eMedicine创建于1996年，由近万名临床医师作为作者或编辑参与此临床医学知识库的建设，其中编辑均是来自美国哈佛、耶鲁、斯坦福、芝加哥、德克萨斯、加州大学等各分校医学院的教授或副教授。

eMedicine

A silicon-on-insulator device combining two four-wave-mixing photon-pair sources in an interferometer with a reconfigurable phase shifter is used to create and manipulate non-degenerate or degenerate, path-entangled or path-unentangled photon pairs. A quantum interference visibility of nearly 100% is observed on-chip. This device is a first step towards fully integrated quantum technologies.

On-chip quantum interference between silicon photon-pair sources

Author(s): Dorfman, KE; Schlawin, F; Mukamel, S | Abstract: Conventional nonlinear spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the quantum state of light as novel control knobs and through the variation of photon statistics by coupling to matter. An intuitive diagrammatic approach is presented for calculating ultrafast spectroscopy signals induced by quantum light, focusing on applications involving entangled photons with nonclassical bandwidth properties - known as "time-energy entanglement." Nonlinear optical signals induced by quantized light fields are expressed using time-ordered multipoint correlation functions of superoperators in the joint field plus matter phase space. These are distinct from Glauber's photon counting formalism which uses normally ordered products of ordinary operators in the field space. One notable advantage for spectroscopy applications is that entangled-photon pairs are not subjected to the classical Fourier limitations on the joint temporal and spectral resolution. After a brief survey of properties of entangled-photon pairs relevant to their spectroscopic applications, different optical signals, and photon counting setups are discussed and illustrated for simple multilevel model systems.

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Nonlinear optical signals and spectroscopy with quantum light

Despite progress in detecting circulating tumor cells (CTCs), existing assays still have low sensitivity (1–10 CTC/mL) due to the small volume of blood samples (5–10 mL). Consequently, they can miss up to 103–104 CTCs, resulting in the development of barely treatable metastasis. Here we analyze a new concept of in vivo CTC detection with enhanced sensitivity (up to 102–103 times) by the examination of the entire blood volume in vivo (5 L in adults). We focus on in vivo photoacoustic (PA) flow cytometry (PAFC) of CTCs using label-free or targeted detection, photoswitchable nanoparticles with ultrasharp PA resonances, magnetic trapping with fiber-magnetic-PA probes, optical clearance, real-time spectral identification, nonlinear signal amplification, and the integration with PAFC in vitro. We demonstrate PAFC’s capability to detect rare leukemia, squamous carcinoma, melanoma, and bulk and stem breast CTCs and its clusters in preclinical animal models in blood, lymph, bone, and cerebrospinal fluid, as well as the release of CTCs from primary tumors triggered by palpation, biopsy or surgery, increasing the risk of metastasis. CTC lifetime as a balance between intravasation and extravasation rates was in the range of 0.5–4 h depending on a CTC metastatic potential. We introduced theranostics of CTCs as an integration of nanobubble-enhanced PA diagnosis, photothermal therapy, and feedback through CTC counting. In vivo data were verified with in vitro PAFC demonstrating a higher sensitivity (1 CTC/40 mL) and throughput (up to 10 mL/min) than conventional assays. Further developments include detection of circulating cancer-associated microparticles, and super-resolution PAFC beyond the diffraction and spectral limits.

https://www.mdpi.com/2072-6694/5/4/1691/pdf

Circulating Tumor Cell Detection and Capture by Photoacoustic Flow Cytometry in Vivo and ex Vivo

The relationship between polyploidy and breeding system is of critical importance for understanding evolution and improving the taxonomy of large Rosaceous genera. Reviewing the data available for the family and for tribe Pyreae (formerly subfamily Maloideae) in particular, it appears that hybridization, pseudogamous gametophytic apomixis, polyploidy, and self-compatibility are closely linked. Studies of the evolutionary significance of any one or two of these factors need to consider the others as well. Taxonomic decisions likewise need to be informed by knowledge of how these factors affect patterns of phenetic and genetic variation.

Polyploidy, reproductive biology, and Rosaceae: understanding evolution and making classifications

Polarization-dependent single-beam laser-induced grating-like effects on titanium films

North American black‐fruited hawthorns. II. Floral development of 10‐ and 20‐stamen morphotypes in Crataegus section Douglasii (Rosaceae: Maloideae)

We present a study of the spectral properties of photon pairs generated through the process of spontaneous four-wave mixing (SFWM) in single mode fiber. Our analysis assumes narrowband pumps, which are allowed to be frequency degenerate or nondegenerate. Based on this analysis, we derive conditions on the pump frequencies and on the fiber dispersion parameters which guarantee the generation of ultrabroadband photon pairs. Such photon pairs are characterized by (i) a very large degree of entanglement, and (ii) a very high degree of temporal synchronization between the signal and idler photons. Through a numerical exercise, we find that the use of photonic crystal fiber (PCF) facilitates the fulfilment of the conditions for ultrabroadband photon pair generation; in particular, the spectral region in which emission occurs can be adjusted to particular needs through an appropriate choice of the PCF parameters. In addition, we present a quantum interference effect, resulting from indistinguishable pathways to the same outcome, which can occur when pumping a SFWM source with multiple spectral lines.

Ultrabroadband photon pair preparation by spontaneous four-wave mixing in a dispersion-engineered optical fiber

Abstract This report presents a study of shock wave and cavitation bubble dynamics induced by nanosecond laser pulses in pressurized water. Three methods were used to obtain data from the irradiated sample: (1) pump-probe laser flash shadowgraphy, (2) pressure wave sensing by means of a fiber optic interferometer hydrophone, and (3) a novel technique based on the modulation of spatial transmittance by the cavitation bubble. The medium used in these experiments was distilled water in a chamber under different pressure conditions which included values found in human intraocular liquid. It could be shown that while external pressure does not affect either the shock wave propagation or the initial bubble growth rate, it does affect the first collapse time of the bubble and its maximum diameter. Zusammenfassung Die vorliegende Arbeit untersucht die Dynamik von Schockwellen und Kavitationsblasen, die mittels Nanosekunden-Laserpulsen in unter Druck gesetztem Wasser erzeugt wurden. Dabei wurden drei unterschiedliche Methoden verwendet: (1) Laserflash-Verfahren, (2) Druckwellenmessung mittels faseroptischem Interferometer und (3) eine neuartige Technik basierend auf der Modulation der räumlichen Transmission durch die Kavitationsblase. Die Untersuchungen wurden an destilliertem Wasser unter unterschiedlichen Drücken – u.a. auch physiologische Werte, wie sie intraokular vorkommen – vorgenommen, die mittels einer speziellen Druckkammer erzeugt wurden. Es konnte gezeigt werden, dass weder die Ausbreitung der Schockwelle noch das anfängliche Blasenwachstum durch den äußeren Druck beeinflusst wird, die Kollapszeit der Blase und ihr maximaler Durchmesser jedoch sehr wohl.

Laser-induced cavitation phenomenon studied using three different optically-based approaches – An initial overview of results

Bubble formation is a well identified phenomenon within short (ns) and ultrashort (fs) laser pulses-aqueous media interactions Bubble formation might be produced by three different mechanisms: (1) optical breakdown, (2) rarefraction wave and (3) overheating of the material Experiments where transparent and scattering tissue models that mimic biological tissue were irradiated with a Q-switched, 532 nm, 5 nanosecond, Nd:YAG and Ti:sapphire femtosecond laser systems The type of bubble (transient or permanent) and initial bubble diameter were characterized as a function of time as well as the number of pulses and repetition rate at which they were delivered Threshold fluence for bubble formation in scattering tissue model was also studied Two types of bubbles were identified depending on the number of pulses and the repetition rate at which they were delivered: transient (type 1) and permanent (type 2) bubbles There is an insignificant difference in the fluence required to form a bubble in transparent tissue models regardless of the depth at which the beam was focused; in contrast, for scattering tissue models, the fluence required to form a bubble in deep positions is significantly higher than that of more superficial beam focus positions

Rodger Evans

Papers

Polarization-dependent single-beam laser-induced grating-like effects on titanium films

North American black‐fruited hawthorns. II. Floral development of 10‐ and 20‐stamen morphotypes in Crataegus section Douglasii (Rosaceae: Maloideae)

Ultrabroadband photon pair preparation by spontaneous four-wave mixing in a dispersion-engineered optical fiber

Laser-induced cavitation phenomenon studied using three different optically-based approaches – An initial overview of results

Short and ultrashort laser pulse induced bubbles on transparent and scattering tissue models