bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on the effect of degradation media on the physical and mechanical properties of porous PLGA 85/15 scaffolds
Authors: Perron Josee K. , Naguib Hani E. , Daka Joseph , Chawla Attar , Wilkins Ruth 
Published: July 2009

AbstractThis study investigates the effect of PLGA 85/15 scaffold on the cell growth and viability of a cell line, and the degradation of the scaffold in different media. The cell line used was human promyelocytic leukemia cells (HL‐60). Three different media were considered: distilled water, a phosphate buffered saline (PBS) solution, and HL‐60 cell line. Porous PLGA 85/15 scaffolds were prepared with an optimized gas foaming/salt leaching technique using a NaCl/polymer mass ratio of five, a saturation pressure of 5.52 MPa and a saturation time of 12 h. The cell growth and viability were not impaired by the presence of the scaffold. The mass change of the scaffold due to degradation over the period was varied only by 4% across all three media. The average macropore size and molecular weight decreased as the degradation time increased in each medium. The scaffolds maintained mechanical and structural integrity throughout the study in all three media over the degradation period studied, and the change of Young's modulus of the scaffold under wet condition was not significant. Overall, PBS solution most strongly affected physical and mechanical properties, followed by dH2O and HL‐60 cells. The distinct variations of the scaffold's properties using different media, demonstrated the importance of carefully selecting the medium to perform in vitro studies. The medium must replicate the actual environment where the scaffold would be used, to represent accurately the changes in properties that the scaffold would be undergoing. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
In vitro comparison of the cytotoxicity of acetal resin, heat‐polymerized resin, and auto‐polymerized resin as denture base materials
Authors: Ata Secil Ozkan , Yavuzyılmaz Hüsnü 
Published: July 2009

AbstractThis in vitro study aims to evaluate three different base materials (acetal, heat‐polymerized, and auto‐polymerized resins) on L‐929 mouse fibroblast cells over 1 h‐, 1‐, 3‐, 5‐, 7‐day periods. The hypothesis was that acetal resin would show higher cytotoxic effect than heat‐polymerized and auto‐polymerized acrylic resins, as it seems possible that residual formaldehyde might be leaching from the material into the cell culture medium. The samples were produced according to the manufacturer's protocol. Then they were placed in Dulbecco's Modified Eagle Medium/Ham's F12 (DMEM/F12) for 1 h, 1, 3, 5, 7 days. After the incubation periods, cytotoxicity of the extracts to cultured fibroblasts (L‐929) was measured by MTT assay. The degree of cytotoxicity of each sample was determined according to the reference value represented by the cells with a control. Statistical significance was determined by one‐way ANOVA. Tukey and Tamhane tests were used as a post‐hoc method to determine differences among the groups. Statistically significant difference was found among test groups at all time incubation periods (p = 0.000). The auto‐polymerized resin performed higher cytotoxic effect than heat‐polymerized resin and it was statistically significant at 1‐day period (p < 0.05). The highest cytotoxic effect of acetal resin was observed at 5‐day incubation period. In conclusion, the hypothesis was verified, since acetal resin showed more cytotoxic effect on the 3rd, 5th, and 7th days than heat‐ and auto‐polymerized resins. Cell survival rates (% of control) of acetal resin were 58, 54, and 60%, respectively. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Does longstanding nicotine exposure impair bone healing and osseointegration? An experimental study in rabbits
Authors: Gotfredsen Klaus , Lindh Christian H. , Berglundh Tord 
Published: July 2009

AbstractObjectives: The aim of this study was to analyze the effect of longstanding nicotine exposure on bone healing and osseointegration of titanium implants. Materials and Methods: 20 female rabbits received either nicotine (n = 10) or saline (n = 10) administered subcutaneously via mini‐osmotic pumps for 32 weeks. The pump delivered 6 μg/kg/min of nicotine for the animals in the test group. Blood samples were collected and plasma cotinine levels were measured monthly. Six months after the commencement of nicotine or saline administration three osteotomy preparations, one in right, femoral condyle and two in the right tibia were made. One experimental implant was placed in the femur site and one in the most distal preparation of the tibia. The remaining site in the tibia was left empty. The osteotomy preparation and implant installation procedure was repeated in the left leg of the rabbits after 2 weeks. The implants in the tibial site were subjected to removal torque test (RMT) 2 weeks later. Block biopsies of the two other osteotomy sites were prepared for histological analysis. Results: Although no differences in RMT values were found between test and control groups, there was a significant increase in RMT between 2 and 4 weeks within each group. The histomorphometric analysis of bone‐to‐implant contact and bone density in the bone defects revealed no differences between the test and the control group after 2 or 4 weeks of healing. Conclusion: Longstanding (6 months) nicotine exposure did not impair bone healing and osseointegration of titanium implants. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Evaluation of quantitative importance of egg lipids and fatty acids during embryos and larvae development in marine pelagophil teleosts: with an emphasis on Dentex dentex
Authors: Samaee Seyed‐Mohammadreza , Estévez Alicia , Giménez Gemma , Lahnsteiner Franz 
Published: July 2009

AbstractQuantitative compositin of Dentex dentex eggs lipid classes (LCs) and fatty acid (FA)s were measured and correlated to embryo and larva viability parameters (egg buoyancy, floating rate (FR), hatching rate, HR and survival rate, SR, at 0–5 days post hatch, dph) through 43 formulated models (38 using FAs, as independent variable, [R2=0.641–0.859] and 5 using LC [R2=0.459–0.739]). The sphingomyelin, phosphatidylcholine and 20:2(n–6) were significantly correlated with FR; phosphatidylserine+phosphatidylinositol with SR at 1 dph; steryl ester+waxes/triacylglycerol with HR and SR at 0 dph; 14:0 with SR at 1–5 dph; 18:1(n–9), ∑18:1, 20:5(n–3)/20:4(n–6), ∑monounsaturated FAs (MUFAs), 20:5(n–3), 22:6(n–3)/20:5(n–3) and 18:3(n–3) with SR at 2–5 dph; 20:5(n–3)+20:4(n–6) with FR and SR at 2–5 dph. It was also found that a 14:0, 18:1(n–9), ∑MUFA, 18:2(n–6), 18:3(n–3), 20:5(n–3), 22:6(n–3)/20:5(n–3) and 20:5(n–3)/20:4(n–6) equal to 3.3, 16.5, 32.5, 9, 1.3, 8, 1.5 and 7, respectively, perhaps can provide a SR at 3 and 5 dph of >70%. The results indicated the importance of the egg LCs and FAs quantitative composition for common dentex embryonic and larval development and a potential use of these factors to predict egg quality in teleosts. J. Exp. Zool. 311A:735–751, 2009. © 2009 Wiley‐Liss, Inc.
Differences in gene expression between sonoporation in tumor and in muscle
Authors: Tsai Kun‐Che , Liao Zhe‐Kang , Yang Shu‐Jyuan , Lin Win‐Li , Shieh Ming‐Jium , Hwang Lih‐Hwa , Chen Wen‐Shiang 
Published: July 2009

AbstractBackgroundUltrasound (US) is a novel and effective tool for the local delivery of genes into target tissues. US can temporarily change the permeability of a cell membrane and thus enhance the delivery of naked DNA into cells. In the present study, the efficiencies of gene expression mediated by US delivery in orthotopic liver tumor, subcutaneous tumor and muscle tissue were evaluated by changing the contrast agent concentrations and US exposure durations.MethodsPlasmid DNA coding for luciferase, interleukin‐12 or enhanced green fluorescence protein was mixed with SonoVue® and injected intratumorally or intramuscularly. The injection sites were then exposed to US (20% duty cycle and 0.4 W/cm2 intensity).ResultsThe results obtained showed that the optimal condition was 50% SonoVue® for tumors and 30% for muscle, with 10 min of US exposure. The expression levels of the transfected DNAs were in the order: muscle > subcutaneous tumor > orthotopic liver tumor.ConclusionsThe present study indicates that muscle tissue is a good target site for producing large amounts of gene products for the purpose of gene therapy. Copyright © 2009 John Wiley & Sons, Ltd.
Reversible neurochemical changes mediated by delayed intrastriatal glial cell line‐derived neurotrophic factor gene delivery in a partial Parkinson's disease rat model
Authors: Yang Xin , Mertens Birgit , Lehtonen Enni , Vercammen Linda , Bockstael Olivier , Chtarto Abdelwahed , Levivier Marc , Brotchi Jacques , Michotte Yvette , Baekelandt Veerle , Sarre Sophie , Tenenbaum Liliane 
Published: July 2009

AbstractBackgroundEfficient protection of dopaminergic neurons against a subsequent 6‐hydroxydopamine lesion by glial cell line‐derived neurotrophic factor (GDNF) gene delivery has been demonstrated. By contrast, the neurorestorative effects of GDNF administered several weeks after the toxin have been less characterized. In particular, whether these were permanent or dependent on the continuous presence of GDNF remains elusive.MethodsA tetracycline‐inducible adeno‐associated virus (AAV)‐1 vector expressing human GDNF cDNA was administered unilaterally in the rat striatum 5 weeks after 6‐hydroxydopamine. Rats were treated with doxycycline (dox) or untreated from the day of vector injection until sacrifice (4 or 14 weeks). A sub‐group was dox‐treated for 7 weeks then untreated until 14 weeks. The motor behavior was assessed by amphetamine‐induced rotations and spontaneous forelimb asymmetry. The amounts of tyrosine hydroxylase (TH), serine‐40‐phosphorylated TH (S40‐TH) and aromatic amino acid decarboxylase (AADC) proteins were compared by western blotting and the dopamine levels quantified by high‐performance liquid chromatography.ResultsDox‐dependent behavioral improvements were demonstrated 4 weeks post‐vector injection. At later time points, spontaneous partial recovery was observed in all rats, but no further improvement was found in dox‐treated animals. TH levels were significantly increased in dox‐treated rats at all time points. By contrast, striatal dopamine and S40‐TH were increased at 4 weeks, but not 14 weeks, and AADC remained unchanged. Dox withdrawal after 7 weeks, resulted in TH levels comparable to the controls at 14 weeks.ConclusionsDelayed GDNF gene delivery only transiently improved dopaminergic function. Over the long term, TH was more abundant, but not functional, and the increase was lost when GDNF gene expression was switched off. Copyright © 2009 John Wiley & Sons, Ltd.
Empirical models of UV total radiation and cloud effect study
Authors: Mateos Villán David , de Miguel Castrillo Argimiro , Bilbao Santos Julia 
Published: July 2009

AbstractSeveral empirical models of hourly ultraviolet total radiation (UVT) have been proposed in this study. Measurements of UVT radiation, 290–385 nm, have been recorded at ground level from February 2001 to June 2008 in Valladolid, Spain (latitude 41°40′N, longitude 4°50′W and 840 m a.s.l.). The empirical models have emerged due to the lack of some radiometric variables in measuring stations. Hence, good forecasts of them can be obtained from usual measures in these stations. Therefore, some advantages of the empirical models are that they allow the estimation of past missing data in the database and the forecast of future ultraviolet solar availability. In this study, reported models in the bibliography have been assessed and recalibrated. New expressions have been proposed that allow obtaining hourly values of ultraviolet radiation from global radiation measures and parameters as clearness index and relative optical air mass. The accuracy of these models has been assessed through the following statistical indices: mean bias, mean‐absolute bias and root‐mean‐square errors whose values are close to zero, below 7% and below 10%, respectively. Two new clear sky models have been used to evaluate two new parameters: ultraviolet and global cloud modification factors, which can help to understand the role of the clouds on solar radiation. The ultraviolet cloud modification factor depends on cloudiness in such a way that its value under overcast skies is half of the cloudless skies one. Exponential and potential fits are the best relationships between both cloud factors. Finally, these parameters have been used to build new UV empirical models which show low values of the statistical indices mentioned above. Copyright © 2009 Royal Meteorological Society
European snow cover extent variability and associations with atmospheric forcings
Authors: Henderson Gina R. , Leathers Daniel J. 
Published: July 2009

AbstractSnow cover in Europe represents an important component of the region's climatic system. Variability in snow cover extent can have major implications on factors such as low‐level atmospheric temperatures, soil temperatures, soil moisture, stream discharge, and energy allocation involved in the warming and melting of the snowpack. The majority of studies investigating Northern Hemisphere snow cover identify European snow cover extent as a portion of the Eurasian record, possibly masking complexities of this subset. This study explores the variability of European snow cover extent from 1967–2007, with the region in question including the area of Europe extending eastward to the Ural Mountains (60°E). Using the 89 × 89 gridded National Oceanic and Atmospheric Administration (NOAA) Northern Hemisphere weekly satellite snow cover product, area estimates of seasonal snow cover were calculated, and their relationship to gridded temperature, precipitation, and sea‐level pressure data analysed. The spatial variability of snow cover extent was also explored using geographical information systems (GIS). The combined results from both surface temperature and precipitation analyses point towards snow cover extent in Europe being primarily temperature dependent. Atmospheric variables associated with extremes in snow cover extent were investigated. Large (small) European snow extent is associated with negative (positive) 850 hPa zonal wind anomalies, negative (positive) European 1000–500 hPa thickness anomalies, and generally positive (negative) Northern European precipitation anomalies. Sea‐level pressure and 500 hPa results indicate strong associations between large (small) snow cover seasons and the negative (positive) phase of the North Atlantic Oscillation. Copyright © 2009 Royal Meteorological Society
Effects of urease and nitrification inhibitors added to urea on nitrous oxide emissions from a loess soil
Authors: Khalil Mohammad I. , Gutser Reinhard , Schmidhalter Urs 
Published: July 2009

AbstractUrea fertilizer‐induced N2O emissions from soils might be reduced by the addition of urease and nitrification inhibitors. Here, we investigated the effect of urea granule (2–3 mm) added with a new urease inhibitor, a nitrification inhibitor, and with a combined urease inhibitor and nitrification inhibitor on N2O emissions. For comparison, the urea granules supplied with or without inhibitors were also used to prepare corresponding supergranules. The pot experiments without vegetation were conducted with a loess soil at (20 ± 2)°C and 67% water‐filled pore space. Urea was added at a dose of 86 kg N ha–1 by surface application, by soil mixing of prills (<1 mm) and granules, and by point‐placement of supergranules (10 mm) at 5 cm soil depth. A second experiment was conducted with spring wheat grown for 70 d in a greenhouse. The second experiment included the application of urea prills and granules mixed with soil, the point‐placement of supergranules and the addition of the urease inhibitor, and the combined urease plus nitrification inhibitors at 88 kg N ha–1. In both experiments, maximum emissions of N2O appeared within 2 weeks after fertilization. In the pot experiments, N2O emissions after surface application of urea were less (0.45% to 0.48% of total fertilization) than from the application followed by mixing of the soil (0.54% to 1.14%). The N2O emissions from the point‐placed‐supergranule treatment amounted to 0.64% of total fertilization. In the pot experiment, the addition of the combined urease plus nitrification inhibitors, nitrification inhibitor, and urease inhibitor reduced N2O emissions by 79% to 87%, 81% to 83%, and 15% to 46%, respectively, at any size of urea application. Also, the N2O emissions from the surface application of the urease‐inhibitor treatment exceeded those of the granules mixed with soil and the point‐placed‐supergranule treatments receiving no inhibitors by 32% to 40%. In the wheat growth experiment, the N2O losses were generally smaller, ranging from 0.16% to 0.27% of the total fertilization, than in the pot experiment, and the application of the urease inhibitor and the combined urease plus nitrification inhibitors decreased N2O emissions by 23% to 59%. The point‐placed urea supergranule without inhibitors delayed N2O emissions up to 7 weeks but resulted in slightly higher emissions than application of the urease inhibitor and the urease plus nitrification inhibitors under cropped conditions. Our results imply that the application of urea fertilizer added with the combined urease and nitrification inhibitors can substantially reduce N2O emissions.
Cultural comparison of tourists' safety perception in relation to trip satisfaction
Authors: Tasci Asli D. A. , Boylu Yasin 
Published: July 2009

AbstractAlthough safety and security are seen as a priori for a prosperous tourism industry in any destination, safety and security perception and its influence on tourist behaviour have received limited empirical attention from researchers. This study investigated tourists' perception of the safety and security of a destination in relation to the level of satisfaction with their trip, using Turkey and its visitors as a case in point. The stepwise regression analysis was employed to investigate the relationship between trip satisfaction, safety and security‐related variables, existence of product or service failure, and selected demographic variables. Results showed that positive perception of Turkey's hygiene and health, and safety and security helped visitors to have greater trip satisfaction, especially if they stayed longer and enjoyed their trip without any product or service failure; however, German tourists and tourists with a secondary school degree are more likely to have less trip satisfaction. Practical implications and future research suggestions are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
The impact of sudden gains in cognitive behavioral therapy for posttraumatic stress disorder
Authors: Kelly Kacie A. , Rizvi Shireen L. , Monson Candice M. , Resick Patricia A. 
Published: July 2009

AbstractThis study investigated sudden gains, i.e., rapid and stable improvements, in posttraumatic stress disorder (PTSD) symptoms that may occur in cognitive–behavioral therapy. Twenty‐nine of 72 participants (39.2%) experienced a sudden gain during treatment. Mixed model ANOVAs analyzed sudden gains impact on clinician‐rated PTSD symptom severity, patient‐rated PTSD symptom severity, and patient‐rated depressive symptom severity. Sudden gains in PTSD symptomology were associated with greater reductions in PTSD symptom severity for the avoidance/numbing and hyperarousal symptom clusters at posttreatment. By 6‐month follow‐up, the sudden gains group had maintained those reductions in symptoms, but the nonsudden gains group had achieved equal reductions in symptom severity. Participants experiencing sudden gains on PTSD measures had lower depression severity at posttreatment and follow‐up.
Penetration of CO2 laser into the otic capsule using a hand‐held, flexible‐fiber delivery system
Authors: Majdani Omid , Wittkopf Justin , Dietrich Mary S. , Labadie Robert F. 
Published: July 2009

AbstractBackground and ObjectiveRecently, a new, flexible‐fiber, CO2 laser delivery system has been FDA‐cleared for clinical use. However, for otologic surgery, no data have been reported correlating power settings to depth of penetration into the otic capsule—the bone that covers the inner ear. This was the goal of our study.Study Design/Materials and MethodsEight cadaveric temporal bones were procured as per our institution's protocols. For each specimen, nine different laser holes were burned into the otic capsule using the flexible‐fiber CO2 laser delivery system. Power settings were varied from 10 to 20 W in 2 W increments, and duration of exposure was 100, 200, 300, 400, or 600 milliseconds. Each setting (power and duration) was tested on two specimens. Following laser exposure, each specimen was scanned in a microCT scanner, and the depth of penetration measured from these images.ResultsOf the 72 laser shots, 8 were excluded due to double hits (4), oblique hits (3), or complete penetration (1). After excluding these 8, bone penetration was found to vary from 160 to 670 µm based on power and time settings. Spearman analysis on ranked data showed that time had a greater impact on depth than power. The correlation coefficients for time and power were 0.84 (P = 0.013) and 0.40 (P<0.001), respectively.ConclusionThe flexible‐fiber CO2 laser is effective for otic capsule ablation in this model. High power setting and long pulse duration can lead to complete penetration of the otic capsule potentially causing damage of underlying structures such as the facial nerve, horizontal semicircular canal, and cochlea. Lasers Surg. Med. 41:509–513, 2009. © 2009 Wiley‐Liss, Inc.
Establishment and characterization of a cancer cell line derived from an aggressive childhood liver tumor
Authors: Chen Tina T.‐L. , Rakheja Dinesh , Hung Jaclyn Y. , Hornsby Peter J. , Tabaczewski Piotr , Malogolowkin Marcio , Feusner James , Miskevich Frank , Schultz Roger , Tomlinson Gail E. 
Published: July 2009

AbstractBackgroundHepatoblastoma is a rare malignancy of childhood. The scarcity of adequate cell models has limited our understanding of this tumor. Here we describe and characterize a new human liver tumor cell line, Hep293TT, derived from an aggressive childhood hepatoblastoma.ProceduresHep293TT cells were established using primary tumor tissues from a 5‐year‐old Caucasian female child. This cell line has been maintained for more than 34 months and over 20 subcultures, and was characterized by histopathology, ELISA, genotype, cytogenetics, CGH array, immunohistochemistry, and molecular sequence analyses.ResultsCells were confirmed to originate from parental tumor cells, secrete α‐fetoprotein, and express hepatic markers and β‐catenin. Hep293TT cells were able to form colonies in soft agar. Tumorigenicity was demonstrated by induction of solid tumors after subrenal capsule injection in immunodeficient mice. Hep293TT cells demonstrated a highly aneuploid karyotype, and a whole genome CGH analysis revealed chromosomal imbalances in every chromosome. Allelotype analysis demonstrated loss of alleles at distal 11p15.5 as is typical of embryonal tumors. Both Hep293TT cells and the primary tumor contain a deletion of 351 nucleotides in β‐catenin, as has been seen in other hepatoblastoma tumors. The cell line expressed β‐catenin protein in both full‐length and partially deleted forms, and expressed NOTCH2 protein characteristic of hepatoblasts. No mutation was detected in the APC, MYH, MLH1, or MSH2 genes.ConclusionThis cell line, Hep293TT, is a valuable resource for the study of childhood liver cancer and may potentially provide a tool in the development of new agents. Pediatr Blood Cancer 2009;53:1040–1047. © 2009 Wiley‐Liss, Inc.