Diagnostic Value of Dual-Energy CT in Differentiating Malignant and Benign Thyroid Nodules: A Systematic Review and Meta-Analysis

Objectives: To evaluate the diagnostic performance of the quantitative iodine parameters, including Iodine Concentration (IC), Normalized Iodine Concentration (NIC), and λHU, in distinguishing malignant and benign thyroid nodules. Methods: Relevant studies were searched from Web of Science, PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure database and other complementary sources from inception to May 20, 2020. Study selection, data extraction, quality assessment, and data analyses were performed following the Cochrane standards and the PRISMA-DTA guideline. Results: Eight studies were included (595 patients with 737 thyroid nodules). The pooled sensitivity, specificity and summary diagnostic odds ratio of IC were 79% (95% CI: 69% - 86%), 76% (95% CI: 65% - 84%) and 11 (95% CI: 5 - 27) respectively;those of NIC were 78% (95% CI: 70% - 85%), 80% (95% CI: 74% - 85%) and 15 (95% CI: 9 - 24) respectively;those of λHU were 80% (95% CI: 71% - 87%), 77% (95% CI: 70% - 83%) and 14 (95% CI: 8 - 24) respectively. Conclusion: DECT can be a potential evaluation tool for thyroid nodules. The NIC may be the most sensitive iodine parameter and could be comparable between different DECT machines in thyroid nodule assessment.

Nanoimprint-induced strain engineering of two-dimensional materials

The high stretchability of two-dimensional(2D)materials has facilitated the possibility of using external strain to manipulate their properties.Hence,strain engineering has emerged as a promising technique for tailoring the performance of 2D materials by controlling the applied elastic strain field.Although various types of strain engineering methods have been proposed,deterministic and controllable generation of the strain in 2D materials remains a challenging task.Here,we report a nanoimprint-induced strain engineering(NISE)strategy for introducing controllable periodic strain profiles on 2D materials.A three-dimensional(3D)tunable strain is generated in a molybdenum disulfide(MoS_(2))sheet by pressing and conforming to the topography of an imprint mold.Different strain profiles generated in MoS_(2)are demonstrated and verified by Raman and photoluminescence(PL)spectroscopy.The strain modulation capability of NISE is investigated by changing the imprint pressure and the patterns of the imprint molds,which enables precise control of the strain magnitudes and distributions in MoS_(2).Furthermore,a finite element model is developed to simulate the NISE process and reveal the straining behavior of MoS_(2).This deterministic and effective strain engineering technique can be easily extended to other materials and is also compatible with common semiconductor fabrication processes;therefore,it provides prospects for advances in broad nanoelectronic and optoelectronic devices.

Spatial modulation of nanopattern dimensions by combining interference lithography and grayscale-patterned secondary exposure

Functional nanostructures are exploited for a variety of cutting-edge fields including plasmonics,metasurfaces,and biosensors,just to name a few.Some applications require nanostructures with uniform feature sizes while others rely on spatially varying morphologies.However,fine manipulation of the feature size over a large area remains a substantial challenge because mainstream approaches to precise nanopatterning are based on low-throughput pixel-by-pixel processing,such as those utilizing focused beams of photons,electrons,or ions.In this work,we provide a solution toward wafer-scale,arbitrary modulation of feature size distribution by introducing a lithographic portfolio combining interference lithography(IL)and grayscale-patterned secondary exposure(SE).Employed after the high-throughput IL,a SE with patterned intensity distribution spatially modulates the dimensions of photoresist nanostructures.Based on this approach,we successfully fabricated 4-inch wafer-scale nanogratings with uniform linewidths of<5%variation,using grayscale-patterned SE to compensate for the linewidth difference caused by the Gaussian distribution of the laser beams in the IL.Besides,we also demonstrated a wafer-scale structural color painting by spatially modulating the filling ratio to achieve gradient grayscale color using SE.