Multistage Growth Research Articles

Multifocal pathomorphological study of bladder cancer with the use of luminescence analysis.

Operation material from patients with various forms of urinary bladder cancer was examined. Systemic involvement resulting from multistage and multifocal tumor growth due to previous multicentric changes was demonstrated. Fluorescent study showed that in urinary bladder cancer tumor transformation involves not only adjacent, but also distant mucosa.

In-situ trace element analyses and Pb-Pb dating of zircons in granulite from Huangtuling, Dabieshan by LAM-ICP-MS

It is revealed by CL images that there are multi-stage growth internal structures of zircons in the Huangtuling granulite, including the inherited zircons, protolith zircons, sector and planar zone zircons and retrograde zircons. In-situ trace element compositions and Pb-Pb ages have been analyzed by LAM-ICP-MS. The sector and the planar zone domains show typical trace element characteristics of granulite zircon (low Th, U, Th/U, total REEs, clear negative Eu anomalies, relatively depleted HREE and small differential degree between MREE and HREE, etc.), indicating that they formed during granulite-facies metamorphism. The protolith zircons have trace element characteristics of crustal zircon (high Th, U, Th/U, total REEs and enriched HREEs, etc.). 12 analyzed spots on granulite-facies domains give a weighted mean 207Pb/206Pb age of (2154±26) Ma (MSWD = 3.8), which is the best estimated age of granulite-facies metamorphism of this sample. The weighted mean 207Pb/206Pb age of 5 analyzed spots on protolith zircon domains is (2714 ± 22) Ma (MSWD = 1.4), which represents the protolith forming time. The discovery of ca. 3.4 Ga inherited zircon indicates that there are Palaeoarchean continental materials in this area. The interpretation of formation conditions and the ages of zircons can be constrained by simultaneous in-situ analysis of trace elements and ages.

Major element composition of the lithospheric mantle under the North Atlantic craton: Evidence from peridotite xenoliths of the Sarfartoq area, southwestern Greenland

The composition and thermal state of the lithospheric mantle under the North Atlantic craton was investigated using a suite of peridotite xenoliths from the diamond-bearing Sarfartoq kimberlite dike swarm of southwestern Greenland. Elevated olivine and whole-rock Mg# (>0.9) attest to the refractory nature of the Sarfartoq mantle showing comparable degrees of depletion to other cratonic roots. Modal analyses indicate that the Sarfartoq mantle is not typified by the orthopyroxene enrichment observed in the Kaapvaal root, but shows more affinity with the Canadian Arctic (Somerset Island), Tanzania, and East Greenland (Wiedemann Fjord) peridotites. The Sarfartoq peridotites have equilibrated at temperatures and pressures ranging from 660 to 1,280 °C and from 2.2 to 6.3 GPa, and define a relatively low mantle heat flow of 13.2±1 mW/m2. In addition, the lithospheric mantle underneath the Sarfartoq area is compositionally layered as follows: (1) an internally stratified upper layer (70 to 180 km) consisting of coarse, un-deformed, refractory garnet-bearing and garnet-free peridotites and, (2) a lower layer (180 to 225 km) characterized by fertile, CPX-bearing, porphyroclastic garnet lherzolites. The stratification observed in the upper refractory harzburgite layer (70–180 km) is reflected by an increase in fertility (e.g., decrease in olivine abundance and forsterite content) with depth. The sharp nature of the boundary between the upper and lower layers may indicate multistage growth of the lithospheric mantle.

The Hot Corrosion of Fe-Mn-Al–C Alloy with NaCl/Na 2 SO 4 Coating Mixtures at 750°C

The high-temperature corrosion behavior of Fe-30.1Mn-9.7Al-0.77C alloy initially coated with 2 mg/cm2 NaCl/Na2SO4 (100/0, 75/25, 50/50, 25/75 and 0/100 wt.%) deposits has been studied at 750°C in air. The result shows that weight-gain kinetics in simple oxidation reveals a steady-state parabolic rate law after 3 hr, while the kinetics with salt deposits all display multi-stage growth rates. The corrosion morphology of the alloy with 100% Na2SO4 coating is similar to that of simple oxidation. NaCl acts as the predominant corrosion species for Fe-Mn-Al-C alloy, inhibiting the formation of a protective oxide scale. For the alloy coated with over 50% NaCl in salts, NaCl induces selective oxidation of manganese and results in the formation of secondary ferrite in the alloy substrate as well as void-layers with different densities of voids layer by layer in the secondary-ferrite zone.

Diagenetic trends of fluorine concentration in Negev phosphorites, Israel: implications for carbonate fluorapatite composition during phosphogenesis

An electron probe and chemical study of bulk phosphorite samples and separated constituents from various Negev deposits was carried out together with XRD, FTIR spectroscopy and textural analysis. The results allow a better understanding of the distribution of fluorine in these Upper Cretaceous phosphorite sequences and shed light on variations in the composition of the carbonate fluorapatite (CFA) phase during phosphogenesis. Two facies are recognized: (1) a pristine, microbially generated phosphorite facies; (2) a recycled, peloidal and biodetrital facies. Fluorine distribution in the Negev phosphorites is facies controlled: F/P2O5 is much lower in the pristine facies (0·090–0·107) than in the recycled facies (0·107–0·120). In addition, F/P2O5 varies considerably between the various constituents of the phosphate fraction; F‐poor francolites (F/P2O5 as low as 0·080) co‐exist with F‐rich francolites (F/P2O5 as high as 0·135) in the same phosphorite bulk sample. A lower F/P2O5 in francolite is associated with higher Cd and Zn concentrations in the phosphorite, an increase in Fe‐rich smectites in the clay fraction and the presence of structural OH in the francolite. The lower F/P2O5 ratios in the pristine facies are attributed to high organic deposition rates during the formation of these matted sediments, leading to rapid burial of the in situ‐forming CFA. This is possibly coupled with diffusion of F from sea water into bottom sediments being hampered by microbial mat coatings. These conditions resulted in O2‐depleted porefluids, inducing the precipitation of Cd‐rich Zn sulphides and the formation of Fe‐rich smectites. F‐enrichment probably takes place when the earlier formed F‐poor ‘primary’ CFA is relocated close to the sea floor and bathed with interstitial sea water solutions of higher F concentrations. Oxidation and removal of the sulphide‐bound Cd and Zn apparently occurred together with enrichment in F of the francolite. Combining chemical data with XRD and FTIR results suggests a multistage growth for the Negev phosphate constituents in shifting formational sites and porefluids of varying F concentrations. This multiphase growth is reflected in the patchy distribution of F in the Negev constituents and might explain the inverse correlation between mean CO2/F and F/P2O5 ratios of the analysed phosphorites in the two facies. It also suggests that CFA (or an amorphous precursor) initially formed with some OH groups in the apatite structure, which were subsequently substituted by F ions in recycled francolite through re‐equilibration with porefluids of higher F concentrations.

CL and FTIR analysis on the diamonds in Wafangdian, Liaoning Province

The CL images show that the internal structures of the diamonds in Wafangdian, Liaoning Province is classified as three types: simple growth girdle zone, multi-stage growth complex girdle zone, and rare agate-like structure. These internal features reflect the complexity of growth processes of the diamonds. The FTIR analyses in micro area on diamond plates reveal the heterogeneity of the impurities of nitrogen and hydrogen. The variety of nitrogen contents and nitrogen aggregation states have been revealed not only in different diamonds from one kimberlite pipe but also in different zones of one diamond. The extent of conversion A defects to the aggregated B form is a function of the nitrogen aggregation temperature (T NA), mantle residence time (t MR), and nitrogen concentration of diamond. The interval of 0.6–0.7Ga from core to rim of diamond growth is obtained by using the FTIR curves and some geological data. The long period of diamond growth is identical with the feature in CL image.

Prediction of multicomponent inorganic atmospheric aerosol behavior

Many existing models calculate the composition of the atmospheric aerosol system by solving a set of algebraic equations based on reversible reactions derived from thermodynamic equilibrium. Some models rely on an a priori knowledge of the presence of components in certain relative humidity regimes, and often fail to accurately predict deliquescence point depression and multistage aerosol growth. The present approach, relying on adjusted thermodynamic parameters of solid salts and a state of the art activity coefficient model, directly minimizes the Gibbs free energy (according to thermodynamic equilibrium principles) given temperature, relative humidity and the total (gas plus aerosol) ammonia, nitric acid, sulfate, sodium, and hydrochloric acid concentrations. A direct minimization, while requiring no additional assumptions in its algorithm, allows the elimination of many of the assumptions used in previous models such as divided relative humidity (rh) and composition domains where only certain reactions are assumed to occur and constant DRH values despite varying temperature and composition. Moreover, the current approach predicts aerosol deliquescence and efflorescence behavior explaining the existence of supersaturated aerosol solutions. A comparison is conducted between our approach and available experimental results under several conditions. The current model agrees with experimental results for single salt systems although it shows sensitivity to thermodynamic parameters used in the minimization algorithm. A set of Δ G 0 f for solid salts is estimated that is consistent with available laboratory measurements and significantly improves model performance. For multicomponent systems, the current approach with adjusted Δ G 0 f accurately reproduces observed multistage growth patterns and deliquescence point depression over a broad temperature range. Finally, the direct Gibbs free energy minimization accurately reproduces aerosol efflorescence behavior.

Cryptic crustal events elucidated through zone imaging and ion microprobe studies of zircon, southern Appalachian Blue Ridge, North Carolina–Georgia

Compositional zoning reveals multistage growth histories and resorption events in zircon from a high-grade terrane in the eastern Blue Ridge of North Carolina and Georgia. These zoning patterns were used to guide high-resolution ion microprobe dating that places important constraints on the evolution of the southern Appalachian crust. Zircons from granulite facies metapelite have unzoned rims that yield concordant U-Pb ages of 495 ± 14 Ma. We interpret this as the time of rim growth, which occurred during peak metamorphism early in the protracted orogenic history of the region. Detrital cores, characterized by truncated euhedral zoning, are of Grenville age (1.04–1.26 Ga). Zircons from the Whiteside and Rabun plutons have well-defined, rounded, inherited cores and euhedral, oscillatory-zoned magmatic rims. Rims of Rabun zircons record magmatic crystallization at 374 ± 4 Ma, whereas Whiteside rims yield a 466 ± 10 Ma crystallization age. Cores from both plutons include 1.1–1.3 Ga and 2.6–2.7 Ga ages. These data indicate that there was no single, voluminous episode of plutonism in this area, that similar material underpinned the region at least from 370 to 470 Ma, and that previously unrecognized Archean basement or Archean basement–derived sedimentary rock was present in the southern Appalachians. Results of this study verify the value of combining zoning and ion microprobe studies: Using conventional U-Pb methods or ion microprobe dating without knowledge of zoning would have made interpreting the events recorded in these zircons and the ages that they yield difficult or impossible.

Growth history of two garnet porphy rob lasts of the Cima Dura- Durreck Complex and its implication on the polymetamorphic evolution of this complex (Austrides, Eastern Alps)

Detailed microstructural and microprobe analyses were carried out on some small garnet idioblasts from phyllonites and two garnet porphyroblasts, respectively from a representative amphibolite and phyllonite rock sample. A consistent sequence of growth stages has been ascertained in this way in the two porphyroblasts, suggesting, combined with the structural reasoning, that their multistage growth is entirely pre-Alpine in both cases. The results discussed in the present paper indicate that, as the amphibolite lithons are related to deformation partitioning on the mesoscale, the persistence of Variscan garnet porphyroblast in the phyllonites is due to deformation partitioning on the microscale.

Fractal properties of flocs formed by fluid shear and differential settling

The fractal properties of fine-grained sediment flocs formed by fluid shear and by differential settling were studied through floc porosity–size relationships. Flocs were produced from flocculation tests in a Couette-type flocculator in which fluid shear was the dominant collision mechanism for flocculation, and in a disk-type flocculator in which differential settling was the dominant collision mechanism. Floc samples were then introduced into a settling tube to measure their sizes and settling speeds by a double-exposure photographic method. The porosities of flocs were determined from the settling speed data using a porous sphere settling model. It was found that the flocs produced in the Couette-type flocculator could be regarded as fractals, with a fractal dimension ranging from 1.83 to 1.97. However, the flocs produced in the disk-type flocculator did not exhibit simple scaling behavior and could not be regarded as fractals. The differences in fractal property are due to the differences in floc formation schemes associated with the collision mechanisms. The similarities between experimentally obtained flocs and computer simulated clusters are discussed. The multistage growth model, a formation scheme for flocs formed by fluid shear, is consistent with the cluster–cluster model used in computer simulations. A formation scheme for flocs formed by differential settling is postulated; it is consistent with the particle–cluster model used in computer simulations.

Transmission electron microscopy and scanning transmission electron microscope analysis of the effects of thermal processing on the structural integrity of GaInAs/GaInAsP multilayers

The structural characterization by electron microscopy of a metalorganic chemical vapor deposition grown GaInAs/GaInAsP multiple-quantum-well structure undergoing a ‘‘blue shift’’ in luminescence wavelength upon thermal processing, as part of a multistage epitaxial growth process, is reported. The sample exhibits a shift toward shorter wavelengths of greater than 100 nm upon annealing at 750 °C. The structural modifications that result in the blue shift include an elimination of atomic ordering in the quaternary barrier layers of the material, and significant layer interdiffusion. A method is described whereby quantitative analyses of the layer composition and lattice parameter with a spatial resolution better than 2 nm can be obtained from semiconductor multilayers using energy-dispersive x-ray microanalysis in the scanning transmission electron microscope. Such an analysis shows that the interdiffusion occurs along a nonlinear (that is, nonlattice matched) path where the group-V element diffusivities exceed those of the group-III elements, and results in the incorporation of excess coherency strains of up to 0.5% in the quantum-well regions.

The functions of technology infrastructure in a competitive economy

Governments of industrialized nations play varied but important roles in providing the diverse technology infrastructure that supports a modern, competitive economy. An understanding of the structure and impacts of these roles as well as efficiency differences among alternative implementation schemes is particularly important at this time as competing industrialized nations are revamping their technology infrastructures in response to major shifts in the scope as well as the content of their growth strategies. These shifts in scope can be described as evolutionary changes from single-stage to multi-stage strategies, in that several modes of technology-based competition are simultaneously pursued. That is, whereas an economy may have focused on innovation, manufacturing, high-volume or niche markets, etc. most if not all of these must be pursued together in the future in order to diversify risk and achieve economies of scope. Effective implementation of the more complex multi-stage growth strategy requires a consensus model of the appropriate functions for infrastructure and its institutions. Such a consensus model is necessary to efficiently guide strategic planning in both industry and government. In particular, a conceptual basis is needed for defining the critical interfaces between the government and industry roles, including effective long-range planning, communication, and cooperation. The required technology infrastructure policy model is derived from a microeconomic model of the typical technology-based industry. Existing national strategies have demonstrated the importance of efficiency at the production and market development stages as well as at the R&D stage, but the trend is towards promoting simultaneous efficiency at all these stages. That is, the model and the derived infrastructure functions must cover all stages and interfaces in the technology and related product life cycles.

A Multistage History for Flin Flon Lead

New analyses are presented to show a multistage evolutionary growth for lead from the Flin Flon, Manitoba area. A first order interpretation suggests a very ancient separation of lead from a homogeneous source region. All single-stage interpretations of lead isotope data must be made with utmost caution.