Fabrication of 2D silicon nano-mold by side etch lift-off method.

Nano-imprint technology is a method of nano-pattern reproduction, has the characteristics of high resolution, high throughput, and low-cost. It can reduce the complexity and cost of the equipment while improving the resolution, which considered a promising industrial production technology. The key to nanoimprinting lies in the mold, and the quality of the mold directly determines the quality of the imprinted graphics. Here, a method for fabricating sub-100 nm concave 2D silicon nano-mold by side etch lift-off is proposed. The effects of different wet etching time and the metal deposition angle on the width of nanochannels were studied. The measurement result of dry etching shows that on the entire 4 inch silicon wafer, the width of the nanochannel varies by 4% and the depth by 2%. The width of the nanochannel between chips varies by 0.7%, and the depth variation is 1%. With this new method, high-precision and large-scale silicon nano-mold can be produced, which has great potential for realizing high-precision and low-cost manufacturing of nano devices.

Beam alignment based on two-dimensional power spectral density of a near-field image.

Beam alignment is crucial to high-power laser facilities and is used to adjust the laser beams quickly and accurately to meet stringent requirements of pointing and centering. In this paper, a novel alignment method is presented, which employs data processing of the two-dimensional power spectral density (2D-PSD) for a near-field image and resolves the beam pointing error relative to the spatial filter pinhole directly. Combining this with a near-field fiducial mark, the operation of beam alignment is achieved. It is experimentally demonstrated that this scheme realizes a far-field alignment precision of approximately 3% of the pinhole size. This scheme adopts only one near-field camera to construct the alignment system, which provides a simple, efficient, and low-cost way to align lasers.

Early Detection of Gastric Intramucosal Adenocarcinoma on 68 Ga-FAPI PET/CT.

ABSTRACT: 18 F-FDG PET/CT may sometimes not be an ideal imaging method for gastric adenocarcinoma. Because of the unstable physiological uptake of 18 F-FDG in the gastrointestinal tract and muscles, it may interfere with the detection of lesions. We present a case of gastric intramucosal adenocarcinoma detected by 68 Ga-FAPI PET/CT in a patient with nasopharyngeal carcinoma.

Investigation of Voids Characteristics in an Asphalt Mixture Exposed to Salt Erosion Based on CT Images.

The performance of an asphalt mixture will deteriorate under the condition of salt erosion, but there are different opinions on the mechanism of deterioration. Few studies have focused on the relation between the change of void characteristics and performance deterioration of an asphalt mixture exposed to salt erosion. To explore the relation between the air voids characteristics of an asphalt mixture and mechanical damage under salt erosion, the mechanical damage in an asphalt mixture was measured by splitting strength. The asphalt mixture specimens, immersion solutions, asphalt mortar, and aggregate were scanned with CT technology. To segment the voids, the Otsu method was used over asphalt mortar and solution range of CT values. A three-dimensional reconstruction of the CT image was performed with Mimics 20 software to calculate the asphalt mixture's void characteristics. On this basis, the relationships between the change in void characteristics and splitting strength were analyzed. The results showed that the ideal calculated void fraction can be obtained by threshold segmentation of the image void/asphalt mortar interface with the local CT value Otsu method. Under the salt corrosion environment, the increase of open voids of an asphalt mixture is linearly correlated with the decrease of splitting strength, while salts' crystallization in the open voids produces crystallization pressure, accelerating the volume growth of open voids. The early damage of an asphalt mixture suffered from the salt may be mainly physical damage. These results can provide a useful reference for the performance of damage research on asphalt mixtures in salt enrichment areas.

[Effect of antisense survivin RNA transfection on the growth of ovarian carcinoma SKOV3 cells in vitro and in vivo].

OBJECTIVE: To study the inhibition effect of survivin antisense RNA on the growth of ovarian carcinoma SKOV3 cells, and the tumorigenic ability of the transfected SKOV3 cells implanted subcutaneously in nude mice. METHODS: The recombinant vector pcDNA3-SVVas was constructed by directed cloning of fragments of survivin cDNA into the vector. The ovarian carcinoma SKOV3 cells were transfected with pcDNA3-SVVas by lipofectamine 2000 (SKOV3/SVVas cells), and blank vector pcDNA3 as control (SKOV3/neo cells). The effect of survivin antisense RNA on cell growth was assessed by growth curve. The inhibition of expression of endogenous survivin protein and mRNA was evaluated by immunohistochemical stain and RT-PCR. The apoptosis of cells was assessed by flow cytometry. Twenty-four nude mice were divided into three groups, then SKOV3/SVVas, SKOV3/neo and SKOV3 cells were implanted subcutaneously. The growth of tumor was observed and the tumor volume calculated. RESULTS: The expression of survivin significantly decreased in SKOV3/SVVas cells in comparison to that in SKOV3 and SKOV3/neo cells. The growth of the SKOV3/SVVas cells became significantly slower than those of SKOV3 cells and SKOV3/neo cells (P < 0.01). The expression of survivin protein and mRNA in the SKOV3/SVVas cells were (37.5 +/- 1.0)% and 0.407 +/- 0.022 respectively, compared with SKOV3 [(81.2 +/- 0.4)%, 0.793 +/- 0.042] and SKOV3/neo [(80.4 +/- 0.8)%, 0.734 +/- 0.039]. The difference was significant (P < 0.01). After transfected with pcDNA3-SVVas, cells were found apoptosis in early stage by flow cytometry. The apoptosis rate was (27.4 +/- 9.6)%. There was significant difference between SKOV3/SVVas cells and SKOV3 cells, as well as between SKOV3/SVVas and SKOV3/neo cells (P < 0.05). The tumorigenic ability of SKOV3/SVVas cells was reduced. The first time that tumor could be detected in SKOV3/SVVas group, (14.0 +/- 1.0) days was significantly prolonged compared to SKOV3/neo, (6.1 +/- 0.8) days and SKOV3, (5.8 +/- 0.9) days (P < 0.01). In SKOV3/SVVas group, 5 of 8 nude mice were found tumor, the growth rate of tumor was slower compared with the other two groups. When compared in volume, the difference was significant (P < 0.01). CONCLUSIONS: Stable expression of survivin antisense RNA can effectively inhibit the growth of SKOV3 cells and reduce the expression of endogenous survivin proteins and mRNA, induce the apoptosis of cells. Survivin antisense RNA can inhibit the tumorigenesis of SKOV3 cells in nude mice.