Heart sound classification, used for the automatic heart sound auscultation and cardiac monitoring, plays an important role in primary health center and home care. However, one of the most difficult ...problems for the task of heart sound classification is the heart sound segmentation, especially for classifying a wide range of heart sounds accompanied with murmurs and other artificial noise in the real world. In this study, we present a novel framework for heart sound classification without segmentation based on the autocorrelation feature and diffusion maps, which can provide a primary diagnosis in the primary health center and home care. In the proposed framework, the autocorrelation features are first extracted from the sub-band envelopes calculated from the sub-band coefficients of the heart signal with the discrete wavelet decomposition (DWT). Then, the autocorrelation features are fused to obtain the unified feature representation with diffusion maps. Finally, the unified feature is input into the Support Vector Machines (SVM) classifier to perform the task of heart sound classification. Moreover, the proposed framework is evaluated on two public datasets published in the PASCAL Classifying Heart Sounds Challenge. The experimental results show outstanding performance of the proposed method, compared with the baselines.
•A novel framework for heart sound classification without segmentation.•Extracting the autocorrelation features of the normalized average Shannon energy envelopes at different wavelet sub-bands.•Fusing the autocorrelation features into the uniform features by using diffusion maps and classifying them with the SVM classifier.•Evaluating the proposed method on two public datasets published in the PASCAL Classifying Heart Sounds Challenge.
Compartmentation via filamentation has recently emerged as a novel mechanism for metabolic regulation. In order to identify filamentforming metabolic enzymes systematically, we performed a ...genome-wide screening of all strains available from an open reading frameGFP collection in Saccharomyces cerevisiae. We discovered nine novel filament-forming proteins and also confirmed those identified previously. From the 4159 strains, we found 23 proteins, mostly metabolic enzymes, which are capable of forming filaments in vivo. In silico protein-protein interaction analysis suggests that these filament-forming proteins can be clustered into several groups, including translational initiation machinery and glucose and nitrogen metabolic pathways. Using glutamine-utilising enzymes as examples, we found that the culture conditions affect the occurrence and length of the metabolic filaments. Furthermore, we found that two CTP synthases（Ura7p and Ura8p） and two asparagine synthetases（Asn1p and Asn2p） form filaments both in the cytoplasm and in the nucleus.Live imaging analyses suggest that metabolic filaments undergo sub-diffusion. Taken together, our genome-wide screening identifies additional filament-forming proteins in S. cerevisiae and suggests that filamentation of metabolic enzymes is more general than currently appreciated.
Transition-metal dichalcogenide (TMD) monolayers MXY(M=Mo,W;X≠Y=S,Se,Te) are two-dimensional polar semiconductors. Setting the WSeTe monolayer as an example and using density functional theory ...calculations, we investigate the manipulation of Rashba spin-orbit coupling (SOC) in the MXY monolayer. It is found that the intrinsic out-of-plane electric field due to the mirror symmetry breaking induces the large Rashba spin splitting around the Γ point, which, however, can be easily tuned by applying the in-plane biaxial strain. Through a relatively small strain (from −2% to 2%), a large tunability (from around −50% to 50%) of Rashba SOC can be obtained due to the modified orbital overlap, which can in turn modulate the intrinsic electric field. The orbital selective external potential method further confirms the significance of the orbital overlap between W−dz2 and Se−pz in Rashba SOC. In addition, we also explore the influence of the external electric field on Rashba SOC in the WSeTe monolayer, which is less effective than strain. By calculating the electric-field-induced Rashba SOC in all six MX2 monolayers, the rule of the electric-field influence on Rashba SOC in TMD monolayers is demonstrated. The large Rashba spin splitting, together with the valley spin splitting in MXY monolayers, may make a special contribution to semiconductor spintronics and valleytronics.
Objective
To construct and validate a deep convolutional neural network (DCNN)‐based artificial intelligence (AI) system for the detection of nasopharyngeal carcinoma (NPC) using archived ...nasopharyngoscopic images.
Methods
We retrospectively collected 14107 nasopharyngoscopic images (7108 NPCs and 6999 noncancers) to construct a DCNN model and prepared a validation dataset containing 3501 images (1744 NPCs and 1757 noncancers) from a single center between January 2009 and December 2020. The DCNN model was established using the You Only Look Once (YOLOv5) architecture. Four otolaryngologists were asked to review the images of the validation set to benchmark the DCNN model performance.
Results
The DCNN model analyzed the 3501 images in 69.35 s. For the validation dataset, the precision, recall, accuracy, and F1 score of the DCNN model in the detection of NPCs on white light imaging (WLI) and narrow band imaging (NBI) were 0.845 ± 0.038, 0.942 ± 0.021, 0.920 ± 0.024, and 0.890 ± 0.045, and 0.895 ± 0.045, 0.941 ± 0.018, and 0.975 ± 0.013, 0.918 ± 0.036, respectively. The diagnostic outcome of the DCNN model on WLI and NBI images was significantly higher than that of two junior otolaryngologists (p < 0.05).
Conclusion
The DCNN model showed better diagnostic outcomes for NPCs than those of junior otolaryngologists. Therefore, it could assist them in improving their diagnostic level and reducing missed diagnoses.
Level of Evidence
3 Laryngoscope, 134:127–135, 2024
The deep convolutional neural network model can improve the diagnosis level of junior endoscopists, and also lays the foundation for the application of artificial intelligence‐assisted endoscopic diagnosis of nasopharyngeal cancer.
Microwave helped to obtain higher purity cellulose under the same reaction conditions, which indicated the important role of the non-thermal effects of microwave.
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•Cellulose with high ...purity was obtained from wheat straw through microwave-assisted hydrolysis.•Temperature proved to be the most important reaction parameter for cellulose isolation during the process.•Non-thermal effect of microwave was confirmed and discussed.•Microwave could reduce approximately 50 %–75 % of the reaction duration or 67 % of the chemical consumption.•Various composition determination methods were employed to compare the contribution of reaction conditions.
Microwave-assisted hydrolysis has been widely studied for cellulose fiber isolation, but the influence of reaction conditions and the microwave non-thermal effect are not well clarified. In this study, a series of well-designed experiments were carried out to measure the effects of reaction conditions including temperature, duration and alkali concentration. Compared to the other parameters, temperature was more relevant to the cellulose content in fiber. It could reach the maximum purity of 90.66 % when the temperature was up to 140 °C. Moreover, the existence of non-thermal effect of microwave has been confirmed through extensive determination and characterization of the fibers obtained from parallel controlled experiments conducted with or without microwave assistance. Approximately 50 %–75 % reduction in reaction time or 67 % of that in chemical costs would be realized under microwave with respect to traditional heating hydrolysis. Therefore, this work provides both deep insight and efficiency strategy into the microwave-assisted cellulose isolation.
The simple hydrothermal self‐assembly of metal ions, 5,5′‐(4,5‐dicarboxy‐1,2‐phenylene)bis(oxy)diisophthalic acid (L1'), and N2H4·H2O at pH = 8 (adjusted by oxalic acid) created two new ...acylhydrazinetetracarboxylate‐extended 3‐D Sr2+ and Ba2+ coordination polymers Sr2(HL1)(H2O) (H5L1 = 5,5′‐(1,4‐dioxo‐1,2,3,4‐tetrahydrophthalazine‐6,7‐diyl)bis(oxy)diisophthalic acid) 1 and Ba5(HL1)2(ox)(H2O)2·6H2O·N2H4 (ox = oxalate) 2. H5L1 originated from the in situ acylation of L1′ with N2H4. X‐ray single‐crystal diffraction analysis reveals that (i) the 3‐D network of 1 is based on a rod‐like secondary building unit (SBU), which can be described as an alternate arrangement of two types of dinuclear Sr‐O clusters; (ii) the 3‐D network of 2 is also based on a rod‐like SBU. The different is that the SBU for 2 can be described as an alternate arrangement of a kind of trinuclear cluster and a kind of tetranuclear cluster. Both 1 and 2 emit blue light. With regard to their good photoluminescence properties, their trinitrophenol (TNP) sensing ability was investigated. The results indicate that both can selectively detect TNP. The quenching constants Ksv are calculated to be 3.21 × 104 m–1 for 1 and 2.98 × 104 m–1 for 2, respectively.
Structures of two new acylhydrazinetetracarboxylate‐extended 3‐D Sr2+ and Ba2+ coordination polymers are reported. In view of their photoluminescence properties, their sensing abilities for TNP were investigated.
A series of CuO/CeO2 and inverse CeO2/CuO catalysts were prepared by an incipient wetness impregnation method and tested for CO oxidation. Crystallite sizes of CeO2 and CuO were evaluated by X-ray ...diffraction and N2O chemisorption, as well as transmission electron microscopy. It was found that a CuO(5)/CeO2-500 catalyst with a CuO crystallite size of 4.1 nm and a CeO2(5)/CuO-500 catalyst with a CeO2 crystallite size of 4.0 nm had identical activities, indicating that the reaction may occur at the interface of CuO−CeO2. According to the turnover frequency based on CuO sites located on the CuO−CeO2 interface, the activity on the larger CuO crystallite was much higher than that on the smaller one, indicating that CuO−CeO2 catalyst for CO oxidation is structure-sensitive. The enhanced activity was ascribed to a higher density of chemisorbed CO on the active sites for the larger CuO crystallite.
Pd/ZnO catalysts with ca. 2 wt.% Pd loading employing ZnO nanocrystals with various morphologies as supports, including ZnO nanoplates (p−ZnO) predominantly exposing polar {002} facets, ZnO nanorods ...(r−ZnO) predominantly exposing nonpolar {100} and {101} facets, and commercial ZnO (c−ZnO) exposing random facets, have been prepared as catalysts for the catalytic reaction of CO2 hydrogenation into formic acid (FA) without the addition of base under mild conditions. A remarkable morphology‐dependence of zinc oxide in the Pd/ZnO catalysts was observed. Catalytic activities of various Pd/ZnO catalysts in CO2 hydrogenation into FA follow an order of Pd/r−ZnO>Pd/p−ZnO>Pd/c−ZnO, and all the catalysts are stable. Kinetic study, CO2‐TPD analysis, and in situ DRIFTS spectra provide evidence that all the Pd/ZnO catalysts follow a similar catalytic mechanism that CO2 activation is the rate‐determining step. Consequently, r−ZnO, possessing a higher density of weak basic sites than p−ZnO and c−ZnO, can act as a superb support to prepare Pd/r−ZnO catalyst, which is more active than Pd/p−ZnO and Pd/c−ZnO catalysts for the production of FA. These findings nicely demonstrate the crystal‐plane engineering of the metal oxide support in tuning the catalytic performance of Pd‐based catalysts for CO2 hydrogenation into FA.
CO2 transformation: This paper comprehensively elucidated the ZnO morphology‐dependent Pd/ZnO catalysis in base‐free CO2 hydrogenation into formic acid under mild conditions.
Schematic diagram of the differences in crotonaldehyde adsorption/hydrogenation on Ir NPs and IrFe alloy and thus the catalytic performance.
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•IrFe alloy was more active and selective ...than Ir NPs in the hydrogenation of crotonaldehyde.•Catalytic performance of the IrFe alloy was related to its electronic structure.•Ir-Fe pair provided adsorption site for C = O group in crotonaldehyde.•Adsorption of crotonaldehyde was much enhanced on IrFe alloy and thus improved activity.•Hydrogenation of C = O bond was easier on IrFe alloy and thus improved selectivity.
IrFe alloy nanoparticles with different Ir/Fe molar ratios were synthesized and exhibited good performance in the gas phase selective hydrogenation of crotonaldehyde (CRAL). The IrFe alloy with an Ir/Fe ratio of 19/1 gave a turnover frequency (TOF) of 0.022 s−1 at 80 °C and a crotyl alcohol (CROL) selectivity of 91 %, while the bare Ir/BN catalyst gave a TOF of 0.0014 s−1 and a CROL selectivity of 74 %. Detailed characterizations, kinetic investigation, and in situ spectroscopic study revealed that the altered electronic structure of the IrFe alloy with transfer from Fe to Ir species was essential for its improved performance. Also, density functional theory calculations indicated that such an electronic structure resulted in strong CRAL interaction with the Ir-Fe entity, thus higher adsorption capacity and lower reaction barrier than that on the Ir-Ir counterpart, which accounted for the higher activity. Moreover, the hydrogenation of C = O bond required lower barrier on the Ir-Fe site than that on the Ir-Ir, which well explained the higher selectivity to CROL.
The path following control under disturbance was studied for an underactuated unmanned surface vehicle (USV) subject to the rudder angle and velocity constraints. For this reason, a variable ...look-ahead integral line-of-sight (LOS) guidance law was designed on the basis of the disturbance estimation and compensation, and a cascade path following control system was created following the heading control law based on the model prediction. Firstly, the guidance law was designed using the USV three-degree-of-freedom (DOF) motion model and the LOS method, while the tracking error state was introduced to design the real-time estimation of disturbance observer and compensate for the influence of ocean current. Moreover, the stability of the system was analyzed. Secondly, sufficient attention was paid to the rudder angle and velocity constraints and the influence of system delay and other factors in the process of path following when the heading control law was designed with the USV motion response model and the model predictive control (MPC). The moving horizon optimization strategy was adopted to achieve better dynamic performance, effectively overcome the influence of model and environmental uncertainties, and further prove the stability of the control law. Thirdly, a simulation experiment was carried out to verify the effectiveness and advancement of the proposed algorithm. Fourthly, the "Sturgeon 03" USV was used in the lake test of the proposed control algorithm to prove its feasibility in the engineering practices.
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