scholarly journals A Prototype System for Measuring Microwave Frequency Reflections from the Breast

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
J. Bourqui ◽  
J. M. Sill ◽  
E. C. Fear
Keyword(s):  
Breast Imaging ◽  
Microwave Frequency ◽  
Initial Study ◽  
Microwave Imaging ◽  
Microwave Measurement ◽  
Prototype System ◽  
Measurement Sensitivity ◽  
System Sensitivity ◽  
Work Related ◽  
Insight Into

Microwave imaging of the breast is of interest for monitoring breast health, and approaches to active microwave imaging include tomography and radar-based methods. While the literature contains a growing body of work related to microwave breast imaging, there are only a few prototype systems that have been used to collect data from humans. In this paper, a prototype system for monostatic radar-based imaging that has been used in an initial study measuring reflections from volunteers is discussed. The performance of the system is explored by examining the mechanical positioning of sensor, as well as microwave measurement sensitivity. To gain insight into the measurement of reflected signals, simulations and measurements of a simple phantom are compared and discussed in relation to system sensitivity. Finally, a successful scan of a volunteer is described.

scholarly journals Measurement and Analysis of Microwave Frequency Signals Transmitted through the Breast

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Jeremie Bourqui ◽  
John Garrett ◽  
Elise Fear
Keyword(s):  
Breast Imaging ◽  
Microwave Frequency ◽  
Left Breast ◽  
Reliable Measurement ◽  
Immersion Medium ◽  
Measurement And Analysis ◽  
Microwave Signals ◽  
The Right ◽  
Breast Tissues ◽  
Insight Into

Microwave approaches to breast imaging include the measurement of signals transmitted through and reflected from the breast. Prototype systems typically feature sensors separated from the breast, resulting in measurements that include the effects of the environment and system. To gain insight into transmission of microwave signals through the breast, a system that places sensors in direct contact with the breast is proposed. The system also includes a lossy immersion medium that enables measurement of the signal passing through the breast while significantly attenuating signals traveling along other paths. Collecting measurements at different separations between sensors also provides the opportunity to estimate the average electrical properties of the breast tissues. After validation through simulations and measurements, a study of 10 volunteers was performed. Results indicate symmetry between the right and left breast and demonstrate differences in attenuation, maximum frequency for reliable measurement, and average properties that likely relate to variations in breast composition.

Abstract WP82: Transcranial Doppler Detection of Microembolic Signals During the Advancement and Deployment of Pipeline Embolization Devices in Unruptured Intracranial Aneurysm Repair

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Andres Hughes ◽  
Mark J Dannenbaum ◽  
Peng R Chen ◽  
Arthur L Day ◽  
Huimahn A Choi ◽  
...  
Keyword(s):  
Transcranial Doppler ◽  
Neurological Complication ◽  
Initial Study ◽  
Relative Safety ◽  
High Incidence ◽  
Device Placement ◽  
The Mean ◽  
Aneurysm Repair ◽  
Very High ◽  
Insight Into

Introduction: Pipeline embolization devices (PED) have become an essential tool in the endovascular treatment of complex intracranial aneurysms. A high-density stent like device, the PED functions to redirect blood flow and facilitate the growth and remodeling of the artery. Postoperative ischemic stroke proves to be the most common neurological complication associated with treatment, ranging from about 3-6% with most occurring within 30 days. Transcranial Doppler (TCD) monitoring has been used in the past to evaluate similar procedures by measuring the occurrence of microembolic signals (MES). Due to the delivery and manipulation of the PED and its thrombotic nature, microembolic events have been postulated to form during device placement and contribute to thromboembolism. Our initial study is the first to detect and measure MES during a PED procedure. Methods: Patients undergoing endovascular PED treatment were simultaneously monitored with TCD. MES were detected, separated from artifacts, and counted for each step. Results: Embolic signals were detected in all patients and were highest during deployment. With 3 PED deployments in the paraophthalmic ICA of 2 patients, the mean MES during PED deployment was 515 +/- 46. Average emboli per second during deployment was 1.62 +/- 0.59 verses 0.30 +/- 0.12 emboli per second observed prior to microcatheter insertion and manipulation. Conclusion: A very high incidence of MES was observed during the procedure and PED deployment. The little success thus far in elucidating a possible mechanism to account for PED’s associated complications warrants more investigation. Determining the occurrence of MES might reveal insight into the relative safety of each step and on the formation of distal thromboembolisms.

scholarly journals Reference Breast Phantoms for Low-Cost Microwave Imaging

2020 ◽  
Vol 14 (4) ◽  
pp. 411-415
Author(s):  
Emine Avşar Aydin ◽  
Selin Yabaci Karaoğlan
Keyword(s):  
Breast Cancer ◽  
Low Cost ◽  
Microwave Frequency ◽  
Biological Tissues ◽  
Microwave Imaging ◽  
Vector Network Analyzers ◽  
Network Analyzers ◽  
Computer Based ◽  
Breast Phantoms ◽  
Inverse Radon Transform

Microwave imaging provides an alternative method for breast cancer screening and the diagnosis of cerebrovascular accidents. Before a surgical operation, the performance of microwave imaging systems should be evaluated on anatomically detailed anthropomorphic phantoms. This paper puts forward the advances in the development of breast phantoms based on 3D printing structures filled with liquid solutions that mimic biological tissues in terms of complex permittivity in a wide microwave frequency band. In this paper; four different experimental scenarios were created, and measurements were performed, and although there are many vector network analyzers on the market, the miniVNA used in this study has been shown to have potential in many biomedical applications such as portable computer-based breast cancer detection studies. We especially investigated the reproducibility of a particular mixture and the ability of some mixes to mimic various breast tissues. Afterwards, the images similar to the experimentally created scenarios were obtained by implementing the inverse radon transform to the obtained data.

scholarly journals Microwave Transmittance Technique Using Microstrip Patch Antennas, as a Non-Invasive Tool to Determine Soil Moisture in Rhizoboxes

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1166
Author(s):  
Paulo Sergio de Paula Herrmann ◽  
Viktor Sydoruk ◽  
Felipe Nieves Marques Porto
Keyword(s):  
Soil Moisture ◽  
Plant Root ◽  
Microwave Frequency ◽  
Patch Antennas ◽  
System Sensitivity ◽  
Non Invasive ◽  
Microstrip Patch Antennas ◽  
Microstrip Patch ◽  
Quantitative Results ◽  
Plant Root Systems

Investigating the growth behavior of plant root systems as a function of soil water is considered an important information for the study of root physiology. A non-invasive tool based on electromagnetic wave transmittance in the microwave frequency range, operating close to 4.8 GHz, was developed using microstrip patch antennas to determine the volumetric moisture of soil in rhizoboxes. Antennas were placed on both sides of the rhizobox and, using a vector network analyzer, measured the S parameters. The dispersion parameter S21 (dB) was also used to show the effect of different soil types and temperature on the measurement. In addition, system sensitivity, reproducibility and repeatability were evaluated. The quantitative results of the soil moisture, measured in rhizoboxes, presented in this paper, demonstrate that the microwave technique using microstrip patch antennas is a reliable, non-invasive and accurate system, and has shown potentially promising applications for measurement of rhizobox-based root phenotyping.

scholarly journals Understanding adults’ strong problem-solving skills based on PIAAC

2017 ◽  
Vol 29 (7/8) ◽  
pp. 537-553 ◽  
Author(s):  
Raija Hämäläinen ◽  
Bram De Wever ◽  
Kari Nissinen ◽  
Sebastiano Cincinnato
Keyword(s):  
Problem Solving ◽  
Everyday Life ◽  
Continuous Process ◽  
Vocational Education And Training ◽  
Problem Solving Skills ◽  
Content Type ◽  
Work Related ◽  
Problem Solvers ◽  
Insight Into ◽  
Good Problem

Purpose Research has shown that the problem-solving skills of adults with a vocational education and training (VET) background in technology-rich environments (TREs) are often inadequate. However, some adults with a VET background do have sound problem-solving skills. The present study aims to provide insight into the socio-demographic, work-related and everyday life factors that are associated with a strong problem-solving performance. Design/methodology/approach The study builds on large-scale data of the Programme for the International Assessment of Adult Competencies (PIAAC) and gives insight into VET adults (N = 12,929) with strong problem-solving skills in 11 European countries. Findings This study introduces new knowledge with respect to the socio-demographic, work-related and everyday life background factors that contribute to successful VET adults’ problem-solving skills. The findings of the authors illustrate that a continuous process of development including non-formal and informal activity, as well as learning taking place at work, is associated with strong performance in problem-solving skills in TRE. Research limitations/implications An important implication of this study is that this paper introduces novel knowledge for VET adults’ competences and can be used to support the development of VET adults’ problem-solving skills in TREs. Originality/value The study was conducted to explore new understanding about good problem-solvers in TREs with a VET background. The originality of the study derives from its focus on good problem-solvers in TREs related to a VET background. The findings can be used to create novel ways to enhance the development of VET adults’ problem-solving skills in TREs.

scholarly journals A Fractional Ramp Generator with Improved Linearity and Phase-Noise Performance for the Use in Heterodyne Measurement Systems

2005 ◽  
Vol 3 ◽  
pp. 75-81
Author(s):  
T. Musch ◽  
B. Schiek
Keyword(s):  
Phase Noise ◽  
Prototype System ◽  
Abstract Concepts ◽  
Measurement Sensitivity ◽  
Ramp Generator ◽  
Basic Measurement ◽  
Phase Noise Performance ◽  
Linearity Error ◽  
Set Up ◽  
Frequency Detector

Abstract. Concepts for the generation and the measurement of highly linear frequency ramps are presented. The fractional ramp synthesiser concept shown here is able to generate frequency ramps with a very low phase noise level, a very good frequency linearity and reproducibility. Related to the bandwidth of the generated frequency ramps of 4.5 GHz a relative linearity error below 4·10–10 is demonstrated in a prototype system. This linearity error is close to the limit set by the phase noise floor of the ramp generators and marks a significant improvement over existing aproaches (Musch and Schiek, 2000). The basic measurement sensitivity due to the phase noise is 1.8·10–10 without averaging. As the phase noise is important for the linearity of the frequency ramp the set-up has to be optimised for a good phase noise behaviour, too. In order to achieve this good phase noise a special phase-frequency detector is introduced that is especially designed for the use in a fractional phase locked loop.

scholarly journals Mind the gap: identifying barriers to students engaging in creative practices in higher education

2020 ◽  
Vol 12 (2) ◽  
pp. 207-220
Author(s):  
Lluís Solé ◽  
Laia Sole-Coromina ◽  
Simon Ellis Poole
Keyword(s):  
Higher Education ◽  
Design Methodology ◽  
Methodological Approach ◽  
Initial Study ◽  
Faculty Members ◽  
Intercultural Understanding ◽  
Content Type ◽  
Creative Processes ◽  
Insight Into

PurposeCreativity is nowadays seen as a desirable goal in higher education. In artistic disciplines, creative processes are frequently employed to assess or evaluate different students' skills. The purpose of this study is to identify potential pitfalls for students involved in artistic practices in which being creative is essential.Design/methodology/approachThree focus groups involving Education Faculty members from different artistic disciplines allowed for the identification of several constraints when creativity was invoked. This initial study used a quantitative approach and took place in the “Universitat de Vic” (Catalonia, Spain).FindingsFindings suggest a correlation with existing literature and simultaneously point at some nuances that require consideration: emerging aspects embedded in creative processes that may help decrease some limiting effects that being creative can generate.Research limitations/implicationsThe main limitations of this research derive from the very nature of the methodological approach. Focus group has been the single used source. Other means of collecting data, such as the analysis of programs, could be used in the future.Originality/valueThis case study, while culturally specific, offers a useful insight into the potential of further work in non-artistic disciplines but crucially across disciplines. It has tremendous value for the development of intercultural understanding in the higher education sector, specifically in terms of assessment.

A Novel Wafer-Level Double Side Packaging and Its Microwave Performance

2012 ◽  
Vol 2012 (1) ◽  
pp. 000040-000045
Author(s):  
Xiao Chen ◽  
Jiajie Tang ◽  
Gaowei Xu ◽  
Le Luo
Keyword(s):  
Transmission Loss ◽  
Microwave Frequency ◽  
High Resistivity ◽  
Microwave Measurement ◽  
Wafer Level ◽  
High Frequency Signal ◽  
Packaging Structure ◽  
Low Permittivity ◽  
High Resistivity Silicon ◽  
Dielectric Polymer

In this paper, a wafer-level System-in-Packaging structure using through silicon via (TSV) for integration on both sides of the silicon wafer is presented. It is composed of BCB/ metal multilayers, high-resistivity silicon substrate with TSV. To reduce the transmission loss in microwave frequency, not only the high-resistivity silicon is used, but also a special TSV structure with 6 grounded shielding vias around the core via are adopted. Microstrip line (MSL) is used to transmit high-frequency signal on package plane together with the low permittivity intermediate dielectric polymer, BCB. Descriptions on the interconnection structure and the fabrication process are included. The microwave measurement result of the MSL connected by TSVs is measured up to 35GHz. The results of both the simulation and the measurement are presented.

Sign in / Sign up

Export Citation Format

Share Document