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21.
The aim of the present work is the study of some physicochemical properties of two current commercial dental self‐curing two component composites, i.e., of Concise? (3M?, Dental Products, St. Paul, USA), and Alfacomp (VOCO GmbH, Germany). Based on their filler type Concise is characterized as “conventional” or “macrofilled” composite and Alfacomp as “hybrid.” The resin matrix of Concise is a copolymer of 2‐bis[4‐2‐hydroxy‐3‐(methacryloxy)‐propyl]phenyl propane (Bis‐GMA)/triethyleneglycol dimethacrylate, while that of Alfacomp a homopolymer of Bis‐GMA. The composites were prepared in accordance with the manufacturers' instructions by mixing equal amounts of the two components at room temperature. The degree of conversion of double bonds of resin matrix during curing was determined in thin film of composites using FTIR transmission spectroscopy. The degree of conversion of Concise and Aflacomp was found to be correspondingly (73.63 ± 4.33)% and (47.75 ± 1.80)% after a day‐polymerization. Sorption, solubility, and volumetric change were determined after storage of composites in water or ethanol/water solution 75 vol % at 37°C (a good food/oral simulating fluid) for 30 days. These properties for both composites were higher in ethanol/water solution than in water. Also these properties for Concise were lower than those for Alfacomp in both liquids. Thermal stability of composites was studied by thermogravimetric analysis which performed in air atmosphere from 50 to 800°C. This analysis of composites showed the degradation of their resin matrix in three steps. The organic resin content of Concise was found to be 18.0% w/w and that of Alfacomp 20.1% w/w. Concise showed generally better properties than Alfacomp. This behavior must due to the differences in the chemical structure of the organic resin matrix and the type of inorganic filler. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
22.
Aprahamian M Bour G Akladios CY Fylaktakidou K Greferath R Soler L Marescaux J Egly JM Lehn JM Nicolau C 《Chembiochem : a European journal of chemical biology》2011,12(5):777-783
Myo-inositol trispyrophosphate (ITPP), a synthetic allosteric effector of hemoglobin, increases the regulated oxygen-releasing capacity of red blood cells (RBCs), leading to suppression of hypoxia-inducible factor 1α (HIF-1α) and to down-regulation of hypoxia-inducible genes such as vascular endothelial growth factor (VEGF). As a consequence, tumor growth is markedly affected. The effect of weekly intravenous injection of ITPP on an orthotopic, syngenic rat hepatocellular carcinoma (HCC) model was compared to that for untreated animals and animals subjected to conventional Doxorubicin chemotherapy. The longitudinal examination of HCC was performed by microCT imaging, and the cellular and molecular changes were evaluated by histology and Western blotting analysis of HIF-1α, VEGF, and caspase-3 gene expression in the tumor and in the surrounding liver. Hematologic impact was evaluated by blood cell-count measurement and determination of P50 (oxygen partial pressure for a 50 % oxygen saturation of hemoglobin). The HCC evaluation by microCT revealed a high potency of ITPP for tumor growth inhibition, thus allowing long-term survival and even cure of almost all the treated animals. The P50 value of hemoglobin in RBCs underwent a shift of 30 % following ITPP injection. Under these conditions, HIF-1α activity was strongly decreased, VEGF expression was down-regulated, and apoptosis was induced in HCC and surrounding liver cells, as indicated by Caspase-3 expression. ITPP did not affect hematologic parameters during treatment. The observations of in vivo tumor eradication suggest a significant clinical potential for ITPP in cancer therapy. 相似文献
23.
Polyphosphorylated and perphosphorylated hexopyranose monosaccharides and disaccharides were synthesized from parent or partially protected carbohydrates as potential allosteric effectors of hemoglobin. A study toward the construction of seven- and eight-membered cyclic pyrophosphates was also performed on the sugars which had the proper orientation, protection, and number of phosphates. All final compounds were tested for their efficiency on oxygen release from human hemoglobin. Several compounds presented higher potency than myo-inositol hexakisphosphate, which is the most efficient of the known allosteric effectors of hemoglobin. Structure-activity relationships were analyzed. The affinity and efficiency depend on the number of phosphates attached to the carbohydrate skeleton and are related primarily to the number of negative charges present. Other effects operate, but play a lesser role. 相似文献
24.
Konstantina Trigka Periklis Dousdampanis Christopher T. Chan 《Hemodialysis international. International Symposium on Home Hemodialysis》2013,17(2):309-312
We present a patient with primary systemic AL‐amyloidosis, who stabilized hemodynamically on nocturnal hemodialysis (NHD). The NHD allowed a significant reduction in ultrafiltration rates which likely underlies the procedural tolerability. It also provided an increase in urea clearance, better control of serum phosphorus levels without the use of any binders, and normalization of blood pressure despite the discontinuation of all antihypertensive agents. Given the autonomic derangements associated with AL‐amyloidosis pathophysiology and the clinical benefits of NHD on hemodynamic stability, the use of intensive hemodialysis may be considered for the management of patients with unstable hemodynamic profiles. 相似文献
25.
Nikolaos Nikolaou Panagiotis Dimitrakis Pascal Normand Vassilios Ioannou-Sougleridis Konstantinos Giannakopoulos Konstantina Mergia Kaupo Kukli Jaakko Niinistö Mikko Ritala Markku Leskelä 《Solid-state electronics》2012
In this work we report the performance of the SiO2/Si3N4/HfO2 and SiO2/Si3N4/ZrO2 stacks with emphasis on the influence of atomic layer deposition chemistry used for forming the HfO2 and ZrO2 blocking layers. Two Hf precursors were employed – tetrakis(ethylmethylamino)hafnium (TEMAH) and bis(methylcyclopentadienyl)methoxymethyl hafnium (HfD-04). For ZrO2, tetrakis(ethylmethylamino)zirconium (TEMAZ) and bis(methylcyclopentadienyl)methoxymethyl zirconium (ZrD-04) were used as metal precursors. Ozone was used as the oxygen source. The structural characteristics of the stacks were examined by transmission electron microscopy and grazing incidence X-ray diffraction. The electrical properties of the stacks were studied using platinum-gated capacitor structures. The memory performance of the stacks was evaluated by write/erase (W/E) measurements, endurance and retention testing. Endurance measurements revealed the most important difference between the stacks. The films grown from TEMAH and TEMAZ could withstand a significantly higher number of W/E pulses (>3 × 105 in the 10 V/?11 V, 10 ms regime), in comparison to the stacks made from HfD-04 and ZrD-04 precursors (<5 × 103 W/E cycles). This difference in endurance characteristics is attributed mainly to the different deposition temperatures suited for these two precursors and the nature of the layer formed at the Si3N4/HfO2 and the Si3N4/ZrO2 interfaces. 相似文献
26.
Konstantina Lambrinou Jef Vleugels Aldo R. Boccaccini 《Journal of the American Ceramic Society》2007,90(2):590-597
This work addresses the formation conditions and stability of a celsian-cordierite eutectic structure produced during the crystallization of a barium magnesium aluminosilicate (BMAS) glass–ceramic with the Ba-osumilite stoichiometry. The melt-derived BMAS glass–ceramic was pulverized and subsequently hot pressed to produce sintered powder compacts, some of which were subjected to post-sintering heat treatments in air. The study of the devitrified BMAS glass revealed that a metastable celsian-cordierite eutectic structure resulted from the prolonged annealing of the BMAS glass–ceramic between 860° and 1000°C. The celsian-cordierite eutectic structure transformed to the thermodynamically stable Ba-osumilite phase when annealed at temperatures >1000°C. 相似文献
27.
Triga K Dousdampanis P Aggelakou-Vaitis S Gellner K 《Hemodialysis international. International Symposium on Home Hemodialysis》2012,16(1):109-112
New-onset psoriasis is extremely rare in hemodialysis (HD) patients, and several trials of dialysis therapies (HD and peritoneal dialysis) in psoriasis have indicated remarkable improvement in skin lesions and well-being even in patients without renal impairment. We describe a patient who developed severe psoriasis despite undergoing chronic maintenance hemodialysis for 5 years and was treated successfully with oral cyclosporin A. 相似文献
28.
29.
Aristidis Golfinopoulos Magdalini SoupioniNikolaos Kopsahelis Konstantina TsaousiAthanasios A. Koutinas 《Food chemistry》2012
Lactose uptake rate by kefir yeast, immobilized on tubular cellulose and gluten pellets during fermentation of lactose and whey, was monitored using 14C-labelled lactose. Results illustrated that, in all cases, lactose uptake rate was strongly correlated with fermentation rate and the fermentation’s kinetic parameters were improved by kefir yeast entrapped in tubular cellulose. As a result, twofold faster fermentations were achieved in comparison with kefir yeast immobilized on gluten. This is probably due to cluster and hydrogen bonds formation between cellulose and inhibitors, such as Ca++ and generated lactic acid, by which they leave the liquid medium. The findings, regarding the promotional effect of cellulose, seem promising for application in industrial whey fermentations. 相似文献
30.
In the digital economy, the volume, variety and availability of data produced in myriad forms from a diversity of sources has become an important resource for competitive advantage, innovation opportunity as well as source of new management challenges. Building on the theoretical and empirical foundations of the traditional manufacturing Supply Chain (SC), which describes the flow of physical artefacts as raw materials through to consumption, we propose the Data Supply Chain (DSC) along which data are the primary artefact flowing. The purpose of this paper is to outline the characteristics and bring conceptual distinctiveness to the context around DSC as well as to explore the associated and emergent management challenges and innovation opportunities. To achieve this, we adopt the systematic review methodology drawing on the operations management and supply chain literature and, in particular, taking a framework synthetic approach which allows us to build the DSC concept from the pre-existing SC template. We conclude the paper by developing a set of propositions and outlining an agenda for future research that the DSC concept implies. 相似文献