There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

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A roadmap for graphene

A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation in photonic crystal fiber

We present a weakly-supervised deep learning framework for human breast cancer-related optical biomarker discovery based on label-free autofluorescence multiharmonic (SLAM) microscopy. This framework consists of three stages: self-supervised consistency training for image representation learning at multiple scales; cancer region identification by weakly-supervised Multiple Instance Learning (MIL); optical biomarker discovery based on channel-wise attribution maps. Currently, the model has achieved an average AUC of 0.86 on the breast cancer global detection task. The attribution maps on different scales highlight distinct structures in SLAM which facilitate new insights into tumor micro-environment and field cancerization. 

Explainable weakly-supervised learning for optical biomarker discovery in multiphoton virtual histology

Contrast in optical coherence tomography (OCT) images is often limited, particularly when pathological tissue is morphologically or optically similar to normal tissue. We present novel contrast enhancing methods designed to selectively identify tissues of interest.

Contrast enhancement methods for optical coherence tomography

An intraoperative probe and a system for optically imaging a surgically significant volume of tissue or other scattering medium. An illumination source generates an illuminating beam that is conveyed to the vicinity of the tissue and a beam splitter, that may be no more than an optical phase reference, splits the illuminating beam into a sample beam along a sample beam path and a reference beam along a reference beam path. A scanning mechanism scans a portion of the sample beam across a section of the scattering medium, while a detector detects return beams from both the reference beam path and the sample beam path and generates an interference signal. A processor computationally moves an effective focus of the sample beam without physical variation of focus of the sample beam. The probe may have a sterilizable fairing that may be detachable.

Handheld optical probe in combination with a fixed-focus fairing

Nonlinear label-free microscopy techniques have shown great promise for analyzing biological tissues with an unmatched level of information. These techniques are capable of identifying intrinsic optical signals generated in response to ultrafast laser pulses. A roadblock in fast label-free imaging is the limited signal-to-noise ratio (SNR), due to the low number of photons close to the noise level. We implemented heterodyne detection of the third-order signals to overcome this limit and surpass the 1/f noise. Our method increases the SNR by a factor of 2.3, leading to a factor of 5 reduction in imaging time. 

High signal-to-noise ratio rapid third-order label-free and harmonic generation microscopy of neural dynamics through electronic heterodyne amplification (Conference Presentation)

Stephen A. Boppart

Papers

Explainable weakly-supervised learning for optical biomarker discovery in multiphoton virtual histology

Contrast enhancement methods for optical coherence tomography

Handheld optical probe in combination with a fixed-focus fairing

High signal-to-noise ratio rapid third-order label-free and harmonic generation microscopy of neural dynamics through electronic heterodyne amplification (Conference Presentation)