To improve the lubrication conditions of the seal in the pharmaceutical kettles, a specific shape groove with micrometer level on the sealing end face is set up to fully utilize the fluid dynamic ...pressure effect under given working conditions. A numerical model is developed to solve the pressure distribution in the micro groove, where any groove shape can be used. The numerical form of the model is derived using the principle of mass conservation without considering the film thickness derivative term, and the coordinate transformation is introduced to adapt to the curved shape of the groove. The cavitation phenomenon is taken into account in the flow field of the seal, and the JFO cavitation model is introduced to modify the Reynolds equation. The diversity of groove shapes is considered, and the node adsorption method is adopted to approximate the groove shape. The model is established based on the principle of mass conservation, which can adapt to any different groove shapes and has a strong scalability. By mathematical modeling and solving, the performances of the micro groove seal under different groove shapes are analyzed, providing a basis for the micro groove design of seal in pharmaceutical kettles.
The fabrication of a flexible thermoelectric generator (TEG) with both high power output and good flexibility has drawn considerable attention. Solution-processed inorganic nanocrystals have good ...processibility in interface to retain excellent electrical properties of nanocrystals and can be processed into thin films on a flexible substrate by an easy scale-up printing or coating method. However, a high-performance TEG device based on inorganic solution-processed materials also poses challenges when it comes to flexibility of the whole device. Herein, flexible planar TEG devices are fabricated by printing an ink mixture comprising solution-processed bismuth telluride (Bi
2
Te
3
) nanoplates with reduced-graphene oxide (rGO) nanosheets onto flexible polyimide substrates. The interface treatment by hot ethylenediamine and the appropriate amount of rGO contribute to the high electrical properties of the material. Also, when rGO nanosheets of 1% mass ratio are added, the optimum power output of the corresponding rGO/Bi
2
Te
3
TEG device with six elements reaches ∼1.72 μW at a temperature difference of 20 K. Moreover, owing to the contribution from flexible rGO nanosheets, the suitable thickness of each element, and the artful connection of elements with a soft copper wire in the devices, the 1% rGO/Bi
2
Te
3
TEG device was found to be robust, and its electrical resistance merely changes by 2% after bending 1000 cycles on 5 mm in bending. These inorganic-based TEGs with both high performance and good flexibility will promote the development of new generation energy devices in the field of flexible electronics.
The 1% rGO/Bi
2
Te
3
composite-based flexible six-element planar thermoelectric generator devices possess both high power output and significant flexibility, which will greatly promote the application of functional inorganic materials into flexible electronics.
Fully convolutional neural networks have achieved great success in salient object detection, in which the effective use of multi‐layer features plays a critical role. Based on this advantage, many ...saliency detectors have emerged in recent years, and most of them designed a series of network structures to integrate the multi‐level features generated by the backbone network. However, information in different layer play different roles in saliency object detection, how to integrate them effectively is still a great challenge. In this article, a selective feature fusion network which consists of a selective feature fusion module (SFM) and an attention‐guide hierarchical feature emphasis module (AEM) is proposed. Most of the previous works mainly integrate multi‐level feature by addition and concatenation, as a difference, SFM adaptively selects the important information from the input features in the fusion, which effectively avoids introducing too much redundant information. Besides, AEM combines spatial attention and channel attention to enhance features simply and effectively by hierarchical iteration, and further improve the accuracy of salient object detection. Experiments on five datasets show that the proposed selective feature fusion method achieve satisfactory results when comparing to other state‐of‐the‐art salient object detection approaches.
In this paper, we propose a selective feature fusion network which consists of a selective feature fusion module (SFM) and an attention‐guide hierarchical feature emphasis module (AEM). Selective feature fusion modules adaptively selects the important information from the input features in the fusion, which effectively avoids introducing too much redundant information. Attention‐guide hierarchical feature emphasis module combines spatial attention and channel attention to enhance features simply and effectively by hierarchical iteration, and further improve the accuracy of salient object detection.
Fully convolutional neural networks‐based salient object detection has recently achieved great success with its performance benefits from the effective use of multi‐layer features. Based on this, ...most of the existing saliency detectors designed complex network structures to fuse the multi‐level features generated by the backbone network. However, the variable scale and complex shape of the target are always a great challenge for saliency detection tasks. In this paper, the authors propose a Rich‐scale Feature Fusion Network (RFFNet) for salient object detection. The authors design a rich‐scale feature interactive fusion module to obtain more efficient features from the multi‐scale features. Moreover, the global feature enhance module is used to extract features with better characterization for the final saliency prediction. Extensive experiments performed on five benchmark datasets demonstrate that the proposed method can achieve satisfactory results on different evaluation metrics compared to other state‐of‐the‐art salient object detection approaches.
Although the video surveillance system plays an important role in intelligent transportation, the limited camera views make it difficult to observe many traffic events. In this paper, we collect and ...combine the traffic flow variables from the multi-source sensors, and propose a PITED method based on Random Forest (RF) and Permutation importance (PI) for traffic event detection. This model selects the suitable traffic flow variables by means of permutation arrangement of importance, and establishes the whole process of acquisition, preprocessing, quantization, modeling and evaluation. Moreover, the real traffic data are collected and tested in this paper for evaluating the experiment performance, including the miss/false rate of traffic event, and average detection time. The experimental results show that the detection rate is more than 85% and the false alarm rate is less than 3%. It means the model is effective and efficient in the practical application regardless of both workdays and holidays.
The dynamics of quasispecies afford RNA viruses a great fitness on cell tropism and host range. To study the quasispecies features and the intra-host evolution of SARS-CoV-2, we collected nine ...confirmed patients and sequenced the haplotypes of spike gene using a single-molecule real-time platform. Fourteen samples were extracted from sputum, nasopharyngeal swabs, or stool, which in total produced 283,655 high-quality circular consensus sequences. We observed a stable quasispecies structure that one master mutant (mean abundance ∼0.70), followed by numerous minor mutants (mean abundance ∼1.21 × 10−3). Under high selective pressure, minor mutants may obtain a fitness advantage and become the master ones. The later predominant substitution D614G existed in the minor mutants of more than one early patient. An epidemic variant had a possibility to be independently originated from multiple hosts. The mutant spectrums covered ∼85% amino acid variations of public genomes (GISAID; frequency ≥ 0.1) and likely provided an advantage mutation pool for the current/future epidemic variants. Notably, 32 of 35 collected antibody escape substitutions were preexistent in the early quasispecies. Virus populations in different tissues/organs revealed potentially independent replications. The quasispecies complexity of sputum samples was significantly lower than that of nasopharyngeal swabs (P = 0.02). Evolution analysis revealed that three continuous S2 domains (HR1, CH, and CD) had undergone a positive selection. Cell fusion-related domains may play a crucial role in adapting to the intrahost immune system. Our findings suggested that future epidemiologic investigations and clinical interventions should consider the quasispecies information that has missed by routine single consensus genome. IMPORTANCE RNA virus population in a host does not consist of a consensus single haplotype but rather an ensemble of related sequences termed quasispecies. The dynamics of quasispecies afford SARS-CoV-2 a great ability on genetic fitness during intrahost evolution. The process is likely achieved by changing the genetic characteristics of key functional genes, such as the spike glycoprotein. Previous studies have applied the next-generation sequencing (NGS) technology to evaluate the quasispecies of SARS-CoV-2, and results indicated a low genetic diversity of the spike gene. However, the NGS platform cannot directly obtain the full haplotypes without assembling, and it is also difficult to predict the extremely low-frequency variations. Therefore, we introduced a single-molecule real-time technology to directly obtain the haplotypes of the RNA population and further study the quasispecies features and intrahost evolution of the spike gene.
Host genetic factors such as single nucleotide variations may play a crucial role in the onset and progression of HBV-related acute-on-chronic liver failure (ACLF). However, the underlying genomic ...copy number variations (CNVs) involved in the pathology are currently unclear.
We genotyped two cohorts with 389 HBV-related ACLF patients and 391 asymptomatic HBV carriers (AsCs), and then carried out CNV-based global burden analysis and a genome-wide association study (GWAS).
For 1874 rare CNVs, HBV-related ACLF patients exhibited a high burden of deletion segments with a size of 100-200 kb (P value = 0.04), and the related genes were significantly enriched in leukocyte transendothelial migration pathway (P value = 4.68 × 10
). For 352 common CNVs, GWAS predicted 17 significant association signals, and the peak one was a duplication segment located on 1p36.13 (~ 38 Kb, P value = 1.99 × 10
, OR = 2.66). The associated CNVs resulted in more copy number of pro-inflammatory genes (MST1L, DEFB, and HCG4B) in HBV-related ACLF patients than in AsC controls.
Our results suggested that the impact of host CNV on HBV-related ACLF may be through decreasing natural immunity and enhancing host inflammatory response during HBV infection. The findings highlighted the potential importance of gene dosage on excessive hepatic inflammation of this disease.
Persistent transcription of HBV covalently closed circular DNA (cccDNA) is critical for chronic HBV infection. Silencing cccDNA transcription through epigenetic mechanisms offers an effective ...strategy to control HBV. Long non‐coding RNAs (lncRNAs), as important epigenetic regulators, have an unclear role in cccDNA transcription regulation. In this study, lncRNA sequencing (lncRNA seq) is conducted on five pairs of HBV‐positive and HBV‐negative liver tissue. Through analysis, HOXA‐AS2 (HOXA cluster antisense RNA 2) is identified as a significantly upregulated lncRNA in HBV‐infected livers. Further experiments demonstrate that HBV DNA polymerase (DNA pol) induces HOXA‐AS2 after establishing persistent high‐level HBV replication. Functional studies reveal that HOXA‐AS2 physically binds to cccDNA and significantly inhibits its transcription. Mechanistically, HOXA‐AS2 recruits the MTA1‐HDAC1/2 deacetylase complex to cccDNA minichromosome by physically interacting with metastasis associated 1 (MTA1) subunit, resulting in reduced acetylation of histone H3 at lysine 9 (H3K9ac) and lysine 27 (H3K27ac) associated with cccDNA and subsequently suppressing cccDNA transcription. Altogether, the study reveals a mechanism to self‐limit HBV replication, wherein the upregulation of lncRNA HOXA‐AS2, induced by HBV DNA pol, can epigenetically suppress cccDNA transcription.
The study found that HBV DNA pol upregulates the expression of host lncRNA HOXA‐AS2 after establishing persistent high‐level HBV replication. Subsequently, HOXA‐AS2 directly binds to HBV cccDNA and recruits MTA1‐HDAC1/2 deacetylase complexes, epigenetically suppressing HBV transcription. These findings provide new insights into the epigenetic inhibition of cccDNA transcription by lncRNAs and elucidate a mechanism for self‐limiting HBV replication.
In this paper, a calibration method for non-isotropic point light source is developed, which is capable of calibrating position and orientation of the point light source with a single image ...synchronously. Based on the bidirectional reflectance distribution function (BRDF), the relationship between the shape of observed surface and the recorded grayscale image is firstly investigated in a more accurate way. Based on this model, a cost function is proposed to evaluate the estimation error, and a new cumulative, error-free iteration method is designed to recursively estimate the point light source parameters. The average simulation rebuilding root mean square error (RMSE) is below 0.9. The experiments are performed by calibrating a point light source in a photometric stereo measurement system, and the corresponding RMSE is below 1.2 in the unit of grayscale. Further analysis shows one image is enough to achieve the precision calibration using our proposed method.
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