Fabrication of CaCO3-Coated Vesicles by Biomineralization and Their Application as Carriers of Drug Delivery Systems

We fabricated CaCO₃-coated vesicles as drug carriers that release their cargo under a weakly acidic condition. We designed and synthesized a peptide lipid containing the Val-His-Val-Glu-Val-Ser sequence as the hydrophilic part, and with two palmitoyl groups at the N-terminal as the anchor groups of the lipid bilayer membrane. Vesicles embedded with the peptide lipids were prepared. The CaCO₃ coating of the vesicle surface was performed by the mineralization induced by the embedded peptide lipid. The peptide lipid produced the mineral source, CO₃²⁻, for CaCO₃ mineralization through the hydrolysis of urea. We investigated the structure of the obtained CaCO₃-coated vesicles using transmission electron microscopy (TEM). The vesicles retained the spherical shapes, even in vacuo. Furthermore, the vesicles had inner spaces that acted as the drug cargo, as observed by the TEM tomographic analysis. The thickness of the CaCO₃ shell was estimated as ca. 20 nm. CaCO₃-coated vesicles containing hydrophobic or hydrophilic drugs were prepared, and the drug release properties were examined under various pH conditions. The mineralized CaCO₃ shell of the vesicle surface was dissolved under a weakly acidic condition, pH 6.0, such as in the neighborhood of cancer tissues. The degradation of the CaCO₃ shell induced an effective release of the drugs. Such behavior suggests potential of the CaCO₃-coated vesicles as carriers for cancer therapies.     

二氧化碳地中隔离技术及其岩石力学问题

寻求经济又安全的强有力减排技术关系到日本政府能否履行在京都议定书中所作的承诺。二氧化碳是主要的温室气体，二氧化碳地中隔离是把从集中排放源分离得到的二氧化碳注入地下深处具有适当封闭条件的地层中隔离起来，即把二氧化碳归还原处——地球深部。介绍了二氧化碳地中隔离的概念及国际动态，并基于隔离容量、机理、安全性及成本分析，论述其可行性。     

Detection of serum p53 antibodies in patients with esophageal squamous cell carcinoma: correlation with clinicopathologic features and tumor markers

The significance of serum p53-Abs in patients with esophageal squamous cell carcinoma was determined. Examination of clinicopathological features and assessment of tumor marker sensitivities of carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC-Ag) and CYFRA21-1 were performed. Thirty-three (58%) of 57 patients were positive for serum p53-Abs, however, no relation with cancer progression existed. Fourteen of the 33 sero-positive patients revealed normal levels of all tumor markers tested. Thus, serum p53-Abs appears to be a useful marker for the detection of esophageal squamous cell carcinoma.     

Evaluation of left atrial thrombus with computed tomography

Left atrial thrombi were evaluated with computed tomography in 23 patients with mitral valvular diseases. In three of the patients, left atrial thrombi were delineated with computed tomography and were confirmed by cardiac surgery or autopsy. The minimum size of the thrombi detected tomographically was 3.5 gm. There were no false-positive or false-negative results with computed tomography in 13 patients who subsequently underwent cardiac surgery. Computed tomography is essentially noninvasive and appears to be one of the best methods to evaluate left atrial thrombus.     

Hydrolysis of nonionic ester surfactants facilitated by potassium β-glycyrrhizinate: Implication of catalytic functions played by the carboxyl groups

Two different types of methyl esters of β-glycyrrhizinate (GK2) have been prepared to delineate the mechanism of the catalytic action of each carboxyl group of GK2 in the hydrolysis of nonionic fatty acid surfactants. In the acidic pH region of less than 4, the hydrolysis is catalyzed by the carboxyl groups of the sugar moiety, while in the close-to-neutral acidic region, the carboxyl group at the hydrophobic triterpenoid end becomes important in catalysis.     

Control of chip flow with guide grooves for continuous chip disposal and chip-pulling turning

This paper presents a new chip control method with guide grooves formed on the rake face to realize continuous chip disposal and chip-pulling turning. Chips are conventionally broken using chip breakers during turning operations for disposal. However, chips of highly ductile materials or thin chips generated in finishing can not be broken easily. In order to prevent the chips from jamming up, the authors propose to continuously guide the chips away from the cutting point. Special tool tips were developed and tested for guiding the chip. Chip controllability and mechanics of the chip-guided cutting are discussed in the present research.