bluuebunny/crossref_metadata_2025_split huggingface dataset:
Guanosine gel for sequence‐dependent separation of polymorphic ssDNA
Authors: Case William S. , Glinert Keren D. , LaBarge Sam , McGown Linda B. 
Published: July 2007

AbstractThe separation of fluorescent‐labeled ssDNA fragments of equal length based on differences in sequence was achieved through the use of guanosine gels (G‐gels) formed by guanosine‐5'‐monophosphate (GMP) in capillary gel electrokinetic chromatography (CGEKC) with LIF detection. Baseline resolution was achieved for homodimers and homopentamers of A, T, and C. G‐gel CGEKC provided better resolution than CZE, MEKC, or a sieving gel in CGE. Resolution improved with increasing GMP, indicating that the interaction is linked to structural organization of the G‐gel. Fluorescence intensity and anisotropy show that the order of interaction with G‐gels is T>C>A. We then investigated four conformationally similar, polymorphic 76‐mers with A/G substitutions that are utilized in forensic DNA typing. Resolution was achieved by CGEKC but not CZE or CGE. In CGEKC, the negatively charged G‐gels and oligonucleotides electromigrate toward the positive inlet while being driven by EOF to the negative outlet. The net forward velocity is the greatest for oligonucleotides most closely associated with the slower, more cumbersome G‐gel network. For the 76‐mers, resolution increases with increasing difference in guanosine content between strands and, for a given difference, with increasing total guanosines in the strands.
A design procedure for tied braced frames
Authors: Rossi Pier Paolo 
Published: July 2007

AbstractThe paper deals with the analysis of the seismic behaviour and design of tied braced frames (TBFs). The behavioural properties of TBFs are described and a comparison drawn with standard eccentrically braced frames. A design procedure is then proposed that aims to achieve optimal collapse seismic behaviour, i.e. a global collapse mechanism characterized by uniform plastic rotations of links. The procedure is based on the displacement‐based approach so as to achieve direct and efficient control of the peak ground acceleration of collapse. Applications are carried out on systems with different numbers of storeys and lengths of links to obtain confirmation of the accuracy of the design hypotheses and methodologies. Copyright © 2007 John Wiley & Sons, Ltd.
On the estimation of hysteretic energy demands for SDOF systems
Authors: Arroyo Danny , Ordaz Mario 
Published: July 2007

AbstractBased on a statistical study of the dynamic response of single degree of freedom (SDOF) systems subjected to earthquake ground motions, a rule to estimate hysteretic energy demands is proposed. Expressions for elastic–perfectly plastic, stiffness degrading and pinching SDOF systems were obtained. The proposed rule does not explicitly depend on the period of the system; instead, it depends on the elastic pseudo‐acceleration and elastic velocity spectra. It is shown that the proposed rule can be applied to compute hysteretic energy demands for systems located at different soil conditions. In addition, information about scatter and bias of the proposed rule is also presented. Copyright © 2007 John Wiley & Sons, Ltd.
Optimized isolation enables ex vivo analysis of microglia from various central nervous system regions
Authors: De Haas Alexander H. , Boddeke Hendricus W. G. M. , Brouwer Nieske , Biber Knut 
Published: July 2007

AbstractEx vivo analysis is an accurate and convenient way to study in vivo microglia phenotype and function. However, current microglia isolation protocols for ex vivo analysis show many differences in isolation steps (perfusion, removal of meninges and blood vessels, mechanical dissociation, enzymatic dissociation, density separation, immunomagnetic separation, and fluorescence‐activated cell sorting), often without addressing their effects on microglia purity, number, phenotype, and function. Therefore, the aim of this study was to provide an optimized isolation protocol with emphasis on microglia purity and number to enable ex vivo analysis of adult mouse microglia. The application of this protocol for ex vivo phenotype and functional analysis is corroborated by results from flow cytometry, gene expression analysis, chemotaxis, and phagocytosis assays. In addition, this study shows the possibility to analyze microglia isolated from various central nervous system regions such as optic nerve, striatum, hippocampus, spinal cord, cerebellum, and cerebral cortex. Furthermore, this is the first study presenting DRAQ5 as a superior alternative to propidium iodide for the discrimination between living and dead cells. DRAQ5 staining facilitated the identification of microglia upon flow cytometry without the need of additional fluorescent markers. Along with a favorable emission spectrum, DRAQ5 proved a valuable tool for flow cytometry of microglia. The presented optimized microglia isolation protocol for ex vivo analysis offers the opportunity to obtain more insight into both general and region‐specific microglia behavior. © 2007 Wiley‐Liss, Inc.
Characteristics of nutrient concentrations during low streamflow in Korean watersheds with paddy fields
Authors: Kim Jin S. , Kwun Soon‐Kuk , Oh Seung Y. 
Published: July 2007

AbstractWe investigated nutrient concentrations, during periods of low streamflow, from medium‐scale watersheds (5.1–15.3 km2) with paddy fields. Data were collected both during irrigation and non‐irrigation periods, from 1996 to 2000. Mean total nitrogen (TN) concentration during irrigation periods (2.6 mg l−1) was significantly lower than during non‐irrigation periods (6.2 mg l−1), most likely due to the dilution effect of higher discharge and nitrogen removal in the forest and paddy field by denitrification. Mean total phosphorus (TP) concentration during irrigation periods (0.13 mg l−1) was higher than during non‐irrigation periods (0.09 mg l−1). Therefore, the mean TN:TP ratio during irrigation periods was 20:1, compared to 67:1 during non‐irrigation periods; hence the possibility of cyanobacterial blooms was higher during the peak of irrigation. During irrigation periods, TN concentrations in the study watersheds displayed no relationship with discharge, similar to the finding for the paddy fields. Paddy field irrigation may impact on nitrogen concentrations in low streamflow at the watershed scale. Copyright © 2007 John Wiley & Sons, Ltd.
Daxx contains two nuclear localization signals and interacts with importin α3
Authors: Yeung Percy Luk , Chen Liuh‐Yow , Tsai Shih‐Chieh , Zhang Aihua , Chen J. Don 
Published: July 2007

AbstractDaxx plays a major role in several important signaling pathways including transcription and cell death. It has been postulated that Daxx regulates both events from the nucleus; however, the mechanism by which Daxx is localized in the nucleus remains obscure. Here we show that nuclear localization of Daxx is controlled by two independent signals and importin 3. Domain analysis reveals that Daxx contains two separate nuclear localizing domains. Site‐directed mutagenesis reveals that the basic aa sequence RLKRK at residues 227–231 (NLS1) is responsible for nuclear localization of N‐terminal domain, while aa sequence KKSRKEKK at residues 630–637 (NLS2) is responsible for nuclear localization of the C‐terminal domain. Mutations of a NLS consensus sequence RKKRR at residues 391–395 and several other basic aa clusters have no effect on Daxx nuclear localization. In full‐length Daxx, NLS1 contributes partially to nuclear localization, while NLS2 plays a major role. Markedly, it is essential to disrupt both NLS1 and NLS2 in order to completely block nuclear localization of the full‐length protein and to prevent its association with PML nuclear bodies. Furthermore, Daxx interacts selectively with importin α3 through its NLS1 and NLS2 sequences. Conversely, importin α3 utilizes two NLS‐binding sites for Daxx interaction, suggesting that the importin/mediates nuclear import of Daxx. Finally, we show that nuclear localization of Daxx is essential for its transcriptional effects on GR and p53. Together, these data unveil a molecular mechanism that controls nuclear localization of Daxx and support a nuclear role of Daxx in transcriptional regulation. J. Cell. Biochem. 103: 456–470, 2008. © 2007 Wiley‐Liss, Inc.
Cellular nucleic acid binding protein binds G‐rich single‐stranded nucleic acids and may function as a nucleic acid chaperone
Authors: Armas Pablo , Nasif Sofía , Calcaterra Nora B. 
Published: July 2007

AbstractCellular nucleic acid binding protein (CNBP) is a small single‐stranded nucleic acid binding protein made of seven Zn knuckles and an Arg‐Gly rich box. CNBP is strikingly conserved among vertebrates and was reported to play broad‐spectrum functions in eukaryotic cells biology. Neither its biological function nor its mechanisms of action were elucidated yet. The main goal of this work was to gain further insights into the CNBP biochemical and molecular features. We studied Bufo arenarum CNBP (bCNBP) binding to single‐stranded nucleic acid probes representing the main reported CNBP putative targets. We report that, although bCNBP is able to bind RNA and single‐stranded DNA (ssDNA) probes in vitro, it binds RNA as a preformed dimer whereas both monomer and dimer are able to bind to ssDNA. A systematic analysis of variant probes shows that the preferred bCNBP targets contain unpaired guanosine‐rich stretches. These data expand the knowledge about CNBP binding stoichiometry and begins to dissect the main features of CNBP nucleic acid targets. Besides, we show that bCNBP presents a highly disordered predicted structure and promotes the annealing and melting of nucleic acids in vitro. These features are typical of proteins that function as nucleic acid chaperones. Based on these data, we propose that CNBP may function as a nucleic acid chaperone through binding, remodeling, and stabilizing nucleic acids secondary structures. This novel CNBP biochemical activity broadens the field of study about its biological function and may be the basis to understand the diverse ways in which CNBP controls gene expression. J. Cell. Biochem. 103: 1013–1036, 2008. © 2007 Wiley‐Liss, Inc.
The Role of heat shock protein 27 in extravillous trophoblast differentiation
Authors: Matalon S. Tartakover , Drucker L. , Fishman A. , Ornoy A. , Lishner M. 
Published: July 2007

AbstractTrophoblast cells from placental explants differentiate in culture to extravillous trophoblast cells (EVT cells). During trophoblast differentiation heat‐shock‐protein‐27 (HSP27) mRNA and multidrug‐resistance‐protein‐5 (MRP5, transporter of cyclic nucleotides) expression are increased. HSP27 is a regulator of actin filaments structure and dynamic, has a role in cell differentiation and may affect NF‐kB activity. In this study we aimed to assess HSP27 level in trophoblast cells and its correlation with motility and differentiation related processes [MMPs activity, nitric oxide (NO), inducible nitric oxide synthase (iNOS), proliferation and MRP5 levels]. We evaluated HSP27 expression in a first trimester human trophoblast explants model designed to assess EVT cells differentiation/migration with/without 6‐mercaptopurine (6MP, an EVT inhibitor of migration). We found that HSP27 level is expressed in the nucleous and cytoplasm of non‐proliferting villous‐trophoblast cells (negative for Ki67) and in the cell periphery and cytoplasm of motile EVT cells. Moreover, 6MP decreased HSP27 nucleous expression that was associated with inhibited MMP2 activity and NO production. Also decreased iNOS expression and increased MRP5 mRNA levels were observed. In conclusion, HSP27 expression is modulated in concordance with migration dependent parameters in trophoblast cells. J. Cell. Biochem. 103: 719–729, 2008. © 2007 Wiley‐Liss, Inc.
Aneuploidy and cancer
Authors: Chi Ya‐Hui , Jeang Kuan‐Teh 
Published: July 2007

AbstractThe cell's euploid status is influenced by, amongst other mechanisms, an intact spindle assembly checkpoint (SAC), an accurate centrosome cycle, and proper cytokinesis. Studies in mammalian cells suggest that dysregulated SAC function, centrosome cycle, and cytokinesis can all contribute significantly to aneuploidy. Of interest, human cancers are frequently aneuploid and show altered expression in SAC genes. The SAC is a multi‐protein complex that monitors against mis‐segregation of sister chromatids. Several recent experimental mouse models have suggested a link between weakened SAC and in vivo tumorigenesis. Here, we review in brief some mechanisms which contribute to cellular aneuploidy and offer a perspective on the relationship between aneuploidy and human cancers. J. Cell. Biochem. 102: 531–538, 2007. © 2007 Wiley‐Liss, Inc.
Histone deacetylases in control of skeletogenesis
Authors: Westendorf Jennifer J. 
Published: July 2007

AbstractSkeletogenesis occurs continuously during the lifespan of vertebrate organisms. In development, the skeleton is patterned and modeled until each bone achieves its optimal shape and full size. During adults, the skeleton is remodeled to maintain strength and release calcium. The bone‐resorbing and bone‐forming activities of osteoclasts and osteoblasts, respectively, are tightly coupled to maintain optimal skeletal health; however, during aging and disease, these cells can become uncoupled, adversely affecting skeletal health and strength. Histone deacetylases have emerged as important regulators of endochondral bone formation, osteoblast maturation and osteoclast survival. Histone deacetylases are inhibited by small molecules that are approved and/or in clinical trials as cancer therapeutic drugs or anti‐epileptic agents. In this article, the roles of histone deacetylases and effects of histone deacetylase inhibitors on bone and cartilage cells are reviewed. J. Cell. Biochem. 102: 332–340, 2007. © 2007 Wiley‐Liss, Inc.
Light and transmission electron microscopy study of the peripheral olfactory organ of the guppy, Poecilia reticulata (Teleostei, Poecilidae)
Authors: Lazzari Maurizio , Bettini Simone , Ciani Franco , Franceschini Valeria 
Published: July 2007

AbstractA study of the peripheral olfactory organ, with special attention to the olfactory epithelium, has been carried out in the guppy (Poecilia reticulata). Guppy is well known to have a vision‐based sexual behavior. The olfactory chamber caudally opens directly in an accessory nasal sac, which is bent medially and gives rise to two recesses that can be considered secondary accessory nasal sacs, antero‐medial and postero‐medial, respectively. The sensory epithelium, which lines only the medial wall of the nasal cavity, is basically flat rising in a very low lamella only in the posterior part. The olfactory receptors are not evenly distributed in the olfactory mucosa, but aggregate in shallow folds separated by epithelial cells with evident microridges. Ciliated olfactory sensory neurons and microvillous olfactory sensory neurons are clearly identified by transmission electron microscopy (TEM). Scarce crypt olfactory neurons are found throughout the sensory folds. The nasal sacs indicates the capacity to regulate the flow of odorant molecules over the sensory epithelium, possibly through a pump‐like mechanism associated with gill ventilation. The organization of the olfactory organ in guppy is simple and reminds what is found in early posthatching stages of fish which at the adult state have a well developed olfactory organ. This simple organization supports the idea that the guppy rely on olfaction less than other fish species provided with more extended olfactory receptorial surface. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Polarized light imaging of white matter architecture
Authors: Larsen Luiza , Griffin Lewis D. , GRäßel David , Witte Otto W. , Axer Hubertus 
Published: July 2007

AbstractPolarized light imaging (PLI) is a method to image fiber orientation in gross histological brain sections based on the birefringent properties of the myelin sheaths. The method uses the transmission of polarized light to quantitatively estimate the fiber orientation and inclination angles at every point of the imaged section. Multiple sections can be assembled into a 3D volume, from which the 3D extent of fiber tracts can be extracted. This article describes the physical principles of PLI and describes two major applications of the method: the imaging of white matter orientation of the rat brain and the generation of fiber orientation maps of the human brain in white and gray matter. The strengths and weaknesses of the method are set out. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Method of imaging low density lipoproteins by atomic force microscopy
Authors: Chouinard Julie A. , Khalil Abdelouahed , Vermette Patrick 
Published: July 2007

AbstractThis short paper reports a simple method to image low density lipoproteins (LDL) using atomic force microscopy (AFM). This instrument allows imaging of biological samples in liquid and presents the advantage of needing no sample preparation such as staining or fixation that may affect their general structure. Dimensions (diameter and height) of individual LDL particles were successfully measured. AFM imaging revealed that LDL have a quasi‐spherical structure on the x and y axis with an oblate spheroid structure in the z axis (i.e., height). LDLs were found to have an average diameter of 23 ± 3 nm. The obtained mean height was 10 ± 2 nm. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Surface damage induced by FIB milling and imaging of biological samples is controllable
Authors: Drobne Damjana , Milani Marziale , Lešer Vladka , Tatti Francesco 
Published: July 2007

AbstractFocused ion beam (FIB) techniques are among the most important tools for the nanostructuring of surfaces. We used the FIB/SEM (scanning electron microscope) for milling and imaging of digestive gland cells. The aim of our study was to document the interactions of FIB with the surface of the biological sample during FIB investigation, to identify the classes of artifacts, and to test procedures that could induce the quality of FIB milled sections by reducing the artifacts. The digestive gland cells were prepared for conventional SEM. During FIB/SEM operation we induced and enhanced artifacts. The results show that FIB operation on biological tissue affected the area of the sample where ion beam was rastering. We describe the FIB‐induced surface major artifacts as a melting‐like effect, sweating‐like effect, morphological deformations, and gallium (Ga+) implantation. The FIB induced surface artifacts caused by incident Ga+ ions were reduced by the application of a protective platinum strip on the surface exposed to the beam and by a suitable selection of operation protocol. We recommend the same sample preparation methods, FIB protocol for milling and imaging to be used also for other biological samples. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Single‐ and two‐photon spectral imaging of intrinsic fluorescence of transformed human hepatocytes
Authors: Rajwa Bartek , Bernas Tytus , Acker Helmut , Dobrucki Jurek , Robinson J.P. 
Published: July 2007

AbstractAutofluorescence (AF) originating from the cytoplasmic region of mammalian cells has been thoroughly investigated; however, AF from plasma membranes of viable intact cells is less well known, and has been mentioned only in a few older publications. Herein, we report results describing single‐ and two‐photon spectral properties of a strong yellowish‐green AF confined to the plasma‐membrane region of transformed human hepatocytes (HepG2) grown in vitro as small three‐dimensional aggregates or as monolayers. The excitation–emission characteristics of the membrane AF indicate that it may originate from a flavin derivative. Furthermore, the AF was closely associated with the plasma membranes of HepG2 cells, and its presence and intensity were dependent on cell metabolic state, membrane integrity and presence of reducing agents. This AF could be detected both in live intact cells and in formaldehyde‐fixed cells. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Authentication of the 31 species of toxic and potent Chinese Materia medica (T/PCMM) by microscopic technique, part 1: Three kinds of toxic and potent animal CMM
Authors: Xia Li , Bai Li‐Ping , Yi Ling , Liu Bin‐Bin , Chu Chu , Liang Zhi‐Tao , Li Ping , Jiang Zhi‐Hong , Zhao Zhong‐Zhen 
Published: July 2007

AbstractMicroscopic authentication is an effective method for quality control of Chinese Materia Medica (CMM) because of its speed, convenience and low cost. However, the application of modern microscopic technique in quality evaluation of Toxic and Potent Chinese Materia Medica (T/PCMM) of animal origin is seldom reported. This gap in published knowledge is increasingly serious because confusion in T/PCMM has led to serious medical problems in China and other countries in recent years. To ensure the safe and effective use of T/PCMM, an accurate and convenient method, based on macroscopic and microscopic techniques, was developed for the authentication of animal T/PCMM. The color microscopic photos of the crude drug were acquired with the light microscope, and from these their morphological and microscopic characters were described. The present method was successfully applied in the analysis of 31 T/PCMM including 17 samples originating from plants, 3 from animals, 9 from minerals, and the remaining 2 from secreta. The macro‐ and microscopic characters of three animal T/PCMM, namely Mylabris (Mylabris phalerata or Mylabris cichorii), Huechys (Huechys sanguinea), and Lytta (Lytta caraganae) were conclusively determined and are here presented. The results demonstrated that it was feasible to use the present microscopic characters for the authentication of the above three animal T/PCMM. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Construction and evaluation of a wavelet‐based focus measure for microscopy imaging
Authors: Xie Hui , Rong Weibin , Sun Lining 
Published: July 2007

AbstractMicroscopy imaging can not achieve both high resolution and wide image space simultaneously. Autofocusing is of fundamental importance to automated micromanipulation. This article proposes a new wavelet‐based focus measure, which is defined as a ratio of high frequency coefficients and low frequency coefficients. 8 series of 49 microscope images each acquired under five magnifications are used to comprehensively compare the performance of our focus measure with the classic and popular focus measures, including Normalized Variance, Entropy, Energy Laplace and wavelet‐based high frequency focus measures. The robustness of these focus measures is evaluated using noisy image sequences corrupted by Gaussian white noise with standard deviations (STD) 5 and 15. An evaluation methodology is proposed, based on which these 5 focus measures are ranked. Experimental results show that the proposed focus measure can provide significantly the best overall performance and robustness. This focus measure can be widely applied to the automated biological and biomedical applications. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.