1,722,511 research outputs found
Xiao-Xu-Ming decoction extract regulates differentially expressed proteins in the hippocampus after chronic cerebral hypoperfusion
No full textXiao-Xu-Ming decoction has been widely used to treat stroke and sequelae of stroke. We have previously shown that the active fractions of Xiao-Xu-Ming decoction attenuate cerebral ischemic injury. However, the global protein profile and signaling conduction pathways regulated by Xiao-Xu-Ming decoction are still unclear. This study established a two-vessel occlusion rat model by bilateral common carotid artery occlusion. Rats were intragastrically administered 50 or 150 mg/kg Xiao-Xu-Ming decoction for 4 consecutive weeks. Learning and memory abilities were measured with Morris water maze. Motor ability was detected with prehensile test. Coordination ability was examined using the inclined screen test. Neuronal plasticity was observed by immunofluorescent staining. Differentially expressed proteins of rat hippocampus were analyzed by label-free quantitative proteomics. Real time-polymerase chain reaction and western blot assay were used to identify the changes in proteins. Results showed that Xiao-Xu-Ming decoction dramatically alleviated learning and memory deficits, and motor and coordination dysfunction, and increased the expression of microtubule-associated protein 2. Xiao-Xu-Ming decoction extract remarkably decreased 13 upregulated proteins and increased 39 downregulated proteins. The regulated proteins were mainly involved in oxidation reduction process, intracellular signaling cascade process, and protein catabolic process. The signaling pathways were mainly involved in ubiquitin mediated proteolysis and the phosphatidylinositol signaling system. Furthermore, there was an interaction among Rab2a, Ptpn1, Ppm1e, Cdk18, Gorasp2, Eps15, Capza2, Syngap1 and Mt-nd1. Protein analyses confirmed the changes in expression of MT-ND1. The current findings provide new insights into the molecular mechanisms of Xiao-Xu-Ming decoction extract’s effects on chronic cerebral hypoperfusion
Stabilisation of the hyperbolic equilibrium of high area-to-mass spacecraft
No full textIn this paper we propose the exploitation of anti-heliotropic orbits, corresponding to the hyperbolic solution of the J2 and solar radiation pressure dynamical system, as gateway orbits between the low-eccentricity orbits where atmospheric drag does not affect the motion and the high eccentricity orbits which enter in drag regime. The eccentricity can be maintained in the neighborhood of the unstable point by means of a controller preserving the Hamiltonian structure of the system. In this way, any initial eccentricity close to the equilibrium conditions will lead to a bound trajectory around the controlled elliptic equilibrium. By selecting the time the controller is turned off, one of the two unstable manifolds leaving the equilibrium point can be followed, leading the orbit to become circular of to increase its eccentricity until natural decay occurs
Control of parallel / modular converter system for electrical vehicle
No full textThis report presents an overview of work done and experience gained by the author during the Final Year Project (FYP) period.
The first part of the report covers the motivations of this project as well as the objective and scope. The main part of report shows the process of the project involved, which details with the design and simulation result of the control of two motor modules in Matlab Simulink Library. At last, the project is concluded and some future work is recommended.
The author was improved with his academic knowledge, trouble-shooting ability and teamwork corporation after this Final Year Project. This experience has prepared the author for his future study and career in the real industry.
Xu Ming
April, 2014Bachelor of Engineerin
The behaviour of soil behind full-height integral abutments
No full textCompared with conventional bridges, integral bridges have no bearings or joints between the decks and abutments, thus they can significantly reduce maintenance requirements and costs over the bridge life-time. The use of integral bridges has been encouraged over the past decade in the UK. However, because of the integral connection between thee superstructure and the abutments, the integral abutments are forced to move with the deck length change caused by daily and annual variations in the effective bridge temperature. As a consequence, the soil behind the abutment is subjected to temperature-induced cyclic loading from the abutment, and uncertainties have arisen about the ultimate magnitude of the lateral earth pressure behind integral abutments. To predict the lateral earth pressure behind integral abutments, a thorough understanding of the soil behaviour is essential. This research investigated the behaviour of a representative soil element at mid retained height under temperature-induced cyclic loading behind two typical types of full-height integral abutments. One is an embodied abutment constructed in in situ clayey ground, and the other is a frame abutment backfilled with granular material. An automated triaxial cyclic loading system has been developed. Undistributed Atherfield I Clay, Leighton Buzzard B sand and glass ballotini specimens have been subjected to the stress paths and levels of cyclic straining that a typical integral bridge abutment might impose on its retained soil. The results show that for stiff clay no lateral stress increase was observed, and the stress-strain behaviour and stiffness behaviour were not influenced by cycling. However, the coarse sand specimens experienced systematic increases in lateral stress for almost all cyclic strain levels, eventually reaching states of stress close to both active and passive. The underlying mechanisms of stress increase are explored, and it is concluded that particle shape is an important factor in determining the response of soil to this special type of loading. The implications for integral abutment design have been discussed.</p
The measurement of physical fields using optical fibres and fibre gratings
No full textIn this thesis a number of novel optical fibre and fibre Bragg grating sensors have been investigated for the purpose of measuring physical fields, particularly strain, temperature and pressure. These sensors are based on using short coherence length light source.Two laboratory prototypes of interferometric fibre pressure sensors have been demonstrated using a hollow-glass microsphere and optical fibres, respectively. These are intended for ultimate application as strain sensors for smart structures.A novel white-light polarimetric interrogator is demonstrated. The device consists of two equal lengths of highly-birefringent fibre, spliced with their polarization axes orthogonal. The dispersion effect on the responsivity of white-light interferometry is evaluated using a simplified transfer function. Using Jones matrix and Poincaré sphere analysis methods, the device performance has been discussed. Experimental results are presented by thermally-scanning the device for the interrogation of sensing interferometer.A fibre Bragg grating sensor for measuring pressure, strain and temperature is evaluated using measured data from over twenty different fibre gratings including Bragg gratings in highly-birefringent fibres. Intensive experimental results on thermally-induced decay of fibre gratings are presented for the evaluation of their potential in a wide variety of sensors and multiplexed systems.A first demonstration of a fibre grating interrogation system using an acousto-optic tunable filter is presented. The system involves frequency-shift-keying of the RF drive to the filter to track the measurand-induced wavelength shifts of multiplexed fibre gratings. An equivalent linear model has been developed to describe the operation of a wavelength tracking loop. Experimental results for both open-loop and close-loop operations are presented for strain and temperature measurements.Three novel techniques to resolve the thermal effect in strain measurement using fibre gratings are demonstrated. The first method involves using surface-mounted fibre grating pairs to compensate for thermal effects. The second technique uses two superimposed fibre gratings (single sensing element) to simultaneously measure strain and temperature. Last but not least by using a chirped Bragg grating in a tapered optical fibre as a strain sensing element, strain sensing can be made to be temperature-independent. Both theoretical analysis and experimental work are presented for these approaches
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Data_Sheet_1_Perturbed Lipidomic Profiles in Rats With Chronic Cerebral Ischemia Are Regulated by Xiao-Xu-Ming Decoction.pdf
No full textChronic cerebral ischemia (CCI) is a serious human health condition with lacking therapeutic agents. Moreover, its mechanism of action remains elusive, and thus novel treatment options are required. Lipid metabolism disorder are closely related to CCI. In this study, a CCI-rats model was established by the permanent occlusion of rat bilateral common carotid arteries, and then the rats were treated with a Xiao-Xu-Ming decoction (XXMD). Lipidomic profiling was conducted in both plasma and brain o determine the effects of the injury and therapy on lipid metabolism. Sphingolipid (particularly long acyl chain and total ceramides), glyceryl phosphatide, and glyceride profiles significantly changed in the brain after model induction and again after dosing. A total of 35 potential biomarkers were found in the brain and four were found in the plasma, representing both CCI injury and XXMD action. Correlations between endogenous lipids and exogenous XXMD compounds were analyzed using linear regression. Two exogenous compounds (cimifugin and 5-O-methylvisamminol) in the brain and 17 exogenous compounds in the plasma, which may represent the active constituents in XXMD, were significantly associated with lipid metabolism. This study provides a new perspective on the potential mechanism of CCI and its treatment with XXMD, as well as on discovering effective components in traditional Chinese medicines.</p
Perturbed Lipidomic Profiles in Rats With Chronic Cerebral Ischemia Are Regulated by Xiao-Xu-Ming Decoction
Get PDFChronic cerebral ischemia (CCI) is a serious human health condition with lacking therapeutic agents. Moreover, its mechanism of action remains elusive, and thus novel treatment options are required. Lipid metabolism disorder are closely related to CCI. In this study, a CCI-rats model was established by the permanent occlusion of rat bilateral common carotid arteries, and then the rats were treated with a Xiao-Xu-Ming decoction (XXMD). Lipidomic profiling was conducted in both plasma and brain o determine the effects of the injury and therapy on lipid metabolism. Sphingolipid (particularly long acyl chain and total ceramides), glyceryl phosphatide, and glyceride profiles significantly changed in the brain after model induction and again after dosing. A total of 35 potential biomarkers were found in the brain and four were found in the plasma, representing both CCI injury and XXMD action. Correlations between endogenous lipids and exogenous XXMD compounds were analyzed using linear regression. Two exogenous compounds (cimifugin and 5-O-methylvisamminol) in the brain and 17 exogenous compounds in the plasma, which may represent the active constituents in XXMD, were significantly associated with lipid metabolism. This study provides a new perspective on the potential mechanism of CCI and its treatment with XXMD, as well as on discovering effective components in traditional Chinese medicines
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