Strong Laser Emission Modulation by Coherent Perfect Absorption Inside Complex-Coupled Distributed Feedback Laser Diodes.

The proof-of-concept of the exploitation of Coherent Perfect Absorption (CPA) in electrically-injected distributed-feedback laser sources is reported. Capitalizing on the essence of CPA as "light extinction by light", an integrated laser-modulator scheme emerges. The key ingredient compared to conventional single-frequency laser diodes is a careful periodic in-phase modulation of both real and imaginary parts of the complex grating index profile that enables both single-frequency operation and 40 dB line purity at the Bragg frequency.

Better together: A systematic review of studies combining magnetic resonance imaging with ecological momentary assessment.

Social neuroscientists often use magnetic resonance imaging (MRI) to understand the relationship between social experiences and their neural substrates. Although MRI is a powerful method, it has several limitations in the study of social experiences, first and foremost its low ecological validity. To address this limitation, researchers have conducted multimethod studies combining MRI with Ecological Momentary Assessment (EMA).

Back to Normal? Harnessing Long Short-term Memory Network to Examine the Associations Between Adolescent Social Interactions and Depressive Symptoms During Different Stages of COVID-19.

Adolescence is a developmental period in which social interactions are critical for mental health. While the onset of COVID-19 significantly disrupted adolescents' social environments and mental health, it remains unclear how adolescents have adapted to later stages of the pandemic. We harnessed a machine learning architecture of Long Short-Term Memory recurrent networks (LSTM) with gradient-based feature importance, to model the association among daily social interactions and depressive symptoms during three stages of the pandemic.

Stability mapping of bipartite tight-binding graphs with losses and gain: PTPT-symmetry and beyond.

We consider bipartite tight-binding graphs composed by N nodes split into two sets of equal size: one set containing nodes with on-site loss, the other set having nodes with on-site gain. The nodes are connected randomly with probability p. Specifically, we measure the connectivity between the two sets with the parameter α, which is the ratio of current adjacent pairs over the total number of possible adjacent pairs between the sets.

Engineering of the Fano resonance spectral response with non-Hermitian metasurfaces by navigating between exceptional point and bound states in the continuum conditions.

We address the engineering of Fano resonances and metasurfaces, by placing it in the general context of open non-Hermitian systems composed of coupled antenna-type resonators. We show that eigenfrequency solutions obtained for a particular case of scattering matrix are general and valid for arbitrary antenna radiative rates, thanks to an appropriate transformation of parametric space by simple linear expansion and rotation. We provide evidence that Parity-Time symmetry phase transition path and bound states in continuum (BIC) path represent the natural axis of universal scattering matrix solutions in this parametric coupling-detuning plane and determine the main characteristics of Fano resonance.

The Cousa objective: a long-working distance air objective for multiphoton imaging in vivo.

Multiphoton microscopy can resolve fluorescent structures and dynamics deep in scattering tissue and has transformed neural imaging, but applying this technique in vivo can be limited by the mechanical and optical constraints of conventional objectives. Short working distance objectives can collide with compact surgical windows or other instrumentation and preclude imaging. Here we present an ultra-long working distance (20 mm) air objective called the Cousa objective.

Rapid fluctuations in functional connectivity of cortical networks encode spontaneous behavior.

Experimental work across species has demonstrated that spontaneously generated behaviors are robustly coupled to variations in neural activity within the cerebral cortex. Functional magnetic resonance imaging data suggest that temporal correlations in cortical networks vary across distinct behavioral states, providing for the dynamic reorganization of patterned activity. However, these data generally lack the temporal resolution to establish links between cortical signals and the continuously varying fluctuations in spontaneous behavior observed in awake animals.

Growth Quakes and Stasis Using Iterations of Inflating Complex Random Matrices.

I extend to the case of complex matrices, rather than the case of real matrices as in a prior study, a method of iterating the operation of an "inflating random matrix" onto a state vector to describe complex growing systems. I show that the process also describes in this complex case a punctuated growth with quakes and stasis. I assess that under one such inflation step, the vector will shift to a really different one (quakes) only if the inflated matrix has sufficiently dominant new eigenvectors.

Genes enriched in A/T-ending codons are co-regulated and conserved across mammals.

Codon usage influences gene expression distinctly depending on the cell context. Yet, the importance of codon bias in the simultaneous turnover of specific groups of protein-coding genes remains to be investigated. Here, we find that genes enriched in A/T-ending codons are expressed more coordinately in general and across tissues and development than those enriched in G/C-ending codons.

Using protein-per-mRNA differences among human tissues in codon optimization.

Background: Codon usage and nucleotide composition of coding sequences have profound effects on protein expression. However, while it is recognized that different tissues have distinct tRNA profiles and codon usages in their transcriptomes, the effect of tissue-specific codon optimality on protein synthesis remains elusive.

Results: We leverage existing state-of-the-art transcriptomics and proteomics datasets from the GTEx project and the Human Protein Atlas to compute the protein-to-mRNA ratios of 36 human tissues.

Spatiotemporally heterogeneous coordination of cholinergic and neocortical activity.

Variation in an animal's behavioral state is linked to fluctuations in brain activity and cognitive ability. In the neocortex, state-dependent circuit dynamics may reflect neuromodulatory influences such as that of acetylcholine (ACh). Although early literature suggested that ACh exerts broad, homogeneous control over cortical function, recent evidence indicates potential anatomical and functional segregation of cholinergic signaling.

Review of data processing of functional optical microscopy for neuroscience.

Functional optical imaging in neuroscience is rapidly growing with the development of optical systems and fluorescence indicators. To realize the potential of these massive spatiotemporal datasets for relating neuronal activity to behavior and stimuli and uncovering local circuits in the brain, accurate automated processing is increasingly essential. We cover recent computational developments in the full data processing pipeline of functional optical microscopy for neuroscience data and discuss ongoing and emerging challenges.

Which features of repetitive negative thinking and positive reappraisal predict depression? An in-depth investigation using artificial neural networks with feature selection.

Emotion regulation habits have long been implicated in risk for depression. However, research in this area traditionally adopts an approach that ignores the multifaceted nature of emotion regulation strategies, the clinical heterogeneity of depression, and potential differential relations between emotion regulation features and individual symptoms. To address limitations associated with the dominant aggregate-level approach, this study aimed to identify which features of key emotion regulation strategies are most predictive and when those features are most predictive of individual symptoms of depression across different time lags.

Dynamic compartmental computations in tuft dendrites of layer 5 neurons during motor behavior.

Tuft dendrites of layer 5 pyramidal neurons form specialized compartments important for motor learning and performance, yet their computational capabilities remain unclear. Structural-functional mapping of the tuft tree from the motor cortex during motor tasks revealed two morphologically distinct populations of layer 5 pyramidal tract neurons (PTNs) that exhibit specific tuft computational properties. Early bifurcating and large nexus PTNs showed marked tuft functional compartmentalization, representing different motor variable combinations within and between their two tuft hemi-trees.

Alliance rupture profiles by personality disorder pathology in psychotherapy for depression: Tendencies, development, and timing.

Objective: Clinical and theoretical considerations presume that patients with different personality disorder (PD) clusters will be associated with distinct alliance rupture profiles; however, there is scarce empirical literature examining this. The present study adopted a systematic framework for investigating profiles of alliance ruptures for individuals belonging to each of the three PD clusters.

Method: The sample consisted of 94 patients from a randomized controlled trial for treatment of depression.

From research to rapid response: mass COVID-19 testing by volunteers at the Centre for Genomic Regulation.

The COVID-19 pandemic has posed and is continuously posing enormous societal and health challenges worldwide. The research community has mobilized to develop novel projects to find a cure or a vaccine, as well as to contribute to mass testing, which has been a critical measure to contain the infection in several countries. Through this article, we share our experiences and learnings as a group of volunteers at the Centre for Genomic Regulation (CRG) in Barcelona, Spain.

Translational adaptation of human viruses to the tissues they infect.

Viruses need to hijack the translational machinery of the host cell for a productive infection to happen. However, given the dynamic landscape of tRNA pools among tissues, it is unclear whether different viruses infecting different tissues have adapted their codon usage toward their tropism. Here, we collect the coding sequences of 502 human-infecting viruses and determine that tropism explains changes in codon usage.

Positive role of the long luminescence lifetime of upconversion nanophosphors on resonant surfaces for ultra-compact filter-free bio-assays.

We introduce a compact array fluorescence sensor principle that takes advantage of the long luminescence lifetimes of upconversion nanoparticles (UCNPs) to deploy a filter-free, optics-less contact geometry, advantageous for modern biochemical assays of biomolecules, pollutants or cells. Based on technologically mature CMOS chips for ∼10 kHz technical/scientific imaging, we propose a contact geometry between assayed molecules or cells and a CMOS chip that makes use of only a faceplate or direct contact, employing time-window management to reject the 975 nm excitation light of highly efficient UCNPs. The chip surface is intended to implement, in future devices, a resonant waveguide grating (RWG) to enhance excitation efficiency, aiming at the improvement of upconversion luminescence emission intensity of UCNP deposited atop of such an RWG structure.

Mutation bias within oncogene families is related to proliferation-specific codon usage.

It is well known that in cancer gene families some members are more frequently mutated in tumor samples than their family counterparts. A paradigmatic case of this phenomenon is KRAS from the RAS family. Different explanations have been proposed ranging from differential interaction with other proteins to preferential expression or localization.

NMDAR-Dependent Emergence of Behavioral Representation in Primary Visual Cortex.

Although neocortical sensory areas are generally thought to faithfully represent external stimuli, cortical networks exhibit considerable functional plasticity, allowing them to modify their output to reflect ongoing behavioral demands. We apply longitudinal 2-photon imaging of activity in the primary visual cortex (V1) of mice learning a conditioned eyeblink task to investigate the dynamic representations of task-relevant information. We find that, although all V1 neurons robustly and stably encode visual input, pyramidal cells and parvalbumin-expressing interneurons exhibit experience-dependent emergence of accurate behavioral representations during learning.

Cell-Type-Specific Outcome Representation in the Primary Motor Cortex.

Adaptive movements are critical for animal survival. To guide future actions, the brain monitors various outcomes, including achievement of movement and appetitive goals. The nature of these outcome signals and their neuronal and network realization in the motor cortex (M1), which directs skilled movements, is largely unknown.

Translational efficiency across healthy and tumor tissues is proliferation-related.

Different tissues express genes with particular codon usage and anticodon tRNA repertoires. However, the codon-anticodon co-adaptation in humans is not completely understood, nor is its effect on tissue-specific protein levels. Here, we first validated the accuracy of small RNA-seq for tRNA quantification across five human cell lines.

Systems level expression correlation of Ras GTPase regulators.

Background: Proteins of the ubiquitously expressed core proteome are quantitatively correlated across multiple eukaryotic species. In addition, it was found that many protein paralogues exhibit expression anticorrelation, suggesting that the total level of protein with a given functionality must be kept constant.

Methods: We performed Spearman's rank correlation analyses of gene expression levels for the RAS GTPase subfamily and their regulatory GEF and GAP proteins across tissues and across individuals for each tissue.