New magnetic fluid developed with natural organic compounds biocompatible.

This work was developed with an aqueous suspension of maghemite nanoparticles and colloidal emulsions with nanoparticles of magnetite. The nanoparticles were synthesized by co-precipitation method. The first was the magnetic emulsion nanoparticles of maghemite dispersed in the aqueous extract obtained from the leaf embauba (Cecropia Obtusifolia), whose tree is native to Central and South America. Thereby achieving the magnetic fluid extract embauba stabilized with ionic buffer solution pH 7.4. A second emulsion was prepared with colloidal magnetite nanoparticles with surfaces previously coated with oleic acid as a means of dispersing and using the oil extracted from in nature seed Andiroba (Carapa Guianensis), tree of the Brazilian Amazon. These new magnetic fluids the nanoparticles were characterized by Photoacoustic spectroscopy (PAS) to determine the coating layer of molecules on the surfaces of nanoparticles. In aqueous ionic magnetic fluid Cecropia Obtusifolia (MFCO) chlorogenic acid contributes to the electron density in the presence of four groups alcohols, a ketone group and a carboxylic group. In magnetic fluid-based oil andiroba MFAD PAS spectra show that oleic acid molecules are tightly linked on the surface of the nanoparticles.

Defect-induced activity enhancement of enzyme-encapsulated metal-organic frameworks revealed in microfluidic gradient mixing synthesis.

Mimicking the cellular environment, metal-organic frameworks (MOFs) are promising for encapsulating enzymes for general applications in environments often unfavorable for native enzymes. Markedly different from previous researches based on bulk solution synthesis, here, we report the synthesis of enzyme-embedded MOFs in a microfluidic laminar flow. The continuously changed concentrations of MOF precursors in the gradient mixing on-chip resulted in structural defects in products. This defect-generating phenomenon enables multimodal pore size distribution in MOFs and therefore allows improved access of substrates to encapsulated enzymes while maintaining the protection to the enzymes. Thus, the as-produced enzyme-MOF composites showed much higher (~one order of magnitude) biological activity than those from conventional bulk solution synthesis. This work suggests that while microfluidic flow synthesis is currently underexplored, it is a promising strategy in producing highly active enzyme-MOF composites.

Liquid-phase synthesis of block copolymers containing sequence-ordered segments.

Monodisperse sequence-defined oligomers have been synthesized in solution in the absence of protecting groups. These structures have been prepared stepwise using two consecutive chemoselective reactions: 1,3-dipolar cycloaddition of terminal alkynes and azides and amidification of carboxylic acids with primary amines. These oligomers were efficiently constructed on either a conventional solid support (commercial Wang resin) or tailor-made soluble polystyrene supports synthesized by atom-transfer radical polymerization. The latter approach was found to be very versatile. Indeed, well-defined soluble macromolecular supports allowed not only the synthesis and cleavage of defined oligomers (i.e., sacrificial support) but also the preparation of noncleavable block copolymers containing sequence-defined segments.

Sol-gel-based solid-phase microextraction and gas chromatography-mass spectrometry determination of dextromethorphan and dextrorphan in human plasma.

A novel solid-phase microextraction (SPME) method was developed for isolation of dextromethorphan (DM) and its main metabolite dextrorphan (DP) from human plasma followed by GC-MS determination. Three different polymers, poly(dimethylsiloxane) (PDMS), poly(ethylenepropyleneglycol) monobutyl ether (Ucon) and polyethylene glycol (PEG) were synthesized as coated fibers using sol-gel methodologies. DP was converted to its acetyl-derivative prior to extraction and subsequent determination. The porosity of coated fibers was examined by SEM technique. Effects of different parameters such as fiber coating type, extraction mode, agitation method, sample volume, extraction time, and desorption condition, were investigated and optimized. The method is rapid, simple, easy and inexpensive and offers high sensitivity and reproducibility. The limits of detection are 0.010 and 0.015 ng/ml for DM and DP, respectively. The precisions for both analytes are below 5% (n=5). The correlation coefficient was satisfactory (r(2)>0.99) for both DM and DP. Linear ranges were obtained from 0.03 ng/ml to 2 microg/ml for DM and from 0.05 ng/ml to 2 microg/ml for DP.

Solid-phase cyclopalladation in S,C,S'-pincer systems: rising alternative for synthesis in solution.

In pursuit of a new and simple approach to complex organometallic systems, the possibility of formation of a palladium-carbon bond in the solid state via direct cyclopalladation has been studied toward several S,C,S'-pincer ligands with thione sulfur donors of different nature. It is found that mixtures of the ligand and PdCl2(NCPh)2 obtained by the manual grinding of reactants in a mortar efficiently undergo solid-phase cyclometalation upon heating in open test tubes without the addition of a solvent to afford the desired pincer-type products in high yields. In the case of the most active bis(thiocarbamoyl) ligand, solid-phase cyclopalladation proceeds even at room temperature. For the challenging bis(thiophosphoryl) derivative, the preformed non-metallated complexes can be successfully used as a starting material to essentially enhance the yield of the desired pincer complex compared to the conventional synthesis in solution. The solid-phase transformation is followed by IR spectroscopy and SEM analysis. The results obtained show that the suggested solid-phase methodology can serve as a powerful alternative to conventional synthesis of pincer complexes in solution.

Analysis of organic gas phase compounds formed by hydrothermal liquefaction of Dried Distillers Grains with Solubles.

This work provides a comprehensive characterization of the gas phase from hydrothermal liquefaction of Dried Distillers Grains with Solubles (DDGS) collected during a 24-h continuous experiment. The gas consisted mainly of CO2, CO, H2, CH4 and C2H6 accounting for 96 v/v% while further analysis by gas chromatography coupled to mass spectrometry (GC-MS) showed additionally 62 compounds of which 54 were tentatively identified. These products included methanethiol, dimethyl sulfide, various olefins and several aromatic compounds. The composition provided clear indication of the steady state of the system. Apart from CO2, olefins were the most abundant compound class and could provide a source of revenue.

"Reactive filtration": use of functionalized porous polymer monoliths as scavengers in solution-phase synthesis.

[reaction: see text] Solid functionalized porous monolithic disks with reactive polymer chains grafted to their inner pore surface have been developed for scavenging excess reagents from reaction mixtures. A poly(chloromethylstyrene-co-divinylbenzene) monolith was cut into disks and activated by graft polymerizing 4-vinyl-2,2-dimethylazlactone to its pore surface. In contrast to the direct copolymerization of reactive monomers, grafting increases the accessibility of the reactive groups. Application of the reactive disks is demonstrated in the scavenging of excess amines from reaction mixtures in different solvents.

Holmium-166-DTPA as a liquid source for endovascular brachytherapy.

Liquid radiation sources with beta emitters have advantages of accurate positioning and uniform dose distribution to the vessel walls to prevent the restenosis of coronary artery. As a liquid radiation source, 166Ho-DTPA was prepared and evaluated its in-vivo pharmacokinetic behavior through animal studies.166Ho-DTPA was prepared by simple mixing the Holmium with DTPA at room temperature. The radiolabelling yield was 100% when the DTPA/Holmium molar ratio was >2. Radiolabelling of 166Ho-DTPA was not dependent on the pH range of 1.7-7.5. High radiochemical stability (>98%) was maintained over a period of 6 hours even with a radioactivity ( approximately 11.1 GBq/12 mg of DTPA) stored at room temperature. Biodistribution of 166Ho-DTPA in rats and gamma camera images in rabbits showed that 166Ho-DTPA was quickly excreted via the urinary system. The average of T(max) and T(1/2) of 166Ho-DTPA in the kidneys of rabbits were 3.71 +/- 1.18 min and 9.15 +/- 3.15 min. 166Ho-DTPA is a potential liquid radiation source for radiation brachytherapy to prevent the restenosis of the coronary artery using a liquid-filled balloon.

Solution-phase synthesis of Aib-containing cyclic hexapeptides.

The 18-membered Aib-containing cyclohexapeptides, cyclo(-Gly-Aib-Aib-Gly-Aib-Phe-) (22), cyclo(-Gly-Aib-Phe(2Me)-Gly-Aib-Aib-) (24a), cyclo(-Gly-Phe(2Me)-Aib-Gly-Aib-Aib-) (24b), and cyclo(-Gly-Phe(2Me)-Aib-Gly-Aib-Phe-) (25), have efficiently been synthesized by solution-phase techniques. The linear precursors 1a-1d were prepared by combining the 'azirine/oxazolone method' for incorporation of alpha,alpha-disubstituted alpha-amino acids (Aib, Phe(2Me)) into the peptide chains by classical peptide coupling methods for segment condensations. Deprotection of the amino and carboxy termini of 1a-1d, followed by cyclization with DEPC as the coupling reagent, gave the above-mentioned cyclic hexapeptides 22, 24a, 24b, and 25 in good yields (26-57%). The solid-state conformations of the linear hexapeptides 1d, 16 and 27, and of the cyclohexapeptides 22 and 25 have been established by X-ray crystallography.

Harmonic ultrasound fields through layered liquid media.

Harmonic field generation through a layered liquid media is studied experimentally and theoretically. Lateral and axial beam profiles of the fundamental to the 4th harmonic component of the field from a focused, 19-mm diameter transducer were measured using a calibrated hydrophone in a water tank. Measurements were performed before and after the insertion of a cylindrical phantom containing vegetable oil. A frequency domain numerical solution to the "KZK" equation was used to calculate the beam profile, taking into account the acoustic properties of the medium and phantom. Effects of nonlinear propagation, diffraction, attenuation, and reflection are include in the calculation. Agreement within 5% was obtained between measurements and theoretical predictions throughout the mid- and far-field of the transducer for both the uniform path and the layered media. Measurements also were carried out using an unfocused transducer as a receiver. The shape of the axial beam profile using this receiver agreed very well with the theoretical prediction using the "KZK" equation, after accounting for phase variations over the finite-sized detector in the calculated field.

The solution synthesis of antisense oligonucleotide-peptide conjugates directly linked via phosphoramide bond by using a fragment coupling approach.

To improve antisense oligonucleotide penetration inside cells, conjugates of oligonucleotides and cell-penetrating peptides, covalently linked through a phosphoramide bond, were prepared by a fragment coupling approach in the liquid phase. Two methods were used for this synthesis, i.e., phosphorylation of a peptide amino group by an oligonucleotide terminal phosphate 1-hydroxybenzotriazole ester in aqueous media or condensation of phosphate and amino groups in presence of triphenylphosphine, 2,2'-dithiopyridine and 4-dimethylaminopyridine in organic media. Several oligonucleotides, including a 18-mer antisense oligodeoxyribonucleotide complementary to an internal coding region of the reporter gene of the green fluorescent protein (GFP) were prepared. Peptides derived from the third helix of the homeodomain of Antennapedia, the influenza envelope hemagglutinin subunit as well as melittin and polymyxin B were used for the conjugates' synthesis. The peptides with various amino acid composition were chosen to confirm that these coupling methods are of a general use.

Synthesis and characterization of phosphorylated galactomannan: the effect of DS on solution conformation and antioxidant activities.

Phosphorylated derivatives of galactomannan from guar gum (GG) with the degree of substitution (DS) of 0.35-0.52 were synthesized using POCl3/pyridine. FT-IR, (13)C NMR and XPS results revealed that phosphorylation had occurred and C-6 substitution was predominant in phosphorylated guar gum (PGG). PGG showed an increase in Mw and more broad molar mass distribution in size exclusion chromatography (SEC) analysis. Higher reaction temperature (above 60 °C) resulted in a higher MW value in PGG. It might be due to the cross-linking of polysaccharide chains by POCl3 via di-ester which was also supported by monosaccharide composition result. Results of M(W) - (S(2))(z)(1/2) showed a decrease in fractal dimension (df) values. DS had greater influence on its conformation in aqueous solution. The introduction of -PO3H2 groups improved significantly the stiffness of the chains due to the electrostatic effect. Furthermore, antioxidant experiments revealed that high DS could enhance the scavenging activities of radicals of PGG in vitro.

Preparation of microfibers from wood/ionic liquid solutions.

Two types of ionic liquids, 1-ethyl-3-methylimidazolim acetate and 1-ethyl-3-methylimidazolium lactate, were employed for the direct processing of pine wood into microfibers. The concentration of 5 wt.% of wood in ionic liquids was rated as the most appropriate for electrospinning. The fibers were electrospun into the collector water bath. The final structure varied from individual microfibers to fiber bundles. It was demonstrated that 1-ethyl-3-methylimidazolium lactate is a powerful solvent and provides the direct transformation of pristine pine wood into the non-wovens.

Acid-catalyzed liquefaction of bagasse in the presence of polyhydric alcohol.

Bagasse was subjected to a liquefaction process with polyethylene glycol/glycerol using sulfuric acid as catalyst. The effects of various liquefaction conditions, such as reaction time, liquefaction temperature, catalyst content, and liquid ratio (liquefaction solvents/bagasse), on the liquefied residue (LR) content and hydroxyl and acid numbers of liquefied products were investigated. The preferred liquefaction condition of bagasse was determined through orthogonal experiments. The results showed that the catalyst content and reaction time have a greater influence than liquid ratio and liquefaction temperature on the percentage of LR. The hydroxyl and acid numbers of the liquefied products were influenced by many factors, including liquefaction temperature, reaction time, acid content, and liquid ratio. The hydroxyl number of liquefied products decreased as the liquefaction reaction progressed, but the acid number of liquefied products increased. Based on the obtained data, the kinetics for liquefaction was modeled using the first-order reaction rate law and the apparent activation energy for the liquefaction of bagasse was estimated to be 38.30 kJ mol(-1).

Working with small molecules: preparing and storing stock solutions and determination of kinetic solubility.

The handling of organic compounds in the laboratory requires the use of organic (co-) solvents to mediate solubility. Advantages and disadvantages of the widely used solvent dimethylsulfoxide (DMSO) are discussed, and guidelines for dissolution and storage of compounds are given. Finally, nephelometry is introduced as a fast method to determine the kinetic solubility of a compound.

Cadmium sulfide quantum dot/chitosan nanocomposites for latent fingermark detection.

The detection of latent fingermarks is a challenging task in forensic science. Here we present work using highly photoluminescent cadmium sulfide (CdS) quantum dots (QDs) encapsulated in an inexpensive biopolymeric chitosan matrix for latent fingermark detection. Cadmium ions were chelated within the chitosan matrix followed by the rapid addition of sodium sulfide to produce a CdS/chitosan nanocomposite. The average QD size was investigated as a function of precursor concentrations using ultra-violet-vis (UV-vis) spectrophotometry and the QDs were imaged with transmission electron microscopy (TEM). Fluorescence spectrophotometry of the QDs at an excitation of 450 nm showed a narrow emission at 531 nm and broad emission between 600 and 850 nm with a maximum at 716 nm. Freshly deposited latent fingermarks deposited on aluminium foil were clearly detected under a Rofin Polilight at 450 nm by dusting with a freeze-dried suspension of the CdS/chitosan nanocomposite and a surfactant, tergitol, giving a so-called quantum dot surfactant (QDS) powder.

Correlation between the band positions of (SrTiO3)1-x.(LaTiO2N)x solid solutions and photocatalytic properties under visible light irradiation.

N-doped SrTiO3 and (SrTiO3)1-x.(LaTiO2N)x samples were prepared by the thermal ammonolysis method. The photocatalytic activities of the samples were investigated in a water suspension system. Aqueous methanol solution (50 mL CH3OH + 220 mL H2O) for H2 evolution and aqueous silver nitrate solution (270 mL, 0.01 mol L(-1)) for O2 evolution were used as sacrificial reagents. The oxynitrides showed photocatalytic activities under visible light irradiation. The maximum rates of photocatalytic hydrogen and oxygen evolution under visible light irradiation (lambda > 420 nm) were 10 and 8 micromol h(-1), respectively. The samples were characterized by X-ray diffractometry, UV-Vis spectrophotometry, Fourier transform infrared spectrometry, and laser Raman spectroscopy. The unit cell edge length of (SrTiO3)1-x.(LaTiO2N)x increased linearly and their band gaps reduced from 3.18 to 2.04 eV with increasing x from 0 to 0.30. Moreover, the calculation results of (SrTiO3)0.75.(LaTiO2N)0.25 by density functional theory suggested that the band gap narrowing of the solid solutions came from the hybridization of N2p and O2p orbital. The band positions of the solid solutions were further investigated by Mott-Schottky and the onset potential method. The results suggested that the conduction band of the solid solution was lowered, which led to decrement of the hydrogen evolution rate.

Common buffers and stock solutions.

This appendix describes the preparation of buffers and reagents used in the manipulation of nucleic acids.

Standardizing chemical peel solution formulations to avoid mishaps. Great fluctuations in actual concentrations of trichloroacetic acid.

BACKGROUND: Chemical peeling using trichloroacetic acid (TCA) is a popular and long utilized procedure in dermatology and cosmetic surgery. OBJECTIVE: To determine the actual concentration of TCA in four disparate methods of preparation of solutions, expressed in the standard pharmaceutical method of weight to volume (wt/vol). METHODS: Method I was wt/vol, method II was weight to weight (wt/wt), method III was grams of TCA added to 100 cc water, and method IV was the usage of saturated TCA, and calling it 100%, then making appropriate dilutions. The amounts of TCA in each solution for methods II, III, and IV were converted, by calculation, to the wt/vol method. RESULTS: The relative concentrations of TCA, ranked by the wt/vol pharmaceutical standard, showed that from strongest to weakest: method IV > method II > method I > method III. CONCLUSIONS: Tremendous variations were found in the relative concentrations of TCA in these solutions. To avoid mishaps and complications, the wt/vol method should be used.

Production and characteristics of an infusible oxygen-carrying fluid based on hemoglobin intramolecularly cross-linked with sebacic acid.

Research on red cell substitutes requires the availability of oxygen-carrying fluids for physiologic experiments. This article describes the procedure for in-house production of such a fluid. It contains a hemoglobin-based oxygen carrier obtained by reacting human hemoglobin with bis-(3,5-dibromosalicyl) sebacate. This reagent produces intramolecular cross-links between the beta 82 lysines and between the alpha 99 lysines, respectively. The oxygen half-saturation pressure (P50) of the fluid is near 34 mm Hg at 37 degrees C, with a Hill's parameter of n = 2.2. The half-time of intravascular retention is near 3.0 hours in the rat and 6.5 hours in the cat. Spectrophotometric analyses of arterial and venous plasma from an infused rat reveal an efficient oxygen delivery to the tissues by the oxygen carrier. Therefore, this new cross-linked human hemoglobin can be produced in quantities sufficient for in vivo evaluation and with an oxygen affinity and cooperativity adequate for oxygen unloading in plasma.