bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relation‐based intervention with at‐risk mothers: Outcome in the second year of life
Authors: Heinicke Christoph M. , Fineman Neira R. , Ponce Victoria A. , Guthrie Donald 
Published: August 2002

AbstractIt has been shown that the UCLA home visiting/mother–infant group intervention made a significant positive impact during the child's first 2 years of life on two indices of the mother's support and on three areas of mother–child and child development: (1) The mother's responsiveness to the needs of her child and the related development of his or her security of attachment; (2) the mother's encouragement of her child's autonomy and the related development of his or her autonomy; and (3) the mother's encouragement of her child's task involvement and the related development of his or her task orientation. By child age 2 years, the mothers experiencing the intervention, in comparison with those that did not, also used verbally persuasive as opposed to coercive intrusive methods of control and their children responded more positively to these controls. Mothers who did not experience the help of the intervention had significantly more difficulty controlling their child if it was a boy as opposed to a girl. They used the least appropriate methods of control, and the boys responded more negatively to these controls.The nature of the development of the mother's use of appropriate controls and the child's response to that control was elucidated by determining on the total sample where 12‐month antecedents influenced the indices of control either independently of or in interaction with the intervention status. The child's endurance in the test situation was an independent predictor of mother‐appropriate control and the child's positive response to that control, while the absence of maternal intrusiveness further enhanced the impact of the intervention on that control. ©2001 Michigan Association for Infant Mental Health.
Sediment transport applications in irrigation canals
Authors: Depeweg Herman , Méndez V Néstor 
Published: August 2002

AbstractSediment transport in irrigation canals is an important issue in the design and operation of irrigation systems. Frequently observed problems in irrigation systems are, for example, clogging of turnouts and reduction of the conveyance capacity of canals by siltation, and instability of side slopes and of structures due to erosion. Each year large investments are required to maintain or to rehabilitate these systems and to keep them in an acceptable condition for irrigation purposes.Irrigation canals are generally designed based on the assumption of uniform and steady flow of water and sediments. However, the flow is predominantly non‐uniform, due to time‐dependent discharges and constant water levels at regulation and division points. A strong relationship exists between the sediment transport and flow conditions.The aim of this article is to present some new developments in the behaviour of sediment and associated sediment transport in irrigation canals under changing flow conditions, as well as the deposition and/or entrainment rate in time and place for various flow conditions and sediment inputs. This article will discuss an approach to compute sediment transport in irrigation canals under non‐uniform flow conditions. The sediment transport has been analysed for the flow conditions that prevail in irrigation canals. The Ackers‐White and Brownlie equations are recommended to compute the sediment transport under equilibrium conditions for prismatic canal cross‐sections. For non‐equilibrium conditions, a numerical solution of Galappatti's depth‐integrated model is applied. Copyright © 2002 John Wiley & Sons, Ltd.
Water at any price? Issues and options in charging for irrigation water1
Authors: Perry Chris 
Published: August 2002

AbstractShortage of water and inadequate funding for maintenance of irrigation works have focused attention on the potential for water charges to generate financial resources, and reduce demand for water through volume‐based charges. Examples from other utilities, and from the domestic/industrial sectors of water supply, suggest the approach could be effective.However, in many developing countries, the facilities required for measured and controlled delivery, which are both essential for volume‐related charges, are not in place and their introduction would require a massive investment in physical, legal and administrative infrastructure.To be effective in curtailing demand, the price of water must be significant, but the price structures and levels that are within the politically feasible and acceptable range are usually too low to have a real impact on demand, much less to actually bring supply and demand into balance. Similarly, the present cost of water is too low to induce significant technical innovation or investments that could reduce consumption.Moreover, while water supplied is a proper measure of service in domestic and industrial uses, in irrigation, and especially as the water resource itself becomes constrained, water consumption is the appropriate measure for water accounting, and this is exceptionally difficult to define.An alternative approach to coping with shortage would focus on assigning volumes to specific uses – and effectively rationing water where demand exceeds supply – has a number of potential benefits including simplicity, transparency and the potential to tailor allocations specifically to hydrological situations. Copyright © 2001 John Wiley & Sons Ltd.
Enhancing the predictive validity of Frog Embryo Teratogenesis Assay—Xenopus (FETAX)
Authors: Fort Douglas J. , Paul Robbin R. 
Published: August 2002

AbstractFrog Embryo Teratogenesis Assay—Xenopus (FETAX) is a 4‐day, alternative developmental toxicity assay designed to pre‐screen chemicals and environmental mixtures. An approach used in the scoring of FETAX results, which focuses on the determination of characteristic abnormalities induced by a given test material, was used to evaluate results from previous validation efforts. Characteristic abnormalities are induced specifically by exposure to a given test material and are determined by the relationship between concentration and the response induced and the change in severity of response. Use of this approach eliminates non‐specific effects that alter numerical endpoints, reduces intralaboratory variability, reduces the number of equivocal test results (gray area), helps to determine specific syndromes associated with teratogen exposure and, in some instances, increases the predictability of FETAX. In an effort to evaluate this approach, a 12‐compound validation study that produced a relatively high degree of equivocal FETAX results was re‐evaluated using the characteristic malformation criteria. Data were evaluated for repeatability, predictability and variability. Results from this study indicated that this scoring approach increased repeatability, test endpoint precision and predictability. Copyright © 2002 John Wiley & Sons, Ltd.
Biocompatibility studies on biodegradable polyester‐based composites of human osteoblasts: A preliminary screening
Authors: Calandrelli L. , Immirzi B. , Malinconico M. , Orsello G. , Volpe M. G. , Ragione F. Della , Zappia V. , Oliva A. 
Published: August 2002

AbstractA series of biodegradable composites with natural hydroxyapatite, designed for possible use in orthopedics applications, were preliminarily screened for biocompatibility by employing primary cultures of human osteoblasts in a direct contact method. The cells were seeded at low density onto the materials under investigation and allowed to grow for 2 weeks. They then were analyzed for morphology, proliferation, viability, alkaline phosphatase activity (AP), osteocalcin (OC) production, and extracellular matrix mineralization. The results showed that all materials have good biocompatibility. Cell viability tests demonstrated that in all cases the values were comparable to the control, and the addition of hydroxyapatite always resulted in an enhancement of performance with respect to the plain polymer. AP and OC analysis confirmed that all composites allowed the expression of phenotypic markers. Scanning electron microscopy provided direct evidence of intense cell adhesion and proliferation on the tested materials. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 611–617, 2002
Characterization of melt‐derived 45S5 and sol‐gel–derived 58S bioactive glasses
Authors: Sepulveda Pilar , Jones Julian R. , Hench Larry L. 
Published: August 2002

AbstractThe ability of bioactive glasses to form a bond to living bone and also to stimulate bone‐cell proliferation depends on the chemical composition and on the surface texture of the glasses. In this work, the differences in physical properties between the melt‐derived 45S5 and sol‐gel–derived 58S Bioglass® powders of various particle‐size ranges were studied. The powders were characterized for particle‐size distribution by laser spectrometry, for specific surface area and porosity by nitrogen sorption analysis, and for morphological features by scanning electron microscopy. Melt‐derived 45S5 powders exhibited a low‐porosity texture with surface area in the range 0.15–2.7 m2/g. In contrast, the sol‐gel–derived powders exhibited a highly mesoporous texture, with surface area in the range of 126.5–164.7 m2/g and a large fraction of 6–9 nm pore sizes. These differences in texture, as well as variations in chemical composition, account for significant changes in the resorption and in vivo responses. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 734–740, 2001
In vivo evaluation of a new sealant material on a rat lung air leak model
Authors: Kobayashi Hisatoshi , Sekine Takashi , Nakamura Tatsuo , Shimizu Yasuhiko 
Published: August 2002

AbstractThe ability of an albumin‐based hydrogel sealant (ABHS) to prevent air leakage through the suture line after pulmonary surgery was evaluated by comparison with that of a fibrin glue (FG). As an air‐leak model, a rat lung was used in which a standard incision was made and the burst pressure for ABHS and FG was measured. The average burst pressures at time 0 for the FG and ABHS groups were 30.8±15.2 and 77.5 ±19.1 mmHg, respectively. At Day 3, the value of ABHS (76.3 ± 15.8 mmHg) was still significantly higher (P<0.05) than that of FG (60.0 ± 21.9 mmHg). At Day 7, no statistical difference was observed between the FG group(71.2 ± 18.6 mmHg) and the ABHS group(88.8 ± 11.7 mmHg). Histological examination of the incision at Day 14 revealed that neither sealant was not visible at the incision site, and there was no evidence of adverse tissue reaction. It was concluded that ABHS had good sealing properties and is an alternative to FG for air leakage treatment in pulmonary surgery. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 658–665, 2001
Novel hydroxyapatite ceramics with an interconnective porous structure exhibit superior osteoconduction in vivo
Authors: Tamai Noriyuki , Myoui Akira , Tomita Tetsuya , Nakase Takanobu , Tanaka Junzo , Ochi Takahiro , Yoshikawa Hideki 
Published: August 2002

AbstractCalcium hydroxyapatite ceramics (CHA) are nontoxic materials, provoke little reaction from tissues, and by virtue of these properties represent a good starting point for creating bone substitutes. Although several porous CHAs have been used clinically, there have been few reports that CHA is fully replaced by newly formed bone, which may be due to its structure and the limited connectivity between pores. We recently developed a fully interconnected porous CHA (IP‐CHA) by adopting a “foam‐gel” technique. Structural analysis by scanning electron microscopy revealed that IP‐CHA had spherical pores of uniform size that were interconnected by window‐like holes. The surface of the wall structure was smooth, and hydroxyapatite particles were bound tightly to one another. Most of the interpore connections of IP‐CHA ranged from 10 to 80 μm in diameter (average, 40 μm). When the cylindrical IP‐CHA (diameter, 6 mm; height, 15 mm) was implanted into a rabbit femoral condyle, bone, and bone marrow with abundant vessels formed deep in the pores through the interpore connections. Within a period of 6 weeks, new bone had formed and penetrated to a distance of 3 mm from the surface of the IP‐CHA implant. Furthermore, a compression test at 9 weeks revealed that the implanted IP‐CHA steadily increased in strength to more than double the value of the initial test. These results indicate that the IP‐CHA may have clinical utility as a superior bone substitute. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 110–117, 2002
Albumin adsorption onto pyrolytic carbon: A molecular mechanics approach
Authors: Mantero Sara , Piuri Daniela , Montevecchi Franco M. , Vesentini Simone , Ganazzoli Fabio , Raffaini Giuseppina 
Published: August 2002

AbstractA number of implants of cardiac valve prosthesis, vascular prosthesis, and coronary stents present a pyrolytic carbon interface to blood. Plasma protein adsorption is essential for the hemocompatibility of the implanted devices. This work quantitatively evaluates the molecular interaction force between a biomaterial surface (pyrolytic carbon) and plasma protein (albumin) binding sites through a simplified molecular model of the interface consisting of (i) multioriented graphite microcrystallites; (ii) selected fragments of albumin; and (iii) a water environment. A number of simplifying assumptions were made in the calculation: the albumin molecule was divided into hydrophobic and hydrophilic subunits (helices); an idealized clean, nonoxidized polycrystalline graphite surface was assumed to approximate the surface of pyrolytic carbon. The interaction forces between albumin helices and pyrolytic carbon surfaces are evaluated from potential energy data. These forces are decomposed into a normal and a tangential component. The first one is calculated using a docking procedure (F⊥tot MAX = 4.16 × 10−20 N). The second one (F‖), calculated by mean of geometric models estimating the energy variation associated with the protein sliding on the material surface, varies within the range ±9.62 × 10−21 N. The molecular simulations were performed using the commercial software package Hyperchem 5.0 (Hyperchem, Hypercube, Canada). © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 329–339, 2002
Osseointegration of hydroxyapatite‐coated and noncoated Ti6Al4V implants in the presence of local infection: A comparative histomorphometrical study in rabbits
Authors: Oosterbos C. J. M. , Vogely H. Ch. , Nijhof M. W. , Fleer A. , Verbout A. J. , Tonino A. J. , Dhert W. J. A. 
Published: August 2002

AbstractA study was designed to investigate the osseointegration of titanium implants, either noncoated or coated with hydroxyapatite (HA), into rabbit tibiae in the presence of local infection compared with osseointegration in the absence of local infection. HA‐coated or noncoated Ti cylinders were implanted into both tibiae of 32 rabbits (New Zealand Whites). Before implantation the left tibia was contaminated with different quantities of Staphylococcus aureus (102–105 CFU). Four weeks after surgery the tibiae were explanted and prepared for microbiological and histomorphometrical examination. Histomorphometrical data, as a representation of implant fixation, were obtained by measuring the percentage of bone around the implants (within a radius of 1 mm from the outer diameter of the implants) and the percentage of the circumference of the implant that was in direct contact with bone. Histomorphometry revealed, in particular for the HA implants, a relationship between the inoculum concentration and/or the presence or absence of infection with the bone contact at the distal implant side. This confirms a relationship between peri‐implant infection and bone contact or remodeling. HA‐coated implants developed, in the presence of bacteria, more easily a more severe infection than noncoated Ti implants, and we show in the present study that local infection will influence histomorphometrical parameters (bone‐implant contact) that determine implant fixation. Precautions to prevent contamination (asepsis) and/or infection (perioperative antibiotics) are even more important for the highly biocompatible HA‐coated implant. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 339–347, 2002; DOI 10.1002/jbm.1288
Differences in the nuclear chromatin among various stages of the life cycle of Trypanosoma cruzi
Authors: Spadiliero Barbara , Sánchez Fredi , Slezynger Thelma C. , Henríquez Diana A. 
Published: August 2002

AbstractTrypanosoma cruzi is the etiological agent of Chagas. Although the nuclear chromatin of this parasite is organized in the form of nucleosome filaments, its chromatin is physically and enzymatically fragile, and no condensation into chromosomes occurs during mitosis. All previous investigations have been carried out with epimastigote form in its proliferate stage. It is not known whether these differences in chromatin structure are also found in the non‐proliferate stationary epimastigote forms and in tissue derived trypomastigotes. Our results confirm that chromatin of logarithmic epimastigotes presents limited compaction when increasing salt concentrations from 1 to 100 mM NaCl, and no 30‐nm fibers were formed. Contrary to these results, non‐proliferative forms of the parasites showed a pattern of compactation similar to that observed in rat liver chromatin, where solenoids of 30‐nm fibers are formed at 100‐mM NaCl. In accordance with these results, digestion of the nuclear chromatin with DNase I revealed that the chromatin of logarithmic phase epimastigotes was more accesible to the enzyme. We conclude from these results that structural differences in the chromatin exist not only between T. cruzi and higher eukaryotes but also among various forms of the parasite. The functional significance of these differences are currently under investigation. J. Cell. Biochem. 84: 832–839, 2002. © 2002 Wiley‐Liss, Inc.
Mutation in collagen gene induces cardiomyopathy in transgenic mice*
Authors: Miller Amanda D. , Tyagi Suresh C. 
Published: August 2002

AbstractIn many remodeling tissues, such as the heart, collagen degradation to provide new integrin‐binding sites is required for survival. However, complete loss of integrin signaling due to disconnection from extracellular matrix (ECM) leads to apoptosis and dilatation. To test the hypothesis that a mutation in type I collagen gene induces cardiomyopathy, we employed a metalloproteinase‐resistant collagen mutant homozygous transgenic male (B6,129‐Colla‐1) and compared with age‐sex matched wildtype C57BL/J6 control mice. At the age of 38–42 weeks, aortic and left ventricle (LV) pressure were measured. The LV wall thickness and diameter were measured by a digital micrometer. The levels of matrix metalloproteinase‐2 (MMP‐2) activity and cardiospecific tissue inhibitor of metalloproteinase‐4 (TIMP‐4) were measured by zymography and Western blot analyses, respectively. The levels of collagenolysis were measured by Western blot using anti‐collagen antibody. In transgenic and wildtype mice, end‐diastolic pressure (EDP) was 8.3 ± 1.7 and 6.5 ± 1.1 mmHg; LV diameter was 3.43 ± 0.07 and 2.94 ± 0.05 mm; wall thickness was 1.18 ± 0.03 and 1.28 ± 0.04 mm; end‐diastolic wall stress was 600 ± 158 and 347 ± 49 dynes/cm2, respectively. The increase in LV wall stress was associated with increased MMP‐2 activity, increased collagenolysis, and decreased levels of TIMP‐4. This leads to reduced elastic compliance in collagen mutant transgenic mice. The occurrence of cardiomyopathy in adult Colla‐1 mice may be a significant confounding factor as it may be indicative of increased basal levels of ECM disruption. This phenotype is what would be expected if collagen degradation normally supplies integrin ligands during cardiac muscle remodeling. J. Cell. Biochem. 85: 259–267, 2002. © 2002 Wiley‐Liss, Inc.
Reversible hypercondensation and decondensation of mitotic chromosomes studied using combined chemical–micromechanical techniques
Authors: Poirier Michael G. , Monhait Tamar , Marko John F. 
Published: August 2002

AbstractWe show that the chromatin in mitotic chromosomes can be drastically overcompacted or unfolded by temporary shifts in ion concentrations. By locally ‘microspraying’ reactants from micron‐size pipettes, while simultaneously monitoring the size of and tension in single chromosomes, we are able to quantitatively study the dynamics of these reactions. The tension in a chromosome is monitored through observation and calibration of bending of the glass pipettes used to manipulate the chromosomes. For concentrations > 500 mM of NaCl and > 200 mM of MgCl2, we find that the initially applied tensions of ∼ 500 pN relax to zero and that mitotic chromatin temporarily disperses in agreement with previous work (Maniotis et al. [1997] J. Cell. Biochem. 65:114–130). This unfolding occurs in about 1 s, and is reversible once the charge density is returned to physiological levels, if the exposure is not longer than ∼ 1 min. Low concentrations of NaCl (< 30 mM) also induces a decrease in tension and increase in size. We observe this swelling to be isotropic in experiments on chromosomes under zero tension, a behavior inconsistent with the existence of a well‐defined central chromosome ‘scaffold’. By contrast 10 mM of divalent cations (MgCl2 and CaCl2) induces an extremely rapid and reversible increase in tension and a reduction in the size of mitotic chromosomes. Hexaminecobalt trichloride (trivalent cation) has the same effect as MgCl2 and CaCl2, except the magnitude of force increase and size change are much larger. Hexaminecobalt trichloride reduces mitotic chromosomes to 65% of their original volume, indicating that at least 1/3 of their apparent volume is aqueous solution. These results indicate that chromatin inside mitotic chromatids has a large amount of conformational freedom allowing dynamic unfolding and refolding and that charge interactions play a central role in maintaining mitotic chromosome structure. J. Cell. Biochem. 85: 422–434, 2002. © 2002 Wiley‐Liss, Inc.
Stimulatory effect of endothelin‐1 on Na‐dependent phosphate transport and its signaling mechanism in osteoblast‐like cells
Authors: Masukawa Hiroko , Miura Yoshitaka , Sato Ikuko , Oiso Yutaka , Suzuki Atsushi 
Published: August 2002

AbstractEndothelin‐1 (ET‐1) has been reported to modulate bone metabolism both in vivo and in vitro. In the present study, we investigated the effect of ET‐1 on inorganic phosphate (Pi) transport in osteoblast‐like cells, which is now considered to be important for the initiation of bone matrix calcification. ET‐1 time‐ and dose‐dependently stimulated Na‐dependent Pi transport in mouse calvaria‐derived osteoblast‐like MC3T3‐E1 cells, and this effect was dependent on transcriptional and translational process. Kinetic analysis indicated that the change in Pi transport activity induced by ET‐1 was due to alteration in the number of the Pi transporter. BQ123, a selective antagonist for ETA receptor, suppressed the ET‐1‐induced Pi transport, but BQ788, a selective antagonist for ETB receptor, had no effect. The inhibition of phosphoinositide hydrolysis by phospholipase C (PLC) partially attenuated the Pi transport by ET‐1. Propranolol, which inhibits phosphatidic acid phosphohydrolase, also suppressed ET‐1‐induced Pi transport. On the contrary, indomethacin did not affect the stimulatory effect of Pi transport by ET‐1. Calphostin C, a protein kinase C (PKC) inhibitor, significantly blunted the stimulatory effect of ET‐1 on Pi transport. Combined effect of PMA and ET‐1 on Pi transport was not additive. Pi transport induced by ET‐1 was also suppressed in PKC down‐regulated cells. In conclusion, the results of the present study indicate that in MC3T3‐E1 osteoblast‐like cells, ET‐1 acting through ET receptor links to a stimulation of Pi transport via activation of PKC through both phosphoinositide and phosphatidylcholine hydrolyses. © 2001 Wiley‐Liss, Inc.