Studies on microcapsules

Summary The permeability of polyphthalamide microcapsules to various electrolytes was studied. The permeability constants were found to be of the order of 10^–8 cm/sec and almost temperature-independent. The surprisingly low permeation rate was ascribed to the formation of a stable diffusion layer of the electrolytes in the interior of microcapsules. The insignificant temperature effect was interpreted as being due to the presence of adsorbed Tween 20 molecules on the microcapsule membrane.

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Zusammenfassung Es wurde die Durchlässigkeit von Polyphthalamidmikrokapseln für verschiedene Elektrolyten untersucht. Die Durchlässigkeitskonstanten liegen in der Größenordnung von 10^–8 cm/sec und sind von der Temperatur fast unabhängig. Die unerwartet niedrige Permeationsgeschwindigkeit wurde der Bildung einer stabilen Diffusionsschicht des Elektrolyten innerhalb der Mikrokapseln zugeschrieben. Der geringe Temperatureffekt wurde auf die Existenz der an die Mikrokapselmembranen adsorbierten Moleküle von Tween 20 zurückgeführt.

     

Chemical synthesis of phosphorylated fundamental structure of lipid a

1-α-Monophosphate ($\text{2}$), 4′-monophosphate ($\text{3}$), and 1-α, 4′-diphosphate ($\text{4}$) of 6-0-(2-deoxy-2-tetradecanoylamino-6-0-tetradecanoyl-β-D-glucopyranosyl) -2-deoxy-2-tetradecanoylamino-3, 4-di -0-tetradecanoyl-D-glucopyranose were prepared in order to elucidate the role of phosphate moieties in endotoxic activity of lipid A.     

Clinical comparison of 99mTc-diethylenetriaminepentaacetic acid-human serum albumin (99mTc-HSA-D) and 99mTc-human serum albumin (99mTc-HSA) for cardiac blood pool imaging

99mTc-HSA-D has been developed as a new blood pool scanning agent. Clinical comparison of 99mTc-HSA-D and 99mTc-HSA was made in 16 cases. The activity concentration of 99mTc in blood was measured during 2 hours after the injection in five cases. 99mTc-HSA-D showed higher concentration compared to 99mTc-HSA with the passage of time. Quantitative analysis of contrast between left ventricle and septum was performed on end diastolic frames of gated images 10 minutes after the injection. There was no obvious difference between 99mTc-HSA-D and 99mTc-HSA. The subjective comparison of detectability of lesions between the two agents was performed on three directional gated images. 99mTc-HSA-D was superior to 99mTc-HSA, because the images of the latter deteriorated with the passage of time. On anterior view images 1 hour after the injection, left ventricle/lung and abdominal aorta/background count ratios were greater for 99mTc-HSA-D in many cases. There was no obvious difference in liver/background and kidney/background count ratios between the two agents. Urinary excretion of 99mTc was considerably lesser for 99mTc-HSA-D. The results indicated that 99mTc-HSA-D was superior to 99mTc-HSA for cardiac blood pool imaging.     

Synthesis and reactions of some 6-aryl and 2,6-diaryl-4-(4′-antipyrinyl)-2,3,4,5-tetrahydropyridazin-3-ones and screening for their antibacterial activities

Some new pyridazinone derivatives(3) were synthesized through addition of antipyrin to β-aroylacrylic acids (1) followed by cyclization of the adducts. Reactions of 3 with ethyl bromoacetate, benzenesulfonyl chloride, benzoyl chloride and POCl₃ give N-substituted products and monochlorosubstituted pyridazines (4), respectively. The reactions of the latter with thiourea give unexpected dithio-derivatives (5), which react with phenylhydrazine to give pyrazolopyridazino pyridazine derivatives (6). Reactions of 2 with NH₂OH in ethanol and pyridine afford oxime and oxazinone derivatives 7 and 8, respectively. The antibacterial activities of several compounds were screened.     

Growth of giant two-dimensional crystal of protein molecules from a three-phase contact line

A novel method to fabricate a two-dimensional (2D) crystal of protein molecules has been developed. The method enables us to control both the position of nucleation and the direction of the crystal growth. The crystal obtained using a protein molecule, ferritin, was found to be composed of a number of densely packed single crystal domains with an unprecedentedly large size of approximately 100 microm(2). This method also reveals characteristic behavior of the spatiotemporal evolution of the crystal; for example, "fusion" of the crystal domains, which is never observed in an ordinary crystal composed of atoms or ions, was demonstrated. Our approach could have potential in fabricating extraordinarily large and highly ordered nanoparticle arrays of organic or inorganic materials.     

Drug Molecular Immobilization and Photofunctionalization of Calcium Phosphates for Exploring Theranostic Functions

Theranostics (bifunction of therapeutics and diagnostics) has attracted increasing attention due to its efficiency that can reduce the physical and financial burden on patients. One of the promising materials for theranostics is calcium phosphate (CP) and it is biocompatible and can be functionalized not only with drug molecules but also with rare earth ions to show photoluminescence that is necessary for the diagnostic purpose. Such the CP-based hybrids are formed in vivo by interacting between functional groups of organic molecules and inorganic ions. It is of great importance to elucidate the interaction of CP with the photofunctional species and the drug molecules to clarify the relationship between the existing state and function. Well-designed photofunctional CPs will contribute to biomedical fields as highly-functional ormultifunctional theranostic materials at the nanoscales. In this review, we describe the hybridization between CPs and heterogeneous species, mainly focusing on europium(III) ion and methylene blue molecule as the representative photofunctional species for theranostics applications.     

Construction of regulated nanospace around a porphyrin core

A series of 1,3,5-phenylene-based rigid dendritic porphyrins were synthesized by Suzuki coupling between a porphyrin core and dendron units. The intramolecular energy transfer was studied by absorption and fluorescence spectroscopies. The encapsulation of the porphyrin core within the 1,3,5-phenylene dendron units was found to provide highly efficient energy transfer from the dendron units to the porphyrin core. The dendritic wedge structure affected the energy transfer efficiency. The 1,3,5-phenylene-based rigid dendron units act as highly efficient light-harvesting antennae. These dendritic porphyrins have also been examined as C(60) hosts and substrate-selective oxidation catalysts. The attachment of the second generation of 1,3,5-phenylene-based dendron units with the porphyrin core enabled a stable inclusion of C(60) in toluene. Furthermore, the size and shape of the nanospace in the rigid dendritic porphyrins were found to affect the selectivity of substrates in the catalytic olefin oxidations.     

High-yield synthesis of 14C labeled alicyclic amino acids with high specific radioactivity using potassium (14C) cyanide

In order to study the tumor specificity of synthetic nonmetabolizing amino acids, 10 different 14C labeled alicyclic amino acids (3a-3j) were synthesized in high yield and with high specific radioactivity. Carbon-14 labeled alicyclic hydantoins (2a-2j) were synthesized from a small amount of radioactive potassium [14C] cyanide and corresponding ketones (1a-1j). Th 14C hydantoins (2a-2j) thus obtained were hydrolyzed without isolation to give 14C labeled alicyclic amino acids (3a-3j). The overall radiochemical yields of the amino acids (3a-3j) from potassium [14C] cyanide were 55.6-93.2% with radiochemical purity more than 99%. Specific activities of these 14C labeled compounds (3a-3j) were 209- 250 MBq/mmol (5.66-6.75 mCi/mmol). When non-radioactive potassium cyanide was not added as a carrier, 1-aminocyclopentane[14C]-carboxylic acid (3b) and 1-aminocyclooctane[14C]carboxylic acid (3e) were synthesized in the yield of 64.9 and 19.0% respectively with the specific activity exceed more than 1.85 GBq/mmol (50mCi/mmol).     

Highly effective and reversible control of the rocking rates of rotaxanes by changes to the size of stimulus-responsive ring components

We have designed and synthesized rotaxanes whose rates of rocking motion (pendular motion) were switched reversibly through changes to the size of the ring component in response to external stimuli. The ring molecules of the rotaxanes incorporate a metaphenylene unit, which swings like a pendulum, and a dianthrylethane unit, which undergoes reversible isomerization in response to photo- and thermal stimuli and changes the size of the ring component. The rocking rates were estimated quantitatively by variable-temperature (VT) NMR spectroscopy and saturation transfer experiments, which revealed substantial changes in the rates between the open and closed forms, particularly in the case of rotaxanes with an isopropoxy group attached to a phenylene unit.     

基于2,5-噻吩二甲酸的钙(Ⅱ)和钡(Ⅱ)配位聚合物的合成、晶体结构及性质

在溶剂热条件下,合成了2个碱土金属配位聚合物[Ca (tdc)(DMF)₂]_n(1)和[Ba (tdc)]_n(2)(H₂tdc=2,5-噻吩二甲酸),分别用元素分析、红外光谱、X射线单晶衍射、粉末衍射、热重分析和荧光光谱对它们进行了表征。结构分析表明,配合物1具有4,4连接的二维层状结构,拓扑符号为(4⁴·6²),而配合物2呈现三维网络结构。固体荧光测试表明配合物1比配合物2具有更显著的荧光性能。