132 research outputs found
Shape-Aware Fine-Grained Classification of Erythroid Cells
Fine-grained classification and counting of bone marrow erythroid cells are
vital for evaluating the health status and formulating therapeutic schedules
for leukemia or hematopathy. Due to the subtle visual differences between
different types of erythroid cells, it is challenging to apply existing
image-based deep learning models for fine-grained erythroid cell
classification. Moreover, there is no large open-source datasets on erythroid
cells to support the model training. In this paper, we introduce BMEC (Bone
Morrow Erythroid Cells), the first large fine-grained image dataset of
erythroid cells, to facilitate more deep learning research on erythroid cells.
BMEC contains 5,666 images of individual erythroid cells, each of which is
extracted from the bone marrow erythroid cell smears and professionally
annotated to one of the four types of erythroid cells. To distinguish the
erythroid cells, one key indicator is the cell shape which is closely related
to the cell growth and maturation. Therefore, we design a novel shape-aware
image classification network for fine-grained erythroid cell classification.
The shape feature is extracted from the shape mask image and aggregated to the
raw image feature with a shape attention module. With the shape-attended image
feature, our network achieved superior classification performance (81.12\%
top-1 accuracy) on the BMEC dataset comparing to the baseline methods. Ablation
studies also demonstrate the effectiveness of incorporating the shape
information for the fine-grained cell classification. To further verify the
generalizability of our method, we tested our network on two additional public
white blood cells (WBC) datasets and the results show our shape-aware method
can generally outperform recent state-of-the-art works on classifying the WBC.
The code and BMEC dataset can be found on https://github.com/wangye8899/BMEC
Adaptive Model Prediction Control-Based Multi-Terrain Trajectory Tracking Framework for Mobile Spherical Robots
Owing to uncertainties in both kinematics and dynamics, the current
trajectory tracking framework for mobile robots like spherical robots cannot
function effectively on multiple terrains, especially uneven and unknown ones.
Since this is a prerequisite for robots to execute tasks in the wild, we
enhance our previous hierarchical trajectory tracking framework to handle this
issue. First, a modified adaptive RBF neural network (RBFNN) is proposed to
represent all uncertainties in kinodynamics. Then the Lyapunov function is
utilized to design its adaptive law, and a variable step-size algorithm is
employed in the weights update procedure to accelerate convergence and improve
stability. Hence, a new adaptive model prediction control-based instruction
planner (VAN-MPC) is proposed. Without modifying the bottom controllers, we
finally develop the multi-terrain trajectory tracking framework by employing
the new instruction planner VAN-MPC. The practical experiments demonstrate its
effectiveness and robustness.Comment: 10 pages, 20 figures. This work has been submitted to the IEEE
Transactions on Industrial Electronics for possible publicatio
Effect of polyphenol extract from Zanthoxylum bungeanum Maxim. on endocrine hormones and monoamine oxidase activity in a mouse model of climacteric depression
Purpose: To investigate the effects of polyphenol extract from Zanthoxylum bungeanum Maxim. (ZPPC) on endocrine hormones, monoamine oxidase activity and behavior in a mouse model of climacteric depression.Methods: Institute of Cancer Research (ICR) female albino mice (n = 50) weighing 24 – 26 g (mean wt = 25.0 ± 1.0 g) were randomly assigned to five groups of ten rats each: normal control group, negative control, and ZPPC (50 mg/kg), ZPPC (100 mg/kg) and ZPPC (200 mg/kg) groups. Depression was induced in the mice via oral administration of moclobemide at a dose of 20 mg/kg, and intraperitoneal injection of imipramine (20 mg/kg) 1 h and 30 min, before treatment. Tail suspension, forced swimming and voluntary activity tests were performed on the mice. The activity of monoamine oxidase (MAO) in mouse brain and the levels of endocrine hormones were also determined.Results: Treatment of depressed mice with ZPPC significantly and dose-dependently increased their tail suspension and immobility time (p < 0.05). The activity of monoamine oxidase in the brains of mice in the negative control group was significantly higher than that of normal control mice, but was significantly and dose-dependently reduced by ZPPC treatment (p < 0.05). Similarly, treatment of depressed mice with ZPPC significantly and dose-dependently reduced their serum adrenocorticotropin and corticosterone levels (p < 0.05).Conclusion: The results of this study indicate that ZPPC exerts antidepressant effect via suppression of brain MAO activity.
Keywords: Climacteric depression, Endocrine hormones, Menopause, Monoamine oxidase, Polyphenol
An MPC-based Optimal Motion Control Framework for Pendulum-driven Spherical Robots
Motion control is essential for all autonomous mobile robots, and even more
so for spherical robots. Due to the uniqueness of the spherical robot, its
motion control must not only ensure accurate tracking of the target commands,
but also minimize fluctuations in the robot's attitude and motors' current
while tracking. In this paper, model predictive control (MPC) is applied to the
control of spherical robots and an MPC-based motion control framework is
designed. There are two controllers in the framework, an optimal velocity
controller ESO-MPC which combines extend states observers (ESO) and MPC, and an
optimal orientation controller that uses multilayer perceptron (MLP) to
generate accurate trajectories and MPC with changing weights to achieve optimal
control. Finally, the performance of individual controllers and the whole
control framework are verified by physical experiments. The experimental
results show that the MPC-based motion control framework proposed in this work
is much better than PID in terms of rapidity and accuracy, and has great
advantages over sliding mode controller (SMC) for overshoot, attitude
stability, current stability and energy consumption.Comment: This paper has been submitted to Control Engineering Practic
In vitro analysis of phosphorothioate modification of DNA reveals substrate recognition by a multiprotein complex
A wide variety of prokaryotes possess DNA modifications consisting of sequence-specific phosphorothioates (PT) inserted by members of a five-gene cluster. Recent genome mapping studies revealed two unusual features of PT modifications: short consensus sequences and partial modification of a specific genomic site in a population of bacteria. To better understand the mechanism of target selection of PT modifications that underlies these features, we characterized the substrate recognition of the PT-modifying enzymes termed DptC, D and E in a cell extract system from Salmonella. The results revealed that double-stranded oligodeoxynucleotides underwent de novo PT modification in vitro, with the same modification pattern as in vivo, i. e., GpsAAC/GpsTTC motif. Unexpectedly, in these in vitro analyses we observed no significant effect on PT modification by sequences flanking GAAC/GTTC motif, while PT also occurred in the GAAC/GTTC motif that could not be modified in vivo. Hemi-PT DNA also served as substrate of the PT-modifying enzymes, but not single-stranded DNA. The PT-modifying enzymes were then found to function as a large protein complex, with all of three subunits in tetrameric conformations. This study provided the first demonstration of in vitro DNA PT modification by PT-modifying enzymes that function as a large protein complex.National Natural Science Foundation (China) (Grant 31470183)National Natural Science Foundation (China) (Grant 31400029)National Natural Science Foundation (China) (Grant 31170085)National Natural Science Foundation (China) (Grant 30570400)National Natural Science Foundation (China) (Grant 31070058)China. Ministry of Science and Technology (Grant 2012CB721004)China. Ministry of Science and Technology (Grant 2009ZX09501-008)Shanghai Municipal Council of Science and Technology (Shanghai Pujiang Program Grant 12PJD021)China Scholarship CouncilNational Science Foundation (U.S.) (Grant CHE-1019990)National Institute of Environmental Health Sciences (Grant ES002109)Singapore. National Research Foundation (Singapore-MIT Alliance for Research and Technology
Pathological phenotypes and in vivo DNA cleavage by unrestrained activity of a phosphorothioate-based restriction system in Salmonella
Prokaryotes protect their genomes from foreign DNA with a diversity of defence mechanisms, including a widespread restriction–modification (R–M) system involving phosphorothioate (PT) modification of the DNA backbone. Unlike classical R–M systems, highly partial PT modification of consensus motifs in bacterial genomes suggests an unusual mechanism of PT-dependent restriction. In Salmonella enterica, PT modification is mediated by four genes dptB–E, while restriction involves additional three genes dptF–H. Here, we performed a series of studies to characterize the PT-dependent restriction, and found that it presented several features distinct with traditional R–M systems. The presence of restriction genes in a PT-deficient mutant was not lethal, but instead resulted in several pathological phenotypes. Subsequent transcriptional profiling revealed the expression of > 600 genes was affected by restriction enzymes in cells lacking PT, including induction of bacteriophage, SOS response and DNA repair-related genes. These transcriptional responses are consistent with the observation that restriction enzymes caused extensive DNA cleavage in the absence of PT modifications in vivo. However, overexpression of restriction genes was lethal to the host in spite of the presence PT modifications. These results point to an unusual mechanism of PT-dependent DNA cleavage by restriction enzymes in the face of partial PT modification.National Natural Science Foundation (China) (Grant 31170085)National Natural Science Foundation (China) (Grant 31070058)Ministry of Science and Technology of the People's Republic of China (973 and 863 Programs)China Scholarship CouncilNational Science Foundation (U.S.) (Grant CHE-1019990)Shanghai Municipal Council of Science and Technology. Shanghai Pujiang Program (Grant 12PJD021
The correlation of the intestinal with pharyngeal microbiota in early neonates
IntroductionThe gut-lung axis has long been recognized as an important mechanism affecting intestinal and lung immunity. Still, few studies have examined the correlation between the intestinal and pharyngeal microbiota in early neonates, especially when feeding patterns are one of the main drivers of microbiota development.MethodsTo explore the composition and function of intestinal and pharyngeal microbiota and to analyze the effect of limited formula feeding on the initial microbiota colonization in early full-term neonates, we characterized the stool and oropharyngeal microbiota of 20 healthy full-term newborns sampled on days 0 and 5–7 after birth using 16S rRNA gene sequencing. Based on the sequencing results, a comparison was made of the compositions and functions of the intestinal and oropharyngeal microbiota for analysis.Results and discussionAt the phylum level, Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes were the most abundant in both niches. At the genus level, the species of pioneer bacteria were rich in the intestine and oropharynx but low in abundance on day 0. On days 5–7, Bifidobacterium (25.40%) and Escherichia-Shigella (22.16%) were dominant in the intestine, while Streptococcus (38.40%) and Staphylococcus (23.13%) were dominant in the oropharynx. There were eight core bacteria genera in the intestine and oropharynx on days 5–7, which were Bifidobacterium, Escherichia-Shigella, Staphylococcus, Streptococcus, Bacteroides, Parabacteroides, Rothia, and Acinetobacter. As indicated by PICRUSt analysis, on days 5–7, the intestinal microbiota was more predictive than the oropharyngeal microbiota in transcription, metabolism, cell motility, cellular processes and signaling, and organismal system function in the KEGG pathway. Compared to exclusive breastfeeding, limited formula feeding (40–60%) had no significant effect on the neonatal intestinal and oropharyngeal microbiota composition during the initial colonization period. Our results suggest that the initial colonization of microbiota is closely related to the ecological niche environment in the intestine and oropharynx, with their core microbiota being closely correlated. We found that early limited formula feeding could not significantly affect the initial colonization of microbiota in the intestine and oropharynx
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