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181.
Ginette Ratovo Jean‐Pierre Souchard Pascale Urizzi Yvon Coulais Franoise Nepveu Etienne Hollande 《应用有机金属化学》2004,18(1):1-8
Pancreatic cancer has an extremely poor prognosis, due, in part, to lack of methods for early diagnosis. The present study was designed to evaluate the potential of labeling low‐density lipoprotein (LDL) with a radionuclide using a lipid chelating agent, bis(stearylamide) of diethylenetriaminepentaacetic acid (L), to detect pancreatic tumors by gamma‐scintigraphy. Previous studies indicated that the difficulty of visualization of pancreatic tumors was due to their poor vascularization. This study compares the ability of two radiotracers, 111In–L–LDL and 153Gd–L–LDL to target highly vascularized rat pancreatic tumors (AR4‐2J) implanted in nude mice. Biodistribution studies showed that the tumor uptake of 111In–L–LDL and 153Gd–L–LDL tracers was twofold and fivefold higher respectively than with the controls (111In citrate and 153Gd citrate respectively). These tracers would thus be suitable for scintigraphic imaging. We show here that LDL could be employed as a delivery system for tracers such as 111In or 153Gd when these two radionuclides are complexed by a lipid‐chelating anchor, and that 111In–L–LDL and 153Gd–L–LDL enabled better visualization of the pancreatic tumor tissues, with a better result with 153Gd–L–LDL. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
182.
P. Budrugeac J. M. Criado F. J. Gotor J. Malek L. A. Prez‐Maqueda E. Segal 《国际化学动力学杂志》2004,36(6):309-315
The isoconversional method suggested by Friedman and the invariant kinetic parameters method (IKP) were used in order to examine the kinetics of the nonisothermal crystallization of (GeS2)0.3(Sb2S3)0.7. The objective of the paper is to show the usefulness of the IKP method both for determining the activation parameters as well as the model of the investigated process. It was shown that the kinetic triplet [(E, A, f(α), where E is the activation energy, A is the preexponential factor, and f(α) is the differential function of conversion], which results through the application of the IKP method, depends on the set of kinetic models considered. For different sets of kinetic models, proportional values of f(α) are obtained. A criterion for the selection of this set, the use of which lead to the true kinetic triplet corresponding to the analyzed process (E = 163.2 kJ mol?1; A = 2.47 × 1012 min?1 and the Avrami‐Erofeev model, Am, for m = 2.5–2.6 was suggested. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 309–315, 2004 相似文献
183.
In this article, the linear and nonlinear shear rheological behaviors of polylactide (PLA)/clay (organophilic‐montmorillonite) nanocomposites (PLACNs) were investigated by an Advanced Rheology Expanded System rheometer. The nanocomposites were prepared by master batch method using a twin‐screw extruder with poly(ε‐caprolactone) (PCL) as a compatibilizer. The presence of org‐MMT leads to obvious pseudo‐solid‐like behaviors of nanocomposite melts. The behaviors caused by the formation of a “percolating network” derived from the reciprocity among the strong related sheet particles. Therefore, the storage moduli, loss moduli, and dynamic viscosities of PLACNs show a monotonic increase with MMT content. Nonterminal behaviors exists in PLACNs nanocomposites. Besides the PLACNs melts show a greater shear thinning tendency than pure PLA melt because of the preferential orientation of the MMT layers. Therefore, PLACNs have higher moduli but better processibility compared with pure PLA. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3189–3196, 2007 相似文献
184.
The crystallization behavior of miscible syndiotactic polystyrene (sPS) and atactic polystyrene (aPS) blends with different sPS/aPS weight ratios was investigated in supercritical CO2 by using Fourier‐transform infrared spectroscopy, differential scanning calorimetry, and wide‐angle X‐ray diffraction. Supercritical CO2 and aPS exhibited different effects on the conformational change of sPS and competed with each other. Increasing the content of amorphous aPS in the blends made its effect on the conformational change of sPS gradually surpass that of supercritical CO2. Supercritical CO2 favored the formation of the helical conformation of sPS in lower temperature range and the all trans planar conformation in higher temperature range, instead of forming the latter one only in higher temperature range in ambient atmosphere. However, increasing aPS content in the blends pushed the range for forming the helical conformation to lower temperature and made the all trans planar conformation dominant in aPS/sPS 25/75 blend after treating in supercritical CO2 above 60 °C. The all trans planar zigzag conformation was more favorable than the helical conformation after mixing aPS in sPS in supercritical CO2. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1755–1764, 2007 相似文献
185.
Kuan‐Wei Lee Hong‐Cheu Lin 《Journal of polymer science. Part A, Polymer chemistry》2007,45(20):4564-4572
A series of new liquid crystalline homopolymers, copolymers, and block copolymers were polymerized from styrene‐macroinitiator ( SMi ) and methacrylates with pendent 4,4′‐bis(biphenyl)fluorene ( M1 ) and biphenyl‐4‐ylfluorene ( M2 ) groups through atom transfer radical polymerization (ATRP). The number‐average molecular weights (Mn) of polymers P1 ‐ P4 were 10,007, 14,852, 6,275, and 10,463 g mol?1 with polydispersity indices values of 1.21, 1.15, 1.31, and 1.22, respectively. All polymers exhibit the nematic phase. The thermal, mesogenic, and photoluminescent properties of all polymers were investigated. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4564–4572, 2007 相似文献
186.
Nathalie Charton Achim Feldermann Alexander Theis Martina H. Stenzel Thomas P. Davis Christopher Barner‐Kowollik 《Journal of polymer science. Part A, Polymer chemistry》2004,42(21):5559-5559
The original article to which this Erratum refers was published in J Polym Sci Part A: Polym Chem (2004) 42(20) 5170–5179. No abstract. 相似文献
187.
Violetta Patroniak Wanda Radecka‐Paryzek Maciej Kubicki 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(9):o511-o513
The structure of a trifluoromethanesulfonate salt of a nontypical triply protonated linear tetramine, C7H23N43+·3CF3SO3−, with a layered crystal structure is presented. One N atom remains unprotonated. The conformation of the cation is enforced by intra‐ and intermolecular hydrogen bonds. The crystal structure is built of ca 10 Å deep layers, within which cations and anions are hydrogen bonded. Each layer is only weakly bound to its neighbours. This study shows a rare example of an unsymmetrically protonated polyamine and the relation between the lack of protonation, intramolecular hydrogen bonding and the conformation of the cation. 相似文献
188.
We prove that the renormalized solutions of the Boltzmann equation considered in a bounded domain with different types of (kinetic) boundary conditions converge to the Stokes‐Fourier system with different types of (fluid) boundary conditions when the main free path goes to zero. This extends the work of F. Golse and D. Levermore [9] to the case of a bounded domain. © 2003 Wiley Periodicals, Inc. 相似文献
189.
Zhi‐Yong Huang Jin‐Can Shen Zhi‐Xia Zhuang Xiao‐Ru Wang Frank S. C. Lee 《应用有机金属化学》2004,18(6):255-261
Cinnabar, as one of the most widely used mineral drugs in traditional Chinese medicines, has been proven to have prominent curative effects in clinical use for more than 2000 years. But the safety and toxicity of the drug has been under constant debate in clinic usage. Metallothionein (MT) contains about 30% of cysteine in the molecule, and plays an important detoxification role against heavy metals. In this study, it was used as a biomarker to assess mercurial accumulation in rats fed orally with cinnabar. After feeding rats with cinnabar by gastric gavage at different dosages and at different times, the distribution of heavy metals (including mercury, copper and zinc) and MT was investigated among rat tissues, including liver, kidney, heart, brain, testis and blood. Metals and MT determinations were carried out using inductively coupled plasma mass spectrometry (ICP‐MS) and a modified mercury saturation assay technique respectively. The results indicated that mercury was easily accumulated in the tissues of rats exposed to cinnabar, especially in kidney. For example: at a feeding dosage of 5 g kg?1 (bw) for 4 weeks, the mercury concentrations in kidney were 13, 8.7, 21.6 and 26 times those in liver, testis, brain and heart respectively; and at 2.5 g kg?1 (bw) for 2 weeks, the mercury concentrations in kidney were 21, 2.1, 3 and 21 times those in liver, testis, brain and heart respectively. In addition, mercury in kidney and liver of all cinnabar groups was significantly higher than that of the control group (P < 0.01). A high positive correlation observed between MT concentrations and mercury levels in both liver and kidney (R2 = 0.9299, P < 0.02 for liver; R2 = 0.9923, P < 0.0008 for kidney) indicated that MT could be used as a biomarker for mercury in tissues. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
190.
A numerical simulation is performed to investigate the flow induced by a sphere moving along the axis of a rotating cylindrical container filled with the viscous fluid. Three‐dimensional incompressible Navier–Stokes equations are solved using a finite element method. The objective of this study is to examine the feature of waves generated by the Coriolis force at moderate Rossby numbers and that to what extent the Taylor–Proudman theorem is valid for the viscous rotating flow at small Rossby number and large Reynolds number. Calculations have been undertaken at the Rossby numbers (Ro) of 1 and 0.02 and the Reynolds numbers (Re) of 200 and 500. When Ro=O(1), inertia waves are exhibited in the rotating flow past a sphere. The effects of the Reynolds number and the ratio of the radius of the sphere and that of the rotating cylinder on the flow structure are examined. When Ro ? 1, as predicted by the Taylor–Proudman theorem for inviscid flow, the so‐called ‘Taylor column’ is also generated in the viscous fluid flow after an evolutionary course of vortical flow structures. The initial evolution and final formation of the ‘Taylor column’ are exhibited. According to the present calculation, it has been verified that major theoretical statement about the rotating flow of the inviscid fluid may still approximately predict the rotating flow structure of the viscous fluid in a certain regime of the Reynolds number. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献