RESUMO
Dielectric waveguides are capable of confining and guiding terahertz waves along sub-wavelength sized structures. A small feature size allows for a denser integration of different photonic components such as modulators, beam-splitters, wavelength (de)multiplexers and more. The integration of components on a small scale requires bending of the waveguides. In this paper we demonstrate a very short silicon 90°-bend, based on total internal reflection on an elliptically curved outer facet and a rounding of the inner corner joining two waveguides, with an average loss of 0.14 dB per bend in the 600-750 GHz range.
RESUMO
A design and multiphysical model is presented for an on-chip gas sensor that transduces terahertz gas absorption through sound generation into a mechanical motion that can be read out externally. The signal is triply enhanced by designing a structure that functions simultaneously as an optical, an acoustical and a mechanical resonator. The structure is made in high-resistivity silicon and can be fabricated using CMOS and MEMS fabrication technologies. The sensor is a purely passive element, so an external THz source and read-out are required. The chip has a footprint of 3â mm2. A detection limit of 234 ppb of methanol for a source power of 1 mW and an integration time of 1â ms is predicted.
RESUMO
Papillary fibroelastomas (PFEs) are small, slowly growing benign cardiac tumors with clinically significant risk of embolization. Surgical excision is the definitive treatment of symptomatic PFE and is conventionally performed through a median sternotomy. In this study, we report a series of 12 patients, who underwent robotic-assisted PFE removal at the Mayo Clinic. PFE involved the mitral valve, left atrium, and tricuspid valve. No major complications occurred after the procedure, and most patients were discharged 4 days after the surgery. On follow-up, 1 patient demonstrated pericarditis.
RESUMO
A 73-year-old woman presented to the emergency department with a syncopal episode and a history of dizzy spells. A transthoracic echocardiogram demonstrated a large left atrial mass extending into the right upper pulmonary veins. Subsequently, cardiac magnetic resonance imaging and coronary computed tomography angiography with three-dimensional reconstruction and printing of the heart and mass were performed, which demonstrated a high index of suspicion for an atypical left atrial myxoma. The mass was excised robotically, and the pathology report confirmed a diagnosis of myxoma.
RESUMO
An elderly female with metastatic adenocarcinoma of the lung and atrial fibrillation presented with multiple embolic strokes while on anticoagulation with Apixaban. After further investigation, a TEE showed lesions of non-bacterial thrombotic endocarditis on the mitral valve. A decision to switch the patient to LMWH for anticoagulation was then made and a follow-up TEE showed resolution of the NBTE. In this abstract, we show that heparin should remain as the anticoagulation agent of choice in the setting of NBTE associated with malignancy.
RESUMO
Cardiac tumors are rare conditions, typically diagnosed on autopsy, but with the advancement of imaging techniques they are now encountered more frequently in clinical practice. Echocardiography is often the initial method of investigation for cardiac masses and provides a quick and valuable springboard for their characterization. While some cardiac masses can be readily identified by echocardiography alone, several require incorporation of multiple data points to reach diagnostic certainty. Herein, we will provide an overview of the main clinical, diagnostic, and therapeutic characteristics of cardiac masses within the framework of their location.