bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural changes of UHMWPE after e‐beam irradiation and thermal treatment
Authors: Slouf Miroslav , Synkova Hana , Baldrian Josef , Marek Antonin , Kovarova Jana , Schmidt Pavel , Dorschner Helmut , Stephan Michael , Gohs Uwe 
Published: September 2007

AbstractUltra‐high molecular weight polyethylene (UHMWPE) was irradiated with accelerated electrons (1 MeV in air) using high dose rates (> 25 kGy/min) and thin specimens (thickness 1 mm). Parts of the specimens were remelted (200°C for 10 min; 150°C for 0, 2, 10, 30, 60 min). All specimens were stored in nitrogen in the dark at 5°C. Supermolecular structure, extent of crosslinking, oxidative degradation, and macroradical content were studied by a number of methods (SAXS, WAXS, SEM, DSC, FTIR, ESR, TGA, solubility experiments, image analysis). The results obtained with irradiated samples were compared with those obtained with irradiated and remelted samples. It was confirmed that crosslinking predominates over chain scission at very high dose rates, even if the irradiation is performed in air. Discrepancies concerning supermolecular structure changes in UHMWPE after irradiation and thermal treatment, found in various studies in the literature, are discussed. A simple model, which describes and explains all supermolecular structure changes, is introduced. An effective way of eliminating residual macroradicals in UHMWPE is proposed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Lipase‐catalyzed synthesis of butyl esters by direct esterification in solvent‐free system
Authors: Santos Júlio C , Bueno Tânia , Molgero Patrícia C , Rós Da , de Castro Heizir F 
Published: September 2007

AbstractBACKGROUND:Reactions performed under solvent‐free conditions give processes that are environmentally friendly, since most solvents are polluting agents. In this work, the performance of Candida rugosa lipae (CRL) immobilized on styrene‐divinylbenzene (STY‐DVB) or controlled pore silica (CPS), and the commercial lipase Novozym 435, was evaluated for the synthesis of butyl esters in solvent–free systems (SFS). A 22 full factorial design was used to study the influence of the organic acid chain length and the biocatalyst concentration on the esterification performance.RESULTS:When CRL on STY‐DVB was used, the ester formation was influenced by both variables and their interaction. The reaction conversion was higher (63%) using 10% of immobilized system and lauric acid, corresponding to a productivity of 3.62 g L−1 h−1 For CRL on CPS, only the effect of biocatalyst concentration was significant, and the highest yield was attained using 20% of immobilized system and caprilic acid. In the case of Novozym 435, the highest yield (49%) was obtained using butyric acid as acyl donor at 15% of immobilized lipase.CONCLUSION:The results allowed better understanding of the influence of important parameters in this environmentally friendly process, which also has the process advantage of a higher volumetric productivity when compared with a solvent system. Copyright © 2007 Society of Chemical Industry
Chondrocytes interconnecting tracks and cytoplasmic projections observed within the superficial zone of normal human articular cartilage—A transmission electron microscopy, atomic force microscopy, and two‐photon excitation microscopy studies
Authors: González Sirenia , Fragoso‐Soriano Rogelio J. , Kouri Juan B. 
Published: September 2007

AbstractThe morphology of the normal human and rat articular cartilage was assessed using transmission electron microscopy (TEM), atomic force microscopy (AFM), and two‐photon excitation (2PE) microscopy. Spurr‐embedded sections from fixed human cartilage were simultaneously evaluated using TEM and AFM. The presences of tracks among the chondrocytes from the superficial zone of the cartilage were observed. In order to ratify the presence of interconnecting tracks among superficial zone chondrocytes, whole fixed human and rat cartilage, as well as fresh whole rat cartilage, were examined under the 2PE. In all cases, these tracks were observed. In addition, porous matrix, well‐defined lacunae, and cytoplasmic projections anchored to the extracellular matrix (ECM) were also detected. We conclude that normal human and rat flattened superficial chondrocytes might be interconnected by tracks running through the ECM. In addition, cytoplasmic projections were observed anchored to the ECM. All these structures may possibly be related to cell/cell and ECM/chondrocytes signaling. Our findings provide new information that possibly will be of relevant importance for a more profound study of normal cartilage physiology and eventually, the pathogenesis of osteoarthritis. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Comparison of reflection contrast microscopy and electron microscopy on the histopathological diagnosis of various kidney diseases
Authors: Yuruker S. , Zeybek D. , Asan E. 
Published: September 2007

AbstractOur aim in this study was to compare reflection contrast microscopy (RCM) with transmission electron microscopy (TEM) to understand whether RCM could be used in the histopathological diagnosis of various kidney diseases as a less expensive and an easier alternative to TEM. The diagnoses of kidney pathologic lesions included Alport syndrome, thin membrane disease, Ig A nephropathy. RCM is a form of light microscope that works in the reflected mode, suitable to observe ultrathin (50–100 nm) plastic sections that is also used in TEM. Our findings showed that RCM showed similar results compared with TEM on these lesions described earlier. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
Optical disector counting in cryosections and vibratome sections underestimates particle numbers: Effects of tissue quality
Authors: Ward Tyson S. , Rosen Glenn D. , von Bartheld Christopher S. 
Published: September 2007

AbstractOptical disector counting is currently applied most often to cryosections, followed in frequency by resin‐embedded tissues, paraffin, and vibratome sections. The preservation quality of these embedding options differs considerably; yet, the effect of tissue morphology on numerical estimates is unknown. We tested whether different embedding media significantly influence numerical estimates in optical disector counting, using the previously calibrated trochlear motor nucleus of hatchling chickens. Animals were perfusion‐fixed with paraformaldehyde (PFA) only or in addition with glutaraldehyde (GA), or by Methacarn immersion fixation. Brains were prepared for paraffin, cryo‐, vibratome‐ or celloidin sectioning. Complete penetration of the thionin stain was verified byz‐axis analysis. Neuronal nuclei were counted using an unbiased counting rule, numbers were averaged for each group and compared by ANOVA. In paraffin sections, 906 ± 12 (SEM) neurons were counted, similar to previous calibrated data series, and results obtained from fixation with Methacarn or PFA were statistically indistinguishable. In celloidin sections, 912 ± 28 neurons were counted—not statistically different from paraffin. In cryosections, 812 ± 12 neurons were counted (underestimate of 10.4%) when fixed with PFA only, but 867 ± 17 neurons were counted when fixed with PFA and GA. Vibratome sections had the most serious aberration with 729 ± 31 neurons—a deficit of 20%. Thus, our analysis shows that PFA‐fixed cryosections and vibratome sections result in a substantial numerical deficit. The addition of GA to the PFA fixative significantly improved counts in cryosections. These results may explain, in part, the significant numerical differences reported from different labs and should help investigators select optimal conditions for quantitative morphological studies. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
Spider capture silk: performance implications of variation in an exceptional biomaterial
Authors: Swanson Brook O. , Blackledge Todd A. , Hayashi Cheryl Y. 
Published: September 2007

AbstractSpiders and their silk are an excellent system for connecting the properties of biological materials to organismal ecology. Orb‐weaving spiders spin sticky capture threads that are moderately strong but exceptionally extensible, resulting in fibers that can absorb remarkable amounts of energy. These tough fibers are thought to be adapted for arresting flying insects. Using tensile testing, we ask whether patterns can be discerned in the evolution of silk material properties and the ecological uses of spider capture fibers. Here, we present a large comparative data set that allows examination of capture silk properties across orb‐weaving spider species. We find that material properties vary greatly across species. Notably, extensibility, strength, and toughness all vary approximately sixfold across species. These material differences, along with variation in fiber size, dictate that the mechanical performance of capture threads, the energy and force required to break fibers, varies by more than an order of magnitude across species. Furthermore, some material and mechanical properties are evolutionarily correlated. For example, species that spin small diameter fibers tend to have tougher silk, suggesting compensation to maintain breaking energy. There is also a negative correlation between strength and extensibility across species, indicating a potential evolutionary trade‐off. The different properties of these capture silks should lead to differences in the performance of orb webs during prey capture and help to define feeding niches in spiders. J. Exp. Zool. 307A:654–666, 2007. © 2007 Wiley‐Liss, Inc.
Modulation of brain metabolism by very low concentrations of the commonly used drug delivery vehicle dimethyl sulfoxide (DMSO)
Authors: Nasrallah Fatima A. , Garner Brett , Ball Graham E. , Rae Caroline 
Published: September 2007

AbstractDimethyl sulfoxide (DMSO) has long been used in studies as a vehicle to enhance the solubility and transport of ligands in biological systems. The effects of this drug on the outcomes of such studies are still unclear, with concentrations of DMSO reported as “safe” varying considerably. In the present work, we investigated the effects of very low concentrations of DMSO on the brain metabolism of [3‐13C]pyruvate and D‐[1‐13C]glucose using 1H/13C NMR spectroscopy and a guinea pig cortical brain slice model. Our results show that DMSO is accumulated by brain slices. DMSO at all concentrations [0.000025%–0.25% (v/v)] increased the metabolic rate when [3‐13C]pyruvate was used as a substrate and also in the presence of D‐[1‐13C]glucose (0.00025%–0.1% DMSO). These results are consistent with DMSO stimulating respiration, which it may do through altering the kinetics of ATP‐requiring reactions. Our results also emphasize that there is no practical concentration of DMSO that can be used in metabolic experiments without effect. Therefore, care should be taken when evaluating the actions of drugs administered in combination with DMSO. © 2007 Wiley‐Liss, Inc.
The social identity and social networks of ethnic minority groups in organizations: a crucial test of distinctiveness theory
Authors: Leonard Ana Sierra , Mehra Ajay , Katerberg Ralph 
Published: September 2007

AbstractDistinctiveness theory posits that patterns of social identity and friendship are based on numeric rarity within specific contexts. In ethnically diverse organizations, the theory predicts that members of the smaller ethnic group (relative to members of the larger ethnic group) will: (a) tend to identify and form friendships within their own ethnic group, and (b) lack access to well‐connected individuals in the network of friendship relations. Prior tests have supported these predictions, but they have been unable to rule out the possibility that it was chronic differences in social status and numeric representation in society at large (rather than numeric distinctiveness within specific contexts) that explained the observed patterns of social identity and friendship. In this field‐based study, we examined an organization whose social composition effectively controlled for these confounds. We found that members of the smaller ethnic group tended to identify and form friendships within group, as predicted by distinctiveness theory. However, in contrast to previous work, we found that members of the smaller ethnic group were equally well connected to the center of the friendship network as were the members of the larger ethnic group. Copyright © 2007 John Wiley & Sons, Ltd.
Is cultured tendon fibroblast a good model to study tendon healing?
Authors: Fu Sai‐Chuen , Cheuk Yau‐Chuk , Chan Kai‐Ming , Hung Leung‐Kim , Wong Margaret Wan‐Nar 
Published: September 2007

AbstractCultured tendon fibroblasts (CTFs) from intact explants are widely used to study tendon healing in vitro. The significance of these findings may rely on similarities between CTFs and healing tendon fibroblasts in situ. Our purpose was to compare CTFs with fibroblasts cultured from healing tendons. We cultured CTFs from intact and healing tendons at day 7 and day 14 postinjury in a rat model of patellar donor site injury. The mRNA expression of COL1A1, COL3A1, decorin, and biglycan, with or without supplementation of 1 ng/mL TGF‐β1, was compared by quantitative real‐time RT‐PCR. The expression of proliferation cell nuclear antigen (PCNA) and α‐smooth muscle actin (α‐SMA) was determined by immunostain. COL3A1 and decorin mRNA in CTFs was lower as compared to day 7 healing fibroblasts, but its biglycan mRNA level was higher than day 14 healing fibroblasts. TGF‐β1 increased COL1A1 and decorin mRNA in CTFs, but decreased the mRNA of all four genes in day 7 healing tendon fibroblasts. CTFs exhibited lower PCNA immunopositivity as compared to day 7 and day 14 healing fibroblasts, but a higher α‐SMA immunopositivity than cultured day 14 healing fibroblasts. These findings showed that CTFs did not resemble healing tendon cells with respect to major cellular activities related to tendon healing. Thus, fibroblasts from healing tendon may be a more appropriate model for studying cellular activities in tendon healing. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:374–383, 2008
Microstructural adaptation in trapezial bone due to subluxation of the thumb
Authors: Nufer Philipp , Goldhahn Jörg , Kohler Thomas , Kuhn Volker , Müller Ralph , Herren Daniel B. 
Published: September 2007

AbstractAlthough the thumb saddle is one of the most common sites of degenerative osteoarthritis in the hand, little is known about the altered microstructure in osteoarthritic trapezial bones. External forces resulting from subluxation of the carpometacarpal joint of the thumb (CMC I) should provoke microstructural changes in the trapezium. The purpose of this study was to compare the regional differences of the microstructure between osteoarthritic and healthy trapezial bones. Fifteen trapezia harvested from female patients with radiologically and clinically diagnosed saddle joint osteoarthritis (OA) were compared with 15 unaffected controls. Microstructural parameters, such as bone volume ratio (BV/TV), three‐dimensional connectivity (Conn.D), trabecular number (Tb.N), and trabecular thickness (Tb.Th) were studied using a microcomputed tomography (microCT) system. While the trapezial height in OA was 22% less, the sclerotic subchondral bone layer thickness was 50% higher in OA compared with the control group (p < 0.001). In the OA group there was a 42% higher bone volume ratio (p ≤ 0.001), an 18% increase in Tb.Th (p = 0.006), and a 10% greater Tb.N (p = 0.034) compared with the control group. Although in both groups BV/TV was significantly lower in the radial region, the radial column showed the highest relative increase in bone volume and structure compared with the control group (+67% BV/TV, +20% Tb.Th, +23% Tb.N). The reinforcement of the bony microstructure in CMC I OA, especially at the radial side, is a sign for bone adaptation reacting to radially shifted joint forces. This has to be considered during the development of new prosthetic alternatives. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:208–216, 2008
Binary chromatographic fingerprinting for quality evaluation of Radix Ophiopogonis by high‐performance liquid chromatography coupled with ultraviolet and evaporative light‐scattering detectors
Authors: Liu Li , Lu Yun , Shao Qing , Cheng Yi‐Yu , Qu Hai‐Bin 
Published: September 2007

AbstractRadix Ophiopogonis is a widely used traditional Chinese medicine. The quality of Radix Ophiopogonis available in the market varies, and some confusing or fake herbs exist. In order to improve the quality control of Radix Ophiopogonis, a novel fingerprinting method was established using HPLC coupled with UV and evaporative light‐scattering detectors (ELSDs). Extraction with methanol and liquid–liquid extraction with water‐saturated n‐butanol were employed for the preparation of the sample solution. Chromatographic separation was performed on a Lichrospher C18 column (250×4.6 mm id, 5.0 μm particle size) with a linear gradient elution program. UV detection at 280 nm and evaporative light‐scattering detection were utilized to obtain two subfingerprinting chromatograms. A novel protocol for data processing was proposed, in order to identify and remove redundant data obtained by the two detectors, and balance the weight of the two subfingerprints on the similarity values. The method was validated and applied to quality evaluation of 16 samples of Radix Ophiopogonis and related herbs.
Kinetics of the reactions of C2H5, n‐C3H7, and n‐C4H9 radicals with Cl2 at the temperature range 190–360 K
Authors: Eskola Arkke J. , Lozovsky Vladimir A. , Timonen Raimo S. 
Published: September 2007

AbstractThe kinetics of the C2H5 + Cl2, n‐C3H7 + Cl2, and n‐C4H9 + Cl2 reactions has been studied at temperatures between 190 and 360 K using laser photolysis/photoionization mass spectrometry. Decays of radical concentrations have been monitored in time‐resolved measurements to obtain reaction rate coefficients under pseudo‐first‐order conditions. The bimolecular rate coefficients of all three reactions are independent of the helium bath gas pressure within the experimental range (0.5–5 Torr) and are found to depend on the temperature as follows (ranges are given in parenthesis): k(C2H5 + Cl2) = (1.45 ± 0.04) × 10−11 (T/300 K)−1.73 ± 0.09 cm3 molecule−1 s−1 (190–359 K), k(n‐C3H7 + Cl2) = (1.88 ± 0.06) × 10−11 (T/300 K)−1.57 ± 0.14 cm3 molecule−1 s−1 (204–363 K), and k(n‐C4H9 + Cl2) = (2.21 ± 0.07) × 10−11 (T/300 K)−2.38 ± 0.14 cm3 molecule−1 s−1 (202–359 K), with the uncertainties given as one‐standard deviations. Estimated overall uncertainties in the measured bimolecular reaction rate coefficients are ±20%. Current results are generally in good agreement with previous experiments. However, one former measurement for the bimolecular rate coefficient of C2H5 + Cl2 reaction, derived at 298 K using the very low pressure reactor method, is significantly lower than obtained in this work and in previous determinations. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 614–619, 2007
Ab initio calculations of carbon‐containing species and comparison with group additivity results: Part I. C5 species
Authors: Burcat Alexander 
Published: September 2007

AbstractTwenty‐six C5 compounds and radicals related to combustion processes have been calculated using the ab initio G3//B3LYP method using the atomization enthalpy analysis. The results have been compared to group additivity estimates and literature values where available. Three different group additivity programs were used, and results concerning the comparison are given. The NIST 94 program is more reliable than the other two. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 620–628, 2007
Efficacy of early treatment of facial port wine stains in newborns: A review of 49 cases
Authors: Chapas Anne M. , Eickhorst Kimberly , Geronemus Roy G. 
Published: September 2007

AbstractBackgroundPort wine stains (PWS) affect 0.3–0.5% of both sexes of newborns, usually occurring on the face.ObjectiveTo document safety and effectiveness of cryogen spray cooled, pulsed‐dye laser at higher fluences than previously used to lighten facial PWS in infants ≤6 months, and establish that frequent treatment early in life yields better clearance than if delayed until later in life.Materials and MethodsForty‐nine infants who had been treated with pulsed‐dye laser treatments for facial PWS at ≤6 months were identified by case review of photographs, age, sex, PWS severity score prior to laser treatment, number of treatments, and improvement following laser therapy.ResultsPatients averaged 9.3 (range 2–16) treatments at 4–6 week intervals at 7.75–9.5 J/cm2. Average surface area treated was 24.0% with 88.6% average clearance after 1 year. Average clearance was 90.7% for lesions covering <20% surface area and 85.6% for lesions ≥20%. Location (V1, V2, V3, eye, and/or scalp), treated surface area, treatment number, and fluence predicted clearance. Average clearance for sole involvement of V1 was highest (at 93.8%), followed by V2 (at 91.1%), V3 (at 84.3%), V1/V2 (at 83.7%), V1/V2/V3 (at 81.0%), periocular (at 88.6%), and scalp (at 89.9%). All patients tolerated the higher treatment fluences without atrophy or scarring.Discussion/ConclusionsFrequent, high energy pulsed‐dye laser treatments are safe and highly effective in improving facial PWS in infants ≤6 months of age. Patients with PWS should be referred for pulsed‐dye laser treatment during early infancy. Lesers Surg. Med. 39:563–568, 2007. © 2007 Wiley‐Liss, Inc.
Propagation Rate Coefficient and Fraction of Mid‐Chain Radicals for Acrylic Acid Polymerization in Aqueous Solution
Authors: Buback Michael , Hesse Pascal , Lacík Igor 
Published: September 2007

AbstractIn acrylate polymerizations both SPRs and tertiary MCRs occur. Via pulsed laser polymerization, using a wide range of LPRRs, in conjunction with aqueous‐phase size‐exclusion chromatography, the polymerization of 1.35 mol · L−1 acrylic acid in aqueous solution has been investigated at 6 °C. The sigmoidal decrease in the apparent propagation rate coefficient, k, towards lower LPRRs is in line with recent predictions. At the highest LPRRs, k approaches the rate coefficient of SPR propagation, k, whereas the limiting value of k at low LPRRs approaches the effective propagation rate coefficient, k, which allows for an estimate of the fraction of MCRs under polymerization conditions, xMCR.magnified image
Effective Drug Therapies from Functional, Macromolecular Building Blocks with a Biomimetic Design
Authors: Huang Kui , Croce Teresa A. , Hamilton Sharon K. , Adkins Chinessa T. , Evans Billie L. , Harth Eva 
Published: September 2007

AbstractSummary: The development of suitable delivery systems for intracellular delivery of proteins, peptides and other bioactive materials opens the possibility to establish refined strategies for small drug delivery, gene delivery and vaccination. We present the assembly of advanced drug delivery systems from tailored building blocks to scaffolds and bioactive cargos to afford targeting and transport across biological barriers. In particular, the utilization of novel molecular transporter will advance the bioavailability of small and macromolecular drugs that show targeted intracellular delivery.