Experimental and theoretical analysis of organic dyes having a double D-π-A configurations for dye-sensitized solar cells

Two spiro-like organic dyes linked at the thiophene bridge (KS-11 and KS-12) together with the original rod-shaped D-π-A configuration (C1) were designed, synthesized, and characterized based on their electronic structure, and determine the photophysical and photovoltaic properties for its application in dye-sensitized solar cells. Compared to C1, the double D-π-A spiro-like configuration, which consists of two separated light-harvesting moieties, was found to be beneficial to photocurrent generation provided that they are separated properly to prevent intramolecular exciton annihilation. This was observed when KS-11, which is linked at the β-position of the thiophene moiety of D-π-A, was compared with KS-12, where the two D-π-A are linked with an additional thiophene using a α-β linkage. The results show that KS-12 produced a 20% and 17% increase in photovoltaic efficiency under simulated AM 1.5G solar irradiation compared to KS-11 and C1, respectively. This increase in photovoltaic performance is credited mostly to the reduction of recombination effects and the increase in the density of states at the semiconductor surface due to high dye loading and better charge-transfer properties

Conservative Management of Spontaneous Isolated Dissection of the Superior Mesenteric Artery

Purpose. We report the clinical outcomes of patients with spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) who were treated conservatively. Materials and Methods. A retrospective review was performed in 14 patients from 2006 to 2016 with SIDSMA. Their clinical features and computed tomographic angiography (CTA) characteristics, treatment methods, and clinical outcomes were analyzed. The mean age was 53.6 (range, 41–73) years, and the mean follow-up duration was 20.6 (range, 1–54) months. Conservative management was the primary treatment if no bowel ischemia or arterial rupture was noted. Results. The mean initial abdominal visual analog pain score was 7 (range, 5–9) in seven patients. The mean total duration of abdominal pain was 10.2 days (range, 2–42 days) in 10 patients. The mean percentage stenosis of the dissected SMA at the initial presentation was 78.8% in 14 patients. Complete obstruction of the SMA at the initial presentation was evident in 4 of the 14 patients (28.6%). Conservative management was successful in all 14 patients. None of the 14 patients developed bowel ischemia or an infarction. Abdominal pain did not recur in any patient during follow-up (mean, 20.6 months; range, 1–54 months). Conclusion. Conservative management was successful for all SIDSMA patients, even those with severe compression of the true lumen or complete obstruction of the dissected SMA

SSASS: Semi-Supervised Approach for Stenosis Segmentation

Coronary artery stenosis is a critical health risk, and its precise identification in Coronary Angiography (CAG) can significantly aid medical practitioners in accurately evaluating the severity of a patient's condition. The complexity of coronary artery structures combined with the inherent noise in X-ray images poses a considerable challenge to this task. To tackle these obstacles, we introduce a semi-supervised approach for cardiovascular stenosis segmentation. Our strategy begins with data augmentation, specifically tailored to replicate the structural characteristics of coronary arteries. We then apply a pseudo-label-based semi-supervised learning technique that leverages the data generated through our augmentation process. Impressively, our approach demonstrated an exceptional performance in the Automatic Region-based Coronary Artery Disease diagnostics using x-ray angiography imagEs (ARCADE) Stenosis Detection Algorithm challenge by utilizing a single model instead of relying on an ensemble of multiple models. This success emphasizes our method's capability and efficiency in providing an automated solution for accurately assessing stenosis severity from medical imaging data.Comment: MICCAI 2023 Conference ARCADE Challeng

MPSeg : Multi-Phase strategy for coronary artery Segmentation

Accurate segmentation of coronary arteries is a pivotal process in assessing cardiovascular diseases. However, the intricate structure of the cardiovascular system presents significant challenges for automatic segmentation, especially when utilizing methodologies like the SYNTAX Score, which relies extensively on detailed structural information for precise risk stratification. To address these difficulties and cater to this need, we present MPSeg, an innovative multi-phase strategy designed for coronary artery segmentation. Our approach specifically accommodates these structural complexities and adheres to the principles of the SYNTAX Score. Initially, our method segregates vessels into two categories based on their unique morphological characteristics: Left Coronary Artery (LCA) and Right Coronary Artery (RCA). Specialized ensemble models are then deployed for each category to execute the challenging segmentation task. Due to LCA's higher complexity over RCA, a refinement model is utilized to scrutinize and correct initial class predictions on segmented areas. Notably, our approach demonstrated exceptional effectiveness when evaluated in the Automatic Region-based Coronary Artery Disease diagnostics using x-ray angiography imagEs (ARCADE) Segmentation Detection Algorithm challenge at MICCAI 2023.Comment: MICCAI 2023 Conference ARCADE Challeng

Optimization of 4-Port Asymmetric Elliptical Birdcage RF Coil for 1.5 Tesla MRI

The elliptical whole-body radiofrequency (RF) coil can be used for RF transmission/reception in magnetic resonance (MR)-guided treatment or MR-fused system with space between the RF shield and the gradient coil available for other imaging/treatment modality. The elliptical birdcage has higher B1⁺ field uniformity than circular birdcage due to increased filling factor between the RF coil and target. In this work, the asymmetric elliptical birdcage is proposed to improve overall performance through electromagnetic simulations. This work compares the 2-port and 4-port excitations and their effects on B1⁺ field uniformity and SAR deposition for both circular and elliptical coil with symmetrical/asymmetrical structures