Black Droplets Research Articles

Black funnels and droplets from the AdS C-metrics

We recently argued that the dynamics of strongly coupled field theories in black hole backgrounds is related via the AdS/CFT correspondence to two new classes of AdS black hole solutions: black funnels and black droplets suspended above a second disconnected horizon. The funnel solutions are dual to black holes coupling strongly to a field theory plasma. In contrast, the droplet solutions describe black holes coupling only weakly. We continue our investigation of these solutions and construct a wide variety of examples from the AdS C-metric in four bulk spacetime dimensions. The solutions we find are dual to field theories on spatially compact universes with Killing horizons.

Initiation and development of resin ducts in the major organs of Pinus massoniana

The structure, distribution and patterns of resin ducts in processes of its initiation and development were studied with the methods of thin section and ultrathin section. This paper emphasized the ultrastructural changes during canal development by a ring of the live epithelial cells, and the epithelial cells were usually surrounded with one or two layered sheath cells, which were normal parenchyma cells in some primary resin ducts and became dead cells with thick walls in other primary and secondary resin ducts. The resin ducts were found to occur in almost all organs, except in cotyledon. The resin ducts were formed by schizogeny and their development can be divided into three stages (e.g., initial stage, formation stage and mature stage). At the initial stage, the initial cells had many plastids without integral membrane structures, which contain one or two starch grains in them, and there are a few black osmiophilic droplets on the endoplasmic reticulum and membranes. A small number of osmiophilic droplets were present in the plastids. At the formation stage, the number of plastids, mitochondria and Golgi bodies in epithelial cells increased. The plastids were commonly surrounded by endoplasmic reticulum sheath. The larger osmiophilic droplets in cytoplasm and the smaller osmiophilic droplets on the plastids envelope, mitochondrion envelope and Golgi vesicles obviously increased in number during canal developing. At the mature stage, the cytoplasm of epithelial cells became thin with small nucleus. The number of mitochondria and Golgi body decreased, but numerous plastids still existed. Osmiophilic droplets were abundant in epithelial cells as in previous status. Taken together, the structures of plastids in epithelial cells gradually became well developed and the synthesis of resin was remarkably enhanced during resin duct formation and plastids should be the main site for resin synthesis.

Enhanced expression of chitinase during the autolysis of mushroom in Coprinellus congregatus

Fungal cell walls consist of various glucans and chitin. An inky cap, Coprinellus congregates, produced mushrooms at 25 degrees C in a regime of 15 h light/9 h dark, and then the mushroom was autolyzed rapidly to generate black liquid droplets where no cell wall was detected by microscopy. A chitinase cDNA from the matured mushroom cells of C. congregates that consisted of 1,541 nucleotides was successfully cloned using the rapid amplification of cDNA ends (RACE)-PCR technique. Its deduced 441 amino acid sequence had the conserved catalytic domain as in other fungal chitinase family 18. Chitinase activity was higher at the matured mushroom stage than primordial and young mushroom stage. When the expression of the cloned chitinase was examined by real-time PCR using the chitinase-specific primers, it was increased more than twice to 20 times during the autolytic process of mushroom than young mushroom or primordial stages, respectively.

Heating and evaporation of semi-transparent diesel fuel droplets in the presence of thermal radiation

Absorption and scattering spectral efficiency factors for spherical semi-transparent fuel droplets are approximated by simple analytical expressions as functions of imaginary and real parts of the complex index of refraction and the diffraction parameters of droplets. These expressions are applied to the modelling of thermal radiation transfer in Diesel engines. On the basis of the P-1 approximation, which is applicable due to the large optical thickness of combustion products, various ways of spectral averaging for absorption and scattering coefficients are suggested. Assuming that the concentration of fuel droplets is small, the scattering effects are ignored and the analysis is focused on approximations for the absorption coefficient. The average absorption coefficient of droplets is shown to be proportional to ar d 2+ b , where r d is the droplet radii, and a and b are quadratic functions of gas temperature. Explicit expressions for a and b are derived for diesel fuel droplets in the range 5–50 μm and gas temperatures in the range 1000–3000 K. The expression for the average absorption coefficient of droplets is implemented into the research version of VECTIS CFD code of Ricardo Consulting Engineers. The effect of thermal radiation on heating and evaporation of semi-transparent diesel fuel droplets is shown to be considerably smaller when compared with the case of black opaque droplets.

Fungal attack on coal II. Solubilization of low-rank coal by filamentous fungi

The solubilization of low-rank coal by fungi is not accompanied by its depolymerization, which was proven by several screening programs. A total number of 728 fungal strains were yet tested for solubilizing a German low-rank coal (lignite). The coal were used oxidatively pretreated (3% H 2O 2) and natively. During the first screening, the nitrogen content of the media were reduced to select fungi, which solubilize coal under nitrogen-limited conditions. Among 480 micromycetous fungi tested, at least ten strains were able to solubilize native low-rank coal pieces on a nitrogen-reduced agar-medium. They all belong to the conidiospores forming deuteromycetes (molds). Under ‘solubilizing’ conditions, only two of these ten strains showed weak extracellular activities (oxidases, peroxidases) toward 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonate) [ABTS]. In a second screening, 256 wood and litter decaying basidiomycetes, above all white-rot fungi, were tested for their ability to solubilize low-rank coal under ligninolytic conditions: not any strain was able to form black coal droplets or conspicuous diffusion areas. By using a nitrogen-rich medium, a few basidiomycetes showed also coal solubilizing activities, however, their ligninolytic enzymes were inhibited. The ‘typical’ solubilization of low-rank coal (formation of black liquids from solid coal particles) by molds depends mainly on the nitrogen content of the medium (resulting in higher pH values) as well as on the oxidation grade of coal (e.g. H 2O 2-pretreatment). Extracellular oxidases and peroxidases, both ligninolytic and nonligninolytic ones, seem to play a minor, (or not any), role for this process.

Light and Electron Microscopic Localization of Lipids in <italic>Blastocystis hominis</italic>

Localization of the lipid of Blastocystis hominis was histochemically demonstrated. B. hominis was fixed with glutaraldehyde, treated with detergents, and stained with Sudan black B or Nile blue. The central vacuole of B. hominis stained with Sudan black B showed many black droplets with great variation in staining intensity. In Nile blue staining, the central vacuole showed many pinkish granules or homogeneous blue reactions. These results indicated the presence of neutral lipids and/or acidic lipids in the central vacuole. At the ultrastructural level, the central vacuole and some cytoplasmic vesicles showed enhanced electron density after post-fixation with imidazole-buffered osmium tetroxide solution. Great variation in the density and distribution of the electron-dense materials was observed in the central vacuole. Since the electron-dense vesicles were frequently observed in the cytoplasm, B. hominis may accumulate the lipid in the central vacuole, the function of which is not well known.

Sulphur content and sulphur isotope composition of orange and black glasses in Apollo 17 drive tube 74002/1

The sulphur contents and δ 34 S values have been determined for the bulk and various grain size fractions of three 74002 1 lunar drive tube samples. The sulphur contents of the bulk samples ate much lower than those of other lunar soils. These samples, along with the surface orange soil 74220 analysed previously, show an increase of sulphur concentration with decreasing particle size which is more marked than for other soils and indicates that the orange and black glass droplets have a coating enriched in sulphur and other volatile elements. In sharp contrast with other soils, the orange and black glasses have slight positive δ 34 S values for large particles while the smallest particle sizes show negative δ 34 S values. This indicates that the coating of the glassy droplets is enriched in isotopically light sulphur. These observations favour the theory that the orange and black glasses were generated by a volcanic fire fountain. The anomalously high δ 34 S values of the fine fractions of the core bottom sample, 74001-135, combined with the results of an acid leaching experiment, indicate that these fractions are contaminated, possibly by a mature soil of high sulphur content and relatively positive δ 34 S value.

Juvenile Type of Generalized Ceroid-Lipofuscinosis (Spielmeyer-Sjögren Syndrome) – II. Biopsy findings

Rectal biopsies were obtained from 11 children, clinically presumed to suffer from the juvenile type of generalized ceroid-lipofuscinosis. In addition, sural nerve biopsies were performed in 4 cases. Of the various staining procedures applied for light microscopy, Sundan Black B was found to be the most useful, revealing in each of the rectal biopsies at least some nerve cells with coarse black droplets as well as numerous mucosal macrophages with a more greyish, dustlike material. In sural nerve biopsies a slight reduction of the thick myelinated nerve fibers was seen in two cases, accompanied by regeneration phenomena. The latter were also detectable in one other case, the remaining sural nerve biopsy being histologically unremarkable. By electron microscopy neuronal perikarya revealed lipopigment bodies with a fingerprint-like pattern in each of the rectal biopsies. In one case only was this pattern combined with distinct curvilinear profiles. In 4 cases, however, the fingerprint-like deposits were intermingled with different lamellated bodies, some of them reminiscent of MCB's or zebra bodies. In two of the 4 cases, these were even seen exclusively in some neurons. In each of the rectal as well as the sural nerve biopsies, most of the non-neuronal cell types presented lipopigment bodies, likewise, displaying both curvilinear and fingerpring-like profiles, with some characteristics related to the various cell types. With regard to generalized ceroid-lipofuscinosis the diagnostic value of rectal biopsies, though being disputed in the literature, appears reestablished by the findings presented.