DNA nanotechnology offers a versatile toolbox for precise spatial and temporal manipulation of matter on the nanoscale. However, rendering DNA‐based systems responsive to light has remained ...challenging. Herein, we describe the remote manipulation of native (non‐photoresponsive) chiral plasmonic molecules (CPMs) using light. Our strategy is based on the use of a photoresponsive medium comprising a merocyanine‐based photoacid. Upon exposure to visible light, the medium decreases its pH, inducing the formation of DNA triplex links, leading to a spatial reconfiguration of the CPMs. The process can be reversed simply by turning the light off and it can be repeated for multiple cycles. The degree of the overall chirality change in an ensemble of CPMs depends on the CPM fraction undergoing reconfiguration, which, remarkably, depends on and can be tuned by the intensity of incident light. Such a dynamic, remotely controlled system could aid in further advancing DNA‐based devices and nanomaterials.
The spatial configuration and optical properties of non‐photoresponsive DNA‐origami‐based plasmonic assemblies can be controlled with light using a photoresponsive medium. Upon exposure to visible light, the medium's pH decreases, inducing the formation of DNA triplex links in the plasmonic assemblies, leading to their spatial reconfiguration, which can be reversed by turning the light off.
Hierarchical self-assembly of nanostructures with addressable complexity has been a promising route for realizing novel functional materials. Traditionally, the fabrication of such structures on a ...large scale has been achievable using top-down methods but with the cost of complexity of the fabrication equipment
versus
resolution and limitation mainly to 2D structures. More recently bottom-up methods using molecules like DNA have gained attention due to the advantages of low fabrication costs, high resolution and simplicity in an extension of the methods to the third dimension. One of the more promising bottom-up techniques is DNA origami due to the robust self-assembly of arbitrarily shaped nanostructures with feature sizes down to a few nanometers. Here, we show that under specific ionic conditions of the buffer, the employed plus-shaped, blunt-ended Seeman tile (ST) origami forms elongated, ordered 2D lattices, which are further rolled into 3D tubes in solution. Imaging structures on a surface by atomic force microscopy reveals ribbon-like structures, with single or double layers of the origami lattice. Further studies of the double-layered structures in a liquid state by confocal microscopy and cryo-TEM revealed elongated tube structures with a relatively uniform width but with a varying length. Through meticulous study, we concluded that the assembly process of these 3D DNA origami tubes is heavily dependent on the concentration of both mono- and divalent cations. In particular, nickel seems to act as a trigger for the formation of the tubular assemblies in liquid.
By tuning the ionic conditions, plus-shaped, blunt-ended DNA-origami lattices are driven to self-assemble elongated, ordered structures: adding Ni
2+
triggers the formation of ribbon-shaped 2D-lattices, which roll into 3D-tubes at higher Ni
2+
concentrations.
DNA nanotechnology offers a versatile toolbox for precise spatial and temporal manipulation of matter on the nanoscale. However, rendering DNA‐based systems responsive to light has remained ...challenging. Herein, we describe the remote manipulation of native (non‐photoresponsive) chiral plasmonic molecules (CPMs) using light. Our strategy is based on the use of a photoresponsive medium comprising a merocyanine‐based photoacid. Upon exposure to visible light, the medium decreases its pH, inducing the formation of DNA triplex links, leading to a spatial reconfiguration of the CPMs. The process can be reversed simply by turning the light off and it can be repeated for multiple cycles. The degree of the overall chirality change in an ensemble of CPMs depends on the CPM fraction undergoing reconfiguration, which, remarkably, depends on and can be tuned by the intensity of incident light. Such a dynamic, remotely controlled system could aid in further advancing DNA‐based devices and nanomaterials.
The spatial configuration and optical properties of non‐photoresponsive DNA‐origami‐based plasmonic assemblies can be controlled with light using a photoresponsive medium. Upon exposure to visible light, the medium's pH decreases, inducing the formation of DNA triplex links in the plasmonic assemblies, leading to their spatial reconfiguration, which can be reversed by turning the light off.
Condition and cloud based prognostics offers the opportunities to reduce loss due to machine failures and delay in planning for maintenance activities and spare parts. The time complexity of the ...prognostics algorithms used for predicting imminent component failures or the remaining useful life of critical components plays a vital role in determining the accuracy and feasibility of prognostics systems. We discuss the infrastructure needs of cloud based prognostics and compare time complexity of different prognostics methods used to predict machine failures.
The efficacy of pit and fissure sealants in preventing occlusal caries is a well-established fact. Considering the difficulty in achieving strict isolation for a longer duration while treating the ...pediatric patients, a simplified procedure of sealant application is desirable. While, a self-etching sealant, Prevent Seal offers a quick procedure, the physical properties of this material haven't been studied yet. Thus, this study was aimed to comparatively evaluate sealing ability, penetration and adaptation of a self-etching pit and fissure sealant and a conventional resin sealant.
This was an
intergroup comparative study, which consisted of 2 groups- Group I (Conventional acid etch sealant, Clinpro) and Group II (Self etching sealant, Prevent Seal). Out of 32 selected teeth 16 were used to study microleakage, with the help of dye penetration test using Övrebö and Raadal criteria. Remaining 16 were used to evaluate sealant penetration and adaptation viz bubbles in the bottom of fissure, debris in the fissure, tags in the bottom of the fissure and tags at cuspal slopes and fissure entrance was done using stereomicroscope. Post stereomicroscopic evaluation 4 samples each were randomly chosen from both the groups and checked for etching pattern using Scanning electronic microscope.
The comparison of tested properties between the groups was done using Chi square test. There was no statistically significant difference observed when microleakage and sealant penetration / adaptation properties were compared between two groups (
=0.63 and
= 0.131, 0.131, 0.302, 0.106 respectively). No conclusive results could be withdrawn while etching patterns were compared between the groups (
=0.717).
The self-etching sealant Prevent seal was found to have similar microleakage, sealant penetration and adaptation properties as conventional acid etch sealant.
Pit and fissure sealant, self-etching, scanning electron microscope, sealing ability.
This paper proposes a subcarrier and power allocation (SPA) scheme to reduce the multi-access interference (MAI) in multirate MC-CDMA systems. Assuming complete knowledge of the channel, SPA ...algorithm is developed to enhance the power efficiency and bit error rate (BER). In SPA, the entire bandwidth is divided into nonoverlapping sets each having equal number of subcarriers. Each user's data is spread over one or more sets of subcarriers based on the corresponding channel response, so that SPA transmits a user's data only over those subcarriers that perform well for the user during a given transmission period. Simulation results show that SPA leads MC-CDMA to have better bit error rates and power efficiency.
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