Dual-Channel Probe of Carbon Dots Cooperating with Lanthanide Complex Employed for Simultaneously Distinguishing and Sequentially Detecting Tetracycline and Oxytetracycline

Tetracycline (TC) and oxytetracycline (OTC) are the most widely used broad-spectrum antimicrobial agents in tetracycline drugs, and their structures and properties are very similar, so it is a great challenge to distinguish and detect these two antibiotics with a single probe at the same time. Herein, a dual-channel fluorescence probe (SiCDs@mMIPs-cit-Eu) was developed by integrating two independent reaction sites with SiCDs-doped mesoporous silica molecular imprinting group and europium complex group into a nanomaterial. The synergistic influence of inner filter effect and “antenna effect” can be guaranteed to solve the distinction between TC and OTC. Moreover, this novel strategy can also sequentially detect TC and OTC in buffer solution and real samples with high sensitivity and selectivity. This method revealed good responses to TC and OTC ranging from 0 to 5.5 μM with a detection limit of 5 and 16 nM, respectively. Combined with the smartphone color-scanning application, the portable and cheap paper-based sensor was designed to realize the multi-color visual on-site detection of TC and OTC. In addition, the logic gate device was constructed according to the fluorescence color change of the probe for TC and OTC, which provided the application possibility for the intelligent detection of the probe.

Gradient coil and radiofrequency induced heating of orthopaedic implants in MRI: influencing factors

Patients with implanted orthopaedic devices represent a growing number of subjects undergoing magnetic resonance imaging (MRI) scans each year. MRI safety labelling is required for all implants under the EU Medical Device Regulations to ensure regulatory compliance, with each device assessed through standardised testing procedures. In this paper, we employ parametric studies to assess a range of clinically relevant factors that cause tissue heating, performing simulations with both radiofrequency (RF) and gradient coil (GC) switching fields, the latter of which is often overlooked in the literature. A series of worst case scenarios for both types of excitation field are discussed. In the case of GC fields large volume implants and large plate areas with the field oriented perpendicular to the plane cause the highest heating levels, along with sequences with high rates of field switching. Implant heating from RF fields is driven primarily from the antenna effect, with thin, linear implants of resonant length resulting in the highest temperature rises. In this work, we show that simplifications may be made to the field sequence and device geometry without significantly comprising the accuracy of the simulation results, opening up the possibility for generic estimates of the implant heating for orthopaedic device manufacturers and opportunities to simplify the safety compliance process.

Theoretical Study of 8-hydroxyquinoline Derivatives as Potential Antennas in Lanthanide complexes: Photophysical Properties and Elucidation of Energy Transfer Pathways.

A series of 8-hydroxyquinoline derivatives were characterized and tested as potential antennas in a set of designed lanthanide complexes. The molecular structure and ligand localized nature of the excited states were studied in the framework of the multiconfigurational methods CASSCF/NEVPT2 combined with TDDFT- based approaches, which allows applying a fragmentation scheme in the analysis of the most probable sensitization pathway via antenna effect. The photophysical properties of all the complexes and antennas were carefully analyzed, and the most probable energy transfer pathways were elucidated. Rate constants for photophysical processes involved in the mechanism were calculated, showing a significant contribution of the vibronic coupling in all cases and the predominant intersystem-crossing between S1 and T1 states was demonstrated from the analysis of the nature of the wave function of those states. The energy transfer process described herein demonstrates the possibility of Eu(III) and Nd(III) sensitization by the studied ligands. The proposed methodology gives a complete picture of the antenna excited state dynamics.

Enhancement of the Luminescence Properties of Eu (III) Containing Paramagnetic Saponite Clays

In this study, 1,10-phenanthroline molecules were introduced in the interlayer space of a paramagnetic synthetic saponite clay containing both Eu3+ and Gd3+ ions in structural positions. Two samples with different loading of phenanthroline dye were prepared. The resulting hybrid materials possessed improved optical emission properties due to an efficient antenna effect from the phenanthroline to the Eu3+ centers; this effect was demonstrated to be higher than the metal-to-metal Gd3+-Eu3+ energy transfer previously studied. Insights on the relaxometric properties in aqueous solution of the solids after incorporation of the antenna groups were also obtained through NMR relaxometric analyses.

Photophysical Challenges and Antenna Effect Between Click Reaction-based Bodipy Derivatives Manufactured From Knorr Pyrrole

In this paper, a series of click reaction-based Bodipy derivatives have been synthesized as part of a preliminary study. Following the characterization of the four challenger molecules, the photophysical properties (absorption, emission, excitation, molar absorption coefficient, quantum yield, etc.) were examined in various organic solvents. The results showed that the energy transfer from the Bodipy cores to other moieties was calculated between 71% and 93% depending on different π-electron configurations and chromophore groups.

Research on Electromagnetic-Radiated Emission of Multi-in-One Electric Drive System

The strong electromagnetic interference produced by the electric drive system is the main factor that leads to the strong radiated emission of electric vehicles. It is very important to study the influence of the electric drive system on vehicle-radiated emission by taking the common-mode current of the electric drive system as the interference source. In this paper, the conducted emission model of the electric drive system is proposed, and the common-mode current is calculated by this model. The influence of filter on the common-mode interference current of HVDC cables is calculated and analyzed, and then the radiating antenna effect model of HVDC cables is established. Based on this, a vehicle-level radiated emission simulation model including an electric drive system and DC cables was established. The effectiveness of the conducted emission model was verified by experiments. The effects of different shielding structures on the shielding efficiency of HVDC cables were compared. Quantitative guidance for EMI suppression design of multi-in-one electric drive system design can be provided by the model in this paper.