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An Appreciation of “A Psalm of Life  [PDF]
Xiaoqun Chen
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104489
Abstract:
“A Psalm of Life”, often subtitled “What the Heart of the Young Man Said to the Psalmist”, is a lyric written by Henry Wadsworth Longfellow, an American romantic poet [1]. In order to have an aesthetic appreciation, the author consults some literature and analyzes the poem in terms of its gist, theme, poetical features and practical significance. The conclusion is that full of aesthetics, this poem reveals an optimistic theme, appeals to readers’ minds and emotions and shows the poet’s noble spiritual world.
Both ischemic preconditioning and ghrelin administration protect hippocampus from ischemia/reperfusion and upregulate uncoupling protein-2
Yajun Liu, Lianbi Chen, Xiaoqun Xu, Eric Vicaut, Richard Sercombe
BMC Physiology , 2009, DOI: 10.1186/1472-6793-9-17
Abstract: After global forebrain ischemia (15 min) with 72 h reperfusion (I/R group), we found important neuronal lesion in the rat hippocampal CA1 region, which was reduced by a preceding 3-min preconditioning ischemia (IPC+I/R group), whereas the preconditioning stimulus alone (IPC group) had no effect. Compared to control, UCP2 protein labelling increased moderately in the I/R (+39%, NS) and IPC+I/R (+28%, NS) groups, and substantially in the IPC group (+339%, P < 0.05). Treatment with superoxide dismutase (10000 U/kg ip) at the time of a preconditioning ischemia greatly attenuated (-73%, P < 0.001) the increase in UCP2 staining at 72 h, implying a role of oxygen radicals in UCP2 induction.Hippocampal UCP2 mRNA showed a moderate increase in I/R (+33%, P < 0.05) and IPC+I/R (+40%, P < 0.05) groups versus control, and a large increase in the IPC group (+333%, P < 0.001). In ghrelin experiments, the I/R+ghrelin group (3 daily administrations) showed considerable protection of CA1 neurons versus I/R animals, and increased hippocampal UCP2 mRNA (+151%, P < 0.001).We confirm that IPC causes increased expression of UCP2 protein in vivo, at a moment appropriate for protection against I/R in the hippocampus. The two dissimilar protective strategies, IPC and ghrelin administration, were both associated with upregulated UCP2, suggesting that UCP2 may often represent a final common pathway in protection from I/R.Protection against ischemic lesion has been very extensively studied in the heart and brain. One powerful endogenous mechanism of protection present in these and other organs is ischemic preconditioning. This consists of a single or a series of brief, non-lethal ischemic periods which condition the tissue to resist against significant cell death when subsequently challenged by a normally lethal ischemia. Delayed protection, which is the subject of the present study, takes place from 12 h to 7 days after the preconditioning ischemia [1-5], and must involve transcriptional regul
A Review of Software Transactional Memory in Multicore Processors
Chen Fu,Zhibo Wu,Xiaoqun Wang,Xiaozong Yang
Information Technology Journal , 2009,
Abstract: The transactional memory in multicore processors has been a very hot research area over past several years. Many transactional memory systems have been proposed to solve the synchronization problem of multicore processors. Software transactional memory is one of the critical methods to ease parallel programming and improve the scalability in the environment with many cores. In this study, we give a review of the current software transactional memory systems for Multicore processors. Software transactional memory systems are classified into the following categories: transaction granularity, data organization, version management, conflict detection and synchronization. Finally, we discuss an active research challenge: whether strong isolation should be supported for the tradeoff between performance and semantics correctness in software transactional memory systems.
Mycobacterium tuberculosis Infection Is Associated with the Development of Erythema Nodosum and Nodular Vasculitis
Sheng’an Chen, Jiazhen Chen, Lianjun Chen, Qiao’an Zhang, Xiaoqun Luo, Wenhong Zhang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062653
Abstract: Background Mycobacterium tuberculosis (MTB) infection has been suggested to contribute to the pathogenesis of erythema nodosum (EN) and nodular vasculitis (NV), the classic forms of panniculitis. However, there is little evidence to demonstrate the presence of MTB in the skin lesions. This study is aimed at evaluating the association between MTB infection and the development of EN and NV in a Chinese population. Methods A total of 107 patients (36 EN, 27 NV, and 44 others) with vasculitis and 40 control cases with other skin diseases were recruited and their skin lesion samples were subjected to real time polymerase chain reaction (PCR) analysis of the IS6110 and mpt64 gene fragments of MTB. Their blood mononuclear cells were tested for MTB antigen-specific IFN-γ responses by QuantiFERON?-TB Gold In-Tube (IT) assays. Results PCR analysis revealed that 7/23 (30.4%) and 7/18 (38.9%) of the EN and NV samples were positive for the IS6110 DNA, respectively, which were significantly higher than 3/34 (8.8%) of other vasculitis (OV) and 3/40 (7.5%) of the control samples (p<0.05). The nested Real-Time PCR assay indicated that 6/7 (86%) of the IS6110-positive EN samples, all of the IS6110-positive NV and control samples, but only 1/3 of the IS6110-positive OV samples, were positive for the mpt64 gene. Similarly, 19/32 (59.4%) of the EN patients, 20/26 (76.9%) of the NV patients, and 17/36 (47.2%) of the OV patients were positive for MTB antigen-specific IFN-γ responses, which were significantly higher than 6/40 (15%) of the controls (p<0.05). Conclusion Our data strongly suggest that MTB infection and active TB are associated with the development of NV and EN in Chinese.
Low-Lying Energy Properties of a Frustrated Antiferromagnetic Spin-$\frac 1 2$ Ladder
Xiaoqun Wang
Physics , 1998,
Abstract: Using the Density Matrix Renormalization Group method, we determined the phase diagram of a frustrated antiferromagnetic spin-$\frac 1 2$ ladder at zero temperature. Two spin-gapped phases, the Haldane phase and the singlet phase, are identified. A phase transition between the two phases occurs at any non-zero value of frustration coupling $J_{\times}$. On the phase boundary, the spin gap vanishes for sufficiently small $J_{\times}$. Crossing this non-gapped line, the transition is of second order, while of first order for larger $J_{\times}$. Striking frustration effects are predicted for ladder materials.
A Kondo impurity in one dimensional correlated conduction electrons
Xiaoqun Wang
Physics , 1997, DOI: 10.1142/S0217984998000780
Abstract: A spin-1/2 magnetic impurity coupled to a one-dimensional correlated electron system have been studied by applying the density renormalization group method. The Kondo temperature is substantially enhanced by strong repulsive interactions in the chain, but changes non-monotonically in the case of electron attraction. The magnetization of the impurity at zero- temperature shows local Fermi liquid behavior.
Analysis on China’s Urban-Rural Integration: The Perspective of Path-Dependence  [PDF]
Xiaoqun Yang
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.42018
Abstract: With the development of the economy and society, to a certain extent, the development of the rural and the urban areas will integrate as the economic trend. The urban-rural dual structure in China has been mitigated in recent years, however, overall there are still a lot of differences be-tween the rural and urban areas and the gap between them cannot be ignored. The integrated development of rural and urban areas is at a low level and it is confronted with the negative effects of path-dependence. They are some factors now constraining the urban-rural integration, like the governance concept of separated administration in the urban and the rural areas, the impact of the choice of the initial institution and the negative impact of the urban and the rural subject behavior. Therefore, in order to break the path-dependence of urban-rural integration, innovation is needed in the concept of governance, institutional framework, motivation system, cooperation mechanism and so on.
Transient Focal Cerebral Ischemia/Reperfusion Induces Early and Chronic Axonal Changes in Rats: Its Importance for the Risk of Alzheimer's Disease
Qinan Zhang, Teng Gao, Yi Luo, Xijuan Chen, Ge Gao, Xiaoqun Gao, Yiwu Zhou, Jiapei Dai
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033722
Abstract: The dementia of Alzheimer's type and brain ischemia are known to increase at comparable rates with age. Recent advances suggest that cerebral ischemia may contribute to the pathogenesis of Alzheimer's disease (AD), however, the neuropathological relationship between these two disorders is largely unclear. It has been demonstrated that axonopathy, mainly manifesting as impairment of axonal transport and swelling of the axon and varicosity, is a prominent feature in AD and may play an important role in the neuropathological mechanisms in AD. In this study, we investigated the early and chronic changes of the axons of neurons in the different brain areas (cortex, hippocampus and striatum) using in vivo tracing technique and grading analysis method in a rat model of transient focal cerebral ischemia/reperfusion (middle cerebral artery occlusion, MCAO). In addition, the relationship between the changes of axons and the expression of β-amyloid 42 (Aβ42) and hyperphosphorylated Tau, which have been considered as the key neuropathological processes of AD, was analyzed by combining tracing technique with immunohistochemistry or western blotting. Subsequently, we found that transient cerebral ischemia/reperfusion produced obvious swelling of the axons and varicosities, from 6 hours after transient cerebral ischemia/reperfusion even up to 4 weeks. We could not observe Aβ plaques or overexpression of Aβ42 in the ischemic brain areas, however, the site-specific hyperphosphorylated Tau could be detected in the ischemic cortex. These results suggest that transient cerebral ischemia/reperfusion induce early and chronic axonal changes, which may be an important mechanism affecting the clinical outcome and possibly contributing to the development of AD after stroke.
Midgap States in Antiferromagnetic Heisenberg Chains with A Staggered Field
Jizhong Lou,Changfeng Chen,Jize Zhao,Xiaoqun Wang,Tao Xiang,Zhaobin Su,Lu Yu
Physics , 2005, DOI: 10.1103/PhysRevLett.94.217207
Abstract: We study low-energy excitations in antiferromagnetic Heisenberg chains with a staggered field which splits the spectrum into a longitudinal and a transverse branch. Bound states are found to exist inside the field induced gap in both branches. They originate from the edge effects and are inherent to spin-chain materials. The sine-Gordon scaling $h_s^{2/3}|\log h_s|^{1/6}$ ($h_s$: the staggered field) provides an accurate description for the gap and midgap energies in the transverse branch for $S=1/2$ and the midgap energies in both branches for $S=3/2$ over a wide range of magnetic field; however, it can fit other low-energy excitations only at much lower field. Moreover, the integer-spin S=1 chain displays scaling behavior that does not fit this scaling law. These results reveal intriguing features of magnetic excitations in spin-chain materials that deserve further investigation.
Antiferromagnetic Heisenberg ladders in a staggered magnetic field
Jize Zhao,Xiaoqun Wang,Tao Xiang,Zhaobin Su,Lu Yu,Jizhong Lou,Changfeng Chen
Physics , 2005, DOI: 10.1103/PhysRevB.73.012411
Abstract: We study the low-energy excitations of the spin-1/2 antiferromagnetic Heisenberg chain and $N$-leg ($N$=2, 3, 4) ladders in a staggered magnetic field $h_s$. We show that $h_s$ induces gap and midgap states in all the cases and examine their field scaling behavior. A modified boundary scheme is devised to extract accurate bulk excitation behavior. The gap values converge rapidly as $N$ increases, leading to a field scaling exponent $\gamma=1/2$ for both the longitudinal and transverse gaps of the square lattice ($N \to \infty$). The midgap states induced by the boundary edge effects share the bulk gap scaling exponents but their overall scaling behavior in the large-N limit needs further investigation.
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