Catálogo de publicaciones - revistas

<jats:title>Weyl physics emerges in the laboratory</jats:title> <jats:p> Weyl fermions—massless particles with half-integer spin—were once mistakenly thought to describe neutrinos. Although not yet observed among elementary particles, Weyl fermions may exist as collective excitations in so-called Weyl semimetals. These materials have an unusual band structure in which the linearly dispersing valence and conduction bands meet at discrete “Weyl points.” Xu <jats:italic>et al.</jats:italic> used photoemission spectroscopy to identify TaAs as a Weyl semimetal capable of hosting Weyl fermions. In a complementary study, Lu <jats:italic>et al.</jats:italic> detected the characteristic Weyl points in a photonic crystal. The observation of Weyl physics may enable the discovery of exotic fundamental phenomena. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="613" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa9297">613</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="622" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa9273">622</jats:related-article> </jats:p>

<jats:title>Making better contacts</jats:title> <jats:p> A key issue in fabricating transistors is making a good electrical contact to the semiconductor gate material. For two-dimensional materials, one route is through a phase transition that converts a hexagonally packed semiconductor phase into a distorted octahedrally packed metallic phase. Cho <jats:italic>et al.</jats:italic> show that laser heating of molybdenum telluride (MoTe <jats:sub>2</jats:sub> ) achieves this conversion through the creation of Te vacancies. The phase transition improves charge carrier mobility while maintaining the low resistance necessary for improved transistor function. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="625" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab3175">625</jats:related-article> </jats:p>

<jats:title>Keeping it sticky when wet</jats:title> <jats:p> Some biological molecules are remarkably sticky, even to surfaces submerged in water. Mussel adhesion, for example, is based on the overproduction of dihydroxyphenylalanine (DOPA) and proteins with a high abundance of cationic amine residues such as lysine. Using bacterial iron chelators consisting of paired DOPA and lysine groups as analogs for the mussel proteins, Maier <jats:italic>et al.</jats:italic> show that these two functional groups synergistically enhance interfacial adhesion (see the Perspective by Wilker). The lysine appears to displace hydrated cations from the surface, thus giving a dry patch for better adhesion. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="628" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab0556">628</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="582" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac8174">582</jats:related-article> </jats:p>

<jats:title>Improving electron harvesting</jats:title> <jats:p> Small metal nanostructures generate electrons from light by creating surface plasmons, which can transfer “hot electrons” to a semiconductor. The efficiency of this process, however, is often low because of electron-electron scattering. Wu <jats:italic>et al.</jats:italic> demonstrate a pathway that allows the plasmon to directly excite an electron in a strongly coupled semiconductor acceptor (see the Perspective by Kale). Cadmiun selenide nanorods bearing gold nanoparticles on their ends strongly damped plasmons via interfacial electron transfer with a quantum efficiency exceeding 24%. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="632" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac5443">632</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="587" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac8522">587</jats:related-article> </jats:p>

<jats:title>Testing hypotheses privately</jats:title> <jats:p> Large data sets offer a vast scope for testing already-formulated ideas and exploring new ones. Unfortunately, researchers who attempt to do both on the same data set run the risk of making false discoveries, even when testing and exploration are carried out on distinct subsets of data. Based on ideas drawn from differential privacy, Dwork <jats:italic>et al.</jats:italic> now provide a theoretical solution. Ideas are tested against aggregate information, whereas individual data set components remain confidential. Preserving that privacy also preserves statistical inference validity. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="636" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa9375">636</jats:related-article> </jats:p>

<jats:title>Deltas are growing centers of risk</jats:title> <jats:p> Population growth, urbanization, and rising sea levels are placing populations living in delta regions under increased risk. The future resiliency and potential for adaptation by these populations depend on a number of socioeconomic and geophysical factors. Tessler <jats:italic>et al.</jats:italic> examined 48 deltas from around the globe to assess changes in regional vulnerability (see the Perspective by Temmerman). Some deltas in countries with a high gross domestic product will be initially more resilient to these changes, because they can perform expensive maintenance on infrastructure. However, short-term policies will become unsustainable if unaccompanied by long-term investments in all delta regions. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="638" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab3574">638</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="588" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac8312">588</jats:related-article> </jats:p>

<jats:title>B cells have a need for speed</jats:title> <jats:p> High-affinity antibodies provide long-lasting protective immunity against many infections. Generating such antibodies requires help, in the form of T cells, which interact with antibody-producing B cells. As B cells proliferate and mutate their antibody genes, T cells select the cells producing high-affinity antibodies. Gitlin <jats:italic>et al.</jats:italic> show in mice that B cells that receive T cell help transit through the cell cycle more quickly by increasing the speed at which replication forks progress. Such a rapid cell cycle transition gives high-affinity B cells a selective advantage. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="643" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac4919">643</jats:related-article> </jats:p>

<jats:title>Silencing neurons using optogenetics</jats:title> <jats:p> Rhodopsin light-sensitive ion channels from green algae provide a powerful tool to control neuronal circuits. Rhodopsin cation channels effectively depolarize neurons and cause the firing of short-lived electrical membrane potentials. Govorunova <jats:italic>et al.</jats:italic> describe algal channels that do the opposite; that is, they hyperpolarize or silence particular neurons (see the Perspective by Berndt and Deisseroth). These cation channels provide greater light sensitivity than that of existing hyperpolarizing light-activated channels, operate rapidly, and selectively conduct only anions. This approach is an ideal complement to the widely used technique of creating light-sensitive neurons through the expression of rhodopsin cation channels. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="647" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa7484">647</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="590" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac7889">590</jats:related-article> </jats:p>

<jats:title>Mechanistic surprise in ALS-FTD</jats:title> <jats:p> Intense efforts have focused on identifying therapeutic targets for misfolded proteins that cause amyotrophic lateral sclerosis and frontotemporal dementia (ALS-FTD). Ling <jats:italic>et al.</jats:italic> show that the main culprit of proteinopathy, TDP-43, acts as a splicing suppressor of nonconserved cryptic exons. These exons often disrupt messenger RNA translation and promote nonsense-mediated decay. When TDP-43 was depleted in cells, a set of nonconserved cryptic exons spliced into target RNAs, leading to down-regulation of corresponding proteins critical for cellular function. Repression of cryptic exons prevented cell death in TDP-43–null cells. Because brains of ALS-FTD cases showed evidence of missplicing of cryptic exons, failure in these regions may underlie TDP-43 proteinopathy. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="650" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab0983">650</jats:related-article> </jats:p>

<jats:p> This webinar is the fourth in a series focusing on the cancer pathways that support tumor development, the emerging research in identifying and targeting these pathways, and innovations in the development of increasingly effective cancer therapy options. Recent advances in our understanding of cancer have revealed that the disease cannot be understood through simple analysis of genetic mutations within the cancerous cells. Instead, tumors should be considered as complex tissues in which the cancer cells communicate directly and indirectly with the surrounding cellular microenvironment and evolve traits that promote their own survival. In this webinar we will explore how aberrant changes in epigenetic modification can affect the expression of key genes and contribute to the pathological progression of cancer. <jats:list list-type="bullet"> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://webinar.sciencemag.org/webinar/archive/part-4-targeting-cancer-pathways">View the Webinar</jats:ext-link> </jats:p> </jats:list-item> </jats:list> </jats:p>