With the rapid development of wireless communications, vehicular ad hoc networks (VANETs) have recently attracted great attention. Although IEEE 802.11p has been approved as the standard medium ...access control (MAC) protocol for vehicle-to-vehicle communications, its contention-based nature and inability to handle hidden-terminal problems may incur high packet collision probability under high-traffic-density situations. To overcome the shortcoming of IEEE 802.11p, time-division multiple-access (TDMA)-based protocols are proposed. However, packet collisions can still occur due to contention or multiple vehicles using the same slot while approaching each other, i.e., encounter collisions, particularly in two-way traffic roads. Some proposed remedying the encounter collisions for two-way traffic by partitioning a frame into two sets: one for the traffic in each direction. However, these proposed protocols are harder to adapt to the uneven traffic loads on both directions and cannot solve the problem of four-way intersections. In this paper, we propose a new TDMA protocol called prediction-based TDMA MAC (PTMAC) based on a novel way of predicting encounter collisions and effectively reducing the number of collisions. To the best of our knowledge, PTMAC is the first protocol that is designed for both two-way traffic and four-way intersections. It has shown that, based on this predictability, the encounter collisions can be greatly reduced in both two-way traffic and four-way intersections, regardless of the traffic loads on different road segments.
In this paper, a novel D-shaped photonic crystal fiber sensor for simultaneous measurements of magnetic field and temperature is proposed and characterized. Based on the surface plasmon resonance ...theory, the D-shaped flat surface coated with a gold layer is in direct contact with magnetic fluid to detect magnetic field, and one of the relatively small air holes near the fiber core is filled with polydimethylsiloxane (PDMS) to sense temperature. The realization of measuring the magnetic field and temperature separately through two channels depends on the fact that the magnetic field only changes the refractive index of the magnetic fluid, but has no effect on the refractive index of PDMS. The refractive index of the magnetic fluid and PDMS can be affected by temperature at the same time. The sensor designed in this work can separate the variations of the magnetic field and temperature simultaneously, therefore solving the cross-sensitivity problem to further improve the magnetic field sensitivity. When the thickness of the gold film is 50 nm and the radius of the filling hole is 0.52 µm, the magnetic field sensitivity and the temperature sensitivity of magnetic field sensor based on temperature self-reference can reach 0.14274 nm/Oe and −0.229 nm/°C, respectively.
In order to solve the problem of unknown target birth intensity in multi-target tracking, an improved GM-PHD filtering algorithm based on virtual track is proposed. According to the measurement set ...in the monitoring area, the virtual tracks of the birth targets are established by using the motion model of the targets. The false tracks modeled by the clutter are eliminated by PHD filter, and the states of the birth targets are extracted. The simulation results show that the algorithm performs well in dense clutter environment.
Acetylation plays an important role in regulating the chaperone activity of heat shock protein 90 (Hsp90) during malignant transformation through the stabilization and conformational maturation of ...oncogenic proteins. However, the functional acetylation sites, potential anticancer drug targets, are still emerging. We found that acetylation at K292 in Hsp90α is critical for the development and treatment of breast cancer. Acetylation at K292 not only augments the affinity of Hsp90 to ATP, cochaperones, and client proteins but it also promotes cancer cell colony formation, migration, and invasion in vitro as well as tumor growth in vivo. Importantly, K292‐acetylated Hsp90 has been validated as an exciting anticancer drug target by interfering with the complex formation between K292‐acetylated Hsp90 and cochaperone Cdc37, leading to diminishment of kinase client maturation and proteasome‐dependent degradation of kinase substrates. Furthermore, we showed that simvastatin prevented, whereas LBH589 promoted, the progression of Hsp90 chaperone cycling and client maturation, resulting in an increment of cell apoptosis by the combination of simvastatin and LBH589 in a mouse xenograft model. These data suggest that simvastatin is a novel Hsp90 inhibitor to disrupt the formation of the K292‐acetylated Hsp90/Cdc37 complex in triple‐negative breast cancer cells. The combination of simvastatin with LBH589 could be used as a novel therapeutic strategy for triple‐negative breast cancer.
Acetylation status of heat shock protein 90 (Hsp90) on K292 is positively associated with cancer progression. K292‐acetylated Hsp90 promotes growth, invasion, and tumorigenicity of MDA‐MB‐231 cells. Simvastatin abrogates the complex formation of Hsp90 and Cdc37 against triple‐negative breast cancer by targeting K292‐acetylated Hsp90.
Perovskite based photodetectors and hybrid devices possess distinctive properties which have enabled considerable practical applications since perovskite is an ideal candidate for higher sensitivity ...and response speed. In this work, an elegant approach of fabricating hybrid photodetectors based on perovskite-metallic nanostructures is shown. By combining gold triangle nanoantennae with a CH3NH2PbI3 film, a simple yet effective fabrication method of hybrid organic-inorganic perovskite photodetectors with improved performanceis experimentally demonstrated. Finite difference time domain calculations agree well with experimental results. Perovskite-assisted devices are highly attractive due to their unique properties and the results shown in this work may find extensive potential applications for novel flexible photodetectors and other related optical devices.
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•A hybrid photodetecting system is experimentally demonstrated and characterized.•This device exhibits higher photocurrent due to enhanced electric field of plasmonic arrays.•The measured external quantum efficiency is 12.6% at 450 nm wavelength.
Lactobacillus helveticus LB 10 proteinases immobilized with sodium alginate were used to hydrolyze whey protein to produce angiotensin-I-converting enzyme (ACE)-inhibitory peptides. The generated ...hydrolysates were tested for ACE-inhibitory activity and for their ability to be transported across Caco-2 cell monolayers. Using a response surface method, we determined that a proteinase concentration of 7.55 mg/mL, sodium alginate concentration of 2.03 g/100 mL, and glutaraldehyde concentration of 0.39% were found to be the optimal immobilization conditions. Compared with free proteinase, the immobilized proteinase had significantly higher pH, thermal and storage stability, and reusability. Whey protein hydrolysates were fractionated by gel filtration chromatography and ACE-inhibitory peptide mixtures were transported across Caco-2 cell monolayers in a human intestinal-absorption model. The di- and tripeptides KA, EN, DIS, EVD, LF, AIV, and VFK (half-maximal inhibitory concentrations (mean ± standard deviation) of 1.24 ± 0.01, 1.43 ± 0.04, 1.59 ± 0.27, 1.32 ± 0.05, 1.60 ± 0.39, 2.66 ± 0.02, and 1.76 ± 0.09 mmol/L, respectively) were detected on the basolateral side of the Caco-2 cell monolayer using ultra-performance liquid chromatography-tandem mass spectrometry. These results highlight that ACE-inhibitory peptides are present on the basolateral side of the Caco-2 cell model after transportation of whey protein hydrolysate across the Caco-2 cell membrane.
In recent years, the development of metamaterials and metasurfaces has drawn great attention, enabling many important practical applications. Focusing and lensing components are of extreme importance ...because of their significant potential practical applications in biological imaging, display, and nanolithography fabrication. Metafocusing devices using ultrathin structures (also known as metasurfaces) with superlensing performance are key building blocks for developing integrated optical components with ultrasmall dimensions. In this article, we review the metamaterial superlensing devices working in transmission mode from the perfect lens to two-dimensional metasurfaces and present their working principles. Then we summarize important practical applications of metasurfaces, such as plasmonic lithography, holography, and imaging. Different typical designs and their focusing performance are also discussed in detail.
Introduction:
Fruit diseases have a serious impact on fruit production, causing a significant drop in economic returns from agricultural products. Due to its excellent performance, deep learning is ...widely used for disease identification and severity diagnosis of crops. This paper focuses on leveraging the high-latitude feature extraction capability of deep convolutional neural networks to improve classification performance.
Methods:
The proposed neural network is formed by combining the Inception module with the current state-of-the-art EfficientNetV2 for better multi-scale feature extraction and disease identification of citrus fruits. The VGG is used to replace the U-Net backbone to enhance the segmentation performance of the network.
Results:
Compared to existing networks, the proposed method achieved recognition accuracy of over 95%. In addition, the accuracies of the segmentation models were compared. VGG-U-Net, a network generated by replacing the backbone of U-Net with VGG, is found to have the best segmentation performance with an accuracy of 87.66%. This method is most suitable for diagnosing the severity level of citrus fruit diseases. In the meantime, transfer learning is applied to improve the training cycle of the network model, both in the detection and severity diagnosis phases of the disease.
Discussion:
The results of the comparison experiments reveal that the proposed method is effective in identifying and diagnosing the severity of citrus fruit diseases identification.
Metasurfaces exhibit excellent performance in the regulation of optical field parameters, such as phase, amplitude, and polarization, by using nanounit structures. The characteristics of metasurface ...miniaturization and its combination with advanced semiconductor processes have attracted significant attention, and their design and applications have become the focus of researchers recently. The design of traditional metasurfaces often requires professional designers. Consequently, design work has become difficult and time-consuming with the increase in the complexity of metasurface design. The introduction of artificial intelligence (AI) in metasurface design work has resulted in its rapid development and simplification. Furthermore, metasurfaces have begun to play the role of hidden layers in optical neural networks, and their intelligent properties are gradually being identified. Based on the introduction of the metasurface control mechanism, this paper reviews its intelligent designs and progress. Additionally, the feasibility, necessity, and broad prospects of the combination of AI with metasurfaces are clarified.
With rapid urbanization accompanied by lifestyle changes, children and adolescents living in metropolitan areas are faced with many time use choices that compete with sleep. This study reports on the ...sleep hygiene of urban Chinese school students, and investigates the relationship between habitual after-school activities and sleep duration, schedule and quality on a regular school day.
Cross-sectional, school-based survey of school children (Grades 4-8) living in Shanghai, China, conducted in 2011. Self-reported data were collected on students' sleep duration and timing, sleep quality, habitual after-school activities (i.e. homework, leisure-time physical activity, recreational screen time and school commuting time), and potential correlates.
Mean sleep duration of this sample (mean age: 11.5-years; 48.6% girls) was 9 hours. Nearly 30% of students reported daytime tiredness. On school nights, girls slept less (p<0.001) and went to bed later (p<0.001), a sex difference that was more pronounced in older students. Age by sex interactions were observed for both sleep duration (p=0.005) and bedtime (p=0.002). Prolonged time spent on homework and mobile phone playing was related to shorter sleep duration and later bedtime. Adjusting for all other factors, with each additional hour of mobile phone playing, the odds of daytime tiredness and having difficulty maintaining sleep increased by 30% and 27% among secondary students, respectively.
There are sex differences in sleep duration, schedule and quality. Habitual activities had small but significant associations with sleep hygiene outcomes especially among secondary school students. Intervention strategies such as limiting children's use of electronic screen devices after school are implicated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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