CRISPR‐Cas are self‐/nonself‐discriminating systems found in prokaryotic cells. They represent a remarkable example of molecular memory that is hereditarily transmitted. Their discovery can be ...considered as one of the first fruits of the systematic exploration of prokaryotic genomes. Although this genomic feature was serendipitously discovered in molecular biology studies, it was the availability of multiple complete genomes that shed light about their role as a genetic immune system. Here we tell the story of how this discovery originated and was slowly and painstakingly advanced to the point of understating the biological role of what initially was just an odd genomic feature.
Clustered, regularly interspaced short palindromic repeats (CRISPR), present in the genome of archaea and bacteria, are separated by spacer sequences derived from fragments of foreign nucleic acids. CRISPR‐RNA molecules, containing a single spacer, guide CRISPR‐associated (Cas) proteins to spacer‐complementary sequences in invader genomes to cleave a matching target, providing prokaryotes with a unique, heritable, and adaptive immune system.
The chiroptical features of supramolecular polymers formed from N‐heterotriangulenes 1–3 have been investigated by circular dichroism (ECD) and vibrational circular dichroism (VCD) techniques. In ...solution, the CD spectra demonstrate that the helicity of the aggregates depends on only the stereogenic centres located at the peripheral chains. In the gel state, the chiroptical features are conditioned by the point chirality of the stereogenic centres and by the achiral solvent utilised. Sonication of the gels formed in CCl4 reveals both kinetic and thermodynamic phases. These findings reveal the presence of pathway complexity in the gel state triggered by sonication. The described solvent‐induced helical stereomutation demonstrates that the gel state can be utilised as an outstanding benchmark for investigating uncommon chiroptical effects and to explore the rules of chirality transmission.
Twists and turns: The chiroptical features of supramolecular polymers formed from N‐heterotriangulenes 1–3 have been investigated by circular dichroism and vibrational circular dichroism techniques. Solvent‐directed pathway complexity, yielding kinetic or thermodynamic aggregates, is observed for N‐heterotriangulenes 1–3 in the gel state (see figure).
Metaviriomes, the viral genomes present in an environment, have been studied by direct sequencing of the viral DNA or by cloning in small insert libraries. The short reads generated by both ...approaches make it very difficult to assemble and annotate such flexible genomic entities. Many environmental viruses belong to unknown groups or prey on uncultured and little known cellular lineages, and hence might not be present in databases.
Here we have used a different approach, the cloning of viral DNA into fosmids before sequencing, to obtain natural contigs that are close to the size of a viral genome. We have studied a relatively low diversity extreme environment: saturated NaCl brines, which simplifies the analysis and interpretation of the data. Forty-two different viral genomes were retrieved, and some of these were almost complete, and could be tentatively identified as head-tail phages (Caudovirales).
We found a cluster of phage genomes that most likely infect Haloquadratum walsbyi, the square archaeon and major component of the community in these hypersaline habitats. The identity of the prey could be confirmed by the presence of CRISPR spacer sequences shared by the virus and one of the available strain genomes. Other viral clusters detected appeared to prey on the Nanohaloarchaea and on the bacterium Salinibacter ruber, covering most of the diversity of microbes found in this type of environment. This approach appears then as a viable alternative to describe metaviriomes in a much more detailed and reliable way than by the more common approaches based on direct sequencing. An example of transfer of a CRISPR cluster including repeats and spacers was accidentally found supporting the dynamic nature and frequent transfer of this peculiar prokaryotic mechanism of cell protection.
A giant coronary artery aneurysm is an infrequent anomaly encountered as an incidental finding. An even more rare condition is its association with a coronary artery fistula. We report the case of a ...61-year-old woman that combines two of the rarest coronary anomalies: a 70-mm giant circumflex aneurysm with an arteriovenous fistula tract draining to the superior vena cava. Considering the unique display of anatomy, the surgery was guided with 3-dimensional printing technology. Direct fistula occlusion near its outflow union, orifice source closure, aneurysmal sac exclusion, and two coronary artery bypass grafts were surgically performed. The postoperative course was satisfactory.
The gastrocnemius venous system presents different anatomical variants. There have been described four locations of myofascial trigger points (MTrPs) in this muscle. However, no studies have analyzed ...the coincidence between vessels and MTrPs present in the gastrocnemius. Therefore, the main objective was to study the anatomical variability of the venous system by ultrasound and its coincidence with the location of the MTrPs.PURPOSEThe gastrocnemius venous system presents different anatomical variants. There have been described four locations of myofascial trigger points (MTrPs) in this muscle. However, no studies have analyzed the coincidence between vessels and MTrPs present in the gastrocnemius. Therefore, the main objective was to study the anatomical variability of the venous system by ultrasound and its coincidence with the location of the MTrPs.A total of 100 lower limbs were studied. The gastrocnemius vessels were analyzed one by one by sector (medial, central, and lateral), quantifying the number of vessels, their distribution, and the coincidence with MTrPs.METHODSA total of 100 lower limbs were studied. The gastrocnemius vessels were analyzed one by one by sector (medial, central, and lateral), quantifying the number of vessels, their distribution, and the coincidence with MTrPs.All muscle heads showed at least one vessel per section. A large variability was observed, from one to eight vessels per muscle head, with the most frequent number being three in the gastrocnemius medialis and two in the gastrocnemius lateralis. In all cases, the location of the vessels coincided with the MTrPs.RESULTSAll muscle heads showed at least one vessel per section. A large variability was observed, from one to eight vessels per muscle head, with the most frequent number being three in the gastrocnemius medialis and two in the gastrocnemius lateralis. In all cases, the location of the vessels coincided with the MTrPs.The proximal gastrocnemius venous pattern is very variable between subjects in number of vessels and distribution, which has made it impossible to define a "safe" approach window for invasive procedures without ultrasound guidance. The coincidence between the clinical location of MTrPs of the gastrocnemius and the presence of vessels is total.CONCLUSIONSThe proximal gastrocnemius venous pattern is very variable between subjects in number of vessels and distribution, which has made it impossible to define a "safe" approach window for invasive procedures without ultrasound guidance. The coincidence between the clinical location of MTrPs of the gastrocnemius and the presence of vessels is total.
Incidental finding of a giant cardiac lipoma Guevara-Bonilla, Audelio; Valera-Martínez, Francisco J.; Martínez-León, Juan B.
Revista española de cardiología (English ed.),
July 2023, 2023-Jul, 2023-07-00, 20230701, Letnik:
76, Številka:
7
Journal Article
The human brain is arguably the most complex "machine" to ever exist. Its detailed functioning is yet to be fully understood, let alone modelled. Neurological processes have logical signal-processing ...and biophysical aspects, and both affect the brain's structure, functioning and adaptation. Mathematical approaches based on both information and graph theory have been extensively used in an attempt to approximate its biological functioning, along with Artificial Intelligence frameworks inspired by its logical functioning. In this article, an approach to model some aspects of the brain learning and signal processing is presented, mimicking the metastability and backpropagation found in the real brain while also accounting for neuroplasticity. Several simulations are carried out with this model to demonstrate how dynamic neuroplasticity, neural inhibition and neuron migration can reshape the brain's logical connectivity to synchronise signal processing and obtain certain target latencies. This work showcases the importance of dynamic logical and biophysical remodelling in brain plasticity. Combining mathematical (agents, graph theory, topology and backpropagation) and biomedical ingredients (metastability, neuroplasticity and migration), these preliminary results prove complex brain phenomena can be reproduced-under pertinent simplifications-via affordable computations, which can be construed as a starting point for more ambitiously accurate simulations.
Infinite Factorial Unbounded-State Hidden Markov Model Valera, Isabel; Ruiz, Francisco J. R.; Perez-Cruz, Fernando
IEEE transactions on pattern analysis and machine intelligence,
2016-Sept.-1, 2016-09-00, 2016-9-1, 20160901, Letnik:
38, Številka:
9
Journal Article
Recenzirano
There are many scenarios in artificial intelligence, signal processing or medicine, in which a temporal sequence consists of several unknown overlapping independent causes, and we are interested in ...accurately recovering those canonical causes. Factorial hidden Markov models (FHMMs) present the versatility to provide a good fit to these scenarios. However, in some scenarios, the number of causes or the number of states of the FHMM cannot be known or limited a priori. In this paper, we propose an infinite factorial unbounded-state hidden Markov model (IFUHMM), in which the number of parallel hidden Markov models (HMMs) and states in each HMM are potentially unbounded. We rely on a Bayesian nonparametric (BNP) prior over integer-valued matrices, in which the columns represent the Markov chains, the rows the time indexes, and the integers the state for each chain and time instant. First, we extend the existent infinite factorial binary-state HMM to allow for any number of states. Then, we modify this model to allow for an unbounded number of states and derive an MCMC-based inference algorithm that properly deals with the trade-off between the unbounded number of states and chains. We illustrate the performance of our proposed models in the power disaggregation problem.
The brain is the most complex organ in the human body and, as such, its study entails great challenges (methodological, theoretical, etc.). Nonetheless, there is a remarkable amount of studies about ...the consequences of pathological conditions on its development and functioning. This bibliographic review aims to cover mostly findings related to changes in the physical distribution of neurons and their connections—the connectome—both structural and functional, as well as their modelling approaches. It does not intend to offer an extensive description of all conditions affecting the brain; rather, it presents the most common ones. Thus, here, we highlight the need for accurate brain modelling that can subsequently be used to understand brain function and be applied to diagnose, track, and simulate treatments for the most prevalent pathologies affecting the brain.
Modeling systems from collected data faces two main difficulties: the first one concerns the choice of measurable variables that will define the learnt model features, which should be the ones ...concerned by the addressed physics, optimally neither more nor less than the essential ones. The second one is linked to accessibility to data since, generally, only limited parts of the system are accessible to perform measurements. This work revisits some aspects related to the observation, description, and modeling of systems that are only partially accessible and shows that a model can be defined when the loading in unresolved degrees of freedom remains unaltered in the different experiments.
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