bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐income adolescent mothers' knowledge about domains of child development
Authors: Tamis‐Lemonda Catherine S. , Shannon Jacqueline , Spellmann Mark 
Published: August 2002

AbstractSixty low‐income adolescent mothers of children ranging in age from birth to 28 months were asked to estimate the ages at which children are first able to engage in specific activities in cognitive, language, motor, play, and social development. In general, mothers were quite knowledgeable about the ordering of developmental abilities relative to one another, but were less knowledgeable about the developmental timing of abilities. With respect to timing, mothers tended to underestimate the onset of all developmental abilities. That is, mothers predicted that children's developmental abilities would appear earlier than they actually do. Mothers' knowledge about cognitive, language, and motor abilities was stronger than their knowledge about abilities in play and social development. Across domains, mothers were more accurate at estimating the ages of abilities that emerge in the first year than those occurring during children's second and third years. Findings are discussed with respect to societal emphases on different domains of development, and the potential implications of unrealistic expectations for adolescent parenting. ©2002 Michigan Association for Infant Mental Health.
Postneonatal mental and motor development of infants exposed in utero to opioid drugs
Authors: Hans Sydney L. , Jeremy Rita J. 
Published: August 2002

AbstractWe compared the mental and motor development of 33 infants from innercity, African American families whose mothers used opioid drugs during pregnancy with that of 45 infants from demographically comparable families where the mothers were not users of opioids. We found that during the first 2 years of life, the children exposed to opioid drugs showed poorer functioning on Bayley Scales mental and psychomotor development indices as well as on Infant Behavior Record ratings of mental and motor functioning. Although both groups of children performed in the normal range during infancy, both groups showed sharp declines in their developmental scores during the second year of life relative to norms. The poorer performance of the opioid‐exposed group in mental development was related to social‐environmental risk factors; in psychomotor development, to reduced birth weight. © 2001 Michigan Association for Infant Mental Health.
Protective action of the serine protease inhibitor N‐tosyl‐L‐lysine chloromethyl ketone (TLCK) against acute soman poisoning
Authors: Cowan F. M. , Broomfield C. A. , Lenz D. E. , Shih T.‐M. 
Published: August 2002

AbstractSoman‐poisoned rats display cholinergic crisis, a systemic mast cell degranulation characteristic of anaphylactic reactions and an excitotoxin‐like sequential seizure and neuronal degeneration. The protection of guinea pigs from soman lethality by prophylactic administration of the serine protease inhibitor suramin suggests a possible proteolytic component in soman poisoning. The present study tested the effect of N‐tosyl‐L‐lysine chloromethyl ketone (TLCK), an inhibitor of trypsin‐like serine proteases, on soman‐induced toxic signs (convulsions, righting reflex) and survival time. Nine control guinea pigs receiving 2 × LD50 (56 µg kg−1, s.c.) of soman immediately followed by a therapeutic dose of atropine sulfate (17.4 mg kg−1 i.m.) experienced severe convulsions, and 8/9 lost the righting reflex. Six of these nine animals expired within 65 min; the three remaining animals survived 24 h to termination of the experiment. When a second group of animals were given TLCK (12 mg kg−1, i.p.) 30 min prior to a 2 × LD50 soman challenge and atropine‐sulfate therapy, 5/9 experienced convulsions and only 3/9 lost the righting reflex. All nine animals survived beyond 4 h, with six surviving to 24 h. Compared with soman controls, prophylaxis with TLCK significantly prevented the loss of righting reflex (P = 0.05) and enhanced 4‐h survival (P = 0.005). Although, convulsions were reduced and 24‐h survival was improved in TLCK‐treated animals, these results were not statistically significant. The protection from soman toxicity by chemically distinct protease inhibitors such as suramin and TLCK suggests a role for pathological proteolytic pathways in soman intoxication. Copyright © 2001 John Wiley & Sons, Ltd.
On carbide dissolution in an as‐cast ASTM F‐75 alloy
Authors: Caudillo M. , Herrera–Trejo M. , Castro M. R. , Ramírez E. , González C. R. , Juárez J. I. 
Published: August 2002

AbstractThe solution treatment of an as‐cast ASTM F‐75 alloy was investigated. Microstructural evolution was followed during thermal processing, in particular with regard to the content and type of carbides formed. To evidence any probable carbide transformations occurring during the heating stage, as well as to clarify their effect on the carbide dissolution kinetics, three heating rates were studied. Image analysis and scanning electron microscopy techniques were used for microstructural characterization. For the identification of precipitates, these were electrolytically extracted from the matrix and then analyzed by X‐ray diffraction. It was found that the precipitates in the as‐cast alloy were constituted by both a M23C6 carbide and a σ intermetallic phase. The M23C6 carbide was the only phase identified in solution‐treated specimens, regardless of the heating rate employed, which indicated that this carbide dissolved directly into the matrix without being transformed first into an M6C carbide, as reported in the literature. It was found that the kinetics of dissolution for the M23C6 carbide decreased progressively during the solution treatment, and that it was sensitive to the heating rate, decreasing whenever the latter was decreased. Because the M23C6 carbide was not observed to suffer a phase transformation prior to its dissolution into the matrix, the effect of the heating rate was associated to the morphological change occurred as the specimens were heated. The occurrence of the observed phases was analyzed with the aid of phase diagrams computed for the system Co–Cr–Mo–C. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 378–385, 2002
Hydroxyapatite deposition by electrophoresis on titanium sheets with different surface finishing
Authors: Ágata de Sena Lídia , Calixto de Andrade Mônica , Malta Rossi Alexandre , de Almeida Soares Gloria 
Published: August 2002

AbstractHydroxyapatite coatings are commonly applied to metallic biomedical implants to accelerate osseointegration. These coatings, usually produced by plasma spray techniques, can be obtained by alternative processes, like biomimetic process, electrolytic deposition, or electrophoretic process as well. Electrophoretic deposition of hydroxyapatite exhibits several advantages like simplicity and low cost. In this article, titanium sheets with three different surface finishing were coated with hydroxyapatite by using electrophoresis. Surface treatments include: (1) abrading with SiC paper; (2) abrading with SiC paper plus electrolytic etch with H3PO4 solution; and (3) blasting with alumina powder followed by etch with a solution containing H2O2 and HF. Stoichiometric hydroxyapatite was used to coat titanium sheets. Blasted samples were also coated using a calcium‐deficient hydroxyapatite. SEM, XRD, and FTIR were employed to characterize titanium substrates and coatings produced. Results show that electrophoretic process can produce a uniform thin layer, satisfactorily adhered, of hydroxyapatite on treated titanium samples. Furthermore, sintering at 800 °C do not promote the decomposition of calcium‐deficient hydroxyapatite. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 1–7, 2002
Solution deposition of hydroxyapatite on titanium pretreated with a sodium ion implantation
Authors: Pham M. T. , Matz W. , Grambole D. , Herrmann F. , Reuther H. , Richter E. , Steiner G. 
Published: August 2002

AbstractTitanium surfaces were treated by exposing them to a beam of sodium ions. Sodium titanate was shown to be incorporated within the oxidic titanium surface. The ion‐implanted surfaces were examined for their reactivity by immersion in a simulated body fluid, which showed the formation of surface‐bound hydroxyapatite. The surface was characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and optical and electron microscopy. The surface hydroxyl concentration was determined using the nuclear reaction 1H(15N, αγ)12C. Surface‐related parameters that may affect hydroxyapatite nucleation are discussed in terms of the electrical double layer. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 716–724, 2002
Fluorinated surface‐modifying macromolecules: Modulating adhesive protein and platelet interactions on a polyether‐urethane
Authors: Jahangir A. R. , McClung W. G. , Cornelius R. M. , McCloskey C. B. , Brash J. L. , Santerre J. P. 
Published: August 2002

AbstractPolyether‐urethanes (PEUs) have been the materials of choice for the manufacture of conventional blood‐contacting devices. Nevertheless, biostability and blood compatibility are still among the principal limitations in their long‐term application. Studies investigating the development of protective coatings for PEUs have shown that degradation can be reduced with the use of fluorinated surface‐modifying macromolecules (SMMs). It has also been hypothesized that SMM‐modified PEU surfaces may exhibit improved blood compatibility because other studies have shown a modulation in fibrinogen adsorption onto these surfaces. To determine the blood compatibility of a PEU‐containing fluorinated SMMs, a series of in vitro experiments were designed to study the pattern of protein adsorption from plasma and then to assess the nature of platelet adhesion and activation on each substrate. Western blot analysis as well as single protein studies revealed that the dominant “adhesive proteins” [fibrinogen (Fg), fibronectin (Fnc), and vitronectin (Vnc)] were adsorbed on two of the SMM‐containing PEUs in lower amounts relative to unmodified base. Platelet adhesion and activation data further highlighted the differences among the various substrates. It was shown that the unmodified base had a higher number of adhered platelets relative to the SMM‐modified surfaces, and that of the SMM‐containing substrates, which showed the lowest levels of adhesive proteins also, exhibited significantly lower platelet densities. Close morphological examination further revealed that platelets residing on these latter substrates were not appreciably activated. Based on the current evidence, it is believed that the fluorinated SMMs demonstrate good potential for the development of surfaces with minimal thrombogenic character in in vivo applications. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 135–147, 2002
Collagen and bone viscoelasticity: A dynamic mechanical analysis
Authors: Yamashita Junro , Li Xiaoe , Furman Benjamin R. , Rawls H. Ralph , Wang Xiaodu , Agrawal C. Mauli 
Published: August 2002

AbstractThe purpose of this study was to explore the effects of changes in Type I collagen on the viscoelasticity of bone. Bone coupons were heated at either 100 or 200 °C to induce the thermal denaturation of Type I collagen. Half of these specimens were rehydrated after heat treatment; the other half were tested in a dry condition. The degree of denatured collagen (DC%) was analyzed by a selective digestion technique with the use of α‐chymotrypsin. Isothermal (37 °C) and variable temperature tests (scans from 35 to 200 °C) were performed with the use of a dynamic mechanical analyzer to evaluate changes in bone viscoelastic properties as a function of collagen damage, specifically, changes in the loss factor (tan δ) and storage modulus (E′) were assessed. Significant collagen denaturation occurred only when bone was heated at 200 °C irrespective of the hydration condition. Also, DC% did not show a significant effect on tan δ. However, higher values of tan δ were observed in wet samples compared to dry specimens. The temperature‐scan tests revealed that the hydration condition, but not DC%, significantly affected the behavior of tan δ. However, E′ was not strongly influenced either by DC% or by water content. These results suggest that at a constant frequency the denaturation of collagen triple‐helical molecules may have few effects on the viscoelasticity of bone, but moisture may play a prominent role in determining this property. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 31–36, 2002
Electrospun nanofibrous structure: A novel scaffold for tissue engineering
Authors: Li Wan‐Ju , Laurencin Cato T. , Caterson Edward J. , Tuan Rocky S. , Ko Frank K. 
Published: August 2002

AbstractThe architecture of an engineered tissue substitute plays an important role in modulating tissue growth. A novel poly(D,L‐lactide‐co‐glycolide) (PLGA) structure with a unique architecture produced by an electrospinning process has been developed for tissue‐engineering applications. Electrospinning is a process whereby ultra‐fine fibers are formed in a high‐voltage electrostatic field. The electrospun structure, composed of PLGA fibers ranging from 500 to 800 nm in diameter, features a morphologic similarity to the extracellular matrix (ECM) of natural tissue, which is characterized by a wide range of pore diameter distribution, high porosity, and effective mechanical properties. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell–matrix interaction within the cellular construct supports the active biocompatibility of the structure. The electrospun nanofibrous structure is capable of supporting cell attachment and proliferation. Cells seeded on this structure tend to maintain phenotypic shape and guided growth according to nanofiber orientation. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique architecture, which acts to support and guide cell growth. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 613–621, 2002
The influence of material and design features on the mechanical properties of transpedicular spinal fixation implants
Authors: Hahn Michael , Nassutt Roman , Delling Günter , Mahrenholtz Oskar , Schneider Erich , Morlock Michael 
Published: August 2002

AbstractThis study describes the finding and performance of mechanical strength and corrosion testing procedures for comparative examination of multiple internal transpedicular spine fixators. Seven different implant models from five different manufacturers were compared regarding their bending strength and fatigue resistance. Because of the unacceptably high levels of time and material that they require, ISO and ASTM testing standards are not applicable to comparative testing. In addition, there is a lack of knowledge about clinically defined and proven strength‐limit values. Therefore, actual standard testing procedures have been modified and extended to corrosion testing. Overall, the effort necessary to obtain reproducible comparative data has been reduced significantly. Although a reduced number of implants of each type were available for destructive testing, the results revealed fundamental differences in the tested implants between different materials and design features. During fatigue testing some of the implants showed poor corrosion properties. Because spinal fixation implants tend to be used as long‐duration implants, corrosion testing as well as comparative strength testing with clinically successful implant models should be performed as preclinical evaluations. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 354–362, 2002
Adhesion/decalcification mechanisms of acid interactions with human hard tissues
Authors: Yoshioka M. , Yoshida Y. , Inoue S. , Lambrechts P. , Vanherle G. , Nomura Y. , Okazaki M. , Shintani H. , Van Meerbeek B. 
Published: August 2002

AbstractIn order to study adhesion/decalcification mechanisms of acid interactions with human hard tissues such as bones and teeth, the chemical interaction of five carboxylic acids (acetic, citric, lactic, maleic, and oxalic) and two inorganic acids (hydrochloric and nitric) with enamel and two synthetic hydroxyapatite (HAp) powders with, respectively, a high and a low crystallinity were analyzed using X‐ray photoelectron spectroscopy (XPS), atomic absorption spectrophotometry (AAS), and spectrophotometry (S). X‐ray diffraction revealed that the crystallinity of the highly crystallized HAp was considerably higher than that of enamel while the crystallinity of the poorly crystallized HAp was similar to that of dentin and bone. XPS of acid‐treated enamel demonstrated for all carboxylic acids ionic bonding to calcium of HAp. AAS and S showed for both HAps that all carboxylic and inorganic acids except oxalic acid extracted Ca significantly more than P, leading to a Ca/P ratio close to that of synthetic HAp (2.16 w/w). Oxalic acid extracted hardly any Ca, but substantially more P, leading to a significantly smaller Ca/P ratio than that of HAp. AAS showed that the calcium salt of oxalic acid hardly could be dissolved, whereas the calcium salts of all the other acids were very soluble in their respective acid solution. These results confirm the adhesion/decalcification concept (AD‐concept) previously advanced. Depending on the dissolution rate of the respective calcium salts, acids either adhere to or decalcify apatitic substrates. It is concluded that the AD‐concept that originally dictated the interaction of carboxylic acids with human hard tissues can be extended to inorganic acids, such as hydrochloric and nitric acid. Furthermore, HAp crystallinity was found not to affect the adhesion/decalcification behavior of acids when interacting with apatitic substrates, so that the AD‐concept can be applied to all human hard tissues with varying HAp crystallinity. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 56–62, 2002
Protein adsorption and human osteoblast‐like cell attachment and growth on alkylthiol on gold self‐assembled monolayers
Authors: Scotchford Colin A. , Gilmore Christopher P. , Cooper Elaine , Leggett Graham J. , Downes Sandra 
Published: August 2002

AbstractProtein adsorption and growth of primary human osteoblasts on self‐assembled monolayers of alkylthiols on gold (SAMs) with carboxylic acid and hydroxyl and methyl termini were investigated. Single‐component SAMs and SAMs patterned by photolithographic techniques were used. Cell growth on patterned SAMs demonstrated preferences for one pattern region in all combinations of alkylthiols, with the hierarchical preference COOH > OH > CH3. Patterned SAMs and immunochemistry were used to investigate adsorption of fibronectin and albumin with respect to different alkylthiol termini. Fibronectin adsorption from both pure solution and serum containing cell culture medium (SDMEM) followed the sequence COOH > OH > CH3. Albumin adsorption from pure solution followed the sequence OH > COOH > CH3; from SDMEM the sequence was CH3 > OH > COOH. Cell attachment to SAMs with the above termini, after preadsorption with fibronectin, albumin, or mixtures of fibronectin and albumin, was measured. Attachment was maximal on COOH‐terminated SAMs precoated with fibronectin. Attachment to COOH was significantly reduced only when fibronectin was omitted from the protein preadsorption solution. On OH and CH3 SAMs increasing the proportion of albumin in the solution was sufficient to significantly reduce cell attachment. The distribution vinculin and the integrins α5β1 and αvβ3 indicated that focal contact formation by cells varied with alkylthiol termini in the following sequence: COOH > OH > CH3. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 84–99, 2002
Effect of mechanical perturbation on the release of PGE2 by macrophages in vitro
Authors: Grottkau B. E. , Noordin S. , Shortkroff S. , Schaffer J. L. , Thornhill T. S. , Spector M. 
Published: August 2002

AbstractMacrophages play numerous roles in both physiologic and pathologic processes. Along with fibroblasts, they comprise the synovial tissue that forms the lining of musculoskeletal joint capsules and bursae, and they often envelop implants. During the process of phagocytosing prosthesis‐related particles, macrophages in peri‐implant tissue release inflammatory mediators. Little is known, however, about the response of these cells to mechanical perturbation, which often is a component of the physical environment of the cell. Mouse peritoneal macrophages were grown on a flexible membrane in vitro and a dynamic 1‐Hz spatially uniform sinusoidal strain pattern imparted to the elastomeric substrate. The effect of mechanical strain on prostaglandin (PG) E2 release was evaluated using cells that were activated by lipopolysaccharide (LPS) as well as by those that were not. The results are compared with the levels of PGE2 stimulated by metallic particles. Strain magnitudes of 4 and 8% applied for 1 h resulted in almost a twofold increase in the release of PGE2 from LPS‐stimulated cells (p < 0.05) and nonstimulated macrophages (p < 0.07), compared with nonperturbated controls. No release was elicited by a challenge of metal particles. These findings demonstrate for the first time an effect of mechanical force on the release of an inflammatory mediator by macrophages. This response may help to explain the macrophage‐mediated processes underlying the osteolysis associated with loose prostheses in bone and suggests a mechanism for the inflammation of synovial tissues by excessive mechanical strain. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 288–293, 2002
Proliferation and differentiation of rat calvarial osteoblasts on type I collagen‐coated titanium alloy
Authors: Becker D. , Geißler U. , Hempel U. , Bierbaum S. , Scharnweber D. , Worch H. , Wenzel K.‐W. 
Published: August 2002

AbstractSeveral attempts have been made to improve osseointegration of titanium alloy as an implant material by modification of its surface. In the present study, proliferation, differentiation, and mineralization of osteoblasts on type I collagen‐coated Ti6Al4V were investigated. The activity of alkaline phosphatase and the accumulation of calcium by osteoblasts grown on titanium alloy were significantly higher compared to cells grown on polystyrene. Precoating of the implant surface with type I collagen did not extensively affect proliferation, the activity of alkaline phosphatase, collagen synthesis, calcium accumulation, or the mRNA levels for collagen I α1, osteopontin, osteocalcin, MMP‐2, and TIMP‐2. Maximum collagen synthesis by osteoblasts was observed at day 4 of culture independent of the type of implant material. The specific activity of alkaline phosphatase reached its maximum at day 18 of culture. Accumulation of calcium and elevated mRNA levels for osteocalcin were found at day 22. These results indicate that collagen‐coating alone is not sufficient to accelerate differentiation of rat calvarial osteoblasts on Ti6Al4V. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 516–527, 2002