bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toolpath Synthesis and Mechanical Properties in Multiplexed Fused Filament Fabrication
Authors: Cleeman Jeremy , Jackson Adrian , Patel Anandkumar , Malhotra Rajiv 
Published: August 2024

Abstract
Material Extrusion additive manufacturing (MatEx) based on Fused Filament Fabrication (FFF) enables inexpensive bottom-up fabrication of thermoplastics and thermoplastic composites for structural, biomedical, energy, and tooling applications. The to-scale realization of these lab-scale innovations in MatEx depends significantly on mass customization, i.e., increasing the overall process throughput (including that of post-processing) while retaining high resolution and 3D geometric capability that is crucial to additive manufacturing. This paper addresses a throughput-resolution-geometry tradeoff that limits such mass customization via a Multiplexed FFF (MF3) approach that combines a unique dynamic-extrusion based toolpath strategy with the existing multi-extruder-single-gantry machine architecture. MF3 has been demonstrated in one recent work. But this past effort does not enable geometrically generalizable and automated synthesis of the atypical MF3 toolpath, does not investigate the unconventional scaling of throughput while considering partial infills that are common in additive manufacturing, and does not explore the mechanical effects of the section-section junctions created by MF3. This work establishes an automated and generalizable toolpath synthesis approach and derives analytical laws for build time reduction, both of which are prerequisites for rational process planning. A multi-extruder multi-section thermal model is created to reveal the atypical temperature history of section junctions in MF3 and is combined with mechanical testing and modelling to deconvolute geometric and thermal effects on the mechanical behavior of the section-section junctions.
An Island Type Novel Scan Pattern With Non-Linear Island Intersections for Laser Powder Bed Fusion Additive Manufacturing Processes
Authors: Roney Md Saidur Rahman , Ahsan A. M. M. Nazmul , Sezer Hayri , Kaul Sudhir 
Published: August 2024

Abstract
Thermal gradient and solidification time dictate the prominent mechanical properties and printing qualities of metal parts produced through the Laser Powder Bed Fusion (LPBF) additive manufacturing (AM) techniques. Printing defects such as warpage, delamination, and cracking originate from the thermal history of the printed parts. The relatively smaller heat source (laser) following a given scan pattern results in rapid solidification and uneven distribution of thermal energy, which in turn develops residual stresses in the printed parts. Through island-type scanning, the rapid solidification phenomenon is inhibited as it allocates the thermal energy within the islands thereby raising the surface temperature. In this paper, a novel island-type scan pattern with non-linear island boundary is proposed to distribute the Heat Affected Zones (HAZs) along the lateral direction of the island span. The proposed pattern is island-type and zigzag that reflects the regular hexagonal shape arranged periodically along each island span, creating nonlinear intersections between two adjacent islands. The effect of the proposed scan pattern on residual stress development is then investigated through a numerical approach and compared with that of the existing Zigzag and Island Zigzag scan patterns. The simulation results exhibit comparable characteristics of the proposed scan pattern with a 6.67% reduction in residual stress achieved as compared to the other two scan patterns.
In-Situ Process Monitoring and Optimization for Extrusion-Based Silicone Additive Manufacturing
Authors: Ma Dingyifei , Tian Xiaoqing , Chang Tianlong , Hussain Shahid , Xia Lian , Han Jiang 
Published: August 2024

Abstract
The lack of direct process control of silicone material extrusion (MEX) limits the accuracy and design complexity of printed structures. In this paper, an iterative process monitoring system for silicone MEX that enables in-situ quality monitoring and optimization is presented and validated. To achieve in-situ quality monitoring, a laser profile sensor is integrated into the 3D printing platform to measure dimensional errors. The process includes virgin printing, scanning, analyzing, judging, and modified printing. Strands are initially printed and scanned step by step with the coordination of motion and sensing systems to obtain a point cloud with 3-dimensional coordinates. Data are corrected, standardized, and analyzed section by section instead of using an image process to improve efficiency and reserve information in the height direction. Centre, width, and height information are extracted for each strand cross-section. Noise and anomalies are then removed by a clustering algorithm for the center points to obtain the actual trajectory centerline and distribution of strand width along the trajectory. To achieve in-situ optimization for errors in trajectory, strand width, and height, the trajectory and process parameters are modified in the next print. The trajectory is corrected by applying the opposite trajectory deviation error vector. The feed rate is modified according to our previously proposed strand profile model that maps the process parameters to the strand cross-section geometry parameters. Compared with direct printing without in-situ quality monitoring and optimization, the overlap between the actual and the target strand was improved by 18%. The presented method demonstrates the feasibility and capability to improve accuracy and reduce errors.
Electrohydrodynamic Jet Printing Mechanisms and Applications to Flexible Electronic Devices
Authors: Chang Tianlong , Wang Zaiyu , Tian Xiaoqing , Ma Dingyifei , Hussain Shahid , Xia Lian , Han Jiang 
Published: August 2024

Abstract
In the field of biomedical devices and their applications, electrohydrodynamic jet (E-Jet) printing plays a crucial role in the fabrication of next-generation fine medical devices by virtue of its high resolution and precise control. This study focuses on optimizing the electrohydrodynamic jet printing fabrication process for flexible circuits using silver nanoparticles (AgNPs) on flexible substrates. In order to control the relationship between high preparation accuracy and low energy consumption, the working and geometrical parameters of the experimental process, such as voltage, printing speed and working height, are then explored in relation to the prepared circuits. The different states of the printing process are demonstrated in conjunction with computational fluid dynamics studies, and the causes of Taylor cone formation, cone-jet generation, jet rupture and droplet expansion are explained. The results show that the preparation of silver nanoparticle circuits using E-Jet printing technology can achieve micron-level discrimination and low energy consumption flexible circuits by regulating the process parameters, and the prepared flexible silver circuits have achieved 500 severe cyclic bending tests of 120° in the bending cycle. The results of this study provide a simple and stable solution for the preparation of E-Jet printed flexible circuits and offer a viable strategy for the fabrication of high-resolution biomedical devices.
Coupled Eulerian-Lagrangian Thermomechanical Model to Predict Residual Stress During Additive Friction Stir Deposition of Aluminum 6061
Authors: Mathews Ritin , Karandikar Jaydeep , Tyler Christopher , Smith Scott , Schmitz Tony 
Published: August 2024

Abstract
Additive friction stir deposition (AFSD) is a solid-state additive manufacturing process that is increasing in popularity thanks to the absence of high temperature effects in the deposited material. Due to the large amount of material flow, conventional Lagrangian (finite element) models are incapable of capturing realistic material physics involved in the process. Alternatively, although Eulerian (computational fluid dynamics) models capture large material flow, they cannot predict the mechanical (stress-strain) response of the material. Existing AFSD modeling works in the literature either apply simplifying assumptions or do not predict the mechanical response of the material. To address this research gap, a coupled Eulerian-Lagrangian (CEL) model is developed to simulate AFSD of aluminum 6061 and predict the thermomechanical response of the material during and after deposition. This physics-based model captures the influences of significant material flow, adiabatic heating due to plastic deformation and frictional heating during deposition and reasonably predicts temperature and residual stress.
Brief Paper: Model-Free Adaptive Spindle Speed Regulation for Mitigation of Machining Vibrations
Authors: Bahtiyar Kaan , Sencer Burak 
Published: August 2024

Abstract
This paper presents novel adaptive spindle speed control strategies to minimize machining vibrations. Machining processes suffer from forced and chatter vibrations that deteriorate surface finish, reduce tool life and can damage the machine components. Model-based process planning strategies are used to minimize the effect of these unwanted vibrations. These approaches require conducting modal (tap) testing to be performed on the machine tool and developing machining process model to determine the forced vibration levels and to generate stability lobe diagrams for chatter-free cutting conditions. Although such model-based strategies are effective in process planning and determining optimal spindle speed and depth-of-cut pairs, these model-guided strategies suffer from key bottlenecks; namely, 1) they require expert knowledge that is not widely available in small-to-medium sized enterprises and 2) their effectiveness depends on the accuracy of the employed models. Thus, the majority of machining industries utilize know-how-based process planning to mitigate vibrations in machining. This paper proposes practical and model-free self-optimizing (adaptive) spindle-speed regulation strategies that minimize machining vibrations through in-situ vibration (acceleration) measurements. Two approaches are presented aimed at mitigating the effect of both forced and chatter vibrations by monitoring the acceleration levels during machining. Strategy-I utilizes a dither signal to determine the best spindle speed to minimize overall machining vibrations, whereas strategy-II is a dither-free approach and utilizes least squares fitting to seek the optimal spindle speed. Both approaches can determine chatter-free cutting conditions and also minimize forced vibration levels for a better surface finish. Simulation studies are presented in this brief paper to showcase their effectiveness.
Aqueous Wet Etching of Silicon With Alkali Metal Hydroxides
Authors: Hasan Md Mahmudul , Rahman Faiz 
Published: August 2024

Abstract
Silicon etching is a process that is regularly employed in the semiconductor industry for many applications ranging from micromachining on the sub-millimeter scale to intricate pattern formation in tens of nanometer regime. Wet etching is used for bulk silicon removal. Such etching processes, generally, involve multiple chemical reactions where a liquid solution of etching agents removes surface atoms of silicon through chemical or electrochemical redox reactions at the substrate-etchant interface. Many wet etching processes are anisotropic, and thus the wet etching of silicon with hydroxide solutions tends to be direction or crystalline plane specific, allowing for directional control and reduced undercutting of any etch mask. An additional advantage of metal hydroxide etchants rise from their selective nature of extremely poor etch rate towards the basic oxide of silicon. This makes growing the hard mask of SiO2 a very cost effect step in the wet etching process. NaOH and KOH solutions are well known wet etching agents that offer inexpensive alternatives to anisotropic dry etching but are often either difficult to control (etch rate-wise) or result in rough etched surfaces. Only through better understanding of the chemical reaction mechanisms, i.e. the role of alkali metal cations and water molecules during the wet etching process more controllability and desired etch surface profiles can be achieved. This study summarizes the results from a series of wet etch processes with all the five different group 1 alkali metal oxides and discusses in detail how different types of group 1 metal ions impact the dynamics of the chemical reactions in the aqueous medium. Wet etching assisted by smaller cations like Li+ tend to be more controllable while larger cations like Cs+ result in much faster etch rates. Surfactants added to fast etching metal hydroxides result in finer sidewalls and smoothened etched surface on silicon. Later in the paper, the effect of microwave irradiation on the surface tension, structural arrangement of water molecules and its application in anisotropic etching are highlighted. Step by step details of the experiments are provided in the materials and methods section making the study easy to understand. Line profile plots, optical images, SEM micrographs and XRD intensity plots are presented throughout the report to support the given explanations. Research findings from the study experimentally establish a trend for anisotropic etch rates of silicon substrate with aqueous solutions of all the group 1 alkali metal hydroxides. Silicon etch rate increases down the group.
Strain-specific differences in the interactions of the cucumber mosaic virus 2b protein with the viral 1a and host Argonaute 1 proteins
Authors: Crawshaw Sam , Watt Lewis G. , Murphy Alex M. , Carr John P. 
Published: August 2024

ABSTRACT

The cucumber mosaic virus (CMV) 2b protein is a potent counter-defense factor and symptom determinant that inhibits antiviral silencing by titrating short double-stranded RNAs. Expression of the CMV subgroup IA strain Fny-CMV 2b protein in transgenic
Arabidopsis thaliana
plants disrupts microRNA-mediated cleavage of host mRNAs by binding Argonaute 1 (AGO1), leading to symptom-like phenotypes. This also triggers AGO2-mediated antiviral resistance and resistance to CMV’s aphid vectors. However, in authentic viral infections, the Fny-CMV 1a protein modulates 2b-AGO1 interactions, inhibiting induction of AGO2-mediated virus resistance and aphid resistance. Contrastingly, 2b proteins encoded by the subgroup II strain LS-CMV and the recently discovered subgroup IA strain Ho-CMV induce no symptoms. Confocal laser scanning microscopy, bimolecular fluorescence complementation, and co-immunoprecipitation showed that Fny-CMV and Ho-CMV 2b proteins interact with Fny-CMV and LS-CMV 1a proteins, while the CMV-LS 2b protein cannot. However, Fny-CMV, Ho-CMV, and LS-CMV 2b proteins, all interacted with AGO1, but while AGO1-Fny2b complexes occurred in the nucleus and cytoplasm, corresponding AGO1-2b complexes for LS-CMV and Ho-CMV accumulated almost exclusively in nuclei.
AGO2
transcript accumulation was used to assess the inhibition of AGO1-mediated mRNA degradation. Fny-CMV 2b induced a fivefold increase in
AGO2
accumulation, but LS-CMV and Ho-CMV 2b proteins induced only twofold increases. Thus, these 2b proteins bind AGO1 but are less effective at inhibiting AGO1 activity. We conclude that the intracellular localization of 2b-AGO1 complexes influences the degree to which a 2b protein inhibits microRNA-mediated host mRNA degradation and that cytoplasmic AGO1 has the strongest influence on miRNA-mediated cellular mRNA turnover.

IMPORTANCE

The cucumber mosaic virus (CMV) 2b protein was among the first discovered viral suppressors of RNA silencing. It has additional pro-viral functions through effects on plant defensive signaling pathways mediated by salicylic acid and jasmonic acid, the abscisic acid pathway and virus-induced drought resistance, and on host plant interactions with insect vectors. Many of these effects occur due to interaction with the important host RNA silencing component Argonaute 1 (AGO1). It was thought that only 2b proteins of “severe” CMV strains interacted with AGO1 and inhibited its microRNA-mediated “slicing” of cellular mRNAs and that the lack of interaction with AGO1 explained the moderate symptoms typically seen in plants infected with mild CMV strains. Our work overthrows this paradigm by showing that mild strain CMV 2b proteins can interact with AGO1, but their
in vivo
localization prevents them from interacting with AGO1 molecules present in the infected cell cytoplasm.
Zebrafish
phd1
enhances mavs-mediated antiviral responses in a hydroxylation-independent manner
Authors: Yu Guangqing , Yuan Le , Li Xiong , Zuo Mingzhong , Wang Rui , Chen Mengjuan , Liu Yuqing , Liu Xing , Xiao Wuhan 
Published: August 2024

ABSTRACT

PHD1 is a member of the prolyl hydroxylase domain protein (PHD1–4) family, which plays a prominent role in the post-translational modification of its target proteins by hydroxylating proline residues. The best-characterized targets of PHD1 are hypoxia-inducible factor α (HIF-1α and HIF-2α), two master regulators of the hypoxia signaling pathway. In this study, we show that zebrafish phd1 positively regulates mavs-mediated antiviral innate immunity. Overexpression of
phd1
enhances the cellular antiviral response. Consistently, zebrafish lacking
phd1
are more susceptible to spring viremia of carp virus infection. Further assays indicate that phd1 interacts with mavs through the C-terminal transmembrane domain of mavs and promotes mavs aggregation. In addition, zebrafish phd1 attenuates K48-linked polyubiquitination of mavs, leading to stabilization of mavs. However, the enzymatic activity of phd1 is not required for phd1 to activate mavs. In conclusion, this study reveals a novel function of phd1 in the regulation of antiviral innate immunity.

IMPORTANCE

PHD1 is a key regulator of the hypoxia signaling pathway, but its role in antiviral innate immunity is largely unknown. In this study, we found that zebrafish
phd1
enhances cellular antiviral responses in a hydroxylation-independent manner. Phd1 interacts with mavs through the C-terminal transmembrane domain of mavs and promotes mavs aggregation. In addition, phd1 attenuates K48-linked polyubiquitination of mavs, leading to stabilization of mavs. Zebrafish lacking
phd1
are more susceptible to spring viremia of carp virus infection. These findings reveal a novel role for phd1 in the regulation of mavs-mediated antiviral innate immunity.
Prevotella timonensis
degrades the vaginal epithelial glycocalyx through high fucosidase and sialidase activities
Authors: Segui-Perez Celia , de Jongh Rivka , Jonkergouw Robin L. W. , Pelayo Paula , Balskus Emily P. , Zomer Aldert , Strijbis Karin 
Published: August 2024

ABSTRACT

Bacterial vaginosis (BV) is a polymicrobial infection of the female reproductive tract. BV is characterized by replacement of health-associated
Lactobacillus
species by diverse anerobic bacteria, including the well-known
Gardnerella vaginalis. Prevotella timonensis,
and
Prevotella bivia
are anerobes that are found in a significant number of BV patients, but their contributions to the disease process remain to be determined. Defining characteristics of anerobic overgrowth in BV are adherence to the mucosal surface and the increased activity of mucin-degrading enzymes such as sialidases in vaginal secretions. We demonstrate that
P. timonensis,
but not
P. bivia,
strongly adheres to vaginal and endocervical cells to a similar level as
G. vaginalis
but did not elicit a comparable proinflammatory epithelial response. The
P. timonensis
genome uniquely encodes a large set of mucus-degrading enzymes, including four putative fucosidases and two putative sialidases, PtNanH1 and PtNanH2. Enzyme assays demonstrated that fucosidase and sialidase activities in
P. timonensis
cell-bound and secreted fractions were significantly higher than for other vaginal anerobes. In infection assays,
P. timonensis
efficiently removed fucose and α2,3- and α2,6-linked sialic acid moieties from the epithelial glycocalyx. Recombinantly expressed
P. timonensis
NanH1 and NanH2 cleaved α2,3 and α2,6-linked sialic acids from the epithelial surface, and sialic acid removal by
P. timonensis
could be blocked using inhibitors. This study demonstrates that
P. timonensis
has distinct virulence-related properties that include initial adhesion and a high capacity for mucin degradation at the vaginal epithelial mucosal surface. Our results underline the importance of understanding the role of different anerobic bacteria in BV.

IMPORTANCE

Bacterial vaginosis (BV) is a common vaginal infection that affects a significant proportion of women and is associated with reduced fertility and increased risk of secondary infections.
Gardnerella vaginalis
is the most well-known BV-associated bacterium, but
Prevotella
species including
P. timonensis
and
P. bivia
may also play an important role. We showed that, similar to
G. vaginalis
,
P. timonensis
adhered well to the vaginal epithelium, suggesting that both bacteria could be important in the first stage of infection. Compared to the other bacteria,
P. timonensis
was unique in efficiently removing the protective mucin sugars that cover the vaginal epithelium. These results underscore that vaginal bacteria play different roles in the initiation and development of BV.
Transcriptional regulators
SP110
and
SP140
modulate inflammatory response genes in
Mycobacterium tuberculosis
-infected human macrophages
Authors: Nakamura Hajime , Hikichi Haruka , Seto Shintaro , Hijikata Minako , Keicho Naoto 
Published: August 2024

ABSTRACT

Understanding the functions of human transcriptional regulatory genes
SP110
and
SP140
during
Mycobacterium tuberculosis
infection is crucial; in a mouse model, homologous genes
Sp110
and
Sp140
have been shown to negatively regulate inflammatory response genes, including the type I interferon (IFN) response. The reduction of these genes in mice is associated with susceptibility to
M. tuberculosis
infection and the development of necrotizing granulomatous lesions. To investigate the involvement of
SP110
and
SP140
in human inflammatory response, we analyzed their regulatory manner in THP-1 macrophages infected with
M. tuberculosis
. Genome-wide transcriptional profiling revealed that the depletion of
SP110
and/or
SP140
impaired the induction of gene expression associated with inflammatory responses, including IFN response genes, although it had little effect on the intracellular proliferation of
M. tuberculosis
. By contrast, genes related to phosphorylation were upregulated in infected macrophages with
SP110
and/or
SP140
knockdown, but downregulated in infected control macrophages without their knockdown. Reverse transcription-quantitative PCR and ELISA further confirmed the impairment of the induction of IFN response genes by the depletion of
SP110
and/or
SP140
in
M. tuberculosis
-infected macrophages. These findings suggest that human
SP110
and
SP140
act as positive regulators for genes associated with inflammatory responses in
M. tuberculosis
-infected macrophages.

IMPORTANCE

Tuberculosis (TB) is one of the most serious infectious diseases, with high morbidity and mortality worldwide. C3HeB/FeJ mice are widely utilized for evaluating anti-TB drugs because their drug sensitivity and pathology during
M. tuberculosis
infection resemble those of human TB, including the development of necrotizing granulomas. Downregulation of the transcriptional regulatory genes
Sp110
and
Sp140
in C3HeB/FeJ mice has been demonstrated to activate gene expression associated with inflammatory responses during
M. tuberculosis
infection, resulting in susceptibility to the infection. Here, we examined the regulatory manner of
SP110
and
SP140
using transcriptomic analysis in
M. tuberculosis
-infected human macrophages. Depletion of
SP110
and/or
SP140
in
M. tuberculosis
-infected THP-1 macrophages impaired the induction of gene expression associated with inflammatory responses, including interferon response genes, compared with that in control macrophages. These results suggest that human
SP110
and
SP140
act as positive regulators for genes associated with inflammatory responses upon
M. tuberculosis
infection.