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High Solubility (high + solubility)
Selected AbstractsSynthesis and Optoelectronic Properties of Nonpolar Polyrotaxane Insulated Molecular Wires with High Solubility in Organic Solvents,ADVANCED FUNCTIONAL MATERIALS, Issue 21 2008Michael J. Frampton Abstract Hydrophilic polyanionic conjugated polyrotaxanes are readily synthesized in water by Suzuki coupling, but their high polarity and ionic nature limit the potential applications of these materials. Here, we demonstrate three methods for transforming these polar polyelectrolytes into nonpolar lipophilic insulated molecular wires. A water-soluble polyfluorene- alt -biphenylene ,-cyclodextrin (CD) polyrotaxane was converted into nonpolar derivatives by methylation of the carboxylic acid groups with diazomethane and conversion of the hydroxyl groups of the CDs to benzyl ethers, trihexylsilyl ethers, benzoyl esters, and butanoate esters to yield polyrotaxanes that are soluble in organic solvents such as chloroform and cyclohexane. Elemental analysis, NMR spectroscopy, and gel permeation chromatography (GPC) data support the proposed structures of the organic-soluble polyrotaxanes. The extents of reaction of the polyrotaxane CD hydroxyl groups were 55% for trihexylsilyl chloride/imidazole; 81% for benzyl chloride/sodium hydride; 72% for benzoyl chloride/pyridine/4-dimethylaminopyridine; and 98% butanoic anhydride/pyridine/4-dimethylaminopyridine. Alkylation, silylation, and esterification increase the bulk of the encapsulating sheath, preventing interstrand aggregation, increasing the photoluminescence efficiency in the solid state and simplifying the time-resolved fluorescence decay. The organic-soluble polyrotaxanes were processed into polymer light-emitting diodes (PLEDs) from solution in nonpolar organic solvents, thereby excluding ionic impurities from the active layer. [source] Differential inhibition in vivo of ammonia monooxygenase, soluble methane monooxygenase and membrane-associated methane monooxygenase by phenylacetyleneENVIRONMENTAL MICROBIOLOGY, Issue 5 2000Sonny Lontoh Phenylacetylene was investigated as a differential inhibitor of ammonia monooxygenase (AMO), soluble methane monooxygenase (sMMO) and membrane-associated or particulate methane monooxygenase (pMMO) in vivo. At phenylacetylene concentrations >,1 µM, whole-cell AMO activity in Nitrosomonas europaea was completely inhibited. Phenylacetylene concentrations above 100 µM inhibited more than 90% of sMMO activity in Methylococcus capsulatus Bath and Methylosinus trichosporium OB3b. In contrast, activity of pMMO in M. trichosporium OB3b, M. capsulatus Bath, Methylomicrobium album BG8, Methylobacter marinus A45 and Methylomonas strain MN was still measurable at phenylacetylene concentrations up to 1000 µM. AMO of Nitrosococcus oceanus has more sequence similarity to pMMO than to AMO of N. europaea. Correspondingly, AMO in N. oceanus was also measurable in the presence of 1000 µM phenylacetylene. Measurement of oxygen uptake indicated that phenylacetylene acted as a specific and mechanistic-based inhibitor of whole-cell sMMO activity; inactivation of sMMO was irreversible, time dependent, first order and required catalytic turnover. Corresponding measurement of oxygen uptake in whole cells of methanotrophs expressing pMMO showed that pMMO activity was inhibited by phenylacetylene, but only if methane was already being oxidized, and then only at much higher concentrations of phenylacetylene and at lower rates compared with sMMO. As phenylacetylene has a high solubility and low volatility, it may prove to be useful for monitoring methanotrophic and nitrifying activity as well as identifying the form of MMO predominantly expressed in situ. [source] A pilot-scale demonstration of a membrane-based absorption- stripping process for removal and recovery of volatile organic compoundsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2001S. Majumdar A new membrane-based continuous absorption-stripping process has been developed to separate gas/vapor mixtures, such as volatile organic compounds (VOCs), from a nitrogen/air stream. Two different hollow fiber membrane modules are needed in this process to remove the VOCs. In the first module, VOC-laden nitrogen/air stream flows through the bore of the hollow fibers. A suitable absorbent liquid with a high solubility for the VOC and essentially no solubility for nitrogen/air is pumped countercurrently over the outside of the fibers. This liquid is an inert, nontoxic, and essentially nonvolatile, organic solvent. The VOCs are effectively removed from nitrogen/air to a very low level and are concentrated in the absorbent for recovery, while the absorbent is regenerated by heating and subjecting it to vacuum in a separate hollow fiber membrane module called the stripping module. A pilot-scale membrane-based absorption-stripping unit was located next to a paint spray booth at Robins Air Force Base, Warner Robins, GA. Tests were performed on slip-streams of real-time air emissions from scheduled intermittent painting operations, so the concentration of VOC in the exhaust air fluctuated with time. The VOC removal efficiency was determined as a function of the feed air flow rate and the absorbent (silicone oil) flow rate. Depending on the gas/liquid flow rates and the inlet VOC concentration, the process successfully removed as much as 95+% of the VOC present. The experimental results have been compared with theoretical predictions. [source] Material Solubility-Photovoltaic Performance Relationship in the Design of Novel Fullerene Derivatives for Bulk Heterojunction Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Pavel A. Troshin Abstract The preparation of 27 different derivatives of C60 and C70 fullerenes possessing various aryl (heteroaryl) and/or alkyl groups that are appended to the fullerene cage via a cyclopropane moiety and their use in bulk heterojunction polymer solar cells is reported. It is shown that even slight variations in the molecular structure of a compound can cause a significant change in its physical properties, in particular its solubility in organic solvents. Furthermore, the solubility of a fullerene derivative strongly affects the morphology of its composite with poly(3-hexylthiophene), which is commonly used as active material in bulk heterojunction organic solar cells. As a consequence, the solar cell parameters strongly depend on the structure and the properties of the fullerene-based material. The power conversion efficiencies for solar cells comprising these fullerene derivatives range from negligibly low (0.02%) to considerably high (4.1%) values. The analysis of extensive sets of experimental data reveals a general dependence of all solar cell parameters on the solubility of the fullerene derivative used as acceptor component in the photoactive layer of an organic solar cell. It is concluded that the best material combinations are those where donor and acceptor components are of similar and sufficiently high solubility in the solvent used for the deposition of the active layer. [source] An Evaluation of Physicochemical Treatment Technologies for Water Contaminated with MTBEGROUND WATER MONITORING & REMEDIATION, Issue 4 2000Arturo A. Keller Treatment of methyl tertiary-butyl ether (MTBE) from contaminated surface and ground water supplies presents specific challenges due to the physicochemical properties of MTBE that depend strongly on its hydrophilic nature, and translate into a high solubility in water, and low Henry's constant and low affinity for common adsorbents. We evaluate four treatment technologies-air stripping, granular activated carbon (GAC), hydrophobic hollow fiber membranes, and advanced oxidation processes (AOP)-using ozone or ozone/hydrogen peroxide. Experimental work was carried out to generate parameter values necessary for the design of these processes. Ten different flow rates/concentration combinations were evaluated in our designs to cover the range from high flow rate/low concentration typical of surface water and ground water drinking water supplies to low flow rate/high concentration typical of ground water remediation sites. For all cases, the processes were designed to produce effluent water of 5 ,g/L or less. Capital costs and operation and maintenance costs were determined at the feasibility level by using standard engineering estimating practices. Air stripping is the lowest cost technology for high flow rales (100 to 1000 gpm) if no air treatment is required. Hollow fiber membranes are the lowest cost technology for flow rates of 10 to 100 gpm if no air treatment is required, which is typical at these low flow rates. GAC will be most costeffective at all flow rates if air treatment is required and the influent water has low levels of other organic compounds. AOP using ozone or ozone/hydrogen peroxide is in all cases more expensive than the alternative technologies, and there are sufficient uncertainties at this point with respect to byproducts of AOP to warrant further study of this technology. The cost of treating MTBE-contaminated water for conventional technologies such as air stripping and GAC is 40% to 80% higher than treating water contaminated only with other hydrocarbons such as benzene. [source] THE DEGRADATION OF CHlTOSAN WITH THE AID OF LIPASE FROM RHIZOPUS JAPONICUS FOR THE PRODUCTION OF SOLUBLE CHlTOSANJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2001SEUNG S. SHIN ABSTRACT Lipase from Rhizopus japonicus degraded chitosan resulting in soluble chitosan hydrolysates with molecular weight of about 30,50 kDa as shown by size exclusion chromatography. Optimal temperature for the hydrolysis of chitosan was 40C. The chitosan degradation products were fractionated stepwise according to their molecular weights by ultrafiltration with the filtration range of over 0.1 ,m, 0. l ,m to 30 kDa, 30 kDa to 10 kDa, 10 to 3 kDa, and 3 to 0.2 kDa. These fractions exhibited molecular weights of 50, 41, 41, 35, and 30 kDa, respectively. The molecular weights did not coincide with the pore size of filter membranes. Chitosan hydrolysate exhibited almost the same structural composition in IR spectra as chitosan flakes, except the peak of 1550 nm,1 that appeared to be the COO residue shifted from sodium acetate buffer to amine residue of chitosan. All fractions showed high solubility at neutral pH. The chitosan hydrolysates exhibiting molecular weights between 30 and 41 kDa were considered to be most suitable as a food additive or functional agent as demonstrated by sensory evaluation. [source] Toward greener separations of rare earths: Bifunctional ionic liquid extractants in biodieselAICHE JOURNAL, Issue 9 2010Yinghui Liu Abstract Ionic liquids (ILs) containing quaternary phosphonium cations and phosphonic acid anions were explored as novel extractants for rare earths (RE) separation. They were considered to be bifunctional ionic liquid extractants (bif-ILEs), since both cations and anions of ILs were involved in the extraction. Trihexyl(tetradecyl)phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104), as a bif-ILE, together with propylene carbonate (PC), dimethyl carbonate (DMC), and soybean oil methyl ester (SBME, biodiesel) as diluents was employed in the extraction of RE(III) from aqueous solutions. Acidified Cyphos IL 104 (HNO3 -Cyphos IL 104) exhibited high solubility in three diluents, and higher extraction efficiency than bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) because of the coextraction of RE(III) by quaternary phosphonium cation and phosphonic acid anion in organic phase. Additionally, this coextraction mechanism could eliminate the loss of IL. The physical properties and miscibility test results indicated that SBME was an excellent solvent for RE(III) extraction. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Plasticization and spraying of poly (DL-lactic acid) using supercritical carbon dioxide: control of particle sizeJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2004Jianyuan Hao Abstract Exposure of poly(DL-lactic acid) (PDLLA), and related polymers, to supercritical CO2 (scCO2) at or below, physiological temperatures leads to very effective plasticization and liquefying of the polymers. The phenomenon arises from the high solubility and interaction of the scCO2 in the polymer. Under these unique conditions, temperature and solvent labile molecules can be mixed efficiently into the liquefied polymer. This liquefied polymer/drug/CO2 mixture can then be sprayed into a collecting chamber, and during this process particles of drug-loaded polymer are formed. This process is very different from rapid expansion and antisolvent based techniques that have been previously reported. In this article, we describe a method of controlling particle size during the spray process by introducing a backpressure of N2 in the collecting chamber. This backpressure dynamically regulates the loss of CO2 from the issuing polymer/CO2 mixture, leading to control over sprayed particle size. In situ observation of the viscosity of the plasticized polymer indicates that a backpressure of 68 bar or greater is necessary to ensure the production of fine particles. The influences of backpressure and saturation temperature on particle size for the sprayed products are discussed in terms of observed PDLLA/CO2 mixture viscosities. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93: 1083,1090, 2004 [source] Main-chain viologen polymers with triflimide counterion exhibiting lyotropic liquid-crystalline properties in polar organic solvents,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2002Pradip K. Bhowmik Abstract The solution-phase behavior of three main-chain viologen polymers, which are composed of isomeric xylyl units and triflimide as a counterion, was studied in methanol, dimethylformamide, acetonitrile, and dimethyl sulfoxide as solvents microscopically under crossed polarizers. Each of them exhibited a lyotropic lamellar phase in both polar protic and aprotic solvents. Their C* for the formation of biphasic solutions (1,5 wt %) and concentrations (20,30 wt %) for the lyotropic solutions in methanol was much lower than those in polar aprotic solvents (20,71 and 60,81 wt %, respectively). Their high solubility, high C* for the formation of biphasic solutions, and high concentrations for the formation of lyotropic solutions in polar aprotic solvents were related to the significant reduction of strong ionic interactions between triflimide and 4,4,-bipyridinium ions in each of these viologen polymers. They were the first examples of viologen polymers that exhibited a lyotropic phase in polar aprotic solvents. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2015,2024, 2002 [source] Mechanisms and Kinetics of the Hydrothermal Oxidation of Bulk Titanium Silicon CarbideJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2010Haibin Zhang Hydrothermal oxidation of bulk Ti3SiC2 in continuous water flow was studied at 500°,700°C under a hydrostatic pressure of 35 MPa. The oxidation was weak at 500°,600°C and accelerated at 700°C due to the formation of cracks in oxides. The kinetics obeyed a linear time-law. Due to the high solubility of silica in hydrothermal water, the resulting oxide layers only consisted of titanium oxides and carbon. Besides general oxidation, two special modes are very likely present in current experiments: (1) preferential hydrothermal oxidation of lattice planes perpendicular to the c -axis inducing cleavage of grains and (2) uneven hydrothermal oxidation related to the occurrence of TiC and SiC impurity inclusions. Nonetheless the resistance against hydrothermal oxidation is remarkably high up to 700°C. [source] Synthesis and Evaluation of Water-Soluble Fluorinated Dendritic Block-Copolymer Nanoparticles as a 19F-MRI Contrast AgentMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 14 2010Michihiro Ogawa Abstract Well-defined water-soluble fluorinated polymer nanoparticles (PNPs) with a high fluorine content and biocompatibility were successfully prepared by living radical polymerization (LRP) of 2,2,3,3-tetrafluoropropyl methacrylate (TFPMA) from the polyamidoamine dendrimer macroinitiator (PAMAM-Br), and successive block polymerization of carboxybetaine monomer (CMB). The obtained core,shell type PNPs (PAMAM- g -PTFPMA- b -PCMB) showed high solubility in water and a sphere-like structure with a diameter in the range of 15,80,nm in water. The short 19F-NMR spin,lattice relaxation time (T1) (<250,ms) of PAMAM- g -PTFPMA- b -PCMB allowed the use of fast repetition time. The spin,spin relaxation time (T2) was evaluated to be as low as 10 ms. 19F-MRI in vitro signals can be detectable even at concentrations lower than 1 µM (particle concentration). These results demonstrate that a new type of 19F-MRI contrast agent can be developed by the molecular design using the dendrimer-initiated LRP method. [source] Synthesis and Properties of Novel Fluorinated Poly(phenylene- co -imide)sMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 3 2007Wenmu Li Abstract A new class of high-performance materials, fluorinated poly(phenylene- co -imide)s, were prepared by Ni(0)-catalytic coupling of 2,5-dichlorobenzophenone with fluorinated dichlorophthalimide. The synthesized copolymers have high molecular weights (,=,5.74,×,104,17.3,×,104 g,·,mol,1), and a combination of desirable properties such as high solubility in common organic solvent, film-forming ability, and excellent mechanical properties. The glass transition temperature (Tgs) of the copolymers was readily tuned to be between 219 and 354,°C via systematic variation of the ratio of the two comonomers. The tough polymer films, obtained by casting from solution, had tensile strength, elongation at break, and tensile modulus values in the range of 66.7,266 MPa, 2.7,13.5%, and 3.13,4.09 GPa, respectively. The oxygen permeability coefficients () and permeability selectivity of oxygen to nitrogen () of these copolymer membranes were in the range of 0.78,3.01 barrer [1 barrer,=,10,10 cm3 (STP) cm/(cm2,·,s,·,cmHg)] and 5.09,6.25, respectively. Consequently, these materials have shown promise as engineering plastics and gas-separation membrane materials. [source] Blue Emission of a Soluble Poly(p -phenylene) with a Cross-Conjugated Bisimidazole-Based ChromophoreMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 1 2007Frank Dierschke Abstract A novel poly(p -phenylene) (6) has been synthesized by a cruciform combination of a polyphenylene backbone with 2,2,-(p -phenylene)-bis(4,5-diphenylimidazole) (5) as an additional, orthogonal chromophore. Polymer 6 showed in solution and in the solid state, a blue-green emission, which is obviously arising from the second bisimidazole-based chromophore. UV-Vis spectroscopy, and cyclic voltammetry revealed that the optical and electronic properties of 6 were fully determined by the incorporated 2,2,-(1,4-phenylene)bisimidazole structure. The bisimidazole unit led to high solubility and, despite the steric demand of the substituents, at the same time to the blue-green emission of the poly(p -phenylene) (6). In addition, the oxidation of 6 with potassium ferricyanide yielded a low bandgap polymer with a quinoid-type structure and a bandgap of 1.6 eV. [source] Advancing the Solid State Properties of Metallo-Supramolecular Materials: Poly(, -caprolactone) Modified , -Conjugated Bis(terpyridine)s and their Zn(II) Based Metallo-PolymersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2008Andreas Winter Abstract A set of rigid , -conjugated bis(terpyridine) macroligands with poly(, -caprolactone) (pCL) on their side chains was synthesized and investigated. The introduced pCL chains gave rise to enhanced processability and film-forming properties of the materials. Blue photoluminescence with high quantum yields was observed in dilute solution and in the solid state, indicating that intermolecular aggregation of the , -conjugated systems was effectively suppressed. The macroligands were further used for coordination with zinc(II) ions leading to new metallo-polymers with high solubility, improved film-forming behavior and promising photophysical properties with respect to potential OLED applications. [source] New organosoluble polyimides with low dielectric constants derived from bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl] diphenylmethyleneMACROMOLECULAR SYMPOSIA, Issue 1 2003Der-Jang Liaw Abstract A new kink diamine with trifluoromethyl group on either side, bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl]diphenylmethane(BTFAPDM), was reacted with various aromatic dianhydrides to prepare polyimides via poly (amic acid) precursors followed by thermal or chemical imidization. Polyimides were prepared using 3,3,, 4,4,-biphenyltetracarboxylic dianhydride(1), 4,4,-oxydiphthalic anhydride(2), 3,3,,4,4,-benzophenonetetracarboxylic dianhydride (3), 4,4,-sulfonyldiphthalic anhydride(4), and 4,4,-hexafluoroisopropylidene-diphathalic anhydride(5). The fluoro-polyimides exhibited low dielectric constants between 2.46 and 2.98, light color, and excellent high solubility. They exhibited glass transition temperatures between 227 and 253°C, and possessed a coefficient of thermal expansion (CTE) of 60-88 ppm/°C. Polymers PI-2, PI-3, PI-4, PI-5 showed excellent solubility in the organic solvents: N -methyl-2-pyrrolidinone (NMP), N,N -dimethylacetamide (DMAc), N,N -dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridkie and tetrahydrofuran (THF). Inherent viscosity of the polyimides were found to range between 0.58 and 0.72 dLg-1. Thermogravimetric analysis of the polyimides revealed a high thermal stability decomposition temperature in excess of 500°C in nitrogen. Temperature at 10 % weight loss was found to be in the range 506-563°C and 498-557°C in nitrogen and air, respectively. The polyimide films had a tensile strength in the range 75-87 MPa; tensile modulus, 1.5-2.2 GPa; and elongation at break, 6-7%. [source] Corrosion control of phenylthiourea polymers on aluminium in alkaline mediumMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 1 2008B. J. Vasanthi Simple phenylthiourea compounds are known for their high solubility in alkaline medium and for good corrosion control. The monomer N -(4-hydroxy-3-methoxybenzal)- N,-(4,-hydroxyphenyl) thiourea was condensed with pimeloylchloride and azeloylchloride through inter-facial polycondensation method to synthesize the polymers. The polymers were dissolved in 2 N sodium hydroxide and their corrosion controlling efficiency on aluminium was studied through AC impedance and potentiodynamic polarization methods. [source] Size and Aggregation of Corticosteroids Used for Epidural InjectionsPAIN MEDICINE, Issue 2 2008Richard Derby MD ABSTRACT Objective., The purpose of this study was to document particulate size in commonly used corticosteroid preparations. Inadvertent injection of particulate corticosteroids into a vertebral or foraminal artery can cause brain and spinal cord embolic infarcts and the size of the particles could be directly related to the chance that a clinically significant infarct would occur. One might assume that corticosteroids with particles significantly smaller than red blood cells might be safer. Design., The following four types of corticosteroid preparations were used in various solutions and evaluated under light microscopy: dexamethasone sodium phosphate injection, triamcinolone acetonide injectable suspension, betamethasone sodium phosphate and betamethasone acetate injectable suspension, and methylprednisolone acetate injectable suspension. Results., Dexamethasone sodium phosphate particle size was approximately 10 times smaller than red blood cells and the particles did not appear to aggregate; even mixed with 1% lidocaine HCl solution and with contrast dye, the size of the particles were unchanged. Triamcinolone acetonide and betamethasone sodium phosphate showed variable sizes; some particles were larger than red blood cells, and aggregation of particles was evident. Methylprednisolone acetate showed uniformity in size and the majority were smaller than red blood cells which were not aggregated, but the particles were densely packed. Conclusions., Compared with the particulate steroid solutions, dexamethasone sodium phosphate had particles that were significantly smaller than red blood cells, had the least tendency to aggregation, and had the lowest density. These characteristics should significantly reduce the risk of embolic infarcts or prevent them from occurring after intra-arterial injection. Until shown otherwise in clinical studies, interventionalists might consider using dexamethasone or another corticosteroid preparation with similar high solubility and negligible particle size when performing epidural injections. [source] Synthesis and properties of new aromatic polyimides based on 2,2,-dibromo-4,4,,5,5,-benzophenone tetracarboxylic dianhydridePOLYMER INTERNATIONAL, Issue 8 2004Ahmad Banihashemi Abstract New polyimides with enhanced thermal stability and high solubility were synthesized in common organic solvents from a new dianhydride, 2,2,-dibromo-4,4,,5,5,-benzophenone tetracarboxylic dianhydride (DBBTDA). DBBTDA was used as monomer to synthesize polyimides by using various aromatic diamines. The polymers were characterized by IR and NMR spectroscopy and elemental analysis. These polyimides had good inherent viscosities in N -methyl-2-pyrrolidinone (NMP) and also high solubility and excellent thermo-oxidative stability, with 5 % weight loss in the range 433 to 597 °C. Copyright © 2004 Society of Chemical Industry [source] THE EFFECT OF SALTS ON THERMAL AND HYDRIC DILATATION OF POROUS BUILDING STONE*ARCHAEOMETRY, Issue 3 2009M. AL-NADDAF Fifteen desalinated sandstone drill core samples from Umm Ishrin Sandstone Formation in Petra (Cambrian age) were used for this study. The samples were mineralogically analysed using X-ray diffraction and their physical properties were also determined. Samples with similar physical properties and mineralogical composition were taken for further experimental work. After desalination, thermal and hydric dilatation coefficients were measured, then three types of salts (NaCl, KCl and Na2SO4·10H2O), which have high solubility and consequently are the most dangerous to building stone (and are also detected in the sandstone monuments in Petra), were introduced into the samples and their contents were calculated. The results show that salt crystallization in the pores of building stones can increase their thermal dilatation and decrease their hydric dilatation to varying extents, depending on the nature of the salt. The average increase in the thermal dilatation coefficient per unit mass of salt is the lowest for the Na2SO4·10H2O-salted samples with a value of 5.3%, while the NaCl-salted samples have the highest value with 7.8% per salt mass. The average percentage of the decrease of the hydric dilatation coefficient is 1061% for Na2SO4·10H2O-salted samples per mass of salt content; the NaCl-salted samples have a value of 1510% per mass of salt content, and the KCl-salted samples almost the same value. For the salt-free samples, it was found that in climatic conditions with a high temperature range, the deterioration of sandstone due to temperature fluctuation is more effective than that caused by change in the moisture content, while samples with high salt content suffer more from hydric dilatation. [source] Perfluorocarbon-Based Oxygen Carriers: Review of Products and TrialsARTIFICIAL ORGANS, Issue 8 2010Camila Irene Castro Abstract A viable blood substitute is still of great necessity throughout the world. Perfluorocarbon-based oxygen carriers (PFCOCs) are emulsions that take advantage of the high solubility of respiratory gases in perfluorocarbons (PFCs). Despite attractive characteristics, no PFCOC is currently approved for clinical uses. Some PFCOCs have failed due to secondary effects of the surfactants employed, like Fluosol DA, whereas others to adverse cerebrovascular effects on cardiopulmonary bypass, such as Oxygent. Further in-depth, rigorous work is needed to overcome the annotated failures and to obtain a safe PFCOC approved for human use. The aim of this study is to review in detail the most-used PFCOCs, their formulation, and preclinical and clinical trials, and to reflect upon causes of failure and strategies to overcome such failures. [source] Recombinant murine growth hormone from E. coli inclusion bodies: Expression, high-pressure solubilization and refolding, and characterization of activity and structureBIOTECHNOLOGY PROGRESS, Issue 3 2010Amber Haynes Fradkin Abstract We expressed recombinant murine growth hormone (rmGH) in E. coli as a cost-effective way to produce large quantities (gram scale) of the protein for use in murine studies of immunogenicity to therapeutic proteins. High hydrostatic pressure was used to achieve high solubility and high refolding yields of rmGH protein produced in E. coli inclusion bodies. A two-step column purification protocol was used to produce 99% pure monomeric rmGH. Secondary and tertiary structures of purified rmGH were investigated using circular dichroism and 2D-UV spectroscopy. The purified rmGH produced was found to be biologically active in hypophysectomized rats. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] DJ-927, a novel oral taxane, overcomes P-glycoprotein-mediated multidrug resistance in vitro and in vivoCANCER SCIENCE, Issue 5 2003Motoko Shionoya DJ-927 is a novel taxane, which was selected for high solubility, non-neurotoxicity, oral bioavailability, and potent antitumor activity. In this study, we compared the in vitro and in vivo efficacy of DJ-927 with those of paclitaxel and docetaxel. DJ-927 exhibited stronger cytotoxicity than paclitaxel and docetaxel in various tumor cell lines, especially against P-glycoprotein (P-gp)-expressing cells. The cytotoxicity of DJ-927, unlike those of other taxanes, was not affected by the P-gp expression level in tumor cells, or by the co-presence of a P-gp modulator. When intracellular accumulation of the three compounds was compared, intracellular amounts of DJ-927 were much higher than those of paclitaxel or docetaxel, particularly in P-gp-positive cells. In vivo, DJ-927 showed potent antitumor effects against two human solid tumors in male BALB/c- nu/nu mice, and yielded significant life-prolongation in a murine liver metastasis model with male C57BL/6 mice, in which neither paclitaxel nor docetaxel was effective. The results demonstrate the superior efficacy of orally administered DJ-927 over intravenously administered paclitaxel or docetaxel against P-gp-expressing tumors, probably due to higher intracellular accumulation. A phase I clinical trials of DJ-927 is currently ongoing in the US. (Cancer Sci 2003; 94: 459,466) [source] Red-Emitting Rhodamine Dyes for Fluorescence Microscopy and NanoscopyCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2010Kirill Kolmakov Dr. Abstract Fluorescent markers emitting in the red are extremely valuable in biological microscopy since they minimize cellular autofluorescence and increase flexibility in multicolor experiments. Novel rhodamine dyes excitable with 630,nm laser light and emitting at around 660,nm have been developed. The new rhodamines are very photostable and have high fluorescence quantum yields of up to 80,%, long excited state lifetimes of 3.4,ns, and comparatively low intersystem-crossing rates. They perform very well both in conventional and in subdiffraction-resolution microscopy such as STED (stimulated emission depletion) and GSDIM (ground-state depletion with individual molecular return), as well as in single-molecule-based experiments such as fluorescence correlation spectroscopy (FCS). Syntheses of lipophilic and hydrophilic derivatives starting from the same chromophore-containing scaffold are described. Introduction of two sulfo groups provides high solubility in water and a considerable rise in fluorescence quantum yield. The attachment of amino or thiol reactive groups allows the dyes to be used as fluorescent markers in biology. Dyes deuterated at certain positions have narrow and symmetrical molecular mass distribution patterns, and are proposed as new tags in MS or LC-MS for identification and quantification of various substance classes (e.g., amines and thiols) in complex mixtures. High-resolution GSDIM images and live-cell STED-FCS experiments on labeled microtubules and lipids prove the versatility of the novel probes for modern fluorescence microscopy and nanoscopy. [source] Catalytic Properties of Nanoscale Iron-Doped Zirconia Solid-Solution Aerogels,CHEMPHYSCHEM, Issue 7 2008Lifang Chen Abstract Nanoscale iron-doped zirconia solid-solution aerogels are prepared via a simple ethanol thermal route using zirconyl nitrate and iron nitrate as starting materials, followed by a supercritical fluid drying process. Structural characteristics are investigated by means of powder X-ray diffraction (XRD), thermal analyses (TG/DTA), N2 adsorption measurements and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results show that the resulting iron-doped solid solutions are metastable tetragonal zirconia which exhibit excellent dispersibility and high solubility of iron oxide. Further, when the Fe:(Fe+Zr) ratio x is lower than 0.10, all of the Fe3+ ions can be incorporated into ZrO2 by substituting Zr4+ to form Zr1,xFexOy solid solutions. Moreover, for the first time, an additional hydroxyl group band that is not present in pure ZrO2 is observed by DRIFTS for the Zr(Fe)O2 solid solution. This is direct evidence of Fe3+ ions incorporated into ZrO2. These Zr1,xFexOy solid solutions are excellent catalysts for the solvent-free aerobic oxidation of n -hexadecane using air as the oxidant under ambient conditions. The Zr0.8Fe0.2Oy solid-solution catalyst demonstrates the best catalytic properties, with the conversion of n -hexadecane reaching 36.2,% with 48,% selectivity for ketones and 24,% selectivity for alcohols and it can be recycled five times without significant loss of activity. [source] | ||||||||||||||||||||||