Two genes encoding acyl-CoA dehydrogenases, acdA and acdB, arranged in tandem, were found in the chromosomal DNA of Acinetobacter sp. strain M-1. AcdA was purified from the parental strain and AcdB was purified from an Escherichia coli strain expressing the cloned gene. The substrate specificities of the two enzymes suggest that AcdA is a medium-chain acyl-CoA dehydrogenase and that AcdB is a long-chain acyl-CoA dehydrogenase. Characterization of n-alkane metabolism in Acinetobacter sp. strain M-1 has revealed parallel pathways as well as enzymes with overlapping specificities in a single pathway. The two acyl-CoA dehydrogenases described here provide another example of the physiological complexity underlying n-alkane utilization. 相似文献
To examine whether one-dimensional (1D) helium quantum fluid is realized in narrower channels than those studied previously, we have measured heat capacities of 4He adsorbed in nanoporous material FSM with straight 1D channels 1.5 nm in diameter. From the heat of desorption for adsorbed 4He, the coverage nf, up to which 4He film grows in the channels, is determined to be 15.4 ??mol/m2 using the Frenkel-Halsey-Hill model. At coverages sufficiently below nf, the temperature dependence of the 4He heat capacity has a shoulder, above which adsorbed 4He is delocalized from the substrate. On the other hand, the depression of the heat capacity indicating quantum effects has not been observed up to nf, which suggests that 4He film in the channels remains amorphous-like normal fluid. Just above nf, the quantum effect is observed in 4He adatoms on the grain surface of FSM powder, which indicates that 1.5 nm channels are slightly below the limit required to realize quantum effect in the inside 4He fluid. 相似文献
This paper discusses the acculturation of Japanese descents through the approach of exploratory data analysis. When considering acculturation, it may be common sense to consider that Sansei are more assimilated with the culture of the immigrated country than are Nisei. While observing the survey results, the question “Is this really true?” occurred to me. The point of the study is to examine, by extensive sample surveys, the hypothesis that acculturation among generations of immigrants is of two types, namely: ‘natural acculturation’ and ‘a tendency of turning toward the Japanese way of thinking.’ This is considered to be an important point when the acculturation of a race is considered.
The author deals with the degree of acculturation among generations of Japanese Americans and Japanese Brazilians, based on international comparative survey results among the host society, ethnic society and different immigrant groups consisting of several generations.
The results supported the hypothesis that acculturation among generations of immigrants is of two types. Possible factors related to socio-education may also exert effects on their attitudes and values.
We demonstrate a method for successfully controlling carbon incorporation in AlAs layers grown by atomic layer epitaxy (ALE) using various GaAs substrates with different orientations. The number of alkyl radicals attached to an Al atom at the surface, which is a main factor in carbon incorporation, can be intentionally controlled by changing substrate orientation. We found that the carbon incorporation in ALE-AlAs using the (3 1 1)B surface is 2 x 1017,cm-3, which is the lowest value ever reported for ALE-AlAs that satisfies one-monolayer self-limiting growth conditions. 相似文献
A water-swollen hydrogel with a molecularly-ordered structure was prepared by copolymerizing acrylic acid and acrylic monomer containing hydrophobic long alkyl or mesogenic moiety. The gels with a long alkyl side chain formed the crystalline structure and undergo the reversible order–disorder transition with change in temperature or solvent composition which accompanied a dramatic change in Young's modulus. These gels exhibited such chemomechanical behaviors as the shape memory and the rotational motility on the water surface. On the other hand, the gels with the mesogenic side chain formed the liquid crystalline structure with polymorphism in water, and mesophase diagram was established by changing copolymer composition and water content. Mechanism of these structural and chemomechanical behaviors has been explained in terms of order–disorder transition. 相似文献
A field ion microscope has been used to investigate the influence of oxygen adsorption on adhesion of W to Au. An adhesion contact in ultrahigh vacuum of the field ion microscope was carried out using a W tip either with or without oxygen adsorption. It was found that adhesion force decreased with increasing oxygen exposures up to 60 Langmuirs (L). With an oxygen exposure of 16 L, an intermediate adhesion resulted. Adhesion is thus dependent upon the coverage of oxygen. The depth of adhesion-induced lattice defects was studied using the field evaporation technique. Over 200 L, adhesion force was not detectable, nor was distortion of W atoms. 相似文献
Pseudoelasticity in Fe3Al single crystals with different Al contents was investigated focusing on the dislocation configuration and the ordered domain structure. Giant pseudoelasticity only appeared in the D03-ordered Fe3Al single crystals, while the B2-ordered crystals and those with the disordered phase exhibited small strain recovery. The amount of shape recovery in the D03-ordered crystals showed a maximum near 23.0at.%Al and decreased with increasing deviation from this Al concentration. In the D03 phase at 22.0–25.0at.%Al, 1/4[1 1 1] superpartial dislocations moved individually dragging the nearest-neighbour antiphase boundaries (NNAPB), while couplets of the superpartials were observed to bow out, dragging the next-nearest-neighbour antiphase boundaries (NNNAPB) in Fe–28.0at.%Al. In Fe–22.0–25.0at.%Al single crystals, the NNAPB pulled back the superpartials to decrease its energy during unloading, resulting in the giant pseudoelasticity. In contrast, the surface tension of the NNNAPB was lower than that of the NNAPB, leading to the small strain recovery in Fe–28.0at.%Al. 相似文献
OBJECTIVE: To explore whether there are different disease patterns of rheumatoid arthritis (RA) in women and men. METHODS: We studied 55 male case patients and 110 female control patients who developed RA between 1970 and 1985 and who resided and received medical care in Olmsted County, Minnesota, for at least 10 years after the diagnosis of RA. Case and control patients were matched for the date of first diagnosis. The pattern and extent of joint involvement, the frequency of joint surgeries, and the presence and type of extraarticular manifestations were determined by retrospective chart review. RESULTS: Incidence rates in women were variable and age dependent, whereas the risk in men older than 36 years was constant over their lifetime. Erosive disease was more frequent in men than in women (72% versus 55%, respectively; P < 0.05) and tended to occur earlier (47% versus 31% for erosive disease within the first 4 years of RA). Although male sex was correlated with a higher risk of bony erosions and an accelerated course of RA, structural consequences of joint destruction were more pronounced in women. Joint surgery was performed more frequently in women (50%) than in men (27%) (P = 0.01). In particular, the frequencies of arthroplasties and arthrodeses of hand and foot joints were different (34 procedures in women versus 1 procedure in men; P < 0.001). Sex influenced the risk as well as the pattern of organ involvement in RA. Nodules and rheumatoid lung disease were typical manifestations in men (P = 0.001 and P < 0.001, respectively), whereas women typically developed sicca syndrome (P = 0.05). Despite differences in disease aggressiveness and disease pattern, there was little difference in the medical therapy in the men compared with the women. CONCLUSION: RA is a heterogeneous disease with variations in phenotype. Sex-associated factors influence disease severity as well as disease pattern. Because sex-related effects influence treatment goals, treatment responses, and side effects, they should be considered in clinical study design and analysis as well as in the treatment decisions for individual patients with RA. 相似文献
Oxygen vacancies can be introduced into zirconia solid solution ZrO2–MO u ( u = 1 and 1.5) to maintain electroneutrality. Recently, the local structures around Zr4+ and M2 u + ions in ZrO2–MO u solid solutions have been studied through EXAFS spectroscopy, diffuse scattering analysis, and single-crystal structure analysis. The present study constructs an ion-packing model for zirconia solid solutions based on some defect cluster models. The decrease of cell volume with the occurrence of vacancies is assumed to be expressed by decreasing the coordination number (CN) of cations around the vacancy. The distribution of CNs in a solid solution was calculated from a certain defect cluster model. The average interatomic distances, the average CN, and the short-range order parameters were calculated using this distribution of CNs. The local structures calculated from the model were compared with experimental data in the systems ZrO2–MO1.5 (M = Y, Gd, Yb, and Ca). In the ZrO2–YO1.5 system, the r (s–O) interatomic distance, where s represents Zr4+ or Y3+ and O represents O2−, decreased with Y content and therefore vacancy content. The probability of finding Y3+ around a vacancy increases with increasing yttria content from a comparison of the calculated results with the ones from recent EXAFS studies. The present model can qualitatively explain compositional and size dependences of the dopant on various local structures. 相似文献
A reactor system, which continuously hydrolysed the metal alkoxide in an alcohol solution, was designed using an electromagnetic
stirrer and an ageing tube. Several monosized colloidal particles were produced by this reactor system, which had high reproducibility
and reliability for long-term production. The relation between powder characteristics and experimental parameters such as
reagent concentration, mixing rate, ageing time, temperature, was investigated. These parameters had an effect on the particle
size, size distribution, morphology and state of agglomeration. It is possible to control the particle size to between 0.1
and 1.0 μm by varying the experimental conditions. A narrower size distribution of powders was obtained by using an electromagnetic
stirrer with greater flow rate. Physical and chemical properties of monosized colloidal particles obtained by this reactor
were comparable to those of monosized colloidal particles obtained by the batch process. 相似文献