编译 | 李言

Science,迷信 18 AUG 2023, Volume 381 Issue 6659

《迷信》2022年8月18日，第381卷 ，出书6659期

?周论

生物物理学Biophysics

Alcanivorax borkumensis biofilms enhance oil degradation by interfacial tubulation

泊库岛食烷菌生物膜经由界面管化增长煤油降解

▲ 作者 ：M. PRASAD, N. OBANA et al.

▲ 链接：https://www.science.org/doi/full/10.1126/science.adf3345

▲ 摘要：

在破费烷烃的历程中，泊库岛食烷菌会在油滴周围组成生物膜，文导但这在降解历程中所起的迷信熏染尚不清晰。

咱们发现了生物膜形态的出书变更取决于对于煤油破费的顺应
：持久的吐露导致树突状生物膜的泛起，经由界面的周论管状影响优化了煤油破费
。原位微流体跟踪使咱们可能将管状与界面细胞有序中的文导部份缺陷分割起来。

咱们演示了经由运用限度来定位缺陷来操作液滴变形 ，迷信从而使患上液滴发生突出。出书咱们开拓了一个模子来声名生物膜形态
，周论将微管化与界面张力飞腾以及细胞疏水性削减分割起来
。文导

▲ Abstract：

During the consumption of alkanes,迷信 Alcanivorax borkumensis will form a biofilm around an oil droplet, but the role this plays during degradation remains unclear. We identified a shift in biofilm morphology that depends on adaptation to oil consumption: Longer exposure leads to the appearance of dendritic biofilms optimized for oil consumption effected through tubulation of the interface. In situ microfluidic tracking enabled us to correlate tubulation to localized defects in the interfacial cell ordering. We demonstrate control over droplet deformation by using confinement to position defects, inducing dimpling in the droplets. We developed a model that elucidates biofilm morphology, linking tubulation to decreased interfacial tension and increased cell hydrophobicity.

天体物理学Astrophysics

A massive helium star with a sufficiently strong magnetic field to form a magnetar

有饶富强磁场组成磁星的大品质氦恒星

▲ 作者 ：TOMER SHENAR, GREGG A. WADE, PABLO MARCHANT et al.

▲ 链接 ：https://www.science.org/doi/full/10.1126/science.ade3293

▲ 摘要：

磁星是高度磁化的中子星，但组成机制尚不清晰。出书光谱以发射线为主的周论富氦恒星，被称为沃尔夫-拉叶星。

咱们用光谱偏振法审核了双星零星HD 45166，并运用档案数据重新合成了它的轨道。咱们发现该星系中有一颗沃尔夫-拉叶星，其品质是太阳的2倍，磁场为43千高斯  。

恒星演化合计表明，这颗星将爆炸成为一颗超新星，而它的磁场强盛到足以让超新星留下磁星遗迹 。咱们提出磁化的沃尔夫-拉叶星是由两颗低品质氦恒星并吞组成的。

▲ Abstract：

Magnetars are highly magnetized neutron stars, the formation mechanism of which is unknown. Hot helium-rich stars with spectra dominated by emission lines are known as Wolf-Rayet stars. We observed the binary system HD 45166 using spectropolarimetry and reanalyzed its orbit using archival data. We found that the system contains a Wolf-Rayet star with a mass of 2 solar masses and a magnetic field of 43 kilogauss. Stellar evolution calculations indicate that this component will explode as a supernova, and that its magnetic field is strong enough for the supernova to leave a magnetar remnant. We propose that the magnetized Wolf-Rayet star formed by the merger of two lower-mass helium stars.

光学Optics

Overcoming losses in superlenses with synthetic waves of complex frequency

用复频率分解波克制超透镜斲丧

▲ 作者：FUXIN GUAN, XIANGDONG GUO, KEBO ZENG et al.

▲ 链接 ：https://www.science.org/doi/full/10.1126/science.adi1267

▲ 摘要：

揭示出光阴衰减行动的复频率光波被提出经由引入伪造增益来对于消超透镜的本征损失，可是由于具备意间衰减的成像丈量难题 ，不断很难在试验中实现。

在这项钻研中，咱们提出了一种基于实际频率丈量的多频措施来构建复频率光波。这种措施应承咱们在试验上实现伪造增益并审核深亚波长图像 。咱们的钻研为克制成像以及传感运用中等离子体零星的固有斲丧提供了一个适用的处置妄想 。

▲ Abstract ：

Optical waves of complex frequency that exhibit a temporally attenuating behavior have been proposed to offset the intrinsic losses in superlenses through the introduction of virtual gain, but experimental realization has been lacking because of the difficulty of imaging measurements with temporal decay. In this work, we present a multifrequency approach to constructing synthetic excitation waves of complex frequency based on measurements at real frequencies. This approach allows us to implement virtual gain experimentally and observe deep-subwavelength images. Our work offers a practical solution to overcome the intrinsic losses of plasmonic systems for imaging and sensing applications.

物理学Physics

Ergodicity breaking in rapidly rotating C60 fullerenes

快捷旋转的C60富勒烯的遍历性破损

▲ 作者 ：LEE R. LIU, DINA ROSENBERG et al.

▲ 链接：https://www.science.org/doi/full/10.1126/science.adi6354

▲ 摘要 ：

在这里，咱们陈说了在一个亘古未有的大份子12C60中审核到的旋转遍历性破损 ，这是从它的二十面体旋转振动精粗妄想陆续定的
。

遍历性断裂爆发在远低于振动遍历性阈值的中间，而且随着角动量的削减，在遍历以及非遍历形态之间展现出一再转变 。

这些特殊的能源学源头于份子的对于称、巨细以及刚性的组合，突出了它与介不雅量子零星中泛起天气的相关性
。

▲ Abstract：

Here, we report the observation of rotational ergodicity breaking in an unprecedentedly large molecule, 12C60, determined from its icosahedral rovibrational fine structure. The ergodicity breaking occurs well below the vibrational ergodicity threshold and exhibits multiple transitions between ergodic and nonergodic regimes with increasing angular momentum. These peculiar dynamics result from the molecule’s distinctive combination of sy妹妹etry, size, and rigidity, highlighting its relevance to emergent phenomena in mesoscopic quantum systems.

生物学Biology

Design of stimulus-responsive two-state hinge proteins

宽慰反映双态铰链卵白的妄想

▲ 作者：FLORIAN PRAETORIUS, PHILIP J. Y. LEUNG et al.

▲ 链接 ：https://www.science.org/doi/full/10.1126/science.adg7731

▲ 摘要：

妄想具备两种差距但妄想残缺的卵白质是卵白质妄想中的一大挑战，由于它需要雕刻具备两个差距最小值的能量景不雅 。

在此
 ，咱们形貌了“铰链”卵白的妄想，它在不配体的情景下可能组成一种妄想形态 ，在配体存在的情景下组成另一种妄想形态 。X射线晶体学 、电子显微镜、双电子-电子共振光谱以及散漫丈量表明，尽管存在清晰的妄想差距，但这两种形态的妄想具备原子水平的精度，而且构象失调以及散漫失调是详尽耦合的
。

▲ Abstract ：

Designing proteins with two distinct but fully structured conformations is a challenge for protein design as it requires sculpting an energy landscape with two distinct minima. Here we describe the design of “hinge” proteins that populate one designed state in the absence of ligand and a second designed state in the presence of ligand. X-ray crystallography, electron microscopy, double electron-electron resonance spectroscopy, and binding measurements demonstrate that despite the significant structural differences the two states are designed with atomic level accuracy and that the conformational and binding equilibria are closely coupled.

古生物学Paleontology

Pre–Younger Dryas megafaunal extirpation at Rancho La Brea linked to fire-driven state shift

新仙女木时期以前，拉布雷亚牧场的巨型植物灭绝与火灾驱动的形态转变无关

▲ 作者：F. ROBIN O’KEEFE, REGAN E. DUNN et al.

▲ 链接
：https://www.science.org/doi/full/10.1126/science.abo3594

▲ 摘要：

更新世巨型植物灭绝的原因很难判断，部份原因是化石记实的较差时空分说率拦阻了物种消逝与考古以及情景数据的对于齐。咱们在加州拉布雷亚牧场的大型植物遗迹中取患上172个新的喷射性碳年月
，光阴距今1.56万年至1万年前。

有7种灭绝的巨型植物消逝于1.29 万年前 ，在新仙女木期开始前 。与高分说率地域数据集的比力表明，这些消逝与暖期（1.469 ~ 1.289万年）干旱化以及植被变更引起的生态形态转变相宜合。

光阴序列模子表明，大规模火灾是物种灭绝的主要原因，而这种形态转变的催化剂可能是人类对于干旱、变紧张越来越简略迸负气灾的生态零星的影响 。

▲ Abstract
：

The cause, or causes, of the Pleistocene megafaunal extinctions have been difficult to establish, in part because poor spatiotemporal resolution in the fossil record hinders alignment of species disappearances with archeological and environmental data. We obtained 172 new radiocarbon dates on megafauna from Rancho La Brea in California spanning 15.6 to 10.0 thousand calendar years before present (ka). Seven species of extinct megafauna disappeared by 12.9 ka, before the onset of the Younger Dryas. Comparison with high-resolution regional datasets revealed that these disappearances coincided with an ecological state shift that followed aridification and vegetation changes during the B?lling-Aller?d (14.69 to 12.89 ka). Time-series modeling implicates large-scale fires as the primary cause of the extirpations, and the catalyst of this state shift may have been mounting human impacts in a drying, warming, and increasingly fire-prone ecosystem.

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