Jie Zhu
Yanjiong Chen
Na Zhao
Guofen Cao
Yonghui Dang
Wei Han
Ming Xu and Teng Chen
Persistent changes in behavior and psychological function that occur as a consequence of exposure to drugs of abuse are thought to be mediated by the structural plasticity of specific neural circuits such as the brain's dopamine (DA) system. Changes in dendritic morphology in the nucleus accumbens (NAc) accompany drug-induced enduring behavioral and molecular changes, yet ultrastructural changes in synapses following repeated exposure to drugs have not been well studied. The current study examines the role of DA D3 receptors in modulating locomotor activity induced by both acute and repeated methamphetamine (METH) administration and accompanying ultrastructural plasticity in the shell of NAc in mice. We found that D3 receptor mutant (D3−/−) mice exhibited attenuated acute locomotor responses as well as the development of behavioral sensitization to METH compared with wild-type mice. In the absence of obvious neurotoxic effects, METH induced similar increases in synaptic density in the shell of NAc in both wild-type and D3−/− mice. These results suggest that D3 receptors modulate locomotor responses to both acute and repeated METH treatment. In contrast, the D3 receptor is not obviously involved in modulating baseline or METH-induced ultrastructural changes in the NAc shell.
Jie Zhu
Yanjiong Chen
Na Zhao
Guofen Cao
Yonghui Dang
Wei Han
Ming Xu
Teng Chen
Persistent changes in behavior and psychological function that occur as a consequence of exposure to drugs of abuse are thought to be mediated by the structural plasticity of specific neural circuits such as the brain's dopamine (DA) system. Changes in dendritic morphology in the nucleus accumbens (NAc) accompany drug-induced enduring behavioral and molecular changes, yet ultrastructural changes in synapses following repeated exposure to drugs have not been well studied. The current study examines the role of DA D3 receptors in modulating locomotor activity induced by both acute and repeated methamphetamine (METH) administration and accompanying ultrastructural plasticity in the shell of NAc in mice. We found that D3 receptor mutant (D3−/−) mice exhibited attenuated acute locomotor responses as well as the development of behavioral sensitization to METH compared with wild-type mice. In the absence of obvious neurotoxic effects, METH induced similar increases in synaptic density in the shell of NAc in both wild-type and D3−/− mice. These results suggest that D3 receptors modulate locomotor responses to both acute and repeated METH treatment. In contrast, the D3 receptor is not obviously involved in modulating baseline or METH-induced ultrastructural changes in the NAc shell.
Experimental autoimmune neuritis (EAN) is a CD4+ T cell-mediated, inflammatory demyelinating disease of the peripheral nervous system (PNS) that serves as a model for Guillain-Barre syndrome (GBS) in humans. Various mouse and rat strains show different susceptibilities to EAN that can be induced by immunization with bovine PNS myelin (BPM) + Freund's complete adjuvant (FCA). We examined PNS-induced T and B cell responses and cytokine protein production as well as mRNA expression to study the mechanisms behind susceptibility to EAN in Lewis rats and resistance in Sprague-Dawley (SD) rats. Lewis rats with EAN have elevated PNS myelin-reactive interferon-gamma (IFN-gamma) production, TNF-alpha mRNA expression, and increased B cell responses to PNS myelin antigens, but low PNS myelin-reactive transforming growth factor-beta (TGF-beta) and interleukin (IL)-10 mRNA expression in lymph node mononuclear cells (MNC). In contrast, resistance to EAN in SD rats is associated with reduced BPM and P2 peptide-reactive IFN-gamma production, TNF-alpha mRNA expression, and suppressed B cell responses to PNS myelin antigens as well as up-regulation of TGF-beta and IL-10 mRNA expression. Resistance to EAN is also associated with low-grade inflammation or absence of histological evidence of EAN. These results suggest that differential autoreactive T and B cells responses to PNS myelin antigens are strain specific, and the susceptibility to EAN is related to quantitative rather than qualitative differences in distribution between proinflammatory and anti-inflammatory cytokines.
Zheng Li
Dan-Qing Yang
Shi-Lei Liu
Si-Yuan Yu
Ming-Hui Lu
Jie Zhu
Shan-Tao Zhang
Ming-Wei Zhu
Xia-Sheng Guo
Hao-Dong Wu
Xin-Long Wang
Yan-Feng Chen
High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding −6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems.
Abstract The effects of the periodical turbulence and pressure fluctuation on suction surface heat transfer over airfoils of a row of rotor blades with a certain type have been investigated numerically in this paper. The calculation is performed using ν 2 ¯ − f model with the numerical results of pressure fluctuation and heat transfer performance over 4 sample points being analyzed and compared with existing experimental data. It shows that the static pressure change has significant impact on heat transfer performance of the fore suction surface, especially in the active region of the shock waves formed from the trailing edge of upstream nuzzles. While, for the rear suction surface, the flow turbulence contributes more to the heat transfer change over the surface, due to the reduced pressure oscillation through this region. Phase shifted phenomenon across the surface can be observed for both pressure and heat transfer parameters, which should be a result of turbulence migration and wake passing across the airfoil.
Jinghong Hao
Fengying Gu
Jie Zhu
Shaowei Lu
YiFei Liu
Yunfei Li
Weizhi Chen
Liping Wang
Shuangxi Fan
Cory J Xian
Due to the importance and complexity of photo assimilate transport in raffinose family oligosaccharide (RFO)-transporting plants such as melon; it is important to study the features of the transport structure (phloem) particularly of the lateral branches connecting the source leaves and the sink fruits; and its responses to environmental challenges. Currently; it is unclear to what extents the cold environmental temperature stress would alter the phloem ultrastructure and RFO accumulation in RFO-transporting plants. In this study; we firstly utilized electron microscopy to investigate the changes in the phloem ultrastructure of lateral branches and RFO accumulation in melons after being subjected to low night temperatures (12°C and 9°C). The results demonstrated that exposure to 9°C and 12°C altered the ultrastructure of the phloem; with the effect of 9°C being more obvious. The most obvious change was the appearance of plasma membrane invaginations in 99% companion cells and intermediary cells. In addition; phloem parenchyma cells contained chloroplasts with increased amounts of starch grains; sparse cytoplasm and reduced numbers of mitochondria. In the intermediary cells; the volume of cytoplasm was reduced by 50%; and the central vacuole was present. Moreover; the treatment at 9°C during the night led to RFO accumulation in the vascular bundles of the lateral branches and fruit carpopodiums. These ultrastructural changes of the transport structure (phloem) following the treatment at 9°C represented adaptive responses of melons to low temperature stresses. Future studies are required to examine whether these responses may affect phloem transport.
Shujuan Li
Tao Jin
Hongliang Zhang
Hong Yu
Fanhua Meng
Hernán Concha Quezada
Jie Zhu
The Guillain-Barré syndrome (GBS) is considered a T helper 1 (Th1) cells-mediated acute inflammatory peripheral neuropathy. However; some changes in GBS could not be explained completely by Th1 cells pathogenic role. Recently; Th17 cells have been identified and can mediate tissue inflammation and autoimmune response. Therefore; a study on the role of Th17 and Th22 cells and their cytokines in GBS is necessary for exploring the pathogenesis of GBS. Here; we detected the frequency of Th1; Th17; and Th22 cells by using 4-color flow cytometry and we detected the plasma levels of IL-17 and IL-22 by ELISA in GBS patients; relapsing-remitting multiple sclerosis patients at the acute phase of relapse; viral encephalitis or meningitis patients and healthy controls. Our data showed that the frequency of circulating Th1; Th17; and Th22 cells was significantly increased in GBS patients. The plasma levels of IL-17 and IL-22 in GBS and relapsing-remitting multiple sclerosis at the acute phase of relapse were also markedly elevated. Enhanced circulating Th22 cells were correlated with GBS severity. Intravenous immunoglobulin therapy downregulated Th17; and Th22 cells and the plasma levels of IL-17 and IL-22 in GBS patients. Th17 and Th22 cells may be involved in the pathogenesis of GBS; and intravenous immunoglobulin mediates therapeutic effects by downregulating these cells and their cytokines.
In this paper; we describe our duration model techniques in HMM based speech recognizer. With this approach; a large amount of deletion and insertion errors can be reduced in Mandarin continuous digits recognizer. We address a simple duration penalty function; which can be explicitly combined into Viterbi-Beam search with negligible incremental computation overload. Different parametric distributions are investigated to accurately approximate the syllable-level duration information. A relative Rate of Speech (ROS) based duration normalization scheme is proposed to eliminate variation caused by different speaking rate. In order to directly incorporate this normalization strategy; an online dynamic ROS estimation method is introduced into real-time recognition application. Experimental results demonstrated significant performance improvement has been achieved. The word error rate (WER) was reduced 52.1%; compared with our baseline recognition system.
Nan Dong
Jie Zhu
Wei Han
Shuai Wang
Zhilan Yan
Dongliang Ma
Eyleen L.K. Goh
Teng Chen
Abstract Prenatal drug exposure altered cognitive function in individuals, and may also impact their offspring's susceptibility to cognitive impairment. The high incidence of methamphetamine (METH) abuse among adolescents and women of childbearing age elevates the importance to determine the influence of maternal METH exposure on cognitive functions in the descendants. We hypothesized that maternal METH exposure affects cognitive behavior in offspring mice by disrupting gene expression associated with neural development. Here, female C57BL/6 mice were exposed to intermittent escalating doses of METH or saline from adolescence to adulthood, and then continued through pregnancy. Interestingly, male but not female offspring exhibited impaired short-term recognition memory and long-term spatial memory retention in novel object recognition and Morris water maze test respectively. Additionally, maternal METH exposure altered neurodevelopmental genes in both male and female offspring, and 12 differentially expressed genes between male and female were observed in the HPC and NAc regions. These differentially expressed genes are involved in neurogenesis, axon guidance, neuron migration and synapse of neural development circuits. Our observations suggest that maternal METH exposure induced differential expression patterns of neurodevelopment-related genes in the HPC and NAc of male and female mice, which may underlie the different cognitive behavior phenotypes in both genders. Highlights • Maternal METH exposure impaired recognition memory in male but not female offspring. • Maternal METH exposure impaired spatial memory in male but not female offspring. • Maternal METH exposure altered neurodevelopmental gene expression in offspring mice. • 12 neurodevelopmental genes expressed differentially in male and female offspring.
Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is potentially lethal, but it is also a treatable autoimmune disorder characterized by prominent psychiatric and neurologic symptoms. It is often accompanied with teratoma or other neoplasm, especially in female patients. Anti-NMDAR antibodies in cerebrospinal fluid (CSF) and serum are characteristic features of the disease, thereby suggesting a pathogenic role in the disease. Here, we summarize recent studies that have clearly documented that both clinical manifestations and the antibodies may contribute to early diagnosis and multidisciplinary care. The clinical course of the disorder is reversible and the relapse could occur in some patients. Anti-NMDAR encephalitis coexisting with demyelinating disorders makes the diagnosis more complex; thus, clinicians should be aware of the overlapping diseases.
Abstract Thermoelectric (TE) technology is regarded as alternative and environmentally friendly technology for harvesting and recovering heat which is directly converted into electrical energy using thermoelectric generators (TEG). Conversely, Peltier coolers and heaters are utilised to convert electrical energy into heat energy for cooling and heating purposes The main challenge lying behind the TE technology is the low efficiency of these devices mainly due to low figure of merit (ZT) of the materials used in making them. The objective of this work is to carry out a comprehensive review of TE technology encompassing the materials, applications, modelling techniques and performance improvement. The paper has covered a wide range of topics related to TE technology subject area including the output power conditioning techniques. It is observed that the intensified research into TE technology has led to an outstanding increase in ZT, rendering the use TE devices in diversified application a reality. The performance improvements of TE devices have been mainly contributed by improved TE material research, TE device geometrical adjustments, design of integrated TE devices as well as the use of advanced TE mathematical models which have facilitated appropriate segmentation of TE modules using different materials. TE devices are observed to have booming applications in cooling, heating, electric power generation as well as hybrid applications. With the generation of electrical energy using TEG, not only does the waste heat provide heat source but also other energy sources like solar, geothermal, biomass, infra-red radiation have gained increased utilization in TE based systems. However, the main challenge remains in striking the balance between the conflicting parameters; ZT and power factor, when designing and optimizing advanced TE materials. Hence more research is necessary to overcome this and other challenge so that the performance TE device can be improved further.
Kai Feng
Minghui Shi
Tao Gong
Yuanyuan Liu
Jie Zhu
Highlights • A novel squeeze film bearing with flexure pivot-tilting pads is manufactured and tested. • A theoretical model that combines models for squeeze film and flexure pivot-tilting pads is presented. • Float characteristics of our proposed squeeze film bearing are predicted and analyzed. • Effect of bearing structure parameters on squeeze effect is investigated. Abstract This study proposes a novel squeeze-film air bearing based on near-field acoustic levitation technology. Unlike previous squeeze-film bearings, the new bearing employs flexure pivot-tilting pads as vibration surfaces and provides higher vibration amplitude and better stability for rotor systems. The flexure pad structure eases processing and adapts well to squeeze action. This paper presents a theoretical model of the new bearing that combines models for squeeze film and flexure pivot-tilting pads to study the float characteristics. Resonant frequency and vibration mode of the bearing were obtained by using finite element modelling and validated by experimental results. The authors investigated the mechanism of pressure generation of squeeze film and pad movement. The load carrying capacity of the bearing was experimentally investigated. Numerical and experimental results show that the proposed bearing is a feasible non-contact bearing for high-speed and high-precision rotating machineries. Graphical abstract This study proposes a novel squeeze-film air bearing based on near-field acoustic levitation technology. This paper presents a theoretical model that combines models for squeeze film and flexure pivot-tilting pads. Float characteristics of the bearing were theoretically and experimentally investigated. Image, graphical abstract