Catálogo de publicaciones - revistas

<jats:title>A view through a fiber</jats:title> <jats:p> Reconstructing a three-dimensional (3D) image of a scene typically involves sending out pulses of light and timing their return. For endoscope applications in bioimaging or imaging inside difficult-to-reach places inside machines, the typical approach using bulk optics may not be viable. Stellinga <jats:italic>et al</jats:italic> . found that 3D imaging can be achieved using multimode optic fibers. After characterizing the transmission matrix of the fiber, optical pulses can be used to reconstruct 3D images of a number of scenes. Because this approach can use fibers the width of a human hair, the results are promising for miniaturized and minimally invasive 3D endoscopic imaging applications. —ISO </jats:p>

<jats:title>Detecting orbital magnetism</jats:title> <jats:p> Graphene’s electronic structure has been predicted to lead to an unusual orbital response to magnetic fields. However, detecting this orbital magnetism is difficult because it is usually masked by the signal stemming from spins. Vallejo Bustamante <jats:italic>et al</jats:italic> . managed to capture this response by placing two giant magnetoresistance detectors below a sample of graphene sandwiched by layers of hexagonal boron nitride. These detectors picked up a strong diamagnetic response from an undoped sample, consistent with theoretical predictions. The technique may be useful in the investigation of other two-dimensional materials. —JS </jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>

<jats:title>An atlas of cancer-associated T cells</jats:title> <jats:p> The tumor microenvironment contains many different kinds of immune cells, the composition, function, and roles of which are unclear. Using single-cell RNA sequencing of T cells in 21 cancer types from more than 300 patients, Zheng <jats:italic>et al</jats:italic> . identified differences in transcript composition that could be used to catalog different T cell types (see the Perspective by van der Leun and Schumacher). These annotations identified the different roles of specific types of CD4 <jats:sup>+</jats:sup> and CD8 <jats:sup>+</jats:sup> T cells among the different tumor types. Some of these clusters revealed evidence for two developmental paths for T cells, one of which shows a trajectory toward the “exhausted” T cell state, knowledge of which may be useful in developing future cancer immunotherapies. —LMZ </jats:p>

<jats:title>Vaccination and disease</jats:title> <jats:p> The United Kingdom has high rates of vaccination for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exceeding 80% of adults. As immunity wanes and social distancing is relaxed, how are rates of illness and severe disease affected by more infectious variants? Elliott <jats:italic>et al</jats:italic> . used reverse transcription PCR data from the REACT-1 study, which showed exponential transmission as the Alpha variant (B.1.1.7) was replaced by the Delta variant (B.1.617.2). After adjusting for age and other variables, vaccine effectiveness for the new variant averaged 55% in June and July of 2020. Despite the slower growth of the pandemic in the summer, it looks as if increased indoor mixing in the autumn will sustain transmission of the Delta variant despite high levels of adult vaccination. —CA </jats:p>

<jats:title>Giraffe pangenomes</jats:title> <jats:p> Genomes within a species often have a core, conserved component, as well as a variable set of genetic material among individuals or populations that is referred to as a “pangenome.” Inference of the relationships between pangenomes sequenced with short-read technology is often done computationally by mapping the sequences to a reference genome. The computational method affects genome assembly and comparisons, especially in cases of structural variants that are longer than an average sequenced region, for highly polymorphic loci, and for cross-species analyses. Siren <jats:italic>et al</jats:italic> . present a bioinformatic method called Giraffe, which improves mapping pangenomes in polymorphic regions of the genome containing single nucleotide polymorphisms and structural variants with standard computational resources, making large-scale genomic analyses more accessible. —LMZ </jats:p>

<jats:p>The first protein structures were determined by x-ray crystallography in 1957 by John C. Kendrew and Max F. Perutz. As a bioinorganic chemist, I was delighted that the structures were myoglobin and hemoglobin, both heme proteins with big, beautiful iron atoms. It must have been an extraordinary experience to stare at a physical model of the structures and see something that had previously only been imagined. Not long afterward, Christian B. Anfinsen Jr. proposed that the structure of a protein was thermodynamically stable. It seemed possible that the three-dimensional structure of a protein could be predicted based on the sequence of its amino acids. This “protein-folding problem,” as it came to be known, baffled scientists until this year, when the papers we’ve deemed the 2021 Breakthrough of the Year were published.</jats:p>

<jats:p>Breakup of shelf holding back Thwaites Glacier will ramp up sea level rise</jats:p>