bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Detection of DNA Melting Curves by Means of Heated Biosensors
Authors: Surkus Annette‐Enrica , Flechsig Gerd‐Uwe 
Published: May 2009

AbstractThis article reports about the detection of DNA melting curves at heated electrochemical biosensors. Osmium tetroxide‐bipyridine‐labeled target oligonucleotides are hybridized with probe oligonucleotides immobilized on gold electrodes. Then, the gold electrode is successively heated in order to measure a complete melting curve consisting of alternating current voltammetric signals. Melting temperatures ϑm, determined at various ionic strengths and in dependence on different numbers of base pair mismatches, have been compared with those obtained by means of UV spectrophotometry. The proposed method holds great promise for the fast and easy parallel detection of nucleic acids sequences on selectively heated electrode arrays. A stringent hybridization temperature can be easily adjusted in order to discriminate base pair mismatches.
Hippocampal shape analysis for Alzheimer's disease using an efficient hypothesis test and regularized discriminative deformation
Authors: Zhou Luping , Lieby Paulette , Barnes Nick , Réglade‐Meslin Chantal , Walker Janine , Cherbuin Nicolas , Hartley Richard 
Published: May 2009

AbstractIn this article, we present a framework to perform statistical shape analysis for segmented hippocampi, including an efficient permutation test for detecting subtle class differences, and a regularized discriminative direction method for visualizing the shape discrepancy. Fisher permutation and bootstrap tests are preferred to traditional hypothesis tests which impose assumptions on the distribution of the samples. In this article, an efficient algorithm is adopted to rapidly perform the exact tests. We extend this algorithm to multivariate data by projecting the shape descriptors onto an informative direction that preserves the original discriminative information as much as possible to generate a scalar test statistic. This informative direction is further used to seek a discriminative direction to isolate the discriminative shape difference between classes from the individual variability. Compared with existing methods, the discriminative direction used in this article is regularized by requiring that the shapes deformed along it respect the underlying shape distribution as well as reflecting the essential shape differences between two populations. Hence, a more accurate localization of difference is produced. We apply our methods to analyze the hippocampal shapes for controls and subjects with Alzheimer's disease from the publicly available OASIS MRI database. We show how to localize the shape differences between the two classes. © 2009 Wiley‐Liss, Inc.
Bioceramic inlays do not improve mechanical incorporation of grit‐blasted titanium stems in the proximal sheep femur
Authors: Keränen Pauli , Koort Jyri , Itälä Ari , Ylänen Heimo , Dalstra Michel , Hupa Mikko , Kommonen Bertel , Aro Hannu T. 
Published: May 2009

AbstractThe aim of the present study was to determine, if bioactive glass (BG) surface inlays improve osseointegration of titanium implants in the proximal femur of adult sheep. In simulation of uncemented primary stems (nine animals), only the proximal part of the implants was grit‐blasted and three surface slots of the grit‐blasted region were filled with sintered BG microspheres. Primary stems were implanted using press‐fit technique. In revision stem simulation (eight animals), grit‐blasting was extended over the whole implant and seven perforating holes of the stem were filled by sintered BG granules. Revision stems were implanted with a mixture of autogenous bone graft and BG granules. Comparison with solid partially or fully grit‐blasted control stems implanted in the contralateral femurs was performed in the primary and revision stem experiments at 12 and 25 weeks, respectively. Implant incorporation was evaluated by torsional failure testing and histomorphometry. Only one‐third of the primary stems anchored mechanically to bone. The revision stems incorporated better and the BG inlays of the revision stems showed ingrowth of new bone. However, there were no significant differences in the torsional failure loads between the stems with BG inlays and the control stems. In conclusion, surface BG inlays gave no measurable advantage in mechanical incorporation of grit‐blasted titanium implants. Overall, the proximal sheep femur, characterized by minimal amount of cancellous bone and the presence of adipocytic bone marrow, seemed to present compromised bone healing conditions. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Bone ingrowth into porous silicon nitride
Authors: Anderson M. C. , Olsen R. 
Published: May 2009

AbstractAchieving solid skeletal attachment is a requirement for the clinical success of orthopedic implants. Porous or roughened surfaces and coatings have been developed and used with mixed success to achieve attachment due to bone ingrowth. Silicon nitride is a high performance ceramic whose strength, imaging properties, and biocompatibility make it a candidate material for orthopedic implants. A porous form of silicon nitride, cancellous‐structured ceramic (CSC), has been developed. CSC is a nonresorbable, partially radiolucent porous structure that can be bonded to orthopedic implants made of silicon nitride to facilitate skeletal attachment. The purpose of this study was to quantify the extent and rate of bone ingrowth into CSC in a large animal model. Cylindrical implants were placed bilaterally using staged surgeries in the medial femoral condyle of six sheep. Condyles were retrieved after 3 and 6 months in situ and prepared for examination of bone growth under SEM. Bone grew into CSC to extents and at rates similar to those reported for other titanium porous surfaces in studies involving large animals and postmortem retrievals in humans. Bone ingrowth was observed at depths of penetration greater than 3 mm in some implants after only 12 weeks in situ. Bone ingrowth into CSC is a viable method for achieving skeletal attachment. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Fragmin/protamine microparticles as cell carriers to enhance viability of adipose‐derived stromal cells and their subsequent effect on in vivo neovascularization
Authors: Nakamura Shingo , Kishimoto Satoko , Nakamura Shin‐ichiro , Nambu Masaki , Fujita Masanori , Tanaka Yoshihiro , Mori Yasutaka , Tagawa Masahiro , Maehara Tadaaki , Ishihara Masayuki 
Published: May 2009

AbstractWe prepared fragmin/protamine microparticles (F/P MPs) as cell carriers to enhance cell viability. Use of material consisting of a low‐molecular‐weight heparin (fragmin) mixed with protamine resulted in water‐insoluble microparticles (about 0.5–1 μm in diameter). In this study, we investigated the capability of F/P MPs to enhance the viabilities of human microvascular endothelial cells (HMVECs), human dermal fibroblasts (fibroblasts), and adipose tissue‐derived stromal cells (ATSCs) in suspension culture. F/P MPs were bound to the surfaces of these cells, and the interaction of these cells with F/P MPs induced cells/F/P MPs‐aggregate formations in vitro, and maintained viabilities of those cells for at least 3 days. The ATSCs/F/P MPs‐aggregates adhered to and grew on suspension culture plates in a fashion similar to those on type I collagen‐coated plates. The cultured ATSCs secreted significant amounts of angiogenic heparin‐binding growth factors such as FGF‐2. When the ATSCs/F/P MPs‐aggregates were subcutaneously injected into the back of nude mice, significant neovascularization and fibrous tissue formation were induced near the site of injection from day 3 to week 2. The ATSCs/F/P MPs‐aggregates were thus useful and convenient biomaterials for cell‐therapy of angiogenesis. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
In vitro biocompatibility evaluation of surface‐modified titanium alloys
Authors: Treves Cristina , Martinesi Maria , Stio Maria , Gutiérrez Alejandro , Jiménez José Antonio , López María Francisca 
Published: May 2009

AbstractThe present work is aimed to evaluate the effects of a surface modification process on the biocompatibility of three vanadium‐free titanium alloys with biomedical applications interest. Chemical composition of alloys investigated, in weight %, were Ti‐7Nb‐6Al, Ti‐13Nb‐13Zr, and Ti‐15Zr‐4Nb. An easy and economic method intended to improve the biocompatibiblity of these materials consists in a simple thermal treatment at high temperature, 750°C, in air for different times. The significance of modification of the surface properties to the biological response was studied putting in contact both untreated and thermally treated alloys with human cells in culture, Human Umbilical Vein Endothelial Cells (HUVEC) and Human Peripheral Blood Mononuclear Cells (PBMC). The TNF‐α release data indicate that thermal treatment improves the biological response of the alloys. The notable enhancement of the surface roughness upon oxidation could be related with the observed reduction of the TNF‐α levels for treated alloys. A different behavior of the two cell lines may be observed, when adhesion molecules (ICAM‐1 and VCAM‐1 in HUVEC, ICAM‐1, and LFA‐1 in PBMC) were determined, PBMC being more sensitive than HUVEC to the contact with the samples. The data also distinguish surface composition and corrosion resistance as significant parameters for the biological response. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Melatonin and its brain metabolite N1‐acetyl‐5‐methoxykynuramine prevent mitochondrial nitric oxide synthase induction in parkinsonian mice
Authors: Tapias Víctor , Escames Germaine , López Luis C. , López Ana , Camacho Encarnación , Carrión María D. , Entrena Antonio , Gallo Miguel A. , Espinosa Antonio , Acuña‐Castroviejo Darío 
Published: May 2009

AbstractMelatonin prevents mitochondrial failure in models of sepsis through its ability to inhibit the expression and activity of both cytosolic (iNOS) and mitochondrial (i‐mtNOS) inducible nitric oxide synthases. Because Parkinson's disease (PD), like sepsis, is associated with iNOS induction, we assessed the existence of changes in iNOS/i‐mtNOS and their relation with mitochondrial dysfunction in the MPTP model of PD, which also displays increased iNOS expression. We also evaluated the role of melatonin (aMT) and its brain metabolite, N1‐acetyl‐5‐methoxykynuramine (AMK), in preventing i‐mtNOS induction and mitochondrial failure in this model of PD. Mitochondria from substantia nigra (SN) and, to a lesser extent, from striatum (ST) showed a significant increase in i‐mtNOS activity, nitrite levels, oxidative stress, and complex I inhibition after MPTP treatment. MPTP‐induced i‐mtNOS was probably related to mitochondrial failure, because its prevention by aMT and AMK reduced oxidative/nitrosative stress and restored complex I activity. These findings represent the first experimental evidence of a potential role for i‐mtNOS in the mitochondrial failure of PD and support a novel mechanism in the neuroprotective effects of aMT and AMK. © 2009 Wiley‐Liss, Inc.
Non‐negative Matrix Factorization for the identification of patterns of atmospheric pressure and geopotential for the Northern Hemisphere
Authors: Schlink Uwe , Thiem Alexander 
Published: May 2009

AbstractAs the atmospheric system is characterized by highly complex interactions between a large number of physical variables, it is a challenging task for researchers to break up the complicated structures into a few significant modes of variability.An innovative technique, called Non‐negative Matrix Factorization (NMF), developed to provide a reduced‐dimensional representation of large‐scale non‐negative data and to extract underlying features, is introduced as a tool for meteorological applications. The method is used to decompose space‐time meteorological fields into spatial patterns and associated time indices in order to advance our knowledge of dominant atmospheric processes. For the Northern Hemisphere the 500 hPa geopotential field together with sea level pressure (SLP) are analysed using an up‐to‐date NMF algorithm as well as a helpful method of NMF initialization based on Singular Value Decomposition (SVD). Several NMF patterns correspond to the variations identified by traditional EOF analysis, such as the East Atlantic and the Pacific/North American Pattern. For the North Atlantic Oscillation the NMF identifies sub‐patterns: The positive phase is associated with systems of pressure variation over the Pacific Ocean and the Arctic, respectively, the negative phase resembles the EOF pattern.As the NMF patterns not only represent variability, like EOF patterns, but also are fractions of the total observed values, we demonstrate for a location near Nikolski, Alaska, the temporal development of the geopotential as a superposition of NMF‐factors. Copyright © 2009 Royal Meteorological Society
A modified support vector machine based prediction model on streamflow at the Shihmen Reservoir, Taiwan
Authors: Li Pei‐Hao , Kwon Hyun‐Han , Sun Liqiang , Lall Upmanu , Kao Jehng‐Jung 
Published: May 2009

AbstractThe uncertainty of the availability of water resources during the boreal winter has led to significant economic losses in recent years in Taiwan. A modified support vector machine (SVM) based prediction framework is thus proposed to improve the predictability of the inflow to Shihmen reservoir in December and January, using climate data from the prior period. Highly correlated climate precursors are first identified and adopted to predict water availability in North Taiwan. A genetic algorithm based parameter determination procedure is implemented to the SVM parameters to learn the non‐linear pattern underlying climate systems more flexibly. Bagging is then applied to construct various SVM models to reduce the variance in the prediction by the median of forecasts from the constructed models. The enhanced prediction ability of the proposed modified SVM‐based model with respect to a bagged multiple linear regression (MLR), simple SVM, and simple MLR model is also demonstrated. The results show that the proposed modified SVM‐based model outperforms the prediction ability of the other models in all of the adopted evaluation scores. Copyright © 2009 Royal Meteorological Society
Repopulation of vascularized bone allotransplants with recipient‐derived cells: Detection by laser capture microdissection and real‐time PCR
Authors: Pelzer Michael , Larsen Mikko , Friedrich Patricia F. , Aleff Ross A. , Bishop Allen T. 
Published: May 2009

AbstractMechanisms underlying successful composite tissue transplantation must include an analysis of transplant chimerism, which is little studied, particularly in calcified tissue. We have developed a new method enabling determination of lineage of selected cells in our model of vascularized bone allotransplantation. Vascularized femoral allotransplantation was performed from female Dark Agouti (DA) donor rats to male Piebald Virol Glaxo (PVG) recipients, representing a major histocompatibility mismatch. Four groups differed in use of immunosuppression (±2 weeks Tacrolimus) and surgical revascularization, by implantation of either a patent or a ligated saphenous arteriovenous (AV) bundle. Results were assessed at 18 weeks. Bone blood flow was measured by the hydrogen washout technique and transverse specimens were prepared for histology. Real‐time PCR was performed on DNA from laser capture microdissected cortical bone regions to determine the extent of chimerism. To do so, we analyzed the relative expression ratio of the sex‐determining region Y (Sry) gene, specific only for recipient male rat DNA, to the cyclophilin housekeeper gene. Substantial transplant chimerism was seen in cortical bone of all groups (range 77–97%). Rats without immunosuppression and with a patent AV bundle revealed significantly higher chimerism than those with immunosuppression and a ligated AV bundle, which maintained transplant cell viability. We describe a new method to study the extent of chimerism in rat vascularized bone allotransplants, including a sex‐mismatched transplantation model, laser capture microdissection of selected bone regions, and calculation of the relative expression ratio. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1514–1520, 2009
Nomographic estimation and evaluation of soil erodibility under simulated and natural rainfall conditions
Authors: Singh M. J. , Khera K. L. 
Published: May 2009

AbstractTo evaluate soil erodibility under different land uses and to study the applicability of nomograph for estimation of soil erodibility a field experiment was conducted under both natural and simulated rainfall conditions under four land uses viz. barren, cultivated, grassland, and forest in the sub‐mountainous tract of Punjab (India). Measured soil erodibility (K) values varied from 0·33 to 0·67 under natural rainfall conditions and from 0·23 to 0·40 under simulated rainfall conditions. Among different land uses, measured K was in the order of barren > cultivated > grassland > forest soils. The values of the K estimated by nomograph were very low as compared to the observed values. The trends were also in contrast to these observed values of K under simulated and natural rainfall conditions. To modify nomograph equation, different ranges of aggregate sizes were correlated with soil loss. It was observed that water stable aggregates (WSA) <2 mm size had a significant correlation with soil loss under both natural (r = 0·88) and simulated (r = 0·76) rainfall conditions. So the nomograph equation was modified to include the M parameter based on WSA <2 mm size. The value of K estimated from the modified nomograph had a significant correlation with measured values of K under both the natural and simulated rainfall conditions. Copyright © 2009 John Wiley & Sons, Ltd.
4‐Alkylphenoxymethyl‐Substituted Polystyrenes for Liquid Crystal Alignment Layers
Authors: Kang Hyo , Kim Tae‐Ho , Kang Daeseung , Lee Jong‐Chan 
Published: May 2009

AbstractWe synthesized a phenoxymethyl‐substituted polystyrene (PHP) and a series of 4‐alkylphenoxymethyl‐substituted polystyrenes, where the alkyl group is (CH2)nH (n = 1, 2, 4, 6, and 8), using polymer analogous reactions, in order to study the effect of the phenoxymethyl and 4‐alkylphenoxymethyl side groups on the liquid crystal (LC) alignment properties. The LC cell fabricated with the rubbed PHP film exhibited homogeneous planar and perpendicular LC alignment with respect to the rubbing direction. On the contrary, the LC cells made from the 4‐alkylphenoxymethyl‐substituted polystyrenes showed homeotropic LC alignment behaviors even at a very high rubbing density of 250, regardless of the length of the alkyl groups. Previously, n‐alkylsulfonylmethyl‐substituted polystyrenes with alkyl groups having more than 8 carbons (n > 8) showed homeotropic LC alignment behavior. Therefore, the additional phenoxy group in the side chain was found to improve the homeotropic LC aligning ability of the polystyrene derivatives.magnified image
On The Micro‐Phase Separation in Waterborne Polyurethanes
Authors: Princi Elisabetta , Vicini Silvia , Castro Kepa , Capitani Donatella , Proietti Noemi , Mannina Luisa 
Published: May 2009

AbstractSome polyester and polycarbonate‐based waterborne polyurethanes (WPU) were characterised by means of several techniques, to correlate the morphology with their structures and properties. The morphological analysis carried out by transmission electron microscopy on thin sections showed that the selected polyurethanes, after purification, exhibit a nanostructured phase separation between hard and soft domains. The presence of hydrogen bonding and the hard/soft ratio were evaluated by FT IR and NMR spectroscopy. Both the thermal and the dynamic mechanical analysis allowed the polymers microstructure to be correlated with the polymer properties; two glass transition temperatures were determined, corresponding to the hard and soft domains respectively.magnified image
Stereocomplex Crystallization and Spherulite Growth of Low Molecular Weight Poly(L‐lactide) and Poly(D‐lactide) from the Melt
Authors: Bouapao Leevameng , Tsuji Hideto 
Published: May 2009

AbstractIn isothermal crystallization from the melt, only stereocomplex crystallites as a crystalline species were formed in all the blends at crystallization temperature above 130 °C. The spherulite growth rate and crystallinity values decreased monotonically with deviation of the PDLA content from 50%. Surprisingly, regime analysis revealed that the crystallization mechanism of the blends was independent of PDLA content. In non‐isothermal crystallization of melt‐quenched specimens during heating, the cold crystallization of blends takes place rapidly at a lower temperature compared to that of pure PLLA and PDLA. This is attributable to the rapid stereocomplex crystallization or the nucleating effect of stereocomplex crystallites formed during quenching from the melt or second heating.magnified image
Effect of glycosidation of isoflavones on their bioavailability and pharmacokinetics in aged male rats
Authors: Sepehr Estatira , Cooke Gerard M. , Robertson Patrick , Gilani G. Sarwar 
Published: May 2009

AbstractThere are limited reports on the bioavailability and pharmacokinetics of isoflavones in elderly humans and aged animals. The present study was conducted to assess the effect of glycosidation of isoflavones on their bioavailability and pharmacokinetics in aged (20 month old) male Fischer‐344 (F‐344) rats. The F‐344 rat, developed by the National Institute on Aging, is an inbred rat model that is commonly used for aging studies and resembles many features of aging humans. Three sources of isoflavones; NovasoyTM(a commercial supplement), a mixture of synthetic aglycons (daidzein, genistein and glycitein), and a mixture of synthetic glucosides (daidzin, genistin, and glycitin) were tested. Following administration, blood samples were collected at different times (0–48 h post‐oral gavage and 0–8 h post‐IV dosing). Plasma isoflavones and 7‐hydroxy‐3‐(4′‐hydroxyphenyl)‐chroman (a metabolite of daidzein) were measured by LC/MS. The extent of absorption was determined by comparing the area under the curve (AUC) of the plasma‐concentration time curve after intravenous (IV) administration with that following oral administration. The extent of bioavailability was then calculated as: %bioabailability = (AUCor/AUCIV)×(DoseIV/Doseor)×100. Bioavailabilities for genistein were significantly (p= 0.013) higher for the aglycon (35 ± 9%) compared with the glucoside forms (11 ± 3%). In contrast, the bioavailabilities for glycitein were significantly (p= 0.011) higher in Novasoy (27 ± 13%) and the glucoside form (21 ± 10%) compared with the aglycon (8 ± 3%). No significant differences in the bioavailability of daidzein were observed in aged rats dosed with aglycon, glucoside or Novasoy. However, aged rats were able to produce equol as early as 8 h post‐dosing. In summary, the source of isoflavones had significant effects on genistein and glycitein bioavailability in aged male rats.