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A new reactor system was designed for an integrated process involving photoelectrocatalytic oxidation (PECO) and electro-Fenton (E-Fenton) oxidation. Its efficiency was evaluated in terms of 2,4-dichlorophenol (2,4-DCP) degradation in aqueous solution. In this process, a TiO2 electrode and an iron (Fe) electrode were used as anodes in parallel, while graphite felt (GF) was used as a cathode. When an electrical current is applied between the anodes and the cathode, the iron anode can release Fe2+ and the GF cathode can generate H2O2 continuously in the reaction solution. Under UV-A illumination, while a H2O2-assisted PECO reaction occurs on the surface of the TiO2 photo anode, an E-Fenton reaction takes place in the solution. The experimental results demonstrated that 2,4-DCP degradation in aqueous solution was greatly enhanced because of the interaction between the two types of reactions. Moreover, the effect of pH as an important factor was investigated. It was found that the combined reaction becomes less pH sensitive than the typical E-Fenton reaction and may be suitable for application in a wide pH range.

A new hexagonal aluminium–chromium–nickel phase, Al14.4Cr3.4Ni1.1, is described. The structure includes 12 icosahedral clusters in a unit cell, each of which consists of a transition metal (TM) atom at the center and 11 aluminium and one TM atom on the fivefold vertices of the icosahedron. Pairs of the clusters are linked along the c axis by sharing a triangular face. Two pairs of the clusters are joined by two trigonal antiprisms, constructing a column along the c axis. Six such columns are included in a unit cell and form the crystal structure. The second neighboring atoms connecting the columns are on the threefold axes of the icosahedral cluster.

The three-dimensional (3D) structure of the huge quasicrystal approximant nu-AlFeCr (space group P6(3)/m, a = 40.687 and c = 12.546 A) was solved by electron crystallography. High-resolution transmission-electron-microscopy (HREM) images and selected-area electron diffraction patterns from 13 different zone axes were combined to give a 3D potential map. 124 out of 129 unique atoms were found in the 3D map. Procedures for ab initio structure determination by 3D reconstruction are given. It is demonstrated that 3D reconstruction from HREM images is very powerful for solving structures--even very complicated ones. There is no limit in terms of the number of unique atoms in a structure that can be solved by 3D reconstruction.

To establish the quality standards for fuyanke(FYK) granule.The phellodendron Chinese schneid, polygonum cuspidatum, sieb. et Zucc and glycyrrihza uralensis fisch in FYK granule were identified by thin-layer chromatography(TLC). The contents of berberine were determined by thin-layer chromatographic scanning(TLCs).The average recovery rate was 97.86%, and the relative standard deviation 1.96%.The method is simple, accurate and reliable.

Fine particles of alpha -Fe or Fe(Co) are prepared by the reduction in H/sub 2/ of gamma -FeOOH or Co-ferrite particles which have been wrapped in monomolecular layers of exfoliated MoS/sub 2/. The presence of the MoS/sub 2/ restricts coalescence of the starting particles while allowing the reduction to take place. Magnetic moments and coercivities are determined at temperature during processing. Results are given for magnetization measurements, electron microscopy, Mossbauer effect spectroscopy, and X-ray diffraction. Enhanced coercivities are observed when MoS/sub 2/ is present. Surface pinning is deduced from the approach to magnetic saturation. >

Cobalt ferrite, CoxFe3−xO4 with 0.55≤x≤0.8, is produced by precipitation from aqueous solutions. Drying and annealing at temperatures below 300 °C results in a coercivity that increases with increasing temperature. Mossbauer effect spectroscopy and magnetic measurements are consistent with the interpretation that these Co ferrites have a (mostly) normal spinel structure as made. These convert to a (mostly) inverse spinel structure on thermal aging. No significant morphological changes occur during this transformation. Coercivities as high as μ0Hc=0.2 T are observed.

Monomolecular layers of exfoliated MoS2 are incorporated in the process of the formation of Co ferrite from aqueous solutions. The presence of MoS2 is found to limit the coalescence of particles during reduction to Fe(Co) metal. That MoS2 inhibits the full conversion to metal is confirmed by Mossbauer effect spectroscopy. Magnetization measurements are interpreted on the basis of noncollinear magnetization patterns resulting from competing surface anisotropies.

The paper discusses mainly about the modelling process and related problems with examples from Chinese and French cases. Five practical problems must be solved for modelling the functioning of any landscape: (1) The field data are necessarily taken with a sampling procedure that implies a spatial (and often temporal) scale. (2) Every landscape modelled has to be identified, delimited and characterised before application of the hierarchical theory. (3) The functioning of a landscape involves data of multiple types (climate, soil, vegetation, fauna, buildings, communications, economy, aesthetics, etc.) which must be integrated in a holistic approach. (4) Every landscape is spatially heterogeneous, and the structure of the model must be more or less isomorphic with its heterogeneity. (5) The evolution of the landscape must be modelled on a rather long period of time. For all these reasons, it is necessary to build ad hoc models. Object-oriented computing languages may be useful for this purpose.

The maize CMS-S near isogenic line (NIL) developed by author and the backcross progeny (BC1) derived from it were used to identify molecular markers linked to the Rf3 gene and subsequently determine its chromosomal location on the linkage map of maize. Bulk segreant analysis was performed using AFLP technique. From the survey of AFLP primer combination, two AFLP markers, (EcoRI-AGG/MseI-CAC and EcoRI-AAC/MseI-CAG), which were named RR6 and RR7 respectively, linked to the Rf3 gene were identified. However, AFLP marker RR6 showed polymorphism between parents, and bulks were used to survey the available 100 individuals of the BC1 population, 2 out of 100 shed recombination. The recombination-rate was 2%. The genetic distance between Rf3 gene and AFLP marker RR6, was approximately 2.0 cM. And then, the RR6 was successfully cloned and sequenced, primer synthesized and converted to SCAR marker so that PCR marker can be developed for the marker-assisted selection. In RFLP analysis, marker RR6 linked to Rf3 was found to be located between RFLP loci asg20 and php20581b, and mapped on chromosome 2L.

We describe a new member of the 17beta-hydroxysteroid dehydrogenase group of enzymes. Human Pan1b displays greatest activity with 5alpha-androstan-3alpha,17beta-diol (3alpha-Diol) as substrate, suggesting that it may be important in androgen metabolism. Enzymic activity was non-saturable with 3alpha-Diol but saturable with retinoids, although retinoids were not metabolized. Immunohistochemical studies on 10% formalin fixed and paraffin embedded sections of human tissues showed that Pan1b was present in acini and ciliated epithelia of the lung. In the fetus immuno reactivity was present in ciliated epithelia throughout gestation and staining appeared to be stronger in the second half of pregnancy. Pan1b was also expressed in the nonpigmented epithelium of the ciliary body, and in adrenocortical tumor cells. Although 3alpha-Diol is generally considered a degradation product of androgen metabolism it could have its own biological function. Pan1b may be an important modulator of the endocrine, or intracrine activity of this steroid.

When small intestinal epithelial cells are incubated with [3H]corticosterone, nuclear binding is displaced neither by aldosterone nor RU-28362, suggesting that [3H]corticosterone is binding to a site distinct from mineralocorticoid receptor and glucocorticoid receptor. Saturation and Scatchard analysis of nuclear [3H]corticosterone binding demonstrate a single saturable binding site with a relatively low affinity (49 nM) and high capacity (5 fmol/μg DNA). Competitive binding assays indicate that this site has a unique steroid binding specificity, which distinguishes it from other steroid receptors. Steroid specificity of nuclear binding mirrors inhibition of the low 11β-dehydrogenase activity, suggesting that binding may be to an 11β-hydroxysteroid dehydrogenase (11βHSD) isoform, although 11βHSD1 is not present in small intestinal epithelia and 11βHSD2 does not colocalize intracellularly with the binding site. In summary, a nuclear [3H]corticosterone binding site is present in small intestinal epithelia that is distinct from other steroid receptors and shares steroid specificity characteristics with 11βHSD2 but is distinguishable from the latter by its distinct intracellular localization.

Hemoglobin of the Gram-negative bacterium Vitreoscilla can bind oxygen strongly and reduce the oxygen requirement of the bacterium. A recombinant plasmid pAV was constructed by inserting the hemoglobin gene (Vgb) to the downstream of the promoter of beta-lactase gene of the B. subtilis plasmid pAK4. The plasmid pAV was transferred into strain DB104, G331 (a subtilisin-producing B. subtilis) and B53 (a xylanase-producing B. subtilis). The subclones and transfer of the Vgb gene into pAK4 were detected and confirmed by Dot blotting and electrophoresis analysis. The expression of homoglobin was measured by recording CO-difference spectra after bubbling CO into the sample cuvette. The production of subtilisin and xylanase was increased in the fermentation of the Vgb-expressing strains. These results provided a new way to reduce the oxygen requirement and to increase the biomass production in the fermentation industry.

Fe(Co)5 is thermally reduced to Fe(C) in the presence of monomolecular flakes of MoS2. The magnetic properties of particles produced by the decomposition of Fe(CO)5 and subsequent thermal annealing are described. Comparison of the properties of primarily χ‐Fe5C2 carbides prepared with and without the presence of MoS2 flakes show that enhanced coercivity is achieved by including MoS2 in the processing.

Organic solvent-tolerant mutants of Pseudomonas aeruginosa selected in the presence of hexane exhibited increased resistance to a variety of structurally unrelated antimicrobial agents, including beta-lactams, fluoroquinolones, chloramphenicol, tetracycline, and novobiocin, a phenotype typical of nalB multidrug-resistant mutants. Western immunoblotting with antibodies specific to components of the three known multidrug efflux systems in P. aeruginosa demonstrated that the solvent-tolerant mutants displayed increased expression of the MexAB-OprM system and decreased expression of the MexEF-OprN system. Sequence analysis of mexR, the repressor gene of mexAB-oprM efflux operon, identified a nonsense mutation and a point mutation in the mexR genes of two solvent-tolerant mutants. These results emphasize the importance of the MexAB-OprM efflux system in organic solvent tolerance and the ability of environmental pollutants to select bacteria with a medically relevant antibiotic-resistant phenotype.

Short chain alcohol dehydrogenases have an invariant YXXXK motif at the active site. Database analysis of 116 superfamily members showed that 92% also contain a Serine or Threonine residue at the Y + 1 or Y + 3 positions, a pattern we previously described as the ST rule. In the present study we have mutated Serines in the active site, YSASK, motif of 11 beta-hydroxysteroid dehydrogenase type I (11 beta HSD1). These studies were facilitated by the generation of a new specific polyclonal antibody (RAH113) raised against a synthetic peptide derived from the rat 11 beta-HSD1 sequence. Immunopurified RAH113 recognized a single band at 34 kDa in liver homogenates. Kinetic analysis of equivalent amounts of wild type and mutant proteins showed that mutagenesis of active site Serines resulted in modest increases of Km values for corticosterone from 325 nM for 11 beta HSD1 to 512 nM-588 nM for the S1 (YAASK), S2 (YSAGK) and S3 (YAAGK) mutants in homogenates of transfected CHOP cells. However, far greater effects were observed on the first order rate constants with mutants displaying 10%, 1% and 1% of the wild type activity, respectively. When the oxidoreductase reaction was studied in whole cells mutagenesis again had a minimal effect on the Km value but dramatically lowered first order rate constants to 34%, 5% and 6%, respectively, of the wild type. These data show that Serines at the active site of 11 beta HSD1 play an important role in determining the rate of catalysis. Coexpression of wild type and mutant enzymes did not lower wild type activity suggesting that the active site of the multimeric enzyme is not a composite of active site Serines from different subunits.

The 11beta-hydroxysteroid dehydrogenase type 2 enzyme (11betaHSD2) metabolizes glucocorticoids into their inactive 11-keto metabolites. Although the type 1 enzyme (11betaHSD1) displays both oxidative and reductive activity, to date 11betaHSD2 has been shown to have dehydrogenase activity only. In this study we compared both dehydrogenase and reductase characteristics of the cloned rat 11betaHSD1 and rat and human 11betaHSD2 for three different 11-hydroxysteroid substrates, cortisol (F), corticosterone (B), and dexamethasone (Dex), and the corresponding 11-keto metabolites, cortisone (E), 11-dehydrocorticosterone (A), and 11-dehydrodexamethasone (DH-Dex), respectively. In cell homogenates expressing either the rat or the human 11betaHSD2, the relative potency for the dehydrogenase reaction was BFDex. Although there was no reduction of A or E, DH-Dex was readily converted to Dex with an equilibrium far on the side of the 11-hydroxy metabolite. DH-Dex reduction in homogenates was inhibited by both glycyrrhetinic acid and carbenoxolone, with a 50% inhibition at 80 and 100 nM, respectively. In intact cells transfected with rat 11betaHSD1, the equilibrium was on the reductase side for all substrates. Dehydrogenation of B or F was more potent with rat 11betaHSD2 than with rat 11betaHSD1. There was no detectable 11betaHSD1 oxidation of Dex. These data indicate that both the cloned human and rat 11betaHSD2 reduce DH-Dex and do this more readily than they oxidize Dex. Thus, 11betaHSD2 seems also to be a bidirectional enzyme, although no reduction of the physiological compounds A and E was observed.

Mineralocorticoid action is facilitated by 11 beta-hydroxysteroid dehydrogenase type II (11 beta HSD2), which metabolizes glucocorticoids and allows aldosterone to bind to the nonselective mineralocorticoid receptor. We have recently demonstrated the presence of the 11 beta HSD2 protein in a wide range of human epithelia, suggesting that it is the sole isoform endowing specificity in man. In the present study we have used an immunopurified polyclonal antibody (RAH23) raised against a C-terminal peptide derived from the cloned rat 11 beta HSD2 protein to perform immunohistochemical and molecular analysis in rat tissues. In frozen sections of rat kidney, strong staining was seen with the RAH23 antibody in the distal tubule; weaker staining was observed in the thick ascending loop of Henle and the medullary and papillary collecting ducts. Punctate cortical staining was observed in the fetus at 20 days gestation and in 8-day-old rats, with a noticeable increase in the staining pattern at 16 days of age. The kidney did not attain the adult pattern of staining until 28 days of age. Epithelia of ileum and colon also stained with RAH23, as did excretory ducts of the submandibular gland. Intrahepatic and excretory bile ducts displayed strong immunoreactivity in the epithelial lining. Rat adrenal glands showed evidence of the 11 beta HSD2 antigen in the zona fasciculata and zona reticularis, but not in the zona glomerulosa or medulla. Western blot analysis with the RAH23 antibody revealed strong bands in the kidney, colon, adrenal gland, and submandibular gland at 40 kDa, colinear with the migration of the cloned 11 beta HSD2 enzyme. A band of medium intensity was also seen at this size in the pancreas, whereas a band of moderate intensity was seen in the bile duct, and weaker bands were noticed in the stomach, small intestine, and liver, with a diffuse band at 36-42 kDa in the prostate. Strong bands were seen in the pancreas and prostate at 78 kDa, with weaker signals in the colon, adrenal, stomach, and bile duct. A number of tissues also displayed multiple bands at about 30 kDa. Enzymatic assays on tissue homogenates showed extensive conversion of corticosterone to its 11-dehydro product in an NAD-dependent manner in the submandibular gland, adrenal gland, and kidney, but not in the pancreas or prostate. This study confirms the ubiquitous presence of 11 beta HSD2 in sodium-transporting epithelia, demonstrates the high level of 11 beta HSD2 protein and enzyme activity in the rat adrenal, and suggests a possible role for the enzyme in the biliary system. Further studies are required to determine the relevance of the various molecular species to the activity, latency, and processing of the enzyme.

The 11 beta-hydroxysteroid dehydrogenase type II enzyme (11 beta HSD2) converts cortisol into mineralocorticoid receptor inactive cortisone, thus preventing occupation of the non-selective mineralocorticoid receptor by glucocorticoids in the kidney. Mutations generating inactive enzymes have been described in the HSD11B2 gene in the congenital syndrome of apparent mineralocorticoid excess (AME), although proof of mutant protein synthesis was not provided. In the present study we have examined the metabolism of cortisol in mammalian cells transfected with plasmids expressing the wild type and mutant enzymes from three additional families of patients with mutations in the HSD11B2 gene. These studies revealed that the mutants were enzymatically inactive in intact mammalian cells expressing significant levels of both full length and truncated proteins. This is the first study to definitively show that point mutations in the HSD11B2 gene abolish 11 beta HSD2 enzymatic activity in the syndrome of AME.

11 beta-hydroxysteroid dehydrogenase (11-HSD) activity allows aldosterone occupancy of mineralocorticoid receptors by inactivating endogenous glucocorticoids. The expression of the 11-HSD2 gene, a low Km, NAD+ dependent species of 11-HSD, was found in several discrete areas of the rat brain by in situ hybridization. Cells strongly positive for 11-HSD2 mRNA were found in the commissural portion of the nucleus tractus solitarius, subcommissural organ and ventrolateral ventromedial hypothalamus. Scattered labeled cells were also seen in the medial vestibular nucleus. The expression of 11-HSD2 mRNA in the brain is quite distinct from that of 11-HSD1 mRNA and allows for diverse roles in modulating corticosteroid receptor involvement in control of salt appetite, blood pressure and the hypothalamo-pituitary-adrenal axis.

Through determining the rate and speed of extracting and the contents of effective constituents, an experimental comparison was made of the new TCM-decoction with the traditional decoction. The result showed that the new one was better than the traditional one.

Human Pro-Urokinase (Pro-UK) is expressed in CHO-DHFR- cells at high efficiency by co-transfecting the mouse dhfr gene and Pro-UK cDNA under the control of the SV40 late promoter. After gene co-amplification, the product level could reach 2-3 micrograms/10(6) cells/24 h in the presence of 5 x 10(-6) mol/L MTX, and the levels can be further raised to 3.5-4 micrograms/10(6) cells/24 h by PMA superinduction. The copy number of Pro-UK cDNA in the genomes of host cells is about 200-300 copies/cell. The Western blot analysis shows that the recombinant Pro-UK has similar molecular weight to its natural counterpart, and also the amidolytic activity of the product is determined by S-2444 assay.

A unified theory of collective dislocation motion including both thermal activation and viscous drag effects is proposed. The theory is able to describe both fast and slow moving dislocation with a simple equation. The experimental dislocation velocity‐stress relation data of KCl crystals are fitted with the theory. Good consistency is obtained. The comparison of the theory with the classical theory of single dislocation is also given.

Experimental results of phase transition in InSb single crystal along the [111] direction under shock loading are presented. The recorded wave profiles show a two‐wave structure which is relateed to cubic‐orthorhombic transition. The determined transition stress is 1.73±0.11 GPa, which corresponds to a mean stress 0.95 GPa that is much lower than static data of 2.5 GPa. It demonstrates that the existence of a high shear stress does greatly decrease transition pressure for this material.

In this paper, we discuss a class of integrodifferential equations with nonlocal conditions via a fractional derivative of the type: \[\begin{aligned}D_{t}^{q}x(t)&=Ax(t)+\int\limits_{0}^{t}B(t-s)x(s)ds+t^{n}f\left(t,x(t)\right),&&t\in [0,T],\;n\in Z^{+},\\&&&q\in(0,1],\;x(0)=g(x)+x_{0}.\end{aligned}\] Some sufficient conditions for the existence of mild solutions for the above system are given. The main tools are the resolvent operators and fixed point theorems due to Banach's fixed point theorem, Krasnoselskii's fixed point theorem and Schaefer's fixed point theorem. At last, an example is given for demonstration.

Transcranial Doppler (TCD) was performed in 64 patients with subarachnoid hemorrhage (SAH) to detect the blood velocity in middle cerebral artery (MCA). Based on Poiseuille's principle, the increase of blood velocity was used as an indicator of cerebral vasospasm (CVS). It was found that 61.67% of the patients with SAH developed CVS, especially in the second week after SAH. The incidence of CVS in patients below 50 years old was higher than that in patients above 51 years old. The results showed that TCD is valuable in evaluation of CVS after SAH.

Expression vectors containing the pro-urokinase (pro-UK) cDNA (pSV2-proUK) and a dihydrofolate reductase cDNA (pSV2-dhfr or MMTV-dhfr) were cotransfected into CHO-dhfr- cells by the calcium phosphate precipitation technique. The dhfr+ transformants were selected by fibrinolytic agarose plate assay. Two colonies, named CLF-14 and CLF-8, exhibited significantly high expression levels of the biological activity of urokinase-type plasminogen activator (mu-Pa). They reached more than 24 IU/10(6) cells/48 h and 16 IU/10(6) cells/48 h, respectively. Examination of the cell supernatants for mu-Pa antigenicity using ELISA method also showed strong positive results, and the quantities of expression were about 0.14-0.22 micrograms/10(6) cells/48 h and 0.08-0.14 micrograms/10(6) cells/48 h, respectively. The mu-Pa secreted by stable transformed cells could be completely inhibited by UK anti-serum, but not by tissue-type plasminogen activator (t-PA) antiserum nor by normal rabbit serum.

Seven cases of ovarian sex cord tumor with annular tubules are reported in this paper. All lesions occurred in the young (6-25 years of age with a mean of 15 years) without Poutz-Jeghers syndrome. Four cases had estrogenic hormonal imbalance and abdominal mass. Gross examination revealed that the tumors were unilateral with smooth surface. Except one, all showed varying degrees of cystic degeneration on section. The sections appeared as roe-like granular substance in a pale yellowish brown shade in the parenchymal region. Microscopic examination showed single or complex annular tubules with prominent basement membrane-like material around the tubules. Lipid in the cytoplasm and granulosa cell tumor-like differentiation were observed in isolated area of some cases. Ultrastructurally, Charcot-Battcher filaments were found in 1 case, indicating differentiation towards Sertoli's cells. The malignant potential of this tumor had been elucidated in the literature.

The differences of serum lipid and lipoprotein (LP, profiles of animals susceptible (rabbit) and nonsusceptible (Beijing duck) to atherosclerosis as well as the distribution of apolipoprotein (apo) A-I and its catabolism in vivo were studied. Eight items, i.e. total cholesterol (TC), high density lipoprotein (HDL) cholesterol, triglyceride, percentage of alpha-LP and beta-LP, beta-LP concentration, lecithin cholesterol acyl transferase (LCAT), and agarose and polyacrylamide gel electrophoresis of both species were assayed before and after feeding a high fat, high cholesterol diet. Results indicate that the exogenous cholesterol consumed by Beijing ducks was carried and transported by HDL, while that in rabbits was transported by low density lipoprotein (LDL). The biological half lives of apo A-I in serum and in HDL were 41.1 +/- 2.4 and 42.8 +/- 1.7 h respectively, and its distribution in different organs was in the order of liver greater than kidney greater than spleen greater than lung greater than heart greater than intestine greater than muscles greater than aorta. These results show that the liver is the major organ for metabolizing HDL apo A-I, and the kidney is also important. The results also imply that in Beijing ducks the cholesterol carried by HDL may be catabolized through apo A-I receptors in the liver and kidney. The differences in cholesterol binding and in lipoprotein and apolipoprotein metabolism of the two species provide important clues for the elucidation of the pathogenesis of atherosclerosis.

After its identification by Evans and Nason (1953), nitrate reductase (NR) was shown to be a substrate inducible enzyme by Tang and Wu (1957). In 1960 Hageman and Flesher demonstrated further that both light and NO3 − were required for the appearance of nitrate reductase activity (Hageman and Flesher 1960). Since that time there have been many reports confirming the initial observations with light and NO3 − and conflicting reports concerning the repression of the induction of NR by NH4 + (Beevers and Hageman 1972; Ullrich 1987).

An axisymmetric capsule, consisting of an incompressible liquid droplet, surrounded by an infinitely thin elastic membrane having a Mooney constitutive behaviour, is suspended into another incompressible Newtonian liquid subjected to an elongational shear flow. The motion and the deformation of the capsule are determined numerically by means of a boundary-integral technique. It is thus possible to reach large deformations, and to study the influence of the initial geometry of the particle, as well as that of the constitutive behaviour of the membrane. In all cases considered here, it appears that there exists a critical value of the non-dimensional shear rate (the capillary number) above which no steady solution can be obtained, and where the capsule continuously deforms. This phenomenon is interpreted as the outset of burst. The model shows also the importance of the sphericity index for the determination of the overall capsule deformability.

Using the57Fe Mossbauer effect the influence of the Ga content in amorphous (Fe1−xGax)84B16 on the average hyperfine fields\(\bar H\) and isomer shift has been studied. For the sample (Fe0.98Ga0.02)84B16 the\(\bar H\), as well as the recoilless fraction,fa were measured as functions of temperature ranging from 12 K to 300 K. The experimental results show a linear correlation between Infa and δ, and well as between δ andx. In the temperature range\(\bar H(T)\) can be described by the Brillouin function and the second-order Doppler shift is appreciable. The characteristic temperature for such an amorphous alloy is 372 K. the effective vibrating massMeff=79 a.u.

A decagonal quasicrystal with a periodicity of 1·6 nm along the tenfold axis, similar to that in Al─Pd and Al─Co, has been found in a rapidly solidified Al6Ni alloy containing a few per cent of silicon. In addition, a new decagonal phase has been found in Al4Ni which has a periodicity of 0·4 nm along the tenfold axis. This decagonal phase is different from those reported before in the aluminium–transition metal alloys. A new metastable crystalline phase Al9Ni2 having the structure of Al9Co2 has been found.

The silver-stained acrocentric chromosome association (Ag-AA) is the remnant of the nucleolus. Its frequency reflects the transcriptional activity of cellular rRNA genes.