The application of improved signal summing method into the spacecraft force limited vibration test

This paper provides an improved signal summing method for the spacecraft force limited vibration test system with eight force transducers. The key point for this method is to change the combination way of the signals coming out of the eight force transducers while the formulas inside the signal conditioning amplifier have been used skillfully. This method had been successfully adopted in the spacecraft force limited vibration test and the accuracy requirements of key force and moment signals have been met. And this method has been proved to be a very powerful tool for providing the critical force and moment data used to determine the force limited profile during the spacecraft dynamic test

Influence of hyperuricemia on the reproductive function of female rats and its mechanism

Objective To investigate the influence of hyperuricemia (HUA) on the reproductive function of female rats and its mechanism. Methods A total of 18 female Wistar rats were randomly divided into HUA group, HUA recovery group (HR group), and control group (N group), with 6 rats in each group. The rats in the HUA group and the HR group were given intragastric administration of 50 mg/kg uric acid and intraperitoneal injection of 250 mg/kg oteracil potassium every day, and since week 9, the rats in the HR group were given an equal volume of normal saline by gavage and intraperitoneal injection, while the treatment remained unchanged for those in the HUA group, for another 7 weeks; the rats in the N group were given an equal vo-lume of normal saline by gavage and intraperitoneal injection for 16 weeks. At week 16, body weight, uterine mass, and ovarian mass were measured for all three groups, and uterine and ovarian coefficients were calculated; hematoxylin-eosin staining was used to observe the pathological changes of the uterus and ovarian tissue; enzyme-linked immunosorbent assay was used to measure the serum levels of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2); the vaginal exfoliation cell smear method was used to observe the estrous cycle of rats; colorimetry was used to measure the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) in uterine tissue of the three groups; immunofluorescence assay was used to measure the fluorescence intensity of tumor necrosis factor-α (TNF-α) in uterine tissue of the three groups. Results Compared with the N group, the HUA group had significant reductions in uterine coefficient, number of follicles, endometrial thickness, and estrous interval, a significant increase in the serum level of FSH, significant reductions in the levels of SOD and GSH in uterine tissue, and a significant increase in the content of MDA (F=7.80-111.40,t=3.95-12.37,P<0.05), as well as an increase in the fluorescence intensity of TNF-α in uterine tissue. Compared with the HUA group, the HR group had significant increases in the number of follicles, endometrial thickness, the serum level of FSH, and the levels of SOD and GSH in uterine tissue and a significant reduction in the level of MDA (t=3.40-11.56,P<0.05), as well as a reduction in the fluorescence intensity of TNF-α in uterine tissue. Conclusion HUA can cause the decline of reproductive function in female rats, which may be associated with the increase in the serum level of uric acid, the disorder of sex hormone secretion, the increase in the level of oxidative stress, and the induction of inflammatory response

Cooperation-based sperm clusters mediate sperm oviduct entry and fertilization

Sperm cooperation has been observed in multiple species, yet its existence and benefit for reproductive success in mammals remains underexplored. Here, combining tissue-clearing with deep three-dimensional imaging, we demonstrate that postcopulatory mouse sperm congregate into unidirectional sperm cooperative clusters at the utero-tubal junction (UTJ), a key physical barrier for passage into the oviduct. Reducing sperm number in male mice by unilateral vasoligation or busulfan-treatment impairs sperm cluster formation and oviduct entry. Interestingly, sperm derived from Tex101-/- mouse has normal number, motility and morphology, yet they cannot form sperm cluster and fail to pass through the UTJ, which is at least in part due to the altered tail beating pattern of the Tex101-/- sperm. Moreover, Tex101-/- sperm's defect in oviduct entry cannot be rescued by the presence of wild-type (WT) sperm in the same uteri by sequential mating, suggesting sperm cooperative cluster as an essential behavior contributing to male fertility, which could be related to human infertility or subfertility

PANDORA-seq expands the repertoire of regulatory small RNAs by overcoming RNA modifications

Although high-throughput RNA sequencing (RNA-seq) has greatly advanced small non-coding RNA (sncRNA) discovery, the currently widely used complementary DNA library construction protocol generates biased sequencing results. This is partially due to RNA modifications that interfere with adapter ligation and reverse transcription processes, which prevent the detection of sncRNAs bearing these modifications. Here, we present PANDORA-seq (panoramic RNA display by overcoming RNA modification aborted sequencing), employing a combinatorial enzymatic treatment to remove key RNA modifications that block adapter ligation and reverse transcription. PANDORA-seq identified abundant modified sncRNAs—mostly transfer RNA-derived small RNAs (tsRNAs) and ribosomal RNA-derived small RNAs (rsRNAs)—that were previously undetected, exhibiting tissue-specific expression across mouse brain, liver, spleen and sperm, as well as cell-specific expression across embryonic stem cells (ESCs) and HeLa cells. Using PANDORA-seq, we revealed unprecedented landscapes of microRNA, tsRNA and rsRNA dynamics during the generation of induced pluripotent stem cells. Importantly, tsRNAs and rsRNAs that are downregulated during somatic cell reprogramming impact cellular translation in ESCs, suggesting a role in lineage differentiation

Moving Object Detection Based on Fusion of Depth Information and RGB Features

The detection of moving objects is one of the key problems in the field of computer vision. It is very important to detect moving objects accurately and rapidly for automatic driving. In this paper, we propose an improved moving object detection method to overcome the disadvantages of the RGB information-only-based method in detecting moving objects that are susceptible to shadow interference and illumination changes by adding depth information. Firstly, a convolutional neural network (CNN) based on the color edge-guided super-resolution reconstruction of depth maps is proposed to perform super-resolution reconstruction of low-resolution depth images obtained by depth cameras. Secondly, the RGB-D moving object detection algorithm is based on fusing the depth information of the same scene with RGB features for detection. Finally, in order to evaluate the effectiveness of the algorithm proposed in this paper, the Middlebury 2005 dataset and the SBM-RGBD dataset are successively used for testing. The experimental results show that our super-resolution reconstruction algorithm achieves the best results among the six commonly used algorithms, and our moving object detection algorithm improves the detection accuracy by up to 18.2%, 9.87% and 40.2% in three scenes, respectively, compared with the original algorithm, and it achieves the best results compared with the other three recent RGB-D-based methods. The algorithm proposed in this paper can better overcome the interference caused by shadow or illumination changes and detect moving objects more accurately

Effect of superhydrophobicity on surface damage of silicone rubber under AC voltage

In this paper, the influence of superhydrophobicity on the surface damage of silicone rubber is studied. On a common silicone rubber surface, a droplet can become elongated, and arc discharge induced by the droplet can cause tracking on the silicone rubber surface. However, for a superhydrophobic silicone rubber surface, a droplet can leave the silicone rubber due to the low adhesion of the superhydrophobic surface. Accordingly, arc discharge caused by the droplet does not occur, and the surface of the silicone rubber is not affected. Results demonstrate that using a superhydrophobic surface has a significant effect on limiting the surface damage of silicone rubber

Effect of superhydrophobicity on flashover characteristics of silicone rubber under wet conditions

Superhydrophobic surface has aroused much interest among researchers due to the low adhesion between water and a substrate surface. This study focuses on the influence of the low adhesion of superhydrophobic surface on flashover characteristics under wet conditions. The flashover experiments were conducted under two different wet conditions. One was placing a constant volume droplet on the silicone rubber. The other one was that silicone rubber was wetted by salt fog. It was found that the adhesion between water droplets and a superhydrophobic surface was very low because of the presence of air cushion. Accordingly, water droplets were easy to slide on a superhydrophobic surface under the effect of electric filed. The sliding of droplets could provide a longer insulation path before flashover occurred. Results showed that flashover voltage could be improved greatly on a superhydrophobic silicone rubber surface

P2IT: Predicting packet interarrival time in asynchronous duty-cycling sensor networks

In this paper, we investigate the predictability of packet arrivals in asynchronous duty-cycling wireless sensor networks (WSNs). We conduct statistical analysis on data traces collected in both outdoor large-scale and indoor testbed WSN to show that traditional well-known traffic models, e.g., Poisson process and Self-similarity process, do not fit well for modeling packet arrivals in both networks. According to our observations, some key characteristics such as sleeping interval and sampling rate have significant impact on the traffic patterns under Low power listening (LPL) models. Hence, we raise a question: could we achieve accurate prediction on the packet arrivals in asynchronous duty-cycling WSNs? To answer this question, we design a novel data-driven predictor P2IT focusing on two prediction goals: (i) the arrival time of the next packet (ii) the number of arrival packets within a short time interval. We conduct extensive trace-driven experiments to demonstrate that our predictor achieves high acuracies on both prediction goals under various experimental settings. © 2013 IEEE