Brown Crust Research Articles

Chemical reactions at the liquid-solid interface in meso/microporous inorganic gels and glasses

Interfacial reactions between concentrated aqueous solutions of iron nitrate and alumina or aluminosilicate meso- or microporous monolithic gels and glasses have been studied by IR absorption, Raman scattering, N 2 adsorption measurements, X-ray absorption (EXAFS) spectroscopy and scanning electron microscopy. Comparison is made with monoliths impregnated with cobalt nitrate solution. For the former, the reaction occurring at the monolith surface is described by the formation of an FeOOH-like hydroxide at the pore opening, whereas the nitrate ions diffuse into all the pores. A diffusion of iron ions inside the AlOSi framework, to give an Fe 1− x (Al, Si) x OOH phase, is assumed to explain the vibrational and EXAFS spectra as well as the formation of a brown crust around the optically clear NO 3 − impregnated core. Further heating of the outer crust under H 2 leads to metallic iron, αFe as well as spinel formation [γFe 2O 3 (maghemite) or Fe 3O 4]. These precipitates give rise to αFe 2O 3 (hematite) in air. A 1340cm −1 band seems to indicate the formation of amorphous diamond-like precipitates between 1000 °C and 1300 °C.

Gypsum ground: a new occurrence of gypsum sediment in playas of central Australia

There are many playas (dry salt lakes) in arid central Australia (regional rainfall about 250 mm/y and pan evaporation around 3000 mm/y). Highly soluble salts, such as halite, only appear as a thin (several centimetres thick), white, ephemeral efflorescent crust on the dry surface. Gypsum is the major evaporite precipitating both at present and preserved in sediment sequences. One type of gypsum deposit forms a distinctive surface feature, which is here termed “gypsum ground”. It consists of a thick (up to 80 cm) gypsum zone which rises from the surrounding smooth white playa surface and is overlain by a heaved brown crust. The gypsum zone, with an average gypsum content above 60%, consists of pure gypsum sublayers and interlayered clastic bands of sandy clay. The gypsum crystals are highly corroded, especially in the direction parallel to the c-axis and on the upper sides where illuviated clay has accumulated in corrosion hollows. Overgrowth parallel to the a- and b-axes is very common, forming highly discoidal habits. These secondary changes (corrosion and overgrowth) are well-developed in the vadose zone and absent from crystals below the long-term watertable (depth around 40 cm). These crystal characteristics indicate a rainwater leaching process. At Lake Amadeus, one of the largest playas (800 km 2) of central Australia, such gypsum ground occupies 16% of the total area. The gypsum ground is interpreted as an alteration of a pre-existing gypsum deposit which probably extended across the whole playa before breaking down, leaving a playa marginal terrace and several terrace islands within the gypsum ground. This pre-existing gypsum deposit, preserved in the residual islands, consists of pure, pale, sand-sized lenticular crystals. It is believed to have been deposited during an episode of high regional watertable, causing active groundwater seepage and more frequent surface brine in the playa. A later fall in watertable, probably resulting from climatic change, caused the degradation of the gypsum deposit by dissolution and leaching processes. The common distribution of the gypsum ground and marginal terraces in the playas of central Australia demonstrates the extent of this hydrologic and climatic history.

An evaluation of by-products from wheat distillation as feeds for ruminant livestock

During the distillation of wheat to produce whisky, two residual products are formed. These are the spent grains and a thick syrup resulting from evaporation of the liquor remaining after the whisky has been distilled off. These by-products may be combined to form undried dark grains (UDG) or further dried and pelleted to form wheat distillers dark grains (WDDG). UDG and WDDG were evaluated as feeds for ruminant livestock.WDDG had the appearance of a typical concentrate pellet, dark brown in colour with a molasses like malty odour. UDG was lighter brown in colour but formed a dark brown surface crust on exposure to air. The bulk of the material had a granular putty-like texture and a smell akin to that of WDDG. Compositions of the two by-products and that of distillers dark grains derived from barley fernentation alone are given in Table 1.

An iridium anomaly in the Middle‐Lower Jurassic of the Venetian Region, northern Italy

A significant iridium enrichment has been found in a Jurassic marine sequence, about 180 million years old, outcropping in the Alps of the Venetian region. The maximum iridium concentration of 3.2 ± 0.2 ng·g−1 occurs in a brown crust 2–3 mm thick, containing essentially iron hydroxide. This crust, characterized by a nearly total absence of detritic components, lies on top of upper Lias limestones, and is overlaid with Bajocian‐Bathonian limestones. The origin of the Ir anomaly is not clearly understood yet but could be explained by either a drop in the sedimentation rate resulting in the concentration within a thin sediment layer of the normally infalling cosmic dust and/or by an increase of cosmic material infall following an asteroid or comet impact(s).

A Case of Possible Penicillium Tinea Capitis

To the Editor.— Penicillium is rarely reported as an infectious agent in man. This mold is ubiquitous in nature and its frequent isolation in cultures is routinely ascribed to contamination. 1(pp456-458) We report a case of tinea capitis in which Penicillium may have been the causative agent. Report of a Case.— A 3-year-old boy was seen in January 1982 with a one-month history of patchy occipitoparietal hair loss with loss of luster in the remaining hair, and scattered black dots and light brown crusts on the scalp. Results of a Wood's light examination at that time were normal. Results of potassium hydroxide examination of epilated hairs were also normal; the brownish crusts showed brown, double-walled spores, some of which were clumped. A culture grown on dermatophyte test medium showed Penicillium species. The patient began receiving 50 mg of ketoconazole daily. Minimal fungicidal drug concentration studies against the organism were

Heteromorphic algal life histories: The seasonal pattern and response to herbivory of the brown crust, Ralfsia californica.

Little is known about the natural history of crustose phases of heteromorphic algae. A qualitative model describing their life history strategies has hypothesized that the morphologies and seasonal occurrences of the two phases evolved largely in response to variable grazing pressure. Crustose phases are predicted to occur when grazing is intense, and erect phases when grazing is reduced. The brown algal crust Ralfsia calfornica, which is the non-obligatory alternate phase of Scytosiphon lomentaria and/or Petalonia fascia, was studied on San Juan Island, Washington, USA. Both phases inhabit pools in the midto upper-intertidal zone, with the crust reaching maximum abundance between 1.8 and 2.3 m. The crust undergoes radical and predictable seasonal fluctuations in abundance, with a maximum in March-April and minimum in August. The erect phases are winter annuals, with maxima in January-April. Thus the crustose and erect phases show high temporal overlap. Colonization studies on new substrata showed that: 1) the crust is ephemeral, with a lifespan of 7-12 months, 2) it reproduces throughout the year and its propagules rapidly colonize new substrata at almost any time, while 3) erect phases appear only during the winter. Manipulations of limpets indicated that they do not directly graze the crust and are not responsible for its seasonal fluctuations in abundance; however, they are crucial to its persistence because they remove potential competitors. The crust fits poorly into models relating morphology to successional status in that it is ephemeral and opportunistic yet is grazer-resistant and grazer-dependent. Furthermore, both the crust and its erect phases are most abundant in the winter, when grazing appears to be least intense. Thus this heteromorphic complex exhibits interesting characteristics not predicted by current models.

Microwave Energy for Bread Baking and its Effect on the Nutritive Value of Bread: A Review

Microwave energy offers savings in labor, processing time, and space in bread baking. Two constraints, however, limit its application: microwave-baked bread lacks the characteristic brown crust, and baking pans, inexpensive and suitable, are still to be developed for microwave baking of sandwich-type breads. To provide the brown crust, a combined microwave and thermal heating process was recommended to prepare brown-and-serve rolls and white bread. By such a process, a flour with low protein content and high alpha-amylase could be used to prepare acceptable bread. Combined microwave and thermal heating also was suggested to proof dough and bake it to reduce processing time and energy required for bread making. Microwave energy also was found practical to bake relatively dark breads such as whole-wheat and rye breads where brown crusts were less important. Nutritionally, microwave baking does not produce browning reactions to reduce the availability of lysine so it minimizes nutritive losses during baking.

Hydrothermal treatment of sprout-damaged grain: II. Effects on the technological quality of rye

Sprout-damaged rye with the falling number of 87 was heat-treated by immersing the grain in water having temperatures of 80, 90 and 100°C. The treatment lasted at the most 60 sec and was followed by an immediate chilling process. The aim of the treatment was to suppress the excess of a-amylase activity in the outer layers of the kernels. The changes in the quality of the rye were determined by the falling number test, amylograph test and baking tests in which yeast and no acid was added. All the performed treatments affected the results of the quality determinations. Treatment at 80, 90 and 100°C lasting 30 sec raised the falling number values to 102, 117 and 155, respectively. After treatment for 60 sec the values were 101, 142 and 223. In the amylograms the peak viscosity increased markedly. Processing at 100 and 90°C for more than 20 sec resulted in an increase of the peak viscosity beyond 1000 B.U. The peak temperature of all the samples was rather low and some decrease in the peak temperature was indicated at the processing temperatures of 80 and 90° C. The loaf volumes of loaf made from the treated samples were all lower than the volume of the loaf from the untreated sample. The samples treated for 30 and 60 sec at 100°C gave lowest volumes. Stickiness of the doughs was diminished by the more severe processing conditions, as also were dampness and elasticity of the crumb. All loaves except the ones made of grain heated at 100“C for 30 and 60 sec had a rather large cavity beneath the crust. The samples processed at 90 and 100°C for 30 and 60 sec gave a lighter brown crust colour than the rest of the samples.

EFFECTS OF CONVENTIONAL BAKING, MICROWAVE BAKING, AND STEAMING ON THE NUTRITIVE VALUE OF REGULAR AND FORTIFIED BREADS

ABSTRACTThe nutritive value of protein in regular and fortified breads was significantly affected by methods of baking. Rat‐feeding tests demonstrated that protein efficiency ratios (PERs) of breads were significantly improved and feed conversion ratios were reduced by substituting steaming or microwave baking for conventional baking. Lysine and other amino acids varied little among conventionally baked, microwave baked, and steamed breads. The significantly low PER of conventionally baked bread indicated that lysine became less available nutritionally with conventional baking than with either microwave baking or steaming. Lysine or soy fortification could effectively raise the PER of conventionally baked bread. Loaf volume and crumb qualities of conventionally baked bread were better than those of microwave‐baked or steamed bread. However, conventional baking produced a much darker brown crust and crumb than did microwave baking or steaming. The effect of heating, as shown by browning, on reducing the bread's nutritive value could be greatly minimized by replacing conventional baking with microwave baking or steaming.

The Biology of Brown Algae on the Atlantic Coast of Virginia. II. Petalonia fascia and Scytosiphon lomentaria

Microscopic, brown algal crusts and filaments were collected in the summer from an oyster reef on the Atlantic coast of Virginia and isolated into culture. Developmental studies showed that the isolates were microscopic stages ofPetalonia andScytosiphon. These two brown algae exist the year around in the form of either microscopic or macroscopic plants. In culture no sexual reproduction was found linking the two stages of eitherPetalonia orScytosiphon. The zoospores from the macroscopic plants ofPetalonia andScytosiphon developed directly into crusts and initials on the crusts developed directly into macroscopic plants. Culture conditions of 10 C and a 9–15 hour photoperiod stimulated the development of macrothalli in both taxa.

ULCERATING HEMANGIOBLASTOMA

CHRONIC ulceration of the lower extremities is one of the more common perplexing problems of medical practice. The following case is reported because of the unusual histologic observations. A thorough search of recent literature failed to reveal any comparable cases. REPORT OF A CASE W. J., a Negro, aged 30, was first admitted on Jan. 15, 1932 for surgical treatment of a duodenal ulcer. Examination on admission revealed as an incidental discovery ulceration on the front of the left leg, occupying the entire mid-portion, 5 inches (12.7 cm.) in length and 2 inches (5 cm.) in width and covered by a firmly adherent brown crust. The surrounding skin was deeply pigmented. No discharge was noted. The patient stated that at the age of 9, following a blow to this region a sore developed which discharged pus and then pieces of bone. Frequently the lesion would heal over completely and then

GRANULOMA SENILIS

In 1927, Kreibich reported a case of what he called granuloma senilis, in which the following history was given. A woman, aged 55, had had about fifty typical warts on her back for many years. During the last three months, two of them had ulcerated and appeared as red nodular elevations, one as large as a hazelnut, the other the size of a pigeon's egg. After removal of a brown crust, an irregular papillomatous surface was seen which on one edge was continuous with a senile wart. It was diagnosed as carcinoma of a senile wart and was excised. Histologically, there was a definite epithelial margin of basal cells. With the exception of the superficial ulceration and edema of the rete pegs, the section was similar to that of the adjacent senile warts. In calling this lesion a granuloma senilis, Kreibich pointed out that the name indicates a granuloma of

V.—Notes on the Olifant Klip from Natal, the Transvaal, and Lydenburg

I.—Specimen from one of the blocks lying on the Ecca Shale on the declivity near the Klip River at the Station Hospital, Ladysmith. This is a bluish-grey rock of close texture, with a flaky and sometimes conchoidal fracture. The broken surface does not reveal the rock's internal structure; but on the weathered surface, which appears as a brown crust, the siliceous strings and bands passing through the rock stand out in high relief. The surface effervesces freely when touched with acid.