Simple Assembly Research Articles

Improved USER cloning for TALE assembly and its application to base editing.

Transcription activator-like effectors (TALEs) have been widely used for genome editing, transcriptional regulation, and locus-specific DNA imaging. However, TALEs are difficult to handle in routine laboratories because of their complexity and the considerable time consumed in TALE construction. Here, we described a simple and rapid TALE assembly method based on uracil-specific excision reagent (USER) cloning. Polymerase chain reaction was amplified with TALE trimer templates and deoxyuridine-containing primers. The products were treated with USER at 37°C for 30 min, followed by the treatment of T4 DNA Ligase at 16°C for 30 min. The TALE trimer unit could be rejoined hierarchically to form complete TALE expression vectors with high efficiency. This method was adopted to construct TALE-deaminases, which were used in combination with Cas9 nickases to generate efficient C-to-T or A-to-G base editing while eliminating predictable DNA off-target effects. This improved USER assembly is a simple, rapid, and laboratory-friendly TALE construction technique that will be valuable for DNA targeting.

Assessing by Simulation the Effect of Process Variability in the SALB-1 Problem

The simple assembly line balancing (SALB) problem is a significant challenge faced by industries across various sectors aiming to optimise production line efficiency and resource allocation. One important issue when the decision-maker balances a line is how to keep the cycle time under a given time across all cells, even though there is variability in some parameters. When there are stochastic elements, some approaches use constraint relaxation, intervals for the stochastic parameters, and fuzzy numbers. In this paper, a three-part algorithm is proposed that first solves the balancing problem without considering stochastic parameters; then, using simulation, it measures the effect of some parameters (in this case, the inter-arrival time, processing times, speed of the material handling system which is manually performed by the workers in the cell, and the number of workers who perform the tasks on the machines); finally, the add-on OptQuest in SIMIO solves an optimisation problem to constrain the cycle time using the stochastic parameters as decision variables. A Gearbox instance from literature is solved with 15 tasks and 14 precedence rules to test the proposed approach. The deterministic balancing problem is solved optimally using the open solver GLPK and the Pyomo programming language, and, with simulation, the proposed algorithm keeps the cycle time less than or equal to 70 s in the presence of variability and deterministic inter-arrival time. Meanwhile, with stochastic inter-arrival time, the maximum cell cycle is 72.04 s. The reader can download the source code and the simulation models from the GitHub page of the authors.

Durably dual superlyophobic cationic guar gum‑calcium complex decorated cellulose fabrics for on-demand oil/water separation

The removal to oils from water has become a global issue because of the growing of wastewater discharge and unceasing appearance of oil leaks. Herein, a kind of durably dual superlyophobic (superhydrophobic under oil and superoleophobic under water) cotton fabric (CF) was fabricated via simple assembly route that introduced guar hydroxypropyltrimonium chloride‑calcium (GHTC-Ca) chelate compound on the fabric surface. The coated CF exhibits good resistance to mechanical abrasion, corrosive aqueous solution, high temperature, and organic solvent immersion. Furthermore, due to prewetting-caused superoleophobicity underwater and superhydrophobicity underoil, the as-prepared CF can selectively separate both heavy oils and light oils in water under extremely harsh conditions with separation efficiencies as high as 98.7 % and 98.4 %, respectively. More importantly, the as-prepared fabrics are able to remove dispersed oil droplets from oil-in-water emulsions and water droplets from water-in-oil emulsions with separation efficiency of over 89 % and 91.4 %, respectively. Hence, this prominent separation performance suggests a good application prospect of GHTC-Ca functionalized CF in oily water purification.

Woven Carbon-Fiber-Reinforced Polymer Tubular Mesh Reinforcement of Hollow High-Performance Concrete Beams.

This article presents woven carbon-fiber-reinforced polymer (CFRP) tubular mesh used as a reinforcement on the inner surface of hollow beams made of high-performance concrete (HPC). The tubular mesh was designed to serve as both the tensile and shear reinforcement of hollow beams intended for the construction of small self-supporting structures that could be assembled without mechanization. The reinforcement was prepared with a tri-axial weaving machine from carbon filament yarn and was homogenized using epoxy resin. The interaction of the composite reinforcement with the cementitious matrix was investigated, and the surface of the reinforcement was modified using silica sand and polyvinyl alcohol (PVA) fibers to improve cohesion. The sand coating enhanced bond strength, resulting in the significantly higher flexural strength of the hollow beam of 128%. The PVA fibers had a lower positive effect of 64% on the flexural strength but improved the ductility of the beam. Individual beams were connected by gluing steel parts directly inside the hollow core of the HPC beam. This procedure provides good interaction between the CFRP reinforcement and the glued steel insert and allows for the fast and simple assembly of structures. The weaving of additional layers of the CFRP reinforcement around HPC beams was also explored. A small structure made of the hollow HPC beams with inner composite reinforcement was constructed to demonstrate the possibilities of the presented technology.

Hierarchical-structure and high-modulus aramid nanofiber membrane protective layer achieving high-performance lithium metal anode

Uniform lithium deposition and a stable solid electrolyte interface (SEI) film are crucial for realizing long-term stable operation of lithium metal batteries. Herein, aramid nanofiber (ANF) membrane with abundant amide bonds and hierarchical structure as an artificial solid electrolyte interface (SEI) was constructed through a simple two-step assembly strategy, which can effectively improve the interfacial compatibility and inhibit the growth of Li dendrites. A large number of polar amide bonds in ANF films can serve as anchor points to interact with Li+. The layered structure and hierarchical porosity of ANF films exhibits significantly improved mechanical strength and ability to suppress dendrites. Therefore, the constructed ANF membrane can homogenize the lithium flux during lithium plating/stripping process, inhibit the formation of hot spots, and promote the formation of a uniform SEI layer under these synergistic effects. The ANF modified Li (ANF@Li) anodes exhibit significantly improved electrochemical performance, stable cycling for 2500 h at high current density (10 mA cm−2) and 2500 h at high capacity (10 mAh cm−2). In addition, ANF@Li anodes showed a long life over 2800 h at 5 mA cm−2 and 10 mAh cm−2, which enables the ANF@Li anode to be the promising candidate for the next generation of high-power-density and high-energy–density batteries.

An exact method to incorporate ergonomic risks in Assembly Line Balancing Problems

Since ergonomic risks related to the tasks performed by each worker are generally neglected when solving the Simple Assembly Line Balancing Problem (SALBP) or partially treated in post-processing, this paper aims to incorporate ergonomic issues natively in the decision process (ErgoSALBP). For such a problem, we present a novel Mixed-Integer Linear Programming (MILP) model that linearizes and incorporates into the SALBP the Occupational Repetitive Action (OCRA). This well-known method gives ergonomic risk indicators for musculoskeletal disorders. A lexicographical approach to address the problem is proposed, where the minimum number of stations is obtained for SALBP and used as a starting point to solve a type-F ErgoSALBP (feasibility problem) focused on satisfying the maximum ergonomic risk workload. Once the exact solution is found, we establish an objective function to smooth the ergonomic risk distribution among stations. We tested a total of 2160 instances with up to 297 tasks. Our method was able to solve 94% of all instances optimally. The share of solutions found with only green stations (the ideal ergonomic condition) was 87%, surpassing the state of the art. For the instances where the model did not converge to a solution within the time limit, we present a procedure to assess the optimality gap. Furthermore, the model can be embedded as a building block for other assembly line configurations. Finally, the results provide trade-off insights for managers: the average OCRA for the line improves as the cycle time increases, which may positively impact workers’ satisfaction and product quality in the long run.

The Current Progress of Tetrahedral DNA Nanostructure for Antibacterial Application and Bone Tissue Regeneration.

Recently, programmable assembly technologies have enabled the application of DNA in the creation of new nanomaterials with unprecedented functionality. One of the most common DNA nanostructures is the tetrahedral DNA nanostructure (TDN), which has attracted great interest worldwide due to its high stability, simple assembly procedure, high predictability, perfect programmability, and excellent biocompatibility. The unique spatial structure of TDN allows it to penetrate cell membranes in abundance and regulate cellular biological properties as a natural genetic material. Previous studies have demonstrated that TDNs can regulate various cellular biological properties, including promoting cells proliferation, migration and differentiation, inhibiting cells apoptosis, as well as possessing anti-inflammation and immunomodulatory capabilities. Furthermore, functional molecules can be easily modified at the vertices of DNA tetrahedron, DNA double helix structure, DNA tetrahedral arms or DNA tetrahedral cage structure, enabling TDN to be used as a nanocarrier for a variety of biological applications, including targeted therapies, molecular diagnosis, biosensing, antibacterial treatment, antitumor strategies, and tissue regeneration. In this review, we mainly focus on the current progress of TDN-based nanomaterials for antimicrobial applications, bone and cartilage tissue repair and regeneration. The synthesis and characterization of TDN, as well as the biological merits are introduced. In addition, the challenges and prospects of TDN-based nanomaterials are also discussed.

A polarization‐insensitive ultra‐wideband absorber based on hybrid structure

AbstractWith the continuous improvement of detection technology, the survivability of targets on the battlefield is facing great challenges. Consequently, microwave absorbers with stealth characteristics are of important research value to modern military. Aim at solving the problems of narrow bandwidth or complex structure, an implementation model of ultra‐wideband (UWB) absorber based on hybrid structure is proposed. In this letter, a polarization‐insensitive ultra‐wideband absorber (PIUWA) is designed, manufactured, and characterized, which has a good absorptivity of more than 90% ranges from 4 to 24.53GHz (the fractional bandwidth [FBW] is 144%) by triggering multiple resonance peaks in the hybrid structure. In addition, the subwavelength periodicity of the PIUWA is theoretically beneficial to the angular stability under full‐wave polarizations. The operating mechanism of the PIUWA is demonstrated by the equivalent circuit model and the correctness of the design is verified by experimental measurements. This letter contributes to the approach of designing and fabricating UWB microwave absorbers with high absorptivity, good angular stability, and simpler assembly procedure.

Self-Assembly of Cysteine into Nanofibrils Precedes Cystine Crystal Formation: Implications for Aggregation Inhibition.

The self-association of metabolites into well-ordered assemblies at the nanoscale has significant biological and medical implications. The thiol-containing amino acid cysteine (CYS) can assemble into amyloid-like nanofibrils, and its oxidized form, the disulfide-bonded cystine (CTE), forms hexagonal crystals as those found in cystinuria due to metabolic disorder. Yet, there have been no attempts to connect these two phenomena, especially the fibril-to-crystal transition. Here, we reveal that these are not separated events, and the CYS-forming amyloid fibrils are mechanistically linked to hexagonal CTE crystals. For the first time, we demonstrated that cysteine fibrils are a prerequisite for forming cystine crystals, as observed experimentally. To further understand this mechanism, we studied the effects of thiol-containing cystinuria drugs (tiopronin, TIO; and d-penicillamine, PEN) and the canonical epigallocatechin gallate (EGCG) amyloid inhibitor on fibril formation by CYS. The thiol-containing drugs do not solely interact with monomeric CYS via disulfide bond formation but can disrupt amyloid formation by targeting CYS oligomers. On the other hand, EGCG forms inhibitor-dominant complexes (more than one EGCG molecule per cysteine unit) to prevent CYS fibril formation. Interestingly, while CYS can be oxidized into CTE, the thiol drugs can reduce CTE back to CYS. We thus suggest that the formation of crystals in cystinuria could be halted at the initial stage by targeting CYS fibril formation as an alternative to solubilizing the water-insoluble hexagonal CTE crystals at a later stage. Taken together, we depicted a complex hierarchical organization in a simple amino acid assembly with implications for therapeutic intervention.

Biomimetic thermoresponsive superstructures by colloidal soft-and-hard co-assembly.

Soft-and-hard hybrid structures are ubiquitous in biological systems and have inspired the design of man-made mechanical devices, actuators, and robots. The realization of these structures, however, has been challenging at microscale, where material integration and actuation become exceedingly less practical. Here, through simple colloidal assembly, we create microscale superstructures consisting of soft and hard materials, which, serving as microactuators, have thermoresponsive shape-transforming properties. In this case, anisotropic metal-organic framework (MOF) particles as the hard components are integrated with liquid droplets, forming spine-mimicking colloidal chains via valence-limited assembly. The chains, with alternating soft and hard segments, are referred to as MicroSpine and can reversibly change shape, switching between straight and curved states through a thermoresponsive swelling/deswelling mechanism. By solidification of the liquid parts within a chain with prescribed patterns, we design various chain morphologies, such as "colloidal arms," with controlled actuating behaviors. The chains are further used to build colloidal capsules, which encapsulate and release guests by the temperature-programmed actuation.

Efficiency Improvement of Automotive Assembly Lines Using Simple Assembly Line Balancing Problem Type-E

Efficiency Improvement of Automotive Assembly Lines Using Simple Assembly Line Balancing Problem Type-E

Benchmarking of Stainless Steel Cube Neutron Leakage in Research Center Rez

Integral experiments covering neutron leakage from geometrically simple assemblies with a 252Cf source inside are very valuable tools usable in the validation of transport cross-section data since geometric uncertainties play a much smaller role in simple geometric assemblies than in complex assemblies as for example reactor pressure vessel geometry. Since 252Cf spontaneous fission is a standard neutron source, the uncertainties connected with the source neutron spectrum can be even neglected. The paper refers to validation efforts of neutron leakage from an ~50 × 50 × 50-cm stainless steel block in the Research Center Rez. Both the neutron leakage flux at a distance of 1 m from the center of the cubical assembly using stilbene spectrometry and activation rates at different positions of the assembly were evaluated. In addition to experiments, main sources of uncertainty were identified and evaluated. The results of the stilbene measurements are consistent with the activation measurement results.

Interface engineering SnS2/MXene Nb2C self-powered photodetectors with high responsivity and detectivity

Research on two-dimensional (2D) materials and their van der Waals heterostructures (vdWHs) has generated a lot of interest in the fields of electronics and optoelectronics. However, the construction of 2D heterostructures remains a challenge because the most widely used deterministic placement method to perform 2D layer stacking often suffers from erratic control of lattice orientation over lattice orientations. Herein, a new 2D/2D SnS2/MXene Nb2C heterostructure for high-performance photodetectors (PDs) was designed and prepared by using a simple electrostatic assembly process. It was demonstrated that the combination of Nb2C MXene nanosheets (NSs) and SnS2 NSs significantly improved the performance of PDs by enhancing the charge transfer, carrier density, light adsorption, as well as by decreasing band bending edge and charge recombination. The SnS2/Nb2C PDs exhibited remarkable responsivity (102.44 μA/W) and ultrahigh specific detectivity (7.48 × 1012 Jones) at zero external bias under a 365 nm laser at level Ⅳ. Additionally, comprehensive investigations of energy level diagram derived from both experimental measurements and density functional theory calculations provided further insights of such photodetector system. This simple and reliable fabrication strategy opens a new avenue for the large-scale production of low-cost and high-quality MXenes-based heterogeneous bond for next-generation electronic and optoelectronic applications.

Enhancing photocatalytic cleavage of C[sbnd]C bonds in lignin model substrates by ternary nanocomposite of g-C3N4/rGO/CdS using rGO as electronic mediators

Depolymerizing lignin into aromatic monomers with high yield and selectivity via photocatalysis remains a challenging task. Herein, we introduced reduced graphene oxide (rGO) nanosheets as solid electronic mediators and successfully synthesized g-C3N4/rGO/CdS ternary nanocomposites using a simple multi-step assembly strategy. The photocatalysts can efficiently break the CC bond of lignin under simulated sunlight conditions. The characterization results demonstrate that the loading of CdS effectively enhances the light absorption range and accelerates the transfer of photogenerated charge carriers. Simultaneously, the introduction of rGO inhibits the recombination of electron-hole pairs. When using the β-O-4 model substrate, a 95% conversion rate could be achieved with yields of 71% benzaldehyde and 69% phenyl formate, which are 3.09 times and 3.63 times higher than that of pure g-C3N4, respectively. Our research highlights the importance of energy band structure engineering and electronic mediator design in developing efficient photocatalysts for breaking CC bonds of lignin.

Analysis of the simple assembly line balancing problem complexity

The simple assembly line balancing problem (SALBP) involves the determination of the assignment of elementary assembly operations to the workstations of the assembly line for the manufacture of a final product, with the objective of maximising assembly efficiency. In addition to its practicality, the SALBP can be considered as an extension of the bin packing problem (BPP) to account for the precedence relations between items. These constraints introduce an ordering component to the problem, which increases the complexity of SALBP resolution. However, previous studies indicated that precedence constraints do not play an important role in the capacity of state-of-the-art procedures to solve benchmark instances to optimality.In this study, we analysed the influences of different features of an SALBP instance on the performance of state-of-the-art solution methods for the abovementioned problem. First, we provide an alternative proof of complexity for the SALBP that uses precedence constraints to demonstrate its non-deterministic polynomial time (NP)-complete status, followed by a new set of benchmark instances directed towards an empirical analysis of the different features of SALBP instances. The experimental results revealed that the packing features of the SALBP are a major source of the perceived difficulty for any instance; however, precedence constraints play a role in the performance of these solution procedures. Specifically, the number of precedence constraints plays an important role in the results obtained from state-of-the-art methods. In addition to the analysis, certain issues that were identified in the publicly available implementations of the state-of-the-art method for resolving this problem were addressed in this study.

The Application of the Gibson Assembly Method in the Production of Two pKLS3 Vector-Derived Infectious Clones of Foot-and-Mouth Disease Virus.

The construction of a full-length infectious clone, essential for molecular virological study and vaccine development, is quite a challenge for viruses with long genomes or possessing complex nucleotide sequence structures. Herein, we have constructed infectious clones of foot-and-mouth disease virus (FMDV) types O and A by joining each viral coding region with our pKLS3 vector in a single isothermal reaction using Gibson Assembly (GA). pKLS3 is a 4.3-kb FMDV minigenome. To achieve optimal conditions for the DNA joining, each FMDV coding sequence was divided into two overlapping fragments of approximately 3.8 and 3.2 kb, respectively. Both DNA fragments contain the introduced linker sequences for assembly with the linearized pKLS3 vector. FMDV infectious clones were produced upon directly transfecting the GA reaction into baby hamster kidney-21 (BHK-21) cells. After passing in BHK-21 cells, both rescued FMDVs (rO189 and rNP05) demonstrated growth kinetics and antigenicity similar to their parental viruses. Thus far, this is the first report on GA-derived, full-length infectious FMDV cDNA clones. This simple DNA assembly method and the FMDV minigenome would facilitate the construction of FMDV infectious clones and enable genetic manipulation for FMDV research and custom-made FMDV vaccine production.

Integrating real-time manufacturing data into a novel serial two-stage adaptive alternate genetic fireworks algorithm for solving stochastic type-II simple assembly line balancing problem

Due to various interference factors, a pre-planned assembly scheme and its cycle time can be disturbed, resulting in the failure of product delivery on schedule. However, when assembly data of the production line can be obtained in real time, the balance of the assembly line could be dynamically adjusted in case of experiencing serious interferences to optimize its cycle time in time and improve its production efficiency. Therefore, this paper proposes a dynamic rebalancing framework by integrating real time manufacturing data into a novel serial two-stage adaptive alternate genetic fireworks algorithm for solving a stochastic type-II simple assembly line balancing problem (SSALBP-II). MES (manufacturing execution system) is used to obtain some real time data such as the resource status, operation information and task information and to judge abnormal phenomenon and the overdue delivery caused by interferences. On this basis, the stochastic type-II simple assembly line balance model is constructed, with a new serial two-stage adaptive alternate genetic fireworks algorithm (STAGFA). This new algorithm can incorporate both genetic algorithm and fireworks algorithm to solve the model according to the transformation of population diversity discrimination index. Through the comparison between STAGFA and other algorithms such as fireworks algorithm, genetic algorithm, other improved intelligent algorithms, it is proved that the STAGFA is effective and superior in solving the assembly line (re)balance problem. Then, the rebalanced scheme verified by simulation is dispatched to control the physical assembly line and realize dynamic rebalancing cycle time effectively.

Silicon assisted synthesis of high-purity Ca3Al2O6 carrier towards scale-up of Ca-based carbon dioxide capture materials

Aluminium-stabilized calcium-based materials are currently an excellent solution for capturing CO2 directly from industrial flue gas. However, there is still no report on the technology of low-cost and large-scale assembly of Ca3Al2O6 and CaO. In this study, we innovatively put forward a silicon-assisted strategy to facilely synthesize high-purity Ca3Al2O6 and evaluate its cyclic performance for stabilizing uptake CO2 after assembly. With regard to the Si/Al ratio of 0.2, Ca3Al2O6 was prepared selectively among 850–900 °C, with only 5.2% CaO residually. The introduction of silicon inhibited the formation of Ca5Al6O14 by-products and the mechanism of silicon at the calcium-aluminum interface was also explained by systematic characterization. The Ca3Al2O6 modified sorbent with simple assembly showed extremely high cycle stability improvement compared with the pure precipitated calcium carbonate derived CaO. These works provide technical guidance for the industrial scale-up of the rational design of Al-stabilized calcium-based adsorption materials.

R-SALSA: A branch, bound, and remember algorithm for the workload smoothing problem on simple assembly lines

We consider a simple assembly line balancing problem with given cycle time and number of stations. A quadratic objective function based on a so-called smoothness index SX levels the workloads of the stations. For this problem, called SALBP-SX, only a few solution procedures have been proposed in literature so far. In this paper, we extend and improve the branch-and-bound procedure SALSA (Simple Assembly Line Smoothing Algorithm) of Walter et al. (2021) to a bidirectional branch, bound, and remember algorithm called R-SALSA (R for remember). Like SALSA, it is based on a dynamic programming scheme which pre-determines potential workloads of the stations and provides a construction plan for possible station loads. This scheme is extended by the new concept of supporters and preventers which significantly enhances branching, bounding, and logical tests. Furthermore, a tailored heuristic that searches for improved initial solutions, a bidirectional branching scheme and additional dominance rules are integrated. In extensive computational experiments, we find out that our new procedure clearly outperforms all former exact solution procedures on benchmark data sets with up to 1000 tasks.

Noise Isolation System for Indoor Industrial Ventilation

The prevalence of hearing loss among workers in Ecuador is concerning, with up to 40% affected. One of the root causes is the lack of insulation in sources of noise generation. This study presents a practical solution to reduce noise contamination in indoor industrial facilities and to extend the usability of functional old equipment by enabling the addition of accessories, specifically in the sanding and classification areas of an agglomerate manufacturing industry. An isolation camera was designed and implemented using a combination of insulating materials to reduce the noise of a main ventilator and to ensure compliance with local noise regulations. The design and simulation were carried out using CAD tools and the finite element method (FEM) to ensure a simple assembly design, and the camera was manufactured using rapid prototyping tools with lightweight and cost-effective materials, such as wood, foam, and metal. The camera was tested in situ, and its effectiveness was evaluated through functional tests and noise level measurements. The implementation of the camera resulted in a 16% reduction in pressure noise and a 95% reduction in noise frequency. With the additional use of earmuffs, the pressure reduction improved to 44%. These values ensured that noise levels remained 27% below the limit set by Decree 2393, significantly reducing the impact of noise on workers.