Stages Of Assembly Research Articles

Standardized Representation of Parts and Assembly for Build Planning.

The design and construction of genetic systems, in silico, in vitro, or in vivo, often involve the handling of various pieces of DNA that exist in different forms across an assembly process: as a standalone "part" sequence, as an insert into a carrier vector, as a digested fragment, etc. Communication about these different forms of a part and their relationships is often confusing, however, because of a lack of standardized terms. Here, we present a systematic terminology and an associated set of practices for representing genetic parts at various stages of design, synthesis, and assembly. These practices are intended to represent any of the wide array of approaches based on embedding parts in carrier vectors, such as BioBricks or Type IIS methods (e.g., GoldenGate, MoClo, GoldenBraid, and PhytoBricks), and have been successfully used as a basis for cross-institutional coordination and software tooling in the iGEM Engineering Committee.

Development of Augmented Reality Learning Media in Chemistry Subject High School

This study aims to develop chemical bond Augmented Reality (AR) learning media based on Android applications and determine their feasibility. AR media is used in Chemistry class X SMA. Topics developed in this medium are covalent bonding materials and molecular shapes. This Research and Development research was conducted using the multimedia development life cycle (MDLC) model with the stages of concept, design, material collecting, assembly, testing, and distribution. At the testing stage, a feasibility test is carried out through two stages of the validation test, namely the alpha test and beta test. The results of this study indicate that: (1) AR learning media products in chemistry class X were successfully developed with covalent bonds and molecular shapes; (2) the results of testing AR learning media in chemistry Class X obtained very decent results with a percentage of 89.58% in media testing, 91.25% in material testing, and 80.20% in testing prospective users; and (3) this AR learning media received a positive response both from students as potential users and from the subject teacher concerned regarding the easy-to-understand material due to clear visualization and examples as well as an attractive appearance.

Enhancement of virtual data quality using pre-trained Bayesian transfer learning under inaccurate and insufficient measurement data

The accurate application of designed dimensions in manufacturing is crucial but complicated by certain limitations in the manufacturing process. Therefore, manufacturing and assembly conditions should be considered in product designs. However, predicting and managing the deformation quality of industrial products, composed of multiple components, is often challenging owing to part deformation during the manufacturing process and structural deformation at the assembly stage. Owing to the advancements in artificial intelligence, highly precise predictive models can be created if sufficient data are available. However, the acquisition of extensive labeled data required for model training can be expensive and time-consuming in the industrial sector. Traditional approaches such as computer-aided engineering, which are commonly used to produce virtual data, have limitations owing to uncertainties in the experimental data, making consistency correction both time-consuming and expensive. This study proposes a method for enhancing the quality of virtual data created in contexts with insufficient and inaccurate experimental data. Engineering properties were extracted from experimental data and integrated with transfer learning using a pre-trained Bayesian neural network. We applied the proposed method to a micro-LED case to predict assembly and manufacturing variations during the design phase under inaccurate and insufficient data. Consequently, the accuracy was significantly improved over the predictive model that predicted the amount of assembly deformation using only experimental data, resulting in a predictive model with an average R-squared prediction accuracy of 98.9% for the deformation resulting from the assembly.

Post-Transcriptional Features of CAR-T Cell Excessively Activated By Tonic Signaling

Introduction：Strong tonic signaling caused by spontaneous CAR aggregation is an important mechanism of CAR-T cell exhaustion which can impair the anti-tumor function. Many studies have illustrated the features of CAR-T cell activated excessively by tonic signaling at transcriptional, protein and epigenetic levels. Regulation of tonic signaling and downstream responses could enhance the anti-tumor effect. However, post-transcriptional features is little known while a lot of studies have demonstrated that post-transcripitonal processes such as exon skipping (ES), intron removal and alternative polyadenylation (APA) play critical roles in T cell activation and homeostasis. Methods and results：To investigate post-transcriptional features of CAR-T cell excessively activated by tonic signaling, we performed RNA sequencing on CAR-T cells and untransduced T cells at day6 or day12 after anti-CD3/CD28 beads stimulation. These samples were sequenced with high read depth (>80 M reads) to enable accurate quantification of alternative splicing in downstream analysis. Exon skipping events were identified by rMATS (≥10 splice junction reads per event, |dPSI|>0.1 and p value <0.05), then we predicted whether these events affect protein domains and protein-protein interactions. We performed enrichment analysis based on these affected interaction edges. From early to late stage after stimulation, CAR-T cells underwent exon skipping events which were significantly enriched in pathways such as cytokine signaling, calcium mobilization and adaptive immune system. Conversely, untransduced T cells from early to late stage also underwent amounts of ES events while the affected interactions were rarely enriched in meaningful pathways. Previous study has discovered that T cell activation could induce global reduction of intron retention (IR) level and intron-retained transcripts are less stable than fully spliced transcripts (Ni Ting et al. Nucleic acids research 2016). We found that IR level was in line with the activation level of the these groups. As CAR-T cells were continuously activated from day6 to day12, the global IR level didn't changed significantly while untransduced T cells has significantly elevated the global IR level (Fig.1). We also investigated the features of alternative polyadenylation which occurred in over 70% of mammalian mRNA genes, turning out expression of alternative polyadenylation isoforms with different 3′UTR lengths. A total of 448 genes showed a significant difference (P-value <0.05, a relative abundance change >5%）in the proximal-to-distal poly(A) site use between day6 and day12 CAR-T cells. Compared to day6, 229 genes increased use of the proximal poly(A) site and 219 genes increased use of the distal poly(A) site in day12 CAR-T cells. In untransduced T cells, we found that the number of genes showing lengthening 3′UTRs was 4.1-fold greater than the number of genes showing the opposite trend (589 vs. 143), indicating the general 3′UTR lengthening in the cell. Previous studies have described that T cell activation can cause global 3′UTR shortening and suggested that longer 3′UTR may expose more miRNA binding sites which impaired the stability of RNA (Sandberg R et. al. Science 2009). As all above post-transcriptional features we found seemed to contribute to activation signal and RNA stability, we asked whether we could prevent excessive activation and exhaustion by regulating post-transcriptional process. We treated CAR-T cells with madrasin for 72 hours which is a splicing inhibitor interfering with the early stages of spliceosome assembly. We found that madrasin at a low concentration can significantly inhibit the CAR-T cells' activation, exhaustion, terminal differentiation without affecting the apoptosis rate. Significance: We have discovered the importance of efficient post-transcriptional machinery during the process of CAR-T cell being excessively activated by tonic signaling.

Modelling and optimization of distributed assembly hybrid flowshop scheduling problem with transportation resource scheduling

In the distributed assembly flowshop scheduling problem (DAFSP), the transportation resources between the production and assembly stages are rarely scheduled. However, for production managers, the transportation stage is important as it directly influences the cooperation between the production and assembly phases. Hence, in this study, a critical variant of the DAFSP, called the distributed assembly hybrid flowshop scheduling problem with transportation resource scheduling (DAHFSPT), is evaluated. DAHFSPT considers several vehicles for component delivery, and the early assembly is allowed in the assembly site. A mixed-integer linear programming model of the problem is developed to minimize the makespan and total energy consumption simultaneously. To solve the problem, an improved multi-objective evolutionary algorithm based on decomposition (IMOEA/D) is proposed. In the IMOEA/D, a well-designed encoding method, and eight heuristics decoding methods are embedded into the initialization operator to generate a high-quality initial population. A problem-based local search operator is presented to enhance the performance of the algorithm and accelerate its convergence. In addition, an elimination-reinitialization operator is designed to avoid optimal local solutions. A total of 200 instances based on classical benchmarks are formulated to verify the effectiveness of each improvement component in the IMOEA/D. Comprehensive experiments indicate that the IMOEA/D outperforms five well-known multi-objective algorithms concerning solution quality and distribution in solving the DAHFSPT.

Bending deformation control in a laser-welded long straight structure by elastic pre-bending technique

Longitudinal bending deformation is the most typical mode of welding deformation in long-straight welded structures with asymmetric cross-sections. It is very critical for manufacturing accuracy to control the longitudinal bending deformation during the welding assembly stage. The objective of this study is to propose an elastic pre-bending technique to control the longitudinal bending deformation induced by welding heat input. Both numerical simulation technology and experimental method are employed to investigate the longitudinal bending deformation in a large-straight structure made of SUS304 stainless steel. In the current study, the effectiveness of the proposed elastic pre-bending method is verified by experiment. Simulation results show that the longitudinal bending deformation caused by welding could be reduced by >90 % by setting an appropriate value of pre-bending deformation. In addition, based on theoretical analysis and simulation results, the control mechanism of longitudinal bending deformation is clarified.

Research on digital twin framework for customized product manual assembly systems

With the increasing demand for personalized products, customization has become increasingly popular. To achieve customization and efficiency, products are always the same as those in batch production in the former stages but different in the assembly stage. Consequently, assembly is the key stage in customized production, and manual operations are necessary. Compared with automated operations, manual operations still have problems such as easy misassembly and low efficiency. The digital twin (DT) technology has the potential to monitor and solve these problems. This study proposes a framework for production line reconstruction and intelligent monitoring of customized product manual assembly based on DT. To meet the requirements of DT modeling for customized product manual assembly systems, a progressive multidimensional DT modelling method is proposed. Finally, the feasibility of the proposed modelling method and framework is verified through a case study of a customized control valve assembly system in an instrument manufacturing enterprise.

Web app for the stimulation of auditory skills in children

The existing literature identifies various situations related to hearing problems in children, such as difficulties in understanding oral language, delayed speech development, or auditory discrimination problems. In this work, we present a technological tool designed to stimulate listening skills in children from 5 to 7 years old, following the principles of Condemarin. This tool offers stimulation activities and provides immediate feedback to improve the ability to recognize, discriminate, and interpret auditory stimuli, which contributes to the development of communication skills in children. The tool we developed is a web application that is easy for therapists to install, learn, and configure. For its creation, we follow the prototype methodology, which includes the requirements, assembly, evaluation, corrections, documentation, and testing stages. We collaborate with a multidisciplinary team of experts in information technology, linguistic rehabilitation, education, and graphic design. Throughout the six phases of our process, we kept user needs in mind, resulting in a system evaluation that demonstrated high user satisfaction and good performance both in technical and interface terms. In addition, this application benefits children with language disorders and learning difficulties and children from 5 to 7 years old since it encourages the development of their communication skills.

Evaluation of segmental lining response during shield tunnel construction based on field measurements and 3D FEM simulation

Lining safety can be threatened more severely at the construction stage than at the service stage, because the loads at the construction stage are larger. This study presents an in-situ experiment for measuring the loads acting on the lining and the internal forces of the lining to investigate the lining response during both the construction and service stages. A three-dimensional (3D) finite element method (FEM) model that could simulate the main relevant components of the shield tunnel construction process was employed to gain further insight into the mechanisms of the lining response. The influences of the key segment position and assembly sequence on the lining behavior were examined through a comprehensive parametric analysis. The results showed that during the assembly stage, the insertion of a key segment resulted in the most significant increase in the axial force, followed by the assembly of an adjacent segment. The lining responses were significantly influenced by the key segment, particularly during the construction stage, whereas the assembly sequence had a limited effect on the lining responses. During the construction stage, the closer the key segment to the tunnel invert, the greater was the axial force and the smaller was the bending moment of the lining. During the construction stage, the closer the key segment to the tunnel invert, the smaller was the axial force of the tunnel lining and the greater was the bending moment. The circumferential compressive stress reached its maximum value at the joint interfaces. Finally, the jack thrust force was the greatest at the tunnel invert. The key segment should not be placed at this location.

Mpox virus infection and drug treatment modelled in human skin organoids.

Mpox virus (MPXV) primarily infects human skin to cause lesions. Currently, robust models that recapitulate skin infection by MPXV are lacking. Here we demonstrate that human induced pluripotent stem cell-derived skin organoids are susceptible to MPXV infection and support infectious virus production. Keratinocytes, the predominant cell type of the skin epithelium, effectively support MPXV infection. Using transmission electron microscopy, we visualized the four stages of intracellular virus particle assembly: crescent formation, immature virions, mature virions and wrapped virions. Transcriptional analysis showed that MPXV infection rewires the host transcriptome and triggers abundant expression of viral transcripts. Early treatment with the antiviral drug tecovirimat effectively inhibits infectious virus production and prevents host transcriptome rewiring. Delayed treatment with tecovirimat also inhibits infectious MPXV particle production, albeit to a lesser extent. This study establishes human skin organoids as a robust experimental model for studying MPXV infection, mapping virus-host interactions and testing therapeutics.

Yeast ribosome biogenesis factors Puf6 and Nog2 and ribosomal proteins uL2 and eL43 act in concert to facilitate the release of nascent large ribosomal subunits from the nucleolus.

Large ribosomal subunit precursors (pre-LSUs) are primarily synthesized in the nucleolus. At an undetermined step in their assembly, they are released into the nucleoplasm. Structural models of yeast pre-LSUs at various stages of assembly have been collected using cryo-EM. However, which cryo-EM model is closest to the final nucleolar intermediate of the LSU has yet to be determined. To elucidate the mechanisms of the release of pre-LSUs from the nucleolus, we assayed effects of depleting or knocking out two yeast ribosome biogenesis factors (RiBi factors), Puf6 and Nog2, and two ribosomal proteins, uL2 and eL43. These proteins function during or stabilize onto pre-LSUs between the late nucleolar stages to early nucleoplasmic stages of ribosome biogenesis. By characterizing the phenotype of these four mutants, we determined that a particle that is intermediate between the cryo-EM model State NE1 and State NE2 likely represents the final nucleolar assembly intermediate of the LSU. We conclude that the release of the RiBi factors Nip7, Nop2 and Spb1 and the subsequent stabilization of rRNA domains IV and V may be key triggers for the release of pre-LSUs from the nucleolus.

Patterns and repeatability of multi‐ecotype assemblages of sympatric salmonids

AbstractAimHigh repeatability among assemblages of closely related but ecologically distinct ecotypes implies predictability in evolution and assembly of communities. The conditions under which ecotype assemblages form predictably, and the reasons, have been little investigated. Here, we test whether repeatability declines as the number of ecotypes builds.LocationPostglacial lakes with a circumboreal distribution.Time PeriodData were extracted from studies published between 1982 and 2019.Major Taxa StudiedEcotype assemblages from two Salmonid genera – Salvelinus and Coregonus. Fish in postglacial lakes commonly occur as pairs of ecotypes, typically with a pelagic and a littoral/benthic form, but in Salvelinus and Coregonus, assemblages commonly contain multiple sympatric ecotypes.MethodsWe used a meta‐analysis of Salvelinus and Coregonus to empirically assess how repeatability varies across assemblages of two to seven ecotypes. We examined repeatability of use of broad niche categories as well as underlying phenotypic traits.ResultsWithin Coregonus, repeatability across multi‐ecotype assemblages did not break down with the addition of a third or fourth ecotype. However, in Salvelinus, repeatability was largely absent and independent of the number of ecotypes. Repeatability of trait frequency distributions was absent in both genera, yet associations between trait means and niche categories were evident, especially in Coregonus.Main ConclusionsThese results show that repeatability can vary greatly between lineages; that repeatability need not break down as the number of ecotypes builds; and that high repeatability of broad niche categories may result despite marked differences in the underlying frequency distribution of trait means. These findings not only affirm the presence of repeatable ecotype assembly and early stages of divergence in postglacial fishes at a global scale, but also highlight variability among taxa and underlying phenotypic traits.

The early Paleozoic Wuyi–Yunkai orogeny in South China: a collisional orogeny with a major lag in time between onset of collision and peak metamorphism in subducted continental crust

Abstract Collisional orogeny is characterized by deep subduction of continental crust and major crustal thickening, leading to high-pressure/high-temperature metamorphism and anataxis of the subducted continental crust. Since conductive heating of large slabs of cold, subducted continental crust is a slow process, heating to a temperature that is high enough to generate significant partial melting can take tens of millions of years. Where the spatial and temporal relationships are obscured due to later modification (e.g. post-collisional rifting), the peak metamorphism and magmatism may be interpreted as an orogeny that is separate from the collision, or may be interpreted as an intraplate orogeny as no contemporaneous arcs or ophiolite may be present. We propose here that this is the case for the early Paleozoic orogeny in South China. In our model, the West Cathaysia terrane of South China was part of a continent (possibly Australia) on the lower plate and collided with another continent (possibly India) in the Cambrian–Ordovician, at a late stage of Gondwana assembly, and the late Ordovician–Silurian Wuyi–Yunkai orogeny, characterized by amphibolite–granulite facies metamorphism and extensive anataxis, was a continuation of the Cambrian–Ordovician collisional orogeny. In this interpretation, the Wuyi–Yunkai orogen was part of the Kuunga orogen before Gondwana break-up.

Functional Prototype Design for a Programmable Equipment in Personalized Football Training

AbstractAssembly and testing are the last stages in the design phase to obtain proof of concept for a certain product. Although it is time and cost consuming, assembly fit and test are crucial for the future development of any complex product, unveiling potential consequences in the future product life cycle. The current paper addresses the main assembly stages, testing strategies, feedback implementation, and redesign decisions involved in the development of a programmable equipment in personalized football training. Demountable subassemblies are used for the manufacture of the final prototype, encouraging interchangeability of parts, and modularity of the final product. Coupling, gear, key, and bearing assemblies are mainly used to physically obtain the programmable equipment prototype. Since some components are bespoke and are 3D printed specifically for this product, fit tests are undertaken to ensure proper functioning of all mechanical and electronic components. Software and electronic testing are also done to both calibrate and ensure proper code functioning. Optimization of the prototype is implemented in all three main systems that make up the personalized football training equipment: mechanical, electronic, and software. The optimized functional prototype of the equipment will be subjected to endurance tests in order to evaluate the life expectancy of individual components, subassemblies, and, finally, of the general product.

Enhancing durability of automotive fuel cells via selective electrical conductivity induced by tungsten oxide layer coated directly on membrane electrode assembly.

The poor durability, attributed to catalyst corrosion during start-up/shutdown (SU/SD), is a major obstacle to the commercialization of fuel cell electric vehicles (FCEVs). We recently achieved durability enhancement under SU/SD conditions by implementing a metal-insulator transition (MIT) using proton intercalation/deintercalation in WO3. However, such oxide-supported catalysts were unsuitable for direct application to the mass production stage of membrane electrode assembly (MEA) process due to their physical and chemical properties. Here, we report a unique approach that achieves the same durability enhancement in SU/SD situations while being directly applicable to the conventional MEA fabrication process. We coated WO3 on the bipolar plate, gas diffusion layer, and MEA to investigate whether the MIT phenomenon was realized. The WO3-coated MEA demonstrated 94% performance retention during SU/SD, the highest level to our knowledge. It can directly contribute to enhancing the durability of commercial FCEVs and be immediately applied to the MEA mass production process.

Modern Methods for Modelling Bolted Joints at the Assembly Stage – A Systematic Review

The main aim of the paper is to catalog ways of modeling bolted joints and introducing bolt preload using the finite element method. The paper presents models of bolted joints published in the current decade (i.e. after 1 January 2021 and up to 10 May 2023) in journals of the world's largest scientific publishers, such as: Elsevier, Springer, and MDPI, among others. Reporting of the systematic review was carried out based on PRISMA guidelines. The databases were searched with the EBSCO multi-search engine for the following keywords: bolted joint model, bolted connection model, preload, and finite element method. Additionally, the search results were narrowed down to peer-reviewed papers from the discipline of engineering and written in English. This yielded 2,712 records for further analysis. After removing duplicates from this group, screening was carried out, based on which 1,476 records were excluded from the study. For the remaining group of reports, an eligibility assessment was performed, after which a further 210 reports were excluded from the study. Finally, 86 papers were included in the review. As a result of their examination, six groups of simplified fastener models currently used in the modeling of bolted joints at the assembly stage were described.

Structural insights into the mechanism of GTP initiation of microtubule assembly

In eukaryotes, the dynamic assembly of microtubules (MT) plays an important role in numerous cellular processes. The underlying mechanism of GTP triggering MT assembly is still unknown. Here, we present cryo-EM structures of tubulin heterodimer at their GTP- and GDP-bound states, intermediate assembly states of GTP-tubulin, and final assembly stages of MT. Both GTP- and GDP-tubulin heterodimers adopt similar curved conformations with subtle flexibility differences. In head-to-tail oligomers of tubulin heterodimers, the inter-dimer interface of GDP-tubulin exhibits greater flexibility, particularly in tangential bending. Cryo-EM of the intermediate assembly states reveals two types of tubulin lateral contacts, “Tube-bond” and “MT-bond”. Further, molecular dynamics (MD) simulations show that GTP triggers lateral contact formation in MT assembly in multiple sequential steps, gradually straightening the curved tubulin heterodimers. Therefore, we propose a flexible model of GTP-initiated MT assembly, including the formation of longitudinal and lateral contacts, to explain the nucleation and assembly of MT.

Concept of lipid droplet biogenesis

Lipid droplets (LD) are functionally conserved fat storage organelles found in all cell types. LDs have a unique structure comprising of a hydrophobic core of neutral lipids (fat), triacylglycerol (TAG) and cholesterol esters (CE) surrounded by a phospholipid monolayer. LD surface is decorated by a multitude of proteins and enzymes rendering this compartment functional. Accumulating evidence suggests that LDs originate from discrete ER-subdomains, demarcated by the lipodystrophy protein seipin, however, the mechanisms of which are not well understood. LD biogenesis factors together with biophysical properties of the ER membrane orchestrate spatiotemporal regulation of LD nucleation and growth at specific ER subdomains in response to metabolic cues. Defects in LD formation manifests in several human pathologies, including obesity, lipodystrophy, ectopic fat accumulation, and insulin resistance. Here, we review recent advances in understanding the molecular events during initial stages of eukaryotic LD assembly and discuss the critical role of factors that ensure fidelity of this process.

Mathematical model and augmented simulated annealing algorithm for mixed-model assembly job shop scheduling problem with batch transfer

In the mixed-model assembly job-shops, all the components are transferred in batches from the processing stage to the assembly stage to reduce transportation costs and timely satisfy the assembly material requirements. However, batch transfer in such a workshop has not received due attention in the current literature. Thus, this work addresses the mixed-model assembly job-shop scheduling problem with batch transfer via a mathematical model and an augmented simulated annealing algorithm to minimize manufacturing and transportation costs. The mathematical model takes batch transfer constraints into account and constructs the temporal and spatial links among the processing, transfer, and assembly stages. Production sequencing knowledge and batch transfer knowledge are first extracted via gene expression programming algorithm and clustering method and then implanted into the algorithmic operators in the form of rules and strategies to directly identify the promising solution space. Besides, eleven neighborhood structures including the critical component-based and batch-based ones, are designed to enhance the exploitation ability. A restart mechanism considering crossover and tempering helps to get out of local optima. Experimental results indicate that by adopting the extracted knowledge, problem-specific neighborhood structures, and restart mechanism, the proposed algorithm significantly outperforms other comparison algorithms in fixing the studied problem.

Mathematical model and adaptive simulated annealing algorithm for mixed-model assembly job-shop scheduling with lot streaming

Mixed-model assembly and lot streaming are two key technologies to improve efficiency and reduce setups in a multi-variety and small-batch discrete manufacturing environment. Yet few studies consider the two technologies in assembly job-shop scheduling problems. Thus, this paper investigates the mixed-model assembly job-shop scheduling problem with lot streaming, which contains two closely coordinated stages with differentiated production lot size: the processing stage with lot streaming and the mixed-model assembly stage with single-piece flow. To tackle this problem, a mathematical model including new constraints i.e. production sequence constraints within/among sublots, sequence-dependent setup constraints between sublots and mixed-model assembly constraints, is developed to establish the temporal and spatial links between the processing and assembly stages. Besides, an adaptive simulated annealing algorithm is proposed. In this algorithm, a sublot sequence rule considering sublot and assembly features is discovered via gene expression programming to promote the performance of initial solutions; a Q-learning-based temperature control mechanism is designed to adaptively adjust the acceptance probability of inferior solutions and accordingly avoid local optima; an adaptive selection mechanism of neighborhood operators is designed to increase the chance of finding potential solutions; an adaptive adjustment mechanism of neighborhood size is put forward to balance computing resources and the coverage of neighborhood space. Experimental results show that both the discovered rule and the adaptive mechanisms are effective, and the developed algorithm is more adapt to fix the studied problem than other state-of-the-art algorithms.