Abstract:The neural ensemble aims to provide a mechanistic explanation of how groups of neurons acting together during a cognitive processing. It is significant to expressing neural ensemble at a higher precision when neural population activity data are recoded from experiment. In this article, we propose the use of sparse coding as a new methodology to address this issue by recording the activities of neurons in the rat prefrontal cortex during the working memory task in Y-maze. The time information of neural activity is summarized into bin counts using 200 milliseconds windows, and a sparse code for the bin-count matrix is found by means of a linear generative model. The meaningful components are extracted to reconstruct the input by an inverse of the sparsifying transform. None of the feature components are ignored or missed, as the number of the source components is greater than that of neurons. The reconstructed sparse neuronal activities are compared with rate coding. The recording twenty cases dealt show that, using sparse coding, it is possible to identify spatiotemporal patterns of neural activity in the form of reconstructed signal. The results indicate that the spatiotemporal location of neural ensemble could be more precisely detected, using sparse coding.

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	1. Neural ensemble sparse coding during working memory task in rat prefrontal cortex
	Xu Yunhua,Bai Wenwen,Tian Xin
	Basic Medicine 27 December 2010
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	Abstract:The neural ensemble aims to provide a mechanistic explanation of how groups of neurons acting together during a cognitive processing. It is significant to expressing neural ensemble at a higher precision when neural population activity data are recoded from experiment. In this article, we propose the use of sparse coding as a new methodology to address this issue by recording the activities of neurons in the rat prefrontal cortex during the working memory task in Y-maze. The time information of neural activity is summarized into bin counts using 200 milliseconds windows, and a sparse code for the bin-count matrix is found by means of a linear generative model. The meaningful components are extracted to reconstruct the input by an inverse of the sparsifying transform. None of the feature components are ignored or missed, as the number of the source components is greater than that of neurons. The reconstructed sparse neuronal activities are compared with rate coding. The recording twenty cases dealt show that, using sparse coding, it is possible to identify spatiotemporal patterns of neural activity in the form of reconstructed signal. The results indicate that the spatiotemporal location of neural ensemble could be more precisely detected, using sparse coding.
	TO cite this article:Xu Yunhua,Bai Wenwen,Tian Xin. Neural ensemble sparse coding during working memory task in rat prefrontal cortex[OL].[27 December 2010] http://en.paper.edu.cn/en_releasepaper/content/4401529


	2. Induced Pluripotent Stem (iPS) Cell：A novel potential resource for Hematopoietic Stem Cell Transplantation (HSCT)
	WANG Jing,CHEN Jing,PAN Xiongfei,BA Kai,GE Yuehua,LIN Yunfeng
	Basic Medicine 23 December 2010
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	Abstract:As a current procedure, hematopoietic stem cell transplantation (HSCT) has been applied for various blood diseases, such as leukemia and lymphoma. However, it sometimes causes significant immunological rejection, which may do harm to the recipients. Several researches have suggested that human iPS cells possess differentiation potentials to hematopoietic progenitor cells and lack of immunologic rejection. The hypothesis may be proposed that human iPS cells could be a novel potential resource for hematopoietic stem cell transplantation (HSCT). It is indicated that iPS cells will be a safer resource for research and clinic applications in future.
	TO cite this article:WANG Jing,CHEN Jing,PAN Xiongfei, et al. Induced Pluripotent Stem (iPS) Cell：A novel potential resource for Hematopoietic Stem Cell Transplantation (HSCT)[OL].[23 December 2010] http://en.paper.edu.cn/en_releasepaper/content/4400271

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	3. Rapid biomimetic mineralization of chitosan sponges with a facile method in ethanol/water mixed solution
	Li Lihua ,Zhou Changren
	Basic Medicine 18 May 2010
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	Abstract:Mineralization of biopolymers is a hot topic and a promising method for tissue engineering. In this study, biomimetic mineralization of chitosan sponges was performed in a large quantity with a rapid and facile approach. The calcium phosphate apatite was co-precipitated as the precursor for the formation of hydroxyapatite in mixed water-ethanol solution. The component and morphology of the apatite and the nanocomposite hybrid sponges were measured with XRD, TEM, FTIR and ESEM. The mechanism of nucleation and growth of crystals were discussed as well. Results revealed that chitosan matrix improved the crystalline quality of hydroxyapatite (HAP) crystals. With elongation of mineralization time, the mineral layers on the outer surface and inner section of chitosan sponges increased. The chitosan sponge or the microenvironment around it promoted the crystallites quality of HAP phase. Furthermore, the compressive strength and modulus of the HAP-chitosan bio-composites increased to 0.55 MPa and 29.29± 1.25 MPa respectively. Such one-pot approach might be extended to the mineralization of other biopolymers and will have a very broad application in the future.
	TO cite this article:Li Lihua ,Zhou Changren . Rapid biomimetic mineralization of chitosan sponges with a facile method in ethanol/water mixed solution[OL].[18 May 2010] http://en.paper.edu.cn/en_releasepaper/content/4372783


	4. Comparative quantification of microRNA in placenta and circulating nucleic acid isolated from maternal plasma and umbilical cord plasma
	Yang Qi ,Lu Jiafeng ,Ge Qinyu,Lu Zuhong
	Basic Medicine 18 August 2009
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	Abstract:The purpose of this study was to analyze the miRNA expression in placenta, maternal plasma and umbilical cord plasma of patients with mild and severe preeclampsia vs maternal plasma of normal pregnancies. Three families of miRNA was analyzed, which were miR-411, miR-154and miR-18a. The miRNA expression was compared between mPE and sPE in the same kind of sample, and also among the three kinds of sample. The result showed that miR-411 and miR-154 was downexpressed and miR-18a was upexpressed. It also showed that the expression of miRNA in placenta was consistent with maternal plasma, but showed more significant change in maternal plasma of sPE vs mPE. However, the expression of miRNA in umbilical cord plasma showed no markable relationship with placenta and maternal plasma.
	TO cite this article:Yang Qi ,Lu Jiafeng ,Ge Qinyu, et al. Comparative quantification of microRNA in placenta and circulating nucleic acid isolated from maternal plasma and umbilical cord plasma[OL].[18 August 2009] http://en.paper.edu.cn/en_releasepaper/content/34515


	5. Time–Frequency Coding via Wavelets Analysis for Bursting Spikes of Neuron Firing
	Xin Tian,Xinling Geng
	Basic Medicine 28 December 2007
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	Abstract:Bursting (spikes) shows very complex dynamics of firing activities of the neurons. The aim of this study is to investigate the coding details in time-frequency domain for bursting spikes using wavelet analysis, which will give a combinative neural code from both time and frequency domains. Data in this study is two types of the spikes: bursting and spiking simulatied from Chay model via 4-order R-K algorithm under different tasking conditions. The interspike intervals (ISI) are obtained through the spike series used for the neural coding. Mexican Hat (‘mexh’) wavelet is selected as mother wavelet used in this study. Neural coding of bursting under a 5-scale decomposition is performed and compared to that from temporal coding. The results of this study have demonstrated that time-frequency coding might be a more useful approach,and provide more details to neural coding for the bursting spikes than rate coding and temporal coding.
	TO cite this article:Xin Tian,Xinling Geng . Time–Frequency Coding via Wavelets Analysis for Bursting Spikes of Neuron Firing[OL].[28 December 2007] http://en.paper.edu.cn/en_releasepaper/content/17514


	6. Image reconstruction using local inverse
	shuangren Zhao
	Basic Medicine 26 September 2006
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	Abstract:Truncated projections can arise from a detector with limited field of view (LFOV). Truncation artifacts can be reduced through extrapolation methods; however the reconstructed images are often over-corrected or under-corrected. Recently an iterative reconstruction-reprojection algorithm was developed, which incorporated extrapolation with iterative algorithm. It gave the possibility to better reduce truncation artifacts compared to using extrapolation method alone. This paper builds a theoretic foundation for the above iterative reconstruction-reprojection algorithm. The theoretic foundation is suitable to parallel-beam fan-beam cone-beam computed tomography(CT). Two pre-assumptions are summarized from CT system. A truncation-artifact-free solution for the problem of LFOV is derived from these assumptions. The solution contains a “local inverse” of matrix. The local inverse of a matrix consists of the general inverse of the sub-matrices of the matrix. The solution can be approximately implemented as the iterative reconstruction-reprojection algorithm mentioned above.
	TO cite this article:shuangren Zhao. Image reconstruction using local inverse[OL].[26 September 2006] http://en.paper.edu.cn/en_releasepaper/content/8513


	7. EEG characteristics in frequency domain in synaptic dysfunction rat model
	han li ying,tian xin
	Basic Medicine 02 August 2006
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	Abstract:The aim of this study is to investigate the EEG characteristics in frequency domain in frontal lobe, occipital lobe and hippocampus, i.e. cognition-related cortex of synaptic dysfunction model rat. Firstly, synaptic dysfunction model was made via microinjecting Aβ1-40 into hippocampal CA1 area of rat. Morris water maze behavioral test performed to investigate the learning and memory function of model group. Secondly, EEG in the above areaa for two groups were recorded. The spectrum for two groups was performed and the characteristics in frequency domain were analyzed. Results are that (1) The average escape latency in 3rd, 4th, 5th and 6th training times of model group are higher than that of normal. The average escape latency of normal group had marked different between 2nd and 5th training time, while that of model group contrast between 2nd and 7th training time (P<0.05). Secondly, without platform, the platform quadrant time percentage of model group was lower than the control (P<0.05). (2) In model rat, α rhythm was slowing down; α-band power of EEG decreased with peek frequency left shifted nearly 2Hz. And the power of δ-band and θ-band in frontal lobe, occipital and hippocampus all increased with different extent, from 20% to 2-fold. The synaptic dysfunction model rats were made successfully by microinjecting Aβ1-40 method. The model rats show the decreased learning and memory dysfunction. EEG frequency spectrum features in model rat show slower alpha rhythm (frequency depressing) with power amplitude lower or loss, slow waves (delta and theta wave) increasing with higher power amplitude. These can be consistent with the EEG of Alzheimer’s disease patients. Such provide electrophysiological basis for further plasticity and nerve regeneration study on the impaired cortex with synaptic dysfunction.
	TO cite this article:han li ying,tian xin. EEG characteristics in frequency domain in synaptic dysfunction rat model[OL].[ 2 August 2006] http://en.paper.edu.cn/en_releasepaper/content/7787


	8. A PCR-based Technology for Quickly Screening of gDNA Library
	Zhao Yongxiang
	Basic Medicine 03 July 2006
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	Abstract:Objective: To explore the feasibility of quickly screening of gDNA library with PCR technique. Methods: We adopted porcine α-1,3GT cDNA fragment as the probe, used the primers synthesized by the specific sequence on cDNA to carry out α-1,3GT gene screening of porcine gDNA library by combining PCR and in situ plaque hybridization, and then performed enzymic digestion, southern blot, sequencing and fluorescence in situ hybridization for location. Results: After having finished one-time hybridization and one-time PCR, we obtained 7 positive monoclones with very strong signals, and each insert length of them is over 8kb, including the third intron. Moreover, 3 tested clones among them contain the third and fourth exons according to the sequencing results, and FISH mapped the inserts of the 3 clones to pig chromosome 1q2.10-q2.11. Conclusion: PCR could be applicable to the quick screening of DNA library and much simpler than the conventional in situ plaque hybridization only used.
	TO cite this article:Zhao Yongxiang. A PCR-based Technology for Quickly Screening of gDNA Library[OL].[ 3 July 2006] http://en.paper.edu.cn/en_releasepaper/content/7438


	9. Image Reconstruction for Fan Beam X-Ray Tomography Using General Hankel Transform Pair (2)
	Zhao Shuangren
	Basic Medicine 27 June 2006
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	Abstract:A new transform pair has been introduced for the fan-beam image reconstruction[10]. This new integral transform plays the same role as the Hankel ( Fourier Bessel) transform in the parallel beam case and includes the Hankel transform as a special case. In this paper we develop this method for the equal-angle fan beam geometry. We call this new pair the General Hankel transform which gives transform and inverse transform from an object function f(r,beta) to fan beam projections R_beta(gamma). One member of the pair can be used to calculate projection data for simulation; the other can be used as an algorithm for fan beam reconstruction without interpolation in polar coordinates. Compared with other algorithms for fan beam reconstruction the general Hankel transform method is especially useful when f(r,beta) the image to be reconstructed, has only low frequencies in the theta angle direction and only few projections are available.
	TO cite this article:Zhao Shuangren . Image Reconstruction for Fan Beam X-Ray Tomography Using General Hankel Transform Pair (2)[OL].[27 June 2006] http://en.paper.edu.cn/en_releasepaper/content/7335


	10. Image Reconstruction for Fan Beam X-Ray Tomography Using General Hankel Transform Pair (1)
	Zhao Shuangren
	Basic Medicine 24 April 2006
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	Abstract:A new integral transform pair has been introduced for the reconstruction of slices from fan beam projection data. This integral transform plays the same role as the Hankel transform (or Fourier Bessel transform) in the parallel beam case and includes the Hankel transform as a special case. The relations between the new integral transform and the Hankel transform pair are derived and the implementation of the algorithm is described. Memory space requirements and speed of the transform are discussed and the advantage of precalculations are mentioned. The transform pair is especially useful in case the two dimensional object slice to be reconstructed has only few low frequency components in the azimutal direction. Furthermore the method is capable of treating the case where non analytic a priori information is to be taken into account. In this case projections into the measurement directions are performed and the differences between these projection data and the measured data are reconstructed in order to improve the object data. Alternating transformations between projection and object space are efficient and fast. Finally some results of simulations including the influence of noise are shown and possible applications of the method are discussed.
	TO cite this article:Zhao Shuangren . Image Reconstruction for Fan Beam X-Ray Tomography Using General Hankel Transform Pair (1)[OL].[24 April 2006] http://en.paper.edu.cn/en_releasepaper/content/6367

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