scholarly journals Microwave Hydration Monitoring: System Assessment Using Fasting Volunteers

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 6949
Author(s):  
Brendon C. Besler ◽  
Elise C. Fear
Keyword(s):  
Recent Work ◽  
Gold Standard ◽  
Microwave Frequency ◽  
Hydration Status ◽  
Frequency Range ◽  
Physiological Processes ◽  
Assessment Techniques ◽  
System Assessment ◽  
Over Time ◽  
Hydration Assessment

Hydration is an important aspect of human health, as water is a critical nutrient used in many physiological processes. However, there is currently no clinical gold standard for non-invasively assessing hydration status. Recent work has suggested that permittivity in the microwave frequency range provides a physiologically meaningful metric for hydration monitoring. Using a simple time of flight technique for estimating permittivity, this study investigates microwave-based hydration assessment using a population of volunteers fasting during Ramadan. Volunteers are measured throughout the day while fasting during Ramadan and while not fasting after Ramadan. Comparing the estimated changes in permittivity to changes in weight and the time s fails to establish a clear relationship between permittivity and hydration. Assessing the subtle changes in hydration found in a population of sedentary, healthy adults proves difficult and more work is required to determine approaches suitable for tracking subtle changes in hydration over time with microwave-based hydration assessment techniques.

Novel hydration assessment techniques employing thirst and a water intake challenge in healthy men

2014 ◽  
Vol 39 (2) ◽  
pp. 138-144 ◽  
Author(s):  
Lawrence E. Armstrong ◽  
Matthew S. Ganio ◽  
Jennifer F. Klau ◽  
Evan C. Johnson ◽  
Douglas J. Casa ◽  
...  
Keyword(s):  
Body Mass ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Fluid Replacement ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Healthy Men ◽  
Hydration State ◽  
Assessment Techniques ◽  
Hydration Assessment

Exploring novel hydration indices is important because no human biomarker has been shown to be incontrovertibly valid in all life situations. The present investigation was designed to identify inexpensive, nontechnical methods to use when self-assessing hydration status. This investigation evaluated the validity and efficacy of 2 novel techniques (i.e., thirst sensation and urine volume) to assess hydration state of 29 active men (mean ± SD; age, 23 ± 4 years; body mass, 76.02 ± 11.94 kg) at rest. Eight combinations of 4 water challenges (4.8, 9.3, 11.0, or 14 mL·kg−1) and 2 hydration states (mildly hypohydrated (HY), –2.0%; euhydrated (EU), –0.2% body mass) were employed. First, thirst was linearly related to body water loss, and ratings of thirst distinguished HY from EU (p < 0.001) subsequent to 19 h of controlled food and fluid intake. Second, measurements of urine volume 60 min after consuming a water bolus (11.0 or 14 mL·kg−1) were strongly and inversely correlated with entering hydration state, assessed by urine specific gravity (r2 = 0.76, p < 0.0001) and urine osmolality (r2 = 0.77, p < 0.0001). We concluded that healthy men can employ simple measurements of morning thirst sensation and urine volume to identify the presence of mild hypohydration and to guide fluid replacement. These 2 techniques are relevant because HY (–2% body mass) is the approximate threshold for the onset of thirst, reduced endurance exercise performance, and decrements of working memory and mood.

EBG at microwave frequency range: Bragg and/or resonant effect?

2004 ◽  
Vol 42 (5) ◽  
pp. 383-385 ◽  
Author(s):  
Asier Ibáñez Loinaz ◽  
Carlos del Río Bocio
Keyword(s):  
Microwave Frequency ◽  
Frequency Range ◽  
Resonant Effect

Long-Run Effects in Dynamic Systems: New Tools for Cross-Lagged Panel Models

2021 ◽  
pp. 109442812199322
Author(s):  
Ali Shamsollahi ◽  
Michael J. Zyphur ◽  
Ozlem Ozkok
Keyword(s):  
Recent Work ◽  
Dynamic Systems ◽  
Quantitative Methods ◽  
Simulated Dataset ◽  
Impulse Responses ◽  
Panel Models ◽  
Long Run ◽  
Short Run ◽  
User Friendly ◽  
Over Time

Cross-lagged panel models (CLPMs) are common, but their applications often focus on “short-run” effects among temporally proximal observations. This addresses questions about how dynamic systems may immediately respond to interventions, but fails to show how systems evolve over longer timeframes. We explore three types of “long-run” effects in dynamic systems that extend recent work on “impulse responses,” which reflect potential long-run effects of one-time interventions. Going beyond these, we first treat evaluations of system (in)stability by testing for “permanent effects,” which are important because in unstable systems even a one-time intervention may have enduring effects. Second, we explore classic econometric long-run effects that show how dynamic systems may respond to interventions that are sustained over time. Third, we treat “accumulated responses” to model how systems may respond to repeated interventions over time. We illustrate tests of each long-run effect in a simulated dataset and we provide all materials online including user-friendly R code that automates estimating, testing, reporting, and plotting all effects (see https://doi.org/10.26188/13506861 ). We conclude by emphasizing the value of aligning specific longitudinal hypotheses with quantitative methods.

scholarly journals Historical Disparities and Gendered Citation Patterns

2018 ◽  
Vol 26 (3) ◽  
pp. 338-344 ◽  
Author(s):  
David A. M. Peterson
Keyword(s):  
Social Science ◽  
Political Science ◽  
Recent Work ◽  
Citation Data ◽  
Science Methodology ◽  
Social Science Methodology ◽  
Over Time

In this comment on Dion, Sumner, and Mitchell’s article “Gendered Citation Patterns across Political Science and Social Science Methodology Fields,” I explore the role of changes in the disparities of citations to work written by women over time. Breaking down their citation data by era, I find that some of the patterns in citations are the result of the legacy of disparity in the field. Citations to more recent work come closer to matching the distribution of the gender of authors of published work. Although the need for more equitable practices of citation remains, the overall patterns are not quite as bad as Dion, Sumner, and Mitchell conclude.

Topical carbonic anhydrase inhibitors and glaucoma in 2021: where do we stand?

2021 ◽  
pp. bjophthalmol-2021-319530
Author(s):  
Ari Stoner ◽  
Alon Harris ◽  
Francesco Oddone ◽  
Aditya Belamkar ◽  
Alice Chandra Verticchio Vercellin ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Gold Standard ◽  
Aqueous Humour ◽  
Beta Blockers ◽  
Combination Therapies ◽  
Potential Influence ◽  
Carbonic Anhydrase Inhibitors ◽  
Current State ◽  
Prescribing Trends ◽  
Over Time

Carbonic anhydrase inhibitors (CAIs) have been used for many decades in the treatment of glaucoma. Systemic CAIs were an early treatment option to lower intraocular pressure by reducing aqueous humour production; however, frequent side effects including polyuria and paresthesia contributed to the eventual development of topical CAIs. As topical drug development evolved over time, prostaglandin analogues and beta-blockers have become the gold standard of glaucoma therapies. Although prescribed less often than other classes of topical glaucoma therapies, topical CAIs continue to be used in combination therapies with beta-blockers and alpha agonists. Topical CAIs have also been demonstrated to alter biomarkers of ocular haemodynamics, which have relevance in glaucoma. The purpose of this review is to review and summarise the current state of topical CAI prescribing trends, known efficacy and suggested mechanisms and potential influence on ocular haemodynamics for the future of glaucoma management.

Conclusion

2019 ◽  
pp. 177-196
Author(s):  
Timothy Alborn
Keyword(s):  
British Empire ◽  
Gold Standard ◽  
Gold Rush ◽  
Short Term ◽  
British Economy ◽  
Over Time

The discovery of gold in California in 1848, and in Australia three years later, transformed the landscape for most of the themes discussed in the book. By doubling the world’s supply of gold in less than a decade, these discoveries produced short-term inflation and, over time, made it possible for other nations to join Britain on the gold standard—both of which processes radically altered the financial significance of gold in the British economy. By newly identifying the extraction of gold with the British Empire, the Australian gold rush rendered it more difficult for British observers to domesticate the metal. The huge influx of new gold supplies also threatened to wreak havoc on the conviction that gold was perennially precious. Although it would soon regain its prior value, the misgivings that surfaced in the 1850s remind us that gold’s value was always contingent.

Microwave Photoconductivity Measurements to Characterize Semiconductors

1990 ◽  
Vol 189 ◽  
Author(s):  
M. Kunst
Keyword(s):  
Semiconductor Devices ◽  
Microwave Frequency ◽  
Frequency Range ◽  
General Survey ◽  
Characterization Techniques ◽  
Transient Photoconductivity

ABSTRACTAfter a general survey of characterization techniques the use of transient photoconductivity measurements in the microwave frequency range for the characterization of semiconductors and semiconductor devices for (opto)electronic applications is treated. Experimental details and applications of these measurements are given.

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