Development of Sn-doped ZnO based ecofriendly piezoelectric nanogenerator for energy harvesting application.

In this work, we have a demonstrated zinc oxide (ZnO) polymer-based ecofriendly piezoelectric nanogenerator (PENG) on a paper substrate for an energy harvesting application. The ZnO thin film is developed on the paper substrate, where different doping concentrations of Sn have been investigated systematically to validate the effect of doping towards enhancing the device performance. The piezoelectric potential of the fabricated device is evaluated by applying three different loads (4 N, 8 N, 22 N), where the source of the corresponding mechanical loads is based on the object of a musical drum stick. The results suggest that the pristine ZnO PENG device can generate a maximum output voltage and current of 2.15 V and 17 nA respectively. Moreover, the ZnO PENG device doped with 2.5% Sn achieved an even higher voltage (4.15 V) and current (36 nA) compared to pristine ZnO devices. In addition, the hydrothermal growth technique used to develop Sn-doped ZnO has the benefits of high scalability and low cost. Hence, the Sn-doped PENG device is a suitable candidate for energy harvesting applications operating in both uniform and non-uniform loading conditions.

Breast tumor parameter estimation and interactive 3D thermal tomography using discrete thermal sensor data.

This work uses a simple low-cost wearable device embedded with discrete thermal sensors to map the breast skin surface temperature. A methodology has been developed to estimate diameter, blood perfusion, metabolic heat generation and location in X, Y, Z coordinate of tumor from this discrete set of data. An interactive 3D thermal tomography was developed which provides a detailed 3D thermal view of the breast anatomy. Using this system, the user can interactively rotate and slice the 3D thermal image of the breast for a detailed study of the tumor. Finite element method (FEM) and an evolution-based inverse method were used for the parameter estimation. The method was first validated using phantom experiments and the results obtained were within an error of 10% (0.005 W cm-3) for heat generation and 15% (0.3 cm) for heater location. Further validation was carried out through clinical trials on 60 human subjects. Estimated blood perfusion rate and metabolic heat generation rate exhibit distinguishable difference between cancerous and non-cancerous breast. Estimated diameter and location of tumor in cancerous breast shows good agreement with the actual clinical reports. We have obtained a sensitivity of 82.78% and specificity of 87.09%. Proposed breast tumor parameter estimation methodology with interactive 3D thermal tomography is a good screening tool for breast cancer detection and also useful for clinicians to find out location including depth.

Laparoscopic derotation and cholecystectomy for torsion gallbladder.

Torsion of the gallbladder is an unusual cause of gangrenous cholecystitis. Even with the advent of recent radiological imaging modalities, the preoperative diagnosis of this entity remains elusive. Herein, we present a case of gallbladder torsion in a 76-year-old lady who successfully underwent laparoscopic derotation and cholecystectomy.

Laparoscopic removal of an artery forceps.

Numerous foreign bodies, such as surgical gauze, pads and instruments, and other items, have been left behind in the abdominal cavity during open surgeries. These have been traditionally removed at redo open surgeries. Here we describe a case of an artery forceps left behind at a previous surgery (open cholecystectomy and appendicectomy) performed 5 years earlier that was removed by laparoscopy.