A Lenz lens is an electrically passive conductive element that, when placed in a time-varying magnetic field, acts as a magnetic flux concentrator or a magnetic lens. In the realm of nuclear magnetic resonance (NMR), Lenz lenses have been exploited as electrically passive metallic radiofrequency interposers placed between a sample and a tuned or untuned NMR detector in order to focus the [Formula: see text]-field of the detector onto a smaller sample space. Here we explore a novel embodiment of the Lenz lens, which acts as a non-resonant stripline interposer, i.
View Article and Find Full Text PDFCompartmentalized chemical reactions at the microscale are important in biotechnology, yet monitoring the molecular content at these small scales is challenging. To address this challenge, we integrate a compact, reconfigurable reaction cell featuring electrochemical functionality with high-resolution NMR spectroscopy. We demonstrate the operation of this system by monitoring the activity of enzymes immobilized in chemically distinct layers within a multi-layered chitosan hydrogel assembly.
View Article and Find Full Text PDFThe low frequency plateau in the frequency response of an untuned micro-resonator permits broadband radio-frequency reception, albeit at the expense of optimal signal-to-noise ratio for a particular nucleus. In this contribution we determine useful figures of merit for broadband micro-coils, and thereby explore the parametric design space towards acceptable simultaneous excitation and reception of a microfluidic sample over a wide frequency band ranging from C to H, i.e.
View Article and Find Full Text PDFCombining 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.
View Article and Find Full Text PDFIt has always been of considerable interest to study the nuclear magnetic resonance response of multiple nuclei simultaneously, whether these signals arise from internuclear couplings within the same molecule, or from uncoupled nuclei within sample mixtures. The literature contains numerous uncorrelated reports on techniques employed to achieve multi-nuclear NMR detection. This paper consolidates the subset of techniques in which single coil detectors are utilized, and highlights the strengths and weaknesses of each approach, at the same time pointing the way towards future developments in the field of multi-nuclear NMR.
View Article and Find Full Text PDFSome micronutrients like folate, vitamin B12, B6, and B2 are the source of coenzymes, which participate in one-carbon metabolism. Any disruption in this metabolism can interfere with DNA replication, repair and regulation of gene expression and ultimately promote the likelihood of carcinogenesis. This study aimed at investigating the relationship between the intakes of micronutrients involved in one-carbon metabolism with breast cancer (BrCa) and its subtype's odds.
View Article and Find Full Text PDFA 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.
View Article and Find Full Text PDFDifferent signaling pathways are involved in tissue protection against ischemia reperfusion (IR) injury, among them mammalian target of rapamycin (mTOR) and related pathways have been examined in many recent studies. Present study evaluated the role of mTOR in remote ischemic preconditioning (RIPC) of hippocampus. Renal ischemia was induced (3 cycles of 5min occlusion and 5min reperfusion of unilateral renal artery) 24h before global brain ischemia (20min bilateral common carotid artery occlusion).
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