Scan-less 3D microscopy based on spatiotemporal encoding on a single-cavity dual-comb laser.

Dual-comb microscopy enables high-speed and high-precision optical sampling by simultaneously extracting both amplitude and phase information from the interference signals with frequency division multiplexing. In this Letter, we introduce a spatiotemporal encoding approach for dual-comb microscopy that overcomes previous limitations such as mechanical scanning, low sampling efficiency, and system complexity. By employing free-space angular-chirp-enhanced delay (FACED) and a low-noise single-cavity dual-comb laser, we achieve scan-less 3D imaging with nanometer precision and a 3D distance-imaging rate of 330 Hz, restricted only by the repetition rate difference of the dual-comb laser. Specifically, the FACED unit linearly arranges the laser beam into an array. A grating subsequently disperses this array transversely into lines, facilitating ultrafast spectroscopic applications that are 1-2 orders of magnitude quicker than traditional dual-comb methods. This spatiotemporal encoding also eases the stringent conditions on various dual-comb laser parameters, such as repetition rates, coherence, and stability. Through carefully designed experiments, we demonstrate that our scan-less system can measure 3D profiles of microfabricated structures at a rate of 7 million pixels per second. Our method significantly enhances measurement speed while maintaining high precision, using a compact light source. This advancement has the potential for broad applications, including phase imaging, surface topography, distance ranging, and spectroscopy.

DNA-binding activity of STAT3 increased in hypothalamus of DIO mice; the reduction of STAT3 phosphorylation may facilitate leptin signaling.

Leptin-mediated DNA-binding activity of STAT3 in hypothalamus plays crucial roles in the maintenance of energy homeostasis in lean mice; however its effects still remains unclear in case of leptin resistance in mice with diet induced obesity (DIO). In this study significant elevation of both basal and exogenously leptin-treated DNA-binding activity of STAT3 was detected using EMSA in the hypothalamus of male C57BL/6J mice fed high-fat diet for 10 wks, in concomitant with hyperleptinemia, high body weight, high fat mass, and hyperphagia as well as decreased POMC expression. The studies in vitro showed that both DNA binding activity and the proximal SBE of POMC promoter was essential to leptin-mediated POMC expression. However, the diminution of STAT3 phosphorylation, achieved by S3I-201 or a FoxO1 mutant, facilitated leptin-mediated POMC expression. The findings here demonstrated excess STAT3 activity negatively regulated POMC expression in hypothalamus of DIO mice, and suggested the limitation of STAT3 activity may promote leptin signaling.

Ultrafast 3D nanofabrication via digital holography.

There has been a compelling demand of fabricating high-resolution complex three-dimensional (3D) structures in nanotechnology. While two-photon lithography (TPL) largely satisfies the need since its introduction, its low writing speed and high cost make it impractical for many large-scale applications. We report a digital holography-based TPL platform that realizes parallel printing with up to 2000 individually programmable laser foci to fabricate complex 3D structures with 90 nm resolution. This effectively improves the fabrication rate to 2,000,000 voxels/sec. The promising result is enabled by the polymerization kinetics under a low-repetition-rate regenerative laser amplifier, where the smallest features are defined via a single laser pulse at 1 kHz. We have fabricated large-scale metastructures and optical devices of up to centimeter-scale to validate the predicted writing speed, resolution, and cost. The results confirm our method provides an effective solution for scaling up TPL for applications beyond laboratory prototyping.

[Analysis of clinicopathologic features and morphogenesis of carcinoid tumorlets in the lung with bronchiectasis].

OBJECTIVE: To describe the clinicopathologic features and immunophenotypes of carcinoid tumorlets in the lung with bronchiectasis, and to study the morphogenesis of these tiny tumors. METHODS: The histopathologic characteristics of 3 bronchiectasis cases with carcinoid tumorlets, 11 bronchiectasis and 2 normal lungs were studied. Specific markers of the tiny tumors and the number of neuroendocrine cells (NECs) in the airway mucosa were immunohistochemically detected by EnVision method. RESULTS: The tumorlets in the lungs presented as multi-focal nodules and most were displayed only under microscopy. These cells were arranged in clusters and foci of fascicles which were situated in the surrounding bronchial wall and bronchioles adjacent to bronchiectatic lesion, or in the scar tissues. The tiny tumors were consisted of short fusiform cells and small ovoid cells. Their nuclei were circular, oval or long fusiform and the cells were strongly argyrophilic on Grimelius staining. Intensive positive immunostaining for calcitonin, chromogranin A, NSE and gastrin were detected. Weak positive for CK, EMA, S-100 and focal positive for HC, ACTH, 5-HT were also observed. Proliferative NECs in airway mucosa adjacent to the tiny tumors increased significantly in number, compared with those in the airway mucosa of bronchiectasis without tumorlets and normal lungs (P < 0.001, respectively). CONCLUSIONS: The clinicopathologic features and immunophenotypes of carcinoid tumorlets resemble carcinoid tumors. They are the early stage of carcinoid development. Their development may be related to the chronic pulmonary damage resulting in hypoxia and stimulating the proliferation of NECs. These pulmonary carcinoid tumorlets can be used as a model to study the tumorigenesis of carcinoid carcinoma of the lung.

Single-walled carbon nanotubes coated fibers for solid-phase microextraction and gas chromatography-mass spectrometric determination of pesticides in Tea samples.

Using a single-walled carbon nanotubes (SWCNTs) as stationary phase of solid-phase microextraction (SPME) fibers, a simple, low cost and environmentally friendly method for extraction of 13 pesticides in Tea samples has been developed following gas chromatography-mass spectrometric determination. Potential factors affecting the extraction efficiency were investigated and optimized, including extraction and desorption time, extraction temperature, stirring rate, solution pH and ionic strength. Under optimized conditions, the linearity of the developed method was in the range of 0.125-25 ng/mL with correlation coefficients greater than 0.9928 and the limits of detections (LODs) were 0.027-0.23 ng/mL (S/N=3). Meanwhile, the relative standard deviations (RSDs) for five successive measurements with single fiber, fiber-to-fiber, day-to-day were 2.3-13.0, 8.2-14.6 and 4.1-12.5%, respectively, indicating good reproducibility of the proposed method. The fiber had high extraction efficiency for studied pesticides in comparison with commercial poly(dimethylsiloxane) (PDMS) and polyacrylate (PA) fibers and could be used for more than 70 times without decrease of efficiency. The developed method was successfully applied for the analysis of real samples including green Tea, oolong Tea, white Tea, and flower Tea, and the recoveries of the pesticides spiked in these samples ranged from 75.1 to 118.4%. Chlorfenapyr and lambda-cyhalothrin were found in the Tea samples bought randomly from local market. The results demonstrated that the developed SWCNTs-SPME method was a simple, efficient pretreatment and enrichment procedure for pesticides in complex matrices.