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41.
M Fukasawa K Hirota H Adachi K Mimura K Murakami-Murofushi M Tsujimoto H Arai K Inoue 《Canadian Metallurgical Quarterly》1995,270(4):1921-1927
Macrophage scavenger receptors mediate the recognition of a wide range of negatively charged macromolecules including acetylated low density lipoproteins (AcLDL). Chinese hamster ovary (CHO) cells were cultured in the presence of increasing concentrations of simvastatin, a cholesterol biosynthesis inhibitor, and AcLDL as the sole source of exogenous lipoproteins. The cells surviving under these conditions specifically bound 125I-labeled AcLDL with high affinity and degraded them via an endocytic pathway. Unexpectedly, the association and degradation of 125I-labeled AcLDL by these CHO cells were not inhibited by dextran sulfate, fucoidan, and polyinosinic acid, competitors of macrophage scavenger receptors, but were completely inhibited by maleylated bovine serum albumin. Furthermore, these cells effectively took up negatively charged liposomes containing acidic phospholipids such as phosphatidylserine and phosphatidic acid, whereas CHO cells expressing macrophage scavenger receptors did not. AcLDL and negatively charged liposomes were cross-competed with each other. Northern blot analysis using the cDNA for the macrophage scavenger receptor revealed that these CHO cells did not express this receptor. From these observations, we conclude that the isolated CHO cells express a novel type of AcLDL receptor, which is distinct from macrophage scavenger receptors with respect to ligand specificity and competitor sensitivity. 相似文献
42.
A high-speed and error-free voiceband data communication method using a hybrid automatic repeat request (ARQ) protocol over an analog cellular system is described. The present method adopts an adaptive error control scheme. This error control scheme automatically selects the optimal error correction code according to circuit bit error rate (BER), so as to match it to the frequently changing mobile radio propagation path conditions. This method adopts multiframe rejection as a retransmission scheme for a high throughput efficiency on the burst error circuit. Actual field evaluation was made by mounting this protocol on a CCITT V.22 bis modem with a data transmission speed of 2400 b/s and a modulation method using 16 carrier states over the Advanced Mobile Phone Service (AMPS) in Atlanta, GA, verifying that data communications can be achieved with an average throughput efficiency of 70% over a radio channel having a BER up to 10-2 相似文献
43.
Yuji Sasaki Ryo Yoshimitsu Syouhei Nishihama Yuma Shimbori Hidenobu Shiroishi 《分离科学与技术》2017,52(7):1186-1192
A new extractant biuret(C8) is synthesized and tested for solvent extraction of hard acid metals, for example, actinides, and soft acid metals. This compound has a central frame similar to that of malonamide but with an additional amino functional group introduced into the central framework; in this case, both the amidic oxygen atoms and the amino nitrogen atom may bond with metals. We found that both hard and soft acid metals can be extracted from nitric or perchloric acids to n-dodecane using biuret(C8). It is clear that D(Pd, Pu, U) values of approximately 100 can be obtained using 0.1 M biuret(C8)/n-dodecane. 相似文献
44.
45.
The mechanism of the self-assembly of the lamellar structure of natural stratum corneum lipids (SCL) has been a subject of
considerable interest. We have examined this question by using a synthetic pseudo-ceramide (sphingolipid E, SLE) which was
analogous to the naturally occurring ceramide type 2. The thermotropic properties and the structural characteristics of SLE,
together with other main components of SCL, fatty acids, and cholesterol, were investigated by differential scanning calorimetry
and X-ray analysis. A mixture of SLE and stearic acid was in a stable α-form having a lamellar structure, which is very similar
to that of natural SCL. However, lipid mixtures in which stearic acid were replaced by oleic acid did not form lamellar structures,
and existed in the crystalline states. This indicates that the stable bilayer formation of the natural SCL is strongly dependent
on the molecular fatty acid structure. Moreover, incorporation of cholesterol (0–50%) into equimolar mixtures of SLE/stearic
acid and of SLE/oleic acid caused a marked decrease of melting entropies, while the aggregation states of both systems were
not changed. This effect of cholesterol can be attributed to the disorder of the molecular packing. These results suggest
that the hydrophobic interactions between the SCL are important for bilayer formation as are the hydrophilic interactions
between the polar groups. 相似文献
46.
Yoshiyuki Sato Ming Wang Shigeki Takishima Hirokatsu Masuoka Taku Watanabe Yoshihito Fukasawa 《Polymer Engineering and Science》2004,44(11):2083-2089
The solubility of butane and isobutane in molten polypropylene (PP) and polystyrene (PS) was measured at pressures up to 3 MPa and along four isotherms from 438 to 483 K for PP and from 348 to 473 K for PS. The solubility increased with increasing pressure and decreasing temperature. At 438 K and 2 MPa, the solubilities of butane and isobutane in PP were 0.15 and 0.11 g‐gas/g‐polym, respectively. At 423 K and 2 MPa, the solubilities of butane and isobutane in PS were 0.08 and 0.05 g‐gas/g‐polym, respectively. Solubility could be correlated with the Sanchez‐Lacombe equation of state with temperature‐dependent binary interaction parameters to within 4.4% average relative deviation. Henry's constant for these gases in the PP and PS obtained in this work were used to determine correlation equations along with literature data. Polym. Eng. Sci. 44:2083–2089, 2004. © 2004 Society of Plastics Engineers. 相似文献
47.
Yasuo Hatate Yoshimitsu Uemura Mitsunobu Migita Yoshinobu Kawano Yasuhiko Tanaka Kazuya Ijichi D.F. King 《Chemical Engineering Communications》1991,101(1):39-44
A semi-cylindrical fluidized bed of 15 cm internal diameter, equipped with a transparent flat glass plate for the front wall, was employed to visually observe bubbles in the bubbling to slugging transition regime and in the slugging regime. Five kinds of perforated distributors were used to investigate the effect of distributor type on the bubble size and the bubble rise velocity. The average bubble size was not affected by distributor type in these flow regimes, and could be predicted by Darton et al's correlation (1974)of hole number 22. In other words, this comes from the inapplicability of the correlation to the slugging regime. The bubble rise velocity agreed well with Allahwala et al's correlation (1979) and was not affected by the type of distributor. 相似文献
48.
49.
Yoshikatsu Ogawa Yoshimitsu Yamazaki Masato Kodaka Hiroaki Okuno 《Journal of the American Oil Chemists' Society》1998,75(12):1161-1166
A simple method for intraliposomal entrapment of platinum complexes is presented, where hydrophilic platinum oligonuclear complexes, 1-methyluracil green (MeUG), uridine green (UdG) and uridine blue (UdB), are included inside liposomes and allowed to react with bilayer lipids. The liposomes prepared in this method exhibit higher entrapment efficiency and higher distribution to organs (liver, kidney, spleen, lung) and blood (but not B16 cancer cells) than those prepared from mononuclear Pt complexes [cis-diamminedichloroplatinum, cis-diammine-1,1′-dicarboxylatocyclobutaneplatinum, and cis-dichloro-cis-dihydroxy-trans-bis(isopropylamine)platinum)]. 相似文献
50.
A new calorimeter for measurements of the heat capacity and magnetocaloric effect of small samples in pulsed magnetic fields is discussed for the exploration of thermal and thermodynamic properties at temperatures down to 2 K. We tested the method up to μ(0)H=50?T, but it could be extended to higher fields. For these measurements we used carefully calibrated bare-chip Cernox(?) and RuO(2) thermometers, and we present a comparison of their performances. The monotonic temperature and magnetic field dependences of the magnetoresistance of RuO(2) allow thermometry with a precision as good as ±4 mK at T=2?K. To test the performance of our calorimeter, heat capacity and magnetocaloric effect for the spin-dimer compound Sr(3)Cr(2)O(8) and the triangular lattice antiferromagnet RbFe(MoO(4))(2) are presented. 相似文献