Improvement of magnetic resonance imaging using a wireless radiofrequency resonator array

In recent years, new human magnetic resonance imaging systems operating at static magnetic fields strengths of 7 Tesla or higher have become available, providing better signal sensitivity compared with lower field strengths. However, imaging human-sized objects at such high field strength and associated precession frequencies is limited due to the technical challenges associated with the wavelength effect, which substantially disturb the transmit field uniformity over the human body when conventional coils are used. Here we report a novel passive inductively-coupled radiofrequency resonator array design with a simple structure that works in conjunction with conventional coils and requires only to be tuned to the scanner’s operating frequency. We show that inductive-coupling between the resonator array and the coil improves the transmit efficiency and signal sensitivity in the targeted region. The simple structure, flexibility, and cost-efficiency make the proposed array design an attractive approach for altering the transmit field distribution specially at high field systems, where the wavelength is comparable with the tissue size.

Diatom Frustule Array for Flow-Through Enhancement of Fluorescent Signal in a Microfluidic Chip

Diatom frustules are a type of natural biomaterials that feature regular shape and intricate hierarchical micro/nano structures. They have shown excellent performance in biosensing, yet few studies have been performed on flow-through detection. In this study, diatom frustules were patterned into step-through holes and bonded with silicon substrate to form an open-ended filtration array. Then they were fixed into a microfluidic chip with a smartphone-based POCT. Human IgG and FITC-labeled goat–anti-human IgG were adopted to investigate the adsorption enhancement when analyte flowed through diatom frustules. The results indicated up to 16-fold enhancement of fluorescent signal sensitivity for the flow-through mode compared with flow-over mode, at a low concentration of 10.0 μg/mL. Moreover, the maximum flow rate reached 2.0 μL/s, which resulted in a significant decrease in the testing time in POCT. The adsorption simulation results of diatom array embedded in the microchannel shows good agreement with experimental results, which further proves the filtration enrichment effect of the diatom array. The methods put forward in this study may open a new window for the application of diatom frustules in biosensing platforms.

Penerima Gelombang ELF berbasis Op-Amp untuk Pengolahan Akuisisi Data Gempa Bumi

ABSTRAKPenelitian ini membahas mengenai penerima gelombang extremely low frequency (ELF) untuk pengolahan akuisisi data gempa bumi. Penerima ELF dirancang menggunakan operational amplifier (Op-Amp) dengan masukan takmembalik. Sinyal yang diterima oleh antena diteruskan ke penerima ELF yang terdiri dari preamplifier dan amplifier untuk proses penguatan, serta filter aktif orde 2 untuk menekan sinyal di atas frekuensi cut-off sebesar 50Hz. Karakterisasi penerima ELF dilakukan dengan mengamati perbandingan level tegangan sinyal keluaran terhadap level tegangan sinyal masukan, sensitivitas, serta bentuk sinyal keluaran dari penerima ELF dalam domain waktu. Hasil simulasi menunjukkan bahwa penerima ELF menghasilkan penguatan sebesar 60,8dB dengan sensitifitas tinggi untuk level sinyal masukan di bawah -30dB yang mampu memenuhi level sinyal untuk pengolahan akuisisi data.Kata kunci: extremely low frequency, penerima ELF, operational amplifier, filter aktif, gempa bumi ABSTRACTThis research presents extremely low frequency (ELF) receiver for earthquake data acquisition processing. The ELF receiver is designed based on non-inverting operational amplifier (Op-Amp). The signal received by the antenna is fed into ELF receiver which consists of preamplifier and amplifier for amplification, and second order active filter to suppress unwanted signal above the cut-off frequency of 50Hz. Characterization of ELF receiver is performed by observing the comparison of the level output signal to level input signal, sensitivity, and ELF receiver signal output in time domain. The simulation results show that the ELF receiver has gain of 60.8dB with high sensitivity for low level input signals below -30dB that is able to meet signal level for data acquisition processing.Keywords: extremely low frequency, ELF receiver, operational amplifier, active filter, earthquake

Vector-Boson scattering at the LHC: Unraveling the electroweak sector

Vector-boson scattering (VBS) processes probe the innermost structure of electroweak (EW) interactions in the Standard Model (SM), and provide a unique sensitivity for new physics phenomena affecting the gauge sector. In this review, we report on the salient aspects of this class of processes, both from the theory and experimental point of view. We start by discussing recent achievements relevant for their theoretical description, some of which have set important milestones in improving the precision and accuracy of the corresponding simulations. We continue by covering the development of experimental techniques aimed at detecting these rare processes and improving the signal sensitivity over large backgrounds. We then summarize the details of the most relevant VBS signatures and review the related measurements available to date, along with their comparison with SM predictions. We conclude by discussing the perspective at the upcoming Large Hadron Collider runs and at future hadron facilities.

Turbidity sensor response to seasonal and spatial variability of suspended particle composition in open clear waters –(Portuguese continental shelf)

<p>As part of AQUIMAR project (MAR2020 nº MAR-02.01.01-FEAMP-017 – AQUIMAR – Caraterização geral das áreas aquícolas para estabelecimento de culturas marinhas), intensive CTD surveys and turbidity/concentration data were collected in four cruises along the Portuguese continental shelf (30-200m depth), in 5 aquaculture areas from 2018 to 2020. In-situ calibration of the turbidity sensor (Seapoint Turbidity Meter) was done using the traditional gravimetric method of suspended sediments concentration (SSC) determination with water sampling and filtering. The obtained FTU/SSC relations resulted in correlations in the order of R<sup>2</sup>=70-80% for all considered surveys.</p><p>Measured turbidity and concentration values, were generally very low (<2 FTU and <2 mg/l) for all measuring periods, however variations of the FTU/SSC sensitivity between the different areas indicate that significant variations of suspended matter composition exist throughout the Portuguese continental shelf.</p><p>This study aims to understand the seasonal and spatial variations of the turbidity signal sensitivity to SSC. To this end, a closer look will be given to samples collected during two contrasting seasonal periods (spring and late autumn 2019), as well as to the general water column structure at the time of the sample collection. Additionally, results from X-Ray diffraction analysis performed in some of the filtered samples will be used to better understand the variations of the suspended sediment composition in open clear waters. The mineralogical signal shows a dominance of clay minerals in suspension (mean 83%) and calcite (mean 10%), reflecting the detritic and organic fraction of SSC, respectively.</p>

Attenuation of Microwaves Received From a Drone Owing to Smoke Obscuration

The objective of this study is to analyze the effect of smoke obscuration on the signal sensitivity of microwaves received from a drone. A spectrum analyzer and a directional antenna were employed for analyzing the received signal sensitivity and measuring the mean received power, both before and after the drone entered the smoke layer for one min in the fire training area. The drone operated in the range of 2.4 GHz to 2.48 GHz. It is found that the received power before entering the smoke layer is –39.3 dBm, at which signals and image data can be received. However, upon entering the smoke layer, the received power is reduced to –47 dBm, at which signals and image data cannot be received. Hence, the received power undergoes an attenuation of approximately 7.7 dBm (5.9 mW) owing to smoke obscuration, which causes communication outage. Based on this study, it can be concluded that the received power undergoes attenuation owing to smoke obscuration during fires. Furthermore, if a communication problem occurs due to microwave attenuation, it affects the drone’s operation.

Functional Imaging Using Fluorine (19F) MR Methods: Basic Concepts

Kidney-associated pathologies would greatly benefit from noninvasive and robust methods that can objectively quantify changes in renal function. In the past years there has been a growing incentive to develop new applications for fluorine (19F) MRI in biomedical research to study functional changes during disease states. 19F MRI represents an instrumental tool for the quantification of exogenous 19F substances in vivo. One of the major benefits of 19F MRI is that fluorine in its organic form is absent in eukaryotic cells. Therefore, the introduction of exogenous 19F signals in vivo will yield background-free images, thus providing highly selective detection with absolute specificity in vivo. Here we introduce the concept of 19F MRI, describe existing challenges, especially those pertaining to signal sensitivity, and give an overview of preclinical applications to illustrate the utility and applicability of this technique for measuring renal function in animal models.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.

Overview of CMOS Sensors for Future Tracking Detectors

Depleted Complementary Metal-Oxide-Semiconductor (CMOS) sensors are emerging as one of the main candidate technologies for future tracking detectors in high luminosity colliders. Their capability of integrating the sensing diode into the CMOS wafer hosting the front-end electronics allows for reduced noise and higher signal sensitivity, due to the direct collection of the sensor signal by the readout electronics. They are suitable for high radiation environments due to the possibility of applying high depletion voltage and the availability of relatively high resistivity substrates. The use of a CMOS commercial fabrication process leads to their cost reduction and allows faster construction of large area detectors. In this contribution, a general perspective of the state of the art of CMOS detectors for High Energy Physics experiments is given. The main developments carried out with regard to these devices in the framework of the CERN RD50 collaboration are summarized.