MMSE equalization of downlink CDMA channel utilizing unused orthogonal spreading sequences

For the code division multiple access (CDMA) downlink channel, the chip-level equalization has been considered in this paper. There is no interference after despreading if all spreading codes are orthogonal, as in IS-95. However, it cannot be true for a frequency-selective fading channel. In this case, the chip-level equalization can be applied to restore the orthogonality. We investigate the chip-level equalization using finite impulse response (FIR) equalizers for the mobile station with multiple receive antennas. A blind approach and the minimum mean square error (MMSE) approach with code-multiplexed pilot are considered. A generalized MMSE equalization, which combines the MMSE and blind approaches together, is also investigated. It is shown that the generalized MMSE equalizer can effectively increase the number of samples to track the variation of channel and thereby performs better when the coherence time is small. In addition, we derive closed-form solutions of the blind, MMSE, and generalized MMSE equalizers for given channels.     

MIMO-OFDM channel estimation method utilizing correlation in time domain for B3G-TDD uplink

This article proposes a simple pilot-aided channel estimation method based on correlation in time domain for multiple-input and multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. Pilot symbols in all transmit antennas are generated from different circular shifting of a certain sequence. Through once correlation, the receiver can obtain time-domain pulse responses for channel fading from all transmit antennas to a certain receive antenna, from which channel estimation in frequency domain can be obtained. Beyond 3G time-division duplex (B3G-TDD) uplink is introduced, and the channel estimation method is used in it. Theoretical analysis and simulation are both carried out. Mean square error (MSE) performance shows that the method can exhibit precise estimation. Complexity analysis proves it requires very low complexity. System simulation result shows that it guarantees the performance of B3G-TDD uplink very well.     

Functional analysis of mammalian genes using amphibian embryonic cells

We describe a method that contributes to the analysis of the functions of mammalian genes by the use of amphibian embryos and electron microscopy. Following forced expression of specific mammalian genes in amphibian embryos, we attempted to deduce the function of each gene from the ultrastructural changes in cell organelles caused by its overexpression. This method has been applied to the analysis of the functions of genes isolated from mammalian skeletal muscle and the results have shown it to be an effective technique for such studies. We present the results of our experimental studies using this method and discuss its usefulness in analyzing mammalians genes.     

Focusing of biological cells utilizing negative dielectrophoretic force generated by insulating structures

The main purpose of the present study is to design an insulator-based dielectrophoretic microdevice with effective focusing of biological cells. The cells are introduced into the microchannel and pre-confined hydrodynamically by the funnel-shaped insulating structures close to the inlet. The cells are, therefore, repelled toward the center of the microchannel by the negative dielectrophoretic forces generated by the insulating structures. The increase in the applied electric field significantly enhances the performance of focusing. Furthermore, decreasing inlet velocity increases the efficiency of focusing because the higher velocity results in more lateral expansion. Preliminary experiments employing viable HeLa cells are conducted in order to demonstrate the feasibility of the present design. Experimental results indicate that the performance of focusing increases with the strength of the electric field applied or with a decrease in the inlet velocity. The experimental results agree with the predictions by numerical simulations. The design proposed herein has no need for complicated flow controls to focus the cells.     

Improvement of kink and beam steering characteristics of 0.98-μmGaInAs-GaInP high-power lasers utilizing channel ion implantation

We demonstrate a kink and beam steering free operation of 0.98-μm GaInAs-GaInP high-power ridge waveguide (RW) lasers utilizing channel ion implantation. The ion-implanted regions along the both sides of the ridge effectively suppressed the excitation of higher order lateral modes, which causes beam steering and kink. The maximum power without beam steering and kink has been achieved over 250 mW for channel ion-implanted RW lasers with 1.8-3.7-μm ridge width, compared to 120-mW maximum power without the channel ion implantation     

FlAsh在标记细胞内蛋白质中的应用

绿色荧光蛋白质GFP在生物学上已经得到广泛应用，它可以作为标记物来研究活细胞内基因、蛋白质的表达和功能定位。然而GFP无法分辨新生成的与原有的蛋白质分子，且GFP和它的不同突变体(25-27KD)的蛋白质，通常要大于我们的靶蛋白质。分子量较大的GFP有可能会干扰其他结合蛋     

Fabrication of sub-wavelength antireflective structures in solar cells by utilizing modified illumination and defocus techniques in optical lithography

We demonstrate a simple method, which is combining modified illumination and defocus techniques to fabricate sub-wavelength antireflective structures for solar cells. The optimum pyramid resist and silicon profiles can be obtained after exposure, development and common dry etching processes. The reflection and transmission properties are analyzed by the rigorous coupled-wave analysis in two-dimensional microstructure and find the reflectance is dramatically increased as consideration of all diffraction orders. Therefore, patterning the sub-wavelength texturing structures for eliminating the diffraction order light is important. Patterning sub-wavelength structures should use the short wavelength combining defocus exposure or using a suitable modified illumination exposure system. The optimized pyramid structures are simulated in dosage-focus matrix with different types of light source. Results show the quadrupole modified illumination system with large process latitude is suitable for patterning sub-wavelength pyramid structures.     

Postprocessing of FDTD solutions for precise calculations of eigenfrequencies of photonic periodic structures utilizing the variational expression

This paper presents a method that improves by orders of magnitude the accuracy of the finite-difference time-domain (FDTD)-calculated eigenfrequencies of photonic crystals. The method utilizes a variational expression for the eigenfrequencies of periodic structures. Applications to perfect crystals, waveguides, and resonant cavities are demonstrated. The paper confirms that the method can reduce the computational time by more than 90% while obtaining accuracy in frequency comparable to that obtained solely by the conventional FDTD method.     

Improved performance of inverted polymer solar cells by utilizing alcohol-soluble oligofluorenes as efficient cathode interlayers

Two star-shaped oligofluorenes with hexakis(fluoren-2-yl)benzene as core are designed and synthesized, namely Tn0 and Tn1. Diethylamino groups are attached to the side chain of fluorene units of Tn0 and Tn1 and enable them alcohol solubility, additional hydrophobic nhexyl chains are grafted on the π-extended fluorene arms of Tn1. Power conversion efficiency (PCE) as high as 8.62% and 8.80% are achieved when utilizing Tn0 and Tn1 as cathode interlayers in inverted polymer solar cells, respectively. The work function of ITO effectively decreased by introducing interlayer, resulting in high Voc of the device, besides, the wetting properties of the interlayers can be tuned by modifying the oligofluorenes with π-extended structure, and the more hydrophobic interlayer will benefit the device performance with enhanced Jsc and FF.     

睾酮对内皮细胞表达细胞因子的影响

针对现有测试技术不能直接获得纳米尺度铁电薄膜电滞回线的问题,提出了将原子力显微镜与铁电分析仪连用的方法,研究了锆钛酸铅(PZT)薄膜样品的电滞回线.结果表明,应用铁电分析仪与原子力显微镜联用的测试技术能表征铁电薄膜的电滞回线,在无顶电极测试条件下,测试得到的电滞回线很不对称,且剩余极化值较大.     

Monitoring of electrocardiograms in bed without utilizing bodysurface electrodes

A system by which an electrocardiogram can be obtained without the individual's awareness was investigation. It involves placing the electrodes in a bed set composed of electrically conductive textiles. Electrocardiograms were successfully obtained during sleep. However, during the periods of the subject's movement in bed, the waveform became unrecognizable     

Modifying effects of recombinant tumor necrosis factor on the metastatic potential of tumor cells

Cells of the Lewis lung carcinoma (3LL), B16 melanoma and Ehrlich carcinoma pre-treated in vitro by a recombinant tumour necrosis factor (rTNF) were studied for their spontaneous and experimental metastatic spreading. The rTNF (1000 u/ml) was determined to stimulate a metastatic potential of the Lewis carcinoma cells after their treatment with the factor for 6 h and, vice versa, to inhibit it after 96 h prolonged treatment. The efficacy of the stimulating effect of rTNF on a metastatic spreading depends on the peculiarities of the studied cells.     

Conductometric Titration for the Prediction of Conductivity in Solutions with Polymeric Membranes

The analytical technique of conductometric titration is used to characterize polymeric materials. This technique allows obtaining the polymer dry weight capacity (DWC) and the extent of reaction and establishing the optimal number of water molecules per sulfonic groups. In this particular case the polymer material under study was Nafion 117. Two different reactions were made: Neutralization and exchange. Both of them allow obtaining the same result. Conductometric titrations could be considered as a good method to study the neutralization and exchange reactions for polymeric materials used in fuel cells or electrolyzers. The implementation of this analytical technique allows reducing operation time of those types of materials. The waiting time between determinations permits to say that the amount of reactant consumed and products obtained were the same after each addition of titrant.     

非理想载波同步下OFDM快衰落信道的稀疏与感知

针对稀疏导频 OFDM 系统,提出非理想载波同步 OFDM 快衰落信道稀疏表示与感知方法。首先提出了一种稀疏化信道核向量的广义信道冲激响应矩阵稀疏化表示方法;推导了稀疏导频快衰落信道估计压缩感知模型;利用OMP算法重构稀疏化信道核向量与广义信道冲激响应矩阵,从而完成非理想载波同步下的 OFDM 快衰落信道估计。仿真结果表明,该算法能有效降低非理想载波同步的稀疏导频 OFDM 系统的误码率。     

鼠重组腺病毒介导的骨形成蛋白-9转染大鼠牙囊干细胞的实验研究

目的：探讨鼠重组腺病毒介导的骨形成蛋白9基因转染大鼠牙囊干细胞的可行性及其转染后的成骨作用,以获得可用于牙周骨组织再生工程的基因修饰的种子细胞。方法：取大鼠下颌骨,解剖显微镜下体外分离培养纯化鉴定牙囊干细胞,腺病毒介导的骨形成蛋白9基因转染第三代牙囊干细胞,并设立空白对照组,绿色荧光病毒组（GFP组）。通过观察细胞形态及生长曲线变化,荧光显微镜及RT—PCR检测转染后骨形成蛋白9基因mRNA的表达,碱性磷酸酶及钙茜素红染色测定转染后牙囊干细胞的成骨活性。结果：与未转染对照组比较,转染组细胞转染2周后形成钙化结节,停滞期延长,数量轻度下降,倍增时间延长。牙囊干细胞转染骨形成蛋白9基因后12h后即有荧光表达,转染3,6,9,12d后骨形成蛋白9mRNA均呈阳性表达且逐渐增强,未转染对照组呈阴性。转染组碱性磷酸酶活性随转染时间的延长呈升高趋势,ALP染色及茜素红钙结节染色为阳性：未转染对照组碱性磷酸酶染色及钙茜素红染色均呈弱阳性表达,转染组显著高于未转染组。结论：鼠重组腺病毒介导的RBMP-9基因可以成功地转染大鼠牙囊干细胞,转染后牙囊干细胞高表达骨形成蛋白9,且具有明显的成骨作用。     

Real-time monitoring in fabrication of PPKTP crystals utilizing electro-optical effect

Compared with other nonlinear optical materials, KTP crystals have prominent advantages.However, they also have a high conductivity and become difficult to efficiently control domain-reverse with the conventional method, due to the existence of ionic current. To conquer the difficulty, it is necessary to monitor the polarization-reversal process of KTP crystals in real time. The real-time monitoring method in the fabrication of PPKTP, short for periodically-poled KTiOPO4, is carried out by utilizing electro-optical effect. The principle is analyzed theoretically and the result demonstrates the validity of the method experimentally. Compared with the result without using the monitoring method, the conversion efficiency of PPKTP crystal increases by many times. It is proved that this method can be used to enhance the quality and repeatability of PPKTP fabrication, and is also effective to examine the quality of PPKTP crystals.     

A model for calculating channel share of 802.11 access points with overlapping wireless cells

Consider a collection of 802.11 access points. Each serves as the gateway to the Internet for clients in its WiFi cell. These cells have an arbitrary interference pattern, and reception at a client may be corrupted by transmissions nearby. The popularity of WiFi has made such dense deployment increasingly common. As interference can seriously degrade performance, there is much interest in optimizing the configuration of these cells. One factor to consider in optimization is channel share, defined as the useful fraction of channel bandwidth that an access point gets when there is downlink traffic saturation. Interference affects channel share on the sender side through carrier sensing and transmission deferral, and on the receiver side through collisions, which result in exponential backoff and retransmission. There exists a simple, “back-of-the-envelope” (BoE) technique to model the impact of pairwise sender-side interference. This paper tackles the harder task of determining the impact of receiver-side and non-pairwise sender-side interference. It proposes a technique for modeling the channel share of wireless links, and the accuracy is demonstrated with Qualnet simulation.     

Evidence for voltage-gated potassium channel beta-subunits with oxidoreductase motifs in human and rodent pancreatic beta cells

Voltage-gated K(+) channel alpha subunits (K(V) alpha) have been previously identified in pancreatic islet beta-cells where it has been suggested they have a role in membrane repolarization and insulin secretion. Here we report the cloning of the three mammalian K(V) beta subunits, including splice variants of these subunits, from both human and rat pancreatic islets and from the rat insulinoma cell line INS-1. Two of the splice variants, K(V) beta1a and K(V) beta3, previously reported to be neuronal tissue specific, are expressed in islets and INS-1 cells. In addition, a splice variant of K(V) beta2 that lacks two potential protein kinase C phosphorylation sites at the amino terminus is present. Immunoblot analysis suggests a high level of K(V) beta2 subunit protein in rat pancreatic islets and immunoprecipitation with anti-K(V) beta2 antibody pulls down a protein from INS-1 cells that reacts with anti-aldose reductase antibody. The K(V) beta subunits, which are attached to the cytoplasmic face of the alpha subunits and are members of the aldose reductase superfamily of NADPH oxidoreductases, may have an as yet undetermined role in the regulation of insulin secretion by the intracellular redox potential. Finally, we suggest that a systematic nomenclature for K(V) beta subunits first proposed by McCormack et al. be adopted for this family of potassium channel subunits as it corresponds with the nomenclature used for their cognate K(V) alpha subunits.