480 research outputs found
Genetic characterization of \u3cem\u3eToxoplasma gondii\u3c/em\u3e from pigs from different localities in China by PCR-RFLP
Background
Toxoplasma gondii is a widely prevalent protozoan parasite that causes serious toxoplasmosis in humans and animals. The present study aimed to determine the genetic diversity of T. gondii isolates from pigs in Jiangxi, Sichuan, Guangdong Provinces and Chongqing Municipality in China using multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Methods
A total of 38 DNA samples were extracted from hilar lymph nodes of pigs with suspected toxoplasmosis, and were detected for the presence of T. gondii by semi-nested PCR of B1 gene. The positive DNA samples were typed at 11 genetic markers, including 10 nuclear loci, namely, SAG1, 5ā²-SAG2 and 3ā²-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast locus Apico. Results
Twenty-five of the 38 DNA samples were T. gondii B1 gene positive. Complete genotyping data for all loci could be obtained for 17 of the 25 samples. Two genotypes were revealed (ToxoDB PCR-RFLP genotypes #9 and #3). Sixteen samples belong to genotype #9 which is the major lineage in mainland China and one sample belongs to genotype #3 which is Type II variant. Conclusions
To our knowledge, this is the first report of genetic typing of T. gondii isolates from pigs in Jiangxi, Sichuan Province and Chongqing Municipality, and the first report of ToxoDB #3āT. gondii from pigs in China. These results have implications for the prevention and control of foodborne toxoplasmosis in humans
Coherent phonon Rabi oscillations with a high frequency carbon nanotube phonon cavity
Phonon-cavity electromechanics allows the manipulation of mechanical
oscillations similar to photon-cavity systems. Many advances on this subject
have been achieved in various materials. In addition, the coherent phonon
transfer (phonon Rabi oscillations) between the phonon cavity mode and another
oscillation mode has attracted many interest in nano-science. Here we
demonstrate coherent phonon transfer in a carbon nanotube phonon-cavity system
with two mechanical modes exhibiting strong dynamical coupling. The
gate-tunable phonon oscillation modes are manipulated and detected by extending
the red-detuned pump idea of photonic cavity electromechanics. The first- and
second-order coherent phonon transfers are observed with Rabi frequencies 591
kHz and 125 kHz, respectively. The frequency quality factor product
fQ_m~2=10^12 Hz achieved here is larger thank k_B T_base/h, which may enable
the future realization of Rabi oscillations in the quantum regime
Strongly-coupled nanotube electromechanical resonators
Coupling an electromechanical resonator with carbon-nanotube quantum dots is
a significant method to control both the electronic charge and the spin quantum
states. By exploiting a novel micro-transfer technique, we fabricate two
strongly-coupled and electrically-tunable mechanical resonators on a single
carbon nanotube for the first time. The frequency of the two resonators can be
individually tuned by the bottom gates, and strong coupling is observed between
the electron charge and phonon modes of each resonator. Furthermore, the
conductance of either resonator can be nonlocally modulated by the phonon modes
in the other resonator. Strong coupling is observed between the phonon modes of
the two resonators, which provides an effective long distance electron-electron
interaction. The generation of phonon-mediated-spin entanglement is also
theoretically analyzed for the two resonators. This strongly-coupled nanotube
electromechanical resonator array provides an experimental platform for future
studies of the coherent electron-phonon interaction, the phonon mediated
long-distance electron interaction, and entanglement state generation
Attention Mechanisms in Computer Vision: A Survey
Humans can naturally and effectively find salient regions in complex scenes.
Motivated by this observation, attention mechanisms were introduced into
computer vision with the aim of imitating this aspect of the human visual
system. Such an attention mechanism can be regarded as a dynamic weight
adjustment process based on features of the input image. Attention mechanisms
have achieved great success in many visual tasks, including image
classification, object detection, semantic segmentation, video understanding,
image generation, 3D vision, multi-modal tasks and self-supervised learning. In
this survey, we provide a comprehensive review of various attention mechanisms
in computer vision and categorize them according to approach, such as channel
attention, spatial attention, temporal attention and branch attention; a
related repository https://github.com/MenghaoGuo/Awesome-Vision-Attentions is
dedicated to collecting related work. We also suggest future directions for
attention mechanism research.Comment: 27 pages, 9 figure
Interleukin-22 ameliorates liver fibrosis through miR-200a/beta-catenin
IL-22 ameliorates liver fibrosis by inhibiting hepatic stellate cells (HSC), and loss of miR-200a is associated with the development of liver fibrosis. The study aimed to investigate the interplay between IL-22 and miR-200a in regulating liver fibrosis in vivo and in vitro. We observed that IL-22 significantly reduced the proliferation of HSC and increased the expression of p-STAT3. Ī²-catenin was identified as a target gene of miR-200a by luciferase reporter assay, and upregulation of miR-200a significantly attenuated the proliferation of HSC and reduced Ī²-catenin expression. IL-22 treatment increased expression of miR-200a and decreased expression of Ī²-catenin in HSC. The expression of p-STAT3 and miR-200a was elevated while Ī²-catenin was decreased in fibrotic rat liver after IL-22 treatment. Expression levels of Ī²-catenin and p-STAT3 were inversely correlated in fibrotic rat liver and HSC. Upregulation of Ī²-catenin suppressed expression of p-STAT3 in HSC. We concluded that IL-22 inhibits HSC activation and ameliorates liver fibrosis through enhancing expression of miR-200a and reducing expression of Ī²-catenin, suggesting there may be a crosstalk between IL-22/STAT3 and Ī²-catenin pathway
Accelerated Deficits of Spatial Learning and Memory Resulting From Prenatal Inflammatory Insult Are Correlated With Abnormal Phosphorylation and Methylation of Histone 3 in CD-1 Mice
Gestational infection causes various neurological deficits in offspring, such as age-related spatial learning and memory (SLM) decline. How inflammation causes age-related SLM dysfunction remains unknown. Previous research has indicated that histone modifications, such as phosphorylation of H3S10 (H3S10p) and trimethylation of H3K9 (H3K9me3) may be involved. In our study, pregnant mice received an intraperitoneal injection of lipopolysaccharide (LPS, 50 or 25 Ī¼g/kg) or normal saline during gestational days 15ā17. After normal parturition, the offspring were randomly separated into 1-, 6-, 12-, 18-, and 22-month-old groups. SLM performance was assessed using a radial six-arm water maze (RAWM). The hippocampal levels of H3S10p and H3K9me3 were detected using an immunohistochemical method. The results indicated that the offspring had significantly impaired SLM, with decreased H3S10p and increased H3K9me3 levels from 12 months onward. Maternal LPS exposure during late gestation significantly and dose-dependently exacerbated the age-related impairment of SLM, with the decrease in H3S10p and increase in H3K9me3 beginning at 12 months in the offspring. The histone modifications (H3S10p and H3K9me3) were significantly correlated with impairment of SLM. Our findings suggest that prenatal exposure to inflammation could exacerbate age-related impairments of SLM and changes in histone modifications in CD-1 mice from 12 months onward, and SLM impairment might be linked to decreased H3S10p and increased H3K9me3
Comparison of Chemical Compositions of the Pepper EOs From Different Cultivars and Their AChE Inhibitory Activity
Ā© The Author(s) 2020. Pepper is one of the most popular spices over the world and is called the King of Spices. Its essential oils (EOs) could alleviate neuronal ailments due to the inhibitory effect against acetylcholinesterase (AChE). In this study, the chemical compositions of 26 EOs prepared from white and black pepper collecting from 6 different cultivars were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 133 compounds were identified in the white and black pepper EOs. Monoterpenes and sesquiterpenes were found to be riched in these EOs, of which Ī±-pinene, Ī²-pinene, sabinene, 3-carene, limonene, and (E)-Ī²-caryophyllene were the major constituents. Most of pepper EOs showed potential AChE inhibitory activity with half-maximal inhibitory concentration (IC50) values in the range of 0.5-182.5 Āµg/mL. Comparison of chemical constitutes of pepper EOs from different cultivars suggested that Ī±-pinene, Ī²-pinene, and 3-carene with an IC50 value of 3.2, 53.3, and 2.9 Āµg/mL, respectively, might be used as Quality-marker (Q-marker) of pepper oil in inhibiting AChE
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