Level set methods have been widely used to implement active contours for image segmentation applications due to their good boundary detection accuracy. In the context of medical image segmentation, ...weak edges and inhomogeneities remain important issues that may hinder the accuracy of any segmentation method based on active contours implemented using level set methods. This paper proposes a method based on active contours implemented using level set methods for segmentation of such medical images. The proposed method uses a level set evolution that is based on the minimization of an objective energy functional whose energy terms are weighted according to their relative importance in detecting boundaries. This relative importance is computed based on local edge features collected from the adjacent region located inside and outside of the evolving contour. The local edge features employed are the edge intensity and the degree of alignment between the image's gradient vector flow field and the evolving contour's normal. We evaluate the proposed method for segmentation of various regions in real MRI and CT slices, X-ray images, and ultra sound images. Evaluation results confirm the advantage of weighting energy forces using local edge features to reduce leakage. These results also show that the proposed method leads to more accurate boundary detection results than the state-of-the-art edge-based level set segmentation methods, particularly around weak edges.
Nowadays, organic solar cells (OSCs) with Y6 and its derivatives as electron acceptors provide the highest efficiencies among the studied binary OSCs. To further improve the performances of OSCs, the ...fabrication of ternary OSCs (TOSCs) is a convenient strategy. Essentially, morphology control and the trade-off between voltage and photocurrent are the main critical issues in TOSCs. Herein, we address these problems by constructing TOSCs where an alloy-like composite is formed between Y6 and a newly designed derivative, BTP-M. Employing an electron-pushing methyl substituent as a replacement for the electron-withdrawing F atoms on Y6, BTP-M shows higher energy levels and lower crystallinity than Y6. As a result, the obtained Y6:BTP-M alloy can simultaneously optimize energy levels to reduce energy loss as well as the morphologies of the active layers to favor photocurrent generation, leading to an enhanced open-circuit voltage (
V
oc
) of 0.875 V together with a larger short-circuit current density (
J
sc
) of 26.56 mA cm
−2
for TOSCs based on the polymer donor PM6 and Y6:BTP-M acceptor alloy. Consequently, a best efficiency of 17.03% is achieved for the corresponding TOSCs, which is among the best values for single-junction OSCs. In addition, our TOSCs also exhibit good thickness tolerance, and can reach 14.23% efficiency even though the active layer is as thick as 300 nm.
An alloy-like model based on Y6 and its derivative BTP-M is constructed to fabricate ternary organic solar cells, leading to a best efficiency of 17.03%.
Abstract
Background
Acute pancreatitis is a common and potentially lethal gastrointestinal disease, but literatures for the disease burden are scarce for many countries. Understanding the current ...burden of acute pancreatitis and the different trends across various countries is essential for formulating effective preventive intervenes. We aimed to report the incidence, mortality, and disability-adjusted life-years (DALYs) caused by acute pancreatitis in 204 countries and territories between 1990 and 2019.
Methods
Estimates from the Global Burden of Disease Study 2019 (GBD 2019) were used to analyze the epidemiology of acute pancreatitis at the global, regional, and national levels. We also reported the correlation between development status and acute pancreatitis’ age-standardized DALY rates, and calculated DALYs attributable to alcohol etiology that had evidence of causation with acute pancreatitis. All of the estimates were shown as counts and age-standardized rates per 100,000 person-years.
Results
There were 2,814,972.3 (95% UI 2,414,361.3–3,293,591.8) incident cases of acute pancreatitis occurred in 2019 globally; 1,273,955.2 (1,098,304.6–1,478,594.1) in women and 1,541,017.1 (1,307,264.4–1,814,454.3) in men. The global age-standardized incidence rate declined from 37.9/100,000 to 34.8/100,000 during 1990–2019, an annual decrease of 8.4% (5.9–10.4%). In 2019, there were 115,053.2 (104,304.4–128,173.4) deaths and 3,641,105.7 (3,282,952.5–4,026,948.1) DALYs due to acute pancreatitis. The global age-standardized mortality rate decreased by 17.2% (6.6–27.1%) annually from 1.7/100,000 in 1990 to 1.4/100,000 in 2019; over the same period, the age-standardized DALY rate declined by 17.6% (7.8–27.0%) annually. There were substantial differences in the incidence, mortality and DALYs across regions. Alcohol etiology attributed to a sizable fraction of acute pancreatitis-related deaths, especially in the high and high-middle SDI regions.
Conclusion
Substantial variation existed in the burden of acute pancreatitis worldwide, and the overall burden remains high with aging population. Geographically targeted considerations are needed to tailor future intervenes to relieve the burden of acute pancreatitis in specific countries, especially for Eastern Europe.
Low energy loss and efficient charge separation under small driving forces are the prerequisites for realizing high power conversion efficiency (PCE) in organic photovoltaics (OPVs). Here, a new ...molecular design of nonfullerene acceptors (NFAs) is proposed to address above two issues simultaneously by introducing asymmetric terminals. Two NFAs, BTP‐S1 and BTP‐S2, are constructed by introducing halogenated indandione (A1) and 3‐dicyanomethylene‐1‐indanone (A2) as two different conjugated terminals on the central fused core (D), wherein they share the same backbone as well‐known NFA Y6, but at different terminals. Such asymmetric NFAs with A1‐D‐A2 structure exhibit superior photovoltaic properties when blended with polymer donor PM6. Energy loss analysis reveals that asymmetric molecule BTP‐S2 with six chlorine atoms attached at the terminals enables the corresponding devices to give an outstanding electroluminescence quantum efficiency of 2.3 × 10−2%, one order of magnitude higher than devices based on symmetric Y6 (4.4 × 10−3%), thus significantly lowering the nonradiative loss and energy loss of the corresponding devices. Besides, asymmetric BTP‐S1 and BTP‐S2 with multiple halogen atoms at the terminals exhibit fast hole transfer to the donor PM6. As a result, OPVs based on the PM6:BTP‐S2 blend realize a PCE of 16.37%, higher than that (15.79%) of PM6:Y6‐based OPVs. A further optimization of the ternary blend (PM6:Y6:BTP‐S2) results in a best PCE of 17.43%, which is among the highest efficiencies for single‐junction OPVs. This work provides an effective approach to simultaneously lower the energy loss and promote the charge separation of OPVs by molecular design strategy.
Asymmetric electron acceptors, by combining halogenated indandione and 3‐dicyanomethylene‐1‐indanone as two different conjugated terminals, are designed and synthesized. Such design enables reduced energy loss and boosts charge separation, thus leading to 16.37% binary organic photovoltaics (OPVs) and 17.43% ternary OPVs, which are among the best efficiencies for single‐junction OPVs.
Fullerene‐free OSCs employing n‐type small molecules or polymers as the acceptors have recently experienced a rapid rise with efficiencies exceeding 12%. Owing to the good optoelectronic and ...morphological tunabilities, non‐fullerene acceptors exhibit great potential for realizing high‐performance and practical OSCs. In this Review, recent exciting progress made in developing highly efficient non‐fullerene acceptors is summarized, mainly correlating factors like absorption, energy loss and morphology of new materials to their correspondent photovoltaic performance.
Fullerene‐free organic solar cells (OSCs) have made great progress in recent years with efficiencies surpassing 12%. In this Review, recent high‐performance non‐fullerene acceptors developed for OSCs are summarized, mainly correlating factors like absorption, energy loss and morphology of new materials to their correspondent photovoltaic performance. The perspectives for fullerene‐free OSCs with efficiency of 15% are briefly discussed.
High‐performance organic solar cells (OSCs) at the current stage are majorly accomplished from the processing of halogenated solvents, such as chloroform, which will be constrained for upscale ...fabrication due to the adverse health and environmental impacts. Therefore, exploring the high‐performance OSCs from non‐halogenated solvent processing becomes highly necessary, yet largely lagged behind. Herein, it is demonstrated high‐performance OSCs can be obtained from the hot spin processing of different non‐halogenated solvents, and achieve the highest reported efficiency of OSCs from non‐halogenated solvent processing so far. It is revealed that the phase evolution of ternary blends during solution‐to‐solid transition has a correlation to the substrate temperature. With the elevated substrate temperature of hot spin coating, the optimal blend films can be secured in different kinds of non‐halogenated solvents. As result, high‐performance OSCs are obtained with excellent power conversion efficiencies of 18.25% in o‐xylene, 18.20% in p‐xylene, and 18.12% in toluene, respectively. To the author's best knowledge, these results represent the best‐performed OSCs made from non‐halogenated solvents so far.
High‐performance organic solar cells (OSCs) are feasibly obtained from the hot spin coating of different kinds of non‐halogenated solvents. It is revealed that the blend phase evolution during solution‐to‐solid transition has a correlation to the substrate temperature. As result, high‐performance OSCs are obtained with power conversion efficiencies of 18.25% in o‐xylene, 18.20% in p‐xylene, and 18.12% in toluene, respectively.
Searching the cost‐effective organic semiconductors is strongly needed in order to facilitate the practice of organic solar cells (OSCs), yet to be fulfilled. Herein, we have succeeded in developing ...two non‐fused ring electron acceptors (NFREAs), leading to the highest efficiency of 16.2 % for the NFREA derived OSCs. These OSCs exhibit the superior operational stabilities under one sun equivalent illumination without ultraviolet (UV) filtration. It is revealed that the modulation of halogen substituents on aromatic side chains, as the new structural tool to tune the intermolecular interaction and optoelectronic properties of acceptors, not only promotes the interlocked tic‐tac‐toe frame of three‐dimensional stacks in solid, but also improves charge dynamics of acceptors to enable high‐performance and stable OSCs.
Two non‐fused ring electron acceptors (NFREAs) have been developed. The halogen substituents on the aromatic side chains, as the new structure design tools, not only facilitate the construction of 3D stacks in solid, but also optimize the optoelectronic properties of the NFREAs, leading to organic solar cells with 16.2 % efficiency and excellent operational stability.
Speech emotion recognition (SER) is a challenging task, since the definition of emotions in sentences is ambiguous. Previous research work mainly focuses on extracting hand-craft features from audio ...signals to feed into shallow models. Recently, Visual Geometry Group like(VGGish) has replaced traditional feature extractors, due to its effects. VGGish feature vectors were viewed as Deep Neural Network (DNN) selected from a number of features. Although the existing studies on SER have achieved promising results, they only use single-level features. This paper proposes an emotion recognition system, based on speech signals, using two-level features with position information, L ater F eature F usion with V GGish O verlap(LFFVO), to tackle the present limitations. First, the position information, from two-level features, is extracted by Bi-direction Long Short Time Memory (BiLSTM) neural network, followed by features fusion, to predict the emotion. The proposed method improved accuracy from 48.2% (baseline) to 69.5%, when trained, validated and evaluated using an Interactive emotional dyadic motion capture database (IEMOCAP).
Clean energy production and saving play vital impacts on the sustainability of the global community. Herein, high‐performance semitransparent organic solar cells (ST‐OSCs) with excellent features of ...power generation, being see‐through, and infrared reflection of heat dissipation, with promising perspectives for building‐integrated photovoltaics (BIPVs) are reported. To simultaneously improve average visible transmittance (AVT) and power conversion efficiency (PCE), formally in a trade‐off relationship, of ST‐OSCs, new ternary blends with alloy‐like near‐infrared (NIR) acceptors are employed, which are effective to improve device efficiency while maintaining visible absorption unchanged, resulting in PCEs of 16.8% for opaque devices and 13.1% for semitransparent OSCs (AVT of 22.4% and infrared photon radiation rejection (IRR) of 77%). Further, multifunctional ST‐OSCs are realized via introducing simple, yet effective photonic reflectors, together with optical simulation, leading to not only perfect fitting of the visible transmittance peak (555 nm) to the photopic response of the human eye but also an excellent IRR of 90% (780–2500 nm), along with 23% AVT and over 12% PCE. This is thought to be the best‐performing multifunctional ST‐OSC with promising prospects as BIPVs in terms of power generation, heat dissipation, and being see‐through.
High‐performance semitransparent organic solar cells are achieved through combined design efforts on the formulation of near‐infrared ternary blends and optical control over photonic reflectors, which exhibit excellent features of power generation, they being see‐through, and infrared reflection.
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