Carbon nanotube enables quantum leap in oil recovery

A novel sealing material based on a CNT-rubber composite was developed for use in producing oil from deep, hot reservoirs. Fully dispersed and better bondings are two critical advances that enhance its mechanical properties. Authors solved the critical issues and clarified the mechanism of nano network reinforcement using test data. The resulting sealing solution underwent field tests around the world, and it marks a rare success story for the use of nanotechnology in the oilfield.     

Synchronous Composite Packet Switching-A Switching Architecture for Broadband ISDN

A new switching architecture for broadband ISDN, "Synchronous Composite Packet Switching (SCPS)," is proposed and evaluated. It efficiently integrates circuit and packet switching functions on a single switching system and accommodates very high speed-up to several tens of Mbit/s-communication services, such as very high speed bursts of data, still picture, and motion video, as well as 64 kbit/s or less voice and data services. The SCPS system comprises plural switch modules and plural Very high speed synchronous loops. In the SCPS system, messages on plural circuit switched channels are assembled into quasi-packets, called "composite packets," and switched synchronously between switch modules, maintaining complete time transparency and short absolute delay time. A system parameter design to obtain high system efficiency and appropriate system modularity is explained, and an example for a very large capacity transit switch of 4 Gbit/s throughput is presented. System implementation problems to realize the SCPS principle, such as efficient implementation of the composite packet assembling and loop transmission functions, are investigated and an experimental system constructed for circuit switching part is presented. The most remarkable characteristic of the SCPS is that it efficiently integrates64 times nkbit/s circuit switching with packet switching. Moreover, the SCPS system retains compatibility with existing networks and the possibiliy of evolution toward a future broadband ISDN. On the basis of the above investigations and experimental system construction, the authors conclude that the SCPS is one of the most practical switching architectures for the coming broadband ISDN era.     

Regulatory mechanism of pepsinogen gene expression in monolayer cultured guinea pig gastric chief cells

We have investigated the effects of dibutyryl cAMP, forskolin, carbamylcholine chloride (carbachol), ionomycin, and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the expression of guinea pig pepsinogen mRNA in monolayer cultured gastric chief cells. After exposure of the cells to each of these compounds for 4 to 24 hr, and at 48 hr after primary culture, total cellular RNA was isolated using acid guanidium-phenol-chloroform and then was reverse transcribed to cDNA. Obtained cDNA was amplified by polymerase chain reaction (PCR) using primers detecting guinea pig pepsinogen mRNA and human beta-actin mRNA as an internal standard. The PCR products were separated and quantified using capillary electrophoresis. Dibutyryl cAMP and forskolin significantly increased pepsinogen mRNA, but carbachol, ionomycin, and TPA failed to increase that. These findings suggested that pepsinogen gene expression was up-regulated by intracellular cAMP, but not by intracellular calcium or protein kinase C in guinea pig chief cells.     

Correlation between the cold-working and aging treatments in a Cu-15 Wt Pct Cr in situ composite

The cold-working and aging treatments are the two most important materials processing techniques used to produce the high strength and high conductive Cu in situ composites. In this work, we systematically investigated the relationship between these two techniques in a Cu-15 wt pct Cr in situ composite by means of the electrical conductivity measurement, hardness testing, tensile testing, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In contrast to the solution-treated samples, the cold working significantly improves the electrical conductivity but only produces a moderate hardening effect during the subsequent aging treatment. This is attributed to the rapid precipitation of incoherent Cr phases due to the high vacancy density in the Cu matrix after the cold deformation. At high aging temperature, the hardness and tensile strength of the material decreases significantly due to a pronounced process of recovery and recrystallization in the Cu matrix, as well as the recovery in the Cr fibers. When aged for 1 hour, an optimum aging temperature of 715 K is recommended.     

Inhibition by angiotensin II type 1 receptor antagonist of cardiac phenotypic modulation after myocardial infarction

The purpose of this study was to examine the cardiac phenotype and remodeling after myocardial infarction and the effect of the angiotensin II type 1 (AT1) receptor antagonist (TCV-116) on the gene expression. Myocardial infarction in rats was produced by ligation of the coronary artery. TCV-116 (10 mg/kg/day) was administered orally to rats from 1 day after myocardial infarction. At 1, 2 and 3 weeks after myocardial infarction, blood pressure and heart rate were measured, and the heart was removed. The left ventricle was measured for infarct size and weight, and then the total RNA from the non-ischemic left ventricle was extracted. mRNAs in the non-ischemic left ventricle were measured by Northern blot analysis. The weight of the non-ischemic left ventricle was significantly increased 3 weeks after infarction. This was completely prevented by TCV-116 treatment. mRNA levels for beta-myosin heavy chain (beta-MHC), atrial natriuretic polypeptide (ANP), collagen types I and III and transforming growth factor-beta 1 (TGF-beta 1) in the non-ischemic left ventricle were increased by a factor of 3.0, 6.7, 7.9, 4.0 and 1.4 (P < 0.01), respectively, 1 week after infarction. There was no increase in alpha-skeletal actin mRNA at 1 and 2 weeks, but it was increased by a factor of 2.9 (P < 0.05) at 3 weeks. On the other hand, there was no change in alpha-MHC mRNA during the 3 weeks. TCV-116 significantly suppressed the increased gene expression of beta-MHC and alpha-skeletal actin in the non-ischemic myocardium at all time points, and also suppressed the expression of ANP at 2 and 3 weeks. However, TCV-116 failed to inhibit the expression of collagen I and III mRNAs at 1 and 3 weeks. These results show that myocardial infarction causes a rapid shift of myocytes to fetal phenotype and a rapid activation of collagen genes in the non-ischemic myocardium. AT1 receptor may be responsible for the phenotypic modulation of myocytes following myocardial infarction.     

Sugar-Induced Chiral Orientation of Boronic-Acid-Appended Amphiphile Clusters Formed in the Dipalmitoylphosphatidylcholine (DPPC) Membrane

A boronic-acid-appended amphiphile bearing an azobenzene chromophore in the chain center ( 3 ) was synthesized. Although 3 could not form the membrane-like, ordered aggregate by itself, it formed a phase-separated aggregate in a dipalmitoylphosphatidylcholine (DPPC) matrix membrane. When saccharides were added, the boronic acid group reversibly formed the saccharide complexes, and 3 in the DPPC matrix membrane became CD-active with the appearance of exciton-coupling bands. Comparison of the saccharide absolute configuration with the CD intensity established that the saccharide possessing the OH group (as 3-OH, 4-OH, and 5-CH₂OH) in the same side as the cis-1,2-diol gives the strong CD band. Judging from the structure of 3 –saccharide complexes, these “same-side” OH groups can enjoy intermolecular hydrogen-bonding interactions, which eventually induce the chiral orientation of azobenzene chromophores. This is a novel membrane system useful to read out the information stored in the saccharide structure and to create novel membrane structures by added saccharides.