DNA profiling, telomere analysis and antioxidant properties as tools for monitoring ex situ seed longevity

Background and Aims The germination test currently represents the most used method to assess seed viability in germplasm banks, despite the difficulties caused by the occurrence of seed dormancy. Furthermore, seed longevity can vary considerably across species and populations from different environments and studies related to the eco-physiological processes underlying such variations are still limited in their depth. The aim of the present work was the identification of reliable molecular markers that might help monitoring seed deterioration. Methods Dry seeds were subjected to artificial aging and collected at different time points for molecular/biochemical analyses. DNA damage was measured using the RAPD (Random Amplified Polymorphic DNA) approach while the seed antioxidant profile was obtained using both the DPPH (1,1-diphenyl, 2-picrylhydrazyl) assay and the Folin Ciocalteu reagent method. Electron Paramagnetic Resonance (EPR) provided profiles of free radicals. Quantitative RealTime-Polymerase Chain Reaction (QRT-PCR) was used to assess the expression profiles of the antioxidant genes MT2 (Type 2 Metallothionein) and SOD (Superoxide Dismutase). A modified QRT-PCR protocol was used to determine telomere length. Key Results The RAPD profiles highlighted different capacities of the two Silene species to overcome DNA damage induced by artificial aging. The antioxidant profiles of dry and rehydrated seeds revealed that the high-altitude taxon Silene acaulis was characterised by a lower antioxidant specific activity. Significant up-regulation of the MT2 and SOD genes was observed only in the rehydrated seeds of the low-altitude species. Rehydration resulted in telomere lengthening in both Silene species. Conclusions Different seed viability markers have been selected for plant species showing inherent variation of seed longevity. RAPD analysis, quantification of redox activity of non enzymatic antioxidant compounds and gene expression profiling provide deeper insights to study seed viability during storage. Telomere lengthening is a promising tool to discriminate between short- and long-lived species

Neural network identification of people hidden from view with a single-pixel, single-photon detector

Light scattered from multiple surfaces can be used to retrieve information of hidden environments. However, full three-dimensional retrieval of an object hidden from view by a wall has only been achieved with scanning systems and requires intensive computational processing of the retrieved data. Here we use a non-scanning, single-photon single-pixel detector in combination with a deep convolutional artificial neural network: this allows us to locate the position and to also simultaneously provide the actual identity of a hidden person, chosen from a database of people (N = 3). Artificial neural networks applied to specific computational imaging problems can therefore enable novel imaging capabilities with hugely simplified hardware and processing times

Assessment of power spectral density of microvascular hemodynamics in skeletal muscles at very low and low-frequency via near-infrared diffuse optical spectroscopies

In this work, we used a hybrid time domain near-infrared spectroscopy (TD-NIRS) and diffuse correlation spectroscopy (DCS) device to retrieve hemoglobin and blood flow oscillations of skeletal muscle microvasculature. We focused on very low (VLF) and low-frequency (LF) oscillations (i.e., frequency lower than 0.145 Hz), that are related to myogenic, neurogenic and endothelial activities. We measured power spectral density (PSD) of blood flow and hemoglobin concentration in four muscles (thenar eminence, plantar fascia, sternocleidomastoid and forearm) of 14 healthy volunteers to highlight possible differences in microvascular hemodynamic oscillations. We observed larger PSDs for blood flow compared to hemoglobin concentration, in particular in case of distal muscles (i.e., thenar eminence and plantar fascia). Finally, we compared the PSDs measured on the thenar eminence of healthy subjects with the ones measured on a septic patient in the intensive care unit: lower power in the endothelial-dependent frequency band, and larger power in the myogenic ones were observed in the septic patient, in accordance with previous works based on laser doppler flowmetry

In vivo characterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle through ultrasound-guided hybrid near-infrared spectroscopies

Objective. In this paper, we present a detailed in vivo characterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle (SCM), obtained through ultrasound-guided near-infrared time-domain and diffuse correlation spectroscopies. Approach. A total of sixty-five subjects (forty-nine females, sixteen males) among healthy volunteers and thyroid nodule patients have been recruited for the study. Their SCM hemodynamic (oxy-, deoxy- and total hemoglobin concentrations, blood flow, blood oxygen saturation and metabolic rate of oxygen extraction) and optical properties (wavelength dependent absorption and reduced scattering coefficients) have been measured by the use of a novel hybrid device combining in a single unit time-domain near-infrared spectroscopy, diffuse correlation spectroscopy and simultaneous ultrasound imaging. Main results. We provide detailed tables of the results related to SCM baseline (i.e. muscle at rest) properties, and reveal significant differences on the measured parameters due to variables such as side of the neck, sex, age, body mass index, depth and thickness of the muscle, allowing future clinical studies to take into account such dependencies. Significance. The non-invasive monitoring of the hemodynamics and metabolism of the sternocleidomastoid muscle during respiration became a topic of increased interest partially due to the increased use of mechanical ventilation during the COVID-19 pandemic. Near-infrared diffuse optical spectroscopies were proposed as potential practical monitors of increased recruitment of SCM during respiratory distress. They can provide clinically relevant information on the degree of the patient's respiratory effort that is needed to maintain an optimal minute ventilation, with potential clinical application ranging from evaluating chronic pulmonary diseases to more acute settings, such as acute respiratory failure, or to determine the readiness to wean from invasive mechanical ventilation.</p

A multi-laboratory comparison of photon migration instruments and their performances – the BitMap Exercise

Performance assessment and standardization are indispensable for instruments of clinical relevance in general and clinical instrumentation based on photon migration/diffuse optics in particular. In this direction, a multi-laboratory exercise was initiated with the aim of assessing and comparing their performances. 29 diffuse optical instruments belonging to 11 partner institutions of a European level Marie Curie Consortium BitMap1 were considered for this exercise. The enrolled instruments covered different approaches (continuous wave, CW; frequency domain, FD; time domain, TD and spatial frequency domain imaging, SFDI) and applications (e.g. mammography, oximetry, functional imaging, tissue spectroscopy). 10 different tests from 3 well-accepted protocols, namely, the MEDPHOT2, the BIP3, and the nEUROPt4 protocols were chosen for the exercise and the necessary phantoms kits were circulated across labs and institutions enrolled in the study. A brief outline of the methodology of the exercise is presented here. Mainly, the design of some of the synthetic descriptors, (single numeric values used to summarize the result of a test and facilitate comparison between instruments) for some of the tests will be discussed.. Future actions of the exercise aim at deploying these measurements onto an open data repository and investigating common analysis tools for the whole dataset

Multi-laboratory efforts for the standardization of performance assessment of diffuse optics instruments - The BitMap Exercise

A multi-laboratory exercise, involving 29 diffuse optical instruments, aimed at performance assessment of diffuse optics instruments on standardized protocols is presented. The overarching methodology and future actions will also be discussed

VASCOVID: hybrid diffuse optical platform combined with a pulse-oximeter and an automatized inflatable tourniquet for the assessment of metabolism and endothelial health in the intensive care

VASCOVID project is developing and testing a hybrid diffuse optical monitor for evaluating endothelial function and metabolism in intensive care including COVID-19