bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conformational Analysis of MαNP Esters, Powerful Chiral Resolution and 1H NMR Anisotropy Tools – Aromatic Geometry and Solvent Effects on Δδ Values
Authors: Kasai Yusuke , Sugio Akinori , Sekiguchi Satoshi , Kuwahara Shunsuke , Matsumoto Takatoshi , Watanabe Masataka , Ichikawa Akio , Harada Nobuyuki 
Published: January 2007

AbstractThe MαNP acid method is very powerful for the preparation of enantiopure alcohols by resolution and the simultaneous determination of their absolute configurations by the 1H NMR anisotropy effect, where the syn‐syn conformation is taken as the preferred conformation of MαNP esters. However, the syn‐syn conformation of MαNP esters looks unstable, because two electronegative oxygen atoms (CH3O and C=O) are close to each other. To solve the problem of why the MαNP esters take such a syn‐syn conformation, the aromatic geometry and solvent effects on the 1H NMR anisotropy data were studied, leading to the following conclusions: i) the hydrogen‐bonding‐like interaction among the H‐8′ of the naphthyl group, the ester carbonyl oxygen, and the methoxy oxygen supports a triangular intramolecular force to stabilize the syn‐syn conformation; ii) triangular hydrogen bonding among a hydrogen atom of protic solvents, the ester carbonyl oxygen, and the methoxy oxygen also supports the syn‐syn conformation. This hydrogen bonding, as the solvation effect implies, suggests that a similar hydrogen bonding between a MαNP ester and a hydroxy group of the silica gel surface would make a dominant contribution to the excellent discrimination of diastereomeric MαNP esters observed in the HPLC on silica gel.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Carbocyclic Analog of the Oxidatively Generated DNA Lesion Spiroiminodihydantoin
Authors: Müller Heiko , Carell Thomas 
Published: January 2007

Abstract8‐Oxo‐7,8‐dihydro‐2′‐deoxyguanosine (8‐oxo‐dG) is a mutagenic DNA lesion which is prone to further oxidation. One‐electron oxidants like IrIV oxidize 8‐oxo‐dG to give secondary lesions such as the spiroiminodihydantoin. This lesion blocks DNA polymerases and induces G → T as well as G → C transversions. Here, we report the synthesis of a carbocyclic analog of the 8‐oxo‐dG lesion and the carbocyclic version of the spiroiminodihydantoin lesion. Both lesion analogs were obtained within single‐stranded DNA and as their corresponding nucleosides. Characterization of the lesion analogs was achieved by HPLC, ESI‐MS and ESI‐MS/MS, as well as enzymatic digestion of the oligonucleotides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Dual‐opposite‐injection CZE: Theoretical aspects and application to organic and pharmaceutical compounds
Authors: Weekley Brian S. , Foley Joe P. 
Published: January 2007

AbstractSeveral important figures of merit (migration time, efficiency, resolution, resolution per unit time, and electrophoretic selectivity) are quantitatively compared for the first time for conventional CZE and dual‐opposite‐injection CZE (DOI‐CZE). Aspects of DOI‐CZE relevant to the separation of organic and pharmaceutical ions (MW>120 Da) are also discussed. Two new approaches to resolve the codetection of anions and cations, hydrodynamic flow‐modified DOI‐CZE and polarity reversal in combination with asymmetric detector window positioning, are compared with the method of preliminary transport, a variable procedure within sequential sample introduction, using a six‐component sample of organic and pharmaceutical compounds. The advantages of DOI‐CZE for the simultaneous analysis of organic/pharmaceutical anions and cations are illustrated in a direct comparison of conventional CZE and DOI‐CZE for the separation of a ten‐component mixture of pharmaceutical ions (five ionized acids and five ionized bases).
Fluid dynamics in capillary and chip electrochromatography
Authors: Nischang Ivo , Tallarek Ulrich 
Published: January 2007

AbstractThis review is concerned with the phenomenological fluid dynamics in capillary and chip electrochromatography (EC) using high‐surface‐area random porous media as stationary phases. Specifically, the pore space morphology of packed beds and monoliths is analyzed with respect to the nonuniformity of local and macroscopic EOF, as well as the achievable separation efficiency. It is first pointed out that the pore‐level velocity profile of EOF through packed beds and monoliths is generally nonuniform. This contrasts with the plug‐like EOF profile in a single homogeneous channel and is caused by a nonuniform distribution of the local electrical field strength in porous media due to the continuously converging and diverging pores. Wall effects of geometrical and electrokinetic nature form another origin for EOF nonuniformities in packed beds which are caused by packing hard particles against a hard wall with different zeta potential. The influence of the resulting, systematic porosity fluctuations close to the confining wall over a distance of a few particle diameters becomes aggravated at low column‐to‐particle diameter ratio. Due to the hierarchical structure of the pore space in packed beds and silica‐based monoliths which are characterized by discrete intraparticle (intraskeleton) mesoporous and interparticle (interskeleton) macroporous spatial domains, charge‐selective transport prevails within the porous particles and the monolith skeleton under most general conditions. It forms the basis for electrical field‐induced concentration polarization (CP). Simultaneously, a finite and – depending on morphology – often significant perfusive EOF is realized in these hierarchically structured materials. The data collected in this review show that the existence of CP and its relative intensity compared to perfusive EOF form fundamental ingredients which tune the fluid dynamics in EC employing monoliths and packed beds as stationary phases. This addresses the (electro)hydrodynamics, associated hydrodynamic dispersion, as well as the migration and retention of charged analytes.
Modelling of fluid–structure interactions with the space–time finite elements: Solution techniques
Authors: Tezduyar Tayfun E. , Sathe Sunil 
Published: January 2007

AbstractThe space–time fluid–structure interaction (FSI) techniques developed by the Team for Advanced Flow Simulation and Modeling (T★AFSM) have been applied to a wide range of 3D computation of FSI problems, some as early as in 1994 and many with challenging complexities. In this paper, we review these space–time FSI techniques and describe the enhancements introduced recently by the T★AFSM to increase the scope, accuracy, robustness and efficiency of these techniques. The aspects of the FSI solution process enhanced include the deforming‐spatial‐domain/stabilized space–time (DSD/SST) formulation, the fluid–structure interface conditions, the preconditioning techniques used in iterative solution of the linear equation systems, and a contact algorithm protecting the quality of the fluid mechanics mesh between the structural surfaces coming into contact. We present a number of 3D numerical examples computed with these new stabilized space–time FSI (SSTFSI) techniques. Copyright © 2007 John Wiley & Sons, Ltd.
Association of CD44 V3‐containing isoforms with tumor cell growth, migration, matrix metalloproteinase expression, and lymph node metastasis in head and neck cancer
Authors: Wang Steven J. , Wreesmann Volkert B. , Bourguignon Lilly Y. W. 
Published: January 2007

AbstractBackground.The CD44 family of receptors includes multiple variant isoforms, some of which have been linked to tumor progression. The objective of this study was to investigate whether CD44 v3‐containing isoforms are involved in head and neck squamous cell carcinoma (HNSCC) tumor progression.Methods.Laboratory investigation utilizing HNSCC cell lines and clinical tissue specimens was performed.Results.Investigation of 13 HNSCC cell lines revealed a diversity of CD44 isoform profiles, including expression of CD44 v3‐containing isoforms. Two cell lines, HOC313 and MDA1483, were selected for further study based on their CD44 v3 expression profile. The HOC313 cell line, which highly expresses CD44 v3‐containing isoforms, demonstrated hyaluronan‐mediated CD44‐dependent promotion of tumor cell growth and migration. Conditioned media from the HOC313 cell line also exhibited high matrix metalloproteinase expression on gelatin zymography. Immunohistochemical analysis of a series of metastatic HNSCC lymph nodes revealed CD44 overexpression as well as staining for CD44 v3‐containing isoforms.Conclusion.CD44 v3‐containing isoforms are associated with HNSCC growth, migration, and matrix metalloproteinase activity and can be identified in lymph node metastasis. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Myopericytoma of the oral cavity
Authors: Datta Vivekanand , Rawal Yeshwant B. , Mincer Harry H. , Anderson Mark K. 
Published: January 2007

AbstractBackground.Myopericytoma is a rare mesenchymal neoplasm of pericytic cells demonstrating myoid differentiation. The lesion typically arises within the subcutaneous tissue of the extremities. We report a case that, to the best of our knowledge, is the first case of myopericytoma involving the soft tissue of the oral cavity.Methods.A 36‐year‐old woman had a 5‐mm sessile, whitish‐pink, firm tongue nodule. The patient underwent excisional biopsy, and histopathologic examination as well as immunohistochemical analysis were performed.Results.The differential diagnosis by histologic analysis included solitary fibrous tumor, myofibroma, glomus tumor, and myopericytoma. The results of immunohistochemical analysis, when combined with the histologic features, led to a diagnosis of myopericytoma.Conclusions.Applying strict morphologic criteria and appropriately selective immunohistochemical markers will help to distinguish myopericytoma in the oral cavity. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Clinical significance of MMP‐2 and MMP‐9 in patients with oral cancer
Authors: Patel Beena P. , Shah Shakuntala V. , Shukla Shilin N. , Shah Pankaj M. , Patel Prabhudas S. 
Published: January 2007

AbstractBackground.Factors that represent the potential for invasion and metastasis, such as matrix metalloproteinases (MMPs), could predict prognosis of cancer. Therefore, the authors studied plasma and tissue levels of MMP‐2 and MMP‐9 in oral cancer, the leading malignancy in India.Methods.Enzyme‐linked immunosorbent assay and gelatin zymography were used for the MMP analysis from plasma and tissue samples, respectively.Results.Latent, active, and total forms and activation ratio of MMP‐2 and MMP‐9 were significantly elevated in malignant tissues as compared with adjacent normal tissues. Activation of MMP‐2 was higher than MMP‐9 in malignant tissues. Activation ratio was significantly higher in malignant tissues of the patients with lymph node metastasis as compared with those without lymph node metastasis (p = .005). Plasma MMP‐9 levels were significantly lower in responders as compared with pretreatment levels (p = .002).Conclusion.The data indicate that MMP‐2 and MMP‐9 can be useful to identify metastatic phenotype as well as for treatment monitoring in oral cancer. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Ecological and environmental instream flow requirements for the Wei River—the largest tributary of the Yellow River
Authors: Song J. X. , Xu Z. X. , Liu C. M. , Li H. E. 
Published: January 2007

AbstractInstream flows are essential determinants of channel morphology, riparian and aquatic flora and fauna, water quality estuarine inflow and stream load transport. The ecological and environmental instream flow requirements (EEIFR) should be estimated to make the exploitation and utilization of water resources in a highly efficient and sustainable way and maintain the river ecosystem good health. As the largest tributary of the Yellow River, the Wei River is the ‘Mother River’ of Guanzhong region in Shaanxi province. It plays a great role in the development of West China and the health of the ecosystem of the Yellow River. The objective of this study is to estimate the EEIFR for improving the Wei River's ecological and environmental condition and develop the river healthily. Concerning the main ecological and environmental functions of the Wei River in Shaanxi Province, the EEIFR for each section of the Wei River including minimum instream flow requirements (IFR) for aquicolous biotopes maintenance, IFR for channel seepage, channel evaporation, stream self‐purification and sediment transportation were estimated in this paper. The methods to estimate the instream flow requirements for stream self‐purification and instream flow requirements for sediment transportation were proposed. The temporal scale of typical years include the year with the probability 25% of occurrence (high‐flow year), the year with the probability 50% (normal‐flow year) and the year with the probability 75% (low‐flow year). The results show that the EEIFR for the Wei River mainly include instream flow requirements for self‐purification and sediment transportation in each typical year. From high‐flow year to low‐flow year, the annual EEIFR for each reach decrease, except those for the reach from Linjiacun to Weijiabao, and from Linjiacun at the upper reaches to Huaxian at the lower reaches, and the annual reach EEIFR decrease in a sequence. Copyright © 2007 John Wiley & Sons, Ltd.
Laser surface treatment of hydroxyapatite for enhanced tissue integration: Surface characterization and osteoblastic interaction studies
Authors: Teixeira S. , Monteiro F. J. , Ferraz M. P. , Vilar R. , Eugénio S. 
Published: January 2007

AbstractBiocompatibility has long been associated with surface microtopography, microtexture, and microchemistry. The surface topography eventually affects the nature and the intensity of the interactions that occur at biomaterial–biological interface (cell adhesion, mobility, spreading, and proliferation). Therefore, it is necessary to produce and work with controlled microtopographical surfaces that present reproducible microdomains of a dimension similar to that of the biological elements of interest (in this case, osteoblasts). There are a number of substrates that already have been studied in terms of surface topography; however, few studies are related to hydroxyapatite (HA) substrates. As it is well established, HA is a well‐known ceramic that is extremely used in medical applications, namely implants and coatings. In this work, the surface topography of dense HA substrates was altered by using KFr excimer laser. The surface was characterized by atomic force microscopy and contact angle measurements, while the cell distribution and morphology was assessed by scanning electron microscopy and confocal laser scanning microscopy. Results revealed that the surface is characterized by a homogeneous columnar structure with high specific area. Moreover, cells were able to attach and spread on the surface of the samples, and gradually grow into nearly confluent monolayers. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
In vitro platelet adhesion on polymeric surfaces with varying fluxes of continuous nitric oxide release
Authors: Wu Yiduo , Zhou Zhengrong , Meyerhoff Mark E. 
Published: January 2007

AbstractNitric oxide (NO) is released by endothelial cells that line the inner walls of healthy blood vessels at fluxes ranging from 0.5 × 10−10 to 4.0 × 10−10 mol cm−2 min−1, and this continuous NO release contributes to the extraordinary thromboresistance of the intact endothelium. To improve the biocompatibility of blood‐contacting devices, a biomimetic approach to release/generate NO at polymer/blood interfaces has been pursued recently (with NO donors or NO generating catalysts doped within polymeric coatings) and this concept has been shown to be effective in preventing platelet adhesion/activation via several in vivo animal studies. However, there are no reports to date describing any quantitative in vitro assay to evaluate the blood compatibilities of such NO release/generating polymers with controlled NO fluxes. Such a methodology is desired to provide a preliminary assessment of any new NO‐releasing material, in terms of the effectiveness of given NO fluxes and NO donor amounts on platelet activity before the more complex and costly in vivo testing is carried out. In this article, we report the use of a lactate dehydrogenase assay to study in vitro platelet adhesion on such NO‐releasing polymer surfaces with varying NO fluxes. Reduced platelet adhesion was found to correlate with increasing NO fluxes. The highest NO flux tested, 7.05 (±0.25) × 10−10 mol cm−2 min−1, effectively reduced platelet adhesion to nearly 20% of its original level (from 14.0 (±2.1) × 105 cells cm−2 to 2.96 (±0.18) × 105 cells cm−2) compared to the control polymer coating without NO release capability. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
In vivo evaluation of a porous hydroxyapatite/poly‐DL‐lactide composite for bone tissue engineering
Authors: Hasegawa Shin , Neo Masashi , Tamura Jiro , Fujibayashi Shunsuke , Takemoto Mitsuru , Shikinami Yasuo , Okazaki Kenshi , Nakamura Takashi 
Published: January 2007

AbstractAs reported previously, a porous composite of uncalcined hydroxyapatite (u‐HA) and poly‐DL‐lactide (PDLLA) showed excellent osteoconductivity and biodegradability as a bone substitute in rabbit model. In this study, to investigate the usefulness of this composite as a scaffold loaded with cells, we estimated whether this material showed osteogenesis on implantation to extraosseous site. On loading with syngeneic bone marrow cells and implantation into rat dorsal subcutaneous tissue, osteogenesis with enchondral ossification was seen both on and in the material at 3 weeks after implantation. The osteogenesis in the u‐HA/PDLLA had progressed, and newly formed bone tissue was found in the material by 6 weeks. To investigate the osteoinductive properties of the material, we implanted this porous composite material into extraosseous canine dorsal muscle. At 8 weeks, osteogenesis was seen in the pores of the material. Newly formed bone could be observed adjacent to the material. In addition, cuboidal osteoblasts adjacent to the newly formed bone were evident. Neither cartilage nor chondrocytes were found. These results might indicate that the material induced osteogenesis by intramembranous ossification. Conversely, similar porous PDLLA did not induce osteogenesis during the observation period. Therefore, porous HA/PDLLA, which has osteoconductive and osteoinductive properties, might be a useful material for use as a bone substitute and cellular scaffold. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Mechanical properties of open‐pore titanium foam
Authors: Imwinkelried Thomas 
Published: January 2007

AbstractOpen‐pore titanium foams are produced using the so‐called space holder method. The mechanical properties of titanium foams with porosities of 50–80% are studied. The stiffness and yield strength of the foams are found to encompass the property range between cancellous bone and cortical bone. The analyzed foams are found to be anisotropic due to the use of nonspherical space holder particles which rearrange during the compaction of the powder mixture. The titanium foams are stronger perpendicular to the compaction direction and weaker along the compaction axis. In view of the application as an implant material in the lumbar spine, an intermediate porosity of 60–65% is analyzed more in detail. The typical yield strength of titanium foam with 62.5% porosity is above 60MPa in compression, bending, and tension. Stiffness values vary with the testing method from 7–14 GPa. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
The impact of polyglycolide membrane on a tendon after surgical rejoining. A histological and histomorphometric analysis in rabbits
Authors: Pihlajamäki Harri , Tynninen Olli , Karjalainen Pertti , Rokkanen Pentti 
Published: January 2007

AbstractTissue response to self‐reinforced polyglycolide (SR‐PGA) membranes surrounding rejoined rabbit tendons was compared with tissue response to nonenveloped rejoined tendons, with special focus on scar formation and SR‐PGA membrane biodegradation process. Both hind legs of 20 skeletally mature rabbits were operated on by transecting the plantaris longus tendons and rejoining the ends with sutures. The right side seams were enveloped with bioabsorbable SR‐PGA membranes, while the left sides served as noncovered controls. The follow‐up times were 3, 6, 12, and 24 weeks. Scar formation and tissue response to membranes were studied by histological and histomorphometric analysis. Tendon regeneration was most active at 3 weeks. Capillary formation was more prominent in specimens with shorter follow‐up times. Membrane degradation induced an inflammatory reaction observed at all follow‐up time points. Under polarizing microscopy, birefringent SR‐PGA material was seen to vanish almost completely by 24 weeks. SR‐PGA membranes had no specific effect on scar formation and there were no differences in the reunion process of the transected tendon ends between the SR‐PGA membrane groups and the controls. Inflammatory cells in the SR‐PGA membrane groups reflected a tissue reaction to the membrane. When placed in soft tissues, SR‐PGA membranes degraded almost completely within 24 weeks. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Simvastatin and atorvastatin enhance gene expression of collagen type 1 and osteocalcin in primary human osteoblasts and MG‐63 cultures
Authors: Ruiz‐Gaspa Silvia , Nogues Xavier , Enjuanes Anna , Monllau Joan C. , Blanch Josep , Carreras Ramon , Mellibovsky Leonardo , Grinberg Daniel , Balcells Susana , Díez‐Perez Adolfo , Pedro‐Botet Juan 
Published: January 2007

AbstractTo clarify the mechanism of the stimulatory effect of statins on bone formation, we have assessed the effect of simvastatin and atorvastatin on osteoblast activity by analysing cell proliferation, as well as collagen, osteocalcin, and bone morphogenetic protein‐2 (BMP2) gene expression in primary human osteoblast (hOB) and MG‐63 cell line cultures. Explants of bone from patients without any metabolic disease under orthopedic hip procedures were used to obtain hOB. Cell cultures were established, synchronized, and different concentrations of simvastatin or atorvastatin were added (10−9 M, 10−8 M, 10−7 M, 10−6 M) during the experiment. Cell proliferation was analyzed after 24 h. Collagen polypeptide α1 type 1 (COL1A1) gene expression, osteocalcin, and BMP2 expression levels were quantified by real‐time PCR after 24 h incubation with statins. There was a statistically significant decrease in cell proliferation related to simvastatin or atorvastatin addition at all concentrations in primary hOB compared with those not treated. A significant increase in COL1A1, osteocalcin, and BMP2 gene expression was detected when hOB cultures were treated with simvastatin or atorvastatin at different concentrations. Similar but less significant effects were found on MG‐63 cells. After statin treatment we observed both an arrest of proliferation in hOB cells and an increase in collagen, osteocalcin, and BMP2 gene expression, consistent with a stimulatory effect towards mature osteoblast differentiation. These findings support the bone‐forming effect of statins, probably through the BMP2 pathway. J. Cell. Biochem. 101: 1430–1438, 2007. © 2007 Wiley‐Liss, Inc.