Continuous-wave terahertz computed tomography (THz-CT) is an important three-dimensional imaging method for probing the profile and inner properties of a sample’s structure. We applied the total variation (TV) minimization iterative algorithm to squeeze 75% data acquisition time of THz-CT without the loss of reconstruction fidelity. The imaging system is built based on a 278.6 GHz avalanche diode source. A zero-order Bessel beam is generated by an axicon, for which the intensity profile remains essentially propagation invariant within the non-diffracting zone. The effectiveness of the proposed method is verified by using three optically opaque objects. The reconstruction results show that the TV-minimization algorithm can effectively suppress noise, artefacts, and shape distortion created in sparse angle reconstruction.

Breast pseudoaneurysm is a very rare complication. In this study, we report a patient with huge breast pseudoaneurysm after ultrasound-guided vacuum-assisted biopsy (UGVAB) of breast nodules. In treatment, we used microwave ablation to treat the pseudoaneurysm, and then used UGVAB again to eliminate the complicated hematoma. The patients obtained good therapeutic effect. From this case, we experience that, before the interventional operations for breast nodules, the systematic ultrasound examination should be performed. In the needle entering channel, the obvious blood vessels should be avoided to reduce the unnecessary vascular injury. When the pseudoaneurysm occurs, the patient’s condition, pseudoaneurysm situation and hematoma size should be comprehensively considered, combined with the multidisciplinary consultation, for selecting the best treatment strategy. doi: https://doi.org/10.12669/pjms.38.1.4930 How to cite this:Cai Z, Ning R, Dong W, Zhang Y. Microwave ablation of breast pseudoaneurysm. Pak J Med Sci. 2022;38(1):---------.  doi: https://doi.org/10.12669/pjms.38.1.4930 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The progress in advanced electronic devices has imposed a great demand for developing flexible electrochemical power devices, which requires a comprehensive understanding of the mechanical-electrochemical coupling behavior of various energy storage materials. Unlike a monotonic capacitance increase of carbon-based double-layer supercapacitors, MXene-based flexible supercapacitors demonstrate a non-monotonic, i.e., "increase-then-decrease" capacitance behavior under the pressure range of 8488 kPa. This non-monotonic capacitance response to pressure is intrinsic to the MXene film as its charge storage is primarily determined by the surface activity, which can be readily affected by pressure-induced dissociation of functionalities, as well as the charge transporting kinetics as limited by the inherent layered structure. The findings described in this study not only expand the knowledge of mechanical-electrochemical coupling to layered MXenes under pressure, but also give a vital design guideline for flexible/stretchable MXene-based energy storage devices or other electronics.

With the growing demand for broadband wireless communication, high-resolution radar, security inspection, and biological analysis, terahertz (THz) technology has made significant progress in recent years. The wide applications of THz technology benefited from the rapid development of various THz functional devices. Metasurface, an essential means of manipulating THz waves, has widely been applied in multiple THz functional devices. However, it is still a great challenge to construct flexible THz metasurface devices due to the lack of flexibility of traditional semiconductor and metal materials. In this work, a two-dimensional material, MXene, is used to prepare flexible metasurfaces with frequency filtering and polarization functions. By further combining with the phase-transition-material vanadium dioxide, the VO2/MXene metasurface exhibits good performance in amplitude modulation under electrical stimulation. The modulation depth of the device reaches 86% under a lower trigger power of 11.6 mW/mm2 and the response time is only ∼100 ms. Such a flexible active metasurface with superior performance and high integration will be useful in THz imaging systems, THz sensing systems, etc.

No abstract