bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of semi-isostatic densification on anatomy and cell-shape recovery on soaking
Authors: Blomberg Jonas , Persson Bengt , Bexell Ulf 
Published: May 2006

Abstract
Images obtained by scanning electron microscopy (SEM) helped to clarify the question as to how anatomy influences the deformation on compression and the springback of densified wood on water soaking. Transverse sections of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), black alder (Alnus glutinosa), Swedish aspen (Populus tremula), European birch (Betula pubescens), European beech (Fagus sylvatica) and pedunculate oak (Quercus robur) were studied. Wood is reinforced with rays in the radial direction and with dense latewood in the tangential direction. When strained radially, rays buckle or tilt tangentially. Softwoods were mainly compressed radially, owing to low number of rays and since latewood is much denser than earlywood. The diffuse-porous hardwoods with low density variation between latewood and earlywood were mainly deformed tangentially, except birch, which has high density at the annual ring border and is mainly compressed radially. The ring-porous hardwoods were relatively equally deformed in the radial and tangential directions because of the high number of rays and high latewood density. Moisture-induced springback (shape recovery) was proportional to the degree of compression. Rays remained deformed, which also influenced the surrounding wood. Longitudinal wood cells almost resumed their original shape. Wood with low density and a low degree of compression showed the highest structural recovery. Shearing deformation was particularly pronounced and permanent in woods with high strength anisotropy. Thin-walled and sheared cells, such as earlywood in softwood, tended to crack on compression. Cracks usually stopped at the middle lamella and had a lesser influence on strength properties than for lumen-to-lumen cracks.
Tumor Vascular Area Correlates with Photosensitizer Uptake: Analysis of Verteporfin Microvascular Delivery in the Dunning Rat Prostate Tumor
Authors: Zhou Xiaodong , Chen Bin , Hoopes P. Jack , Hasan Tayyaba , Pogue Brian W. 
Published: May 2006

ABSTRACTThe parameters that limit supply of photosensitizer to the cancer cells in a solid tumor were systematically analyzed with the use of microvascular transport modeling and histology data from frozen sections. In particular, the vascular permeability transport coefficient and the effective interstitial diffusion coefficient were quantified for Verteporfin‐for‐Injection delivery of benzoporphyrin derivative (BPD). Orthotopic tumors had higher permeability and diffusion coefficients (Pd= 0.036 μm and D= 1.6 μm2/s, respectively) as compared to subcu‐taneously grown tumors (Pd= 0.025 μm/s and D= 0.9 μm2/s, respectively), likely due to the fact that the vessel patterns are more homogeneous orthotopically. In general, large intersubject and intratumor variability exist in the verteporfin concentration, in the range of 25% in plasma concentration and in the range of 20% for tissue concentrations, predominantly due to these microregional variations in transport. However, the average individual uptake of photosensitizer in tumor tissue was only correlated to the total vascular area within the tumor (R2= 64.1%, P < 0.001). The data are consistent with a view that microregional variation in the vascular permeability and interstitial diffusion rate contribute the spatial heterogeneity observed in verteporfin uptake, but that average supply to the tissue is limited by the total area of perfused blood vessels. This study presents a method to systematically analyze micro‐heterogeneity as well as possible methods to increase delivery and homogeneity of photosensitizer within tumor tissue.
Junctional Epithelium in Rats Is Characterized by Slow Cell Proliferation
Authors: Willberg Jaana , Syrjänen Stina , Hormia Marketta 
Published: May 2006

Background: The integrity of junctional epithelium (JE) and a firm epithelial adhesion to the tooth surface are maintained by the balance between cell proliferation and cell death. Maintaining the JE structure is essential for the protection of periodontal connective tissues against oral microbes. In this study, the proliferative activity and the expression of caspase 3, a cysteine protease associated with cell death, were studied in rat JE and other epithelial structures during molar tooth development.Methods: Fourteen rats aged 10 to 70 days were injected with bromodeoxyuridine (BrdU). Samples of first and second molars were selected for immunohistochemical staining. BrdU incorporation was studied in oral epithelium (OE) covering the erupting tooth, reduced enamel epithelium (REE), and gingival epithelium (GE), sulcular epithelium (SE), and JE. Samples were also subjected to immunohistochemical analysis for proliferating cell nuclear antigen (PCNA) and caspase 3.Results: The basal cells of the GE were actively proliferating, but in the JE, only a few cells were positive for BrdU or PCNA immunostaining. Some outer REE cells were proliferating during tooth eruption. Caspase 3 expression was in specific areas of REE after completion of amelogenesis.Conclusions: Results showed slow proliferative activity in the rat JE. However, specific studies on cellular turnover and cell migration are needed to understand tissue homeostasis in this area.
Characterization and comparison of polyurethane networks prepared using soybean‐based polyols with varying hydroxyl content and their blends with petroleum‐based polyols
Authors: Pechar T. W. , Sohn S. , Wilkes G. L. , Ghosh S. , Frazier C. E. , Fornof A. , Long T. E. 
Published: May 2006

AbstractPolyurethane Networks (PUNs) were synthesized using polyols derived from soybean oil, petroleum, or a blend of the two in conjunction with diisocyanate. The soybean‐based polyols (SBPs) were prepared using air oxidation, or by hydroxylating epoxidized soybean oil. Some of the networks were subjected to several solvents to determine their respective swelling behavior and solubility parameters. Sol‐fractions were also determined, and DMA experiments were utilized to monitor the changes in storage modulus and tan δ with temperature for networks with sol and with the sol extracted. A linear relationship was noted between the hydroxyl number of a SBP and the glass transition temperature of its corresponding unextracted PU network within the range of hydroxyl numbers (i.e., 55–237 mg KOH/g) and glass transition temperatures (i.e., −21–+83°C) encountered in this work. This same linear relationship was realized between the weighted hydroxyl number of soy and petroleum‐based polyol blends and the glass transition temperature of the resulting unextracted and extracted network PUs within the ranges utilized in this study (i.e., 44–57 mg KOH/g, −54–19°C). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1432–1443, 2006
RNA interference of sialidase improves glycoprotein sialic acid content consistency
Authors: Ngantung Frederyk A. , Miller Peter G. , Brushett Fikile R. , Tang Goh Lin , Wang Daniel I.C. 
Published: May 2006

AbstractAn important challenge facing therapeutic protein production in mammalian cell culture is the cleavage of terminal sialic acids on recombinant protein glycans by the glycosidase enzymes released by lysed cells into the supernatant. This undesired phenomenon results in a protein product which is rapidly cleared from the plasma by asialoglycoprotein receptors in the liver. In this study, RNA interference was utilized as a genetic approach to silence the activity of sialidase, a glycosidase responsible for cleaving terminal sialic acids on IFN‐γ produced by Chinese Hamster Ovary (CHO) cells. We first identified a 21‐nt double stranded siRNA that reduced endogenous sialidase mRNA and protein activity levels. Potency of each siRNA sequences was compared using real time RT‐PCR and a sialidase activity assay. We next integrated the siRNA sequence into CHO cells, allowing production and selection of stable cell lines. We isolated stable clones with sialidase activity reduced by over 60% as compared to the control cell line. Micellar electrokinetic chromatography (MEKC), thiobarbituric acid assay (TAA), and high performance anion exchange chromatography (HPAEC) coupled to amperometric detection were performed to analyze glycan site occupancy, sialic acid content, and distribution of asialo‐/sialylated‐glycan structures, respectively. Two of the stable clones successfully retained the full sialic acid content of the recombinant IFN‐γ, even upon cells' death. This was comparable to the case where a chemically synthesized sialidase inhibitor was used. These results demonstrated that RNA interference of sialidase can prevent the desialylation problem in glycoprotein production, resulting improved protein quality during the entire cell culture process. © 2006 Wiley Periodicals, Inc.
A Highly Tunable Family of Chiral Bisphospholanes for Rh‐Catalyzed Enantioselective Hydrogenation Reactions
Authors: Holz Jens , Zayas Odalys , Jiao Haijun , Baumann Wolfgang , Spannenberg Anke , Monsees Axel , Riermeier Thomas H. , Almena Juan , Kadyrov Renat , Börner Armin 
Published: May 2006

AbstractA set of 16 new and closely related bisphospholane ligands have been prepared by using a highly flexible and convergent approach. Each synthesis can be performed on an industrially relevant scale. The bisphosphines differ in the nature of the bridge connecting both phospholane units. Bridges are formed by three‐, four‐, five‐ and six‐membered heterocyclic or alicyclic rings. Bisphospholanes and their Rh‐precatalysts have been investigated by using results of theoretical calculations (DFT) and analytic measurements (31P and 103Rh NMR spectroscopy, X‐ray structure analysis). The studies showed that catalysts based on ligands with maleic anhydride or maleimide bridges give constantly superior enantioselectivities in methanol as the solvent. This may account for optimised steric and electronic effects. However, by changing the solvent catalysts with other backbones can give rise to excellent results. This gives proof that simple correlations between steric and electronic properties and results in the enantioselective hydrogenation frequently claimed in literature are not general.
Reproducible and inducible knockdown of gene expression in mice
Authors: Yu Jing , McMahon Andrew P. 
Published: May 2006

AbstractRNA interference (RNAi) has emerged as an efficient approach for rapid analysis of gene function. In mammalian cells, vector‐based expression of small hairpin RNAs (shRNA) produces potent and stable gene knockdown effects. An inducible RNAi system with reproducible levels of siRNA expression will extend the usefulness of this methodology to the identification of gene functions within the developing or adult mouse. We present evidence that an RNA polymerase III‐driven U6 promoter with stuffer sequences flanked by loxP sites inserted at three different sites within the promoter drives shRNA expression in a Cre recombinase‐dependent manner. We utilized this approach to develop a generic strategy for the reproducible knockdown of gene expression in mice. By placing the inducible shRNA cassette into the ROSA26 locus of the mouse, we were able to generate reproducible levels of controlled expression of shRNA to produce discernable phenotypes in vitro and in vivo. This approach circumvents the prescreening of random integration in embryonic stem cell clones and further enables conditional gene knockdown with temporal and/or tissue specificity. This methodology should expedite large‐scale functional studies. genesis 44:252–261, 2006. Published 2006 Wiley‐Liss, Inc.
More results on perfect (3,3,6k + 4; 6k − 2)‐threshold schemes
Authors: Ji L. 
Published: May 2006

AbstractA (2,3)‐packing on X is a pair (X,$\cal A$), where $\cal A$ is a set of 3‐subsets (called blocks) of X, such that any pair of distinct points from X occurs together in at most one block. Its leave is a graph (X,E) such that E consists of all the pairs which do not appear in any block of $\cal A$. In this article, we shall construct a set of 6k − 2 disjoint (2,3)‐packings of order 6k + 4 with K1,3 ∪ 3kK2 or G1 ∪ (3k − 1)K2 as their common leave for any integer k ≥ 1 with a few possible exceptions (G1 is a special graph of order 6). Such a system can be used to construct perfect threshold schemes as noted by Schellenberg and Stinson (1989). © 2006 Wiley Periodicals, Inc. J Combin Designs
Direct determination of ciprofloxacin by mass spectrometry after a two‐step solid‐phase extraction using a molecularly imprinted polymer
Authors: Caro Ester , Marcé Rosa M. , Cormack Peter A. G. , Sherrington David C. , Borrull Francesc 
Published: May 2006

AbstractA molecularly imprinted polymer (MIP) has been prepared for the first time with ciprofloxacin (CIPRO) as the template molecule, via a noncovalent synthetic procedure. Prior to its use as a sorbent in SPE, the MIP was evaluated chromatographically to confirm that it was indeed molecularly imprinted. The MIP was then used to extract CIPRO selectively from urine samples by means of a two‐step SPE procedure in which a commercial Oasis cartridge and a molecularly imprinted SPE cartridge were combined in series. This approach allowed the matrix compounds present in the samples to be removed effectively. The urine extracts obtained after this two‐step SPE procedure was applied were relatively clean compared to the original samples, and this made it possible to inject directly the extracts into a mass spectrometer and thus quantify CIPRO in urine samples at low levels and reduce the time of analysis.
A pilot study of perceived clinical usefulness of a new computer‐based tool for assessment of visual perception in occupational therapy practice
Authors: Reid Denise T. , Jutai Jeffrey 
Published: May 2006

AbstractA new assessment instrument called the Componential Assessment of Visual Perception (CAVP)© has been developed recently by the authors. It was designed for use in occupational therapy practice, and in other practice areas such as neuropsychology, as a process‐based approach to the evaluation of visual perceptual functioning in children and adults with neurological disorders. In this paper, the CAVP is discussed in terms of its conceptual basis and relevance as an assessment of occupational functioning. In addition, the results of a preliminary study of the clinical usefulness of the CAVP are reported. In this study, a questionnaire designed to measure perceived clinical usefulness of the CAVP was completed by a group of experienced clinicians who routinely assess visual perceptual functioning in clients with neurological disorders. Clinicians were given a standardised demonstration of the CAVP program and a copy of the CAVP's documentation manual. The CAVP software program was installed on to each clinician's computer for a period of two weeks to allow them time to review and analyse it before completing the questionnaire. Overall, promising results regarding the CAVP's potential clinical usefulness were found. Results related to the CAVP's utility, ease of use, format, and appeal are presented, as well as a discussion of the study's limitations. In the final section of this paper, an example of selected CAVP client results is presented to demonstrate how to use it to isolate key processes that are significant in a client's perceptual performance. Copyright © 1997 Whurr Publishers Ltd.
Outer membrane vesicles of the VA‐MENGOC‐BC® vaccine against serogroup B of Neisseria meningitidis: Analysis of protein components by two‐dimensional gel electrophoresis and mass spectrometry
Authors: Uli Liliam , Castellanos‐Serra Lila , Betancourt Lazaro , Domínguez Francisco , Barberá Ramón , Sotolongo Franklin , Guillén Gerardo , Pajón Feyt Rolando 
Published: May 2006

AbstractNeisseria meningitidis is a Gram‐negative bacterium responsible for significant mortality worldwide. While effective polysaccharides‐based vaccines exist against serogroups A, C, W135, and Y, no similar vaccine is suitable for children under 4 years against disease caused by serogroup B strains. Therefore, major vaccine efforts against this serogroup are based on outer membrane vesicles (OMVs), containing major outer membrane proteins. The OMV‐based vaccine produced by the Finlay Institute in Cuba (VA‐MENGOC‐BC®) contributed to the rapid decline of the epidemic in this Caribbean island. While the content of major proteins in this vaccine has been discussed, no detailed work of an outer membrane proteomic map of this, or any other, commercially available OMV‐derived product has been published so far. Since OMVs exhibit a large bias toward a few major proteins and usually contain a high content of lipids, establishing the adequate conditions for high resolution, 2‐DE of this kind of preparation was definitely a technical challenge. In this work, 2‐DE and MS have been used to generate a proteomic map of this product, detailing the presence of 31 different proteins, and it allows the identification of new putative protective protein components it contains.
Comparison of extraction procedures for proteome analysis of Streptococcus pneumoniae and a basic reference map
Authors: Encheva Vesela , Gharbia Saheer E. , Wait Robin , Begum Shajna , Shah Haroun N. 
Published: May 2006

AbstractStreptococcus pneumoniae is an important human pathogen causing life‐threatening invasive diseases such as pneumonia, meningitis and bacteraemia. Despite major advances in our understanding of pneumococcal mechanisms of pathogenicity obtained through genomic studies very little has been achieved on the characterisation of the proteome of this pathogen. The highly complex structure of its cell envelope particularly amongst the various capsular forms enables the cell to resist lysis by conventional mechanical methods. It is therefore highly desirable to develop a cellular lysis and protein solubilisation procedure that minimises protein losses and allows for maximum possible coverage of the proteome of S. pneumoniae. Here we have utilised various combinations of mechanical or enzymatic cell lysis with two protein solubilisation mixtures urea/CHAPS‐based mixture or SDS/DTT‐based mixture in order to achieve best quality protein profiles using two proteomic technologies surface‐enhanced laser desorption ionisation (SELDI) TOF MS and 2‐DE. While urea/CHAPS‐based mixture combined with freeze/thawing provided enough material for good‐quality SELDI TOF MS fingerprints, a combination of mechanical, enzymatic and chemical lysis was needed to be used to successfully extract the desired protein content for 2‐DE analysis. The methods chosen were also assessed for reproducibility and tested on various capsular types of S. pneumoniae. As a result, good‐quality and reproducible profiles were created using various ProteinChip® arrays and more than 800 protein spots were separated on a single 2‐D gel of S. pneumoniae. Twenty‐five of the most abundant protein spots were identified using LC/MS/MS to create a reference map of S. pneumoniae. The proteins identified included glycolytic enzymes such as glyceraldehyde 3‐phosphate dehydrogenase, phosphoglycerate kinase, enolase etc. Several fermentation enzymes were also present including two of the components of the arginine deiminase system. Proteins involved in protein synthesis, such as translation factors and ribosomal proteins, as well as several chaperone proteins were also identified.
Exploring Allium species as a source of potential medicinal agents
Authors: Štajner D. , Milić N. , Čanadanović‐Brunet J. , Kapor A. , Štajner M. , Popović B. M. 
Published: May 2006

AbstractIt has been shown that Allium species may help to prevent tumor promotion, cardiovascular diseases and aging; all processes that are associated with free radicals. Therefore the Allium species of both cultivated species (Allium nutans L., Allium fistulosum L., Allium vineale L., Allium psekemense B. Fedtsch, Allium cepa L., Allium sativum L.) and wild species (Allium flavum L., Allium sphaerocephalum L., Allium atroviolaceum Boiss, Allium schenoprasum L., Allium vineale L., Allium ursinum L., Allium scorodoprasum L.) from various locations were investigated for their antioxidative properties. The leaves were examined for activities of antioxidative enzymes (catalase, peroxidase, superoxide‐dismutase, glutathione‐peroxidase), non‐enzymic antioxidants (reduced glutathione and total flavonoids), content of soluble proteins, vitamin C, carotenoids, chlorophylls a and b, as well as the quantities of malonyldialdehyde and ·OH and O2· – radicals. Using a contemporary spectroscopic fluorescent method, lipofuscin, ‘plant age pigments’ were determined. ESR spectroscopy was used to follow the decrease of oxygen radicals in the presence of extracts of Allium species in phosphate buffer (pH 7). The results showed that all Allium species had strong antioxidative properties due to their high concentration of total flavonoids, high content of carotenoids and chlorophylls, and very low concentrations of toxic oxygen radicals. ESR signals of DMPO‐OH radical adducts, in the presence of Allium extracts in phosphate buffer (pH 7), were reduced by up to 94.3%. Copyright © 2006 John Wiley & Sons, Ltd.
On the N2O correction used for mass spectrometric analysis of atmospheric CO2
Authors: Assonov S. S. , Brenninkmeijer C. A. M. 
Published: May 2006

AbstractTo obtain accurate values of δ13C(CO2) and δ18O(CO2) on environmental CO2 by mass spectrometry, the raw isotope data must be corrected for the isobaric N2O contribution. This is one of the analytical problems limiting inter‐laboratory δ13C(CO2) data consistency. The key parameter, the N2O relative ionisation efficiency (${\rm E}_{{\rm N}_2 {\rm O}}$), cannot be determined with sufficient accuracy by direct measurements of pure N2O. The determination of ${\rm E}_{{\rm N}_2 {\rm O}}$ by analyses on N2OCO2 mixtures of known isotope composition and mixing proportions has been recently suggested. In this work we propose a new method of N2O correction which uses the m/z 30 signal as a measure of the N2O/CO2 ratio, so that determinations of ${\rm E}_{{\rm N}_2 {\rm O}}$ and N2O content are not required. The method uses the fact that fragment‐ion spectra of N2O and CO2 are very specific. The formalism of the correction is considered. Various tests demonstrate that the new method is robust, stable and easy to implement in practice. The effective value $^{30} {\rm R}_{{\rm N}_2 {\rm O}}$ (the key parameter for the new correction) has to be calibrated on known N2OCO2 mixtures by measuring 30R signals only. The method accuracy we presently achieved is around 2.5% and any error which appears to come mostly from our N2OCO2 mixture preparation. Based on our tests and error considerations, the error of the proposed method that may be achieved is as low as ±1.5% (relative to the correction magnitude). For tropospheric CO2 this means ±0.003‰ and ±0.005‰ for δ13C(CO2) and δ18O(CO2), respectively. The proposed method may be valuable for small samples where no separate N2O determinations are available (e.g. ice core samples and CF‐IRMS measurements) as well as for determination of ${\rm E}_{{\rm N}_2 {\rm O}}$ and testing the ‘traditional’ N2O correction based on mass balance calculations. Copyright © 2006 John Wiley & Sons, Ltd.