The capacity of the quantum depolarizing channel

The information-carrying capacity of the d-dimensional depolarizing channel is computed. It is shown that this capacity can be achieved by encoding messages as products of pure states belonging to an orthonormal basis of the state space, and using measurements which are products of projections onto this same orthonormal basis. In other words, neither entangled signal states nor entangled measurements give any advantage for information capacity. The result follows from an additivity theorem for the product channel /spl Delta//spl ominus//spl Psi/, where /spl Delta/ is the depolarizing channel and /spl Psi/ is a completely arbitrary channel. We establish the Amosov-Holevo-Werner(see Probl. Inform. Transm., vol.36, p.305-313, 2000) p-norm conjecture for this product channel for all p/spl ges/1, and deduce from this the additivity of the minimal entropy and of the Holevo quantity /spl chi//sup */.     

Ultrastructural basis for the transition of cell death mode from apoptosis to necrosis in menadione-treated osteosarcoma 143B cells

Time-dependent ultrastructural changes of menadione-treated human osteosarcoma 143B cells were correlated with those in their stainability to Annexin V and propidium iodide (PI). Populations of both apoptotic (Annexin V(+)/PI(-)) and necrotic (Annexin V(+)/PI(+)) cells, judged by flow cytometry, began to increase at 2 h after menadione treatment. The former reached a maximum at 6 h followed by abrupt decreases thereafter, while the latter continued to increase. Electron microscopically, cells obtained at 6 h after the menadione treatment consisted of mixed populations of cells with typical apoptotic features and those with a mixture of apoptotic and necrotic features, while cells obtained at 8-24 h consisted exclusively of cells with a mixture of apoptotic and necrotic features. Thus, necrotic cells, as judged by flow cytometry, were in a transitional state of cell death mode from apoptosis to necrosis and are thus designated as 'intermediate cells'. Lack of apoptotic bodies, judged by flow cytometric analysis on sub-G1 nuclei and by electron microscopy in menadione-treated cells, suggested that the transition of cell death mode from apoptosis to necrosis occurred before the apoptotic processes were completed. Effects of N-acetylcysteine and Z-VAD-fmk on menadione-induced ultrastructural changes were also studied.     

Two types of the enlargement of mitochondria related to apoptosis: simple swelling and the formation of megamitochondria

Our recent finding that free radical-induced formation of megamitochondria (MG) is followed by apoptosis has prompted us to investigate the correlation between the MG formation and the swelling of mitochondria which is considered to play a key role in early stages of apoptotic processes of the cell. Mitochondria of rat hepatocytes or RL-34 cells and those isolated from rat livers became enlarged up to three times in their diameters when they were exposed to a hypotonic medium. MG induced in the liver of rats placed on a 1% hydrazine-diet for 4-5 days or those induced in the liver of mice placed on a 2% chloramphenicol (CP)-diet for 9-10 days were endowed with a dense matrix whereas those fed with the toxic diets for longer periods of time became enlarged further and their matrix became extremely pale indicating that MG in the latter animals became swollen secondarily. The membrane potential, the content of cytochrome c and the rate of the generation of reactive oxygen species (ROS) of MG in the former animals were almost unchanged compared to those of mitochondria in control animals whereas those of MG in the latter animals became distinctly decreased. These results may suggest that free radical-induced MG possibly cause apoptosis via their secondary swelling.     

Kullback-Leibler approximation of spectral density functions

We introduce a Kullback-Leibler (1968) -type distance between spectral density functions of stationary stochastic processes and solve the problem of optimal approximation of a given spectral density /spl Psi/ by one that is consistent with prescribed second-order statistics. In general, such statistics are expressed as the state covariance of a linear filter driven by a stochastic process whose spectral density is sought. In this context, we show (i) that there is a unique spectral density /spl Phi/ which minimizes this Kullback-Leibler distance, (ii) that this optimal approximate is of the form /spl Psi//Q where the "correction term" Q is a rational spectral density function, and (iii) that the coefficients of Q can be obtained numerically by solving a suitable convex optimization problem. In the special case where /spl Psi/ = 1, the convex functional becomes quadratic and the solution is then specified by linear equations.     

Role of mitochondria in the switch mechanism of the cell death mode from apoptosis to necrosis--studies on rho0 cells

Detailed mechanisms of the switch of the cell death mode from apoptosis to necrosis remain to be solved, although the intracellular level of ATP and that of free radicals have been postulated to be the major factors involved in the mechanisms. In the present study menadione (MEN)-induced cell injury processes were studied using rho0 cells derived from human osteosarcoma 143B cells and parental rho+ cells co-treated with inhibitors of electron transfer chain of mitochondria or oligomycin, an inhibitor of ATP synthesis. Treatment of rho+ cells with 100 microM MEN induced apoptosis, which reached the maximum at 6 h, and was followed by an abrupt decrease thereafter, while necrotic cells (NC) increased continuously when they were judged by Annexin V and PI double staining. On the other hand, MEN induced apoptotic and necrotic changes much faster in rho0 cells compared to rho+ cells. The frequency to find apoptotic cells (AP) in the former cells was distinctly smaller than that to find NC judged by Annexin V and PI double staining. Electron microscopically, a major population of rho0 cells treated with MEN for 6 h consisted of intermediate cells, and a small number of AP co-existed. At 9 h of the treatment intermediate cells were exclusively seen, and AP were hardly detected. When parental rho+ cells were treated with MEN in the presence of oligomycin or oligomycin plus antimycin A both apoptotic and necrotic changes of the cells were distinctly accelerated. The intracellular level of superoxide in rho0 cells continuously increased after the MEN treatment, whereas that of ATP remained distinctly low before and after the MEN treatment compared to that in rho+ cells. These data suggest that the intracellular level of superoxide may be a key factor controlling the switch from apoptosis to necrosis.     

Modeling good conductors using the finite-difference, time-domaintechnique

Finite-difference, time-domain (FDTD) is based upon the assumption that field behavior between sample points (i.e., cell nodes) is linear; for propagation in lossless or low-loss materials, the assumption of linearity will be valid as long as the number of cells per wavelength is kept above some minimum value. For good conductors, where the wavelength decreases many orders of magnitude from its free-space size, and the fields are decaying exponentially, it becomes impractical to shrink the cell size so as to maintain linearity between cells. When the number of cells per wavelength criterion is violated at a boundary, FDTD will not yield correct estimates of reflection from, or transmission into, that boundary. The work presented details and provides validation for two approaches that can be used to achieve realistic results when modeling good conductors with FDTD using practical cell sizes. These approaches do not require modifications to the FDTD algorithms, and do not affect program execution times. Achieving accurate loss estimates will be of particular interest to those modeling resonant structures using FDTD     

Actin ring formation around the cell nucleus of long-neck yeast

The unique long-neck yeast Fellomyces fuzhouensis has F-actin cables and cortical patches. Here, we describe a new F-actin structure present in fungi, a perinuclear F-actin collar ring around the cell nucleus. This F-actin structure can be visualized by fluorescent microscopic imaging of rhodamine-phalloidin-stained F-actin in cells treated with the mitotic drug isopropyl N-(3-chlorophenyl) carbamate or the microtubule inhibitor thiabendazol or when cells were grown in cut dried radish medium or yeast extract pepton dextrose (YEPD) medium. In contrast, these structures were absent in cells treated with Latrunculin A. The hypothetical functions of the F-actin ring are discussed.     

Changes in physicochemical properties of microtubules lead to the formation of a single spherical structure of mitochondrial assembly enveloping nuclear chromatins

Treatment of 143B cells with microtubule-active drugs (MADs) including taxol, nocodazole and colchicine induced distinct structural changes, such as rounding of the cells with perinuclear clustering of mitochondria, when the cells were treated for up to 10 h. When the incubation time with MADs was longer than 10 h, multinuclear cells appeared, and their population increased with time. In this study perinuclear clustering of mitochondria i.e. mitochondria encircling the aggregated chromatin of the nucleus that had lost the nuclear membrane was detected. This observation was distinct from that reported in the literature. Mitochondria were aligned in a few lines; the occurrence of mitochondria in even a single line is an extreme case, resulting in one plane of section for electron microscopy. Three-dimensional reconstructions of confocal microscopic images of mitochondria revealed that they were assembled as a spherical structure. The majority of the cells with perinuclear clustering of mitochondria remained intact for up to 24 h. Mitochondria were observed to be clustered around the nucleus in the orthodox configuration or in some cases they were moderately condensed, as observed electron microscopically. Annexin V and PI double staining of cells showed that more than 90% of cells were viable. In the case of treatment with taxol, membrane potential of mitochondria per cell was well maintained although it was moderately lowered in the case of treatment with nocodazole. Taking into consideration the previous data reported from our laboratory, the present results may assist in elucidation of the behaviour of mitochondria during the dividing processes of mammalian cells, which is yet to be clarified.     

Quantitative analyses of topography and elasticity of living and fixed astrocytes

The topography and elasticity of living and fixed astrocytes cultured from the rat cerebra were studied quantitatively by atomic force microscopy (AFM). Ridge-like structures reflecting F-actin beneath the cell membrane were prominent in the contact-mode images of living astrocytes. Many of these ridges became unclear after fixation (2% glutaraldehyde). In addition, the ridge-like structures were invisible in the topography of living cells observed at zero-loading force in the force mapping mode, which is considered to show the real cell surface not pressed down by an AFM tip. The topography of fixed cells observed both in the contact mode and at zero-loading force in the force mapping mode was similar to that of living cells observed at zero-loading force in the force mapping mode, although some deformed areas were detected in the fixed cells. The elasticity map images of living astrocytes showed that the cell membrane above the nucleus was softer (2-3 kPa) than the surroundings, and that the cell membrane above F-actin was stiffer (10-20 kPa) than the surroundings. In the elasticity map images of fixed astrocytes, on the other hand, the elasticity of the cells was found to be relatively uniform (200-700 kPa) irrespective of the inner structures of cells. These results show that images observed by AFM should be carefully examined in consideration of the force introduced to specimens and the elasticity of specimens to find out the real surface topography.     

Novel ultrahigh-density flash memory with a stacked-surrounding gate transistor (S-SGT) structured cell

In order to overcome the limitation of cell area of 4F/sup 2/ per bit in conventional NAND flash memory cells, stacked-surrounding gate transistor (S-SGT) structured cell is proposed. This newly structured cell achieves a cell area of 4F/sup 2//N per bit, where N is the number of stacked memory cells in one silicon pillar, without using multibit per memory cell technology. The S-SGT structured cell consisting of two stacked memory cells in one silicon pillar achieves a cell area per bit of less than 50% of the smallest reported NAND structured cell. The novel S-SGT structured cells are fabricated by vertical self-aligned processes using a 0.2 /spl mu/m design rule. The S-SGT structured cell can be programmed and erased by uniform injection and uniform emission of Fowler-Nordheim (F-N) tunneling electrons over the whole channel area of the memory cell, respectively, which is the same program and erase mechanism as in conventional NAND structured cell. This high performance S-SGT structured cell is applicable to high-density nonvolatile memories for 16 G/64 G bit Flash memories and beyond.     

Performance enhancement of offset gated polysilicon thin-film transistors

Simple offset gated n-channel polysilicon thin film transistors (TFTs) of channel length L=10 /spl mu/m were investigated in relation to the intrinsic offset length /spl Delta/L and the polysilicon quality. For /spl Delta/L/spl les/1 /spl mu/m, the device parameters such as threshold voltage, subthreshold slope and field effect mobility are improved, while the leakage current remains unchanged. In TFTs with /spl Delta/L>1 /spl mu/m, the leakage current decreases with increasing the offset length. When the polysilicon layer is of high quality (large grain size and low intra-grain defect density), the leakage current is completely suppressed without sacrificing the on-current in TFT's with offset length of 2 /spl mu/m.     

Quantitative three-dimensional structural analysis of Exophiala dermatitidis yeast cells by freeze-substitution and serial ultrathin sectioning

The morphologies, numbers, sizes and volumes of all organelles and cell components identified on ultrathin sections of aerobically grown exponential phase yeast cells of Exophiala dermatitidis in G1 phase were examined by freeze-substitution fixation and serial ultrathin sectioning. The cell wall consisted of three layers and occupied approximately 22% of the cell volume. The nucleus was approximately 1.8 microm in diameter and occupied approximately 7% of the cell volume. There was only one nucleolus in the nucleus and it occupied approximately 16% of the nuclear volume. There were 17-52 mitochondria per cell, occupying 7-12% of the cell volume. Five to ten endoplasmic reticula were present per cell; these occupied only 0.2% of the cell volume and did not form a network. There were 1-4 vacuoles per cell and they occupied 4-10% of the cell volume. Storage material was round and electron transparent and occupied 4-11% of the cell volume. The cytosol occupied 43-53% of the cell volume. The Golgi apparatus, spindle pole body, autophagosomes, multivesicular bodies, lipid bodies, microtubules and microfilaments occupied approximately 1% of the cell volume in total. About 200,000 ribosome particles, 1000 glycogen granules and several tens of microtubules (average length 0.78 microm) were present per yeast cell. The membranes of this yeast could be classified into three groups by their appearance and thickness. This is the first report, to our knowledge, that analysed all the components in the yeast cell quantitatively and in three dimensions, and provides fundamental information for understanding various aspects of cell biology.     

用JSP构建动态网站

JSP技术是当前较为热门的Web开发技术。本文详细介绍了JSP的基本工作原理及利用JSP构建动态网站的步骤，就JSP的关键技术如编译指令、JavaBean、数据库与JDBC技术的实现及应用进行了扼要的阐述。最后就当前最热门的动态网站开发工具JSP和ASP从技术上进行了分析和比较，肯定了JSP在构建动态网站中的优势。     

Optimization of picosecond laser structuring for the monolithic serial interconnection of CIS solar cells

We report on the optimization of selective picosecond laser structuring for the monolithic serial interconnection of (Cu(In,Ga)(S,Se)₂) CIS thin film solar cells. We introduce a quantitative value to compare the energy efficiency of the different investigated laser processes, the specific ablation energy, which indicates the required energy to remove a certain volume of the specific material. We have examined the structuring efficiencies for induced laser ablation processes for a modification of the beam profile (elliptical and flat‐top beam shaping) and for the application of different laser wavelengths (1064 and 532 nm). Application of induced laser processes (often referred as “lift‐off”) decreases the specific ablation energy dramatically by nearly one order of magnitude. Modifications of the beam profile such as elliptical and flat‐top beam shaping are nearly halving the energy per ablated volume relative to a circular beam. The application of a laser wavelength 532 nm decreases the specific ablation energy compared with 1064 nm significantly for processes involving the CIS layer. We finally demonstrate that with a picosecond laser power of only 2 W, the molybdenum back contact (P1, glass side) and the ZnO front contact (P3, ZnO on CIS) can be structured with a process speed of up to 4 m/s. About 2 µm thick CIS layer (P2) is structured by standard direct laser ablation at higher energy densities with 200 mm/s. Copyright © 2012 John Wiley & Sons, Ltd.     

A Biomimetic,Copolymeric Membrane for Cell-Stretch Experiments with Pulmonary Epithelial Cells at the Air-Liquid Interface

Chronic respiratory diseases are among the leading causes of death worldwide, but only symptomatic therapies are available for terminal illness. This in part reflects a lack of biomimetic in vitro models that can imitate the complex environment and physiology of the lung. Here, a copolymeric membrane consisting of poly(ε-)caprolactone and gelatin with tunable properties, resembling the main characteristics of the alveolar basement membrane is introduced. The thin bioinspired membrane (≤5 μm) is stretchable (up to 25% linear strain) with appropriate surface wettability and porosity for culturing lung epithelial cells under air–liquid interface conditions. The unique biphasic concept of this membrane provides optimum characteristics for initial cell growth (phase I) and then switch to biomimetic properties for cyclic cell-stretch experiments (phase II). It is showed that physiologic cyclic mechanical stretch improves formation of F-actin cytoskeleton filaments and tight junctions while non-physiologic over-stretch induces cell apoptosis, activates inflammatory response (IL-8), and impairs epithelial barrier integrity. It is also demonstrated that cyclic physiologic stretch can enhance the cellular uptake of nanoparticles. Since this membrane offers considerable advantages over currently used membranes, it may lead the way to more biomimetic in vitro models of the lung for translation of in vitro response studies into clinical outcome.     

A New View of Microcrystalline Silicon: The Role of Plasma Processing in Achieving a Dense and Stable Absorber Material for Photovoltaic Applications

To further lower production costs and increase conversion efficiency of thin‐film silicon solar modules, challenges are the deposition of high‐quality microcrystalline silicon (μc‐Si:H) at an increased rate and on textured substrates that guarantee efficient light trapping. A qualitative model that explains how plasma processes act on the properties of μc‐Si:H and on the related solar cell performance is presented, evidencing the growth of two different material phases. The first phase, which gives signature for bulk defect density, can be obtained at high quality over a wide range of plasma process parameters and dominates cell performance on flat substrates. The second phase, which consists of nanoporous 2D regions, typically appears when the material is grown on substrates with inappropriate roughness, and alters or even dominates the electrical performance of the device. The formation of this second material phase is shown to be highly sensitive to deposition conditions and substrate geometry, especially at high deposition rates. This porous material phase is more prone to the incorporation of contaminants present in the plasma during film deposition and is reported to lead to solar cells with instabilities with respect to humidity exposure and post‐deposition oxidation. It is demonstrated how defective zones influence can be mitigated by the choice of suitable plasma processes and silicon sub‐oxide doped layers, for reaching high efficiency stable thin film silicon solar cells.     

全反式维甲酸对卵巢上皮性癌荷瘤鼠干预后肿瘤细胞的超微结构变化

探讨全反式维甲酸(all-trans retinoic acid,ATRA)对裸鼠卵巢上皮性癌细胞(CAOV3)荷瘤动物模型干预后肿瘤细胞超微结构的变化及意义。每只荷瘤裸鼠经胃管针给药ATRA剂量为2mg/kg 2d×4周,取新鲜肿瘤组织进行电镜制样观察。结果显示CAOV3荷瘤裸鼠经ATRA干预后,肿瘤细胞出现细胞表面微绒毛明显增多,细胞间常见桥粒和紧密连接,胞浆内粗面内质网、线粒体和糖原颗粒增加,还有发育良好的高尔基体,细胞核异染色质增加,常染色质减少,偶见被吞噬的凋亡细胞。上述超微结构变化提示ATRA可诱导和促进CAOV3细胞分化,抑制肿瘤生长。     

FM-laser operation of the Nd:YAG laser

The FM-laser or frequency-sweeping mode of laser oscillation has been demonstrated in a Nd :YAG 1.06-μ laser with an intracavity LiNbO3phase modulator. The experimental results are in excellent agreement with the theoretical expressionDelta= (DeltaOmega/Deltanu) (delta/pi)where δ= peak single-pass phase retardation in the modulator,DeltaOmega= axial mode spacing,Deltanu=modulator detuning, and Δ=resulting FM index of the laser output. Modulation indices as large asDelta approx 230rad have been obtained, in which case the instantaneous laser frequency is sweeping over a full spectral range of2Delta cdot f_{m} approx 120GHz (≈ 4 cm^-1) at a repetition frequencyf_{m} approx 260MHz, with a time-bandwidth product per periodapprox 2Delta approx 460. The coherently mode-locked spectral bandwidth thus obtained in the FM-laser case is very much wider than can be achieved in the pulsed mode-locked case with the same Nd:YAG laser. Some possible ways of using this broad-band coherent FM spectrum are suggested.     

Storage array and sense/refresh circuit for single-transistor memory cells

For the cell layout in silicon-gate technology a storage capacitor is proposed that uses a field-induced nonequilibrium inversion layer as an electrode. As a sensitive refresh amplifier a gated flip-flop that can be used for one digit line at each of its two input nodes is presented. Different cells and refresh circuits have been realized in silicon-gate technologies. Cells with an area of 1600 /spl mu/m/SUP 2/(2.6 mil/SUP 2/) have been successfully operated with a READ/WRITE cycle time of 350 ns (storage capacitance 0.134 pF, digit line capacitance 0.32 pF for 64 cells per line or 128 cells per amplifier).     

Hierarchical Spiky Microstraws‐Integrated Microfluidic Device for Efficient Capture and In Situ Manipulation of Cancer Cells

Techniques for capturing circulating tumor cells (CTCs) play an important role in cancer diagnosis. Recently, various 3D micro/nanostructures have been applied for effective CTC detection, yet in situ manipulation of the captured cancer cells on micro/nano‐structural substrates is rarely achieved. In this work, a hierarchical spiky microstraw array (HS‐MSA)‐integrated microfluidic device is demonstrated that possessed dual functions of cancer cell capture and in situ chemical manipulations of the captured cells. The 3D micro/nanostructure of HS‐MSA could capture cancer cells with high efficiency (≈84%) and strong specificity. Based on the HS‐MSA‐integrated microfluidic device, extracellular drug delivery to the captured cancer cells is achieved in situ with excellent spatial, dose, and temporal controls. In addition, a drug‐screening assay on the captured cancer cells is implemented to investigate the cell apoptosis behavior under the microstraw‐mediated delivery of staurosporine (STS). This microfluidic system not only presents tremendous potential for CTCs detection technology, but also opens up new opportunities for high‐throughput drug screening on cancer cells and understanding the cellular activity.