Catálogo de publicaciones - revistas

<jats:p> Ravishankar <jats:italic>et al</jats:italic> . claimed that drive-level capacitance profiling (DLCP) cannot resolve trap density in perovskites of given thickness. We point out that the trap densities derived by DLCP are from the differential capacitance at different frequencies; thus, the background charges caused by diffusion and geometry capacitance have been subtracted. Even for the nondifferential doping analysis, the contribution from diffusion capacitance is negligible and that from geometry capacitance is excluded. </jats:p>

<jats:title>Zoning in on liver growth</jats:title> <jats:p> For organ homeostasis or regrowth after injury or disease, one or more stem cell populations is needed to rebuild lost tissue. There is considerable debate about the source of new cells in the liver. Two groups now identify the source of new hepatocytes (see the Perspective by Andersson). Although the liver may seem to lack major variation across its structure, its lobule is organized into concentric zones where hepatocytes express different metabolic enzymes. Wei <jats:italic>et al.</jats:italic> sought to systematically define the source of new liver cells by comparing 14 fate-mapping mice that label different liver cell types. They found that different regions of the liver lobule exhibit differences in hepatocyte turnover, with zone 2 representing a primary source of new hepatocytes during homeostasis and regeneration. Similarly, He <jats:italic>et al.</jats:italic> designed a genetic approach to record cell proliferation in vivo with high spatial and temporal resolution to enable continuous recording of proliferative events of any specific cell type at the whole-cell population level. Using this method, they identified zone 2 as having the highest proliferative activity and contributing the most to liver regrowth. These findings have implications for the cellular basis of chronic disease pathogenesis, cancer development, and regenerative medicine strategies. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.abb1625">eabb1625</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc4346">eabc4346</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6532" page="887" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abg4864">887</jats:related-article> </jats:p>

<jats:title>Zoning in on liver growth</jats:title> <jats:p> For organ homeostasis or regrowth after injury or disease, one or more stem cell populations is needed to rebuild lost tissue. There is considerable debate about the source of new cells in the liver. Two groups now identify the source of new hepatocytes (see the Perspective by Andersson). Although the liver may seem to lack major variation across its structure, its lobule is organized into concentric zones where hepatocytes express different metabolic enzymes. Wei <jats:italic>et al.</jats:italic> sought to systematically define the source of new liver cells by comparing 14 fate-mapping mice that label different liver cell types. They found that different regions of the liver lobule exhibit differences in hepatocyte turnover, with zone 2 representing a primary source of new hepatocytes during homeostasis and regeneration. Similarly, He <jats:italic>et al.</jats:italic> designed a genetic approach to record cell proliferation in vivo with high spatial and temporal resolution to enable continuous recording of proliferative events of any specific cell type at the whole-cell population level. Using this method, they identified zone 2 as having the highest proliferative activity and contributing the most to liver regrowth. These findings have implications for the cellular basis of chronic disease pathogenesis, cancer development, and regenerative medicine strategies. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.abb1625">eabb1625</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc4346">eabc4346</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6532" page="887" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abg4864">887</jats:related-article> </jats:p>

<jats:title>The many faces of tau</jats:title> <jats:p> The protein tau is implicated in several brain disorders, including Alzheimer's disease, suggesting that it could be a target of therapeutics. However, because it is unclear how the pleiotropic roles of tau lead to neural pathology in different brain diseases, drug development remains challenging. Chang <jats:italic>et al.</jats:italic> review the possible mechanisms of tau in brain diseases and possible paths forward to improving research and drug development. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.abb8255">eabb8255</jats:related-article> </jats:p>

<jats:title>Following cancer through the body</jats:title> <jats:p> The heterogeneity of mammalian tumors has been well documented, but it remains unknown how differences between individual cells lead to metastasis and spread throughout the body. Quinn <jats:italic>et al.</jats:italic> created a Cas9-based lineage tracer and used single-cell sequencing to generate phylogenies and follow the movement of metastatic human cancer cells implanted in the lung of a mouse xenograph model. Using this model, they found that within the same cell line, cancer cells exhibited diverse metastatic phenotypes. These subclones exhibited differential gene expression profiles, some of which were previously associated with metastasis. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.abc1944">eabc1944</jats:related-article> </jats:p>

<jats:title>Visualizing the 3D genome in situ</jats:title> <jats:p> The conformation of the genome within the cell changes depending on cell state, such that being able to visualize genome structure can identify cis and trans interactions among regulatory genetic elements. Payne <jats:italic>et al.</jats:italic> have developed an unbiased genome-sequencing technique in single cells in situ that can infer the chromatin structure by imaging. They were able to identify sequences at subnuclei locations to analyze the proximity relationships among genetic elements within and across chromosomes in single cells. Using this technique, they could detect chromosome territories and distinctions between different types of repetitive sequences and chromosomal features. This method can map and image genomic coordinates with submicrometer resolution in intact single cells. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aay3446">eaay3446</jats:related-article> </jats:p>

<jats:title>A single sugar makes all the difference</jats:title> <jats:p> Antibodies are divided into several classes based on their nonvariable tail (Fc) domains. These regions interact with disparate immune cell receptors and complement proteins to help instruct distinct immune responses. The Fc domain of immunoglobulin G (IgG) antibodies contains a conserved N-linked glycan at position 297. However, the particular glycan used at this position is highly variable. IgG lacking core fucosylation at this position initiates enhanced antibody-dependent cellular cytotoxicity by increased affinity to the Fc receptor FcRIIIa. Larsen <jats:italic>et al.</jats:italic> report that COVID-19 patients with severe symptoms have increased levels of anti–severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG afucosylation compared with patients with mild disease. These findings suggest that treatment of COVID-19 patients with fucosylated anti–SARS-CoV-2 antibodies may circumvent pathologies associated with severe COVID-19. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.abc8378">eabc8378</jats:related-article> </jats:p>

<jats:p>Less than a month after his inauguration, U.S. President Biden moved to reverse policies that have deterred foreign students and high-skilled workers from coming to the United States. This is good news. The exchange of culture and knowledge drives innovation, which in turn builds the nation's economy and competitiveness on a global scale. But some countries, especially China, continue to present a dilemma when it comes to national security. In trying to strike a balance between preserving a culture of openness and protecting U.S. research, missteps can occur—and that can be detrimental to U.S. science.</jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>Newly arrived Mars rover will probe rocks to reveal how wet planet was—and for how long.</jats:p>