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Selected AbstractsK-Ras and microsatellite marker analysis of fine-needle aspirates from intraductal papillary mucinous neoplasms of the pancreas,DIAGNOSTIC CYTOPATHOLOGY, Issue 9 2006Karen E. Schoedel M.D. Abstract Preoperative diagnosis of pancreatic cystic lesions is difficult despite the combination of cytomorphology, radiographic imaging characteristics, and fluid tumor markers such as carcinoembryonic antigen. Intraductal papillary mucinous neoplasms (IPMNs) represent a subset of preinvasive pancreatic cystic neoplasms and are associated with accumulated genetic mutations, especially K-ras and tumor suppressor genes such as p53. Application of molecular techniques to cyst fluid obtained by endoscopic ultrasound guided fine-needle aspiration (EUSFNA) may contribute to preoperative assessment. Sixteen patients with pancreatic cystic lesions had cyst fluid obtained by preoperative pancreatic EUSFNA or intraoperative aspiration. All patients subsequently underwent surgical resection of the pancreas and IPMN was documented in all (6 adenomas, 6 borderline tumors, and 4 carcinomas). DNA was extracted from the cyst fluids and mutational analysis for K-ras point mutations and loss of heterozygosity (LOH) analysis using a preselected panel of genomic loci were performed. LOH was observed in 3 of 4 carcinomas as compared to 4 of 11 adenomas and borderline lesions (1 was QNS). LOH and K-ras mutations were both acquired in 2 of 4 carcinomas and in 1 of 12 adenoma/borderline lesions. Although the study is small, molecular analysis for LOH and K-ras mutations is useful in the preoperative evaluation of cystic pancreatic lesions. Increasing degree of neoplasia appears to correlate with increased genetic abnormality using a panel of selected genomic markers. Diagn. Cytopathol. 2006;34:605,608. © 2006 Wiley,Liss, Inc. [source] Cross-Linking and Degradation Properties of Plasma Enhanced Chemical Vapor Deposited Poly(2-hydroxyethyl methacrylate)MACROMOLECULAR RAPID COMMUNICATIONS, Issue 2 2009Courtney A. Pfluger Abstract Plasma Enhanced Chemical Vapor Deposition (PECVD) of poly-2-hydroxyethyl methacrylate (pHEMA) biocompatible, biodegradable polymer films were produced alone and cross-linked with ethylene glycol diacrylate (EGDA). Degree of cross-linking was controlled via manipulation of the EGDA flow rate, which influenced the amount of swelling and the extent of degradation of the films in an aqueous solution over time. Noncross-linked pHEMA films swelled 10% more than cross-linked films after 24 h of incubation in an aqueous environment. Increasing degree of film cross-linking decreased degradation over time. Thus, PECVD pHEMA films with variable cross-linking properties enable tuning of gel formation and degradation properties, making these films useful in a variety of biologically significant applications. [source] Prevalence of diabetes and/or ischaemic heart disease in classes of increasing carotid artery atherosclerosis: an ultrasonographic studyDIABETIC MEDICINE, Issue 8 2003S. Inchiostro Abstract Aims To evaluate the prevalence of non-diabetic subjects and diabetic patients, with or without ischaemic heart disease (IHD), in different classes of increasing carotid atherosclerotic damage. Methods Using high-resolution B-mode ultrasound, we studied 598 subjects without known cardiovascular disease (CVD) or diabetes, 74 diabetic patients without CVD, 74 non-diabetic subjects with IHD and 36 patients with both diabetes and IHD. Carotid atherosclerosis was classified as: normal; thickened intima-media; non-stenotic plaque; stenotic plaque. Results Compared with subjects without diabetes or CVD, the frequency of patients with diabetes without known CVD increased significantly from ,normal' to ,stenotic plaque' (4.1%, 6.4%, 13%, 14.8% for normal, thickened intima-media, non-stenotic plaque and stenotic plaque, respectively; P = 0.0057). The same figures were 6%, 7.6%, 10.2%, 23.3% (P = 0.0007) for non-diabetic subjects with IHD, and 0%, 2%, 5.6%, 15.9% (P < 0.0001) for diabetic patients with IHD. No difference was found comparing subjects with diabetes without CVD with non-diabetic patients with IHD (P = 0.56). Using polychotomous logistic regression analysis, diabetic patients without CVD and non-diabetic subjects with IHD showed a similar association with the increasing degree of carotid atherosclerosis (P = 0.59), but significantly stronger compared with subjects without diabetes or CVD (P < 0.03 for both). Conclusions Diabetic patients without known CVD show an advanced degree of carotid atherosclerotic damage similar to non-diabetic subjects with IHD and significantly higher compared with non-diabetic subjects without CVD. Our data support the need for an aggressive early prevention of CVD in diabetic subjects. [source] ,-Cyclodextrin as novel chiral probe for enantiomeric separation by electromigration methodsELECTROPHORESIS, Issue 21 2006Dorothee Wistuba Abstract Native ,-CD has been employed as chiral selector in CE and MEKC. To investigate the potential of the enantiodiscriminating properties of ,-CD, negatively charged 5-dimethylamino-1-naphthalene-sulfonyl (dansyl)-, 2,4-dinitrophenyl (DNP)- and FMOC-derivatives of several amino acids, 1,1'-binaphthyl-2,2'-diylhydrogenphosphate, flavanones and three positively charged drugs have been selected as testing samples. Enantioresolution factors up to 4.82 have been observed. The results were compared with those achieved by the conventional running buffer additives ,-, ,- and ,-CDs. For several examples a steady increase of enantioresolution with increasing degree of oligomerization has been detected. [source] Acute toxicity of (chloro-)catechols and (chloro-)catechol-copper combinations in Escherichia coli corresponds to their membrane toxicity in vitroENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2001Nina Schweigert Abstract (Chloro-)catechols are toxic for bacteria and higher organisms, but the mode of action is not yet clearly understood. We have compared the acute toxicity of different chlorinated catechols to Escherichia coli with membrane toxic effects, namely narcosis and uncoupling that we have determined in an in vitro assay. In vitro membrane toxicity was quantified by measuring the accelerated decay of the membrane potential of chromatophores isolated from Rhodobacter sphaeroides. Both acute and membrane toxicity increased with increasing degree of chlorination. Analysis of dose-response curves, pH dependence, and estimated membrane concentrations gave a consistent picture of the mechanisms of membrane toxicity: At pH 7, the higher-chlorinated catechols acted as uncouplers of oxidative and photophosphorylation, and the lower-chlorinated catechols and catechol acted as narcotics. In the case of 3,5-dichlorocatechol and 4-monochlorocatechol at pH 8.8, both mechanisms appeared to contribute to the overall toxicity. Copper exhibited a diverging effect on the toxicity of catechols and of (chloro-)catechols to E. coli. Whereas the presence of copper increased the toxicity of catechol and 4-monochlorocatechol, the toxicity of 3,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol decreased. Again, the results obtained with in vitro assays agreed with the acute toxicity observed in E. coli: The presence of copper accelerated decay of the membrane potential of catechol and 4-monochlorocatechol; however, the effect was reversed by copper in experiments with 3,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol. We have proposed a mechanistic model to explain the diverging effects of copper on the uncoupling activities of the different catechols. [source] Characterization and mode of action of an exopolygalacturonase from the hyperthermophilic bacterium Thermotoga maritimaFEBS JOURNAL, Issue 21 2005Leon D. Kluskens An intracellular pectinolytic enzyme, PelB (TM0437), from the hyperthermophilic bacterium Thermotoga maritima was functionally produced in Escherichia coli and purified to homogeneity. PelB belongs to family 28 of the glycoside hydrolases, consisting of pectin-hydrolysing enzymes. As one of the few bacterial exopolygalacturonases, it is able to remove monogalacturonate units from the nonreducing end of polygalacturonate. Detailed characterization of the enzyme showed that PelB is highly thermo-active and thermostable, with a melting temperature of 105 °C and a temperature optimum of 80 °C, the highest described to date for hydrolytic pectinases. PelB showed increasing activity on oligosaccharides with an increasing degree of polymerization. The highest activity was found on the pentamer (1000 U·mg,1). In addition, the affinity increased in conjunction with the length of the oligoGalpA chain. PelB displayed specificity for saturated oligoGalpA and was unable to degrade unsaturated or methyl-esterified oligoGalpA. Analogous to the exopolygalacturonase from Aspergillus tubingensis, it showed low activity with xylogalacturonan. Calculations on the subsite affinity revealed the presence of four subsites and a high affinity for GalpA at subsite +1, which is typical of exo-active enzymes. The physiological role of PelB and the previously characterized exopectate lyase PelA is discussed. [source] Temperature sensitivity and substrate quality in soil organic matter decomposition: results of an incubation study with three substratesGLOBAL CHANGE BIOLOGY, Issue 6 2010J. Å. MARTIN WETTERSTEDT Abstract Kinetic theory suggests that the temperature sensitivity of decomposition of soil organic matter should increase with increasing recalcitrance. This ,temperature,quality hypothesis' was tested in a laboratory experiment. Microcosms with wheat straw, spruce needle litter and mor humus were initially placed at 5, 15 and 25 °C until the same cumulative amount of CO2 had been respired. Thereafter, microcosms from each single temperature were moved to a final set of incubation temperatures of 5, 15 and 25 °C. Straw decomposed faster than needle litter at 25 and 15 °C, but slower than needle litter at 5 °C, and showed a higher temperature sensitivity (expressed as Q10) than needle litter at low temperatures. When moved to the same temperature, needle litter initially incubated at 5 and 15 °C had significantly higher respiration rates in the final incubation than litters initially placed at 25 °C. Mor humus placed at equal temperatures during the initial and final incubations had higher cumulative respiration during the final incubation than humus experiencing a shift in temperature, both up- and downwards. These results indicate that other factors than substrate quality are needed to fully explain the temperature dependence. In agreement with the hypothesis, Q10 was always higher for the temperature step between 5 and 15 °C than between 15 and 25 °C. Also in agreement with the temperature,quality hypothesis, Q10 significantly increased with increasing degree of decomposition in five out of the six constant temperature treatments with needle litter and mor humus. Q10s for substrates moved between temperatures tended to be higher than for substrates remaining at the initial temperature and an upward shift in temperature increased Q10 more than a downward shift. This study largely supports the temperature,quality hypothesis. However, other factors like acclimation and synthesis of recalcitrant compounds can modify the temperature response. [source] Neurodevelopmental impairment: Predictors of its impact on the families of extremely low birth weight infants at 18 months,INFANT MENTAL HEALTH JOURNAL, Issue 6 2008Bonnie E. Stephens Effects on a family of a child with chronic illness have been described. The Impact on Family Scale (IOF) was developed to measure these effects. The impact of extremely low birth weight (ELBW) infants with neurodevelopmental impairment on families is unknown. This study determined IOF scores for families of ELBW infants with increasing degree of impairment at 18 months and identified factors that increase vulnerability to impact. A total of 3,849 ELBW infant survivors born at the 16 centers of the National Institute of Child Health and Human Development Neonatal Research Network between January 1993 and February 2001 were assessed at 18 to 22 months. Infants were divided into four groups by degree of impairment. IOF scores were analyzed by impairment group. Multivariate analyses assessed effects of impairment, social/demographic factors, unmet service needs, and resource utilization on the IOF. A total of 1,624 (42.2%) infants had moderate/severe impairment. Increasing severity of impairment was associated with higher IOF scores. Severity of impairment contributed 6% of variance to the IOF scores. Twenty-one percent of variance was contributed by additional medical needs, low socioeconomic status (SES), and lack of social support. Although increasing severity of impairment impacts families of ELBW infants, significantly more impact is contributed by additional medical needs, low SES, and lack of social support. [source] Distribution of acrylic acid grafted chains introduced into polyethylene film by simultaneous radiation grafting with water and ethanol as solventsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Zhengchi Hou Abstract The graft copolymerization of acrylic acid onto low-density polyethylene films by simultaneous ,-ray irradiation was carried out. The effect of water and ethanol as grafting solvents on the distribution of grafted poly (acrylic acid) in the low-density polyethylene films was studied with optical microscopy observations of dyed and sliced samples and attenuated total reflection/Fourier infrared spectroscopy analysis. When no vigorous homopolymerization occurred, both polyethylene and poly(acrylic acid) existed in the grafted layer, and the thickness of the grafted layer and the poly(acrylic acid) concentration in the grafted layer increased with an increasing degree of grafting, regardless of the grafting conditions, the former increasing faster than the latter. In comparison with water as the solvent, in the absence of the inhibitor, homopolymerization could be suppressed to a certain degree in the ethanol solvent system, whereas in the presence of the inhibitor, obvious homopolymerization occurred at a lower monomer concentration, and both the degree of grafting and the thickness of the grafted layer were lower. Such differences could be explained by the chain transfer and the relatively low solubility of poly(acrylic acid) in ethanol. In addition, an experimental scheme using optical microscopy to observe the dyed and sliced polymers was optimized. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1570,1577, 2007 [source] Crystallization of Lead Niobate Glass by Mechanical ActivationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2001Junmin Xue Mechanical activation-triggered crystallization in PbNb2O6 -based glass was dependent on the initial presence of nuclei. The crystallization cannot be initiated by mechanical activation in a highly amorphous glass composition quenched from 1350°C where PbNb2O6 nuclei did not exist. The steady growth of nanocrystallites of PbNb2O6 was observed with an increasing degree of mechanical activation in the glass quenched from 1300°C, where a density of PbNb2O6 nuclei existed before mechanical activation. The inability to nucleate in the highly amorphous oxide glass by mechanical activation is consistent with the much higher structural stability as compared with that of metallic glasses, such as Fe-Si-B. The mechanical activation-grown PbNb2O6 nanocrystals were 10,15 nm in size as observed using HRTEM and their crystallinities were further improved by thermal aging at an elevated temperature in the range of 550° to 650°C. [source] Improved Resistance to Damage of Silicon Carbide-Whisker-Reinforced Silicon Nitride-Matrix Composites by Whisker-Oriented AlignmentJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2001Chang-an Wang The effects of whisker-oriented alignment on resistance to damage of SiC(w)/Si3N4 composites have been investigated by the Vickers indentation method and R -curve behavior. It is shown that increasing the degree of whisker-oriented alignment decreases the lengths of Vickers impressions and indentation cracks. The results exhibit rising R -curve behaviors for the SiC(w)/Si3N4 composites with different degree of whisker-oriented alignment. Moreover, the initial crack length ci, the threshold of crack growth resistance Ki, and the upper bound of crack growth resistance K, change regularly with increasing degree of whisker-oriented alignment. All results suggest that the whisker-oriented alignment improves the resistance to damage of the composites, resulting in a more reliable and usable composite. [source] Poly(acrylamide- co -itaconic acid) and Semi-IPNS with Poly(ethylene glycol): Preparation and CharacterizationMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2004Melina Kalagasidis Kru Abstract Summary: A pH-responsive poly(acrylamide- co -itaconic acid) (PAAm/IA) hydrogel and semi-interpenetrating networks (semi-IPNs) with 5, 10 and 15 wt.-% of poly(ethylene glycol) (PAAm/IA/PEG), were synthesized. Their swelling behavior was studied in the pH range from 1.76 to 7.81, as well as their oscillatory swelling behavior at pH,=,7.81 and pH,=,1.7. Throughout these studies, the gels maintained their mechanical strengths and shape. The shear storage (G,) and loss (G,) moduli, obtained as a function of frequency, for the gels as formed and at equilibrium swelling were higher for the semi-IPNs than for the copolymer hydrogel. The shear storage moduli of copolymer hydrogel and semi-IPNs as formed were independent of frequency over the whole experimental range, whereas the values for the gels at equilibrium swelling decreased with increasing degree of swelling, i.e., the PAAm/IA hydrogel which exhibited the largest swelling had the lowest G, value. The G, and G, values also depended on the content of PEG. Diffusion exponent vs. pH for PAAm, copolymer hydrogel PAAm/IA and semi-IPN with PEG. [source] Cationic Polymerization of 2-Vinylthiophene by Chloroarylmethanes as Surface Initiators on Silica and Consecutive Hydride Abstraction by AcceptorsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 12 2004Susanne Höhne Abstract Summary: 2-Vinylthiophene (2-VT) has been cationically polymerized using chloroarylmethane derivatives as the surface polymerization initiator on silica. By applying this procedure a soluble fraction of poly(vinylthiophene) (PVT) and PVT/silica composites can be simultaneously synthesized. The mass balance of the products (soluble fraction and hybrid particle fraction) depends significantly on temperature and 2-VT/silica ratio. The hydride abstraction reaction of PVT both in solution and immobilized on silica particle surface has been studied using 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ), tetrachloro-1,4-quinone (chloranile,=,ClA) and triphenylmethylium as reagents. The transformation process of PVT towards conjugated polymers has been studied with UV-vis spectroscopy and ESR spectroscopy. Cyclic voltammetry shows that chloranil is complexated with the formed polymer. Radical formation increases with increasing degree of conversion. The soluble fraction of the conjugated PVT sections formed is capable of reacting with each other as evidenced by GPC data. Structure of PVT/silica and resulting hybrid materials have been investigated by solid state 13C {1H} CP MAS NMR-spectroscopy showing a reaction of methine and methylene hydrogen atoms after treatment with DDQ or chloranil as hydride acceptors. For all poly-(2-vinylthiophene)/hydride acceptor systems studied, chloranil has been found to be the best reagent for the transformation of PVT towards conjugated polymers. Transformation of PVT in poly(2-ethinylthiophene) (PET) and PVT-PET copolymers. [source] Geometries and Electronic Structures of Co-Oligomers and Co-Polymers Based on Tricyclic Nonclassical Thiophene: A Theoretical StudyMACROMOLECULAR THEORY AND SIMULATIONS, Issue 7-8 2008Yangwu Fu Abstract The geometries and electronic properties of four copolymers based on tricyclic nonclassical thiophene were studied using DFT at the B3LYP/6-31G(d) level. Bond lengths and their alternation, electron densities at BCPs, NICS, and WBIs were analyzed and correlated with the energy gap. The results show that the degree of conjugation increases upon main chain extension. The energy gap decreased steadily with increasing degree of polymerization. Conjugation is stronger in the central than in the outer section. The results suggest that the narrow HOMO/LUMO separation of tricyclic nonclassical thiophenes can be carried over to their co-polymers by using them as building blocks for the co-polymers. [source] Packaging materials for fermented milk: effects of material crystallinity and polarity on food qualityPACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2001S. E. A. Jansson Abstract The ability of a packaging material to protect the food product and extend its shelf-life depends on several material properties. In this work the effects of material crystallinity and polarity on the quality of fermented milk were studied. The fermented milk is a high-quality Swedish product, similar to yoghurt. The quality of the food product was determined as a function of storage time by containing the liquid in pouches of different materials. The material crystallinity was varied by using very low-density polyethylene, high-density polyethylene and aluminium laminate as packaging materials. Aluminium was used on account of its ,100%' gas-tightness. The polarity was varied by comparing an aliphatic polyketone with polyethylene of similar crystallinity. The carbon dioxide (CO2) and oxygen (O2) contents in the headspace of the pouches were determined. The food quality was determined by measuring whey syneresis, viscosity and the content of desired Bifidobacteria, as well as of undesired yeast and mould. A trained taste panel determined the degree of acidity and of the sparkling taste. It was found that the content of CO2 increased and that of O2 decreased in the pouches with increasing degree of crystallinity and increasing polarity. The sparkling taste of fermented milk was a clear function of the headspace CO2 content. The data presented here could thus be used to ,design' a package for a desired sparkling taste of the fermented milk by selecting a certain material crystallinity. Whey syneresis, viscosity and content of Bifidobacteria were found to be independent of pouch material. While the degree of whey syneresis and the viscosity increased with increasing storage time, the content of Bifidobacteria slowly decreased. The content of yeast and mould in the liquid was below the existing limit values for foodstuffs. The degrees of acidity and sparkling taste were highest for the liquids contained in aluminium and polyketone pouches, although the differences in acidulous taste between the various pouch materials were small. Copyright © 2001 John Wiley & Sons, Ltd. [source] Unionisation structures and innovation incentives*THE ECONOMIC JOURNAL, Issue 494 2004Justus Haucap This paper examines how different unionisation structures affect firms' innovation incentives and industry employment. We distinguish three modes of unionisation with increasing degree of centralisation: (1) ,decentralisation' where wages are determined independently at the firm-level, (2) ,coordination' where one industry union sets individual wages for all firms and (3) ,centralisation' where an industry union sets a uniform wage rate for all firms. While firms' investment incentives are largest under ,centralisation', investment incentives are non-monotone in the degree of centralisation: ,decentralisation' carries higher investment incentives than ,coordination'. Labour market policy can spur innovation by decentralising unionisation structures or through non-discrimination rules. [source] Mesenteric transection decreases expression of interstitial cells of Cajal in an experimental modelBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 4 2007M. Nishimura Background: After anterior resection for rectal carcinoma patients often complain of defaecatory dysfunction. The aim of this study was to examine the number of interstitial cells of Cajal (ICCs) and ganglion cells in the distal colon partially denervated by mesenteric transection in a rat model. Methods: Four groups of rats were operated on, a control group and three experimental groups, with increasing degree of mesenteric transection to denervate the distal colon. Animals were killed after 3 months, and the denervated colon was investigated using immunohistochemistry with Kit and protein gene product 9.5 antibodies to detect ICCs and ganglion cells respectively. Reverse transcriptase,polymerase chain reaction for c-kit and histomorphometry of muscular thickness were performed. Results: The total number of ICCs was significantly lower in the three operated models than in the control, particularly in the histological layers of the myenteric plexus and submucosal border. There was no difference in the number of ganglion cells or changes in muscular thickness between the models. Conclusion: The number of ICCs in rat distal colon denervated by mesenteric transection is decreased at 3 months after surgery. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Experimental Study on the Molecular Dimension and Configuration of Polymer and Its Flow Characteristics from Electrolyte EffectCHINESE JOURNAL OF CHEMISTRY, Issue 4 2009Xiangguo LU Abstract Molecular clew dimension and configuration of polymer, and flow characteristics of polymer solution were studied from electrolyte effect, by making use of dynamic light scattering (DLS), scanning electron microscopy (SEM), apparent viscosity method and core flow experiment. It can be observed that with the electrolyte concentration increasing, there exists a variation trend of "decreasing, increasing and decreasing again" to the molecular clew dimension of the polymer. The compression action of Ca2+ or Mg2+ to the double electrode layer of polymer molecules is more powerful by comparison against Na+, which results in that Ca2+ and Mg2+ have a more extensive effect on the viscosity of polymer solution, and clew dimensions and their distribution. With the electrolyte concentration increasing, the polymer molecular configuration of multi-layer stereoscopic random reticulation transformed into a dendritic one. During the succeeding water flooding, the variation degree of injection pressure of core was mainly determined by the swelling extent of molecular clew of retained polymer and the produced amount of polymer. And the bigger the molecular weight of polymer is, the stronger the compression or swelling action of electrolyte to the molecule clews is, and the greater the increasing degree of injection pressure during succeeding water flooding is. The greater difference of electrolyte concentrations in used water between polymer flooding and succeeding water flooding can result in greater increasing degree of injection pressure during the succeeding water flooding. So, an advisable increasing in difference of electrolyte concentrations in used water between the polymer flooding and succeeding water flooding was proposed when designing the polymer flooding performance in oilfields, which has promising result for improving effect of polymer flooding. [source] Bone Response to Implant-Supported Frameworks with Differing Degrees of Misfit Preload: In Vivo Study in RabbitsCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2000Torsten Jemt DDS ABSTRACT Purpose: To study the bone response around implants placed in tibia of rabbits that supported misfitting superstructures secured with different degrees of preload. Materials and Methods: Twelve rabbits were provided with two terminal 10-mm and one intermediate 7-mm-long implant in each tibia. After an integration time of about 9 weeks, nine of the animals received one control framework each (n = 9), designed with good fit to all three implants. In the other tibia of these animals, and in both tibias in the remaining three rabbits, test frameworks (n = 15) were connected with a vertical misfit of about 1 mm to the intermediate implant. The intermediate set screws were tightened with a torque ranging from 15 Ncm to 26 Ncm in the different test frameworks. The fascia and skin was then sutured back over the implants. After a loading period of 2 to 3 weeks, the animals were sacrificed, and histomorphometric measurements were made and correlated to the different levels of preload of the central implant. Results: The mean bone-to-metal contact for the three best consecutive threads of the central implant was 40% for both test and control sites (p > .05). Compared to the other regions of the implant thread, less bone-to-metal contact was found at the tip of the test implant threads in the low preload group (p < .05). However, the same relation was not observed in the high preload group. A significant correlation was observed between increasing degree of preload in the central screw joint and increasing bone-to-metal contact, most obviously noticed at the tip of the implant thread (p < .01). Conclusions: Misfit stress levels of clinical magnitudes do not seem to jeopardize osseointegration per se. On the contrary, clinical levels of preload stress seem to significantly promote bone remodeling at the tip of the implant thread. [source] Supple Praxis: A Paralogical Strategy for ProblemsCOMMUNICATION THEORY, Issue 3 2010Dan H. DeGooyer Jr. Based on Lyotard's (1984) paralogy, I provide a paralogical approach to problems in which participants identify and describe grammars of problems as a means to engage them. I provide paralogical grammars of extant problems and their solutions (i.e., performative, reliable, accidental, and wicked) to articulate how they move from more to less easily solved, with an increasing degree of complexity and stake. I offer paralogical action steps to enact a supple praxis as demonstrated through a discussion of hellish problems, a fifth problem type. Participants paralogically address incommensurability as they solve their current problem, so that they may face their next incommensurable problem. Practitioners using a paralogical approach thus both adeptly solve current problems and prepare for unknown future problems. La praxis souple : une stratégie paralogique face aux problèmes Dan H. DeGooyer, Jr. À partir de la paralogie de Lyotard (1984), je développe une approche paralogique pour affronter les problèmes, approche par laquelle les participants identifient et décrivent des grammaires de problèmes comme moyen d'y faire face. J'offre des grammaires paralogiques de problèmes existants (performatifs, fiables, accidentels et pernicieux) et leurs solutions, afin d'exprimer clairement les manières dont ces problèmes sont de plus en plus difficiles à résoudre, alors que leur degré de complexité et d'importance augmente. Je présente des étapes d'action paralogique afin de mettre en actes une praxis souple, telle que démontrée dans une discussion des problèmes infernaux, un cinquième type de problèmes. Les participants traitent de manière paralogique de l'incommensurabilité quand ils résolvent leur problème actuel, de manière à ce qu'ils affrontent le problème incommensurable suivant. Ainsi, les intervenants qui utilisent une approche paralogique résolvent de façon experte leurs problèmes actuels et se préparent également pour les problèmes futurs qui leur sont encore inconnus. Weiche Praxis: Eine paralogische Strategie für Probleme Dan H. DeGooyer, Jr. Basierend auf der Paralogie von Lyotard (1984) diskutiere ich einen paralogischen Ansatz für Probleme, die Teilnehmer erkennen und deren Grammatik sie beschreiben als ein Mittel, mit diesen Problemen umzugehen. Ich bestimme die paralogische Grammatiken von bestehenden Problemen und ihren Lösungen (z.B. performative, reliable, unbeabsichtigte und boshafte) um auszudrücken, wie sie diese im Feld zwischen mehr oder weniger leicht zu lösen und einem zunehmenden Grad an Komplexität und Einsatz bewegen. Ich biete paralogische Handlungsschritte, um Möglichkeiten einer weichen Praxis darzustellen, wie sie in der Diskussion um infernale Probleme, einem Typ 5-Problem, vorkommen. Die Teilnehmer befassen sich paralogisch mit der Unmessbarkeit während sie ihre aktuellen Probleme lösen, so dass sie ihr nächstes unmessbares Problem angehen können. Praktiker, die einen paralogischen Ansatz verfolgen, lösen also aktuelle Probleme und bereiten sich für unbekannte Probleme in der Zukunft vor. La Práctica Flexible: Una Estrategia Para-lógica para los Problemas Dan H. DeGooyer, Jr. Emmanuel College, University of Iowa, 312 Administrative Building, Boston, MA O2115, USA Resumen Basado en la para-logia de Lyotard (1984), proveo de una aproximación para-lógica a los problemas en la cual los participantes se identifican y describen las gramáticas de los problemas como un medio para comprometerse con ellos. Proveo de una gramática para-lógica de problemas existentes y sus soluciones (a saber, de performancia creíble, accidental, y malintencionado) que articula cómo ellos mueven de más a menos fácilmente solucionados, con un incremento en el grado de complejidad e interés. Ofrezco los pasos de la acción para-lógica una práctica flexible demostrada a través de una discusión de problemas infernales, un quinto tipo de problema. Los participantes trataron para-lógicamente la inconmensurabilidad al resolver el problema corriente, de manera tal que puedan enfrentar el problema inconmensurable siguiente. Los practicantes usando el enfoque para-lógico resolvieron así en forma experta los problemas y se prepararon para los problemas futuros inciertos. [source] Histopathologic grading of medulloblastomasCANCER, Issue 2 2002A Pediatric Oncology Group Study Abstract BACKGROUND Medulloblastomas are small cell embryonal tumors of the cerebellum found predominantly in children, only slightly more than half of whom survive. Predicting favorable outcome has been difficult, and improved stratification clearly is required to avoid both undertreatment and overtreatment. Patients currently are staged clinically, but no pathologic staging system is in use. Two rare subtypes at extreme ends of the histologic spectrum, i.e., medulloblastomas with extensive nodularity and large cell/anaplastic medulloblastomas, are associated with better and worse clinical outcomes, respectively. However, there is little data about correlations between histologic features and clinical outcome for most patients with medulloblastomas that fall between these histologic extremes of nodularity and anaplasia. Therefore, the authors evaluated the clinical effects of increasing anaplasia and nodularity in a large group of children with medulloblastomas, hypothesizing that increasing nodularity would predict better clinical outcomes and that increasing anaplasia would presage less favorable results. METHODS Medulloblastomas from 330 Pediatric Oncology Group patients were evaluated histologically with respect to extent of nodularity, presence of desmoplasia, grade of anaplasia, and extent of anaplasia. Pathologic and clinical data were then compared using Kaplan,Meier and log-rank analyses. RESULTS Increasing grade of anaplasia and extent of anaplasia were associated strongly with progressively worse clinical outcomes (P < 0.0001 for both). Significant anaplasia (moderate or severe) was identified in 24% of medulloblastoma specimens. Neither increasing degrees of nodularity nor desmoplasia were associated significantly with longer survival. CONCLUSIONS Moderate anaplasia and severe anaplasia were associated with aggressive clinical behavior in patients with medulloblastomas and were detected in a significant number of specimens (24%). Pathologic grading of medulloblastomas with respect to anaplasia may be of clinical utility. Cancer 2002;94:552,60. © 2002 American Cancer Society. [source] | ||||||||||||||||||||||