306 research outputs found
An Efficient Multilevel Fast Multipole Algorithm to Solve Volume Integral Equation for Arbitrary Inhomogeneous Bi-Anisotropic Objects
A volume integral equation (VIE) based on the mixed-potential representation is presented to analyze the electromagnetic scattering from objects involving inhomogeneous bi-anisotropic materials. By discretizing the objects using tetrahedrons on which the commonly used Schaubert-Wilton-Glisson (SWG) basis functions are defined, the matrix equation is derived using the method of moments (MoM) combined with the Galerkin’s testing. Further, adopting an integral strategy of tetrahedron-to-tetrahedron scheme, the multilevel fast multipole algorithm (MLFMA) is proposed to accelerate the iterative solution, which is further improved by using the spherical harmonics expansion with a faster implementation and low memory requirement. The memory requirement of the radiation patterns of basis functions in the proposed MLFMA is several times less than that in the conventional MLFMA
An efficient background modeling approach based on vehicle detection
The existing Gaussian Mixture Model(GMM) which is widely used in vehicle detection suffers inefficiency in detecting foreground image during the model phase, because it needs quite a long time to blend the shadows in the background. In order to overcome this problem, an improved method is proposed in this paper. First of all, each frame is divided into several areas(A, B, C and D), Where area A, B, C and D are decided by the frequency and the scale of the vehicle access. For each area, different new learning rate including weight, mean and variance is applied to accelerate the elimination of shadows. At the same time, the measure of adaptive change for Gaussian distribution is taken to decrease the total number of distributions and save memory space effectively. With this method, different threshold value and different number of Gaussian distribution are adopted for different areas. The results show that the speed of learning and the accuracy of the model using our proposed algorithm surpass the traditional GMM. Probably to the 50th frame, interference with the vehicle has been eliminated basically, and the model number only 35% to 43% of the standard, the processing speed for every frame approximately has a 20% increase than the standard. The proposed algorithm has good performance in terms of elimination of shadow and processing speed for vehicle detection, it can promote the development of intelligent transportation, which is very meaningful to the other Background modeling methods. (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
iTRAQ-Based Comparative Proteomic Analysis Reveals Molecular Mechanisms Underlying Wing Dimorphism of the Pea Aphid, Acyrthosiphon pisum
Wing dimorphism is a widespread phenomenon in insects with an associated trade-off between flight capability and fecundity. Despite the molecular underpinnings of phenotypic plasticity that has already been elucidated, it is still not fully understood. In this study, we focused on the differential proteomics profiles between alate and apterous morphs of the pea aphid, Acyrthosiphon pisum at the fourth instar nymph and adult stages, using isobaric tags for relative and absolute quantitation (iTRAQ) in a proteomic-based approach. A total of 5,116 protein groups were identified and quantified in the three biological replicates, of which 836 were differentially expressed between alate and apterous morphs. A bioinformatics analysis of differentially expressed protein groups (DEPGs) was performed based on gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). KEGG enrichment analysis showed that DEPGs mainly participated in energy metabolism, amino acid biosynthesis and metabolism, and signal sensing and transduction. To verify the reliability of proteomics data, the transcriptional expression of 29 candidates of differentially expressed proteins were analyzed by quantitative real-time PCR (qRT-PCR), showing that 26 genes were consistent with those at proteomic levels. In addition, differentially expressed proteins between winged and wingless morphs that were linked to olfactory sense were investigated. Quantitative real-time PCR revealed the tissue- and morph-biased expression profiles. These results suggested that olfactory sense plays a key role in wing dimorphism of aphids. The comparative proteomic analysis between alate and apterous morphs of the pea aphid provides a novel insight into wing development and dimorphism in aphids and will help facilitate our understanding of these concepts at molecular levels
Mapping the time-varying functional brain networks in response to naturalistic movie stimuli
One of human brain’s remarkable traits lies in its capacity to dynamically coordinate the activities of multiple brain regions or networks, adapting to an externally changing environment. Studying the dynamic functional brain networks (DFNs) and their role in perception, assessment, and action can significantly advance our comprehension of how the brain responds to patterns of sensory input. Movies provide a valuable tool for studying DFNs, as they offer a naturalistic paradigm that can evoke complex cognitive and emotional experiences through rich multimodal and dynamic stimuli. However, most previous research on DFNs have predominantly concentrated on the resting-state paradigm, investigating the topological structure of temporal dynamic brain networks generated via chosen templates. The dynamic spatial configurations of the functional networks elicited by naturalistic stimuli demand further exploration. In this study, we employed an unsupervised dictionary learning and sparse coding method combing with a sliding window strategy to map and quantify the dynamic spatial patterns of functional brain networks (FBNs) present in naturalistic functional magnetic resonance imaging (NfMRI) data, and further evaluated whether the temporal dynamics of distinct FBNs are aligned to the sensory, cognitive, and affective processes involved in the subjective perception of the movie. The results revealed that movie viewing can evoke complex FBNs, and these FBNs were time-varying with the movie storylines and were correlated with the movie annotations and the subjective ratings of viewing experience. The reliability of DFNs was also validated by assessing the Intra-class coefficient (ICC) among two scanning sessions under the same naturalistic paradigm with a three-month interval. Our findings offer novel insight into comprehending the dynamic properties of FBNs in response to naturalistic stimuli, which could potentially deepen our understanding of the neural mechanisms underlying the brain’s dynamic changes during the processing of visual and auditory stimuli
A Dopa Decarboxylase Modulating the Immune Response of Scallop Chlamys farreri
BACKGROUND: Dopa decarboxylase (DDC) is a pyridoxal 5-phosphate (PLP)-dependent enzyme that catalyzes the decarboxylation of L-Dopa to dopamine, and involved in complex neuroendocrine-immune regulatory network. The function for DDC in the immunomodulation remains unclear in invertebrate. METHODOLOGY: The full-length cDNA encoding DDC (designated CfDDC) was cloned from mollusc scallop Chlamys farreri. It contained an open reading frame encoding a polypeptide of 560 amino acids. The CfDDC mRNA transcripts could be detected in all the tested tissues, including the immune tissues haemocytes and hepatopancreas. After scallops were treated with LPS stimulation, the mRNA expression level of CfDDC in haemocytes increased significantly (5.5-fold, P<0.05) at 3 h and reached the peak at 12 h (9.8-fold, P<0.05), and then recovered to the baseline level. The recombinant protein of CfDDC (rCfDDC) was expressed in Escherichia coli BL21 (DE3)-Transetta, and 1 mg rCfDDC could catalyze the production of 1.651±0.22 ng dopamine within 1 h in vitro. When the haemocytes were incubated with rCfDDC-coated agarose beads, the haemocyte encapsulation to the beads was increased significantly from 70% at 6 h to 93% at 24 h in vitro in comparison with that in the control (23% at 6 h to 25% at 24 h), and the increased haemocyte encapsulation was repressed by the addition of rCfDDC antibody (which is acquired via immunization 6-week old rats with rCfDDC). After the injection of DDC inhibitor methyldopa, the ROS level in haemocytes of scallops was decreased significantly to 0.41-fold (P<0.05) of blank group at 12 h and 0.47-fold (P<0.05) at 24 h, respectively. CONCLUSIONS: These results collectively suggested that CfDDC, as a homologue of DDC in scallop, modulated the immune responses such as haemocytes encapsulation as well as the ROS level through its catalytic activity, functioning as an indispensable immunomodulating enzyme in the neuroendocrine-immune regulatory network of mollusc
Cell surface receptor kinase FERONIA linked to nutrient sensor TORC1 signaling controls root hair growth at low temperature in Arabidopsis thaliana
Root hairs (RH) are excellent model systems for studying cell size regulation since they elongate several hundred-fold their original size. Their growth is determined both by intrinsic and environmental signals. Although nutrients availability in the soil are key factors for a sustained plant growth, the molecular mechanisms underlying their perception and downstream signaling pathways remains unclear. Here, we identified that a low temperature triggers a strong RH cell elongation response involving the cell surface receptor kinase FERONIA (FER) and nutrient sensor TORC1 pathway. We found that FER is required to perceive limited nutrients availability caused by low temperature, to interacts with and activate TORC1-downstream components to trigger RH growth. Nitrates perceived and transported by NRT1.1 were found to mimic this growth response at low temperature. Our findings reveal a new molecular mechanism by which a central hub composed by FER-TORC1 controls RH cell elongation under low temperature.Fil: Martinez Pacheco, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Song, Limei. Hunan University; ChinaFil: Berdion Gabarain, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Peralta, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Urzúa Lehuedé, Tomás. Universidad Andrés Bello; ChileFil: Ibeas, Miguel Ángel. Universidad Andrés Bello; ChileFil: Zhu, Sirui. Hunan University; ChinaFil: Shen, Yanan. Hunan University; ChinaFil: Yu, Feng. Hunan University; ChinaFil: Estevez, Jose Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad Andrés Bello; Chil
Potential molecular mechanisms of Erlongjiaonang action in idiopathic sudden hearing loss: A network pharmacology and molecular docking analyses
BackgroundIdiopathic sudden hearing loss (ISHL) is characterized by sudden unexplainable and unilateral hearing loss as a clinically emergent symptom. The use of the herb Erlongjiaonang (ELJN) in traditional Chinese medicine is known to effectively control and cure ISHL. This study explored the underlying molecular mechanisms using network pharmacology and molecular docking analyses.MethodThe Traditional Chinese Medicine System Pharmacological database and the Swiss Target Prediction database were searched for the identification of ELJN constituents and potential gene targets, respectively, while ISHL-related gene abnormality was assessed using the Online Mendelian Inheritance in Man and Gene Card databases. The interaction of ELJN gene targets with ISHL genes was obtained after these databases were cross-screened, and a drug component–intersecting target network was constructed, and the gene ontology (GO) terms, Kyoto Encyclopedia of Genes and Genomes, and protein–protein interaction networks were analyzed. Cytoscape software tools were used to map the active components–crossover target–signaling pathway network and screened targets were then validated by establishing molecular docking with the corresponding components.ResultErlongjiaonang contains 85 components and 250 corresponding gene targets, while ISHL has 714 disease-related targets, resulting in 66 cross-targets. The bioinformatical analyses revealed these 66 cross-targets, including isorhamnetin and formononetin on NOS3 expression, baicalein on AKT1 activity, and kaempferol and quercetin on NOS3 and AKT1 activity, as potential ELJN-induced anti-ISHL targets.ConclusionThis study uncovered potential ELJN gene targets and molecular signaling pathways in the control of ISHL, providing a molecular basis for further investigation of the anti-ISHL activity of ELJN
The association between diabetes status and latent-TB IGRA levels from a cross-sectional study in eastern China
BackgroundThere is a debate regarding the sensitivity of the QuantiFERON-TB Gold In-Tube (QFT) among people with diabetes, and prior studies have shown heterogeneous results. We evaluated whether the QFT TB antigen was modified among persons with differing diabetes status and other related risk factors.MethodsA cross-sectional study of 5,302 people was conducted to screen latent tuberculosis infection (LTBI) in eastern China. The QFT assay was performed as an indicator of LTBI. Fasting plasma glucose (FPG) was collected from each participant; the definition of diabetes followed the guidelines from the American Diabetes Association. Participants were classified into normoglycemia, prediabetes, undiagnosed diabetes, and previously diagnosed diabetes to evaluate the relationship between the QFT TB antigen and distinct diabetes status.ResultsTB antigen values from the QFT were statistically different among participants with differing diabetes status (P = 0.008). Persons with undiagnosed diabetes had a higher TB antigen value (0.96 ± 0.20) than persons with normoglycemia (0.50 ± 0.02, P < 0.05). However, the TB antigen values demonstrated no significant difference among the four different diabetic groups when stratified by the standard cutoff for the QFT (P = 0.492 for the positive group and P = 0.368 for the negative group). In a linear regression model, we found that FPG, age, and smoking were positively associated with the QFT TB antigen value (P = 0.017, P < 0.001, and P < 0.001).ConclusionsDiabetes status had little influence on the level of QFT TB antigen response among IGRA-positive persons. However, FPG, old age, and smoking were important risk factors for increasing levels of QFT TB antigen
Lewis (y) Antigen Overexpression Increases the Expression of MMP-2 and MMP-9 and Invasion of Human Ovarian Cancer Cells
Lewis (y) antigen is a difucosylated oligosaccharide present on the plasma membrane, and its overexpression is frequently found in human cancers and has been shown to be associated with poor prognosis. Our previous studies have shown that Lewis (y) antigen plays a positive role in the process of invasion and metastasis of ovarian cancer cells. However, the mechanisms by which Lewis (y) antigen enhances the invasion and tumor metastasis are still unknown. In this study, we established a stable cell line constitutively expressing Lewis (y) antigen (RMG-1-hFUT) by transfecting the cDNA encoding part of the human α1,2-fucosyltransferase (α1,2-FUT) gene into the ovarian cancer cell line RMG-1, and investigated whether Lewis (y) antigen regulates the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9, and tissue inhibitors of metalloproteinases (TIMP-1) and TIMP-2. We found that RMG-1-hFUT cells exhibited higher invasive capacities than their control cells. In addition, expression of TIMP-1 and TIMP-2 was down-regulated and expression of MMP-2 and MMP-9 was up-regulated. Anti-Lewis (y) antigen antibody treatment significantly reversed the expression of TIMP-1, TIMP-2, MMP-2 and MMP-9. Taken together, we provide the first evidence that down-regulation of TIMP-1 and TIMP-2 and up-regulation of MMP-2 and MMP-9 represents one of the mechanisms by which Lewis (y) antigen promotes cell invasion
A universal optical modulator for synthetic topologically tuneable structured matter
Topologically structured matter, such as metasurfaces and metamaterials, have
given rise to impressive photonic functionality, fuelling diverse applications
from microscopy and holography to encryption and communication. Presently these
solutions are limited by their largely static nature and preset functionality,
hindering applications that demand dynamic photonic systems with reconfigurable
topologies. Here we demonstrate a universal optical modulator that implements
topologically tuneable structured matter as virtual pixels derived from
cascading low functionality tuneable devices, altering the paradigm of phase
and amplitude control to encompass arbitrary spatially varying retarders in a
synthetic structured matter device. Our approach opens unprecedented
functionality that is user-defined with high flexibility, allowing our
synthetic structured matter to act as an information carrier, beam generator,
analyser, and corrector, opening an exciting path to tuneable topologies of
light and matter
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