Sensitivity map of laser tweezers Raman spectroscopy for single-cell analysis of colorectal cancer

Raman spectroscopy on single, living epithelial cells captured in a laser trap is shown to have diagnostic power over colorectal cancer. This new single-cell technology comprises three major components: primary culture processing of human tissue samples to produce single-cell suspensions, Raman detection on singly trapped cells, and diagnoses of the cells by artificial neural network classifications. it is compared with DNA flow cytometry for similarities and differences. Its advantages over tissue Raman spectroscopy are also discussed. In the actual construction of a diagnostic model for colorectal cancer, real patient data were taken to generate a training set of 320 Raman spectra and, a test set of 80. By incorporating outlier corrections to a conventional binary neural classifier, our network accomplished significantly better predictions than logistic regressions, with sensitivity improved from 77.5% to 86.3% and specificity improved from 81.3% to 86.3% for the training set and moderate improvements for the test set. Most important, the network approach enables a sensitivity map analysis to quantitate the relevance of each Raman band to the normal-to-cancer transform at the cell level. Our technique has direct clinic applications for diagnosing cancers and basic science potential in the study of cell dynamics of carcinogenesis. (C) 2007 Society of Photo-Optical Instrumentation Engineers.

Sensitivity map of laser tweezers Raman spectroscopy for single-cell analysis of colorectal cancer

Raman spectroscopy on single, living epithelial cells captured in a laser trap is shown to have diagnostic power over colorectal cancer. This new single-cell technology comprises three major components: primary culture processing of human tissue samples to produce single-cell suspensions, Raman detection on singly trapped cells, and diagnoses of the cells by artificial neural network classifications. it is compared with DNA flow cytometry for similarities and differences. Its advantages over tissue Raman spectroscopy are also discussed. In the actual construction of a diagnostic model for colorectal cancer, real patient data were taken to generate a training set of 320 Raman spectra and, a test set of 80. By incorporating outlier corrections to a conventional binary neural classifier, our network accomplished significantly better predictions than logistic regressions, with sensitivity improved from 77.5% to 86.3% and specificity improved from 81.3% to 86.3% for the training set and moderate improvements for the test set. Most important, the network approach enables a sensitivity map analysis to quantitate the relevance of each Raman band to the normal-to-cancer transform at the cell level. Our technique has direct clinic applications for diagnosing cancers and basic science potential in the study of cell dynamics of carcinogenesis. (C) 2007 Society of Photo-Optical Instrumentation Engineers.

Comparative Analysis of Five Different Homologous Feeder Cell Lines in the Ability to Support Rhesus Embryonic Stem Cells

我们以前的研究建立了五株猕猴饲养层细胞系来支持猕猴胚胎干细胞(rESCs)的生长:一岁猴耳皮肤成纤维细胞(MESFs)、两岁猴输卵管成纤维细胞(MOFs)、成年猴卵泡颗粒成纤维样细胞(MFGs)、成年猴卵泡颗粒上皮样细胞(MFGEs),以及MESFs的克隆成纤维细胞(CMESFs).我们发现MESFs、CMESFs、MOFs和MFGs,而不足MFGEs支持猕猴胚胎干细胞(rESCs,rhesus embryonic stem cells)的生长.通过半定量PCR的方法,我们在支持性的饲养层细胞中检测到了一些基因的高表达.在本研究中,我们运用Affymetrix公司的GeneChip Rhesus Macaque Genome Array芯片来研究这五株同源饲养层的表达谱,希望发现哪些细胞因子和信号通路在维持rESCs中起到重要作用.结果表明,除MFGE外,包括GREM2、bFGF,、KITLG,、DKK3、GREM1、AREG、SERPINF1和LTBF1等八个基因的mRNA在支持性的饲养层细胞中高表达.本研究结果提示,很多信号通路在支持rESCs的未分化生长和多潜能性方面可能起到了冗余的作用.

Inductive expression and characterization analysis of Paralichthys olivaceus pigment epithelium-derived factor in a virally infected cell line

Pigment epithelium-derived factor (PEDF) is acknowledged to be a non-inhibitory member of the serine protease inhibitor (serpin) superfamily, with antiangiogenesis, and neuroprotective and immumoregulatory function, mainly in the tissues of nervous system. Here, A PEDF gene homolog, Paralichthys olivaceus PEDF (PoPEDF), was isolated from flounder embryonic cells (FEC) treated with UV-inactivated Grass carp hemorrhage virus (GCHV) and subsequently identified as a differentially expressed gene. The full length of PoPEDF cDNA is 1803 bp with an open reading frame of 1212 bp encoding a 403-amino-acid protein. This deduced protein contains an N-terminal signal peptide, a glycosylation site, a consensus serpin motif, and a 34-mer and a 44-mer fragment, all of which are very conserved in the PEDF family. PoPEDF gene exhibits a conserved exon-intron arrangement with 8 exons and 7 introns. This conserved evolutionary relationship was further confirmed by a phylogenetic analysis, where fish PEDFs and mammalian members formed a well-supported clade. Constitutive expression of PoPEDF was widely detected in many tissues. In response to UV-inactivated GCHV or poly(I:C), PEDF mRNA was upregulated in FEC cells with time. This is the first report on the transcriptional induction of PEDF in virally infected cells. (C) 2005 Elsevier Inc. All rights reserved.

Analysis of lateral current spreading in solar cell devices by spatially-resolved electroluminescence

Spatially-resolved electroluminescence (EL) images from solar cells contain information of local current distribution. By theoretical analysis of the EL intensity distribution, the current density distribution under a certain current bias and the sheet resistance can be obtained quantitatively. Two-dimensional numerical simulation of the current density distribution is employed to a GaInP cell, which agrees very well with the experimental results. A reciprocity theorem for current spreading is found and used to interpret the EL images from the viewpoint of current extraction. The optimization of front electrodes is discussed based on the results. (C) 2010 American Institute of Physics. [doi:10.1063/1.3431390]

Analysis of leakage current in GaAs micro-solar cell arrays

The output characteristics of micro-solar cell arrays are analyzed on the basis of a modified model in which the shunt resistance between cell lines results in current leakage. The modification mainly consists of adding a shunt resistor network to the traditional model. The obtained results agree well with the reported experimental results. The calculation results demonstrate that leakage current in substrate affects seriously the performance of GaAs micro- solar cell arrays. The performance of arrays can be improved by reducing the number of cells per line. In addition, at a certain level of integration, an appropriate space occupancy rate of the single cell is recommended for ensuring high open circuit voltages, and it is more appropriate to set the rates at 80%-90% through the calculation.

Internal quantum efficiency analysis of solar cell by genetic algorithm

To investigate factors limiting the performance of a GaAs solar cell, genetic algorithm is employed to fit the experimentally measured internal quantum efficiency (IQE) in the full spectra range. The device parameters such as diffusion lengths and surface recombination velocities are extracted. Electron beam induced current (EBIC) is performed in the base region of the cell with obtained diffusion length agreeing with the fit result. The advantage of genetic algorithm is illustrated.

Structural ordering and interface morphology in symmetrically strained (GaIn)As/Ga(PAs) superlattices grown on off-oriented GaAs(100)

In this work we investigate the structural properties of symmetrically strained (GaIn)As/GaAs/Ga(PAs)/GaAs superlattices by means of x-ray diffraction, reciprocal-space mapping, and x-ray reflectivity. The multilayers were grown by metalorganic vapor-phase epitaxy on (001) GaAs substrates intentionally off-oriented towards one of the nearest [110] directions. High-resolution triple-crystal reciprocal-space maps recorded for different azimuth angles in the vicinity of the (004) Bragg diffraction clearly show a double periodicity of the x-ray peak intensity that can be ascribed to a lateral and a vertical periodicity occurring parallel and perpendicular to the growth surface. Moreover, from the intensity modulation of the satellite peaks, a lateral-strain gradient within the epilayer unit cell is found, varying from a tensile to a compressive strain. Thus, the substrate off-orientation promotes a lateral modulation of the layer thickness (ordered interface roughness) and of the lattice strain, giving rise to laterally ordered macrosteps. In this respect, contour maps of the specular reflected beam in the vicinity of the (000) reciprocal lattice point were recorded in order to inspect the vertical and lateral interface roughness correlation, A semiquantitative analysis of our results shows that the interface morphology and roughness is greatly influenced by the off-orientation angle and the lateral strain distribution. Two mean spatial wavelengths can be determined, one corresponding exactly to the macrostep periodicity and the other indicating a further interface waviness along the macrosteps. The same spatial periodicities were found on the surface by atomic-force-microscopy images confirming the x-ray results and revealing a strong vertical correlation of the interfaces up to the outer surface.

Analysis of leakage current in GaAs micro-solar cell arrays

The output characteristics of micro-solar cell arrays are analyzed on the basis of a modified model in which the shunt resistance between cell lines results in current leakage. The modification mainly consists of adding a shunt resistor network to the traditional model. The obtained results agree well with the reported experimental results. The calculation results demonstrate that leakage current in substrate affects seriously the performance of GaAs micro- solar cell arrays. The performance of arrays can be improved by reducing the number of cells per line. In addition, at a certain level of integration, an appropriate space occupancy rate of the single cell is recommended for ensuring high open circuit voltages, and it is more appropriate to set the rates at 80%-90% through the calculation.

On Combining Morphological Component Analysis and Concentric Morphology Model for Mammographic Mass Detection

Mammographic mass detection is an important task for the early diagnosis of breast cancer. However, it is difficult to distinguish masses from normal regions because of their abundant morphological characteristics and ambiguous margins. To improve the mass detection performance, it is essential to effectively preprocess mammogram to preserve both the intensity distribution and morphological characteristics of regions. In this paper, morphological component analysis is first introduced to decompose a mammogram into a piecewise-smooth component and a texture component. The former is utilized in our detection scheme as it effectively suppresses both structural noises and effects of blood vessels. Then, we propose two novel concentric layer criteria to detect different types of suspicious regions in a mammogram. The combination is evaluated based on the Digital Database for Screening Mammography, where 100 malignant cases and 50 benign cases are utilized. The sensitivity of the proposed scheme is 99% in malignant, 88% in benign, and 95.3% in all types of cases. The results show that the proposed detection scheme achieves satisfactory detection performance and preferable compromises between sensitivity and false positive rates.

Miniaturized tris(2,2 '-bipyridyl)ruthenium(II) electrochemiluminescence detection cell for capillary electrophoresis and flow injection analysis

The design and performance of a miniaturized chip-type tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy)(3)(2+)] electrochemiluminescence (ECL) detection cell suitable for both capillary electrophoresis (CE) and flow injection (FI) analysis are described. The cell was fabricated from two pieces of glass (20 x 15 x 1.7 mm), and the 0.5-mm-diameter platinum disk was used as working electrode held at +1.15 V (vs silver wire quasi-reference), the stainless steel guide tubing as counter electrode, and the silver wire as quasi-reference electrode. The performance traits of the cell in both CE and FI modes were evaluated using tripropylamine, proline, and oxalate and compared favorably to those reported for CE and FI detection cells. The advantages of versatility, sensitivity, and accuracy make the device attractive for the routine analysis of amine-containing species or oxalate by CE and FI with Ru(bPY)(3)(2divided by) ECL detection.

Variations in morphology and PSII photosynthetic capabilities during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi) Papenfuss (Gracilariales, Rhodophyta)

Background: Red algae are primitive photosynthetic eukaryotes, whose spores are ideal subjects for studies of photosynthesis and development. Although the development of red alga spores has received considerable research attention, few studies have focused on the detailed morphological and photosynthetic changes that occur during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi) Papenfuss (Gracilariales, Rhodophyta). Herein, we documented these changes in this species of red algae. Results: In the tetraspores, we observed two types of division, cruciate and zonate, and both could develop into multicellular bodies (disks). During the first 84 hours, tetraspores divided several times, but the diameter of the disks changed very little; thereafter, the diameter increased significantly. Scanning electron microscopy observations and analysis of histological sections revealed that the natural shape of the disk remains tapered over time, and the erect frond grows from the central protrusion of the disk. Cultivation of tissue from excised disks demonstrated that the central protrusion of the disk is essential for initiation of the erect frond. Photosynthetic (i.e., PSII) activities were measured using chlorophyll fluorescence analysis. The results indicated that freshly released tetraspores retained limited PSII photosynthetic capabilities; when the tetraspores attached to a substrate, those capabilities increased significantly. In the disk, the PSII activity of both marginal and central cells was similar, although some degree of morphological polarity was present; the PSII photosynthetic capabilities in young germling exhibited an apico-basal gradient. Conclusions: Attachment of tetraspores to a substrate significantly enhanced their PSII photosynthetic capabilities, and triggered further development. The central protrusion of the disk is the growth point, may have transfer of nutritive material with the marginal cells. Within the young germling, the hetero-distribution of PSII photosynthetic capabilities might be due to the differences in cell functions.

Analysis of three marine fish cell lines by RAPD assay

We tested the applicability of the random amplified polymorphic deoxyribonucleic acid (RAPD) analysis for identification of three marine fish cell lines FG. SPH, and RSBK and as a possible tool to detect cross-contamination. Sixth commercial 10-mer RAPD primers were tested on the cell lines and on samples collected from individual fish. The results obtained showed that the cell lines could be identified to the correspondent species on the basis of identical Patterns produced by 35-48% of the primers tested. the total mean similarity indices for cell lines versus correspondent species of individual fish ranged from 0.825 to 0.851. indicating the existence of genetic variation in these cell lines in relation to the species of their origin. Also, four primers, which gave a monomorphic hand pattern within species/line, but different among the species/line, were obtained. These primers can be useful for identification of these cell lines and for characterization of the genetic variation of these cell lines in relation to the species of their origin. This supported the use of RAPD analysis as an effective tool in species identification and cross-contamination test among different cell lines.