Emission and Transmission Properties of a Doubly Resonant 3D Nanodisk Yagi–Uda Antenna for Wireless Optical Communications

In this paper, a novel doubly resonant three-dimensional (3D) nanodisk Yagi–Uda antenna, conceived for realizing wireless optical links within electronic circuits, is proposed. The prominent emitting properties of this nanoantenna have been deeply investigated both in the near and far field through a useful comparison with a more traditional 3D nanorod Yagi–Uda antenna. The behavior of the nanodisk antenna, both configured as a single nanoantenna and arranged in planar arrays, have been illustrated, emphasizing its improved performances with relation to crucial aspects as directional features, wavelength bands of operation, frequency tuning, and polarization influence on radiation. In particular, the single nanodisk antenna has been accurately designed to enhance the transmission feature in the near field at the wavelengths λ?=?1.3 and λ?=?1.55 μm. Also, the emission pattern of the array of nanodisk antennas has been properly tailored to ensure high peaks of directivity and narrow beam width in those ranges. Hence, efficient unidirectional angle patterns have been shaped for any operation wavelength and dimensions of the array, reaching extremely effective outcomes for a 3?×?3 array, which exhibits a maximum of directivity of 19 and 17.6 and ?3 dB points at 18° and 21° for λ?=?1.3 and λ?=?1.55 μm, respectively.     

Beam Steering Plasma Reflectarray/Transmitarray Antennas

The aim of this paper is to design and analyze plasma reflectarray/transmitarray antennas which include investigation of performance parameters for these antennas in free space. The unit cell element for both arrays consists of a cubic glass box with fixed dimensions filled by argon gas. The plasma frequency of the argon gas is varied by changing the applied voltage at both ends of the glass box. This allows steering the reflected/transmitted wave to a certain direction. Full-wave simulations using the finite element method (FEM) and finite integral technique (FIT) are used to optimize and analyze different plasma reflectarray and plasma transmitarray antennas. The plasma reflectarray antenna is composed of 13?×?13 elements and covered an area of 208?×?208 mm². A circular horn is used to feed the antenna at a distance of 20.8 cm (focal-to-diameter ratio (F/D)?=?1). The reflectarray is designed at f?=?12 GHz. The radiation patterns of the plasma reflectarray for scanning angles of 10° to 70° angles are illustrated. For larger scanning angles, significant sidelobe levels are produced. The maximum value of beam scanning gain patterns is reduced. The half-power beamwidth (HPBW) is increased. The plasma transmitarray is composed of 9?×?9 cell elements and covered an area of 72?×?72 mm². The feed is a linearly polarized circular horn. The F/D ratio is set to 1. The transmitarray is operating at f?=?15 GHz. The radiation patterns of the plasma transmitarray for scanning angles of ?40° to +40° are demonstrated. Significant sidelobe levels are produced at large scanning angles.     

基于小波变换的混合二维ECG数据压缩方法

提出了一种新的基于小波变换的混合二维心电(electrocardiogram,ECG)数据压缩方法。基于ECG数据的两种相关性,该方法首先将一维ECG信号转化为二维信号序列。然后对二维序列进行了小波变换,并利用改进的编码方法对变换后的系数进行了压缩编码:即先根据不同系数子带的各自特点和系数子带之间的相似性,改进了等级树集合分裂(setpartitioninghierarchicaltrees,SPIHT)算法和矢量量化(vectorquantization,VQ)算法;再利用改进后的SPIHT与VQ相混合的算法对小波变换后的系数进行了编码。利用所提算法与已有具有代表性的基于小波变换的压缩算法和其他二维ECG信号的压缩算法,对MIT/BIH数据库中的心律不齐数据进行了对比压缩实验。结果表明:所提算法适用于各种波形特征的ECG信号,并且在保证压缩质量的前提下,可以获得较大的压缩比。     

Multilayer Hybrid Plasmonic Nano Patch Antenna

This is the first report of a hybrid plasmonic nano patch antenna having metal insulator metal (HMIM) multilayer configuration. It is designed in a footprint area of 1.7 × 1.175 μm² to resonate at 1.55 μm wavelength. The proposed antenna is inset fed by an HMIM plasmonic waveguide for achieving proper impedance matching. It is observed, through electromagnetic numerical simulation, that the proposed plasmonic nano patch antenna emits a directional beam with a bandwidth, gain, and efficiency of 0.194 μm, 8.3 dB, and 96% respectively, which are significantly higher than previously reported designs. Since inset-fed antennas are suitable for developing high-gain antenna array, hence further, we examined antenna performance by designing antenna array. The proposed antenna is practically realizable and can be fabricated using standard semiconductor fabrication process. Moreover, it could be used for numerous chip scale applications such as wireless interconnects energy harvesting, photoemission, photo detection, scattering, heat transfer, spectroscopy, and optical sensing.

     

Metamaterial-Embedded Low SAR PIFA for Cellular Phone

A metamaterial-embedded planar inverted-F antenna (PIFA) is proposed in this study for cellular phone applications. A dual-band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of a conventional PIFA is modified using a planar one-dimensional metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The performance of the developed antenna was measured in an anechoic chamber. The specific absorption rate (SAR) values are calculated considering two different holding positions: cheek and tilt. The SAR values are measured using COMOSAR measurement system. Good agreement is observed between the simulated and measured data. The results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances.     

Effects of 3-D clino-rotation on gene expression in human fibroblast cells

Continuous variation in the direction of the gravity vector leads to various cellular responses including modulation of gene expression. Complementary DNA (cDNA) array analyses are available to observe the variation of gene expression under different conditions. In this study, expression levels of 588 representative genes were compared using the Atlas human cDNA expression array in human fibroblast cells with and without 3-dimensional (3-D) clinostat. Five upregulated and 8 downregulated genes were detected. Among these genes, upregulation of XRCC1, and downregulation of ERB-B2 and p21(Cip1/Waf1) were confirmed by RT-PCR. These results suggested that the gene expression levels of XRCC1, ERB-B2 and p21(Cip1/Waf1) were modulated by vector-averaged microgravity induced by 3-D clinostat in human fibroblast cells. Our findings may be a basis for the biological study of 3-D culture systems.     

Effect of SAR on human head modeling inside cylindrical enclosures

This study intends to discuss enclosed a realistic approach to determine and analyze the effects of radio frequency on human exposure inside a cylindrical enclosure. A scenario in which a mobile phone with inverted-F antenna (IFA) operating in the Global System for Mobile Communication (GSM) band (900 MHz) is used inside a cylindrical enclosure. Metallic enclosures are known to have resonance and reflection effects, thereby increasing electric field strength and hence resulting in a change of the human exposure to electromagnetic absorptions. So, this study examines and compares the levels of absorption in terms of specific absorption rate (SAR) values under various conditions. In this study, a human phantom with dielectric properties is designed and its interaction is studied with IFA inside fully enclosed cylindrical enclosures. The results show that SAR values are increased inside cylindrical enclosures compared with those in free space. The method of computation uses method of moments. Simulations are done in FEKO software.     

Computer-aided microtomography with true 3-D display in electron microscopy

A novel research system has been designed to permit three-dimensional (3-D) viewing of high resolution image data from transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The system consists of front-end primary data acquisition devices, such as TEM and SEM machines, which are equipped with computer-controlled specimen tilt stages. The output from these machines is in analogue form, where a video camera attached to the TEM provides the sequential analogue image output while the SEM direct video output is utilized. A 10 MHz digitizer transforms the video image to a digital array of 512 X 512 pixel units of 8 bits deep-stored in a frame buffer. Digital images from multiple projections are reconstructed into 3-D image boxes in a dedicated computer. Attached to the computer is a powerful true 3-D display device which has hardware for graphic manipulations including tilt and rotate on any axis and for probing the image with a 3-D cursor. Data editing and automatic contouring functions are used to enhance areas of interest, and specialized software is available for measurement of numbers, distances, areas, and volumes. With proper archiving of reconstructed image sequences, a dynamic 3-D presentation is possible. The microtomography system is highly versatile and can process image data on-line or from remote sites from which data records would typically be transported on computer tape, video tape, or floppy disk.     

Real-time spectrum estimation–based dual-channel speech-enhancement algorithm for cochlear implant

Background

Improvement of the cochlear implant (CI) front-end signal acquisition is needed to increase speech recognition in noisy environments. To suppress the directional noise, we introduce a speech-enhancement algorithm based on microphone array beamforming and spectral estimation. The experimental results indicate that this method is robust to directional mobile noise and strongly enhances the desired speech, thereby improving the performance of CI devices in a noisy environment.

Methods

The spectrum estimation and the array beamforming methods were combined to suppress the ambient noise. The directivity coefficient was estimated in the noise-only intervals, and was updated to fit for the mobile noise.

Results

The proposed algorithm was realized in the CI speech strategy. For actual parameters, we use Maxflat filter to obtain fractional sampling points and cepstrum method to differentiate the desired speech frame and the noise frame. The broadband adjustment coefficients were added to compensate the energy loss in the low frequency band.

Discussions

The approximation of the directivity coefficient is tested and the errors are discussed. We also analyze the algorithm constraint for noise estimation and distortion in CI processing. The performance of the proposed algorithm is analyzed and further be compared with other prevalent methods.

Conclusions

The hardware platform was constructed for the experiments. The speech-enhancement results showed that our algorithm can suppresses the non-stationary noise with high SNR. Excellent performance of the proposed algorithm was obtained in the speech enhancement experiments and mobile testing. And signal distortion results indicate that this algorithm is robust with high SNR improvement and low speech distortion.     

Electronic Beam Switching of Circularly Polarized Plasma Magneto-Electric Dipole Array with Multiple Beams

In this paper, different array arrangements based on magneto-electric (ME) dipole antenna with wideband circular polarization (CP) characteristics are designed and investigated. Planar, triangular prism, square prism, and hexagonal prism array arrangements are considered. Each prism face has a sub-array comprises 2 × 2 ME-dipole elements. Each sub-array has wide impedance matching of 73.7%, a maximum gain of 16.6 dBi, and CP bandwidth of 78.2%. It employs the plasma frequency of the ME-dipole antenna to control its radiation characteristics. Frequency-independent lumped element equivalent circuit is constructed for a single antenna element. It is used to represent the antenna input impedance at different plasma electron densities with fixed physical structure. The proposed equivalent circuit comprises a single series section used for matching enhancement with feeder circuit, and three parallel tuned circuits corresponding to the three resonance frequencies in the input impedance. The best values of the equivalent circuit elements are computed using the particle swarm optimization (PSO) technique. Different array arrangements, planar, triangular, square, and hexagonal prism are designed to create single or multiple beams in different directions. An electronic beam switching is achieved by tuning in the plasma inside the ME-dipole in the desired direction. The radiation characteristics are analyzed and investigated using the finite integration technique (FIT).

     

Array based capillary IEF with a whole column image of laser-induced fluorescence in coupling to capillary RPLC as a comprehensive 2-D separation system for proteome analysis

Based on array CIEF (ACIEF) and a novel whole column imaging detection (WCID), a comprehensive 2-D system with laser-induced fluorescence was developed for protein mapping. By coupling capillary RPLC (CRPLC) as the first dimension and ACIEF as the second dimension, a high-throughput and high-resolution proteomic expression profiling was obtained. An array of up to 60 capillaries was assembled, with electrical connections made through filling small breaks, created on each capillary at positions of buffer reservoirs, with a porous polymer. A whole column image system with laser-induced fluorescence (LIF) was devised. Spot excitation was performed with a laser converted to produce linear light, and a CCD camera was employed to take images of the protein fluorescence during line laser scanning of the capillary array. Quantitative detection of thousands of focusing protein bands in the capillary array was achieved. Details on the capillary array fabrication and scanning LIF detection system devices are discussed. The efficiency of this CRPLC-ACIEF-LIF-WCID system was further demonstrated using samples of soluble proteins extracted from liver cancer tissue. The overall peak capacity was estimated to be around 18 000 in an analysis time of less than 3 h. The reproducibility of consecutive runs and different columns were assessed as having an RSD of 1.5% and 2.2% in focusing positions, respectively.     

Investigation of a New Electrode Array Technology for a Central Auditory Prosthesis

Ongoing clinical studies on patients recently implanted with the auditory midbrain implant (AMI) into the inferior colliculus (IC) for hearing restoration have shown that these patients do not achieve performance levels comparable to cochlear implant patients. The AMI consists of a single-shank array (20 electrodes) for stimulation along the tonotopic axis of the IC. Recent findings suggest that one major limitation in AMI performance is the inability to sufficiently activate neurons across the three-dimensional (3-D) IC. Unfortunately, there are no currently available 3-D array technologies that can be used for clinical applications. More recently, there has been a new initiative by the European Commission to fund and develop 3-D chronic electrode arrays for science and clinical applications through the NeuroProbes project that can overcome the bulkiness and limited 3-D configurations of currently available array technologies. As part of the NeuroProbes initiative, we investigated whether their new array technology could be potentially used for future AMI patients. Since the NeuroProbes technology had not yet been tested for electrical stimulation in an in vivo animal preparation, we performed experiments in ketamine-anesthetized guinea pigs in which we inserted and stimulated a NeuroProbes array within the IC and recorded the corresponding neural activation within the auditory cortex. We used 2-D arrays for this initial feasibility study since they were already available and were sufficient to access the IC and also demonstrate effective activation of the central auditory system. Based on these encouraging results and the ability to develop customized 3-D arrays with the NeuroProbes technology, we can further investigate different stimulation patterns across the ICC to improve AMI performance.     

黄胸蓟马触角感器的形态和分布

[目的]本研究旨在明确黄胸蓟马Thrips hawaiiensis各个发育阶段触角感器类型、形态和分布.[方法]运用扫描电镜技术观察黄胸蓟马雌雄成虫、若虫、预蛹、蛹触角的形态结构以及触角上感器类型、形态和分布.[结果]黄胸蓟马成虫触角由柄节、梗节和鞭节3个部分组成,其中长的鞭节分为5个鞭小节(Ⅰ-Ⅴ).雌成虫触角平均长...     

Compensated Row-Column Ultrasound Imaging System Using Fisher Tippett Multilayered Conditional Random Field Model

3-D ultrasound imaging offers unique opportunities in the field of non destructive testing that cannot be easily found in A-mode and B-mode images. To acquire a 3-D ultrasound image without a mechanically moving transducer, a 2-D array can be used. The row column technique is preferred over a fully addressed 2-D array as it requires a significantly lower number of interconnections. Recent advances in 3-D row-column ultrasound imaging systems were largely focused on sensor design. However, these imaging systems face three intrinsic challenges that cannot be addressed by improving sensor design alone: speckle noise, sparsity of data in the imaged volume, and the spatially dependent point spread function of the imaging system. In this paper, we propose a compensated row-column ultrasound image reconstruction system using Fisher-Tippett multilayered conditional random field model. Tests carried out on both simulated and real row-column ultrasound images show the effectiveness of our proposed system as opposed to other published systems. Visual assessment of the results show our proposed system’s potential at preserving detail and reducing speckle. Quantitative analysis shows that our proposed system outperforms previously published systems when evaluated with metrics such as Peak Signal to Noise Ratio, Coefficient of Correlation, and Effective Number of Looks. These results show the potential of our proposed system as an effective tool for enhancing 3-D row-column imaging.     

A new triple crossover triangle (TXT) motif for DNA self-assembly

A new triple crossover triangle (TXT) motif was conceived on the basis of the DNA triple crossover (TX) motif. The new motif is rigid and triangular prism-shaped, out of which 1-D, 2-D, and 3-D DNA structures can be assembled. The 1-D TXT array was self-assembled and was observed by the TEM with negative staining by uranyl acetate. The architectural schemes for 2-D and 3-D structures are presented.     

Biologically inspired coupled antenna beampattern design

We propose to design a small-size transmission-coupled antenna array, and corresponding radiation pattern, having high performance inspired by the female Ormia ochracea's coupled ears. For reproduction purposes, the female Ormia is able to locate male crickets' call accurately despite the small distance between its ears compared with the incoming wavelength. This phenomenon has been explained by the mechanical coupling between the Ormia's ears, which has been modeled by a pair of differential equations. In this paper, we first solve these differential equations governing the Ormia ochracea's ear response, and convert the response to the pre-specified radio frequencies. We then apply the converted response of the biological coupling in the array factor of a uniform linear array composed of finite-length dipole antennas, and also include the undesired electromagnetic coupling due to the proximity of the elements. Moreover, we propose an algorithm to optimally choose the biologically inspired coupling for maximum array performance. In our numerical examples, we compute the radiation intensity of the designed system for binomial and uniform ordinary end-fire arrays, and demonstrate the improvement in the half-power beamwidth, sidelobe suppression and directivity of the radiation pattern due to the biologically inspired coupling.     

A study on Cormic Index among semi-urban Bengalee Boys of West Bengal, India

Since stature is an additive measurement, it would be useful to examine the pattern of its constituent segments in terms of sitting height and subischial leg length for the evaluation and insight of various growth related issues as well. The aim of the present study was to understand the growth patterns with respect to height (HT), sitting height (SH), subischial leg length (SLL), Cormic Index (CRI) and their relationship with age. The present cross-sectional study includes 162 Bengalee boys aged 6-12 years. Age effect displayed significant positive correlation with HT (r = 0.734), SLL (r = 0.731) and SH (r = 0.637). However, CRI revealed significant negative correlation (r = -0.433) with age. This may be due to the fact that in these ages tempo of growth in SLL was higher than SH. Age-wise correlation between SH and SLL changes dramatically and varies from 0.474 to 0.750 due to the variation in the tempo of growth.     

A packed Cytodex microbead array for three-dimensional cell-based biosensing

A packed Cytodex 3 microbead array was fabricated as a simple three-dimensional (3-D) cell-based biosensing format. Resting membrane potentials and voltage-gated calcium channel (VGCC) function of SH-SY5Y human neuroblastoma cells cultured on the microbead array versus collagen-coated flat (2-D) substrates were evaluated by confocal microscopy with a potentiometric dye, tetramethylrhodamine methyl ester, and a calcium fluorescent indicator, Calcium Green-1. SH-SY5Y cells, differentiated with 1mM dibutyryl cAMP and 2.5 microM 5-bromodeoxyuridine, showed significant resting membrane potential establishment on the topographical scaffolds in a period of 13 days into differentiation, in contrast to the previously reported insignificant resting membrane potential establishment of the same cells within collagen hydrogels. On days 2, 8 and 13 into differentiation, cells on collagen-coated flat substrates developed resting membrane potentials of -6.0+/-19.5 mV (n=198), -30.5+/-19.9 mV (n=191) and -21.7+/-18.9 mV (n=308), in contrast to values for cells on 3-D scaffolds of -25.8+/-14.7 mV (n=112), -37.6+/-13.1 mV (n=120) and -28.7+/-12.2 mV (n=158), respectively. The development of VGCC function, as measured by percentage of cells responsive to 50 mM high K(+) depolarization, was significantly slower for cells on 3-D scaffolds (20.0% on day 13 into differentiation) than for cells on 2-D substrates (30.7% on day 8 into differentiation). The exaggerated 2-D cell calcium dynamics, in comparison with those of 3-D cells, is consistent with previous 2-D/3-D comparative studies. This study established the rationale and feasibility of the microbead array format for 3-D cell-based biosensing.     

白茯苓凝集素的研究

以中药白茯苓为材料,采用盐析、离子交换及凝胶过滤可纯化出快速蛋白液相谱（ＦＰＬＣ）纯的白茯苓凝集素（ＳＬＬ）。当其浓度为０．２５μｇ／ｍＬ时就能凝集兔红细胞,对人类Ａ,Ｂ,Ｏ型血细胞无作用。甲状腺球蛋白、卵粘蛋白和胃粘蛋白对ＳＬＬ的凝血活性有强抑制作用,而常见糖类对其无明显抑制作用。ＳＬＬ含中性糖１２．５％,凝胶过滤及ＦＰＬＣ测得分子量为３１０００,亚基分子量为８０００,表明ＳＬＬ可能由四个相同亚基组成。ＳＬＬ对酸、碱、热均有较高的耐受性,并且是一个强促有丝分裂原。     

The helical model of the nucleosome core.

A model of the nucleosome core is proposed based on a topologically linear array of histones attached sequentially to DNA. The linear complex folds helically forming a spring-like particle. Different variants of the particle are discussed (cylindrical springs with and without histone-histone contacts between turns of the helix, solenoidal spring). The model is consistent with known data about the nucleosome structure. Histones H3 and H4 have a special role in the model which is related also to the superstructure of chromatin.