Precision sampling of discrete sites identified during in-vivo functional testing in the mammalian heart.

Ventricular arrhythmias after myocardial infarction (MI) originate from discrete areas within the MI border zone (BZ), identified during functional electrophysiology tests. Accurate sampling of arrhythmogenic sites for ex-vivo study remains challenging, yet is critical to identify their tissue, cellular and molecular signature. In this study, we developed, validated, and applied a targeted sampling methodology based on individualized 3D prints of the human-sized pig heart.

High-Yield Production of SiV-Doped Nanodiamonds for Spectroscopy and Sensing Applications.

Nanodiamonds (NDs) containing optically active centers have gained significant relevance as the material of choice for biological, optoelectronic, and quantum applications. However, current production methods lag behind their real needs. This study introduces two CVD-based approaches for fabricating NDs with optically active silicon-vacancy (SiV) color centers: bottom-up (BU) and top-down (TD) methods.

Influence of a Solid Surface on PNIPAM Microgel Films.

Stimuli-responsive microgels have attracted great interest in recent years as building blocks for fabricating smart surfaces with many technological applications. In particular, PNIPAM microgels are promising candidates for creating thermo-responsive scaffolds to control cell growth and detachment via temperature stimuli. In this framework, understanding the influence of the solid substrate is critical for tailoring microgel coatings to specific applications.

Synthesis and superconductivity in yttrium-cerium hydrides at high pressures.

Further increasing the critical temperature and/or decreasing the stabilized pressure are the general hopes for the hydride superconductors. Inspired by the low stabilized pressure associated with Ce 4f electrons in superconducting cerium superhydride and the high critical temperature in yttrium superhydride, we carry out seven independent runs to synthesize yttrium-cerium alloy hydrides. The synthetic process is examined by the Raman scattering and X-ray diffraction measurements.

Synthesis of superconducting phase of LaCeHat high pressures.

Clathrate hydrideFm3-m-LaHhas been proven as the most extraordinary superconductor with the critical temperatureabove 250 K upon compression of hundreds of GPa in recent years. A general hope is to reduce the stabilization pressure and maintain the highvalue of the specific phase in LaH. However, strong structural instability distortsFm3-mstructure and leads to a rapid decrease ofat low pressures.

Optogenetic manipulation of cardiac repolarization gradients using sub-threshold illumination.

Mechanisms underlying cardiac arrhythmias are typically driven by abnormalities in cardiac conduction and/or heterogeneities in repolarization time (RT) across the heart. While conduction slowing can be caused by either electrophysiological defects or physical blockade in cardiac tissue, RT heterogeneities are mainly related to action potential (AP) prolongation or abbreviation in specific areas of the heart. Importantly, the size of the area with altered RT and the difference between the short RT and long RT (RT gradient) have been identified as critical determinators of arrhythmogenicity.

Optogenetic manipulation of cardiac electrical dynamics using sub-threshold illumination: dissecting the role of cardiac alternans in terminating rapid rhythms.

Cardiac action potential (AP) shape and propagation are regulated by several key dynamic factors such as ion channel recovery and intracellular Ca cycling. Experimental methods for manipulating AP electrical dynamics commonly use ion channel inhibitors that lack spatial and temporal specificity. In this work, we propose an approach based on optogenetics to manipulate cardiac electrical activity employing a light-modulated depolarizing current with intensities that are too low to elicit APs (sub-threshold illumination), but are sufficient to fine-tune AP electrical dynamics.

A junctional cAMP compartment regulates rapid Ca signaling in atrial myocytes.

Axial tubule junctions with the sarcoplasmic reticulum control the rapid intracellular Ca-induced Ca release that initiates atrial contraction. In atrial myocytes we previously identified a constitutively increased ryanodine receptor (RyR2) phosphorylation at junctional Ca release sites, whereas non-junctional RyR2 clusters were phosphorylated acutely following β-adrenergic stimulation. Here, we hypothesized that the baseline synthesis of 3',5'-cyclic adenosine monophosphate (cAMP) is constitutively augmented in the axial tubule junctional compartments of atrial myocytes.

Revealing Underdrawings in Wall Paintings of Complex Stratigraphy with a Novel Reflectance Photoacoustic Imaging Prototype.

Revealing precious hidden features by a completely non-invasive approach is one of the crucial issues in the Heritage Science field. In this regard, concealed fresco paintings still represent an analytical challenge. This paper addresses the specific issue in wall painting diagnostics by the photoacoustic (PA) imaging technique, already proven to be efficient in revealing underdrawings and internal stratigraphy in movable paintings on paper and canvas.

Revealing Hidden Features in Multilayered Artworks by Means of an Epi-Illumination Photoacoustic Imaging System.

Photoacoustic imaging is a novel, rapidly expanding technique, which has recently found several applications in artwork diagnostics, including the uncovering of hidden layers in paintings and multilayered documents, as well as the thickness measurement of optically turbid paint layers with high accuracy. However, thus far, all the presented photoacoustic-based imaging technologies dedicated to such measurements have been strictly limited to thin objects due to the detection of signals in transmission geometry. Unavoidably, this issue restricts seriously the applicability of the imaging method, hindering investigations over a wide range of cultural heritage objects with diverse geometrical and structural features.

Advances in Stem Cell Modeling of Dystrophin-Associated Disease: Implications for the Wider World of Dilated Cardiomyopathy.

Familial dilated cardiomyopathy (DCM) is mostly caused by mutations in genes encoding cytoskeletal and sarcomeric proteins. In the pediatric population, DCM is the predominant type of primitive myocardial disease. A severe form of DCM is associated with mutations in the gene encoding dystrophin, which are the cause of Duchenne Muscular Dystrophy (DMD).

Experimental study of the mechanisms leading to the formation of glistenings in intraocular lenses by Raman spectroscopy.

The phenomenon of glistenings, often appearing in intraocular lenses (IOLs) of patients after some time from the surgical operation, is potentially able to induce a poor quality of vision and, therefore, frustrate IOL implantation itself. In this paper, we combine optical microscopy with micro-Raman spectroscopy to get a deeper insight on the mechanism ruling, at microscopic scale, glistening formation. In particular, we have analyzed two types of IOLs, characterized by a different internal hydrophobicity but a similar polymer hydration coefficient.

Plasmon-Assisted Suppression of Surface Trap States and Enhanced Band-Edge Emission in a Bare CdTe Quantum Dot.

Colloidal quantum dots have emerged as a versatile photoluminescent and optoelectronic material. Limitations like fluorescence intermittency, nonradiative Auger recombination, and surface traps are commonly addressed by growing a wide-band-gap shell. However, the shell isolates the excitonic wave function and reduces its interaction with the external environment necessary for different applications.

Axial Tubule Junctions Activate Atrial Ca Release Across Species.

Recently, abundant axial tubule (AT) membrane structures were identified deep inside atrial myocytes (AMs). Upon excitation, ATs rapidly activate intracellular Ca release and sarcomeric contraction through extensive AT junctions, a cell-specific atrial mechanism. While AT junctions with the sarcoplasmic reticulum contain unusually large clusters of ryanodine receptor 2 (RyR2) Ca release channels in mouse AMs, it remains unclear if similar protein networks and membrane structures exist across species, particularly those relevant for atrial disease modeling.

Using Optical Coherence Tomography to Reveal the Hidden History of The Landsdowne Virgin of the Yarnwinder by Leonardo da Vinci and Studio.

Optical coherence tomography (OCT) was used for non-invasive examination of a well-known, yet complex, painting from the studio of Leonardo da Vinci in combination with routine imaging in various bands of electromagnetic radiation. In contrast with these techniques, OCT provides depth-resolved information. Three post-processing modalities were explored: cross-sectional views, maps of scattering from given depths, and their 3D models.

Pathogenesis of Hypertrophic Cardiomyopathy is Mutation Rather Than Disease Specific: A Comparison of the Cardiac Troponin T E163R and R92Q Mouse Models.

Background: In cardiomyocytes from patients with hypertrophic cardiomyopathy, mechanical dysfunction and arrhythmogenicity are caused by mutation-driven changes in myofilament function combined with excitation-contraction (E-C) coupling abnormalities related to adverse remodeling. Whether myofilament or E-C coupling alterations are more relevant in disease development is unknown. Here, we aim to investigate whether the relative roles of myofilament dysfunction and E-C coupling remodeling in determining the hypertrophic cardiomyopathy phenotype are mutation specific.

Ranolazine Prevents Phenotype Development in a Mouse Model of Hypertrophic Cardiomyopathy.

Background: Current therapies are ineffective in preventing the development of cardiac phenotype in young carriers of mutations associated with hypertrophic cardiomyopathy (HCM). Ranolazine, a late Na current blocker, reduced the electromechanical dysfunction of human HCM myocardium in vitro.

Methods And Results: To test whether long-term treatment prevents cardiomyopathy in vivo, transgenic mice harboring the R92Q troponin-T mutation and wild-type littermates received an oral lifelong treatment with ranolazine and were compared with age-matched vehicle-treated animals.

Coherent interaction of light with a metallic structure coupled to a single quantum emitter: from superabsorption to cloaking.

We provide a general theoretical platform based on quantized radiation in absorptive and inhomogeneous media for investigating the coherent interaction of light with material structures in the immediate vicinity of quantum emitters. In the case of a very small metallic cluster, we demonstrate extreme regimes where a single emitter can either counteract or enhance particle absorption by 3 orders of magnitude. For larger structures, we show that an emitter can eliminate both scattering and absorption and cloak a plasmonic antenna.