编译|李言
Science, 6 SEP 2024, Volume 385 Issue 6713
《科学》2024年9月6日,第385卷,6713期
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物理学Physics
Achieving optical transparency in live animals with absorbing molecules
通过吸收分子实现活体动物的光学透明
▲ 作者:ZIHAO OU, YI-SHIOU DUH et al.
▲ 链接:https://www.science.org/doi/10.1126/science.adm6869
▲ 摘要:在此。我们报告一反直觉的观察,即强吸收分子可以在活体动物中实现光学透明。我们探索了这一观察背后的物理原理,发现当强吸收分子溶解在水中时,它们可以通过Kramers-Kronig关系改变水介质的折射率,以匹配高折射率组织成分(如脂类)的折射率。
我们已经证明,我们的直接方法可以可逆地使活体小鼠身体透明,从而使大范围的深层结构和活动变得可视化。这项研究表明,寻找高性能光学清除剂应该集中在强吸收分子上。
▲ Abstract:We report the counterintuitive observation that strongly absorbing molecules can achieve optical transparency in live animals. We explored the physics behind this observation and found that when strongly absorbing molecules dissolve in water, they can modify the refractive index of the aqueous medium through the Kramers-Kronig relations to match that of high-index tissue components such as lipids. We have demonstrated that our straightforward approach can reversibly render a live mouse body transparent to allow visualization of a wide range of deep-seated structures and activities. This work suggests that the search for high-performance optical clearing agents should focus on strongly absorbing molecules.
Phantom energy in the nonlinear response of a quantum many-body scar state
量子多体疤痕态非线性响应中的幽灵能量
▲ 作者:KANGNING YANG, YICHENG ZHANG et al.
▲ 链接:https://www.science.org/doi/10.1126/science.adk8978
▲摘要:在这项研究中,我们使用具有吸引相互作用的镝气体来制造疤痕状态,这些状态足够稳定,可以在保持其特性的同时被驱动到强非线性状态。我们测量了淬灭约束势后,动能和总能量的变化。
尽管裸相互作用是有吸引力的,但原子的行为似乎是相互排斥的:它们的动能随着气体被压缩而反常地减少。缺失的“幽灵”能量是通过将我们的实验结果与广义流体力学计算相比较来进行基准测试。我们提供的证据表明,缺失的动能是由未被检测到的高动量原子携带的。
▲ Abstract:In this study, we used attractively interacting dysprosium gases to create scar states that are stable enough to be driven into a strongly nonlinear regime while retaining their character. We measured how the kinetic and total energies evolve after quenching the confining potential. Although the bare interactions are attractive, the atoms behave as if they repel each other: Their kinetic energy paradoxically decreases as the gas is compressed. The missing “phantom” energy is quantified by benchmarking our experimental results against generalized hydrodynamics calculations. We present evidence that the missing kinetic energy is carried by undetected, very high momentum atoms.
天文学Astronomy
Returned samples indicate volcanism on the Moon 120 million years ago
带回的样本表明1.2亿年前月球上有火山活动
▲ 作者:BI-WEN WANG, QIAN W. L. ZHANG et al.
▲ 链接:https://www.science.org/doi/10.1126/science.adk6635
▲摘要:我们研究了嫦娥五号收集的月球土壤样品中的约3000个玻璃珠,并根据它们的质地、化学成分和硫同位素确定了其中3个发源于火山活动。3个火山玻璃珠的铀铅测年表明它们形成于1.2(±0.15)亿年前。这些火山玻璃珠中稀土元素和钍元素的丰度较高,表明这种近代火山活动可能与岩浆地幔源局部富集生热元素有关。
▲ Abstract:We investigated ~3000 glass beads in lunar soil samples collected by the Chang’e-5 mission and identified three as having a volcanic origin on the basis of their textures, chemical compositions, and sulfur isotopes. Uranium-lead dating of the three volcanic glass beads shows that they formed 123 ± 15 million years ago. We measured high abundances of rare earth elements and thorium in these volcanic glass beads, which could indicate that such recent volcanism was related to local enrichment of heat-generating elements in the mantle sources of the magma.
地球科学Earth Science
The economic impacts of ecosystem disruptions: Costs from substituting biological pest control
生态系统被破坏的经济影响:替代生物虫害防治的成本
▲ 作者:EYAL G. FRANK
▲ 链接:https://www.science.org/doi/10.1126/science.adg0344
▲摘要:生物多样性损失正在加速,但我们对这些生态系统的破坏如何影响人类福祉知之甚少。生态学家记录了蝙蝠作为昆虫的天然捕食者的重要性,以及在野生动物疾病出现后它们的数量减少,导致生物害虫控制的潜在下降。
在这项工作中,我研究物种相互作用如何延伸到生态系统之外,并影响农业和人类健康。我发现农民通过增加31.1%的杀虫剂使用量来补偿蝙蝠数量的减少。杀虫剂的补偿性增加对健康产生了不利影响——在发生蝙蝠死亡的地区,婴儿死亡率上升了7.9%。这些发现为之前关于生态系统破坏如何产生有意义的社会成本的理论预测提供了验证。
▲ Abstract:Biodiversity loss is accelerating, yet we know little about how these ecosystem disruptions affect human well-being. Ecologists have documented both the importance of bats as natural predators of insects as well as their population declines after the emergence of a wildlife disease, resulting in a potential decline in biological pest control. In this work, I study how species interactions can extend beyond an ecosystem and affect agriculture and human health. I find that farmers compensated for bat decline by increasing their insecticide use by 31.1%. The compensatory increase in insecticide use by farmers adversely affected health—human infant mortality increased by 7.9% in the counties that experienced bat die-offs. These findings provide empirical validation to previous theoretical predictions about how ecosystem disruptions can have meaningful social costs.
动物学Zoology
Spatial cognitive ability is associated with longevity in food-caching chickadees
储存食物的山雀的寿命与空间认知能力有关
▲ 作者:JOSEPH F. WELKLIN, BENJAMIN R. SONNENBERG et al.
▲ 链接:https://www.science.org/doi/10.1126/science.adn5633
▲摘要:我们提出的直接证据表明,个体认知能力的差异与贮藏食物的野生鸟类的寿命差异相关。我们测量了227只山雀的空间认知能力,并跟踪了它们在自然环境中的寿命,发现具有更好的空间学习和记忆能力的个体寿命更长。这些结果证实,增强的认知能力可能与野生动物的寿命长度有关,并且增强认知能力可能导致寿命延长。
▲ Abstract:We present direct evidence that individual variation in cognitive abilities is associated with differences in life span in a wild food caching bird. We measured the spatial cognitive abilities and tracked the life span of 227 mountain chickadees (Poecile gambeli) in their natural environment and found that individuals with better spatial learning and memory abilities involved in food caching lived longer. These results confirm that enhanced cognitive abilities can be associated with longer life in wild animals and that selection on cognitive abilities can lead to increased life span.
生物学Biology
Organizing the coactivity structure of the hippocampus from robust to flexible memory
组织海马体从稳健记忆到灵活记忆的协同活动结构
▲ 作者:GIUSEPPE P. GAVA, LAURA LEFèVRE et al.
▲ 链接:https://www.science.org/doi/10.1126/science.adk9611
▲ 摘要:在此,我们报告获得稳健(食物环境)记忆限制了小鼠海马在高度相关的峰值序列的群体活动空间内,从而阻止了随后灵活(物体定位)记忆的计算。这种紧密相关的结构是在重复的助记经验中形成的,逐渐将CA1层金字塔状浅层的神经元与整个群体的活动耦合起来。
应用海马体θ驱动的闭环光遗传抑制来减轻(食物—环境)记忆形成过程中的神经元募集,放松了海马体协同活动的拓扑限制,并恢复了随后的灵活(物体定位)记忆。
▲ Abstract:We report that acquiring a robust (food-context) memory constrains the mouse hippocampus within a population activity space of highly correlated spike trains that prevents subsequent computation of a flexible (object-location) memory. This densely correlated firing structure developed over repeated mnemonic experience, gradually coupling neurons in the superficial sublayer of the CA1 stratum pyramidale to whole-population activity. Applying hippocampal theta-driven closed-loop optogenetic suppression to mitigate this neuronal recruitment during (food-context) memory formation relaxed the topological constraint on hippocampal coactivity and restored subsequent flexible (object-location) memory.
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