Homogeneous surface coating of bolts, nuts, and screws by barrel-sputtering technique

Our newly developed “barrel-sputtering” technique has been employed for the surface coating of solid substrates with complex shapes such as bolts, nuts, and screws. The entire surface of the iron bolts and nuts including the flank and the root in the thread is homogeneously coated with the Au film. SEM measurements reveals that the surface of the Au film is very smooth. In the SEM measurements of the cross-sectional area, it is found that the Au film possess uniform thickness without any significant defects and/or pits. The Au film coating can also be successfully conducted on polycarbonate bolts and small SUS screws. The results provide evidences that the sputter deposition takes place in “three-dimensionally.”     

Comparison of DRAM capacitor dielectric by stored charge andholding time using TQV chart

Dielectric films for DRAM storage capacitors were examined using a TQV chart. This chart enables comparison of performance between different insulating materials with different current-voltage behaviors. It was believed that insulators with higher dielectric constant have larger leakage current, but the results show otherwise. A BaSrTiO₃ film performed best, but the step coverage of the film should be improved. Silicon nitride films are approaching a thickness limitation, but could be effective if the capacitor electrode structure is improved to utilize the good step coverage     

The protective effect of hyperbaric oxygenation on the small intestine in ischemia-reperfusion injury

Hyperbaric oxygenation has been used as the method of treatment in several ischemic diseases, but its effectiveness still remains controversial. The authors investigated the effect of hyperbaric oxygenation on ischemia-reperfusion injury of the small intestine using a rat model. Wistar King A Makino (WKAM) rats were subjected to 120 minutes of superior mesenteric artery occlusion before reperfusion, with 90 minutes of hyperbaric oxygenation (two absolute atmospheric pressure in an experimental hyperbaric chamber) during ischemia in group A and immediately after reperfusion in group B, and no hyperbaric oxygen was provided to group C. Jejunal samples 1.5 cm in length were taken at the end of ischemia in all groups, at 30 minutes after reperfusion in groups A and C, and at 120 minutes after reperfusion in groups B and C, for the measurement of adenine nucleotides (high-performance liquid chromatography method) and for histological examination (hematoxylineosin [HE] staining). The survival rate was significantly higher in group A than in group C. The amount of adenosine triphosphate in the samples was not significantly different among the three groups, whereas the energy charge at the end of ischemia was significantly higher in group A than in group C. Histologically, the damage to the mucosa and the longitudinal muscle layer decreased in group A compared with that observed in groups B and C. These results suggest that hyperbaric oxygenation during ischemia is able to ameliorate ischemia-reperfusion injury in the rat small intestine.     

Temperature measurement under convection and segregation in a vibrated bed of powder: A numerical study

In numerically simulated vibrated beds of powder, we measure temperature under convection by the generalized Einstein's relation. The spatial temperature distribution turns out to be quite uniform except for the boundary layers. In addition to this, temperature remains uniform even if segregation occurs. This suggests the possibility that there exists some thermal equilibrium state even in a vibrated bed of powder. This finding may lead to a unified view of the dynamic steady state of granular matter.     

Computed tomographic findings in peritonsillar abscess and cellulitis

The differentiation of a peritonsillar abscess from peritonsillar cellulitis, although difficult on physical examination, is required in order to determine the appropriate treatment. Peritonsillar cellulitis can be treated with antibiotics alone, while a peritonsillar abscess should be drained. Computed tomography (CT) of the neck is often performed to identify the formation of a deep abscess in the neck, but is rarely used to diagnose peritonsillar infections. We report a patient in whom CT was a useful diagnostic tool for distinguishing peritonsillar abscess from peritonsillar cellulitis.     

Modulation of nanotube formation in apatite single crystal via organic molecule incorporation

Hydroxyapatite materials are potentially useful for biomedical application, especially as vehicles for functional molecules. Structural control of bulk apatite materials, such as in the fabrication of hollow microspheres or porous structures, has been studied for this purpose. However, control of the internal structure of the source apatite crystal itself is still a challenge. Here, we show that small organic molecules incorporated in apatite crystals act as porogens which control the porous structure of apatite single crystal. The presence of amino acid under apatite synthesis conditions leads to firm bindings and encapsulation of the amino acid in apatite single crystals. Amino acid elimination by heating or electron beam irradiation enhances the pore formation in apatite single crystal. Moreover, incorporation of an acidic amino acid in apatite induces peapod like nanotubes in apatite single crystals. This study suggests the potential of using small organics for nano-structural control of apatite single crystals which would be valuable for enhancing drug loadings or modulating material digestion in vivo.     

Role of ComFA in controlling the DNA uptake rate during transformation of competent Bacillus subtilis

The roles of ComFA and ComEC in DNA uptake by competent Bacillus subtilis were analyzed by transformation with DNA in protoplast lysates (LP transformation). Deletion mutants of comFA and comEC and putative Walker A mutants (K152N, K152Q, K152E) of comFA were constructed by fusion polymerase chain reaction. Transformants of comEC mutant with purified DNA and DNA in protoplast lysate were not obtained, which shows a lack of transformation ability and backwards recombination of the mutant. Transformants of the comFA mutant were obtained by LP transformation (1.8 × 10(4) transformants/μg DNA). Low relative efficiency of transformation (RET) of comFA compared to wild type (4.3 × 10(-4)) showed an important role for comFA in DNA uptake. Walker A mutants showed 1.8-19 × 10(-4) RET, suggesting a dependence on ATPase activity for transformation. Co-transformation between short linkages was only detected in comFA mutants. The results demonstrated that ComFA controlled the DNA uptake rate. The interpretation was further supported by analyzing the plasmid used in LP transformation of the comFA mutant. The RET of comFA compared to the wild type was 2.7 × 10(-2), 60-fold higher than that with chromosomal DNA (4.3 × 10(-4)). Following addition of DNA into comFA culture, transformants were obtained after 15 min, with the number of transformants increasing over time. The kinetics strongly suggested that in comFA mutants, formation of another DNA uptake complex without ComFA would be a lengthy process.     

Induced albumin secretion from HepG2 spheroids prepared using poly(ethylene glycol) derivative with oleyl groups

We developed a poly(ethylene glycol) (PEG) derivative with oleyl groups, so-called “cell adhesive”, for the promotion of human hepatocellular carcinoma HepG2 cell spheroids. Our approach was based on crosslinking of the cell membrane with a cell adhesive via a hydrophobic interaction. A cell adhesive, PEG derivative with hydrophobic oleyl groups at both ends was synthesized and characterized. HepG2 spheroids formed when the adhesive was added to cell suspensions. The size of the spheroids increased with time in culture. In addition, Ammonia elimination of HepG2 spheroid with cell adhesive was 3.4 times higher than that without cell adhesive. Furthermore, albumin secretion from HeG2 spheroids grown with the cell adhesive for 7 days was 3.3 times that from HepG2 spheroids grown without cell adhesive. Fluorescence microscopy showed greater albumin staining in spheroids grown with cell adhesive compared with spheroids grown without adhesive. This cell adhesive may be useful not only for single type of cells but also for multi types of cells to form artificial organs. This cell adhesive will be a key material for liver tissue engineering when it will apply to primary hepatocytes.     

Mid-diastolic potential is related to the reentrant circuit in a patient with verapamil-sensitive idiopathic left ventricular tachycardia

We report a case of verapamil-sensitive idiopathic ventricular tachycardia in which a mid-diastolic potential (MDP) 45 msec preceding the Purkinje potential (P potential) was recorded. Pacing during the tachycardia caused concealed entrainment, and the stimulus-QRS interval was equal to the P potential-QRS interval. The interval between the last pacing stimulus and the next P potential (postpacing interval) was longer than the ventricular tachycardia cycle length, but the MDP was orthodromically activated. These findings suggest that the MDP was on the reentrant circuit and the P potential was not on the reentrant circuit, but a bystander.     

Fidelity levels of DNA polymerases in tumorigenic state cells and serially transplantable tumor cells

The crystal structure of a calcium-bound form of bovine annexin VI has been determined with X-ray diffraction data to 2.9 A by molecular replacement. Six Ca2+ ions were found, five in AB loops, one in a DE loop. Two loops (II-AB, which binds calcium, and V-AB, which does not) have conformations that differ significantly from those in calcium-free, human recombinant annexin VI. There are only small differences between the calci- and the apo-annexin VI in the rest of the molecule. Calcium by itself does not promote a major conformational change.