Template Effect Research Articles

Comparison of four CAD-CAM guides for preparing guiding planes of removable partial dentures

Background and objectiveTo evaluate the effect of guiding structure and 3D-printing material of CAD-CAM guides on the accuracy of guiding planes preparation. MethodsFour types of computer-aided design and computer-aided manufacturing (CAD-CAM) guides for preparing guiding planes of removable partial denture (RPD) were designed in two types of guiding structures (triple-constraint and single-plane constraint) and were 3D printed using resin and cobalt-chromium (Co–Cr) alloy. Guiding plane preparation of identical resin casts was performed using CAD-CAM guides (resin template, metal template, resin guided device, and metal guide device) in four test groups and by freehand in the control group (n = 22 per group). All prepared casts were then scanned (Test) and aligned to the reference cast with designed guiding planes. 3D compare analysis was performed and root-mean-square (RMS) values were calculated for assessing the 3D trueness and 3D precision of guiding plane preparation. The angle between the prepared guiding plane (Test) and the designed path of placement of RPD (Reference) was measured for evaluating the direction trueness. ResultsRMS values of the metal template group for 3D trueness (39.7 ± 14.6 μm) and 3D precision (28.6 ± 6.8 μm) were significantly lower than that of other groups (p < .05). For direction trueness, the metal template group showed the least angle deviation (1.09 ± 0.56°), and the freehand group demonstrated the largest angle deviation (7.03 ± 2.83°). ConclusionsThe Co–Cr alloy guides with triple-constraint guiding structure can assist to prepare accurate guiding planes of RPD.

Supramolecular Template-Assisted Catalytic [2+2] Photocycloaddition in Homogeneous Solution

Supramolecular Template-Assisted Catalytic [2+2] Photocycloaddition in Homogeneous Solution

Recyclable visible-light photocatalytic composite materials based on tubular Au/TiO2/SiO2 ternary nanocomposites for removal of organic pollutants from water

The highly active free radicals generated by semiconductor materials in the photocatalytic technology can achieve efficient degradation of organic pollutants. Tubular Au/TiO2/SiO2 ternary nanocomposite is fabricated under high-temperature ablation via the sacrificial template and noble metal deposition. SiO2 is deposited to inhibit the growth of grain size of TiO2. The tubular structure can effectively increase the scattering times and improve the utilization of visible-light. Au nanoparticles (Au NPs) absorb visible-light and promote the formation of photogeneration-hole pairs. Besides, Au NPs can also be used as an electron acceptor to delay the recombination rate of photogeneration electron-hole pairs, and improve the photocatalytic activity. Furthermore, the polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) gel was used to load and immobilize TiO2-based catalytic materials, and the composite gel still has a good photocatalytic activity with favorable cyclability. This work opens up a new opportunity for designing the photocatalytic composite material with long-term catalytic stability and excellent reusability.

Self-Assembly of Polystyrene-b-poly(2-vinylpyridine)/Chloroauric Acid at the Liquid/Liquid Interface.

The self-assembly of polystyrene-block-poly(2-vinylpyridine) at the liquid/liquid interface has been systematically investigated to develop a series of primary morphologies of the aggregates. The block copolymers self-assembled into large areas of nanodot arrays, parallel nanostrands, layered films, parallel nanobelts, honeycomb monolayers, and foams by reacting with chloroauric acid, depending on the molecular structure of the block copolymers and the amount of chloroauric acid. The formation of the first four ordered structures resulted from interfacial adsorption and self-assembly, and nucleation and epitaxial growth. The latter two structures were attributed to the water hole templating effect and spontaneous interfacial emulsification, respectively. This work provides insight into the self-assembly behavior of block copolymers at the interface and provides a facile approach for fabricating functional structures.

Electrochemical deposition of Si nano-spheres from water contaminated ionic liquid at room temperature: Structural evolution and growth mechanism

• Electrochemical deposition of Si from water contaminated ionic liquid. • Templating effect from bound water-ionic liquid assembly. • Formation of Si Nano-spheres depending on the surface chemistry of the substrate. Si nano-spheres have been electrodeposited at room temperature on polycrystalline Au and graphene coated Cu substrate potentiostatically using SiCl 4 as precursor in water contaminated ionic liquid. Detail cyclic voltammetric studies show that a two-step process is involved for the electro-reduction of Si 4+ to elemental Si. The electrodeposition takes place in the over-potential domain at −1.5 V (vs. Pt) for both the working substrates. Formation of Si nano-spheres is found to be governed by the templating effect of bound water structures in BMImTf 2 N in the presence of SiCl 4 . While the distribution of particle size is broad for both the substrates, the average particle size varies from 170–180 nm for Au and graphene coated Cu substrates. XRD results show poor crystalline to amorphous nature of the Si nano-spheres which is supported by TEM studies and band-gap energy estimation. XPS results confirm the deposition of elemental Si with trace of surface oxygenated species. The growth of Si nano-spheres on Au substrate is found to follow first order kinetics while a second order kinetics seems to present the case for the deposition on graphene coated Cu substrate.

Three-Dimensional TiO2 Film Deposited by ALD on Porous Metallic Scaffold for 3D Li-Ion Micro-Batteries: A Road towards Ultra-High Capacity Electrode

To power the next generation of miniaturized electronic devices, the energy storage capability of Li-ion micro-batteries has to be significantly improved and the fabrication of high performance 3D electrodes is mandatory. Here we show how to carefully match the design of efficient 3D scaffold based on metallic porous template with the deposition parameters of titanium dioxide films made from thermal Atomic Layer Deposition method for designing efficient 3D electrodes for Li-ion micro-batteries. A 3D electrode made from Pt porous scaffold coated with 150 nm-thick anatase TiO2 film reaches a high surface capacity value up to 1600 μAh.cm−2 at C/12 with a good cycling stability during 100 cycles.

Strongly Enhanced Growth of High-Temperature Superconducting Films on an Advanced Metallic Template

We demonstrate a straightforward and easily applied technique for growing BaZrO3 doped YBa2Cu3O6+x films of highly improved quality on a commercially used buffered metallic template by pulsed laser deposition. Our method relies on reducing the grain size of the target material, which completely prevents the transfer of the harmful grain boundaries or weak links from the substrate through the buffer layers on the deposited film. We have also observed a great improvement in the self-assembly of BaZrO3 dopants, and the critical current density is increased in the high temperature range up to 40%. As an extra benefit, our method allows us to increasing the growth rate of the film by 25%. We have discussed the results comprehensively and provided quantitative insight into the underlying mechanisms. The presented technique can be considered a groundbreaking advancement for the vastly growing coated conductor industry.

Recent Advances in the Synthesis of Inorganic Materials Using Environmentally Friendly Media.

Deep Eutectic Solvents have gained a lot of attention in the last few years because of their vast applicability in a large number of technological processes, the simplicity of their preparation and their high biocompatibility and harmlessness. One of the fields where DES prove to be particularly valuable is the synthesis and modification of inorganic materials—in particular, nanoparticles. In this field, the inherent structural inhomogeneity of DES results in a marked templating effect, which has led to an increasing number of studies focusing on exploiting these new reaction media to prepare nanomaterials. This review aims to provide a summary of the numerous and most recent achievements made in this area, reporting several examples of the newest mixtures obtained by mixing molecules originating from natural feedstocks, as well as linking them to the more consolidated methods that use “classical” DES, such as reline.

Controlling the crystallinity of HfO2 thin film using the surface energy-driven phase stabilization and template effect

Phase transition of HfO2 thin film has been investigated to demonstrate desirable electrical properties, such as high dielectric constant or ferroelectricity, however, the most of results exhibited a limitation on enhancing the crystallinity because of employing dopant. In this study, the crystallization behavior in the thin film was investigated in the intrinsic and extrinsic aspects. In the laminated structure, highly crystallized tetragonal phased HfO2 was obtained by controlling the layer thickness and adapting the template effect for intrinsic and extrinsic crystallization, respectively, without using dopant. Moreover, by the phase composition analysis, the dielectric constant of various crystal structures of HfO2 thin film, tetragonal, monoclinic, and amorphous phases, were revealed using the data obtained from the real deposited thin film by atomic layer deposition process, not from the theoretical calculation.

Chirality Transfer from Chiral Mesoporous Silica to Perovskite CsPbBr 3 Nanocrystals: The Role of Chiral Confinement

Chirality Transfer from Chiral Mesoporous Silica to Perovskite CsPbBr ₃ Nanocrystals: The Role of Chiral Confinement

Synthesis, characterization of SnO2 three-dimensional microbars decorated with nanostructures and electrical properties of PMMA-SnO2 nanocomposites

Novel Tin Oxide (SnO2) three-dimensional microbars (3D: L≈10 µm × B≈1 µm × T≈1 µm) decorated with nanostructures (<100 nm) on the surface were synthesized using a template and surfactant free simple reaction method. Effect of calcination temperature on SnO2 structures were investigated. At non-calcinated condition, dense aggregated particles covers the surface of micro bars. The aggregated surface particles disintegrate to form random networks of nanoparticles at 200 ºC and at 400 ºC individual clusters of nanoparticles were formed. A rutile cassiterite tetragonal crystal structure of SnO2 was observed using X-ray diffraction (XRD). The SnO2 micro-nano structures were analysed by UV-Visible (UV-Vis) spectroscopy and was found to have an average energy band gap of 3.07 eV. Fourier Transform Infra-Red (FTIR) spectroscopy was used to identify the presence of functional groups. Micro-nanostructures were identified using Field Emission-Scanning Electron Microscopy (FE-SEM) with elemental analysis obtained from Energy Dispersive X-ray Analysis (EDX) spectroscopy. Electrically conducting polymer nanocomposites were fabricated using Poly Methyl Methacrylate (PMMA) as matrix and SnO2 micro-nano structures as the conducting fillers. Alternating current (AC) electrical properties of PMMA-SnO2 nanocomposite films were investigated using Impedance Spectroscopy. Effect of SnO2 loading and effect of frequency on the electrical properties were studied. Percolation threshold of the composites was found to be at 1 wt% of SnO2 and exhibited a conductivity of 2.3×10−8 S/cm with 2 wt% SnO2 loading.

Molecular dynamics of C–S–H production in graphene oxide environment

Abstract The process of calcium silicate hydrate (C–S–H) generation in graphene oxide (GO) nanoslits was investigated via molecular dynamics simulations using the structural polymerization reaction of silica chains in the synthesis of silica gels. The structural evolution of C–S–H, radial distribution functions, chemical components, and distribution of Q n units in the system were analyzed to investigate the influence of GO on the early growth mechanism of C–S–H and compare the structural differences of C–S–H in the presence and absence of GO. The results showed that the proportion of silicon atoms bonded to bridge-site oxygen atoms in the C–S–H structure increased in the presence of oxygen-containing graphene groups. Ion adsorption in the GO surface layer led to an increase in the degree of polymerization of C–S–H. The nucleation and templating effects of GO were confirmed, revealing the intrinsic mechanism for the formation of GO-modified reinforced cementitious materials.

Anatase/Rutile homojunction quantum dots anchored on g-C3N4 nanosheets for antibiotics degradation in seawater matrice via coupled adsorption-photocatalysis: Mechanism insight and toxicity evaluation

• Anatase/rutile homojunction QDs anchored on g-C 3 N 4 is obtained by template method. • A formation process of A-R QDs/g-C 3 N 4 (TCN-150) is performed. • TCN-150 shows coupled adsorption-photocatalysis activity to OTC removal in seawater. • Toxicity of OTC and its photocatalytic intermediates are evaluated. • Adsorption-photocatalysis synergistic mechanism of TCN-150 is proposed. In this work, a facile two-step approach involving a templated solvothermal reaction and post-pyrolysis was developed for fabrication of ternary heterojunctions of anatase/rutile quantum dots (QDs)/g-C 3 N 4 (TCN-150), which shows well coupled adsorption and photocatalytic activity. The encapsulation of hydrolyzed titanium precursors by P123 polymer on the surface of exfoliated g-C 3 N 4 nanosheets produced anatase/rutile homojunction QDs (7–8 nm)/g-C 3 N 4 heterostructural lamellas, while the subsequent pyrolysis resulted in amorphous carbon layers stacking on g-C 3 N 4 . The adsorption occurs on the carbon layers, while the photocatalysis proceeds on the conduction band of g-C 3 N 4 and valence band of anatase, which gave free radicals of ∙O 2 − and ∙OH for antibiotics decomposition, respectively. Formation of mixed anatase/rutile phases and amorphous carbon in the composite promoted the oxytetracycline (OTC) removal in dynamic flow conditions, with efficiencies about 46.8 and 3.8 times than that of g-C 3 N 4 and TiO 2 respectively, owing to facilitated photogenerated charge separation and transfer, as well as the synergy between adsorption and photocatalysis. The toxicity evaluation of detected final intermediates in the proposed OTC degradation pathways showed decreased acute toxicity of LD 50 and reduced mutagenicity, confirming weaken toxicities of intermediate solutions after visible-light irradiation for 120 min, and this demonstrated a huge potential of TCN-150 as an eco-friendly photocatalyst for practical applications.

Cofactors-like peptide self-assembly exhibiting the enhanced catalytic activity in the peptide-metal nanocatalysts

The peptide self-assembly would be expected to be as the assistance of metallic nanocatalysts to promote the catalytic reaction, attracting limited attention, but being highly anticipated. Herein, we proposed and verified an alternative strategy for enhancing the catalytic activity of the 4-nitrophenol reduction as a model reaction, by optimizing and constructing “cofactors” inspired amyloid peptide self-assembly applied in the peptide-metal nanocatalysts as the template due to the potential superiority of substrate binding. Amyloid peptide self-assembled membrane exhibited better enhanced catalytic activity, compared to peptide nanofibers as the template in the peptide-gold nanocatalysts. The optimized amyloid peptide was designated by molecular dynamic simulation to display the relative strongest interaction with specific substrate and the relative good template effect on the enhanced catalytic activity was also proved accordingly. This work may shed light on the future design and construction of novel enzyme mimics with dramatic enhanced catalytic activity by peptide assembly-metal nanocatalysts.

Microstructure and properties of the AlCrMoZrTi/(AlCrMoZrTi)N multilayer high-entropy nitride ceramics films deposited by reactive RF sputtering

The AlCrMoZrTi/(AlCrMoZrTi)N multilayer high-entropy nitride ceramic films (HENCFs) fabricated by reactive RF magnetron sputtering presented (200) preferentially oriented FCC crystal structures. With the increase in the modulation period, the nitrogen content and surface roughness of the multilayer films gradually increased, the template effect between the nanocrystalline and amorphous forms was weakened, and the multilayer interface structure decreased. The S4 film with a modulation period of 1500 nm had the highest hardness and modulus (16.6 and 225.7 GPa, respectively) and the highest H/E* and H3/E*2 values. The results of friction experiments showed that the S1 film with the smallest modulation period had a stable friction coefficient and small wear rate on both Si and Cu substrates, and it exhibited the best friction and wear performance due to its low surface roughness, high toughness and compressive yield resistance, and dense multilayer structure. The friction mechanisms of the HECNFs on Si and Cu substrates were mainly adhesive wear, abrasive wear, and a small amount of oxidative wear.

Two Birds with One Stone: A NaCl-Assisted Strategy toward MoTe2 Nanosheets Nanoconfined in 3D Porous Carbon Network for Sodium-Ion Battery Anode

The larger van der Waals interlayer distance of MoTe2 is favorable for Na+ insertion/extraction when MoTe2 is used as sodium-ion battery (SIB) anode. However, engineering of stoichiometric 2D MoTe2 and high-conductivity carbon networks with robust interfacial bonding for SIB anodes is still a great challenge and rarely reported. In this work, high-crystallized 2D MoTe2 nanosheets nanoconfined by interconnected 3D porous carbon networks (indicated with 2D-MoTe2@3DPCN) for SIB anode is successfully constructed via a facile NaCl-assisted strategy. During the synthesis process, the NaCl demonstrates the two birds with one stone effect: the template effect for the formation of interconnected 3D hierarchical porous carbon networks, and the promoting effect of chalcogen atom exchange for in situ conversion from 2D-MoS2 to 2D-MoTe2, which was validated by both experimental results and first-principles simulations. The as-constructed unique architecture not only facilitates both ions and electrons transportation and diffusion throughout the overall electrode, but also can effectively prevent the aggregation of MoTe2 nanosheets and buffer their volume change during the insertion and extraction of Na+. As a result, 2D-MoTe2@3DPCN as SIB anode displays high reversible discharge specific capacity (∼412 mA h g−1 at 100 mA g−1), excellent rate capability (213.8 mA h g−1 at 20 A g−1) and outstanding long cycle life even at high charge/discharge current density (the capacity retention after 3000 cycles is 77.4% at 20 A g−1). This work provides a new path to construct MoTe2-based composites for application in energy-storage fields and beyond.

Pristine and Defective 2D Borophene/Graphene Heterostructure as the Potential Anode of Lithium‐Ion Batteries

AbstractBorophene has received much attention due to its unique structure and electronic properties. However, the application of borophene has been limited by the template effect of the growth metal substrate. A stable borophene/graphene (B/G) heterostructure is designed and prepared by the resonance ball milling method and one‐step molding strategy to realize the application of borophene in the lithium‐ion battery for the first time. Graphene serves as a supporting substrate for borophene, and the B/G anode has a better specific capacity and rate performance than the reduced graphene (G) oxide skeleton. By comparing the electrochemical performance of boron powder samples under different ball milling times, it is found that the anode of B/G heterostructure with 6 h boron powder has the largest specific capacity of 192.3 mAh g–1, which is 39% higher than that of the graphene framework. Oxidation functional groups on the surface of borophene are beneficial for the rate performance of the anode. And the influence of the surface functional groups of borophene are analyzed on the diffusion performance through the first principles. It is believed that the B/G has potential for further applications in the field of lithium‐ion batteries.

Considerations for homology-based DNA repair in mosquitoes: Impact of sequence heterology and donor template source.

The increasing prevalence of insecticide resistance and the ongoing global burden of vector-borne diseases have encouraged new efforts in mosquito control. For Aedes aegypti, the most important arboviral vector, integration rates achieved in Cas9-based knock-ins so far have been rather low, highlighting the need to understand gene conversion patterns and other factors that influence homology-directed repair (HDR) events in this species. In this study, we report the effects of sequence mismatches or donor template forms on integration rates. We found that modest sequence differences between construct homology arms [DNA sequence in the donor template which resembles the region flanking the target cut] and genomic target comprising 1.2% nucleotide dissimilarity (heterology) significantly reduced integration rates. While most integrations (59–88%) from plasmid templates were the result of canonical [on target, perfect repair] HDR events, no canonical events were identified from other donor types (i.e. ssDNA, biotinylated ds/ssDNA). Sequencing of the transgene flanking region in 69 individuals with canonical integrations revealed 60% of conversion tracts to be unidirectional and extend up to 220 bp proximal to the break, though in three individuals bidirectional conversion of up to 725 bp was observed.

Nitrogen doped porous carbon polyhedral supported Fe and Ni dual-metal single-atomic catalysts: template-free and metal ligand-free sysnthesis with microwave-assistance and d-band center modulating for boosted ORR catalysis in zinc-air batteries

Constructing dual-metal single-atom catalysts (DSAs) now stands for a unique and worthwhile strategy for developing high-efficiency electrocatalysts for oxygen reduction reaction (ORR). However, the facile synthesis of DSAs uniformly located on nitrogen porous carbon materials is still challenging. Herein, Fe and Ni dual-metal single-atomic active sites uniformly located on nitrogen doped porous carbon polyhedrals (FeNi-DSAs-PNCH) are successfully prepared by a facile and rapid microwave-assisted adsorption and subsequent pyrolysis process with free template and free metal ligand. The FeNi-DSAs-PNCH catalyst exhibits boosted ORR activity and long time stability. Experimental investigations and density functional theory calculation results verify that, besides the hierarchical porous structure, large specific surface area and abundant catalytic active sites, the adjacent Ni-Nx atomic sites can modulate the d-band center of Fe-Nx single atomic active centers and balance the adsorption–desorption affinities to O2 molecules and oxygen-containing intermediates on Fe-Nx, thus leading to an superior ORR activity with a more positive half-wave potential (0.89 V vs. RHE) than the single Fe or Ni atomic catalyst and the commercial Pt/C catalyst. Moreover, with FeNi-DSAs-PNCH as the air cathode and zinc foil as the anode, an assembled Zn-air battery exhibits a higher open-circuit voltage of 1.48 V and a larger specific capacity of 802.18 mAh g−1 than that of the Pt/C-based Zn-air battery (1.37 V and 664.78 mAh g−1, respectively). This work develops a convenient strategy for preparing dual-metal single-atomic cataysts as promising substitutes for the commercial Pt/C catalysts in the practical energy conversion applications, and also offers experimental and theoretical guidance for rational designing and improvement of ORR and other catalysts by tailoring the d-band center of the active sites.

Continuous Flow Processes as an Enabling Tool for the Synthesis of Constrained Pseudopeptidic Macrocycles.

Herein we report our efforts to develop a continuous flow methodology for the efficient preparation of pseudopeptidic macrocyclic compounds containing the hexahydropyrrolo-[3,4-f]-isoindolocyclophane scaffold and involving four coupled substitution reactions in the macrocyclization process. Appropriate design of a supported base permitted the continuous production of the macrocycles even at large scales, taking advantage of the positive template effect promoted by the bromide anions. In addition, the use of flow protocols allowed a ca. 20-fold increase in productivity as well as reducing the environmental impact almost 2 orders of magnitude, in comparison with the related batch macrocyclization process.