bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drainage outflow in different pipe‐drainage variants on gleyic podzoluvisol in the Sava River Valley
Authors: Petošić D. , Tadić L. , Romić D. , Tomić F. 
Published: January 2004

AbstractFive‐year investigations (1995–99) were carried out on the experimental drainage field “Jelenscak”, Kutina, in Croatia. The field is situated in the Sava River valley, on gleyic podzoluvisol. The trial involved eight pipe‐drainage variants, differing in drainpipe spacing and backfilling. Drainpipe spacings of 15, 20, 25 and 30 m with gravel backfill and spacings of 10, 15, 20 and 25 m without gravel backfill were tested. The shortest duration of drainage outflow was recorded in the variant with a drainpipe spacing of 15 m with gravel backfill and in the variant with a drainpipe spacing of 10 m without gravel backfill. These values are significantly different (P<0.01) compared to the values obtained in other variants. Average monthly drainage outflows in the said two drainage variants are also significantly higher compared to the other test variants (P<0.01). The outflow peak in the studied variants ranged from 12.3 mm d−1 up to 64.9 mm d−1. Drainage outflows during the four‐year period (1996–99), calculated using the numerical model SWAP‐93, were confirmed by direct measurements on the trial field with 95.8% precision. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluations of bioactivity and mechanical properties of poly (ε‐caprolactone)/silica nanocomposite following heat treatment
Authors: Yoo Jeong Joon , Rhee Sang‐Hoon 
Published: January 2004

AbstractA composite material consisting of poly(ε‐caprolactone) (PCL) and silica was prepared and evaluated as a bioactive bone substitute. The composite was synthesized by the co‐condensation of tetraethyl orthosilicate and PCL and end‐capped with triethoxysilane (Si‐PCL). The as‐prepared specimens were subjected to an initial heat treatment of 2 days at 60°C, followed by further heat‐treatments at 100°C, 150°C, and 200°C for 24 h. The tensile mechanical properties of the heat‐treated specimens were determined, and additional specimens were exposed to a simulated body fluid (SBF) for different periods of time. The SBF exposure led to the deposition of a layer of apatite crystals on the surface of the composites. It was found that increasing the second heat‐treatment temperature produced an increase in tensile strength and Young's modulus of the composite but a decrease in the initial rate of apatite formation. These phenomena are explained in terms of the condensation reaction that takes place between the silanol groups in the silica and Si‐PCL as the heat‐treatment temperature is increased. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 401–410, 2004
Evaluation of biocompatibility of polypyrrole in vitro and in vivo
Authors: Wang Xioadong , Gu Xioasong , Yuan Chunwai , Chen Shujian , Zhang Peiyun , Zhang Tianyi , Yao Jian , Chen Fen , Chen Gang 
Published: January 2004

AbstractIn this study, the biocompatibility of the electrically conductive polymer polypyrrole (PPy) with nerve tissue was evaluated in vitro and in vivo. The extraction solution of PPy powder, which was synthesized chemically, was tested for acute toxicity, subacute toxicity, pyretogen, quantitative measure of cell viability, hemolysis, allergen, and micronuclei. The PPy membrane was synthesized electrochemically on the indium tin oxide conductive borosilicate glass. The dorsal root ganglia from 1–3‐day‐old Sprague‐Dawley rats were cultured above PPy membrane and observed by light or scanning electron microscopy. The PPy‐silicone tube (PPy membrane on the inner surface of the silicone tube) also synthesized electrochemically was used to bridge across 10‐mm sciatic nerve gap in rats. Twenty‐four weeks after the operation to rats, the regenerated tissues were observed by electrophysiological and histological techniques. PPy extraction solution showed no evidence of acute and subacute toxicity, pyretogen, hemolysis, allergen, and mutagenesis, and the Schwann cells from the PPy extraction solution group showed better survival rate and proliferation rate as compared with the saline solution control group. The migration of the Schwann cells and the neurite extension from dorsal root ganglia on the surface of PPy membrane‐coated glass was better than those of bare glass. There was only lightly inflammation during 6 months of the postoperation, when the PPy‐silicone tube bridged across the gap of the transected sciatic nerve. The regeneration of nerve tissue in the PPy‐silicone tube was slightly better than that in the plain silicone tube by means of electrophysiological and histological examination. The results of this study indicate that PPy has a good biocompatibility with rat peripheral nerve tissue and that PPy might be a candidate material for bridging the peripheral nerve gap. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 411–422, 2004
Ongoing foreign body reaction to subcutaneous implanted (heparin) modified Dacron in rats
Authors: van Bilsen Paul H. J. , Popa Eliane R. , Brouwer Linda A. , Vincent Judith , Taylor Catherine E. , de Leij Lou F. M. H. , Hendriks Marc , van Luyn Marja J. A. 
Published: January 2004

AbstractDacron‐containing heart valve repair devices trigger chronic inflammation characterized by the presence of activated macrophages, foreign body giant cells, and capsule formation. Upon blood contact, proinflammatory proteins adsorb to the material and provide a substrate for monocyte binding and differentiation. Various heparin‐coated polymers have been shown to reduce adsorption of proinflammatory proteins in vitro and in vivo. In this study, the effect of knitted, heparin‐coated Dacron on the foreign body reaction was tested subcutaneously in rats. We hypothesized that the anti‐inflammatory effect of heparin would reduce monocyte recruitment and differentiation and therefore limit the inflammatory reaction. An ongoing foreign body reaction, characterized by the presence of foreign body giant cells and high vascularization, was observed in uncoated as well as (heparin‐)coated Dacron at up to 180 days of implantation. Also, a thin capsule was formed around each material up to this time. In conclusion, although heparin coatings might have an effect on the acute inflammatory response, we were not able to show a difference between heparin‐coated and uncoated Dacron after 180 days' implantation in rats. Further research needs to be conducted to assess the difference in proinflammatory protein adsorption between the tested materials and the effect this has on the long‐term foreign body reaction. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 423–427, 2004
Effect of biomaterial properties on bone healing in a rabbit tooth extraction socket model
Authors: Fisher John P. , Lalani Zahid , Bossano Carla M. , Brey Eric M. , Demian Nagi , Johnston Carol M. , Dean David , Jansen John A. , Wong Mark E. K. , Mikos Antonios G. 
Published: January 2004

AbstractIn this work we sought to understand the effect of biomaterial properties upon healing bone tissue. We hypothesized that a hydrophilic polymer gel implanted into a bone tissue defect would impede the healing process owing to the biomaterial's prevention of protein adsorption and thus cell adhesion. To test this hypothesis, healing bone was investigated within a rabbit incisor extraction socket, a subcritical size bone defect that resists significant soft tissue invasion by virtue of its conformity. After removal of the incisor teeth, one tooth socket was left as an empty control, one was filled with crosslinked polymer networks formed from the hydrophobic polymer poly(propylene fumarate) (PPF), and one was filled with a hydrogel formed from the hydrophilic oligomer oligo(poly(ethylene glycol) fumarate) (OPF). At five different times (4 days as well as 1, 2, 4, and 8 weeks), jaw bone specimens containing the tooth sockets were removed. We analyzed bone healing by histomorphometrical analysis of hematoxylin and eosin stained sections as well as immunohistochemically stained sections. The proposed hypothesis, that a hydrophilic material would hinder bone healing, was supported by the histomorphometrical results. In addition, the immunohistochemical results reflect molecular signaling indicative of the early invasion of platelets, the vascularization of wound‐healing tissue, the differentiation of migrating progenitor cells, and the formation and remodeling of bone tissue. Finally, the results emphasize the need to consider biomaterial properties and their differing effects upon endogenous growth factors, and thus bone healing, during the development of tissue engineering devices. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 428–438, 2004
RGD‐containing peptide GCRGYGRGDSPG reduces enhancement of osteoblast differentiation by poly(L‐lysine)‐graft‐poly(ethylene glycol)‐coated titanium surfaces
Authors: Tosatti S. , Schwartz Z. , Campbell C. , Cochran D. L. , VandeVondele S. , Hubbell J. A. , Denzer A. , Simpson J. , Wieland M. , Lohmann C. H. , Textor M. , Boyan B. D. 
Published: January 2004

AbstractOsteoblasts exhibit a more differentiated morphology on surfaces with rough microtopographies. Surface effects are often mediated through integrins that bind the RGD motif in cell attachment proteins. Here, we tested the hypothesis that modulating access to RGD binding sites can modify the response of osteoblasts to surface microtopography. MG63 immature osteoblast‐like cells were cultured on smooth (Ti sputter‐coated Si wafers) and rough (grit blasted/acid etched) Ti surfaces that were modified with adsorbed monomolecular layers of a comb‐like graft copolymer, poly‐(L‐lysine)‐g‐poly(ethylene glycol) (PLL‐g‐PEG), to limit nonspecific protein adsorption. PLL‐g‐PEG coatings were functionalized with varying amounts of an integrin‐receptor‐binding RGD peptide GCRGYGRGDSPG (PLL‐g‐PEG/PEG‐RGD) or a nonbinding RDGcontrol sequence GCRGYGRDGSPG (PLL‐g‐PEG/PEG‐RDG). Response to PLL‐g‐PEG alone was compared with response to surfaces on which 2–18% of the polymer sidechains were functionalized with the RGD peptide or the RDGpeptide. To examine RGD dose–response, peptide surface concentration was varied between 0 and 6.4 pmol/cm2. In addition, cells were cultured on uncoated Ti or Ti coated with PLL‐g‐PEG or PLL‐g‐PEG/PEG‐RGD at an RGD surface concentration of 0.7 pmol/cm2, and free RGDS was added to the media to block integrin binding. Analyses were performed 24 h after cultures had achieved confluence on the tissue culture plastic surface. Cell number was reduced on smooth Ti compared to plastic or glass and further decreased on surfaces coated with PLL‐g‐PEG or PLL‐g‐PEG/PEG‐RDG, but was restored to control levels when PLL‐g‐PEG/PEG‐RGD was present. Alkaline phosphatase specific activity and osteocalcin levels were increased on PLL‐g‐PEG alone or PLL‐g‐PEG/PEG‐RDG, but PLL‐g‐PEG/PEG‐RGD reduced the parameters to control levels. On rough Ti surfaces, cell number was reduced to a greater extent than on smooth Ti. PLL‐g‐PEG coatings reduced alkaline phosphatase and increased osteocalcin in a manner that was synergistic with surface roughness. The RDGpeptide did not alter the PLL‐g‐PEG effect but the RGD peptide restored these markers to their control levels. PLL‐g‐PEG coatings also increased TGF‐β1 and PGE2in conditioned media of cells cultured on smooth or rough Ti; there was a 20× increase on rough Ti coated with PLL‐g‐PEG. PLL‐g‐PEG effects were inhibited dose dependently by addition of the RGD peptide to the surface. Free RGDS did not decrease the effect elicited by PLL‐g‐PEG surfaces. These unexpected results suggest that PLL‐g‐PEG may have osteogenic properties, perhaps correlated with effects that alter cell attachment and spreading, and promote a more differentiated morphology. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 458–472, 2004
Vitronectin adsorption on surfaces visualized by tapping mode atomic force microscopy
Authors: Zhang Hailong , Bremmell Kristen , Kumar Sunil , Smart Roger St. C. 
Published: January 2004

AbstractVitronectin (Vn) is an abundant glycoprotein present in plasma and the extracellular matrix of most tissue and is an important medium required for bone cells to attach and spread on biomaterial surfaces. Hence, Vn adsorption is an initial and key step in implantation. In this study, adsorption of Vn molecules on mica and oxidized titanium substrates in Milli‐Q water (pH 5.6) and in simulated body fluid (SBF, pH 7.4) has been investigated using tapping mode atomic force microscopy. Conformation of the adsorbed proteins was determined from the images. The effect of adsorption time was investigated on mica surfaces. The protein first attaches to the surface, then immediately spreads out with different lateral dimensions of adsorbed protein and becomes aggregated. After 15 min of adsorption, globular Vn molecules form clusters of aggregates in extended chains on the mica surface. Globular Vn molecules appear flatter (i.e., oblate ellipsoids) and coalesce on the ridges of the uneven oxidized titanium surface. From cross‐sectional analyses of the Vn images, it was found that the contact areas of Vn molecules associated with Ti surfaces are larger than those with mica surfaces. This suggests that the different surface properties of substrates contribute to this different conformation of adsorbed Vn molecules. The larger contact areas of Vn associated with Ti substrates indicates higher affinity for the biomaterial oxidized titanium surface than for mica. In SBF, Vn interacted weakly with the mica surfaces and Vn molecules were easily desorbed during the imaging process. On oxidized titanium substrates, after 3 h of incubation time in Vn–SBF solution, images can be obtained showing adsorbed Vn aggregates on the oxidized titanium surface. In this case, the protein colloids are strongly adherent, with increased lateral dimensions compared with the adsorption on mica. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 479–488, 2004
Systematic variation in osteoblast adhesion and phenotype with substratum surface characteristics
Authors: Lim Jung Yul , Liu Xiaomei , Vogler Erwin A. , Donahue Henry J. 
Published: January 2004

AbstractTime‐varying interactions of human fetal osteoblastic cells (hFOB 1.19) with materials of diverse chemical composition and surface energy, including biodegradable lactide/glycolide‐based polymers, were assessed using a combination of assays sensitive to different phases of cell‐substratum compatibility. Short‐term (minutes to hours) cell‐attachment‐rate assays were used to measure the earliest stages of cell‐surface interactions leading to adhesion. Proliferation‐rate assays quantifying viability of attached cells were applied as a measure of medium‐term (hours to days) cytocompatibility. Both attachment‐ and proliferation‐rate assays were found to strongly correlate with material surface energy, with the exception of a reproducible and significant adhesion preference for fully water‐wettable quartz over glass. No such adhesion/proliferation preference was observed for hydrophobized counterparts, and attachment to water‐wettable glass was significantly less than that to control tissue culture polystyrene. These results suggest that the amorphous SiOx surface was inhibitory to hFOB 1.19 growth whereas putatively crystalline quartz stimulated bioadhesion. Alkaline phosphatase activity was evaluated as a marker for long‐term (days) differentiation of hFOB 1.19 cells and did not strongly correlate with surface energy or, in the case of biodegradable polymers, chemical composition. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 504–512, 2004
Effect of cyclic mechanical stretch and titanium particles on prostaglandin E2 production by human macrophages in vitro
Authors: Fujishiro Takaaki , Nishikawa Tetsuo , Shibanuma Nao , Akisue Toshihiro , Takikawa Satoshi , Yamamoto Tetsuji , Yoshiya Shinichi , Kurosaka Masahiro 
Published: January 2004

AbstractEarly implant instability has been proposed as a critical factor in the onset and progression of aseptic loosening and periprosthetic osteolysis in total joint arthroplasties. Previous in vitro studies have reported that macrophages stimulated with cyclic mechanical strain release inflammatory mediators. Little is known, however, about the response of these cells to mechanical strain with particles, which is often a component of the physical environment of the cell. We therefore studied the production of prostaglandin E2 (PGE2), an important mediator in aseptic loosening and periprosthetic osteolysis in total joint arthroplasties, for human macrophages treated with mechanical stretch alone, titanium particles alone, and mechanical stretch and particles combined. A combination of mechanical stretch and titanium particles resulted in a statistically synergistic elevation of levels of PGE2 compared with the levels found with either stretch or particles alone. Exposure of human macrophages to mechanical stretch with particles upregulated the expression of cyclooxygenase (COX)‐2 mRNA but not COX‐1 mRNA, this expression resulting in a 97‐fold increase in PGE2 production compared to the nonstimulated cells. The current study is the first to investigate the effects of mechanical stretch with particles on cultured macrophages and include an investigation of the time course of PGE2 production and COX‐2 mRNA expression. Our results suggest that, while mechanical strain may be one of the primary factors responsible for macrophage activation and periprosthetic osteolysis, mechanical strain with particles load may contribute significantly to the osteolytic potential of macrophages in vitro. The synergistic effect observed between mechanical stretch and particles could accelerate implant loosening and implies that reduction in either cyclic mechanical strain or wear debris load would lead to a reduction of osteolysis. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 531–536, 2004
Transforming growth factor‐β1 accelerates bone bonding to a blended calcium phosphate ceramic coating: A dose‐response study
Authors: Szivek John A. , Nelson Ehren R. , Hajdu Steven D. , Yablonski Kelly , DeYoung Don W. 
Published: January 2004

AbstractIn vivo strain measurements can facilitate the study of the bone remodeling response to loading and load changes. Calcium phosphate ceramic (CPC) coatings have been used to attach strain gauges to bone for extended periods of time, but require up to 12 weeks for adequate CPC‐to‐bone bonding. Transforming growth factor beta 1 (TGF‐β1), an osteoinductive growth factor, was used as a surface enhancement to accelerate bone growth and bonding to CPC particles. The aim of this study was to find an optimal dosage of TGF‐β1 to accelerate the attachment process. CPC‐coated strain gauges were enhanced with doses of 0.5, 1.0, or 2.0 μg of TGF‐β1 per gauge. Gauges were placed on the femora of dogs, which were exercised daily and fed ad libitum. After 3, 6, and 12 weeks, gauge attachment was quantitatively assessed using mechanical testing and histomorphometry. Gauge attachment was also qualitatively assessed using back scatter electron microscopy. Agreement of the mechanical test results with both the back scatter electron microscopy images and histomorphometry results showed that the 1.0 μg per gauge dose of TGF‐β1 is an optimal dose to accelerate bone formation and attachment to CPC‐coated strain gauges. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 537–543, 2004
In search of evolutionary developmental mechanisms: The 30‐year gap between 1944 and 1974
Authors: Hall Brian K. 
Published: January 2004

AbstractThe approach I have elected in this retrospective of how I became a student of evo‐devo is both biographical and historical, a case study along the lines of Waddington's The Evolution of an Evolutionist ('75), although in my case it is the Evolution of an Evo‐devoist. What were the major events that brought me to developmental biology and from there to evo‐devo? They were, of course, specific to my generation, to the state of knowledge at the time, and to my own particular circumstances. Although exposed to evolution and embryology as an undergraduate in the 1960s, my PhD and post‐PhD research programme lay within developmental biology until the early 1970s. An important formative influence on my studies as an undergraduate was the work of Conrad Hal Waddington (1905–1975), whose writings made me aware of genetic assimilation and gave me an epigenetic approach to my developmental studies. The switch to evo‐devo (and my discovery of the existence of the neural crest), I owe to an ASZ (now SICB) symposium held in 1973. J. Exp. Zool. (Mol. Dev. Evol.) 302B:5–18, 2004. © 2004 Wiley‐Liss, Inc.
Kowalevsky, comparative evolutionary embryology, and the intellectual lineage of evo‐devo
Authors: Raff Rudolf A. , Love Alan C. 
Published: January 2004

AbstractAlexander Kowalevsky was one of the most significant 19th century biologists working at the intersection of evolution and embryology. The reinstatement of the Alexander Kowalevsky Medal by the St. Petersburg Society of Naturalists for outstanding contributions to understanding evolutionary relationships in the animal kingdom, evolutionary developmental biology, and comparative zoology is timely now that Evo‐devo has emerged as a major research discipline in contemporary biology. Consideration of the intellectual lineage of comparative evolutionary embryology explicitly forces a reconsideration of some current conceptions of the modern emergence of Evo‐devo, which has tended to exist in the shadow of experimental embryology throughout the 20th century, especially with respect to the recent success of developmental biology and developmental genetics. In particular we advocate a sharper distinction between the heritage of problems and the heritage of tools for contemporary Evo‐devo. We provide brief overviews of the work of N. J. Berrill and D. T. Anderson to illustrate comparative evolutionary embryology in the 20th century, which provides an appropriate contextualization for a conceptual review of our research on the sea urchin genus Heliocidaris over the past two decades. We conclude that keeping research questions rather than experimental capabilities at the forefront of Evo‐devo may be an antidote to any repeat of the stagnation experienced by the first group of evolutionary developmental biologists over one hundred years ago and acknowledges Kowalevsky's legacy in evolutionary embryology. J. Exp. Zool. (Mol Dev. Evol.) 302B:19–34, 2004. © 2004 Wiley‐Liss, Inc.
Effects of land use on soil erosion and nitrogen loss in the hilly area of the Loess Plateau, China
Authors: Fu B. J. , Meng Q. H. , Qiu Y. , Zhao W. W. , Zhang Q. J. , Davidson D. A. 
Published: January 2004

AbstractThis study examines the effects of land use and slope angle on runoff, soil loss and nitrogen loss from hillslopes of the Loess Plateau in China. Farmland, wasteland and four forest treatments (sea buckthorn+poplar, immature sea buckthorn, mature sea buckthorn, and immature Chinese pine) were the types of land use that were compared. The results showed that July was the critical period for runoff, soil loss and nitrogen loss from farmland. Farmland was the most susceptible land use. Sea buckthorn+poplar, immature sea buckthorn, and mature sea buckthorn limited the runoff, soil loss and nitrogen loss. Farmland on slopes over 15 degrees should be abandoned because of the high erosion rate and nitrogen loss. Copyright © 2003 John Wiley & Sons, Ltd.