MR signal change in venous thrombus relates organizing process and thrombolytic response in rabbit

Venous thrombus is subsequently organized and replaced by fibrous connective tissue. However, the sequential changes in venous thrombi are not reliably detected by current noninvasive diagnostic techniques. The purpose of this study is to reveal whether magnetic resonance (MR) can detect venous thrombus, define thrombus age and predict thrombolytic responses. Thrombus in the rabbit jugular vein was imaged with a 1.5-T MR system at 4 h and at 1, 2 and 4 weeks using three-dimensional (3D) fast asymmetric spin echo T2-weighted (T2W) and 3D-gradient echo T1-weighted (T1W) sequences. The jugular veins were histologically assessed at each time point. Magnetic resonance imaging (MRI) was also performed in vivo before and 30 min after tissue plasminogen activator (t-PA) administration. The thrombi in MRI were comparable in size to histological sections. The signal intensity (SI) of thrombi at 4 h was heterogeneously high or low on T2W or T1W images, respectively. The SI of thrombi on T2W images decreased time-dependently, but increased on T1W images at 1 and 2 weeks. Morphological analysis showed time-dependent decreases in erythrocyte, platelet and fibrin areas and time-dependent increases in smooth muscle cell, macrophage, collagen and iron areas. The t-PA administration significantly decreased thrombus volume at 4 h but not at 1, 2 and 4 weeks. Venous thrombosis can be reliably and noninvasively detected by MRI. Measurement of SI might support assessments of thrombus age and thrombolytic response.     

Highly regioselective hydroselenation and double-bond isomerization of terminal alkynes with benzeneselenol catalyzed by bis(triphenylphosphine)palladium(II) dichloride

Bis(triphenylphosphine)palladium(II) dichloride (PdCl₂(PPh₃)₂) catalyzes regioselective addition of benzeneselenol to terminal alkynes and the subsequent double-bond isomerization to afford the corresponding internal alkenyl selenides in good yields.     

Spontaneous formation of linearly arranged microcraters on sol-gel-derived silica-poly(vinylpyrrolidone) hybrid films induced by Bénard-Marangoni convection

Complex, sophisticated surface patterns on micrometer and nanometer scales are obtained when solvent evaporates from solutions containing nonvolatile solutes dropped on a solid substrate. Such evaporation-driven pattern formation has been utilized as a fabrication process of highly ordered patterns in thin films. Here, we suggested the spontaneous pattern formation induced by Bénard-Marangoni convection triggered by solvent evaporation as a novel patterning process of sol-gel-derived organic-inorganic hybrid films. Microcraters of 1.0-1.5 μm in height and of 100-200 μm in width were spontaneously formed on the surface of silica-poly(vinylpyrrolidone) hybrid films prepared via temperature-controlled dip-coating process, where the surface patterns were linearly arranged parallel to the substrate withdrawal direction. Such highly ordered micropatterns were achieved by Bénard-Marangoni convection activated at high temperatures and the unidirectional flow of the coating solution on the substrate during dip-coating.     

Detection of 22 antiepileptic drugs by ultra-performance liquid chromatography coupled with tandem mass spectrometry applicable to routine therapeutic drug monitoring

The purpose of this study was to develop an ultra‐performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS) method of 22 antiepileptics for routine therapeutic monitoring. The antiepileptics used in the analyses were carbamazepine, carbamazepine‐10,11‐epoxide, clobazam, N‐desmethylclobazam, clonazepam, diazepam, N‐desmethyldiazepam, ethosuximide, felbamate, gabapentin, lamotrigine, levetiracetam, N‐desmethylmesuximide, nitrazepam, phenobarbital, phenytoin, primidone, tiagabine, topiramate, valproic acid, vigabatrin and zonisamide. After protein precipitation of 50 μL plasma with methanol, the supernatant was diluted with water or was evaporated to dryness and reconstituted with mobile phase in the case of benzodiazepines. Separation was achieved on an Acquity UPLC BEH C₁₈ column with a gradient mobile phase of 10 mm ammonium acetate containing 0.1% formic acid and methanol at a flow rate of 0.4 mL/min. An Acquity TQD instrument in multiple reaction monitoring mode with ion mode switching was used for detection. All antiepileptics were detected and quantified within 10 min, with no endogenous interference. All the calibration curves showed good linearity in the therapeutic range (r² < 0.99). The precision and accuracy values for intra‐ and inter‐assays were within ±15% except for phenobarbital and tiagabine. A good correlation was observed between the concentration of clinical samples measured by the new method described here and the conventional methods. The values of carbamazepine and phenytoin by UPLC‐MS/MS were lower than those detected by the immunoassays, which might be caused by the cross‐reaction of antibodies with their metabolites. In conclusion, we developed a simple and selective UPLC‐MS/MS method suitable for routine therapeutic monitoring of antiepileptics. Copyright © 2012 John Wiley & Sons, Ltd.     

Influence of the laser wavelength on the epitaxial growth and electrical properties of La0.8Sr0.2MnO3 films grown by excimer laser-assisted MOD

Epitaxial La_1−xSr_xMnO₃ (LSMO) films were prepared by excimer laser-assisted metal organic deposition (ELAMOD) at a low temperature using ArF, KrF, and XeCl excimer lasers. Cross-section transmission electron microscopy (XTEM) observations confirmed the epitaxial growth and homogeneity of the LSMO film on a SrTiO₃ (STO) substrate, which was prepared using ArF, KrF, and XeCl excimer lasers. It was found that uniform epitaxial films could be grown at 500 °C by laser irradiation. When an XeCl laser was used, an epitaxial film was formed on the STO substrate at a fluence range from 80 to 140 mJ/cm² of the laser fluence for the epitaxial growth of LSMO film on STO substrate was changed. When the LaAlO₃ (LAO) substrate was used, an epitaxial film was only obtained by ArF laser irradiation, and no epitaxial film was obtained using the KrF and XeCl lasers. When the back of the amorphous LSMO film on an LAO substrate was irradiated using a KrF laser, no epitaxial film formed. Based on the effect of the wavelength and substrate material on the epitaxial growth, formation of the epitaxial film would be found to be photo thermal reaction and photochemical reaction. The maximum temperature coefficient of resistance (TCR) of the epitaxial La_0.8Sr_0.2MnO₃ film on an STO substrate grown using an XeCl laser is 4.0%/K at 275 K. XeCl lasers that deliver stabilized pulse energies can be used to prepare LSMO films with good a TCR.     

Total Synthesis of the Bicyclic Depsipeptide HDAC Inhibitors Spiruchostatins A and B, 5′′‐epi‐Spiruchostatin B,FK228 (FR901228) and Preliminary Evaluation of Their Biological Activity

The bicyclic depsipeptide histone deacetylase (HDAC) inhibitors spiruchostatins A and B, 5′′‐epi‐spiruchostatin B and FK228 were efficiently synthesized in a convergent and unified manner. The synthetic method involved the following crucial steps: i) a Julia–Kocienski olefination of a 1,3‐propanediol‐derived sulfone and a L ‐ or D ‐malic acid‐derived aldehyde to access the most synthetically challenging unit, (3S or 3R,4E)‐3‐hydroxy‐7‐mercaptohept‐4‐enoic acid, present in a D ‐alanine‐ or D ‐valine‐containing segment; ii) a condensation of a D ‐valine‐D ‐cysteine‐ or D ‐allo‐isoleucine‐D ‐cysteine‐containing segment with a D ‐alanine‐ or D ‐valine‐containing segment to directly assemble the corresponding seco‐acids; and iii) a macrocyclization of a seco‐acid using the Shiina method or the Mitsunobu method to construct the requisite 15‐ or 16‐membered macrolactone. The present synthesis has established the C5′′ stereochemistry of spiruchostatin B. In addition, HDAC inhibitory assay and the cell‐growth inhibition analysis of the synthesized depsipeptides determined the order of their potency and revealed some novel aspects of structure–activity relationships. It was also found that unnatural 5′′‐epi‐spiruchostatin B shows extremely high selectivity (ca. 1600‐fold) for class I HDAC1 (IC₅₀=2.4 nM ) over class II HDAC6 (IC₅₀=3900 nM ) with potent cell‐growth‐inhibitory activity at nanomolar levels of IC₅₀ values.     

Crystal growth of phosphor perovskite titanate thin films under excimer laser irradiation

Ca_0.997Pr_0.002TiO₃ (CPTO) thin films that show strong red luminescence were successfully prepared by means of an excimer laser assisted metal organic deposition (ELAMOD) process with a KrF laser at a fluence of 100 mJ/cm², a pulse duration of 26 ns, and a repetition rate of 20 Hz at 100°C in air. The CPTO films grew on the silica, borosilicate, and indium-tin-oxide (ITO) glasses. The crystallinity of the CPTO films depended on the substrates; the films were well grown on the borosilicate and ITO glasses compared to the silica glass. To elucidate the key factors for the crystallization of the CPTO films in this process, we carried out numerical simulations for the temperature variation at the laser irradiation, using a heat diffusion equation, and compared the experimental data with thermal simulations. According to the results, we have shown that a large optical absorbance of the film and a small thermal conductivity of the substrate provide effective annealing time and temperature for the crystallization of the CPTO films, and polycrystalline intermediate layer which has a large optical absorption such as the ITO also plays a key role for the nucleation of the CPTO crystals in the ELAMOD process.     

Three-dimensional eddy current calculation in multiply connected regions by using the magnetic vector potential

There are two methods of using the magnetic vector potential for three-dimensional eddy current calculations. The first method uses the continuous magnetic vector potential which accompanies a scalar potential and has the advantage that no cutting is necessary for the multiply connected region problem. The second method uses the discontinuous magnetic vector potential which accompanies no scalar potential and has the disadvantage that cutting is necessary for the multiply connected region problem. In this paper a formulation using the continuous magnetic vector potential and accompanying scalar potential is given, together with computed results for three three-dimensional multiply connected eddy current problems.     

On catenate network formation by end-linking reactions

Catenate network formation by end-linking reactions of linear chains with bifunctional regents is studied theoretically and by computer simulations. It is found that the reaction cannot reach its stationary limit, and catenate networks are never formed by this method. An alternative method that will lead to catenate networks nearly in the topological equilibrium state is proposed. It is pointed out that catenate networks are an ideal system for studying the role of entanglement in rubber elasticity. © 1993 John Wiley & Sons, Inc.