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<jats:p>Cardiovascular diseases claim more lives worldwide than any other. Etiologically, the dominant trajectory involves atherosclerosis, a chronic inflammatory process of lipid-rich lesion growth in the vascular wall that can cause life-threatening myocardial infarction (MI). Those who survive MI can develop congestive heart failure, a chronic condition of inadequate pump activity that is frequently fatal. Leukocytes (white blood cells) are important participants at the various stages of cardiovascular disease progression and complication. This Review will discuss leukocyte function in atherosclerosis, MI, and heart failure.</jats:p>

<jats:p>A number of widespread and devastating chronic diseases, including atherosclerosis, type 2 diabetes, and Alzheimer’s disease, have a pathophysiologically important inflammatory component. In these diseases, the precise identity of the inflammatory stimulus is often unknown and, if known, is difficult to remove. Thus, there is interest in therapeutically targeting the inflammatory response. Although there has been success with anti-inflammatory therapy in chronic diseases triggered by primary inflammation dysregulation or autoimmunity, there are considerable limitations. In particular, the inflammatory response is critical for survival. As a result, redundancy, compensatory pathways, and necessity narrow the risk:benefit ratio of anti-inflammatory drugs. However, new advances in understanding inflammatory signaling and its links to resolution pathways, together with new drug development, offer promise in this area of translational biomedical research.</jats:p>

<jats:p>Metabolism and immunity are inextricably linked both to each other and to organism-wide function, allowing mammals to adapt to changes in their internal and external environments. In the modern context of obesogenic diets and lifestyles, however, these adaptive responses can have deleterious consequences. In this Review, we discuss the pleiotropic actions of inflammation and insulin resistance in metabolic homeostasis and disease. An appreciation of the adaptive context in which these responses arose is useful for understanding their pathogenic actions in disease.</jats:p>

<jats:title>Tracking Quantum Evolution</jats:title> <jats:p> The actual process of measuring a quantum system has an effect on the result making the outcome unpredictable. Using a superconducting qubit placed in a microwave cavity, <jats:bold> Hatridge <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="178" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1226897">178</jats:related-article> ) found that a series of partial measurements on a quantum system left the system in a pure state. Looking at the record of the actual measurements allowed the final state of a superconducting-based quantum system to be determined accurately. Such control is crucial for achieving full feedback control of a general quantum system. </jats:p>

<jats:title>Optimizing Carbon Nanotubes</jats:title> <jats:p> Shorter carbon nanotubes are easier to make, but, when assembled into fibers, the resulting fiber properties are much poorer than might be predicted by theory. Conversely, longer carbon nanotubes have much better properties but are harder to process. <jats:bold> Behabtu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="182" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1228061">182</jats:related-article> ) combined the best of both worlds through scalable wet spinning method, in which they dissolved longer carbon nanotubes and then spun them into fibers that showed excellent strength, stiffness, and thermal conductivity. </jats:p>

<jats:title>Mini Mighty Muscle</jats:title> <jats:p> Actuators—or artificial muscles—take electrical or chemical energy and convert it into mechanical force. Typically, actuators made from polymers can show large deformations, but cannot generate a lot of force. <jats:bold> Ma <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="186" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1230262">186</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6116" page="150" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1232733">Kim and Kwon</jats:related-article> </jats:bold> ) describe a polymer composite based on a modified polypyrrole that expands in response to water absorption. The composite was able to generate large stresses and forces, and offered a high work density approaching those of the best conducting polymer electrochemical actuators. Magnetic nanoparticles incorporated into polymer films were used to control the locomotion of the actuator. </jats:p>

<jats:title>Ribosomal Rotaxane?</jats:title> <jats:p> The ribosome is an extraordinarily sophisticated molecular machine, assembling amino acids into proteins based on the precise sequence dictated by messenger RNA. <jats:bold> Lewandowski <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="189" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1229753">189</jats:related-article> ) have now taken a step toward the preparation of a stripped-down synthetic ribosome analog. Their machine comprises a rotaxane—a ring threaded on a rod—in which the ring bears a pendant thiol that can pluck amino acids off the rod; the terminal nitrogen then wraps around to form a peptide bond and liberate the thiol for further reaction. The system was able to link three amino acids in order from the preassembled rod. </jats:p>

<jats:title>Size Affects Shape</jats:title> <jats:p> Porous molecular framework materials can adopt a different phase when guest molecules absorb and uniformly distort the framework. Usually the framework returns to its original shape when the guests desorb. <jats:bold> Sakata <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="193" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1231451">193</jats:related-article> ) noted that because surface stress drives this process, it might be avoided in smaller crystals. Indeed, a flexible porous coordination polymer, [Cu <jats:sub>2</jats:sub> (dicarboxylate) <jats:sub>2</jats:sub> (amine)] <jats:sub> <jats:italic>n</jats:italic> </jats:sub> , could retain the structure induced by guest molecules such as methanol if crystallites were made sufficiently small (submicrometer scale) and did so to a greater degree as the crystallite dimensions decreased. </jats:p>

<jats:title>The Adult Astrocyte Is Different</jats:title> <jats:p> The concept of the tripartite synapse, whereby astrocytes actively modulate the communication between the pre- and postsynaptic site, is widely accepted. The release of gliotransmitters has been linked to release of Ca <jats:sup>2÷</jats:sup> from intracellular stores via the activation of astrocytic metabotropic glutamate receptor 5 (mGluR5) by glutamate spillover from synapses. However, nearly all studies on the tripartite synapse have used brain tissue collected from young individuals. Many receptors undergo changes in expression level during development. <jats:bold> Sun <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="197" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1226740">197</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6116" page="152" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1233208"> <jats:bold>Grosche and Reichenbach</jats:bold> </jats:related-article> ) applied genomic analysis, electron microscopy, and calcium imaging in slices and in vivo to assess the presence and the functionality of mGluR5 and mGluR3 receptors during postnatal development in human and mouse astrocytes. Astrocytic expression of mGluR5 was lost by the third postnatal week in mice and was not present in human cortical astrocytes, which calls into question the viability of the tripartite synapse model for adult synapses. </jats:p>

<jats:title>A Varied Bouquet</jats:title> <jats:p> Pollinators display innate attractions to odor, but can also learn to associate odor with a nectar reward. <jats:bold> Riffell <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="200" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1225483">200</jats:related-article> , published online 6 December; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6116" page="151" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1232930">Knaden and Hansson</jats:related-article> </jats:bold> ) characterized the odor profile for flowers to which hawkmoths are innately attracted and found that the majority contain a distinct chemical profile, which is uniquely represented on their olfactory lobe. The moths could also be trained to associate nonattractive odors with a reward and thus learn novel odor attractions. Though learning altered neurons within the antennal lobe, the innate preferences were not changed. </jats:p>