编译|李言

Science, 14 FEB 2025, VOL 387, ISSUE 6735

《科学》2025年2月14日，第387卷，6735期

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医学Medicine

Thalamic opioids from POMC satiety neurons switch on sugar appetite

POMC神经元的丘脑阿片类物质调控嗜甜水平

▲ 作者：MARIELLE MINèRE, HANNAH WILHELMS et al.

▲链接：

https://www.science.org/doi/10.1126/science.adp1510

▲摘要：

即使在餐后吃饱的情况下，人们也很容易摄入高糖食物。尽管对美味食物的奖励驱动会激发过度进食，但在饱腹状态下对甜食有偏好的神经生物学机制仍不明确。

下丘脑前阿片黑皮质素（POMC）神经元是饱腹感的主要调节者，因为它们通过兴奋性黑皮质素神经肽减少食物摄入。我们发现POMC神经元不仅在进食条件下促进饱腹感，同时开启了对甜食的食欲，导致过度进食。

POMC神经元向室旁丘脑的投射通过μ-阿片受体信号选择性地抑制了突触后神经元。这一阿片回路在甜食的摄入过程中被强烈激活，在饱腹状态下尤为显著。相应地，抑制其活动减少了饱腹小鼠对高糖饮食的摄入。

▲ Abstract：

High sugar–containing foods are readily consumed, even after meals and beyond fullness sensation (e.g., as desserts). Although reward-driven processing of palatable foods can promote overeating, the neurobiological mechanisms that underlie the selective appetite for sugar in states of satiety remain unclear. Hypothalamic pro-opiomelanocortin (POMC) neurons are principal regulators of satiety because they decrease food intake through excitatory melanocortin neuropeptides. We discovered that POMC neurons not only promote satiety in fed conditions but concomitantly switch on sugar appetite, which drives overconsumption. POMC neuron projections to the paraventricular thalamus selectively inhibited postsynaptic neurons through mu-opioid receptor signaling. This opioid circuit was strongly activated during sugar consumption, which was most notable in satiety states. Correspondingly, inhibiting its activity diminished high-sugar diet intake in sated mice.

材料科学Materials Science

Ultrastable supported oxygen evolution electrocatalyst formed by ripening-induced embedding

熟化诱导嵌入形成的超稳定析氧反应电催化剂

▲ 作者：WENJUAN SHI, TONGHAO SHEN et al.

▲链接：

https://www.science.org/doi/10.1126/science.adr3149

▲摘要：

在此，我们提出一种能将铱催化剂稳固地嵌入氧化铈载体中的成熟诱导嵌入策略。低温电子断层扫描和全原子动力学蒙特卡罗模拟揭示了通过超声调节载体生长速率与铱成核速率的同步对于成功合成至关重要。

使用这种催化剂的质子交换膜水电解池（PEMWE）在每平方厘米3安培的电流密度下实现了1.72伏的电池电压，而铱的负载量仅为每平方厘米0.3毫克，经过6000小时的加速老化测试，其电压退化率为每小时1.33微伏。

▲ Abstract：

Here we present a ripening-induced embedding strategy that securely embeds the Ir catalyst in a cerium oxide support. Cryogenic electron tomography and all-atom kinetic Monte Carlo simulations reveal that synchronizing the growth rate of the support with the nucleation rate of Ir, regulated by sonication, is pivotal for successful synthesis. A PEMWE using this catalyst achieves a cell voltage of 1.72 volts at a current density of 3 amperes per square centimeter with an Ir loading of just 0.3 milligrams per square centimeter and a voltage degradation rate of 1.33 microvolts per hour, as demonstrated by a 6000-hour accelerated aging test.

化学Chemistry

Thermal catalytic reforming for hydrogen production with zero CO₂ emission

二氧化碳零排放的热催化重整制氢技术

▲ 作者：MI PENG, YUZHEN GE et al.

▲链接：

https://www.science.org/doi/10.1126/science.adt0682

▲摘要：

碳中性氢气生产对于未来化学工业至关重要。我们展示了一种新的热催化途径，用于将乙醇部分重整为氢气和乙酸，且几乎不产生二氧化碳排放。这一反应通过一种催化剂实现。

该催化剂含有高密度的原子级Pt1和Ir1物种，负载在反应性α-碳化钼基底上，在270°C下实现了每小时每克催化剂331.3毫摩尔氢气的产率和84.5%的乙酸选择性，因此与标准重整相比更加节能。对乙醇部分重整的技术经济分析展示了在工业规模上潜在的盈利能力，为生产氢气和乙酸提供了大幅减少二氧化碳排放的机会。

▲ Abstract：

Carbon-neutral hydrogen production is of key importance for the chemical industry of the future. We demonstrate a new thermal catalytic route for the partial reforming of ethanol into hydrogen and acetic acid with near-zero carbon dioxide emissions. This reaction is enabled by a catalyst containing a high density of atomic Pt1 and Ir1 species supported on a reactive alpha-molybdenum carbide substrate, achieving a hydrogen production rate of 331.3 millimoles of hydrogen per gram catalyst per hour and an acetic acid selectivity of 84.5% at 270°C, and is therefore more energy-efficient compared with standard reforming. Techno-economic analysis of partial ethanol reforming demonstrates the potential profitability for operation at an industrial scale, presenting the opportunity to produce hydrogen and acetic acid with a substantially reduced carbon dioxide footprint.

动物学Zoology

Elephant seals as ecosystem sentinels for the northeast Pacific Ocean twilight zone

象海豹是东北太平洋暮光带生态系统哨兵

▲ 作者：ROXANNE S. BELTRAN, ALLISON R. PAYNE et al.

▲链接：

https://www.science.org/doi/10.1126/science.adp2244

▲摘要：

开阔海洋的暮光带拥有全球大部分的鱼类生物量，但由于难以大规模测量次表层生态系统过程，人们对这一区域的情况知之甚少。

我们证明了一种广泛分布的肉食性动物——北方象海豹——可以成为暮光带的生态系统哨兵。我们将海洋盆地尺度的觅食成功与海洋学指数联系起来，以估算过去五十年及未来暮光带鱼类的丰度。

我们发现，母体觅食成功的小幅变化会放大为后代体重的较大变化，并造成第一年存活率和补充量的巨大差异。恶化的海洋学条件可能会使捕食者种群轨迹从目前的增长转变为急剧下降。作为海洋的整合者，广泛分布的捕食者可以揭示未来人为变化对开阔海洋生态系统的影响。

▲ Abstract：

The open ocean twilight zone holds most of the global fish biomass but is poorly understood owing to difficulties of measuring subsurface ecosystem processes at scale. We demonstrate that a wide-ranging carnivore—the northern elephant seal—can serve as an ecosystem sentinel for the twilight zone. We link ocean basin–scale foraging success with oceanographic indices to estimate twilight zone fish abundance five decades into the past, and into the future. We discovered that a small variation in maternal foraging success amplified into larger changes in offspring body mass and enormous variation in first-year survival and recruitment. Worsening oceanographic conditions could shift predator population trajectories from current growth to sharp declines. As ocean integrators, wide-ranging predators could reveal impacts of future anthropogenic change on open ocean ecosystems.

地球科学Earth Science

Depth-dependent seismic sensing of groundwater recovery from the atmospheric-river storms of 2023

对2023年大气层河流风暴后地下水恢复的深度依赖性地震传感

▲ 作者：SHUJUAN MAO, WILLIAM L. ELLSWORTH et al.

▲链接：

https://www.science.org/doi/10.1126/science.adr6139

▲摘要：

2023年初，一系列强烈的大气层河流风暴缓解了加利福尼亚州的历史性干旱，然而人们对地下水恢复的时空范围仍然知之甚少。

我们利用地震环境场干涉测量法追踪了大洛杉矶地区二十年来地下水的变迁。所得到的地震水文图揭示了地下水和地表水干旱的明显表现：尽管在2023年的雨季中，地表和近地表水储存几乎完全恢复，但自2006年以来流失的地下水仅有约25%得到补充。

在十年尺度上，我们发现50米深度以下的含水层存在显著枯竭，仅有有限的风暴相关恢复。我们的分析强调了使用高分辨率工具如地震传感来监测深层含水层，以更全面地评估总水亏缺的必要性。

▲ Abstract：

In early 2023, a series of intense atmospheric-river storms eased California’s historic drought, yet the spatiotemporal extent of groundwater recovery remains poorly understood. We tracked two-decadal changes in groundwater in Greater Los Angeles using seismic ambient-field interferometry. The derived seismic hydrographs reveal distinct expressions of groundwater and surficial water droughts: Whereas surface and near-surface water storage nearly fully recovered in the epic wet season of 2023, only about 25% of the groundwater lost since 2006 was restored. On a decadal scale, we find substantial depletion in aquifers below 50-meter depth, with only limited storm-related recovery. Our analysis underscores the need to monitor deep aquifers for a more complete assessment of total water deficits, using high-resolution tools such as seismic sensing.

Variability of flowing stream network length across the US

美国流动溪流网络长度的变化

▲ 作者：JEFF P. PRANCEVIC, HANSJ?RG SEYBOLD, AND JAMES W. KIRCHNER

▲链接：

https://www.science.org/doi/10.1126/science.ado2860

▲摘要：

排水网络中流动溪流的总长度会随着地表变得湿润或干燥，相应变长或缩短。然而，直接测量溪流网络变化的研究仅限于少数小型排水流域。

我们利用测量的流量分布和基于地形的估算，评估了美国本土14765个已测量流域的溪流网络长度变化。这些估算反映了每个溪流网络对景观湿度变化的敏感性（网络的弹性）。

我们发现，美国溪流网络在年度高流量条件下的中位长度是年度低流量条件下的五倍。溪流网络在某些地区比其他地区更具动态性，这主要是由于各地区水文气候学的差异以及网络对水文气候强迫的弹性反应不同所致。

▲ Abstract：

The aggregate length of flowing streams in a drainage network lengthens and shortens as landscapes become wetter and drier. However, direct measurements of stream network variability have been limited to a handful of small drainage basins. We estimated the variability of stream network length for 14,765 gauged basins across the contiguous United States using measured streamflow distributions and topography-based estimates of how sensitive each stream network is to changing landscape wetness (the network’s elasticity). We find that the median US stream network is five times longer during annual high-flow conditions than during annual low-flow conditions. Stream networks are more dynamic in some regions than in others, driven by regional differences in both hydroclimatology and the networks’ elasticity in response to hydroclimatic forcing.