MicroRNAs (miRNAs) are endogenous and noncoding single-stranded RNA molecules with a length of approximately 18–25 nucleotides, which play an undeniable role in early cancer screening. Therefore, it is very important to develop an ultrasensitive and highly specific method for detecting miRNAs. Here, we present a bottom-up assembly approach for modifying glass microtubes with silica nanowires (SiNWs) and develop a label-free sensing platform for miRNA-21 detection. The three-dimensional (3D) networks formed by SiNWs make them abundant and highly accessible sites for binding with peptide nucleic acid (PNA). As a receptor, PNA has no phosphate groups and exhibits an overall electrically neutral state, resulting in a relatively small repulsion between PNA and RNA, which can improve the hybridization efficiency. The SiNWs-filled glass microtube (SiNWs@GMT) sensor enables ultrasensitive, label-free detection of miRNA-21 with a detection limit as low as 1 aM at a detection range of 1 aM–100 nM. Noteworthy, the sensor can still detect miRNA-21 in the range of 102–108 fM in complex solutions containing 1000-fold homologous interference of miRNAs. The high anti-interference performance of the sensor enables it to specifically recognize target miRNA-21 in the presence of other miRNAs and distinguish 1-, 3-mismatch nucleotide sequences. Significantly, the sensor platform is able to detect miRNA-21 in the lysate of breast cancer cell lines (e.g., MCF-7 cells and MDA-MB-231 cells), indicating that it has good potential in the screening of early breast cancers.
The coherent group is realized as the important way of the high-power optical fiber laser.The twin-core photonic crystal fiber coherent output was obtained,the core diameter is 2.05μm,a hole-to-hole spacing is 2.07μm,the airhole diameter is 1.44 μm,output power up to 30μW.This achievement will be to a new direction for the fiber lasers.
In this paper a new phase contrast method with fringe contrast adjustable is proposed. In the Fourier plane of the object wave, two Ronchi gratings i.e., a central grating and a surrounding grating, are used to modulate the phases of the undiffracted and diffracted components, respectively. By loading the two gratings separately on spatial light modulator, the undiffracted and diffracted components can be measured independently, which simplify greatly the reconstruction process. Besides, the fringe contrast of the phase contrast interferogram can be adjusted by changing the modulation depth of the two gratings. The feasibility of the proposed method is verified by theoretical analysis and experiment.
When structured illumination is used in digital holographic microscopy (DHM), each direction of the illumination fringe is required to be shifted at least three times to perform the phase-shifting reconstruction. In this paper, we propose a scheme for spatial resolution enhancement of DHM by using the structured illumination but without phase shifting. The structured illuminations of different directions, which are generated by a spatial light modulator, illuminate the sample sequentially in the object plane. The formed object waves interfere with a reference wave in an off-axis configuration, and a CCD camera records the generated hologram. After the object waves are reconstructed numerically, a synthetic aperture is performed by an iterative algorithm to enhance the spatial resolution. The resolution improvement of the proposed method is proved and demonstrated by both simulation and experiment.
Abstract An efficient and selective Pd‐catalyzed 1,4‐dihydrosilylation of alkynones has been firstly described to provide a convenient access to β‐aryl carbonyl compounds under mild conditions. Various β‐aryl carbonyl compounds have been synthesized with good yields and functional group tolerance. β‐aryl carbonyl products have been shown to be further application in the synthesis of secondary alcohol, silyl‐ether, trifluoromethylsilyl‐ether and vinyl acetate derivative.
To observe the temperature change of traditional silver needle in the human body during the burning of moxa ball.Thirty-six healthy volunteers were randomly divided into a single-needle group and a multi-needle group, 18 cases in each group. For both groups, one silver needle (18 cm in length, 1.1 mm in diameter), which was adopted in this research to measure the temperature change, was punctured in the insertion point of the volunteer (inside the top of the left buttock, 7 cm under the edge of the highest point of the iliac crest, 7 cm lateral to the dorsomedian line), then another four silver needles were punctured 2 cm respectively anterior, posterior and lateral to the insertion point in the multi-needle group, and all the silver needles were inserted with 6 cm depth. Afterigniting the 1.3 g moxa ball on the needle tail, the temperature of the measuring points that were 3 mm, 33 mm, and 63 mm above the silver needle tip were recorded separately by digital temperature measuring instrument.The peak temperature of the three measuring points in the single-needle group was all around 41 degrees C, while those in the multi-needle group were around 43 degrees C, which had significant differences (all P < 0.05), but no significant differences among the highest temperature of the measuring points in the same group could be found (all P > 0.05). The highest temperature of moxa ball in the single needle group was (611.16 +/- 6.91) degrees C, while that of the central moxa ball in the multi-needle group was (628.94 +/- 8.99) degrees C, the difference of which was significant difference (P < 0.01).The temperature conductivity of the silver needle is very well, so the heat of the moxa ball could pass from the tail of needle to the tip during the warming treatment. The peak temperature on the body, tip of the silver needle in the multi-needle group is higher than those in the single needle group. Also, the peak temperature of multi-moxa ball is higher than that of single moxa ball.
Abstract Optical sectioning structured illumination microscopy (OS‐SIM) is a fast, minimally invasive 3D imaging technique that has found widespread application in the biosciences. It is based on sample illumination with several illumination fringe patterns featuring distinct mutual phase shifts, from which an axially sectioned image is reconstructed. Its optical sectioning capability is commonly attributed to the attenuation of the fringe modulation of light collected from planes displaced from the focal plane. However, in addition to this effect, which is governed solely by the detection optics, optical sectioning can be further enhanced by confining the fringe modulation axially via partially coherent illumination (PCI). To establish guidelines for optimal illumination field shaping, both theoretically and experimentally are investigated, the optical sectioning strength of OS‐SIM upon variation of the two key parameters, modulation period and angular spectrum of the incident illumination. By using PCI with OS‐SIM, nearly fivefold and 1.4‐fold enhanced axial resolution have achieved for scattering (non‐fluorescent) and fluorescent samples, respectively. This work elucidates the optical sectioning mechanism of OS‐SIM and provides a perspective for further optimization.
In a two-photon excitation fluorescence volume imaging (TPFVI) system, an axicon is used to generate a Bessel beam and at the same time to collect the generated fluorescence to achieve large depth of field. A slice-by-slice diffraction propagation model in the frame of the angular spectrum method is proposed to simulate the whole imaging process of TPFVI. The simulation reveals that the Bessel beam can penetrate deep in scattering media due to its self-reconstruction ability. The simulation also demonstrates that TPFVI can image a volume of interest in a single raster scan. Two-photon excitation is crucial to eliminate the signals that are generated by the side lobes of Bessel beams; the unwanted signals may be further suppressed by placing a spatial filter in the front of the detector. The simulation method will guide the system design in improving the performance of a TPFVI system.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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