Brownish Tint Research Articles

Investigating the processes and rate of iodide ion and compound oxidation in subterranean hydrothermal waters

Studies using physico-chemical methods have been conducted to evaluate the oxidative characteristics of various reagents for the technological extraction of iodine from groundwater and sufficient data have been obtained. According to the research results, iodine is predominantly present in the form of molecular iodine (85.6%), iodide ions (3.2%), iodate (9.1%) and iodine chloride (2.1%) were detected. Preserving all forms of iodine in solution at the same time is possible only in an alkaline environment, where the oxidizing properties of iodates are sharply reduced. This information is important for choosing a method for purifying iodine paste using various physical and chemical methods. From experiments in research, the beginning of the release of elemental iodine was noted at a voltage above 0.250 V and a pH of 5-3 or less. In this case, the solution usually becomes dark red with a reddish or brownish tint, which indicates the formation of complex compounds of iodine with other ions in the solution.

Botuobinskite and mirnyite, two new minerals of the crichtonite group included in Cr-pyrope xenocrysts from the Internatsionalnaya kimberlite

AbstractTwo new mineral species of the crichtonite group: botuobinskite, ideally SrFe2+(Ti4+12Cr3+6)Mg2[O36(OH)2] and mirnyite, ideally SrZr(Ti4+12Cr3+6)Mg2O38, occur as inclusions in mantle-derived Cr-pyrope xenocrysts from the Internatsionalnaya kimberlite pipe, Mirny field, Siberian craton. Botuobinskite forms needle- and blade-like acicular crystals up to 1 mm in length and up to 30 μm in diameter, a large platy inclusion (700 × 700 × 80 μm) and roughly isometric grains (up to 80 μm). Mirnyite occurs as needle-and blade-like elongated inclusions (up to 1 mm). Both minerals are jet-black, opaque and exhibit a metallic lustre. In plane-polarised reflected light, botuobinskite and mirnyite are greyish-white with a weak brownish tint. Between crossed polars, the new species show distinct anisotropy in shades of bluish grey to greenish-brown. Neither bireflectance nor pleochroism is observed. Calculated densities for botuobinskite and mirnyite are 4.3582(5) and 4.3867(3) gm/cm3, respectively. The crystal structures of botuobinskite and mirnyite have been refined (R = 0.0316 and 0.0285, respectively) from single crystal X-ray diffraction data. The minerals are trigonal, crystallise in the space group R$\bar{3}$ (No. 148) and are isostructural with other members of the crichtonite group. The unit cell parameters are a = 10.3644(8) Å, c = 20.6588(11) Å and V = 1921.9(2) Å3 for botuobinskite and a = 10.3734(8) Å, c = 20.6910 (12) Å and V = 1928.2(2) Å3 for mirnyite, with Z = 3 for both. The Raman spectra of the minerals show strong peaks at 133, 313 and 711 cm–1. Infrared spectroscopy data for botuobinskite indicates H–O stretching of the hydroxyl groups. Botuobinskite and mirnyite have been approved by the IMA–CNMNC under the numbers 2018-143a and 2018-144a, respectively. Botuobinskite and mirnyite are named after the Botuobinskaya exploration expedition and Mirny town, respectively. The minerals may be considered as crystal-chemical analogues of other crichtonite-group species occurring in the lithospheric mantle (i.e. loveringite, lindsleyite and mathiasite). Both species commonly occur in intimate association with Cr-pyrope as well as other peridotitic minerals and exert an important control on the partitioning of incompatible elements during mantle metasomatism.

Horseradish Peroxidase-Catalyzed Coloration of Natural Phenols on Silk Fabric: Effects of Various Buffer Systems and pH Value on Dyed Color

ABSTRACT Currently, the known possible shades obtained for coloring silk fabrics using enzyme catalysts such as peroxidase are limited to a few shades of brownish tint. For the oxidative dyeing method using horseradish peroxidase (HRP) to become common, it must be able to produce a more diverse range of colors; this is a problem that must be solved. The purpose of this study is to obtain various colors by dyeing natural phenolic substrates using HRP in various buffers (acetate, citrate, phosphate buffer) and various pH levels (3 ~ 9). We emphasized color diversity, which was achieved through the exploration of six different natural aromatic compounds: gallic acid (GA), guaiacol (GAC), p-coumalic acid (CA), ferulic acid (FA), catechol (CAC) and caffeic acid (CFA). We also performed a methodological survey of reaction processing parameters. The colored products generated through HRP catalysis were analyzed using UV-vis. The color of the dyed fabrics was analyzed using the CIE L*a*b* color space system. As a result of the experiment, we obtained silk fabrics with various color depths from each buffer system. This suggests that the desired color and tone of dyed silk fabrics can be achieved by adjusting the buffer system and pH value.

Hrabákite, Ni9PbSbS8, a new member of the hauchecornite group from Příbram, Czech Republic

AbstractThe new mineral hrabákite (IMA2020-034) was found in siderite–sphalerite gangue with minor dolomite–ankerite at the dump of shaft No. 9, one of the mines in the abandoned Příbram uranium and base-metal district, central Bohemia, Czech Republic. Hrabákite is associated with Pb-rich tučekite, Hg-rich silver, stephanite, nickeline, millerite, gersdorffite, sphalerite and galena. The new mineral occurs as rare prismatic crystals up to 120 μm in size and allotriomorphic grains. Hrabákite is grey with a brownish tint. Mohs hardness isca. 5–6; the calculated density is 6.37 g.cm–3. In reflected light, hrabákite is grey with a brown hue. Bireflectance is weak and pleochroism was not observed. Anisotropy under crossed polars is very weak (brownish tints) to absent. Internal reflections were not observed. Reflectance values of hrabákite in air (Rmin–Rmax, %) are: 39.6–42.5 at 470 nm, 45.0–47.5 at 546 nm, 46.9–49.2 at 589 nm and 48.9–51.2 at 650 nm). The empirical formula for hrabákite, based on electron-microprobe analyses (n= 11), is (Ni8.91Co0.09Fe0.03)9.03(Pb0.94Hg0.04)0.98(Sb0.91As0.08)0.99S7.99. The ideal formula is Ni9PbSbS8, which requires Ni 47.44, Pb 18.60, Sb 10.93 and S 23.03, total of 100.00 wt.%. Hrabákite is tetragonal,P4/mmm,a= 7.3085(4),c= 5.3969(3) Å, withV= 288.27(3) Å3andZ= 1. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I)(hkl)] are: 3.6543(57)(200); 3.2685(68)(210); 2.7957(100)(211); 2.3920(87)(112); 2.3112(78)(310); 1.8663(74)(222); and 1.8083(71)(302). According to the single-crystal X-ray diffraction data (Rint= 0.0218), the unit cell of hrabákite is undoubtedly similar to the cell reported for tučekite. The structure contains four metal cation sites, two Sb (Sb1 dominated by Pb2+) and two Ni (with minor Co2+content) sites. The close similarity in metrics between hrabákite and tučekite is due to similar bond lengths of Pb–S and Sb–S pairs. Hrabákite is named after Josef Hrabák, the former professor of the Příbram Mining College.

Application of Luminescent Microscopy in Analysis of Anatomic-diagnostic Signs of Fruits of Sea Buckthorn

Introduction. Sea buckthorn (Hippophae rhamnoides), the family Eleagnaceae – a promising source of biologically active substances, the traditional raw materials of which are fruits. The existing regulatory documentation (ND) lacks such an indicator of the authenticity and good quality of the fruit as «microscopy». Despite the available data on the anatomy and histology of the fruits of this type of medicinal plant material (MPM), the scientific literature does not describe the luminescence features of the tissues of sea buckthorn fruit. It is known that the luminescent features of tissues make it possible to identify the localization of biologically active structures, and also, in some cases, to conduct selective diagnosis of MPM.Aim. The aim of this work was to study the characteristics of the luminescence of the tissues of dried crushed fruits of sea buckthorn, and also to optimize the conditions for analysis.Materials and methods. The object of the study was the dried, crushed fruits of sea buckthorn of various species. The study of microdiagnostic signs was carried out according to the State Pharmacopoeia of the XIV RF GPA.1.5.3.0003.15 «Technique of microscopic and microchemical studies of medicinal plant materials and herbal medicines». A stereomicroscopic study was carried out on a Biomed-6 microscope. The luminescence of sea buckthorn fruit tissues was examined using a luminescent microscope of the Micromed-3 Lum brand.Results and discussion. The most pronounced yellow glow is observed for the tissue of the pulp and epidermis of the fetus, which is associated with the highest content of fatty oil in these structures. Groups of phenolic compounds contained along with oil give a greenish tint to objects, while condensed tannins give a brownish tint. The plates that make up the corymbose hairs do not exhibit bright luminescence; a weak glow is characteristic of the joints of the hair platelets. The walls of stellate hairs have a faint greenish glow. Fragments of the actual fruit («sac») are brownish in color, without their own luminescence, as well as the seed peel. The embryo has its own greenish luminescence due to the presence of both a fatty oil and a complex of storage substances.Conclusion. The luminescent analysis of sea buckthorn fruits was carried out for the first time. The choice of a method for preparing the studied MPM for microscopic examination is experimentally substantiated. The luminescent analysis revealed the peculiarities of the glow of the tissues of the fruits of sea buckthorn. The main microdiagnostic signs of crushed dried sea buckthorn fruits and their biometric characteristics are specified. The analysis of the obtained data will allow us to further develop the section «Microscopic signs» for inclusion in the PA project on MPM, widely cultivated and used by the domestic pharmaceutical industry for the production of herbal medicines.

A Case Study of Recycled Poly(Lactic Acid) Contaminated with Petroleum-Based Thermoplastics Used in Packaging Application

This study was designed to evaluate properties of poly(lactic acid) (PLA) under the postulation that recycled PLA (rPLA) was contaminated with commodity thermoplastics during a typical density-based sorting. Change in clarity, mechanical, and thermal properties of the contaminated rPLA specimens were compared. Clarity of rPLA was reduced showing pale brownish tint when passing multiple processing. Contamination with either PP or HIPS just 1 phr caused rPLA to become opaque, which the transmittance percentage was decreased with respect to contamination content. Compared to pure PLA, the moduli of rPLA was reduced 2.6%. The moduli of rPLA was reduced 4.5-8.2% when contaminated with PP of 1-8 phr, and the moduli was reduced 1.4-4.1% when contaminated with HIPS of 1-8 phr. Elongation at break of PP-contaminated rPLA specimens was reduced with slight increase of impact strength. Elongation at break of HIPS-contaminated rPLA specimens was higher with higher HIPS content, and the impact strength was enhanced up to 64%.

Mineral CuFe2S4 from sulfide Copper–Nickel ores of the Lovnoozero deposit, Kola Peninsula

The unnamed mineral CuFe2S4 has been found from sulfide Cu–Ni ores of the Lovnoozero deposit in the Kola Peninsula, Russia. It occurs in norite composed of orthopyroxene (bronzite), Ca-rich plagioclase (66% An), pargasite, and phlogopite. The last two minerals are replaced by talc, chlorite and carbonates. Monoclinic pyrrhotite, pentlandite, chalcopyrite, and pyrite are associated ore minerals. Phase CuFe2S4 is enclosed predominantly in chalcopyrite, probably replacing it, and occurs in later carbonate veinlets together with redeposited sulfides. It is light yellow with a brownish tint and metallic luster. The Mohs hardness is 5–5.5; VHN 654 ± 86 kgs/mm2. Density (calc.) = 4.524 g/cm3. The mineral is anisotropic, internal reflections are absent. Reflectance values (λ, nm R′g and R′p %) are: 440 30.3 29.5, 500 43.7 42.8, 560 50.9 49.6, 620 52.4 51.2, 640 52.6 51.4, 680 52.8 51.6, 700 52.7 51.4. CuFe2S4 is monoclinic, a = 6.260(4), b = 5.39(1), c = 13.19(1) A, β = 94.88(7)°, V = 443(1) A3, Z = 4. The strongest reflections in the powder diffraction pattern are [d, A (I) (hkl)]: 4.150 (10) (012), 3.559 (4) (\(11\bar 2\) ), 3.020 (4) (\(10\bar 4\) ), 2.560 (3) (\(21\bar 2\)), 2.500 (3) (\(10\bar 5\)), 2.340 (3) (\(12\bar 2\)), 1.817 (3) (215), 1.489 (3) (402). The chemical composition is as follows, wt %: 20.44 Cu, 35.85 Fe, 0.65 Ni, 0.14 Co, 43.15 S, total is 100.23. The empirical formula calculated on the basis of 7 atoms is Cu0.969(Fe1.934Ni0.034Co0.007)1.975S4.056. According to its mode of occurrence, the mineral was formed as a result of low temperature processes involving metamorphic hydrothermal solutions.

Structural and physical properties of transparent conducting, amorphous Zn-doped SnO2 films

The structural and physical properties of conducting amorphous Zn-doped SnO2 (a-ZTO) films, prepared by pulsed laser deposition, were investigated as functions of oxygen deposition pressure (pO2), composition, and thermal annealing. X-ray scattering and X-ray absorption spectroscopy measurements reveal that at higher pO2, the a-ZTO films are highly transparent and have a structural framework similar to that found in crystalline (c-), rutile SnO2 in which the Sn4+ ion is octahedrally coordinated by 6 O2− ions. The Sn4+ ion in these films however has a coordination number (CN) smaller by 2%–3% than that in c-SnO2, indicating the presence of oxygen vacancies, which are the likely source of charge carriers. At lower pO2, the a-ZTO films show a brownish tint and contain some 4-fold coordinated Sn2+ ions. Under no circumstances is the CN around the Zn2+ ion larger than 4, and the Zn-O bond is shorter than the Sn-O bond by 0.07 Å. The addition of Zn has no impact on the electroneutrality but improves significantly the thermal stability of the films. Structural changes due to pO2, composition, and thermal annealing account well for the changes in the physical properties of a-ZTO films.

Effect of steaming on the colour change of softwoods

The heat treatment of softwood (i.e. spruce, pine, fir, and larch) may result in significant colour changes. During this study Scots pine and spruce samples were steamed and analysed for their altered hue and lightness. Treatments included: 0 to 22 days of steaming time at a temperature range of 70 to 100°C. The outcome included a variety of colours between the initial hues and brownish tint. These new colours are similar to that of aged furniture and indoor wooden structures. Consequently, properly steamed softwood may be used to repair historical artefacts and relic furniture. Besides restoration, steamed stocks are excellent sources for manufacture of periodical furniture, where the aged appearance has aesthetical value. Results however, indicated that steaming at a temperature above 90 ˚C has a bleaching effect, i.e. the coloured chemical components formed by moderate steaming may be removed. Furthermore, we observed a linear correlation between lightness and colour hue at all steaming times and temperatures.

Pseudolyonsite, Cu3(VO4)2, a new mineral species from the Tolbachik volcano, Kamchatka Peninsula, Russia

Pseudolyonsite, ideally Cu 3 (VO 4 ) 2 , is a new mineral from the medium-temperature fumaroles of the New Tolbachik scoria cones, Tolbachik volcano, Kamchatka Peninsula, Russia. It occurs as needles that are 5–20 μm across and up to 0.5 mm in the length, which sometimes produce parallel intergrowths, sprays or openwork clusters up to 2 mm. Associated minerals are: piypite, hematite, magnetite, lyonsite, aphthitalite, palmierite, langbeinite, filatovite, lammerite, vergasovaite, rutile and native gold. Pseudolyonsite is dark red with a brownish tint to black, translucent to opaque, with a reddish-brown streak and adamantine to semi-metallic lustre. The mineral is brittle, but thin long needles are flexible. The fracture is conchoidal, and no cleavage was observed. The calculated density is 4.749 g/cm 3 . In reflected light in air the mineral is grey with a weak bluish tint, non-pleochroic, has distinct anisotropy and ubiquitous red to orange internal reflections. The reflectance values (R 1 and R 2 , %) in air for the four COM wavelengths are, respectively, 17.05, 19.6 (470 nm); 16.1, 18.15 (546 nm); 15.85, 17.7 (589 nm); and 15.55, 17.4 (650 nm). Four electron probe (EDS) analyses produced the following mean values: V 2 O 5 40.37, CuO 48.83, ZnO 7.60, MoO 3 1.89, and SiO 2 0.14, total 98.83 wt%, which corresponds, on the basis of 8 O atoms, to (Cu 2.58 Zn 0.44 ) ∑3.02 (V 1.88 Mo 0.06 Si 0.02 ) ∑1.96 O 8 . The idealised formula is Cu 3 (VO 4 ) 2 . Pseudolyonsite is monoclinic: P 2 1 / c , a = 6.2695(4), b = 8.0195(3), c = 6.3620(3) A, β = 111.96(1)°, V = 296.66(3) A 3 , Z = 2. The strongest powder X-ray diffraction lines [ d in A (I) ( hkl )] are: 4.70 (60) (110); 3.30 (79) (021, 120); 3.22 (87) (111); 3.18 (34) (−121, −102); 2.894 (74) (200, −211); 2.761 (100) (012); 2.479 (59) (−212, −122); 2.419 (67) (031, 130). The crystal structure was solved from single-crystal data and refined to R = 0.0444. Pseudolyonsite is isostructural with synthetic monoclinic Cu 3 (VO 4 ) 2 . The crystal structure of pseudolyonsite contains corrugated octahedral layers formed by the chains of edge-shared, distorted Cu(2)-octahedra running along the c axis and connected to each other by distorted Cu(1)-octahedra. The octahedra of both types contain Cu and subordinate Zn, and they are typically Jahn-Teller-distorted. Adjacent octahedral layers are connected to each other by VO 4 tetrahedra. Pseudolyonsite is dimorphous with triclinic mcbirneyite. The name pseudolyonsite comes from its close visual similarity to another vanadate mineral, lyonsite, Cu 3 Fe 3+ 4 (VO 4 ) 6 . Both the mineral and its name have been approved by the IMA CNMNC (IMA No. 2009-062).

MINERALOGICAL DATA ON ANGELAITE, Cu2AgPbBiS4, FROM THE LOS MANANTIALES DISTRICT, CHUBUT, ARGENTINA

Angelaite, ideally Cu2AgPbBiS4, occurs as a hypogene mineral in polymetallic ores at the Angela groups of veins in the mining district of Los Manantiales, in the province of Chubut, Argentina. The new mineral species is predominantly associated with pyrite, sphalerite, chalcopyrite, hematite, native gold and galena; less common associates are aikinite, wittichenite, miharaite and cervelleite. Angelaite forms subhedral, commonly oriented inclusions in galena; these may attain a size of up to 200 x 50 mm. The mineral is grey in color with a brownish tint, opaque, and lacks internal reflections. It has a metallic luster and a dark grey streak. The VHN10 ranges between 245 and 263 kg/mm(3) (mean 253), corresponding to a Mohs hardness of 3 1/2. In plane-polarized light, it is strongly bireflectant and pleochroic from light grey with a brownish tint to light cream with a greenish tint. Angelaite is strongly anisotropic, with rotation tints in shades of pale grey, deep green and deep blue. We provide the measured values of reflectance in air and oil. The average of 23 electron-microprobe analyses is: Cu 16.7(3), Ag 13.4(2), Pb 27.8(6), Bi 26.6(5), S 16.0(2), total 100.5(5) wt.%, equivalent to Cu2.07Ag0.97Pb1.05Bi1.00S3.91. The ideal formula (on the basis of nine atoms) is Cu2AgPbBiS4, which requires Cu 16.31, Ag 13.84, Pb 26.58, Bi 26.81, S 16.45, total 100 wt.%. Angelaite is orthorhombic, with a 12.734(5), b 4.032(1), c 14.633(5) angstrom, V 751.8(5) angstrom(3), space group Pnma and Z = 4. The calculated density is 6.934 g/cm(3). It is a homeotype of galenobismutite, with Cu and Ag replacing one of the Bi positions in a complicated way. The strongest eight lines in the calculated powder-diffraction pattern [d in angstrom(I)(hkl)] are 3.672(100)(032), 3.660(64)(004), 3.407(60)(120), 3.319(62) ((1) over bar 21), 3.317(62)(121), 3.111(69)(041), 3.022(72)((1) over bar 13) and 3.017(72)(113). The mineral is named after the location. Both the mineral and its name were approved by the CNMNC (IMA #2003-064).

New species of Telenominae (Hymenoptera, Scelionidae) from the palaearctic fauna

Four new species of Telenominae of the genera Telenomus and Platytelenomus, collected in the territory of the Ukraine, Hungary, and Japan, were described: Telenomus (T.) bicolorus Kononova, T. (T.) ardens Kononova, (T.) michaylovi Kononova, and Platytelenomus mirabilis Kononova. Brief morphological characteristics of the genera Telenomus and Platytelenomus are given, and some notes concerning biology and geographical distribution of the species are presented. Telenomus (T.) bicolorus differs from all the known species of the genus Telenomus in the two-colored body: head and thorax yellow with brownish tint ventrally, mesothorax and abdomen black. The main distinguishing feature of T. (T.) ardens is its smooth shining body, T. (T.) michaylovi is similar to T. (T.) rudis Kozlov. These species can be distinguished by the structure of their antenna. The second to fourth segments of the antennal clava are transverse in T. (T.) michaylovi and are as long as wide in T. (T.) rudis. In addition, the abdominal stem and abdominal tergite II are smooth and shining, while the abdominal stem in T. (T.) rudis is striate along the entire length, and tergite II is finely striate along half of its length. Platytelenomus mirabilis is closely related to P. danubialis Szelenyi, but differs in the strongly flattened body, sculpture of the abdominal stem and tergite II, and coloration of the legs. The thorax of P. mirabilis is 4–5 times as wide as high, the abdominal stem is striate along the entire length, tergite II is striate at the base, and the legs, including coxae, are yellow. The thorax of P. danubialis is 4 times as wide as high, the abdominal stem and tergite II are smooth and shining, and the legs are brown.

Description and conditions of formation of new unnamed Ag-Cu and Ag-Cu-Au sulfotellurides in epithermal polymetallic Ag-Au-Te mineralization, Tinos Island, Hellas

Two new unnamed Ag-Cu ((Ag,Cu)12Te3S2) and Ag-A u-Cu ((Ag,Au, Cu)9Te2S3) or ((Ag,Cu)2|Au2Te§59) sulfotellurides were identified in low sulfidation epithermal Au-Ag-Te mineralization at Panormos Bay, Tinos Island, Greece. The sul­ fotellurides occur in stage V of nine paragenetic stages as minute, up to 13 pm in length, moderately reflective, white-gray isometric grains, with yellowish to brownish tint, depending on the gold and copper contents. The Ag-Cu sulfotelluride coexists with hessite and sylvanite in early stage V, whereas the Ag-Au-Cu sulfotelluride is in- tergrown with petzite and kostovite in late stage V. Both sulfotellurides also occur along the cleavages of hessite and petzite and replace stage II tetrahedrite. Based on silicate, sulfide, and telluride stabilities and fluid inclusion data, the con­ ditions of formation in stage V and the sulfotellurides formed between 230° to 260 °C at fS2 = 10~9 to 1095, f0 2 = 1035·86, fTe2 = 10-·92 to 10'938, pH = 5.74, aHTe (aq) = 2C)-io.88 and aH2Te(aqJ = 10 l20a, approximately. The gold and silver ion content in stage V solutions was 0.24 and 0.079 ppb, respectively.

LAFLAMMEITE, Pd3Pb2S2, A NEW PLATINUM-GROUP MINERAL SPECIES FROM THE PENIKAT LAYERED COMPLEX, FINLAND

Laflammeite, Pd 3 Pb 2 S 2 , is a new parkerite-type sulfide discovered in the Penikat layered complex, Finland. It occurs in altered pyroxenite in the Kirakkajuppura deposit in association with actinolite and clinochlore, accessory chromite, various platinum-group minerals [vysotskite, zvyagintsevite, cuprorhodsite – (ferrorhodsite) – malanite, laurite – erlichmanite, irarsite, keithconnite, unusual Pb–(Pd)-rich thiospinels of Cu, Fe, Rh and Ir, unnamed Pd 9 PbO 10 and Rh(Ni,Fe,Cu) 2 S 3 ], Pd-rich gold, and minor base-metal sulfides (chalcopyrite, bornite and millerite). Laflammeite occurs as individual subhedral to euhedral crystals up to 0.3 mm in size, and in intergrowths with Pt–Ni-poor vysotskite. Laflammeite is opaque and cream-colored with a brownish tint in reflected light in air. The anisotropy is weak, from brownish gray to grayish brown. The bireflectance is weak; pleochroism was not observed. Reflectance percentages in air (and in oil) are, for R 1 and R 2 , 45.3, 46.2 (31.55, 32.45) at 470 nm, 46.5, 47.55 (32.6, 33.75) at 546 nm, 47.7, 48.8 (33.9, 35.05) at 589 nm, and 49.6, 50.0 (36.0, 36.3) at 650 nm. Fine twins are present. Microhardness values VHN 50 are 156 and 185; the average is 171 kg/mm 2 . Cleavage is {010}, perfect. The average results of 26 wavelength-dispersion electron-microprobe analyses are Pd 39.16, Ir 1.08, Pb 52.01, S 7.90, total 100.15 wt.%, corresponding to (Pd 2.96 Ir 0.05 ) ∑3.01 Pb 2.02 S 1.98 (basis: 7 atoms per formula unit). The powder pattern was indexed on a monoclinic cell with a 11.521(11), b 8.294(10), c 8.321(6) A, β 134.38(5)°, V 568.3(6) A 3 . The space group is probably C 2/ m , with Z = 4. D calc is 9.41 g/cm 3 . The strongest lines in the pattern [ d in A(I)( hkl )] are: 5.953(6)(001), 4.144(10)(020), 2.917(9)(220), 2.413(8)(022), 2.365(7)(422) and 2.082(5)(040). Laflammeite likely crystallized from a hydrothermal fluid or a late-stage liquid in an environment poor in overall sulfur and rich in the PGE , Pb and volatiles.

Glomus eburneum and G. luteum, two new species of arbuscular mycorrhizal fungi, with emendation of G. spurcum

Two species of arbuscular mycorrhizal fungi, Glomus eburneum and G. luteum, are described and the description of G. spurcum is emended. All species produce spores singly in soil. Glomus eburneum spores are hyaline or white to cream, usually irregular (40 × 60 to 140 × 160 μm diam) and more rarely globose (40–140 μm diam). The spore wall consists of two adherent permanent hyaline layers, neither of which reacts in Melzer's reagent. The outer layer is thin (<1.2 μm), and the inner layer is finely laminate. Spores of G. luteum are globose to subglobose, 60–180 μm diam and pale yellow to dark yellow with a brownish tint. The spore wall consists of four layers, the two outer layers often degrading at maturity. The outer layer is mucilaginous and stains pinkish-red in Melzer's reagent. The second layer is hyaline and semirigid. Rigid, pale yellow to brownish yellow laminae comprise the third layer. Mature spores exhibit a fourth layer that is thin, flexible and may separate from the laminate layer under pressure. Both species were identified from pot cultures established with soil and root fragments from a semiarid giant sacaton (Sporobolus wrightii) grassland and subsequently cultured on sudangrass, Sorghum sudanense. Both species formed arbuscular mycorrhizae in pot cultures with corn (Zea mays) as the host.

Glomus eburneum and G. luteum, Two New Species of Arbuscular Mycorrhizal Fungi, with Emendation of G. spurcum

Two species of arbuscular mycorrhizal fun- gi, Glomus eburneum and G. luteum, are described and the description of G. spurcum is emended. All species produce spores singly in soil. Glomus ebur- neum spores are hyaline or white to cream, usually irregular (40 X 60 to 140 X 160 jim diam) and more rarely globose (40-140 ,um diam). The spore wall consists of two adherent permanent hyaline layers, neither of which reacts in Melzer's reagent. The out- er layer is thin (<1.2 ,lm), and the inner layer is finely laminate. Spores of G. luteum are globose to subglobose, 60-180 jLm diam and pale yellow to dark yellow with a brownish tint. The spore wall consists of four layers, the two outer layers often degrading at maturity. The outer layer is mucilaginous and stains pinkish-red in Melzer's reagent. The second layer is hyaline and semirigid. Rigid, pale yellow to brownish yellow laminae comprise the third layer. Mature spores exhibit a fourth layer that is thin, flex- ible and may separate from the laminate layer under pressure. Both species were identified from pot cul- tures established with soil and root fragments from a semiarid giant sacaton (Sporobolus wrightii) grassland and subsequently cultured on sudangrass, Sorghum sudanense. Both species formed arbuscular mycorrhi-

Osmium as an Immunostain Enhancement

Abstract Since we do our paraffin-section DAB immunostaining in an EM lab, we often use osmium to darken the reaction product. We simply put a drop of our standard 1% cacodylate-buffered osmium tetroxide on each section in a hood and rinse it off in running tap water after about 2 seconds. It makes light DAB reaction product pretty dark brown, and adds a light brownish tint to the rest of the section. The reaction increases the contrast quite a bit.

CHROMagar Candida, a new differential isolation medium for presumptive identification of clinically important Candida species

CHROMagar Candida is a novel, differential culture medium that is claimed to facilitate the isolation and presumptive identification of some clinically important yeast species. We evaluated the use of this medium with 726 yeast isolates, including 82 isolated directly on the medium from clinical material. After 2 days of incubation at 37 degrees C, 285 C. albicans isolates gave distinctive green colonies that were not seen with any of 441 other yeast isolates representing 21 different species. A total of 54 C. tropicalis isolates also developed distinctive dark blue-gray colonies with a halo of dark brownish purple in the surrounding agar. C. krusei isolates (n = 43) also formed highly characteristic rough, spreading colonies with pale pink centers and a white edge that was otherwise encountered only rarely with isolates of C. norvegensis. Trichosporon spp. (n = 34) formed small, pale colonies that became larger and characteristically rough with prolonged incubation. Most of the other 310 yeasts studied formed colonies with a color that ranged from white to pink to purple with a brownish tint. The only exceptions were found among isolates identified as Geotrichum sp. or Pichia sp., some of which formed colonies with a gray to blue color and which in two instances formed a green pigment or a dark halo in the agar. The specificity and sensitivity of the new medium for the presumptive identification of C. albicans, C. krusei, and C. tropicalis exceeded 99% for all three species. A blinded reading test involving four personnel and 57 yeast isolates representing nine clinically important species confirmed that colonial appearance after 48 h of incubation on CHROMagar Candida afforded the correct presumptive recognition of C. albicans, C. tropicalis, C, krusei, and Trichosporon spp. None of nine bacterial isolates grew on CHROMagar Candida within 72 h, and bacteria (Escherichia coli) grew from only 4 of 104 vaginal, 100 oral, and 99 anorectal swabs. The new medium supported the growth of 19 of 23 dermatophyte fungi tested and 41 of 43 other molds representing a broad range of fungal pathogens and contaminants. In parallel cultures of 348 clinical specimens set up on Sabourand agar and CHROMagar Candida, both media grew yeasts in the same 78 instances. CHROMagar Candida is recommended as a useful isolation medium capable of the presumptive identification of the yeast species most commonly isolated from clinical material and facilitating recognition of mixed yeast cultures.

Benefication of kaolin clay by froth flotation using hydroxamate collectors

The kaolin clays mined in Georgia contain two major impurities: anatase (TiO 2) and iron oxide. The anatase contains a considerable amount of iron in its lattice, which gives a brownish tint to the clays. This mineral is, therefore, removed by froth flotation to produce coating-grade (bright) clays. Anatase is commonly activated by divalent cations and floated using fatty acid collectors. The very small particle size anatase, however, necessitates long retention times in flotation. Often the separation efficiencies obtained with fatty acids are not adequate to produce high-brightness clays. Our recent studies have revealed that alkyl hydroxamates are much more effective than fatty acids in floating the colored anatase impurity from clays. No activators are required, and retention times in flotation are shorter than those for fatty acids. Promising results have been obtained in laboratory flotation tests. A viable process has also been developed for the large-scale manufacture of alkyl hydroxamates in novel formulations which were found to offer both metallurgical and economic advantages.

Tinting strength of carbon black

The tinting strength of carbon black (i.e., its efficiency in decreasing reflectance when mixed with a white pigment) is of practical importance in the paint industry and is also used in quality control of carbon black manufactured for use in rubber. The relative tinting strength of a carbon black is proportional to its specific absorbance, which we calculate by Mie theory from the refractive index of carbon black and the size of the independent structural units; namely, the fused aggregates, which as a first approximation are treated as solid spheres containing the same volume of carbon. This volume depends primarily on the particle size, and to a lesser but significant extent on the “structure” or number of particles per aggregate, which is calculated from the vehicle absorption at the critical pigment volume concentration. The refractive index of carbon black is estimated from various published data as m = 1.84 (1− 0.46 i). The Mie calculations show that the tinting strength is virtually independent of solid-sphere size below a certain value (approximately at a size parameter of α = 0.7); at larger sizes, the tinting strength diminishes gradually, and eventually becomes nearly proportional to 1/α. The calculated behavior is in good agreement with experimental findings. Calculations of the wavelength dependence of tinting strength show that carbon blacks of small solid-sphere size are of brownish tint “tone,” while those of large size are bluish, in agreement with experimental data. The effect of aggregate size distribution is discussed.