다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Researchers demonstrate the ability to multiplex and transfer data between twisted beams of light with different amounts of orbital angular momentum — a development that provides new opportunities for increasing the data capacity of free-space optical communications links.

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Terabit free-space data transmission employing orbital angular momentum multiplexing

Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators in condensed matter, recent advances have shown how to engineer analogous effects also for photons, leading to remarkable phenomena such as the robust unidirectional propagation of light, which hold great promise for applications. Thanks to the flexibility and diversity of photonics systems, this field is also opening up new opportunities to realize exotic topological models and to probe and exploit topological effects in new ways. This article reviews experimental and theoretical developments in topological photonics across a wide range of experimental platforms, including photonic crystals, waveguides, metamaterials, cavities, optomechanics, silicon photonics, and circuit QED. A discussion of how changing the dimensionality and symmetries of photonics systems has allowed for the realization of different topological phases is offered, and progress in understanding the interplay of topology with non-Hermitian effects, such as dissipation, is reviewed. As an exciting perspective, topological photonics can be combined with optical nonlinearities, leading toward new collective phenomena and novel strongly correlated states of light, such as an analog of the fractional quantum Hall effect.

Topological Photonics

/pdf/efficient-separation-of-the-orbital-angular-momentum-1x23f79bbm.pdf

Efficient separation of the orbital angular momentum eigenstates of light

Crustal architecture in Northern Mozambique : resultsfrom a regional bedrock mapping project [abstract]

The mechanism by which light is slowed through ruby has been the subject of great debate. To distinguish between the two main proposed mechanisms, we investigate the problem in the time domain by modulating a laser beam with a chopper to create a clean square wave. By exploring the trailing edge of the pulsed laser beam propagating through ruby, we can determine whether energy is delayed beyond the input pulse. The effects of a time-varying absorber alone cannot delay energy into the trailing edge of the pulse, as a time-varying absorber can only attenuate a coherent pulse. Therefore, our observation of an increase in intensity at the trailing edge of the pulse provides evidence for a complicated model of slow light in ruby that requires more than just pulse reshaping. In addition, investigating the Fourier components of the modulated square wave shows that harmonic components with different frequencies are delayed by different amounts, regardless of the intensity of the component itself. Understanding the difference in delays of the individual Fourier components of the modulated beam reveals the cause of the distortion the pulse undergoes as it propagates through the ruby.

Slow light in ruby: delaying energy beyond the input pulse

Instabilities of counterpropagating vector waves in a nonlinear Kerr medium (A)

We report the observation of intrinsic instabilities in the reflectivity of a barium titanate, self-pumped phase conjugate mirror (SPPCM). In such a device, a laser beam is focused into a crystal of barium titanate, and a beam is generated within the crystal that has been shown by FEINBERG [1] to be the phase conjugate of the incident laser beam. A model has been proposed [2] to explain this effect in terms of self beam fanning: the incident laser beam breaks up into new spatial components by self focusing. These components undergo total internal reflection at the corners of the crystal and are redirected in such a way that they intercept the incident laser beam, thereby forming the counterpropagating pump waves needed to create the phase conjugate beam by the usual four-wave mixing process. Since the pump waves grow from noise by a highly nonlinear process, and interact strongly with the incident and conjugate beams, it might be expected that the output beam would show unstable or even chaotic behavior. An alternative model for self-pumped phase conjugation has been presented by LAM [3]. According to this model, the phase conjugate return is formed by a two-beam stimulated scattering process. This process would not be expected to produce a chaotic output.

Robert W. Boyd

Papers

Efficient separation of the orbital angular momentum eigenstates of light

Crustal architecture in Northern Mozambique : resultsfrom a regional bedrock mapping project [abstract]

Slow light in ruby: delaying energy beyond the input pulse

Instabilities of counterpropagating vector waves in a nonlinear Kerr medium (A)

Instabilities in a Self-Pumped Barium Titanate Phase Conjugate Mirror