The features used in the separation of different objects are important for successful point cloud classification. Eigen-features from a covariance matrix of a point set with the sample mean are ...commonly used geometric features that can describe the local geometric characteristics of a point cloud and indicate whether the local geometry is linear, planar, or spherical. However, eigen-features calculated by the principal component analysis of a covariance matrix are sensitive to LiDAR data with inherent noise and incomplete shapes because of the non-robust statistical analysis. To obtain reliable eigen-features from LiDAR data and to improve classification accuracy, we introduce a method of analyzing local geometric characteristics of a point cloud by using a weighted covariance matrix with a geometric median. Each point is assigned a weight to represent its spatial contribution in the weighted principal component analysis and to estimate the geometric median which can be regarded as a localized center of a shape. In the experiments, qualitative and quantitative analyses on airborne LiDAR data and simulated point clouds show a clear improvement of the proposed method compared with the standard eigen-features. The classification accuracy is improved by 1.6–4.5% using a supervised classifier.
Cardiac hypertrophy is a common phenomenon observed in progressive heart disease associated with heart failure. Insulin‐like growth factor receptor II (IGF‐IIR) has been much implicated in myocardial ...hypertrophy. Our previous studies have found that increased activities of signaling mediators, such as calcium/calmodulin‐dependent protein kinase II (CaMKII) and calcineurin induces pathological hypertrophy. Given the critical roles played by CaMKII and calcineurin signaling in the progression of maladaptive hypertrophy, we anticipated that inhibition of CaMKII and calcineurin signaling may attenuate IGF‐IIR‐induced cardiac hypertrophy. The current study, therefore, investigated the effects of IGF‐IIR activation on the CaMKII and calcineurin signaling and whether the combinatorial inhibition of the CaMKIIδ and calcineurin signaling could ameliorate IGF‐IIR‐induced pathological hypertrophy. In the present study, we induced IGF‐IIR through the cardiomyocyte‐specific transduction of IGFIIY27L via adeno‐associated virus 2 (AAV2) to evaluate its effects on cardiac hypertrophy. Interestingly, it was observed that the activation of IGF‐IIR signaling through IGFIIY27L induces significant hypertrophy of the myocardium and increased cardiac apoptosis and fibrosis. Moreover, we found that Leu27IGF‐II significantly induced calcineurin and CaMKII expression. Furthermore and importantly, the combinatorial treatment with CaMKII and calcineurin inhibitors significantly alleviates IGF‐IIR‐induced hypertrophic responses. Thus, it could be envisaged that the inhibition of IGF‐IIR may serve as a promising candidate for attenuating maladaptive hypertrophy. Both calcineurin and CaMKII could be valuable targets for developing treatment strategies against hypertension‐induced cardiomyopathies.
Schematic representation depicting CaMKII inhibitor (KN‐93) and calcineurin inhibitor cyclosporine A (CsA) mediated inhibition of calcium/calmodulin‐dependent protein kinase II (CaMKII) and calcineurin pathways respectively.
With the rapid development of wireless communication technology, digital filters are now key components in many modern digital systems. Dual-passband digital filter is an important module of digital ...filter and has attracted wide attention. This paper proposes a novel evolutionary method to design diversified structure digital filters. Our proposed method using an adaptive multiple-elites- guide composite differential evolution algorithm, coupled with a shift mechanism (AMECoDEs) doesn’t need to use known circuit structures. Structures and parameters are evolved by crossover, mutation, and selection. Thus, our proposed method can directly design the diversified dual-passband digital filter structure and can effectively balance exploration and exploitation to prevent individuals from premature convergence. In our experiment, the connection probability, the subsystem number of the filter structure, as well as the scale factor and the crossover rate of AMECoDEs are explored to determine the optimal configuration. Compared with exiting state-of-the-art evolutionary algorithms for the design of the symmetrical and asymmetrical dual-bandpass filters, our proposed method has the smallest average passband ripple and stopband attenuation with the fastest convergence.
Due to the rapid development of digital and cloud technologies, everyone can easily shoot and spread digital videos via email or social media. However, it is difficult for law enforcement to trace ...the origin of those digital videos, while some videos or images containing illegal information such as personal privacy, obscene pornography, and national security-related content. Recently, a significant breakthrough is achieved by using Photo-Response Non-Uniformity (PRNU) noise to characterize the camera sensor. However, PRNU analysis is often carried out on a frame-by-frame basis. As a result, the processing time is unbearable when treating a large set of videos and devices. In this paper, we propose a novel video forensic method considering both cameras rolling and I-frame of videos to improve the processing time and accuracy. Experimental results demonstrate that our proposed method is at a minimum of 15 times on average faster than the most wildly used method, PRNU analysis, and reduce the false positive rate as compared to existing methods used in the field of the forensic examination.
Several approaches, including the use of small molecule acceptors, novel polymer structures, and tandem cell structures, have been adopted to prepare polymer solar cells displaying high power ...conversion efficiencies (PCEs). The application of ternary blends as the active layer for polymer solar cells—for which the absorption spectra can be tuned by varying the composition ratios of components—is another facile approach toward optimizing the PCEs of devices. The selection of suitable ternary blends active layer often relies on intuition and remains a formidable challenge. Here, we adopted a systemic approach of not only using the same donor chemical units in the two donor-acceptor (D/A) conjugated polymers with complementary light absorption (energy band gaps) but also varying the side chains architectures as a means of tuning the packing of these semi-planar conjugated polymers, thereby influencing the carrier transport and optimizing the PCE. We employed linear, branch and mixed linear-and-branch side-chain attached benzooxadiazole (BO) as the acceptor (A) units in polybenzodithiophene-thiophene-benzooxadiazole (PBDTTBO) conjugated polymers and monitored their interactions with polybenzodithiophene-fluorothienothiophene (PTB7-TH), both of which featured the same benzodithiophene (BDTT) donor (D) units. We found that incorporating a minor amount (10%) of D/A conjugated PBDTTBO with such side chains into the PTB7-TH with a fullerene allowed us to tune the packing of the two polymers and, thereby, enhance the PCEs of corresponding ternary blend devices; the PCE of the ternary blend device incorporating PBDTTBO with two branched-side chains, PTB7-TH, and PC71BM increased to 11.4% from 9.0% for the device incorporating only the binary blend of PTB7-TH and PC71BM—a relative increase of more than 25%. This approach of using side chain engineering to tune the structure of a minor conjugated polymer and, thus, influence the packing of another major conjugated polymer that features the same donor chemical units appears to be an effective means of preparing highly efficient polymer cells.
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•We use the same donor chemical units (BDTT) for tuning the packing of these semi-planar conjugated polymers.•We synthesize a series of conjugated D–π–A polymers through side chain engineering.•The optimized ternary blend device could be enhanced to 11.4% from 9.0% for the device incorporating the binary blend.•Side chain engineering appears to be an effective means of preparing highly efficient polymer cells.
In this study, we employed ternary blends capable of energy transfer—a synthesized high-band-gap small molecule (SM-4OMe) comprising benzodithiophene (BDT) and rhodanine units (a molecular structure ...that was designed for energy transfer), a low-band-gap polymer (PTB7-TH) comprising BDT and thienothiophene units with desired packing orientation, and a fullerene—as active layers for single-junction photovoltaic devices. The light absorption of the small molecule and the polymer was partially complementary, owing to their band gap difference, thereby broadening the absorption spectrum of solar light while maintaining the energy band structures that facilitated energy and charge transfer. The synthesized small molecule SM-4OMe and the PTB7-TH had somewhat similar chemical structures—with the same planar BDT donor units—and thus allowed sufficient mixing between them for energy transfer to take place. The power conversion efficiency of a device incorporating a ternary blend of PTB7-TH:SM-4OMe:PC 71 BM (0.9 : 0.1 : 1.5, w/w/w) as the active layer, processed with diiodooctane (2 vol%) in chlorobenzene, was 10.4%, which is higher than the value of 8% of the corresponding device incorporating PTB7-TH:PC 71 BM (1 : 1.5, w/w)—an increase of 30%. We attribute this enhancement to the energy transfer from the high-band-gap small molecule SM-4OMe to the low-band-gap polymer PTB7-TH and to the optimal phase-separated bulk heterojunction morphology that comprises a mean PC 71 BM cluster size of 6 nm, which is lower than 12 nm for the PTB7-TH and PC 71 BM binary blends, and slightly better in-plane packing, arising from the inducements of the presence of SM-4OMe. This approach provides a facile and effective way to enhance the power conversion efficiency of single junction organic photovoltaics.
In this paper we report the effect on the power conversion efficiency (PCE) and stability of photovoltaic devices after incorporating hydrogenated two-dimensional (2D) MoSe2 nanosheets into the ...active layer of bulk heterojunction (BHJ) organic photovoltaics (OPV). The surface properties of 2D MoSe2 nanosheets largely affect their dispersion in the active layer blend and, thus, influence the carrier mobility, PCE, and stability of corresponding devices. We treated MoSe2 nanosheets with hydrogen plasma and investigated their influence on the polymer packing and fullerene domain size of the active layer. For the optimized devices incorporating 37.5 wt% of untreated MoSe2, we obtained a champion PCE of 9.82%, compared with the champion reference PCE of approximately 9%. After incorporating the hydrogen plasma-treated MoSe2 nanosheets, we achieved a champion PCE of 10.44%—a relative increase of 16% over that of the reference device prepared without MoSe2 nanosheets. This PCE is the one of the highest ever reported for OPVs incorporating 2D materials. We attribute this large enhancement to the enhanced exciton generation and dissociation at the MoSe2–fullerene interface and, consequently, the balanced charge carrier mobility. The device incorporating the MoSe2 nanosheets maintained 70% of its initial PCE after heat-treatment at 100 °C for 1 h; in contrast, the PCE of the reference device decreased to 60% of its initial value—a relative increase in stability of 17% after incorporating these nanosheets. We also incorporated MoSe2 nanosheets (both with and without treatment) into a polymer donor (PBDTTBO)/small molecule (IT-4F) acceptor system. The champion PCEs reached 7.85 and 8.13% for the devices incorporating the MoSe2 nanosheets with and without plasma treatment, respectively—relative increases of 8 and 12%, respectively, over that of the reference. These results should encourage a push toward the implementation of transition metal dichalcogenides to enhance the performances of BHJ OPVs.
We prepared the ternary blends active layer by incorporating a new two-dimensional donor-acceptor (D/A) conjugated polymer (BDTTBO) comprising benzo-dithiophene-thiophene-thiophene-benzo oxadiazole ...chemical units that has three different conjugated side chains bithiophene (BT), benzothiophene (BzT) and thienothiophene (TT) BDTTBO-BT, BDTTBO-BzT and BDTTBO-TT into poly (benzodithiophene-fluorothienothiophene) (PTB7-TH) and PC71BM as for organic photovoltaics (OPVs). We expected that incorporating these BDTTBO with different side chains into the blend of PTB7-TH and PC71BM not only can broaden the absorption of solar spectrum thereby increasing short-circuit current density but also tune the packing of PTB7-TH and the dispersion of PC71BM. In particular, we found that incorporating 10% of BDTTBO-BT to form the PTB7-TH: BDTTBO-BT: PC71BM ternary blend (active layer) device could improve the power conversion efficiency to 10.4% from 9.0% for the binary blend of PTB7-TH: PC71BM device—a relative increase of 15%. We examined the packing orientations of the PBDTTBO: PTB7-TH:PC71BM ternary blend films using synchrotron two-dimensional grazing-incidence wide-angle X-ray scattering, and found that the incorporation of 10% relatively higher crystallinity PBDTTBO-BT, PBDTTBO-BzT or PBDTTBO-TT not only altered the packing orientation of PTB7-TH substantially but also reduced PC71BM cluster size in the ternary blend system, as compared to that in the case of PTB7-TH with PC71BM binary blend, thereby providing more pathways for electrons and thus enhancing the carrier transport in the ternary blend, as evidenced by the carrier mobility.
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•We synthesize a series of polymers with different conjugated side chains—BDTTBO-BT, BDTTBO-BzT and BDTTBO-TT.•We used BDTTBO-BT, BDTTBO-BzT and BDTTBO-TT for tuning the packing of a second conjugated polymer PTB7-TH.•The power conversion efficiency (PCE) of the optimized ternary blend device of BDTTBO-BT:PTB7-TH:PC71BM is enhanced to 10.4%.•BDTTTBO polymers presenting more flexible side-chain architectures have better interactions with the semi-planar PTB7-TH.
Optoelectronic devices consist of heterointerfaces formed between dissimilar semiconducting materials. The relative energy-level alignment between contacting semiconductors determinately affects the ...heterointerface charge injection and extraction dynamics. For perovskite solar cells (PSCs), the heterointerface between the top perovskite surface and a charge-transporting material is often treated for defect passivation
to improve the PSC stability and performance. However, such surface treatments can also affect the heterointerface energetics
. Here we show that surface treatments may induce a negative work function shift (that is, more n-type), which activates halide migration to aggravate PSC instability. Therefore, despite the beneficial effects of surface passivation, this detrimental side effect limits the maximum stability improvement attainable for PSCs treated in this way. This trade-off between the beneficial and detrimental effects should guide further work on improving PSC stability via surface treatments.
With the advances of scanning sensors and deep learning algorithms, computational pathology has drawn much attention in recent years and started to play an important role in the clinical workflow. ...Computer-aided detection (CADe) systems have been developed to assist pathologists in slide assessment, increasing diagnosis efficiency and reducing misdetections. In this study, we conducted four experiments to demonstrate that the features learned by deep learning models are interpretable from a pathological perspective. In addition, classifiers such as the support vector machine (SVM) and random forests (RF) were used in experiments to replace the fully connected layers and decompose the end-to-end framework, verifying the validity of feature extraction in the convolutional layers. The experimental results reveal that the features learned from the convolutional layers work as morphological descriptors for specific cells or tissues, in agreement with the diagnostic rules in practice. Most of the properties learned by the deep learning models summarized detection rules that agree with those of experienced pathologists. The interpretability of deep features from a clinical viewpoint not only enhances the reliability of AI systems, enabling them to gain acceptance from medical experts, but also facilitates the development of deep learning frameworks for different tasks in pathological analytics.
