Fast data fitting scheme for compressive multispectral fluorescence lifetime imaging.

A single-pixel camera combined with compressive sensing techniques is a promising fluorescence microscope scheme for acquiring a multidimensional dataset (space, spectrum, and lifetime) and for reducing the measurement time with respect to conventional microscope schemes. However, upon completing the acquisition, a computational step is necessary for image reconstruction and data analysis, which can be time-consuming, potentially canceling out the beneficial effect of compressive sensing. In this work, we propose and experimentally validate a fast-fit workflow based on global analysis and multiple linear fits, which significantly reduces the computation time from tens of minutes to less than 1 s. Moreover, as the method is interlaced with the measurement flow, it can be applied in parallel with the acquisitions.

Plasmonic titanium nitride nanomaterials prepared by physical vapor deposition methods.

Titanium nitride (TiN) has recently emerged as an alternative to coinage metals to enable the development of integrated plasmonic devices at visible and medium-infrared wavelengths. In this regard, its optical performance can be conveniently tuned by tailoring the process parameters of physical vapor deposition methods, such as magnetron sputtering and pulsed laser deposition (PLD). This review first introduces the fundamental features of TiN and a description on its optical properties, including insights on the main experimental techniques to measure them. Afterwards, magnetron sputtering and PLD are selected as fabrication techniques for TiN nanomaterials. The fundamental mechanistic aspects of both techniques are discussed in parallel with selected case studies from the recent literature, which elucidate the critical advantages of such techniques to engineer the nanostructure and the plasmonic performance of TiN.

The structural bases for agonist diversity in an Arabidopsis thaliana glutamate receptor-like channel.

Arabidopsis thaliana glutamate receptor-like (GLR) channels are amino acid-gated ion channels involved in physiological processes including wound signaling, stomatal regulation, and pollen tube growth. Here, fluorescence microscopy and genetics were used to confirm the central role of GLR3.3 in the amino acid-elicited cytosolic Ca2+ increase in Arabidopsis seedling roots. To elucidate the binding properties of the receptor, we biochemically reconstituted the GLR3.3 ligand-binding domain (LBD) and analyzed its selectivity profile; our binding experiments revealed the LBD preference for l-Glu but also for sulfur-containing amino acids. Furthermore, we solved the crystal structures of the GLR3.3 LBD in complex with 4 different amino acid ligands, providing a rationale for how the LBD binding site evolved to accommodate diverse amino acids, thus laying the grounds for rational mutagenesis. Last, we inspected the structures of LBDs from nonplant species and generated homology models for other GLR isoforms. Our results establish that GLR3.3 is a receptor endowed with a unique amino acid ligand profile and provide a structural framework for engineering this and other GLR isoforms to investigate their physiology.

Zinc Electrode Cycling in Deep Eutectic Solvent Electrolytes: An Electrochemical Study.

Among post-lithium ion battery technologies, rechargeable chemistries with Zn anodes bear notable technological promise owing to their high theoretical energy density, lower manufacturing cost, availability of raw materials and inherent safety. However, Zn anodes, when employed in aqueous electrolytes, suffer from hydrogen evolution, passivation, and shape changes. Alternative electrolytes can help tackle these issues, preserving the green and safe characteristics of aqueous-based ones. Deep eutectic solvents (DESs) are promising green and low-cost non-aqueous solvents for battery electrolytes. Specifically, the cycling of Zn anodes in DESs is expected to be reversible, chiefly owing to their dendrite-suppression capability. Nevertheless, apart from a few studies on Zn plating, insight into the cathodic-anodic electrochemistry of Zn in DESs is still very limited. In view of developing DES-based battery electrolytes, it is crucial to consider that a potential drawback might be their low ionic conductivity. Water molecules can be added to the eutectic mixtures by up to 40% to increase the diffusion coefficient of the electroactive species and lower the electrolyte viscosity without destroying the eutectic nature. In this study, we address the electrochemistry of Zn in two different hydrated DESs (ChU and ChEG with ~30% H2O). Fundamental electrokinetic and electrocrystallization studies based on cyclic voltammetry and chronoamperometry at different cathodic substrates are completed with a galvanostatic cycling test of Zn|Zn symmetric CR2032 coin cells, SEM imaging of electrodes and in situ SERS spectroscopy. This investigation concludes with the proposal of a specific DES/H2O/ZnSO4-based electrolyte that exhibits optimal functional performance, rationalized on the basis of fundamental electrochemical data, morphology evaluation and modeling of the cycling response.

New Mechanism for Long Photo-Induced Enhanced Raman Spectroscopy in Au Nanoparticles Embedded in TiO2.

The photo-induced enhanced Raman spectroscopy (PIERS) effect is a phenomenon taking place when plasmonic nanoparticles deposited on a semiconductor are illuminated by UV light prior to Raman measurement. Results from the literature show that the PIERS effect lasts for about an hour. The proposed mechanism for this effect is the creation of oxygen vacancies in the semiconductor that would create a path for charge transfer between the analyte and the nanoparticles. However, this hypothesis has never been confirmed experimentally. Furthermore, the tested structure of the PIERS substrate has always been composed of plasmonic nanoparticles deposited on top of the semiconductor. Here, gold nanoparticles co-deposited with porous TiO2 are used as a PIERS substrate. The deposition process confers the nanoparticles a unique position half buried in the nanoporous semiconductor. The resulting PIERS intensity is among the highest measured until now but most importantly the duration of the effect is significantly longer (at least 8 days). Cathodoluminescence measurements on these samples show that two distinct mechanisms are at stake for co-deposited and drop-casted gold nanoparticles. The oxygen vacancies hypothesis tends to be confirmed for the latter, but the narrowing of the depletion zone explains the long PIERS effect.

Simultaneous imaging of ER and cytosolic Ca2+ dynamics reveals long-distance ER Ca2+ waves in plants.

Calcium ions (Ca2+) play a key role in cell signaling across organisms. In plants, a plethora of environmental and developmental stimuli induce specific Ca2+ increases in the cytosol as well as in different cellular compartments including the endoplasmic reticulum (ER). The ER represents an intracellular Ca2+ store that actively accumulates Ca2+ taken up from the cytosol. By exploiting state-of-the-art genetically encoded Ca2+ indicators, specifically the ER-GCaMP6-210 and R-GECO1, we report the generation and characterization of an Arabidopsis (Arabidopsis thaliana) line that allows for simultaneous imaging of Ca2+ dynamics in both the ER and cytosol at different spatial scales. By performing analyses in single cells, we precisely quantified (1) the time required by the ER to import Ca2+ from the cytosol into the lumen and (2) the time required to observe a cytosolic Ca2+ increase upon the pharmacological inhibition of the ER-localized P-Type IIA Ca2+-ATPases. Furthermore, live imaging of mature, soil-grown plants revealed the existence of a wounding-induced, long-distance ER Ca2+ wave propagating in injured and systemic rosette leaves. This technology enhances high-resolution analyses of intracellular Ca2+ dynamics at the cellular level and in adult organisms and paves the way to develop new methodologies aimed at defining the contribution of subcellular compartments in Ca2+ homeostasis and signaling.

Integrated optical device for Structured Illumination Microscopy.

Structured Illumination Microscopy (SIM) is a key technology for high resolution and super-resolution imaging of biological cells and molecules. The spread of portable and easy-to-align SIM systems requires the development of novel methods to generate a light pattern and to shift it across the field of view of the microscope. Here we show a miniaturized chip that incorporates optical waveguides, splitters, and phase shifters, to generate a 2D structured illumination pattern suitable for SIM microscopy. The chip creates three point-sources, coherent and controlled in phase, without the need for further alignment. Placed in the pupil of a microscope's objective, the three sources generate a hexagonal illumination pattern on the sample, which is spatially translated thanks to thermal phase shifters. We validate and use the chip, upgrading a commercial inverted fluorescence microscope to a SIM setup and we image biological sample slides, extending the resolution of the microscope.

Infantile hemangiomas ß3-adrenoceptor overexpression is associated with nonresponse to propranolol.

BACKGROUND: Propranolol (antagonist of ß1-/ß2-AR but minimally active against ß3-AR) is currently the first-line treatment for infantile hemangiomas (IH). Its efficacy is attributed to the blockade of ß2-AR. However, its success rate is ~60%. Considering the growing interest in the angiogenic role of ß3-ARs, we evaluated a possible relationship between ß3-AR expression and response to propranolol. METHODS: Fifteen samples of surgical biopsies were collected from patients with IH. Three were taken precociously from infants and then successfully treated with propranolol (responder group). Twelve were taken later, from residual lesions noncompletely responsive to propranolol (nonresponder group). A morphometrical analysis of the percentage of ß1-, ß2-, and ß3-ARs positively stained area was compared between the two groups. RESULTS: While no difference was found in both ß1- and ß2-AR expression level, a statistically significant increase of ß3-AR positively stained area was observed in the nonresponder group. CONCLUSIONS: Although the number of biopsies is insufficient to draw definitive conclusions, and the different ß-AR pattern may be theoretically explained by the different timing of samplings, this study suggests a possible correlation between ß3-AR expression and the reduced responsiveness to propranolol treatment. This study could pave the way for new therapeutic perspectives to manage IH. IMPACT: Propranolol (unselective antagonist of ß1 and ß2-ARs) is currently the first-line treatment for IHs, with a success rate of ~60%. Its effectiveness has been attributed to its ability to block ß2-ARs. However, ß3-ARs (on which propranolol is minimally active) were significantly more expressed in hemangioma biopsies taken from patients nonresponsive to propranolol. This study suggests a possible role of ß3-ARs in hemangioma pathogenesis and a possible new therapeutic target.

Steric hindrance in the on-surface synthesis of diethynyl-linked anthracene polymers.

Hybrid sp-sp2 structures can be efficiently obtained on metal substrates via on-surface synthesis. The choice of both the precursor and the substrate impacts on the effectiveness of the process and the stability of the formed structures. Here we demonstrate that using anthracene-based precursor molecules on Au(111) the formation of polymers hosting sp carbon chains is affected by the steric hindrance between aromatic groups. In particular, by scanning tunneling microscopy experiments and density functional theory simulations we show that the de-metalation of organometallic structures induces a lateral separation of adjacent polymers that prevents the formation of ordered domains. This study contributes to the understanding of the mechanisms driving the on-surface synthesis processes, a fundamental step toward the realization of novel carbon-based nanostructures with perspective applications in nanocatalysis, photoconversion, and nano-electronics.

Oral cinnarizine for the treatment of COVID-19-associated chilblain-like lesions: An old drug for a new disease?

During SARS-CoV-2 pandemic, an outbreak of chilblain-like lesions has been developed, even if the relationship with the virus infection is still debated. We report the good results obtained in 12 patients with chilblain lesions and the use of oral cinnarizine, a piperazine derivative with many pharmacological properties among whom antihistaminic and calcium channel blocking activities.

Enlarged Field of View in Spatially Modulated Selective Volume Illumination Microscopy.

Three-dimensional fluorescence microscopy is a key technology for inspecting biological samples, ranging from single cells to entire organisms. We recently proposed a novel approach called spatially modulated Selective Volume Illumination Microscopy (smSVIM) to suppress illumination artifacts and to reduce the required number of measurements using an LED source. Here, we discuss a new strategy based on smSVIM for imaging large transparent specimens or voluminous chemically cleared tissues. The strategy permits steady mounting of the sample, achieving uniform resolution over a large field of view thanks to the synchronized motion of the illumination lens and the camera rolling shutter. Aided by a tailored deconvolution method for image reconstruction, we demonstrate significant improvement of the resolution at different magnification using samples of varying sizes and spatial features.

Modeling Lung Carcinoids with Zebrafish Tumor Xenograft.

Lung carcinoids are neuroendocrine tumors that comprise well-differentiated typical (TCs) and atypical carcinoids (ACs). Preclinical models are indispensable for cancer drug screening since current therapies for advanced carcinoids are not curative. We aimed to develop a novel in vivo model of lung carcinoids based on the xenograft of lung TC (NCI-H835, UMC-11, and NCI-H727) and AC (NCI-H720) cell lines and patient-derived cell cultures in Tg(fli1a:EGFP)y1 zebrafish embryos. We exploited this platform to test the anti-tumor activity of sulfatinib. The tumorigenic potential of TC and AC implanted cells was evaluated by the quantification of tumor-induced angiogenesis and tumor cell migration as early as 24 h post-injection (hpi). The characterization of tumor-induced angiogenesis was performed in vivo and in real time, coupling the tumor xenograft with selective plane illumination microscopy on implanted zebrafish embryos. TC-implanted cells displayed a higher pro-angiogenic potential compared to AC cells, which inversely showed a relevant migratory behavior within 48 hpi. Sulfatinib inhibited tumor-induced angiogenesis, without affecting tumor cell spread in both TC and AC implanted embryos. In conclusion, zebrafish embryos implanted with TC and AC cells faithfully recapitulate the tumor behavior of human lung carcinoids and appear to be a promising platform for drug screening.

Spinning pupil aberration measurement for anisoplanatic deconvolution.

The aberrations in an optical microscope are commonly measured and corrected at one location in the field of view, within the so-called isoplanatic patch. Full-field correction is desirable for high-resolution imaging of large specimens. Here we present, to the best of our knowledge, a novel wavefront detector, based on pupil sampling with subapertures, measuring the aberrated wavefront phase at each position of the specimen. Based on this measurement, we propose a region-wise deconvolution that provides an anisoplanatic reconstruction of the sample image. Our results indicate that the measurement and correction of the aberrations can be performed in a wide-field fluorescence microscope over its entire field of view.

Multispectral compressive fluorescence lifetime imaging microscopy with a SPAD array detector.

Multispectral/hyperspectral fluorescence lifetime imaging microscopy (λFLIM) is a promising tool for studying functional and structural biological processes. The rich information content provided by a multidimensional dataset is often in contrast with the acquisition speed. In this work, we develop and experimentally demonstrate a wide-field λFLIM setup, based on a novel time-resolved 18×1 single-photon avalanche diode array detector working in a single-pixel camera scheme, which parallelizes the spectral detection, reducing measurement time. The proposed system, which implements a single-pixel camera with a compressive sensing scheme, represents an optimal microscopy framework towards the design of λFLIM setups.

QUAREP-LiMi: A community-driven initiative to establish guidelines for quality assessment and reproducibility for instruments and images in light microscopy.

A modern day light microscope has evolved from a tool devoted to making primarily empirical observations to what is now a sophisticated , quantitative device that is an integral part of both physical and life science research. Nowadays, microscopes are found in nearly every experimental laboratory. However, despite their prevalent use in capturing and quantifying scientific phenomena, neither a thorough understanding of the principles underlying quantitative imaging techniques nor appropriate knowledge of how to calibrate, operate and maintain microscopes can be taken for granted. This is clearly demonstrated by the well-documented and widespread difficulties that are routinely encountered in evaluating acquired data and reproducing scientific experiments. Indeed, studies have shown that more than 70% of researchers have tried and failed to repeat another scientist's experiments, while more than half have even failed to reproduce their own experiments. One factor behind the reproducibility crisis of experiments published in scientific journals is the frequent underreporting of imaging methods caused by a lack of awareness and/or a lack of knowledge of the applied technique. Whereas quality control procedures for some methods used in biomedical research, such as genomics (e.g. DNA sequencing, RNA-seq) or cytometry, have been introduced (e.g. ENCODE), this issue has not been tackled for optical microscopy instrumentation and images. Although many calibration standards and protocols have been published, there is a lack of awareness and agreement on common standards and guidelines for quality assessment and reproducibility. In April 2020, the QUality Assessment and REProducibility for instruments and images in Light Microscopy (QUAREP-LiMi) initiative was formed. This initiative comprises imaging scientists from academia and industry who share a common interest in achieving a better understanding of the performance and limitations of microscopes and improved quality control (QC) in light microscopy. The ultimate goal of the QUAREP-LiMi initiative is to establish a set of common QC standards, guidelines, metadata models and tools, including detailed protocols, with the ultimate aim of improving reproducible advances in scientific research. This White Paper (1) summarizes the major obstacles identified in the field that motivated the launch of the QUAREP-LiMi initiative; (2) identifies the urgent need to address these obstacles in a grassroots manner, through a community of stakeholders including, researchers, imaging scientists, bioimage analysts, bioimage informatics developers, corporate partners, funding agencies, standards organizations, scientific publishers and observers of such; (3) outlines the current actions of the QUAREP-LiMi initiative and (4) proposes future steps that can be taken to improve the dissemination and acceptance of the proposed guidelines to manage QC. To summarize, the principal goal of the QUAREP-LiMi initiative is to improve the overall quality and reproducibility of light microscope image data by introducing broadly accepted standard practices and accurately captured image data metrics.

Comparing the sensitivities of two screening tests in nonblinded randomized paired screen-positive trials with differential screening uptake.

Before a new screening test can be used in routine screening, its performance needs to be compared to the standard screening test. This comparison is generally done in population screening trials with a screen-positive design where participants undergo one or both screening tests after which disease verification takes place for those positive on at least one screening test. We consider the randomized paired screen-positive design of Alonzo and Kittelson where participants are randomized to receive one of the two screening tests and only participants with a positive screening test subsequently receive the other screening test followed by disease verification. The tests are usually offered in an unblinded fashion in which case the screening uptake may differ between arms, in particular when one test is more burdensome than the other. When uptake is associated with disease, the estimator for the relative sensitivity derived by Alonzo and Kittelson may be biased and the type I error of the associated statistical test is no longer guaranteed to be controlled. We present methods for comparing sensitivities of screening tests in randomized paired screen-positive trials that are robust to differential screening uptake. In a simulation study, we show that our methods adequately control the type I error when screening uptake is associated with disease. We apply the developed methods to data from the IMPROVE trial, a nonblinded cervical cancer screening trial comparing the accuracy of HPV testing on self-collected versus provider-collected samples. In this trial, screening uptake was higher among participants randomized to self-collection.

Viral rashes mimicking drug reaction with eosinophilia and systemic symptoms syndrome in children after ß-lactams intake: a diagnostic challenge.

In cases of skin eruptions over the course of antibiotic therapy and concomitant viral infection, differential diagnosis is often challenging. Confirming or ruling out drug hypersensitivity is not always a clear-cut question. Drug reaction with eosinophilia and systemic symptoms (DRESS) cases, for example, is classified as severe cutaneous adverse reactions due to drugs, but frequently the clinical manifestations do not completely fit into the diagnosis of DRESS. The aim of the present paper is to highlight similarities and differences among DRESS syndrome and DRESS-like rashes during viral infections and amoxicillin intake in children, in order to highlight those aspects that can help clinicians in early detection. We describe the dermatological, clinical, and laboratory characteristics of five patients hospitalized for DRESS-like skin rashes appearing roughly 1 week since the start of an amoxicillina course for upper respiratory tract infection (URTI) symptoms. The data are compared with those of 3 patients with early-onset DRESS syndrome. The absence of eosinophilia might be an initial marker to help identifying DRESS-like rashes; a quick clinical improvement and the confirmation of a viral infection able to explain the symptoms can help to finally rule out DRESS syndrome. Conclusion: A rapid, correct diagnosis of such DRESS-like rashes during viral infections allows more appropriate management and avoids unnecessary, life-long exclusion of useful and effective antibiotics because of a falsely "amoxicillin-allergy" labelling. What is Known: • Viral infections are common causes of skin rashes in children during antibiotic intake and may require differential diagnosis with drug reactions. • Early-onset DRESS syndrome is usually induced by antibiotics and appears ≤15 days after drug intake. What is New: • Prominent midface edema, maculopapular rash, and mild-to-moderate systemic symptoms may appear in children during viral illnesses treated with amoxicillin few days after drug intake, and may require differential diagnosis with early-onset DRESS. • In such cases, absence of eosinophilia, low (2-3) RegiSCAR score, confirmation of viral etiology, and a rapid resolution of the rash (2-5 days) might help to rule out DRESS; conversely, at an early stage, the presence of eosinophilia should suggest a diagnosis of DRESS.

Lichen sclerosus with enlarged vessels: A variant of lichen sclerosus in young girls.

Vascular findings have rarely been described in the setting of lichen sclerosus. Enlarged vessels within the atrophic plaques have been observed on the free margins of the labia minora and clitoral hood. The enlarged vessels completely remit upon treatment of lichen sclerosus with an ultra-potent corticosteroid ointment in the acute phase. During maintenance therapy with calcineurin inhibitors, there was no recurrence of the enlarged vessels.

Nail changes in children with idiopathic congenital clubfoot deformity.

BACKGROUND/OBJECTIVES: Nail alterations are commonly seen in cases of idiopathic clubfoot and may cause parental concern. The nature of and whether these changes are congenital or develop secondary to treatment has been poorly investigated. The aim of this study was to evaluate toenail morphology in clubfoot patients at presentation, to re-evaluate them during the course of treatment for the clubfoot, and to analyze findings in the light of the few literature reports for healthy children of the same age. METHODS: Thirty infants (21 males and 9 females) with idiopathic clubfoot were prospectively enrolled at the Anna Meyer Children's University Hospital. Nails of affected and non-affected feet were evaluated by a team of pediatric dermatologists at presentation and re-evaluated once per patient during the bracing period of Ponseti treatment. RESULTS: Toenails of affected (47) and non-affected (13) feet were abnormal at presentation in 43.3% of patients, in both clubfeet (40.4%) and non-affected feet (38.5%), but most changes were physiologic or transitory alterations, commonly found in healthy children, with nail concavity (koilonychia) being the most common finding (29.7%). Changes were not related to clubfoot severity or laterality (P > .05). In most (76.9%) unilateral cases, there was concordance of nail changes between clubfoot and non-affected foot. At re-evaluation (follow-up time 410 ± 207 days), nail problems were more frequent (53.3%); ingrown toenail was the most common (21.6%). CONCLUSIONS: The presence of nail alterations seems not to be caused by clubfoot pathology and could be related to unfavorable local condition in the brace.

Integration of Transparent Supercapacitors and Electrodes Using Nanostructured Metallic Glass Films for Wirelessly Rechargeable, Skin Heat Patches.

Here we demonstrate an unconventional fabrication of highly transparent supercapacitors and electrodes using random networks of nanostructured metallic glass nanotroughs for their integrations as wirelessly rechargeable and invisible, skin heat patches. Transparent supercapacitors with fine conductive patterns were printed using an electrohydrodynamic jet-printing. Also, transparent and stretchable electrodes, for wireless antennas, heaters and interconnects, were formed using random network based on nanostructured CuZr nanotroughs and Ag nanowires with superb optoelectronic properties (sheet resistance of 3.0 Ω/sq at transmittance of 91.1%). Their full integrations, as an invisible heat patch on skin, enabled the wireless recharge of supercapacitors and the functions of heaters for thermal therapy of skin tissue. The demonstration of this transparent thermotherapy patch to control the blood perfusion level and hydration rate of skin suggests a promising strategy toward next-generation wearable electronics.