bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Celecoxib on Emotional Stress and Pain-Related Behaviors Evoked by Experimental Tooth Movement in the Rat
Authors: Shibazaki Tatsunori , Yozgatian Joseph H. , Zeredo Jorge L. , Gonzales Carmen , Hotokezaka Hitoshi , Koga Yoshiyuki , Yoshida Noriaki
Published: May 2009

Objective: To test the efficacy of an animal model of pain and stress and evaluate the effects of celecoxib administered when orthodontic force is applied.

Materials and Methods: A 20-g reciprocal force was applied via an orthodontic appliance to the maxillary left first and second molars of 7-week-old male Sprague-Dawley rats. Rat behavior was evaluated at 5, 24, and 48 hours after the appliance was set. Behavior was assessed in a test field by the number of lines crossed in the first 30 seconds and 5 minutes following force application; number of lines crossed to the center; rearing time; and facial grooming time. Experimental group 1 received intraperitoneal administration of 30 mg/kg celecoxib before every behavioral test. Experimental group 2 received 90 mg/kg before the first behavioral test, and physiologic saline was administered before the remaining behavioral tests. Control groups received saline before every behavioral test and were given passive (passive control group) and active (active control group) appliances, respectively.

Results: Parameters related to pain increased in the active controls, whereas the parameters in the experimental groups decreased to the level seen in the passive controls. Statistically significant differences in pain-related behavior between control and experimental groups were found at 5 and 24 hours after placing the appliance. Stress-related behavior was significantly less in the experimental groups compared to the active control group during experimental periods.

Conclusions: The administration of celecoxib relieves pain- and stress-related behavior evoked by orthodontic tooth movement in the rat. This model might be a useful tool for the evaluation of pain and stress.
Chronology of Islet Differentiation Revealed By Temporal Cell Labeling
Authors: Miyatsuka Takeshi , Li Zhongmei , German Michael S.
Published: May 2009

OBJECTIVE

Neurogenin 3 plays a pivotal role in pancreatic endocrine differentiation. Whereas mouse models expressing reporters such as eGFP or LacZ under the control of the Neurog3 gene enable us to label cells in the pancreatic endocrine lineage, the long half-life of most reporter proteins makes it difficult to distinguish cells actively expressing neurogenin 3 from differentiated cells that have stopped transcribing the gene.

RESEARCH DESIGN AND METHODS

In order to separate the transient neurogenin 3 –expressing endocrine progenitor cells from the differentiating endocrine cells, we developed a mouse model (Ngn3-Timer) in which DsRed-E5, a fluorescent protein that shifts its emission spectrum from green to red over time, was expressed transgenically from the NEUROG3 locus.

RESULTS

In the Ngn3-Timer embryos, green-dominant cells could be readily detected by microscopy or flow cytometry and distinguished from green/red double-positive cells. When fluorescent cells were sorted into three different populations by a fluorescence-activated cell sorter, placed in culture, and then reanalyzed by flow cytometry, green-dominant cells converted to green/red double-positive cells within 6 h. The sorted cell populations were then used to determine the temporal patterns of expression for 145 transcriptional regulators in the developing pancreas.

CONCLUSIONS

The precise temporal resolution of this model defines the narrow window of neurogenin 3 expression in islet progenitor cells and permits sequential analyses of sorted cells as well as the testing of gene regulatory models for the differentiation of pancreatic islet cells.
Dynamometer Measurements of Grip and Knee Extension Strength: Are They Indicative of Overall Limb and Trunk Muscle Strength?
Authors: Bohannon Richard W.
Published: May 2009

Single dynamometric measures are sometimes used to characterize overall muscle strength. This study examined the legitimacy of that practice by assessing how dynamometer measures of grip and knee extension strength related to manual muscle-test grades of each upper and lower limb and of the trunk. Based on correlations and principal component analysis, grip dynamometry can be used to characterize upper limb strength but not lower limb strength; knee extension dynamometry can be used to characterize lower limb and trunk strength.
Evaluating Construct Validity of the Slosson Visual-Motor Performance Test Using the Rasch Measurement Model
Authors: Brown Ted , Unsworth Carolyn
Published: May 2009

The aim of this study was to evaluate the construct validity of the Slosson Visual-Motor Performance Test by applying the Rasch Measurement Model to evaluate the test's scalability, dimensionality, differential item functioning based on sex, and hierarchical ordering. Participants were 400 children ages 5 to 12 years, recruited from six schools in Melbourne, Victoria, Australia. The Slosson Visual-Motor Performance Test requires a child to copy 14 different geometric designs three times each for a total 42 scale items. Children completed the test under the supervision of an occupational therapist. Overall, 13 of 42 of the test items exhibited poor measurement properties. As nearly one-third of the scale items were problematic, the Slosson Visual-Motor Performance Test in its current form is not recommended for clinical use.
Goal Priming and Self-Efficacy: Independent Contributions to Motor Performance
Authors: Légal Jean-Baptiste , Meyer Thierry
Published: May 2009

It is well-established that goal pursuit and performance are responsive to the goal characteristics (e.g., difficulty, specificity) and beliefs about self and the task (e.g., self-efficacy). Also, contextual factors may lead to nonconscious goal activation and pursuit. Nevertheless, much remains to be discoverd concerning the way conscious and nonconscious goals are related. In this study, the way in which self-efficacy and nonconscious goal priming may affect a goal-directed activity was explored. 67 right-handed participants with high or low self-efficacy on their motor skills performed a drawing task associated with an accuracy instruction. Before task performance, they were primed with accuracy-related words (goal-compatible condition), inaccuracy-related words (goal-incompatible condition), or received no priming manipulation (control condition). Analysis indicated that performance of the motor task was independently influenced by self-efficacy and goal priming.
Resampling Permutation Probability Values for Cronbach's Alpha
Authors: Prelog Andrew J. , Berry Kenneth J. , Mielke Paul W.
Published: May 2009

A permutation procedure to compute a resampling probability value and empirical quantile limits is provided for Cronbach's alpha measure of internal reliability. The underlying assumptions for the conventional use of alpha are discussed. The use of a permutation test for Cronbach's alpha is highlighted as a valuable tool when sample sizes are small and necessary assumptions cannot be met.
Learning and Context of Use for Small-Screen Leading Displays on Visual Performance in a Chinese Sample
Authors: Chien Yu-Hung
Published: May 2009

Leading displays represent mechanisms for exhibiting temporal instead of spatial information to overcome the limited display space of mobile devices. Prior studies focused only on information presented but disregarded the influence of context of use and learnability. In this study, 12 Chinese-speaking college students were presented a small-screen mobile device that simultaneously showed 100 Chinese characters and a 30-character leading display. Analyzed were presentation rate (250, 350, and 450 characters per minute), presentation mode (character-by-character or word-by-word), and learning (5 practice sessions) by instructing the subjects to perform a static information search task to identify the location of target characters on the screen and through an evaluation of reading comprehension for the text presented in the leading display. There was no significant change in performance over the 5 days of practice, but the rate of presentation and word-by-word presentation significantly affected reading comprehension. Results indicated that none of the leading-display factors distracted subjects from the static information-search task, but they were influenced by comprehension of the leading-display content.
Influence of Attention to Somatic Information on Emotional and Autonomic Responses
Authors: Murakami Hiroki , Ohira Hideki , Matsunaga Masahiro , Kimura Kenta
Published: May 2009

The present study aimed to investigate the dissociable effects of two forms of self-focus on emotional and autonomic responses. One form is suppression, which includes the suppression of heart rate and self-evaluation of performance. The other is observation, which includes attention to one's own heart rate with no suppression and no evaluation. 26 undergraduate and graduate students from the Nagoya University campus (13 men, 13 women), ages 18 to 24 years ( M = 20.7, SD = 1.6) were recruited. Participants were provided with their own heart rate as feedback for 5 min., during which participants conducted a self-focus manipulation. Several days after the experimental session for one condition, the same participants conducted another experimental session for the other condition. Instruction to suppress enhanced physiological arousal and subsequent negative emotions; however, instruction to observe did not increase physiological arousal or negative emotions.
Interaction of Hand Preference with Eye Dominance on Accuracy in Archery
Authors: Laborde Sylvain , Dosseville Fabrice E. M. , Leconte Pascale , Margas Nicolas
Published: May 2009

In this study, the interaction of hand preference, eye dominance, and performance in archery was investigated. Beginners' accuracy (right-handed French students (48 men, 34 women) from the University of Sport Sciences ( M age = 19.3 yr., SD = 1.7 yr.), were tested and 1,323 practitioners were given a laterality questionnaire. Analysis suggested the interaction of hand preference and eye dominance might influence accuracy of the novice archers (uncrossed patterns were more accurate) when the bow was used without sights, but the use of sights by practitioners seemed to eliminate this effect.
Selection of Resistance Exercise Intensity Using Ratings of Perceived Exertion from the OMNI—RES
Authors: Lagally Kristen M. , Amorose Anthony J. , Rock Brandi
Published: May 2009

This investigation evaluated the use of OMNI–Resistance Exercise Scale ratings of perceived exertion as a method for selecting training intensities that are appropriate for improving muscular fitness. 20 women ( M = 21.3 yr., SD = 2.2) completed a one-repetition maximum for the chest press and knee extension. Participants returned for three sessions during which they were asked to select resistances which elicited the feelings of exertion associated with ratings of 3 (i.e., Easy to Somewhat easy), 6 (i.e., Somewhat hard) and 9 (i.e., Hard to Extremely hard). The average percentage of maximum lifted at a 3, 6, and 9 was 50, 69, and 88% for the chest press and 56, 74, and 90% for the knee extension, respectively. Effect sizes indicated large differences across the three ratings of perceived exertion within sessions and small differences between sessions. Intraclass correlation coefficients ranged from .69 to .95. The results indicated that OMNI–Resistance Exercise Scale ratings of 3, 6, and 9 can be used to accurately and reliably select intensities that are appropriate for improving muscular fitness.
Music and Light during Indoor Cycling
Authors: Shaulov Naama , Lufi Dubi
Published: May 2009

The present research is a field study assessing effects of music and light on physical performance and subjective feelings of 28 participants (14 men, 14 women) in fitness classes using indoor cycling. Participants performed four sessions under different conditions of music and light. Analysis showed a sense of pleasure was significantly higher when music was introduced during the exercise. A significant interaction of music and light indicated that participants experienced less sense of tiredness when they trained with music and lights were dimmed. Light alone had no effect on any of the subjective measures. Physiological measurements showed that light and music did not influence amount of energy exerted (heart rate) or energy expended (calories). Apparently, participants do not work harder when music is present; however, they report more pleasure and less tiredness while exercising with music and dimmed light. It is recommended that music and dimmed light might be used during such activities to heighten pleasure and reduce tiredness while emphasizing fitness achieved.
Is Manipulation of Color Effective in Study of the Global Precedence Effect?
Authors: Vidal-López Joaquín , Romera-Vivancos Juan Antonio
Published: May 2009

This article evaluates the use of color manipulation in studying the effect of global precedence and the possible involvement of the magnocellular processing system. The analysis shows variations of color used in three studies produced changes on the global precedence effect, but findings based on this technique present some methodological problems and have little theoretical support from the magnocellular processing-system perspective. For this reason, more research is required to develop knowledge about the origin of these variations in global precedence.
Diversity and distribution of idioblasts producing calcium oxalate crystals in Dieffenbachia seguine (Araceae)
Authors: Coté Gary G.
Published: May 2009

Although cells that synthesize crystals are known throughout the plant kingdom, their functional significance is still unknown. Mechanical support, mineral balance, waste sequestration, and protection against herbivores have all been proposed as crystal functions. To seek clues to their role(s), I systematically examined all organs except fruit of Dieffenbachia seguine (Araceae) for crystals. Crystals were found in nearly every organ. Raphides (long, slim, pointed crystals) were most common, but druses (crystal aggregates) and prisms were also found. Raphides varied in size by a factor of 10 and also in organization from tightly bundled to loosely organized. Biforines, a type of cell capable of expelling raphides, or biforine‐like cells, were found in nearly all organs, but especially in leaves, spathes, and anthers. Different organs had different crystal complements, and characteristic crystals were found at specific locations, such as among pollen, along the undersides of leaf veins, and at root branch points. All crystals appeared to be composed of calcium oxalate, based on acid solubility. Possible roles of the crystals are discussed in light of these findings.
Employee health and wellness in South Africa: The role of legislation and management standards
Authors: Sieberhagen Charlotte , Rothmann Sebastiaan , Pienaar Jacobus
Published: May 2009

The aim of this study was to investigate the role that legislation and management standards might play in ensuring occupational health and wellness in South Africa. The Occupational Health and Safety Act of 1993 determines that an employer must establish and maintain a work environment that is safe and without risk to the health of employees. It seems that there is a lack of guidance in the laws and statutes with regard to dealing with employee health and wellness. A management standards approach, which involves all the role players in the regulation of employee health and wellness, should be implemented.
A steady‐state and time‐resolved fluorescence, circular dichroism study on the binding of myricetin to bovine serum albumin
Authors: Tian Jianniao , Zhao Yanchun , Liu Xiuhong , Zhao Shulin
Published: May 2009

The binding mechanism of myricetin (Myr) to bovine serum albumin was investigated by using steady‐state and time‐resolved fluorescence and circular dichroism. The results of the steady‐state fluorescence quenching experiment indicate that it is a static quenching process (CMyr/CBSA ≤ 3) at low quencher concentration and the binding site is located near the Trp212 residue. The association constants at the different temperatures were calculated. From the thermodynamic parameters, enthalpy change (ΔH0), Gibbs free energy change (ΔG0) and entropy change (ΔS0) obtained in the experiment, it was found that hydrophobic and electrostatic interactions play important roles in binding Myr to BSA. According to the Föster energy transfer theory, the separation distance, r, the energy transfer efficiency, E, and Föster radius, R0, were calculated. The results obtained from the above experiments indicate that Myr can be tightly bound to BSA. Then, the effects of ionic strength, metal ion, pH and surfactants on the binding Myr and BSA were investigated, which also showed that electrostatic and hydrophobic interactions play a major role in the association process. On the other hand, the conformation and secondary structure of BSA were further studied through circular dichroism and fluorescence synchronous spectra. It was found that the conformation and secondary structure of BSA had also changed after interaction with Myr. The time‐resolved fluorescence study showed that the short lifetime of BSA decreased after the addition of Myr, which implies that the buried Trp 212 is the main binding site. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of CdSe quantum dots with luminescence in the violet region of the solar spectrum
Authors: Shukla Nisha , Nigra Michael M.
Published: May 2009

We have designed a simple, one‐step synthesis of CdSe quantum dots with photoluminescence frequencies ranging from the red through to the violet region of the solar spectrum. The photoluminescence peaks have FWHM of 30 nm indicating absorption over a narrow range of wavelengths. The effect of solvent type and solvent boiling point on the physical and photoluminescence properties of the quantum dots has been studied. High boiling point, non‐polar solvents shift the photoluminescence peak to longer wavelengths and low boiling point, polar solvents shift the photoluminescence peak to shorter wavelengths. Copyright © 2009 John Wiley & Sons, Ltd.
Plant wide simulation using the free chemical process simulator Sim42: Natural gas separation and reforming
Authors: Dias Rafael Silva , Silva Leandro Cardoso , de Assis Adilson Jose
Published: May 2009

This article addresses the use of Sim42, a steady‐state free process simulator, as a powerful tool to teach heat integration and parametric optimization in a complete plant. It was considered a natural gas plant as a case study. The thermodynamic package used in the simulations was validated using experimental data published in the literature. The results were compared with the commercial simulator HYSYS and plant information. Good agreement was achieved. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 476–484, 2010; View this article online at wileyonlinelibrary.com; DOI 10.1002/cae.20200
Measuring therapeutic alliance between oncologists and patients with advanced cancer
Authors: Mack Jennifer W. , Block Susan D. , Nilsson Matthew , Wright Alexi , Trice Elizabeth , Friedlander Robert , Paulk Elizabeth , Prigerson Holly G.
Published: May 2009

BACKGROUND:

Patients consider their human connection with a physician an important aspect of end‐of‐life (EOL) care. In this study, the authors sought to develop and validate a measure of therapeutic alliance between patients with advanced cancer and their physicians and to evaluate the effects of therapeutic alliance on EOL experiences and care.

METHODS:

The Human Connection (THC) scale was developed to measure the extent to which patients felt a sense of mutual understanding, caring, and trust with their physicians. The scale was administered to 217 patients with advanced cancer along with measures of attributes that have been related hypothetically to therapeutic alliance, including emotional acceptance of terminal illness. EOL outcomes in 90 patients who died during the study also were examined.

RESULTS:

The 16‐item THC questionnaire was consistent internally (Cronbach α = .90) and valid based on its expected positive association with emotional acceptance of terminal illness (r = .31; P < .0001). THC scores were related inversely to symptom burden (r = −.19; P = .006), functional status (Karnofsky performance status; r = .22; P = .001), and mental illness (THC score: 50.69 for patients with any Diagnostic and Statistical Manual [DSM] diagnosis vs 55.22 for patients with no DSM diagnosis; P = .03). THC scores were not associated significantly with EOL discussions (P = .68). Among the patients who died, EOL intensive care unit (ICU) care was associated inversely with therapeutic alliance (THC score: 46.5 for patients who received ICU care vs 55.5 for patients without ICU care; P = .002), so that patients with higher THC scores were less likely to spend time in the ICU during the last week of life.

CONCLUSIONS:

The THC scale is a valid and reliable measure of therapeutic alliance between patients with advanced cancer and their physicians. In addition, there was no evidence to suggest that EOL discussions harm patients' therapeutic alliance. A strong therapeutic alliance was associated with emotional acceptance of a terminal illness and with decreased ICU care at the EOL among patients with advanced cancer. Cancer 2009. © 2009 American Cancer Society.
Twenty years of controversy surrounding combined androgen blockade for advanced prostate cancer
Authors: Moul Judd W.
Published: May 2009

The current issue of Cancer includes a report on a concise, randomized controlled trial (RCT) with long‐term follow‐up that favors combined androgen blockade with bicalutamide versus lutenizing hormone‐releasing hormone monotherapy in Japanese men with locally advanced and metastatic prostate cancer. It has been 20 years since the first RCT on CAB was published, and the debate continues.
Racial/ethnic diversity in children's oncology clinical trials
Authors: Lund Mary Jo , Eliason Mark T. , Haight Ann E. , Ward Kevin C. , Young John L. , Pentz Rebecca D.
Published: May 2009

BACKGROUND.

During the past 50 years, clinical trials have led to dramatic improvement in pediatric cancer survival. Prior studies have shown that racial/ethnic and age groups have not been enrolled proportionally. Whites, Hispanics, and adolescents are under‐represented and black children are over‐represented. This study identifies the current racial/ethnic/age/sex representation in pediatric (ages birth to 19 years) cancer treatment trials.

METHODS.

The authors compared the observed proportions (O) of US children enrolled in Children's Oncology Group (COG) clinical trials from 2000 through 2003 with expected proportions (E), based on Surveillance, Epidemiology, and End Results (SEER) data. The enrollees were subgrouped by race/ethnicity, age, sex, and cancer type (solid or lymphohematopoietic). Chi‐square tests and 95% confidence intervals were used for O versus E comparisons.

RESULTS.

Although representation was fairly proportional for each racial/ethnic group, significantly under‐represented solid tumor subgroups were whites (males particularly), adolescents ages 10 to 19 years, and Hispanics aged <10 years. For lymphohematopoietic cancers, significantly under‐represented subgroups were blacks, Hispanics, adolescents ages 10 to 19 years, blacks aged <10 years, Hispanics aged <5 years, white and black males, and black and Hispanic females. The most significantly under‐represented groups were adolescents ages 15 to 19 years for both solid (9.1% O vs 34.3% E) and lymphohematopoietic (11.0% O vs 30.2% E) cancers and Hispanic females with lymphohematopoietic cancers (11.9% O vs 20.5% E). COG enrolled 26.8% of expected cancer cases.

CONCLUSIONS.

Although racial/ethnic groups are proportionally represented in COG trials, some specific subgroups including the youngest black and Hispanic children, Hispanic females, and particularly white adolescents ages 15 to 19 years may be under‐represented and may benefit from targeted attention. Cancer 2009. © 2009 American Cancer Society.
DNA repair polymorphisms associated with cytogenetic subgroups in B‐cell chronic lymphocytic leukemia
Authors: Ganster Christina , Neesen Jürgen , Zehetmayer Sonja , Jäger Ulrich , Esterbauer Harald , Mannhalter Christine , Kluge Britta , Fonatsch Christa
Published: May 2009

Genetic polymorphisms in DNA repair genes can affect the risk of developing different forms of cancer. Therefore, we have studied the putative association of seven single nucleotide polymorphisms (SNPs) in five DNA repair genes with the incidence of chronic lymphocytic leukemia (CLL). We included 461 CLL patients and the same number of age‐ and sex‐matched controls. As chromosomal aberrations are important prognostic markers in CLL, we additionally correlated the SNPs with the occurrence of favorable and unfavorable cytogenetic aberrations in CLL patients. Patients with del(13q) as a sole aberration were allocated to the favorable cytogenetic risk group, and patients with del(17p) and/or del(11q) to the unfavorable cytogenetic risk group. All investigated SNPs were equally distributed between patients with the favorable cytogenetic aberration and controls. However, differences were observed in the distribution of rs13181 in ERCC2 between all CLL patients and controls. Moreover, the clearest differences were found for rs13181 in ERCC2 and rs25487 in XRCC1 between CLL patients with unfavorable cytogenetic aberrations and controls. These data suggest that inborn genetic polymorphisms may predict the outcome of CLL. © 2009 Wiley‐Liss, Inc.
Correlating percutaneous absorption with physicochemical parameters in vivo in man: agricultural, steroid, and other organic compounds
Authors: Alikhan Ali , Farahmand Sara , Maibach Howard I.
Published: May 2009

In vitro data are currently used to predict cutaneous chemical exposure based on physicochemical parameters. However, this in vitro data may not sufficiently account for what occurs in vivo. Previously, we modeled (via multivariate analysis) percutaneous absorption with physicochemical parameters using in vivo human transdermal patch‐based data. In our current study, we correlated absorption data from three human in vivo data sets to physicochemical parameters. Most univariate and multivariate analyses did not provide satisfactory fits, and only steroids demonstrated significant relationships, where: (1) total percentge absorption inversely correlated with molecular weight and number of hydrogen bond acceptor groups on the molecule; and (2) maximal absorption rate inversely correlated with molecular weight, and number of hydrogen bond donor and acceptor groups on the molecule. For the most part, however, disparities exist between our previous results with transdermal patches and our current results with acetone as the solvent. Reasons for this discordance may include: drug–vehicle interactions, compound variability and endpoint differences. With such variability between in vivo human data, current in vitro predictive models should be critically scrutinized. Copyright © 2009 John Wiley & Sons, Ltd.
Evaluation of the effect of the degree of acetylation on the inflammatory response to 3D porous chitosan scaffolds
Authors: Barbosa Judite N. , Amaral Isabel F. , Águas Artur P. , Barbosa Mário A.
Published: May 2009

The effect of the degree of acetylation (DA) of 3D chitosan (Ch) scaffolds on the inflammatory reaction was investigated. Chitosan porous scaffolds with DAs of 4 and 15% were implanted using a subcutaneous air‐pouch model of inflammation. The initial acute inflammatory response was evaluated 24 and 48 h after implantation. To characterize the initial response, the recruitment and adhesion of inflammatory cells to the implant site was studied. The fibrous capsule formation and the infiltration of inflammatory cells within the scaffolds were evaluated for longer implantation times (2 and 4 weeks). Chitosan with DA 15% attracted the highest number of leukocytes to the implant site. High numbers of adherent inflammatory cells were also observed in this material. For longer implantation periods Ch scaffolds with a DA of 15% induced the formation of a thick fibrous capsule and a high infiltration of inflammatory cells within the scaffold. Our results indicate that the biological response to implanted Ch scaffolds was influenced by the DA. Chitosan with a DA of 15% induce a more intense inflammatory response when compared with DA 4% Ch. Because inflammation and healing are interrelated, this result may provide clues for the relative importance of acetyl and amine functional groups in tissue repair and regeneration. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Mechano‐functional assessment of human mesenchymal stem cells grown in three‐dimensional hyaluronan‐based scaffolds for cartilage tissue engineering
Authors: Stok Kathryn S. , Lisignoli Gina , Cristino Sandra , Facchini Andrea , Müller Ralph
Published: May 2009

Human mesenchymal stem cells (hMSCs) are an alternative cell source in bioconstruct production for cartilage regeneration, and hyaluronic acid (HA) is a widely‐used bioabsorbable scaffold material used for cartilage regeneration. In this work, the aims were to evaluate the mechanical competency of hMSC‐seeded HA scaffolds compared with native intact human articular cartilage, and in relation to its cellular properties. Human MSCs were grown under static conditions in HA scaffolds and then tested, in stepwise, stress‐relaxation indentation, 7, 14, and 21 days later. Scaffolds at days 14 and 21 showed a significant increase in mechanical measures when compared with day 7 and unseeded scaffold material, but did not achieve the same levels as human cartilage. There was consistent stiffness within the scaffold, with a decreased stiffness around the edge. In vitro culture of hMSC‐seeded HA scaffolds over 3 weeks produces a white, solid tissue compared with unseeded constructs. Increased cell proliferation and collagen type II expression were also seen over this period of time. These results demonstrate the competency of the neo‐formed cartilage‐like tissue in relation to its mechanical and cellular properties, and further, the importance, for future clinical use, of implanting this construct after 14 days of culture. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
VEGF‐E enhances endothelialization and inhibits thrombus formation on polymeric surfaces
Authors: Knetsch Menno L. W. , Koole Leo H.
Published: May 2009

Thrombotic complications of long‐term blood‐contacting devices can be avoided by formation of an endothelial cell layer on the blood‐contacting surface. The endothelial cells form a bioactive boundary between the synthetic surface and blood, regulating haemostasis and inflammation. Biofunctionalization of synthetic blood‐contacting surfaces is necessary to accommodate growth of endothelial cells. Vascular endothelial growth factor E (VEGF‐E) or collagen I may stimulate endothelialization of a polymeric surface coating of a prototype small diameter vascular prosthesis. VEGF‐E was produced in Escherichia coli and could be easily purified in large quantities. Recombinant VEGF‐E or purified collagen I was allowed to adsorb onto the polymeric surfaces and enhanced formation of an endothelial cell layer. Adsorption of VEGF‐E was increased by the inclusion of the anti‐coagulant drug heparin in the polymeric coating. Collagen I adsorption induced rapid thrombin generation and increased platelet adhesion on surfaces with or without heparin. VEGF‐E inhibited thrombus formation, and did not interfere with the anti‐thrombogenic effect of heparin. Additionally, VEGF‐E did not affect platelet adhesion. Adsorption of VEGF‐E, especially on heparin containing surfaces, provides an economical strategy to improve endothelialization of cardiovascular implants without disturbing blood‐compatibility. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Substrate influence on cell shape and cell mechanics: HepG2 cells spread on positively charged surfaces
Authors: Saravia Veronica , Toca‐Herrera José L.
Published: May 2009

A human hepatoma cell line (HepG2) was cultured on positively and negatively charged polyelectrolytes. Cell/surface adhesion and cell shape evolution were followed with quartz microbalance with dissipation (QCM‐D) and optical microscopy as a function of time, respectively. In particular, substrates coated with poly(ethyleneimine) (PEI) led to fast cell attachment and further spreading, with average maximum frequency Δf = 79 Hz and dissipation ΔD = 40 × 10−6. On the contrary, no cell spreading was observed on poly(sodium‐4‐styrenesulfonate) (PSS), with Δf = 33 Hz and ΔD = 4.5 × 10−6. Atomic force microscopy (AFM) was used to investigate the influence of cell shape on its mechanical properties. Considering the cells as an homogenous solid material, the corresponding elastic modulus was estimated using the Hertz model. The elastic modulus was calculated at the central part of the cell, and the average values obtained were 191 ± 14 Pa and 941 ± 58 Pa for cells adsorbed on PSS and PEI, respectively. Thus, different cell–substrate interaction implied different cell mechanical properties reflected in a higher elastic modulus for stronger cell/substrate interaction. The combination of QCM‐D, AFM, and optical microscopy allowed the online study of the cell adhesion process, and the mechanical properties of the adhered cells. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
Fabrication of composite polyaniline/CNT nanofibers using an ultrasonically assisted dynamic inverse emulsion polymerization technique
Authors: Zelikman E. , Suckeveriene R. Y. , Mechrez G. , Narkis M.
Published: May 2009

This communication describes an ultrasonically assisted in‐situ dynamic inverse emulsion polymerization process of aniline in the presence of multi‐walled carbon nanotubes (MWNT) in toluene. During polymerization, MWNT are coated with polyaniline (PANI), forming a core‐shell structure of nano‐wires observed by high‐resolution scanning electron microscopy (HRSEM). The PANI coating of MWNT leads to a remarkable improvement in separation and dispersion of MWNT in toluene, which otherwise would have rapidly coagulated and settled. The presented dynamic polymerization process is very fast and produces stable clear dispersions. CNT enhances both the mechanical properties and electrical conductivity of PANI. Copyright © 2009 John Wiley & Sons, Ltd.
Piperacillin/tazobactam versus cefepime for the empirical treatment of pediatric cancer patients with neutropenia and fever: A randomized and open‐label study
Authors: Uygun Vedat , Karasu Gulsun Tezcan , Ogunc Dilara , Yesilipek Akif , Hazar Volkan
Published: May 2009

Objectives

This is a prospective, randomized, and open‐label clinical trial that examines the efficiency and safety of PIP/TAZO monotherapy in comparison to cefepime (CEF), for the empirical treatment of pediatric cancer patients with neutropenia and fever.

Methods

One hundred thirty‐one consecutive febrile episodes in 70 neutropenic pediatric cancer patients received randomized treatment either with piperacillin/tazobactam (PIP/TAZO) 80 mg/kg piperacillin/10 mg/kg tazobactam every 6 hr or CEF 50 mg/kg every 8 hr. Clinical response was determined at completion of therapy. Duration of fever, neutropenia, hospitalization, the need for modification of the therapy, and mortality rates were compared between the two groups.

Results

One hundred twenty‐seven episodes in 69 patients (35 females, 34 males) with a median age of 4.2 years were assessed for efficiency (65 PIP/TAZO, 62 CEF). The frequency of success without modification of treatment was nearly identical for both PIP/TAZO (60.0%) and CEF (61.3%) (P > 0.05). The overall response rate, with or without modification of assigned treatment, was 96.9% for PIP/TAZO and 98.4% for CEP (P > 0.05). Infection‐related mortality at the end of the febrile episode was 2.4%. Duration of fever and hospitalization were not different between the treatment groups. No major side effects were observed in neither of the groups.

Conclusions

PIP/TAZO treatment was as effective and safe as CEF monotherapy as an initial empirical regimen in pediatric cancer patients with fever and neutropenia. Pediatr Blood Cancer 2009;53:610–614. © 2009 Wiley‐Liss, Inc.
Oral health and dental anomalies in patients treated for leukemia in childhood and adolescence
Authors: Maciel Júlio César Cordova , de Castro Cláudio Galvão , Brunetto Algemir Lunardi , Di Leone Luciane Pons , da Silveira Heloisa Emília Dias
Published: May 2009

Background

This study was conducted to evaluate oral health and dental anomalies in children treated for acute lymphoblastic leukemia (ALL) and to compare results with those of a group of healthy children matched for sex and age.

Procedure

Fifty‐six children treated for ALL and 56 healthy controls were examined for dental anomalies, and data on decayed, missing, and filled teeth (DMFT) score, visible plaque (VPI), and gingival bleeding (GBI) indices, and saliva flow were collected. Mean age of all children treated for ALL was 5.3 ± 2.6 years at diagnosis and 11.8 ± 4.2 at evaluation. Thirty‐two were males.

Results

Forty‐five treated children (80.4%) had at least one dental anomaly, and patients treated with chemotherapy, radiotherapy, and bone marrow transplantation had the greatest mean number of dental anomalies (15.37 ± 15.03). Patients younger than 5 years at beginning of treatment were also more affected (P = 0.031). Children treated for ALL had a DMFT score of 1.9 ± 4.0, GBI of 26.5%, VPI of 72.0%, and mean saliva flow of 0.19 ml/min; healthy children had a DMFT score of 1.52 ± 3.5, GBI of 11.1%, VPI of 53.8%, and mean saliva flow of 0.27 ml/min.

Conclusion

The treatment of ALL causes a significant increase in the number of dental anomalies. Their GBI and VPI were also elevated. Changes in salivary glands during treatment did not affect saliva flow permanently. Follow‐up of these patients by an oral health team is recommended. Pediatr Blood Cancer 2009;53:361–365. © 2009 Wiley‐Liss, Inc.
High molecular weight thermoplastic polyether ester elastomer by reactive extrusion
Authors: Cho Sunghwan , Jang Yunjoo , Kim Dongmin , Lee Taeyoung , Lee Dongho , Lee Youngkwan
Published: May 2009

A reactive branched thermoplastic polyether‐ester elastomer (TPEE) precursor was synthesized by the esterification reaction of dimethyl terephthalate (DMT) with poly(tetramethylene etherglycol) (PTMEG), 1,4‐butadiene, and glycerol as a soft segment, hard segment, and a branching agent, respectively. The high molecular weight TPEE was further synthesized with the prepared branched TPEE precursor, poly(butylene terephthalate) (PBT) and modified methylene diisocyanate (m‐MDI, 0.5–2.0 wt%) by the reactive extrusion method. Their chemical structures were determined by Fourier Transform Infra Red (FTIR) and Proton‐Nuclear Magnetic Resonance (1H NMR). Thermal characteristics and rheological properties of TPEE were measured by Differential Scanning Calorimetry (DSC) and rheometer as a function of m‐MDI content. The intrinsic viscosity (IV) and melt index ratio (MIR) of TPEE increased as the content of m‐MDI increased up to 1.5 wt% and remained constant thereafter. The variation of the MIR was consistent with that of the IV. The storage modulus and viscosity did not vary with the measurement time up to 1.0 wt% of m‐MDI at the first extrusion, which indicates that the m‐MDI reacted fully. However, the viscosity and storage modulus increased with increasing measurement time at m‐MDI contents over 1.5 wt%. POLYM. ENG. SCI., 2009. © 2009 Societyof Plastics Engineers
Oxygen and carbon dioxide transport through high barrier polyester blends
Authors: Hernández‐Rivera M.A. , de la Mora G. García , Likhatchev D. , de la Cruz‐Guerra C. , Díaz L.L. , López‐Castillo N.N. , Cruz‐Gómez M.J.
Published: May 2009

The transport of oxygen and carbon dioxide through a set of random copolymer films based on poly(ethylene terephthalate) (PET) and poly(ethylene 2,6‐naphthalate) (PEN) were explored. Diffusivity and permeability of both gases decreased with increasing PEN content. The oxygen and carbon dioxide diffusion coefficients decreased 74 and 82% from pure PET to pure PEN, respectively. The presence of stiffer PEN moieties had an effect on the glass transition temperature (Tg) of PET/PEN blends and gas barrier. In the complete range of tested blends, the differential scanner calorimeter analysis displayed a single value of thermal glass transition temperature. As the PEN content was increased, the fractional free volume (FFV) and the diffusion coefficients of the blends were decreased. The Doolittle equation provided the best fit for diffusivity and FFV and showed that the gas transport behavior was better understood when it was taken into consideration the cohesive energy of blends. As the PEN content in films was increased, their rigidity and the glass/rubber transition temperature were increased, and their capacity to be penetrated by small molecules like O2 and CO2 was decreased. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Modeling the development of elastic anisotropy as a result of plastic flow for glassy polycarbonate
Authors: Goel A. , Strabala K. , Negahban M. , Turner J.A.
Published: May 2009

The development of anisotropy as a result of plastic deformation below the glass‐transition temperature is investigated and modeled for amorphous polycarbonate. Initially, isotropic polycarbonate was subjected to different extents of plastic flow in compression, and the development of its anisotropic wave speed moduli were studied using ultrasonic wave speed measurements. Longitudinal and shear wave speed measurements were performed both in the axial and transverse directions, with respect to the axis of compression. The moduli clearly indicated the development of a transversely elastic response as a result of the uniaxial compression. The measured moduli were used to model the elastic response of polycarbonate using a model for stress that depends both on the elastic and plastic parts of the deformation. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Numerical investigation and experimental validation of the performance of a tubular packed bed reactor for hydrogenation of diene‐based polymers
Authors: Madhuranthakam Chandra Mouli R. , Pan Qinmin , Rempel Garry L.
Published: May 2009

A process which comprised a tubular reactor (that can be packed with different internal structures) has been modeled and theoretically analyzed for conducting the hydrogenation of nitrile butadiene rubber (NBR). The dynamics of the tubular reactor and the intrinsic hydrogenation kinetics are coupled, and detailed numerical simulations are performed under isothermal and isobaric conditions. The proposed model thus obtained involves coupled, nonlinear, partial differential equations (distributed parameter system). The effect of different reactor design parameters such as Peclet number, carbon–carbon double bond loading, mass transfer to reaction resistance, and solubility of hydrogen with respect to hydrogenation of the NBR has been investigated numerically. The conversions predicted using the proposed model for tubular packed bed reactor are compared with those possible in conventional plug flow reactor and continuous stirred tank reactor models. The optimal parameters and operating conditions for efficient production of hydrogenated NBR are suggested. Finally, the validity of the proposed model is confirmed by comparing the predicted and the experimental degree of hydrogenation obtained in a tubular reactor packed with Intalox saddles. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Estimation of the interaction energy between small molecules and a silica model as an approach for predicting the interaction order between elastomers and silica
Authors: Pérez León D , Florez Elizabeth , Mark James E , López Betty L
Published: May 2009

BACKGROUND: Many elastomers are reinforced with fillers to improve their mechanical properties; good reinforcement requires favorable interactions between the elastomeric chains and the surfaces of the filler particles. A useful goal is the development of computational methods that estimate these interactions, and thereby guide choices of fillers for elastomers based on the structures of the two components in nanocomposites in general.

RESULTS: Experimental results available from inverse gas chromatography rank nitriles, aromatics and 1‐alkenes with regard to the magnitude of favorable interactions with silica reinforcing particles. Calculations using the Gaussian 03 package of computer programs were carried out, both with and without corrections for superposition errors. For the nitrile compounds, the formation of hydrogen bonds was predicted, and the interactions of the aromatic and 1‐alkene compounds with silica were shown to be dependent on electron transfer from the silica to the tested molecules.

CONCLUSION: The method developed should be useful for ranking polymer–filler combinations in general with regard to the interactions known to be conducive to good reinforcement. Copyright © 2009 Society of Chemical Industry
Improved prediction of protein side‐chain conformations with SCWRL4
Authors: Krivov Georgii G. , Shapovalov Maxim V. , Dunbrack Roland L.
Published: May 2009

Determination of side‐chain conformations is an important step in protein structure prediction and protein design. Many such methods have been presented, although only a small number are in widespread use. SCWRL is one such method, and the SCWRL3 program (2003) has remained popular because of its speed, accuracy, and ease‐of‐use for the purpose of homology modeling. However, higher accuracy at comparable speed is desirable. This has been achieved in a new program SCWRL4 through: (1) a new backbone‐dependent rotamer library based on kernel density estimates; (2) averaging over samples of conformations about the positions in the rotamer library; (3) a fast anisotropic hydrogen bonding function; (4) a short‐range, soft van der Waals atom–atom interaction potential; (5) fast collision detection using k‐discrete oriented polytopes; (6) a tree decomposition algorithm to solve the combinatorial problem; and (7) optimization of all parameters by determining the interaction graph within the crystal environment using symmetry operators of the crystallographic space group. Accuracies as a function of electron density of the side chains demonstrate that side chains with higher electron density are easier to predict than those with low‐electron density and presumed conformational disorder. For a testing set of 379 proteins, 86% of χ1 angles and 75% of χ1+2 angles are predicted correctly within 40° of the X‐ray positions. Among side chains with higher electron density (25–100th percentile), these numbers rise to 89 and 80%. The new program maintains its simple command‐line interface, designed for homology modeling, and is now available as a dynamic‐linked library for incorporation into other software programs. Proteins 2009. © 2009 Wiley‐Liss, Inc.