Catálogo de publicaciones - revistas

<jats:p>Injecting drug users often seek medical help late in pregnancy and then relinquish their babies to the state. Surprisingly, their drug use is not the major factor.</jats:p>

<jats:p>The Biomedical Center conducts top-notch studies with foreign collaborators, a surprising rarity in Russia to this day.</jats:p>

<jats:p>HIV infection can persist in spite of efficacious antiretroviral therapies. Although incomplete inhibition of viral replication may contribute to this phenomenon, this is largely due to the early establishment of a stable reservoir of latently infected cells. Thus, life-long antiviral therapy may be needed to control HIV. Such therapy is prone to drug resistance and cumulative side effects and is an unbearable financial burden for regions of the world hit hardest by the epidemic. This review discusses our current understanding of HIV persistence and the limitations of potential approaches to eradicate the virus and accordingly pleads for a joint multidisciplinary effort toward two highly related goals: the development of an HIV prophylactic vaccine and the achievement of long-term drug-free remissions in HIV-infected individuals.</jats:p>

<jats:p>Female fireflies are more likely to respond to simulated male flashes that are synchronized than to unsynchronized flashes.</jats:p>

<jats:title>BK Channel Cytoplasmic Domain</jats:title> <jats:p> BK channels are potassium ion channels found on the surface of a variety of cell types that are essential for the regulation of several key physiological processes, including smooth muscle tone and neuronal excitability. BK channels are regulated by both membrane voltage and intracellular Ca <jats:sup>2+</jats:sup> . The channel comprises an integral membrane pore, an integral membrane voltage sensor domain, and a large cytoplasmic region that confers Ca <jats:sup>2+</jats:sup> sensitivity. Now <jats:bold> Yuan <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5988" page="182" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1190414">182</jats:related-article> , published online 27 May; see the Perspective <jats:bold>Weyand and Iwata</jats:bold> ) have determined the crystal structure of the cytoplasmic domain of the human BK channel. Four cytoplasmic regions form a gating ring at the intracellular membrane surface with four Ca <jats:sup>2+</jats:sup> binding sites on the outer perimeter. </jats:p>

<jats:title>Out of the Oort Cloud</jats:title> <jats:p> Long-period comets originate from the Oort cloud, a vast reservoir of icy bodies that surrounds the solar system. These bodies are thought to be remnants from the formation of the solar system. But did they all form in the Sun's protoplanetary disk, or could they have been generated in the protoplanetary disks of other stars in the cluster where the Sun probably formed? <jats:bold> Levison <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5988" page="187" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1187535">187</jats:related-article> , published online 10 June) used detailed numerical simulations to investigate what fraction of comets might transfer from the outer reaches of one stellar system to another. The simulations suggest that a substantial number of comets can be captured through this mechanism, which may explain why the number of bodies in the Oort cloud is larger than models predict. </jats:p>

<jats:title>Separating Under Strain</jats:title> <jats:p> Complex oxides, such as cuprate superconductors and perovskites, often exhibit microscopic phase separation, where two or more phases coexist on the macroscopic scale but are spatially separated on the microscopic scale. <jats:bold> Lai <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5988" page="190" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1189925">190</jats:related-article> ) studied a configuration often found in technological applications, a strained manganite thin film placed on a substrate. Microwave impedance microscopy, which differentiates between conducting and insulating areas on the thin film, allowed visualization of the phase separation as the magnetic field was varied. A network of conducting domains was observed whose orientation and characteristic length scales suggest that the substrate-exerted strain was involved in network formation. </jats:p>

<jats:title>Elucidating Turbulent Flow</jats:title> <jats:p> When needing to mix two fluids rapidly, turbulent flow can be beneficial. However, in most cases, the churning and tumbling motions of a fluid during turbulent flow reduce the efficiency of a device or process. When fluid flows past a solid object, the bulk of the turbulent motion is concentrated at the surface boundary, but it is unclear to what extent these inner motions are influenced by flow far from the boundary. <jats:bold> Marusic <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5988" page="193" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1188765">193</jats:related-article> ; see the Perspective by <jats:bold>Adrian</jats:bold> ) demonstrate a nonlinear connection between inner-layer motions and the large-scale outer-layer motions in wind tunnel experiments. A simple model was able to describe the relationship mathematically while accurately mapping the experimental data. </jats:p>

<jats:title>Nanorod Polymers</jats:title> <jats:p> Nanoparticles and colloids have been used to model crystallization and melting phenomena. <jats:bold> Liu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5988" page="197" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1189457">197</jats:related-article> ) studied the polymerization kinetics of nanoparticles. Functionalized arrowhead nanorods acted as linkable units that joined together in solvent-tuned assembly. The results resembled common processes of chemical polymerization: Growth was controlled kinetically and could be interpreted by formulas for step-growth polymerization and branching. Furthermore, some isomerization phenomena were observed, as was the formation of cyclic “macromolecules.” </jats:p>

<jats:title>Switching Basins</jats:title> <jats:p> Most of the densest, deepest water at the bottom of the oceans comes from two regions, the North Atlantic and the circum-Antarctic. Have other regions been able to produce significant quantities of deep water in the past? For decades, researchers have looked, with limited success, for evidence of deepwater formation in the North Pacific since the time of the Last Glacial Maximum, about 23,000 years ago. <jats:bold> Okazaki <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5988" page="200" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1190612">200</jats:related-article> ) combine published observational evidence from the North Pacific with model simulations to suggest that deep water did form in the North Pacific during the early part of the Last Glacial Termination, between about 17,500 and 15,000 years ago. The switch between deep-water formation in the North Atlantic and the North Pacific is likely to have had an important effect on heat transport and climate. </jats:p>