Gd-complexes of DTPA-bis(amide) conjugates of tranexamic acid and its esters with high relaxivity and stability for magnetic resonance imaging

The synthesis and the characterization of a series of DTPA-bis(amide) conjugates of tranexamic acid (L1), its esters (L2-L6), and their Gd(III) complexes of the type [Gd(L)(H2O)].nH2O (L = L1-L6) are described. Except for the case of , all Gd-complexes exhibit greatly enhanced R1 relaxivity. Highest R1 reaches up to 12.9 mM(-1) s(-1) for [Gd(L2)(H2O)]. Such high relaxivity is reflected in the intensity enhancement of the in vivo MRI study on H-ras transgenic mice bearing hepatic tumor when employing [Gd(L2)(H2O)] as an MRI contrast agent. Thermodynamic stability constants, conditional stability constants, and the pM values demonstrate higher stability of [Gd(L)(H2O)].nH2O (L =L1-L6) than Omniscan under physiological conditions. The MTT assay performed on these complexes reveals cytotoxicity as low as that for Omniscan in the concentration range required to obtain intensity enhancement in the in vivo MRI study.     

Extraction of formic and acetic acids from aqueous solution by dynamic headspace-needle trap extraction temperature and pH optimization

A combined method of dynamic headspace-needle trap sample preparation and gas chromatography for the determination of formic and acetic acids in aqueous solution was developed in this study. A needle extraction device coupled with a gas aspirating pump was intended to perform sampling and preconcentration of target compounds from aqueous sample before gas chromatographic analysis. The needle trap extraction (NTE) technique allows for the successful sampling of short chain fatty acids under dynamic conditions while keeping the headspace (HS) volume constant. Two important parameters, including extraction temperature and effect of acidification, have been optimized and evaluated using the needle trap device. The method detection limits for the compounds estimated were 87.2microg/L for acetic acid and 234.8microg/L for formic acid in spite of the low flame ionization detection response for formic acid and its low Henry's law constant in aqueous solution. Precision was determined based on the two real samples and ranged between 4.7 and 10.7%. The validated headspace-needle trap extraction method was also successfully applied to several environmental samples.     

Novel single-crystal-to-single-crystal anion exchange and self-assembly of luminescent d(10) metal (Cd(II), Zn(II), and Cu(I)) complexes containing C(3)-symmetrical ligands

Ligands L1 and L2' (L1=N,N',N'-tris(4-pyridyl)trimesic amide, L2'=N,N',N'-tris(3-pyridinyl)-1,3,5-benzenetricarboxamide) belonging to an interesting family of tripyridyltriamides with C(3)-symmetry have been utilized to construct 3D porous or hydrogen-bonded frameworks. Through a novel single-crystal-to-single-crystal anion-exchange process, [Cd(L1)(2)(ClO(4))(2)](n) (1c) can be obtained from [Cd(L1)(2)Cl(2)](n) (1b) in the presence of ClO(4)(-) anions. This anion-exchange process is highly selective and only the substitution of Cl(-) by ClO(4)(-) or PF(6)(-) could be realized; Cl(-) was found not to be substituted by BPh(4)(-). This demonstrates that the exchange process depends on the size of the anions in relation to the size of the cavities in the host material (ca. 7.5 A). In addition, the anion-exchange properties of 1 b have also been investigated by means of powder X-ray diffraction (PXRD), elemental analysis (EA), and infrared absorption spectroscopy (IR). Structurally, [Zn(L1)(NO(3))(2)](n)(2) consists of a 2D coordination network with five-coordinate Zn(II) ions. Surprisingly, different trigonal-bipyramidal Zn(II) ions propagate to form distinct respective sheet structures, A and B, which are packed in an A-B-A-B manner in the crystal lattice, and these are hydrogen-bonded to give a 3D extended framework. The molecular structure of [CuI(L2')](n)(3) shows that the Cu(I) ion adopts a distorted tetrahedral geometry, and 3 also forms a 2D coordination network. Significantly, this 2D coordination network is further assembled into a remarkable 3D homochiral framework through triple hydrogen bonding and pi...pi interactions. All of these 3D coordination polymers and/or hydrogen-bonded frameworks are luminescent in the solid state, and their solid-state luminescent properties have been investigated at room temperature and/or at 77 K.     

Cosmological natural selection as the explanation for the complexity of the universe

A critical review is given of the theory of cosmological natural selection. The successes of the theory are described, and a number of published criticisms are answered. An observational test is described which could falsify the theory.     

The potential role of ultrasound in differentiating solid and cystic swellings of the true vocal fold

This study was designed to investigate the potential role of ultrasound in the diagnosis of cysts of the true vocal fold. Materials and Methods: Grayscale ultrasound of the larynx was carried out in 29 patients with a swelling of the true vocal fold and dysphonia. The findings were then compared with those at subsequent microlaryngoscopy, in the majority of cases. Results and Conclusions: Whereas preoperative laryngeal ultrasound correctly predicted the surgical findings of a cystic lesion in only 5 of 11 cases, it correctly identified that no cyst was present in 15 of 16 instances when this had been queried. This study suggests that ultrasound may have some role in investigation of unilateral vocal fold pathology, but that further fine-tuning of the technique may be necessary.     

Structure,transport and magnetic properties of the double perovskite (Ca<Subscript>2-2x</Subscript>Sr<Subscript>2x</Subscript>)FeMoO<Subscript>6</Subscript>

In this paper we report the results of a detailed investigation of the double perovskite (Ca_2-2xSr_2x)FeMoO₆ system. Chemical size effects on structural, electrical, and magnetic properties caused by the substitution of isovalent, larger Sr ions into the smaller Ca sites, resulting in (Ca_2-2xSr_2x)FeMoO₆, have been examined. The compounds crystallize in the monoclinic space group P2₁/n for 0.0x<0.2, the orthorhombic space group Pbnm for 0.2x<0.4, and the tetragonal space group I4/m and I4/mmm for x0.4. Examination of the resistivity of all compounds reveals a metallic behavior which is well described by a Tⁿ dependence except for x=1.0. These n values change from 1 to 2 as T decreases lower than T_c. This is indicative of a variation in the transport mechanism at T_c. The ferrimagnetic transition temperature T_c increases with increasing x from 318 (x=0.0) to 393 K (x=1.0). For all samples, the saturation magnetization at 82 K obeys M_s3.5_B/(formula unit), compared to a theoretical spin-only moment of 4_B/(formula unit) for a perfectly ordered compound. PACS 74.25.Fy; 74.25.Ha     

Ergodicity for the Dissipative Boussinesq Equations with Random Forcing

We study the stationary measure for the two-dimensional Boussinesq equation with random forcing. We prove the ergodicity for the two-dimensional stochastically forced Boussinesq equation. We also study the Galerkin truncations of the three-dimensional Boussinesq equations under degenerate stochastic forcing. We follow closely the previous results on the stochastically forced Navier–Stokes equations.     

Resonant-cavity light-emitting diodes: quantum noise and spatial emission characteristics

We demonstrate the interplay between the intensity noise and the spatial emission characteristics of resonant-cavity light-emitting diodes. First, we find that the total aperture intensity noise exhibits a sub-shot noise behavior in a quite large pumping regime. Second, we investigate the angular, spectral, and spatial emission characteristics of the devices by controlling the shape and width of the angular intensity distribution via temperature detuning of the quantum well wavelength and the cavity resonance wavelength. Finally, the angular and aperture resolved intensity noise exhibit a super-shot noise behavior in contrast to that of the total emission. We explain this difference with anticorrelations between various radial components which increase with the temperature-tuned extension of the spatial emission. PACS 85.60.Jb; 42.50.L; 23.20.En     

Removal of 17β-estradiol by powdered activated carbon—Microfiltraion hybrid process: The effect of PAC deposition on membrane surface

The removal of 17β-estradiol (E2) was investigated in a powdered activated carbon-submerged microfiltration (PAC-MF) hybrid system to better understand the effect on the system performance of PAC deposition on the membrane. A series of experiments were carried out under various operating conditions. Although the rejection or adsorption of E2 by MF membrane itself was almost negligible, the concentration of E2 in the permeate was always lower than it was in the reactor. This is because E2 was further removed as it passed through the PAC layer deposited on the membrane. As the E2 removal efficiency by the deposited PAC was lower than that by the PAC in the bulk phase, the overall E2 removal was largely dependent on the fraction of the deposited PAC on the membrane which were influenced by operating parameters such as permeate flux, hydraulic retention time (HRT) and mixing intensity in a PAC-MF system. The effect of these parameters on the overall E2 removal rate were also determined quantitatively using model equations developed in this study.     

Simultaneous LC−UV Analysis of Mirodenafil and Its Two Main Metabolites in Rat Plasma and Urine, and in Tissue Homogenates

A simple, rapid, and reproducible isocratic reversed-phase LC method has been established for simultaneous analysis of mirodenafil and its two main metabolites, SK3541 and SK3544, in rat plasma, urine, and tissue homogenates. Samples were deproteinized with acetonitrile containing sildenafil (internal standard). The compounds were separated on a C₁₈ column with 52:48 (v/v) 0.02 m ammonium acetate buffer (pH 6)—acetonitrile as mobile phase at a flow rate of 1.4 mL min^?1. UV detection was at 254 nm and detection limits of mirodenafil, SK3541, and SK3544 in plasma were 0.03, 0.05, and 0.1 μg mL^?1, respectively. The method is applicable to pharmacokinetic studies of mirodenafil and its metabolites in rats.