve a high stiffness/strength-to-weight ratio. The Mechanics of Structure Genome method is adopted to perform the beam cross-section analysis, leading to three cross-sections studied including solid, elliptical, and rectangular cross-sections. The designed metamaterials with hollow cross-sections have complex structures and therefore they are fabricated using the Selective Laser Sintering process. The compressive tests suggest that metamaterials with hollow cross-sections have a higher stiffness-to-weight ratio of 25% to 30% in comparison with solid cross-sections. In addition, hollow lattice metamaterials demonstrate better energy absorption capability compared to solid lattices of the same density, which is a critical characteristic to avoid catastrophic mechanical failure. It is observed from the compressive tests that the nodes in the unit cells tend to break first, indicating possible future research to further enhance the strength of hollow lattice metamaterials.
Pre-Crosslinked Hybrid Hydrogels for 3D Bio-Printing Process: Rheological Analysis
Authors: Tuladhar Slesha , Nelson Cartwright , Habib Md Ahasan
Published: September 2022

Bioprinting for regenerative medicine has been gaining a lot of popularity in today’s world. Despite being one of the rigorously studied fields, there are still several challenges yet to be solved. Geometric fidelity and mechanical complexities stand as roadblocks when it comes to the printability of the customized scaffolds. Exploring the rheological properties of the compositions helps us understand the physical and mechanical properties of the biomaterials which are closely tied to the printability of the filament and eventually, geometric fidelity of the scaffolds. To ensure the structural integrity of the scaffolds, viscosity enhancers such as Carboxymethyl Cellulose (CMC) and crosslinkers like CaCl2 and CaSO4 were used. These crosslinkers can be used before (pre-crosslinking) and after (post-crosslinking) the extrusion of considered compositions to investigate and compare the outcome. To do this, mixtures of Carboxymethyl Cellulose (CMC, viscosity enhancer), Alginate, and CaCl2 and CaSO4 (crosslinkers) were prepared at various concentrations maintaining minimum solid content (≤ 8%). Each composition was subjected to a set of rheological tests like Flow curve for shear thinning behavior, three-point thixotropic for recovery rate, amplitude test for gelation point, and frequency tests. This research thoroughly investigates compositions when they are introduced to crosslinkers and viscosity enhancers which can be crucial for 3D printing world.
Robot Trajectory Generation for Multi-Axis Wire Arc Additive Manufacturing
Authors: Bhatt Prahar M. , McNulty Zachary , Gupta Satyandra K.
Published: September 2022

Metal additive manufacturing technology that uses arc welding technology to deposit material is called wire arc additive manufacturing. Robotic manipulators that have a large workspace to size ratio are used to enable wire arc additive manufacturing. Wire arc additive manufacturing is gaining popularity due to the fast build time achieved by the high material deposition rates. It can build large-scale parts at a faster speed compared to other metal additive manufacturing processes. Utilizing a tilting build platform along with a robotic manipulator referred to as a multi-axis setup can enhance the capability of wire arc additive manufacturing. It will allow the setup to build complex supportless geometries that are not possible otherwise. However, maintaining a constant layer height while performing multi-axis wire arc additive manufacturing is challenging due to the forces involved in the process. This paper presents a new sensor-based two-step process along with the tool trajectory generation for maintaining constant layer height while performing multi-axis wire arc additive manufacturing. As the first step, we regulate the tool trajectory velocity to minimize the variation in the layer height. In the second step, we develop a sensor-based intervention scheme to fix the variation in the layer height by introducing additional height compensation layers. Finally, we test our approach by building a few parts, including a tool for the composite layup process.
Process Optimization for Hydrothermal-Assisted Jet Fusion Additive Manufacturing of Ceramics
Authors: Fei Fan , Kirby Levi , Song Xuan
Published: September 2022

Hydrothermal-assisted jet fusion (HJF) process is a new additive manufacturing (AM) method for ceramics, which is capable of fabricating ceramic 3D structures without the need for organic binders. The HJF process selectively deposits a water-based solution into a ceramic powder bed in a layer-by-layer manner and fuses particles together through a hydrothermal mechanism. Since no organic binder is used in the HJF process, such a binder-free AM method can produce ceramic parts with less energy consumed for binder removal and has the potential to reach the material’s theoretical properties such as full density and exceptional mechanical strength. Nevertheless, the fabricated parts by the HJF process still suffers from issues, such as over fusion base-layer damage, pattern shifting, etc. In this paper, the effects of process parameters (e.g., stroke, droplet size, press number, final press, etc.) on the fabrication quality (e.g., diffusion behavior of deposited inks and shape fidelity of the fabricated parts, etc.) of the HJF process are studied. Optimum process settings are identified to alleviate those quality issues, and 3D structures with high shape fidelity were successfully fabricated to highlight the capability of the HJF process in achieving ceramic 3D structures with high accuracy and high performance.
Shape Memory Properties of 4D Printed Parts Under Cyclic Loading: Effects of Infill Characteristics and Stimulus Conditions
Authors: Han Muyue , Zhao Jing , Li Lin , Tan Miao
Published: September 2022

4D printing has spurred growing interests since its recent emergence, as it enables the fabrication of dynamic structures with reconfigurability over time when exposed to external stimuli, which is not feasible using 3D printing. The current literature on 4D printing is mainly focused on developing new materials and investigating the time-evolving properties of the printed parts, whereas the influences of process parameters on stimuli-response behaviors of 4D printed parts are not adequately explored, especially under cyclic loadings. In this study, experimental analyses are conducted to investigate the effects of infill strategies and stimulus conditions on the shape memory properties of 4D printed thermo-responsive parts. Specifically, cyclic thermo-mechanical tests are performed under different operating temperatures to investigate the shape programmability and recovery characteristic of specimens printed with various infill patterns. The results indicate that specimens printed with the rectilinear pattern exhibit better shape programmability under cyclic thermo-mechanical loadings than polygonal patterns. In addition, the decrease in shape fixity ratios over multiple cycles is also observed for all considered infill patterns. The comparative studies suggest that the increase in operating temperature within the vicinity of the material’s glass transition temperature can improve the cyclic shape memory property.
Orientation pinwheels in primary visual cortex of a highly visual marsupial
Authors: Jung Young Jun , Almasi Ali , Sun Shi H. , Yunzab Molis , Cloherty Shaun L. , Bauquier Sebastien H. , Renfree Marilyn , Meffin Hamish , Ibbotson Michael R.
Published: September 2022

Primary visual cortices in many mammalian species exhibit modular and periodic orientation preference maps arranged in pinwheel-like layouts. The role of inherited traits as opposed to environmental influences in determining this organization remains unclear. Here, we characterize the cortical organization of an Australian marsupial, revealing pinwheel organization resembling that of eutherian carnivores and primates but distinctly different from the simpler salt-and-pepper arrangement of eutherian rodents and rabbits. The divergence of marsupials from eutherians 160 million years ago and the later emergence of rodents and rabbits suggest that the salt-and-pepper structure is not the primitive ancestral form. Rather, the genetic code that enables complex pinwheel formation is likely widespread, perhaps extending back to the common therian ancestors of modern mammals.
Tailoring centripetal metamaterial with superelasticity and negative Poisson’s ratio for organic solvents adsorption
Authors: Tian Li , Yang Jinshan , You Xiao , Wang Mengmeng , Ren Xiaoyin , Zhang Xiangyu , Dong Shaoming
Published: September 2022

Graphene metamaterials with a radial-like structure and negative Poisson’s ratio (NPR) were assembled using a unique centripetal freezing technique. Driven by the centripetal temperature gradient, ice crystals were grown toward the center of an aqueous graphene dispersion and form a radially arranged skeleton. A reentrant structure was formed at the diagonal of the monolith as the ice crystals sublimate. The obtained centripetal graphene metamaterial (CGM) was endowed with NPR response. CGM maintained NPR under 50% compression, which reached a minimum (−0.18) at 10% strain. After 50 compressive cycles at 50% strain, CGM retained approximately 96% of the original compressive strength. The radial channels endowed CGM with fast absorption kinetics, and the NPR response effectively accommodated the damage caused by volume shrinkage during repeated adsorption-regeneration cycles. This strategy is an effective method for achieving NPR response and improving the mechanical properties of porous materials.
RNF220 is an E3 ubiquitin ligase for AMPA receptors to regulate synaptic transmission
Authors: Ma Pengcheng , Wan Li Pear , Li Yuwei , He Chun-Hui , Song Ning-Ning , Zhao Shiping , Wang Huishan , Ding Yu-Qiang , Mao Bingyu , Sheng Nengyin
Published: September 2022

The accurate expression of postsynaptic AMPA receptors (AMPARs) is critical for information processing in the brain, and ubiquitination is a key regulator for this biological process. However, the roles of E3 ubiquitin ligases in the regulation of AMPARs are poorly understood. Here, we find that RNF220 directly interacts with AMPARs to meditate their polyubiquitination, and RNF220 knockout specifically increases AMPAR protein levels, thereby enhancing basal synaptic activity while impairing synaptic plasticity. Moreover, depending on its E3 ubiquitin ligase activity, RNF220 represses AMPAR-mediated excitatory synaptic responses and their neuronal surface expression. Furthermore, learning and memory are altered in forebrain RNF220-deficient mice. In addition, two neuropathology-related RNF220 variants fail to repress excitatory synaptic activity because of the incapability to regulate AMPAR ubiquitination due to their attenuated interaction. Together, we identify RNF220 as an E3 ubiquitin ligase for AMPARs and establish its substantial role in excitatory synaptic transmission and brain function.
Understanding maternity waiting home uptake and scale-up within low-income and middle-income countries: a programme theory from a realist review and synthesis
Authors: Uwamahoro Nadege Sandrine , McRae Daphne , Zibrowski Elaine , Victor-Uadiale Ify , Gilmore Brynne , Bergen Nicole , Muhajarine Nazeem
Published: September 2022

Introduction

Maternity waiting homes (MWHs) link pregnant women to skilled birth attendance at health facilities. Research suggests that some MWH-facility birth interventions are more success at meeting the needs and expectations of their intended users than others. We aimed to develop theory regarding what resources work to support uptake and scale-up of MHW-facility birth interventions, how, for whom, in what contexts and why.

Methods

A four-step realist review was conducted which included development of an initial programme theory; searches for evidence; selection, appraisal and extraction of data; and analysis and data synthesis.

Results

A programme theory was developed from 106 secondary sources and 12 primary interviews with MWH implementers. The theory demonstrated that uptake and scale-up of the MWH-facility birth intervention depends on complex interactions between three adopter groups: health system stakeholders, community gatekeepers and pregnant women and their families. It describes relationships between 19 contexts, 11 mechanisms and 31 outcomes accross nine context-mechanism-outcome configurations (CMOCs) which were grouped into 3 themes: (1) Engaging stakeholders to develop, integrate, and sustain MWH-facility birth interventions, (2) Promoting and enabling MWH-facility birth utilisation and (3) Creating positive and memorable MWH-facility birth user experiences. Belief, trust, empowerment, health literacy and perceptions of safety, comfort and dignity were mechanisms that supported diffusion and adoption of the intervention within communities and health systems. Examples of resources provided by implementers to trigger mechanisms associated with each CMOC were identified.

Conclusions

Implementers of MWHs cannot merely assume that communities will collectively value an MWH-facility birth experience over delivery at home. We posit that MWH-facility birth interventions become vulnerable to under-utilisation when implementers fail to: (1) remove barriers that hinder women’s access to MWH and (2) ensure that conditions and interactions experienced within the MWH and its affiliated health facility support women to feel treated with compassion, dignity and respect.

PROSPERO registration number

CRD42020173595.
Bargaining and gendered authority: a framework to understand household decision-making about childhood vaccines in the Philippines
Authors: Wachinger Jonas , Reñosa Mark Donald C , Endoma Vivienne , Aligato Mila F , Landicho-Guevarra Jhoys , Landicho Jeniffer , Bravo Thea Andrea , McMahon Shannon A
Published: September 2022

Introduction

Targeted vaccination promotion efforts aimed at building vaccine confidence require an in-depth understanding of how and by whom decisions about vaccinating children are made. While several studies have highlighted how parents interact with other stakeholders when discussing childhood vaccination, less is known about the way in which vaccination uptake is negotiated within households.

Methods

We conducted 44 in-depth interviews with caregivers of children under five in the Philippines who had delayed or refused vaccination. Interviews were conducted between August 2020 and March 2021 and were audio-recorded, transcribed verbatim and translated into English. Notions of intra-household vaccination bargaining emerged early during systematic debriefings and were probed more pointedly throughout data collection.

Results

Parents as well as paternal and maternal families proved to be dominant stakeholders in intra-household bargaining for childhood vaccination. Although bargaining among these stakeholders was based on engrained, gender-based power imbalances, disadvantaged stakeholders could draw on a range of interrelated sources of bargaining power to nevertheless shape decision-making. Sources of bargaining power included, in descending order of their relevance for vaccination, (1) physical presence at the household (at the time of vaccination decision-making), (2) interest in the topic of vaccination and conviction of one’s own position, (3) previous vaccination and caregiving experience, and (4) access to household resources (including finances). The degree to which each household member could draw on these sources of bargaining power varied considerably over time and across households.

Conclusion

Our findings highlight how bargaining due to intra-household disagreement coins decisions regarding childhood vaccination. Considering the risks for public health associated with vaccine hesitancy globally, we advocate for acknowledging intra-household dynamics in research and practice, such as by purposefully targeting household members with decision-making capacity in vaccination promotion efforts, aligning promotion efforts with available bargaining capacity or further empowering those convinced of vaccination.
Identification of novel HLA-A*11:01-restricted HPV16 E6/E7 epitopes and T-cell receptors for HPV-related cancer immunotherapy
Authors: Xiong Chengjie , Huang Lihong , Kou Hedan , Wang Chenwei , Zeng Xiaomin , Sun Hanli , Liu Shangyuan , Wu Bin , Li Jingyao , Wang Xiaoling , Wang Zibing , Chen Lin
Published: September 2022

Background

E6 and E7 oncoproteins are considered ideal antigens of T cell therapy for human papillomavirus (HPV)-related cancers. However, little is known about the epitopes of E6 and E7 presented by HLA-A*11:01, one of the most prevalent HLA types globally, especially in Asia.

Methods

We combinedin silicoand experimental approaches to identify endogenously processed HLA-A*11:01-restricted epitopes of HPV16 E6 and E7. The identified epitopes were then used to screen available T cell receptors (TCRs) from healthy donors throughin vitrostimulation of peripheral blood mononuclear cells (PBMCs).

Results

E693-101(TTLEQQYNK, TTL) and E789-97(IVCPICSQK, IVC), two novel HLA-A*11:01-restricted T cell epitopes of HPV16, were identified to be endogenously presented on tumor cells. TTL- and IVC-specific TCRs were isolated from 11 healthy donors throughin vitrostimulation of PBMC. The key TTL and IVC residues involved in TCR-pMHC interactions were mapped, and the consensus sequence was “xxLEQxYNK” and “xVxPIxxxK.” The TTL- and IVC-specific TCRs with high functional avidity were used to generate TCR-engineered T cells, specifically recognizing and killing corresponding tumor cell lines in vitro and in vivo. In addition, TTL and IVC-specific TCR-T cells also recognized and killed HPV16+patient-derived organoids.

Conclusions

The HLA-A*11:01-restricted HPV16 E6/E7 epitopes and TCRs identified in this study may provide a new strategy for HPV-related cancer immunotherapy in HLA-A*11:01+patients.
Artificial intelligence and radiomics: fundamentals, applications, and challenges in immunotherapy
Authors: Dercle Laurent , McGale Jeremy , Sun Shawn , Marabelle Aurelien , Yeh Randy , Deutsch Eric , Mokrane Fatima-Zohra , Farwell Michael , Ammari Samy , Schoder Heiko , Zhao Binsheng , Schwartz Lawrence H
Published: September 2022

Immunotherapy offers the potential for durable clinical benefit but calls into question the association between tumor size and outcome that currently forms the basis for imaging-guided treatment. Artificial intelligence (AI) and radiomics allow for discovery of novel patterns in medical images that can increase radiology’s role in management of patients with cancer, although methodological issues in the literature limit its clinical application. Using keywords related to immunotherapy and radiomics, we performed a literature review of MEDLINE, CENTRAL, and Embase from database inception through February 2022. We removed all duplicates, non-English language reports, abstracts, reviews, editorials, perspectives, case reports, book chapters, and non-relevant studies. From the remaining articles, the following information was extracted: publication information, sample size, primary tumor site, imaging modality, primary and secondary study objectives, data collection strategy (retrospective vs prospective, single center vs multicenter), radiomic signature validation strategy, signature performance, and metrics for calculation of a Radiomics Quality Score (RQS). We identified 351 studies, of which 87 were unique reports relevant to our research question. The median (IQR) of cohort sizes was 101 (57–180). Primary stated goals for radiomics model development were prognostication (n=29, 33.3%), treatment response prediction (n=24, 27.6%), and characterization of tumor phenotype (n=14, 16.1%) or immune environment (n=13, 14.9%). Most studies were retrospective (n=75, 86.2%) and recruited patients from a single center (n=57, 65.5%). For studies with available information on model testing, most (n=54, 65.9%) used a validation set or better. Performance metrics were generally highest for radiomics signatures predicting treatment response or tumor phenotype, as opposed to immune environment and overall prognosis. Out of a possible maximum of 36 points, the median (IQR) of RQS was 12 (10–16). While a rapidly increasing number of promising results offer proof of concept that AI and radiomics could drive precision medicine approaches for a wide range of indications, standardizing the data collection as well as optimizing the methodological quality and rigor are necessary before these results can be translated into clinical practice.
Admixture mapping of severe asthma exacerbations in Hispanic/Latino children and youth
Authors: Herrera-Luis Esther , Mak Angel C Y , Perez-Garcia Javier , Martin-Gonzalez Elena , Eng Celeste , Beckman Kenneth B , Huntsman Scott , Hu Donglei , González-Pérez Ruperto , Hernández-Pérez José M , Mederos-Luis Elena , Sio Yang Yie , Poza-Guedes Paloma , Sardón Olaia , Corcuera Paula , Sánchez-Machín Inmaculada , Korta-Murua Javier , Martínez-Rivera Carlos , Mullol Joaquim , Muñoz Xavier , Valero Antonio , Sastre Joaquin , Garcia-Aymerich Judith , Llop Sabrina , Torrent Maties , Casas Maribel , Rodríguez-Santana José R , Villar Jesús , del Pozo Victoria , Lorenzo-Diaz Fabian , Williams L Keoki , Melén Erik , Chew Fook Tim , Borrell Luisa N , Burchard Esteban G , Pino-Yanes Maria
Published: September 2022

Background

In the USA, genetically admixed populations have the highest asthma prevalence and severe asthma exacerbations rates. This could be explained not only by environmental factors but also by genetic variants that exert ethnic-specific effects. However, no admixture mapping has been performed for severe asthma exacerbations.

Objective

We sought to identify genetic variants associated with severe asthma exacerbations in Hispanic/Latino subgroups by means of admixture mapping analyses and fine mapping, and to assess their transferability to other populations and potential functional roles.

Methods

We performed an admixture mapping in 1124 Puerto Rican and 625 Mexican American children with asthma. Fine-mapping of the significant peaks was performed via allelic testing of common and rare variants. We performed replication across Hispanic/Latino subgroups, and the transferability to non-Hispanic/Latino populations was assessed in 1001 African Americans, 1250 Singaporeans and 941 Europeans with asthma. The effects of the variants on gene expression and DNA methylation from whole blood were also evaluated in participants with asthma and in silico with data obtained through public databases.

Results

Genomewide significant associations of Indigenous American ancestry with severe asthma exacerbations were found at 5q32 in Mexican Americans as well as at 13q13-q13.2 and 3p13 in Puerto Ricans. The single nucleotide polymorphism (SNP) rs1144986 (C5orf46) showed consistent effects for severe asthma exacerbations across Hispanic/Latino subgroups, but it was not validated in non-Hispanics/Latinos. This SNP was associated withDPYSL3DNA methylation andSCGB3A2gene expression levels.

Conclusions

Admixture mapping study of asthma exacerbations revealed a novel locus that exhibited Hispanic/Latino-specific effects and regulatedDPYSL3andSCGB3A2.
Was the San Quintín kangaroo rat really rediscovered?
Authors: Andrade-Sánchez Jorge , Arteaga Maria Clara , Mellink Eric
Published: September 2022

The San Quintín kangaroo rat ( Dipodomys gravipes Huey, 1925) is one of the three kangaroo rats in northwestern Baja California and the largest of them in most body dimensions. After a dramatic population decline in the 1980s, it was declared as potentially extinct in the wild by Mexican law. In 2017, the species was claimed to be rediscovered, but critical data supporting the species recognition were not provided. The question remained: Was the San Quintín kangaroo rat really rediscovered? We analyzed individuals identified by us as D. gravipes to validate our identification. We compared cranial morphometric and mitochondrial data of on-purpose collected specimens with those of historic specimens and with those of sympatric kangaroo rats in Baja California, particularly the Dulzura kangaroo rat ( Dipodomys simulans (Merriam, 1904)). Cranial morphometry and body dimensions of current specimens are indistinguishable from those of historic D. gravipes, while being different from D. simulans in most dimensions. External measurements such as cranial traits adequately distinguish both species. The mitochondrial analysis revealed strong support for the species grouping of sequences of our specimens and DNA sequences of D. gravipes from the GenBank repository. This study comprises a morphometric and molecular confirmation of the presence of the species after >25 years of failures to find it.
Transistor-Level Radiation Hardening by Design Techniques in Complex Gates
Authors: Ferraz Bruno T. , Kessler Henrique , Camargo Vinícius V. A.
Published: September 2022

Single Event Transients (SETs) have become a major reliability concern for integrated circuits used in critical applications. Research to improve the radiation robustness of digital circuits has been conducted, assessing all abstraction levels (from the device up to the system). This study evaluates transistor-level radiation-hardened techniques in combinational logic, such as transistor folding, sizing and reordering. In addition, the efficiency of using supergates, including series-parallel and non-series-parallel CMOS structures, to harden the combinational logic is discussed. The dependence of input signals probability on a logic cell susceptibility to SET is assessed. Moreover, a new concept of electrical masking is introduced. The robustness of the investigated logic cells was evaluated regarding their SET rate. The CREME96 tool was used to generate the SET rates, and an electrical model was used to perform particle hit simulations. Obtained results have indicated that modifying the structure of logic gates can substantially improve circuit robustness without necessarily worsening its performance. Besides, using supergates in combinational logic design has demonstrated to be a promising hardening strategy. The most robust supergate implementation of a five-input logic function provided up to [Formula: see text] SET rate reduction regarding an approach based on standard cells, along with lower critical delay ([Formula: see text]) and average power ([Formula: see text]).
A Novel Nonisolated Quasi Z-Source Multilevel Inverter for Solar Photovoltaic Energy System Using Robust Technique: An ICSA–RPNN Technique
Authors: Santhi R. , Srinivasan A.
Published: September 2022

An efficient method primarily depending on nonisolated quasi Z-source (QZS) novel multilevel inverter (NIQZS-NMLI) topology to interconnect photovoltaic (PV) system is proposed in this paper. The proposed hybrid system is the combination of improved chameleon swarm algorithm (ICSA) and recurrent perceptron neural network (RPNN), hence it is named as ICSA–RPNN. Usually, the interface among the PV DC supply, the load is achieved through an NIQZS-NMLI topology. Here, the NIQZS-NMLI topology modeling design is increased with the new storage device to supply the largest amount of power from the PV power production system. The number of switches and full harmonic distortion of the machine are reduced through the NMLI topology, and it is used to achieve better upgrading capability, and reduce the voltage pressure on the entire active switching device has a better modulation index. At first, the objective function is described primarily depending on its controller parameters and control voltages, current, power, and modulation code. These parameters are useful to the inputs of the proposed ICSA-RPNN approach. The ICSA-RPNN methodology enhanced the voltage profile, reducing power distribution, power oscillations simultaneously distributing power to the load. The modulation load is controlled by proposed artificial intelligence (AI) mainly depends on the NIQZS-NMLI topography. In addition, the ICSA-RPNN methodology reduces the injected power, controls the voltage, current and frequency conditions of the DC hyperlink. The ICSA-RPNN approach is performed at MATLAB/Simulink site and the general performance of the output is compared to the existing systems for different load conditions.