The pitfalls of in vivo imaging techniques Petruzzellis, Francesco; Pagliarani, Chiara; Savi, Tadeja ...
New phytologist,
October 2018, Letnik:
220, Številka:
1
Journal Article
Recenzirano
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Synchrotron X-ray computed micro-tomography (microCT) has emerged as a promising noninvasive technique for in vivo monitoring of xylem function, including embolism build-up under drought and ...hydraulic recovery following re-irrigation. Yet, the possible harmful effects of ionizing radiation on plant tissues have never been quantified.
We specifically investigated the eventual damage suffered by stem living cells of three different species exposed to repeated microCT scans. Stem samples exposed to one, two or three scans were used to measure cell membrane and RNA integrity, and compared to controls never exposed to X-rays.
Samples exposed to microCT scans suffered serious alterations to cell membranes, as revealed by marked increase in relative electrolyte leakage, and also underwent severe damage to RNA integrity. The negative effects of X-rays were apparent in all species tested, but the magnitude of damage and the minimum number of scans inducing negative effects were species-specific.
Our data show that multiple microCT scans lead to disruption of fundamental cellular functions and processes. Hence, microCT investigation of phenomena that depend on physiological activity of living cells may produce erroneous results and lead to incorrect conclusions.
Vulnerability curves (VCs) are a useful tool to investigate the susceptibility of plants to drought-induced hydraulic failure, and several experimental techniques have been used for their ...measurement. The validity of the bench dehydration method coupled to hydraulic measurements, considered as a 'golden standard', has been recently questioned calling for its validation with non-destructive methods. We compared the VCs of a herbaceous crop plant (Helianthus annuus) obtained during whole-plant dehydration followed by i) hydraulic flow measurements in stem segments (classical destructive method) or by ii) in vivo micro-CT observations of stem xylem conduits in intact plants. The interpolated P50 values (xylem water potential inducing 50% loss of hydraulic conductance) were −1.74 MPa and −0.87 MPa for the hydraulic and the micro-CT VC, respectively. Interpolated P20 values were similar, while P50 and P80 were significantly different, as evidenced by non-overlapping 95% confidence intervals. Our results did not support the tension-cutting artefact, as no overestimation of vulnerability was observed when comparing the hydraulic VC to that obtained with in vivo imaging. After one scan, 25% of plants showed signs of x-ray induced damage, while three successive scans caused the formation of a circular brownish scar in all tested plants. Our results support the validity of hydraulic measurements of samples excised under tension provided standard sampling and handling protocols are followed, but also show that caution is needed when investigating vital plant processes with x-ray imaging.
•Vulnerability curves (VCs) assess plants vulnerability to drought-induced embolism.•The validity and reliability of the classic hydraulic method has been questioned.•VCs of a herbaceous plant measured with hydraulic and micro-CT methods were compared.•Discrepancies between the two techniques were highlighted.•Signs of x-ray induced damage were observed on plants stem.
Accurate predictions of species distribution under current and future climate conditions require modeling efforts based on clear mechanistic relationships between climate variables and plant ...physiological functions. Vulnerability of leaves to xylem embolism is a key mechanistic trait that might be included in these modeling efforts. Here, we propose a simple set-up to measure leaf vulnerability to embolism on the basis of the optical method using a smartphone, a light source, and a notebook. Our data show that this proposed set-up can adequately quantify the vulnerability to xylem embolism of leaf major veins in
and
, producing values consistent with those obtained in temperate tree species with other methods, allowing virtually any laboratory to quantify species-specific drought tolerance on the basis of a sound mechanistic trait.
The present study considers underground passengers and investigates the ways in which they spend their time during a trip of average length or shorter. Using a structured procedure that had been ...refined after a preliminary study, more than 1,700 passengers were observed in London. The results showed that even when the length of travel is very short (2–6 stops), underground passengers engage in several occupations, especially those involving the use of mobile Information and Communication Technologies. These occupations depend on the specific spatial and temporal conditions of the travel, as well as on gender and age. These results should be useful in designing travel services that enhance passengers’ experiences; they also suggest a criterion for comparing trips using different transportation modes (i.e., looking at the time point during the trip at which the ratio of active versus passive occupations changes).
This paper describes research to investigate the attitudinal and motivational factors that might facilitate or inhibit the uptake and use of cognitive training (CT) applications via interactive ...television (iTV) by both young and older people and to explore the profiles of potential users of such applications. A questionnaire was designed and distributed as part of the Vital Mind (VM) project. Data from a sample of 848 young and older people were collected and analysed using principal component analysis (PCA) and cluster analysis (CA). PCA of 41 attitude statements identified six components/factors. Three factors measured potential drivers to uptake and use of iTV-based CT applications (‘active wellbeing’, ‘health concern’ and ‘technophilia’) and two measured potential barriers (‘unprogressiveness’ and ‘telly-negativity’). A sixth factor (‘active sociability’) could act as either a driver or barrier, depending on how socially oriented are different CT applications. CA of the factors and age data revealed seven different profiles of potential users of CT through iTV. Three of the clusters were predominantly older (labelled Cultured-Conservatives, Digital-Immigrants and Telly-Fans), three were younger (labelled Healthy-Strivers, Digital-Natives and Net-Generation) and one was middle-aged (labelled Busy-Interactors). Reported media use and activity (mental, physical and social) were consistent with the attitude profiles of the clusters. The appeal of iTV-based CT was generally high, with Digital-Natives and Digital-Immigrants indicating the most interest. This research provides evidence for the key attitudinal dimensions predictive of likely adoption and use of iTV-based CT, and a refined understanding of target younger and older user markets.
CEEDs: Unleashing the Power of the Subconscious Lessiter, Jane; Miotto, Andrea; Freeman, Jonathan ...
Procedia computer science,
2011, 2011-00-00, Letnik:
7
Journal Article, Conference Proceeding
Recenzirano
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The Collective Experience of Empathic Data Systems (CEEDs) project aims to offer a solution to the data deluge problem. With theoretical foundations in consciousness, information processing and ...creative discovery, the project proposes to develop a data analysis tool that harnesses and interprets the unconscious processes that influence our understanding of the world. Implicit reactions to immersive multimodal representations of large data sets will be used to guide a user's exploration of those data and support learning, understanding and discovery of new patterns that might otherwise be undetected using standard analysis tools.
A better image MIOTTO, Andrea
Civil engineering (New York, N.Y. 1983),
2000, 20000101, Letnik:
70, Številka:
1
Magazine Article
Remote sensing in its broadest sense refers to data gathering that does not require direct observation by a human being. Aerial data represented the first step toward reducing the degree to which ...data are gathered on the ground. Such data have helped pinpoint the most promising areas for ground-truthing, or on-site testing of geophysical phenomena. Remote sensing has also yielded highly precise elevation data and extremely high resolution site data. Digital cameras and Global Positioning System receivers are making aerial data easier to process and ever more accurate. With all the new technologies out there, engineers need to educate themselves to be sure they pick the right data for the job.
Antibiotic-resistant tuberculosis poses a global threat, causing the deaths of hundreds of thousands of people annually. While whole-genome sequencing (WGS), with its unprecedented level of detail, ...promises to play an increasingly important role in diagnosis, data analysis is a daunting challenge. Here, we present a simple-to-use web service (free for academic use at http://phyresse.org). Delineating both lineage and resistance, it provides state-of-the-art methodology to life scientists and physicians untrained in bioinformatics. It combines elaborate data processing and quality control, as befits human diagnostics, with a treasure trove of validated resistance data collected from well-characterized samples in-house and worldwide.
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