NMR micro-detectors tailored for multinuclear and electrochemistry lab-on-a-chip applications

This work offers three solutions tailored to specific applications to overcome NMR challenges in the micro-domain. As the first sub-topic of this work, different potential electrode designs, compatible with NMR technique, are suggested and experimentally evaluated. As the second focus point, this work tackles multinuclear detection challenges. In parallel, a low-cost, broadband insert is discussed to enhance the sensitivity of standard NMR coils when a small sample volume is available

Molecular Electronic Structure Calculation via a Quantum Computer

Quantum computers can be used to calculate the electronic structure and estimate the ground state energy of many-electron molecular systems. In the present study, we implement the Variational Quantum Eigensolver (VQE) algorithm, as a hybrid quantum-classical algorithm to calculate the ground state energy of the molecules such as H3+, OH-, HF and BH3 in which the number of qubits has an increasing trend. We use the parity transformation for Fermion to qubit encoding and the Unitary Coupled Cluster for Single and Double excitations (UCCSD) to construct an ansatz. We compare our quantum simulation results with the computational chemistry approaches including Full Configuration Interaction (FCI), as benchmark energy and Unrestricted Hartree-Fock (UHF), as a common computational method. Our results show that there is a good agreement between molecular ground state energy obtained from VQE and FCI. Moreover, the accuracy of the ground state energies obtained from VQE in our work is higher than the previously reported values

An NMR-compatible microfluidic platform enabling in situ electrochemistry

Combining microfluidic devices with nuclear magnetic resonance (NMR) has the potential of unlocking their vast sample handling and processing operation space for use with the powerful analytics provided by NMR. One particularly challenging class of integrated functional elements from the perspective of NMR are conductive structures. Metallic electrodes could be used for electrochemical sample interaction for example, yet they can cause severe NMR spectral and SNR degradation. These issues are more entangled at the micro-scale since the distorted volume occupies a higher ratio of the sample volume. In this study, a combination of simulation and experimental validation was used to identify an electrode geometry that, in terms of NMR spectral parameters, performs as well as for the case when no electrodes are present. By placing the metal tracks in the side-walls of a microfluidic channel, we found that NMR RF excitation performance was actually enhanced, without compromising B0 homogeneity. Monitoring in situ deposition of chitosan in the microfluidic platform is presented as a proof-of-concept demonstration of NMR characterisation of an electrochemical process

Effects of silver nanoparticle exposure on germination and early growth of Pinus sylvestris and Alnus subcordata

The possible ecological toxicity of silver nanoparticles (AgNP) was evaluated based on germination and growth characteristics of Pinus sylvestris and Alnus subcordata. Seeds were exposed to different concentrations of AgNP in soil (0, 10, 20, 40, 80 and 100 mg/kg) and aqueous suspension (0, 10 and 20 mg/L). Then, seed germination percentage (GP%), speed of germination (S.G), seedling length (SL), as well as fresh and dry weights (FW and DW) were measured. The results showed that low concentration of AgNP (under 80 mg/kg) could be used without detrimental effects on the germination characteristics of P. sylvestris in the soil. Nevertheless, inhibitory effect of AgNP was observed at 10 mg/L for P. sylvestris in aqueous suspension. The dissimilar results in soil and aqueous suspension were due to the organic matters and clay minerals in the soil. There was no significant difference (p<0.01) among the treatments of A. subcordata, not only in soil but also in the aqueous suspension

A non-resonant kinetic energy harvester for bioimplantable applications

A linear non-resonant kinetic energy harvester for implantable devices is presented. The design contains a metal platform with permanent magnets, two stators with three-dimensional helical coils for increased power generation, ball bearings, and a polydimethylsiloxane (PDMS) package for biocompatibility. Mechanical excitation of this device within the body due to daily activities leads to a relative motion between the platform and stators, resulting in electromagnetic induction. Initial prototypes without packaging have been fabricated and characterized on a linear shaker. Dynamic tests showed that the friction force acting on the platform is on the order of 0.6 mN. The resistance and the inductance of the coils were measured to be 2.2 and 0.4 mu H, respectively. A peak open circuit voltage of 1.05 mV was generated per stator at a platform speed of 5.8 cm/s. Further development of this device offers potential for recharging the batteries of implantable biomedical devices within the body.No sponso

Characterization of a Wireless Vacuum Sensor Prototype Based on the SAW-Pirani Principle

A prototype of a wireless vacuum microsensor combining the Pirani principle and surface acoustic waves (SAW) with extended range and sensitivity was designed, modelled, manufactured and characterised under different conditions. The main components of the prototype are a sensing SAW chip, a heating coil and an interrogation antenna. All the components were assembled on a 15 mm × 11 mm × 3 mm printed circuit board (PCB). The behaviour of the PCB was characterised under ambient conditions and in vacuum. The quality of the SAW interrogation signal, the frequency shift and the received current of the coil were measured for different configurations. Pressures between 0.9 and 100,000 Pa were detected with sensitivities between 2.8 GHz/Pa at 0.9 Pa and 1 Hz/Pa close to atmospheric pressure. This experiment allowed us to determine the optimal operating conditions of the sensor and the integration conditions inside a vacuum chamber in addition to obtaining a pressure-dependent signal