《自然》（20190328出版）一周论文导读

翻译 | 宗华

Nature, 28 March 2019, Volume 567 Issue 7749

《自然》2019年3月28日，第7749期567卷

健康Health

 

Neoantigen-directed immune escape in lung cancer evolution

肺癌进化中的新抗原免疫逃逸

▲ 作者：Rachel Rosenthal, Elizabeth Larose Cadieux, et al

▲ 链接：

https://www.nature.com/articles/s41586-019-1032-7

▲ 摘要：

进化中的癌症和动态免疫微环境之间的相互作用仍不清楚。

这里，我们利用RNA测序和组织病理学评估的肿瘤浸润淋巴细胞估计，分析了88例早期未治疗非小细胞肺癌的258个区域。

肿瘤之间和肿瘤内部的免疫浸润不同，而且不同的免疫微环境中出现新抗原表达功能障碍的机制也不同。

稀疏浸润的肿瘤在肿瘤进化过程中表现出新抗原编辑功能的减弱，这表明以前的克隆新抗原存在历史性免疫编辑或复制数的丢失。

免疫浸润肿瘤区域表现出持续的免疫编辑，并出现人类白细胞抗原杂合性丢失或表达的新抗原缺失。

我们发现，含有新抗原突变的启动子高甲基化是免疫编辑的表观遗传机制。

▲ Abstract

The interplay between an evolving cancer and a dynamic immune microenvironment remains unclear. Here we analyse 258 regions from 88 early-stage, untreated non-small-cell lung cancers using RNA sequencing and histopathology-assessed tumour-infiltrating lymphocyte estimates. Immune infiltration varied both between and within tumours, with different mechanisms of neoantigen presentation dysfunction enriched in distinct immune microenvironments. Sparsely infiltrated tumours exhibited a waning of neoantigen editing during tumour evolution, indicative of historical immune editing, or copy-number loss of previously clonal neoantigens. Immune-infiltrated tumour regions exhibited ongoing immunoediting, with either loss of heterozygosity in human leukocyte antigens or depletion of expressed neoantigens. We identified promoter hypermethylation of genes that contain neoantigenic mutations as an epigenetic mechanism of immunoediting.

Glucocorticoids promote breast cancer metastasis

糖皮质激素促进乳腺癌转移

▲ 作者：Milan M. S. Obradović, Baptiste Hamelin, Nenad Manevski, et al

▲ 链接：

https://www.nature.com/articles/s41586-019-1019-4

▲ 摘要：

疾病恶化过程中形成的肿瘤内部或肿瘤与转移瘤之间的多样性，是治疗的一个严重障碍。

这里，通过对源自人类患者的小鼠异种移植模型的肿瘤和匹配转移瘤进行转录谱分析，我们证实了癌症位点特异性表型和远处转移瘤中糖皮质激素受体活性的增加。

糖皮质激素受体介导应激激素及其合成衍生物的作用。

这些激素在临床上广泛用作抗炎和免疫抑制剂。

我们发现，乳腺癌恶化过程中应激激素的增加导致糖皮质激素受体在远处转移部位的激活、定植增加和存活率降低。

▲ Abstract

Diversity within or between tumours and metastases (known as intra-patient tumour heterogeneity) that develops during disease progression is a serious hurdle for therapy. Here, using transcriptional profiling of tumours and matched metastases in patient-derived xenograft models in mice, we show cancer-site-specific phenotypes and increased glucocorticoid receptor activity in distant metastases. The glucocorticoid receptor mediates the effects of stress hormones, and of synthetic derivatives of these hormones that are used widely in the clinic as anti-inflammatory and immunosuppressive agents. We show that the increase in stress hormones during breast cancer progression results in the activation of the glucocorticoid receptor at distant metastatic sites, increased colonization and reduced survival.

 

物理学Physics

Error mitigation extends the computational reach of a noisy quantum processor

误差缓解扩展了有噪声量子处理器的计算范围

▲ 作者：Abhinav Kandala, Kristan Temme, Antonio D. Córcoles, et al

▲ 链接：

https://www.nature.com/articles/s41586-019-1040-7

▲ 摘要：

量子计算是一种与经典计算方法完全不同的计算范式。

它受益于经过理论证明的针对某些问题的加速方法，可用来研究量子系统性质。

然而，由于物理计算元素（量子位）固有的脆弱性，要获得量子计算相对于传统计算的优势，不仅需要极低的量子位运算错误率，还需要大量的物理量子位，从而通过量子误差校正实现容错。

这里，我们在超导量子处理器上演示了一种错误缓解协议，并且在不需要额外硬件修改的情况下增强了其计算能力。

我们将该协议应用于规范的单量子位和双量子位实验，并将其扩展到量子化学和磁学中哈密顿函数的变分优化。

▲ Abstract

Quantum computation, a paradigm of computing that is completely different from classical methods, benefits from theoretically proved speed-ups for certain problems and can be used to study the properties of quantum systems. Yet, because of the inherently fragile nature of the physical computing elements (qubits), achieving quantum advantages over classical computation requires extremely low error rates for qubit operations, as well as substantial physical qubits, to realize fault tolerance via quantum error correction. Here we demonstrate this error mitigation protocol on a superconducting quantum processor, enhancing its computational capability, with no additional hardware modifications. We apply the protocol to mitigate errors in canonical single- and two-qubit experiments and then extend its application to the variational optimization of Hamiltonians for quantum chemistry and magnetism.

Observation of unconventional chiral fermions with long Fermi arcs in CoSi

对硅化钴中具有长费米弧的非常规手性费米子的研究

▲ 作者：Zhicheng Rao, Hang Li, Tiantian Zhang, Shangjie Tian, et al

▲ 链接：

https://www.nature.com/articles/s41586-019-1031-8

▲ 摘要：

手性——与其镜像不一致的物体几何特性——存在于自然界中，比如分子、晶体、星系和生命形式中。

这里，利用角分辨光发射光谱，我们揭示了在硅化钴中费米能级附近的带交叉点上存在的两种非常规手性费米子——自旋-1和电荷-2费米子。

这些手性费米子在(001)表面上的映射由横跨整个布里渊区表面的巨大费米弧连接起来。

这些手性费米子在布里渊区的中心或者角落通过晶体对称性实现，使硅化钴成为只有一对手性节点的系统。

该手性节点拥有动量空间的大分离和超长表面费米弧。这和外尔半金属形成鲜明对比，后者拥有多对外尔节点的小分离。

▲ Abstract

Chirality—the geometric property of objects that do not coincide with their mirror image—is found in nature, for example, in molecules, crystals, galaxies and life forms. Here, by using angle-resolved photoemission spectroscopy, we reveal two types of unconventional chiral fermion—spin-1 and charge-2 fermions—at the band-crossing points near the Fermi level in CoSi. The projections of these chiral fermions on the (001) surface are connected by giant Fermi arcs traversing the entire surface Brillouin zone. These chiral fermions are enforced at the centre or corner of the bulk Brillouin zone by the crystal symmetries, making CoSi a system with only one pair of chiral nodes with large separation in momentum space and extremely long surface Fermi arcs, in sharp contrast to Weyl semimetals, which have multiple pairs of Weyl nodes with small separation.

材料Material

 

Colossal barocaloric effects in plastic crystals

塑料晶体中巨大的压热效应

▲ 作者：Bing Li, Yukinobu Kawakita, Seiko Ohira-Kawamura, et al

▲ 链接：

https://www.nature.com/articles/s41586-019-1042-5

▲ 摘要：

目前的制冷技术主要涉及传统蒸汽压缩循环，但由于其巨大的全球变暖潜力，该技术中使用的材料日益引发人们对环境问题的担忧。

作为一种颇有前途的替代技术，基于固态热效应的制冷技术近几十年来受到关注。

这里，我们报告了一种被称为塑料晶体的无序固体的巨大压热效应（CBCEs）。CBCEs是压力引起的相变的冷却效应。

在典型的塑料晶体——新戊二醇中，获得的熵变在近室温下约为389焦耳每千克每开尔文。

依赖于压力的中子散射测量结果表明，塑料晶体中的CBCEs是由这些材料广泛的分子定向排列紊乱、巨大的可压缩性和高度非谐晶格动力学共同作用的结果。

▲ Abstract

Current refrigeration technology mostly involves the conventional vapour compression cycle, but the materials used in this technology are of growing environmental concern because of their large global warming potential. As a promising alternative, refrigeration technologies based on solid-state caloric effects have been attracting attention in recent decades. Here we report colossal barocaloric effects (CBCEs) (barocaloric effects are cooling effects of pressure-induced phase transitions) in a class of disordered solids called plastic crystals. The obtained entropy changes in a representative plastic crystal, neopentylglycol, are about 389 joules per kilogram per kelvin near room temperature. Pressure-dependent neutron scattering measurements reveal that CBCEs in plastic crystals can be attributed to the combination of extensive molecular orientational disorder, giant compressibility and highly anharmonic lattice dynamics of these materials.

Topological chiral crystals with helicoid-arc quantum states

拥有螺旋—弧状量子态的拓扑手性晶体

▲ 作者：Daniel S. Sanchez, Ilya Belopolski, Tyler A. Cochran, et al

▲ 链接：

https://www.nature.com/articles/s41586-019-1037-2

▲ 摘要：

材料中电子的量子行为是现代电子学和信息技术的基础，同时具有拓扑电子和光特性的量子材料对于实现可用于下一代技术的量化电子响应是必不可少的。

这里，我们首次报告了对铑硅家族中手性晶体拓扑量子性质的观察结果。

我们发现，这类材料含有一种物质的量子相。

这种物质由于晶体的结构手性而表现出近乎理想的拓扑表面特性。

这些晶体表面的电子显示出一种非常不寻常的螺旋状费米子结构。

该结构围绕两个高对称动量旋转，展示出电子拓扑手性。

▲ Abstract

The quantum behaviour of electrons in materials is the foundation of modern electronics and information technology, and quantum materials with topological electronic and optical properties are essential for realizing quantized electronic responses that can be used for next generation technology. Here we report the first observation of topological quantum properties of chiral crystals in the RhSi family. We find that this material class hosts a quantum phase of matter that exhibits nearly ideal topological surface properties originating from the crystals’ structural chirality. Electrons on the surface of these crystals show a highly unusual helicoid fermionic structure that spirals around two high-symmetry momenta, indicating electronic topological chirality.

 

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