Preparation and medical application of magnetic beads conjugated with bioactive molecules

Ferrite nanobeads were synthesized from an aqueous solution utilizing Fe²⁺ to Fe³⁺ oxidation for use as magnetic carriers in bioscreening, bio-molecular recognition and anti-cancer diagnosis and therapy. The beads had a crystal structure that was intermediate between Fe₃O₄ and γ-Fe₂O₃. Functional biomolecules were strongly conjugated onto the surfaces of the ferrite beads via COOH and SH groups. The addition of ferrite seed crystals (3-8 nm in size) together with a disaccharide enabled the synthesis of monodisperse, spherical ferrite beads with average diameters (d¯) between 50 and 150 nm and relative deviation Δd/d¯=9-16%. Hollow ferrite nano-spheres (d¯=150-450 nm, Δd/d¯≈10%) were prepared using silica spheres as templates, which were dissolved in NaOH solution. Ferrite beads 40 nm in size were encapsulated in polymer spheres of styrene and polymerized glycidyl methacrylate (poly-GMA), 184±9 nm in diameter. They were used for high throughput bioscreening system for affinity purification of target proteins which make specific bindings to anti-cancer drugs, porphyrins, environment hormones, etc.     

Reduction of 1,4-dien-3-one steroids with LiAl2H4 or NaB2H4: stereospecific deuterium-labeling at the c-1alpha position of a 4-en-3-one steroid

Reduction of a double bond at C-1 of 1,4-dien-3-one steroids 7 and 8 with LiAl2H4 in THF or NaB2H4 in MeOH and H2O gave stereospecifically [1alpha-2H]-labeled 4-en-3-one steroids 9 and 10, respectively. When the deuterated solvents, MeO2H and 2H2O, were used for the reaction of steroid 8 with NaB2H4, [1alpha,2xi-2H2]-labeled compound 10 was produced. This indicates that the reaction proceeds through the initial hydride attack at the C-1alpha position, followed by ketonization of the 2-en-3-ol intermediate.     

Characterization of two epimers, 4alpha and 4beta, of a novel podophyllotoxin-4-O-(D)-6-acetylglucopyranoside from Podophyllum hexandrum by LC-ESI-MS-MS

High-performance liquid chromatography (HPLC) with diode array detection interfaced to electrospray ionization (ESI) mass spectrometry (MS) is applied to identify the two epimers of a novel and minor constituent, podophyllotoxin-4-O-(D)-6-acetylglucopyraniside from high-altitude Podophyllum hexandrum for the first time. This is done by matching the structural information from the tandem MS data with the reported lignan markers. The results show that LC-MS-MS is the method of choice for fast detection and detailed chemical analysis of mixtures in the crude extracts of Podophyllum. The method can be employed in the absence of reference standards for the markers and is particularly useful in view of the scarcity of these rare chemical standards.     

Effect of formulated ingredients on rapidly disintegrating oral tablets prepared by the crystalline transition method

The aim of this article was to determine the optimal ingredients for the rapidly disintegrating oral tablets prepared by the crystalline transition method (CT method). The effect of ingredients (diluent, active drug substance and amorphous sugar) on the characteristics of the tablets was investigated. The ingredients were compressed and the resultant tablets were stored under various conditions. The oral disintegration time of the tablet significantly depended on diluents, due to differences in the penetration of a small amount of water in the mouth and the viscous area formed inside the tablet. The oral disintegration time was 10-30 s for tablets with a tensile strength of approximately 1 MPa, when erythritol, mannitol or xylitol was used as the diluent. The increase in the tensile strength of tablets containing highly water-soluble active drug substances during storage was as large as that of tablets without active drug substances, while the increase in the tensile strength of tablets containing low water-soluble active drug substances was small. It was therefore found that highly water-soluble active drug substances were more suitable for the formulation prepared by the CT method than low water-soluble active drug substances. Irrespective of the type of amorphous sugar (amorphous sucrose, lactose or maltose) used, the porosity of tablets with 1 MPa of tensile strength was 30-40%, and their oral disintegration time was 10-20 s. The optimal ingredients for rapidly disintegrating oral tablets with reasonable tensile strength and disintegration time were therefore determined from these results.     

Effect of visual target blurring on accommodation under distance viewing

Purpose

To examine the effect of visual target blurring on accommodation.

Methods

We evaluated the objective refraction values when the visual target (asterisk; 8°) was changed from the state without Gaussian blur (15 s) to the state with Gaussian blur adapted [0(without blur)?→?10, 0?→?50, 0?→?100: 15 s each].

Results

In Gaussian blur 10, when blurring of the target occurred, refraction value did not change significantly. In Gaussian blur 50 and 100, when blurring of the target occurred, the refraction value became significantly myopic.

Conclusion

Blurring of the distant visual target results in intervention of accommodation.

     

Cyclization of electron-deficient cyclopentadienone with 2-alkenyl and 2-alkynylamines via sequential pericyclic reaction pathway.

The pericyclic reactions of 2,5-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone (1a) with both allylic and propargylic amines have been investigated. The reaction proceeded via initial formation of the 1,4 adducts followed by the ene cyclization and/or sequential pericyclic reactions depending upon the structures of the amines. The reaction of 1a with diallylamine (2a) gave the tetracyclic compound (3a). On the other hand, the reaction of 1a with 2-propynylamine (2c) gave exclusively the bicyclic compound (5c). In the reactions with the secondary 2-propynylamines (2d,e), the tetracyclic compounds (3d,e) were exclusively formed. The reactions of 1a with alpha-branched primary 1,1-dialkyl-2-propynylamines (2f,g) gave mixtures of 3- and 5-type compounds. The tetracyclic compounds 3 were formed from the intramolecular [4+2]pi cycloadditions of the [1,5]-sigmatropic rearrangement products of the 1,4 adducts of 1a and 2, followed by the [1,5]-sigmatropic rearrangement of hydrogen and dehydrogenation. The bicyclic compounds 5 were derived from the [2pi+2pi+2sigma] reaction of the 1,4 adducts of 1a and 2. The one-pot multistage sequential pericyclic reactions were discussed on the basis of the X-ray crystallographic structures and the MO calculation data.     

Mixed-Valent Trinuclear CoIII-CoII-CoIII Complex with 1,3-Bis(5-chlorosalicylideneamino)-2-propanol

A mixed-valent trinuclear complex with 1,3-bis(5-chlorosalicylideneamino)-2-propanol (H₃clsalpr) was synthesized, and the crystal structure was determined by the single-crystal X-ray diffraction method at 90 K. The molecule is a trinuclear Co^III-Co^II-Co^III complex with octahedral geometries, having a tetradentate chelate of the Schiff-base ligand, bridging acetate, monodentate acetate coordination to each terminal Co³⁺ ion and four bridging phenoxido-oxygen of two Schiff-base ligands, and two bridging acetate-oxygen atoms for the central Co²⁺ ion. The electronic spectral feature is consistent with the mixed valent Co^III-Co^II-Co^III. Variable-temperature magnetic susceptibility data could be analyzed by consideration of the axial distortion of the central Co²⁺ ion with the parameters Δ = –254 cm⁻¹, λ = –58 cm⁻¹, κ = 0.93, tip = 0.00436 cm³ mol⁻¹, θ = –0.469 K, g_z = 6.90, and g_x = 2.64, in accordance with a large anisotropy. The cyclic voltammogram showed an irreversible reduction wave at approximately −1.2 V·vs. Fc/Fc⁺, assignable to the reduction of the terminal Co³⁺ ions.     

Theoretical study of a new energy extraction scheme of a chemically pumped pulsed iodine laser amplifier

A new energy extraction scheme of a chemically pumped pulsed large-scale iodine laser based on a high-pressure pulsed singlet oxygen generator is proposed. In previous investigations only low-pressure oxygen generators have been considered. Since they require a high iodine density for an efficient amplifier operation, the lifetime of the stored energy is correspondingly small and thus only small-sized iodine amplifiers appear to be technically feasible. We found, however, that when the singlet oxygen is generated at high-pressure, the iodine density required can be considerably reduced so that the lifetime of the stored energy becomes sufficiently long to fill up large amplifier cells. A numerical model is developed and the extractable energy is theoretically estimated. It is shown that 0.2J/1·pass can be extracted when an input pulse of 20 ns duration (FWHM) and 1 J/cm² fluence is fed into the amplifying medium.     

Characterization of DMNB,a detection agent for explosives,by thermal analysis and solid state NMR

The thermal properties of 2,3-dimethyl-2,3-dinitrobutane (DMNB), a detection agent for explosives, have been determined by DSC measurements. Additionally, the results of an NMR study are compared with conclusions arrived at in the literature with regard to the source of two endotherms observed in the DSC. The thermal decomposition of DMNB is characterized by an exotherm with an energy in excess of 3 kJ g^?1, observed in conjunction with a third endotherm resulting from the fusion of DMNB. Arrhenius parameters determined from both variable heating rate and isothermal measurements in the DSC are compared with predicted values assuming various mechanisms for the decomposition process.