bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dust entrainability and its effect on explosion propagation in elongated structures
Authors: Ural Erdem A. 
Published: June 2004

AbstractTwo apparatuses have been developed to characterize the entrainability of dust deposits. The minimum aerodynamic wall shear stress required for dust removal (Critical Shear Stress), measured by the first apparatus, is an indicator of the ease with which dust particles can be removed from a layer. The second apparatus measures the settling velocity distribution of dust clouds, which is an important factor controlling the extent of dispersion as well as the time period during which the entrained dust cloud can remain suspended.Testing has shown that the critical shear stress depends not only on the nature of the dust, but on the way the dust deposit is formed. Therefore, a portable version of this apparatus was developed to allow field testing of dust deposits. This methodology has also been used to evaluate the effect of oil treatment sometimes used in the grain handling industry to reduce dust emission.Simulated explosion tests have demonstrated the importance of critical shear stress on dust entrainability. A simple model calculating unsteady dust concentration in elongated structures has been developed. The model shows that flammable dust concentrations induced in a gallery by a primary explosion exist over a finite length and time period. Therefore, the probability of a secondary explosion depends not only on the dust and layer properties, but on the details of the primary explosion and of the enclosure geometry. A simple criterion for transmission of a primary explosion into an adjoining elongated structure is discussed in the paper.
Laboratory and large‐scale dust explosion research
Authors: Cashdollar Kenneth L. , Weiss Eric S. , Greninger Nevin B. , Chatrathi Kris 
Published: June 2004

AbstractThis paper describes dust explosibility research in full‐scale experimental mines and a 20‐L laboratory chamber at the U.S. Bureau of Mines and in a 1‐m3 laboratory chamber at Fike Corporation. The purpose of this research is to improve safety in mining and other industries that manufacture, process, or use combustible dusts. As part of this work, carbonaceous dusts with a wide range of volatilities and various particle size distributions were studied. Laboratory data on the minimum explosible concentrations of predispersed dusts were comparable to mine data for nominal dust loadings that were dispersed by the aerodynamic disturbance from a gas ignition zone. Recommendations are given on the limitations of small‐scale testing such as “overdriving” by too strong of an ignitor. The effect of dust particle size on explosibility data is illustrated for coal and aluminum dusts. For both dusts, the finest sizes were the most hazardous. The inerting requirements for preventing explosions were also measured in both laboratory and large‐scale systems. All the data show relatively good agreement between the laboratory and the large‐scale tests.
Determination of an improved set of harmonic force constants for benzene
Authors: Rashev Svetoslav 
Published: June 2004

AbstractThe aim of this work is to describe a specific completely symmetrized, combined local mode/symmetrized modes (LM/SM), nonperturbative vibrational calculation procedure, and computer code, designed for implementation of large‐scale calculations on the vibrational energy levels in benzene C6H6, as well as its D6h isotopomers. Using this procedure and code, calculations have been performed on the fundamental frequencies of benzene, using the harmonic force constants, as well as a very small number of anharmonic constants, as adjustable input parameters. In this way, an improved set of symmetrized harmonic force constant values for benzene C6H6 have been determined, allowing for very good reproduction of the fundamental frequencies. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Tarnen und Täuschen — Chronologie eines Cracks
Authors: Dubrawsky Ido 
Published: June 2004

AbstractSo schwer war das gar nicht. Jedenfalls hatte ich Schlimmeres erwartet. Also tatsächlich war es eigentlich ein Kinderspiel. Man musste sich nur ein paar Gedanken machen. Das reichte. Scheint so, dass die meisten Sicherheitsleute denken, wenn man Router und Firewalls und Intrusion Detection Systeme (IDS) einsetzt, dann haben sie ihr Netzwerk abgesichert. Aber das trifft nicht notwendigerweise zu. Es braucht nur eine klitzekleine Fehlkonfiguration irgendwo im Netzwerk oder auf einem Server, damit einer durch diese Lücke schlüpfen kann …
Risikomanagement in Energiemärkten (Teil I)
Authors: Trück Stefan , Weron Rafal 
Published: June 2004

AbstractDie folgende Serie vermittelt unter Berücksichtigung des Risikomanagement‐Aspekts einen Überblick über den Stromhandel und die Modellierung von Preisen in Energiemärkten.Der erste Teil gibt zunächst eine kurze Einführung über den Stromhandel in Deutschland. Hierbei stehen vor allem die Entwicklung des Strommarktes in der letzten Dekade sowie die entstandene Strombörse EEX in Leipzig bzw. die dort gehandelten Produkte im Vordergrund. Darüber hinaus werden die Zusammenhänge und Einflussfaktoren beim Preisbildungsprozess für Strom dargestellt, sowie Besonderheiten der Strompreise wie etwa Saisonalitäten, hohe Volatilitäten etc. verdeutlicht.Im zweiten Teil der Serie (erscheint in der RISKNEWS 04/2004) werden dann Möglichkeiten der Modellierung von Strompreisen vorgestellt. Hier geht es vor allem um die Berücksichtigung von Saisonalitäten, der Mean‐Reversion‐Eigenschaft und die Modellierung von Preissprüngen. Ein dritter Teil (erscheint in der RISKNEWS 05/2004) erläutert schließlich verfeinerte Methoden der Modellierung sowie Ansätze des Risikomanagements in Energiemärkten.
Undergraduate students' understanding of falling bodies in idealized and real‐world situations
Authors: Cahyadi M. Veronica , Butler Philip H. 
Published: June 2004

AbstractThis study investigates the understanding of 18 first‐year undergraduate students when simultaneously presented with two contrasting dynamical situations: the idealized (without air resistance) and real‐world cases of balls being dropped or thrown. Previous work has shown that getting students to recognize flaws in their mental models helps them develop their understanding. Our students were better able to answer correctly the problems in idealized cases than the problems in real‐world cases. For the real‐world cases, the students understood the impact of air resistance on the object's size better than the impact of air resistance on objects of the same size but different mass. In follow‐up interviews, the students reported that using the two different situations in the same test did indeed encourage them to think more carefully. By recognizing the need to include air resistance, they activated their appropriate mental “resources” to deal with the situations. We conclude that using contrasting situations (i.e., with and without an idealization) is a useful teaching tool. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 569–583, 2004
Visual impairment and ocular abnormalities in children with fetal alcohol syndrome
Authors: Strömland Kerstin 
Published: June 2004

AbstractChildren with fetal alcohol syndrome (FAS) may have impaired vision and various ocular abnormalities. All parts of the eye may be affected and anomalies such as microphthalmus, microcornea, Peters' anomaly, cataract, persistent hyperplastic primary hyaloid vitreous body, coloboma of the iris and choroid, retinal dysplasia and, most commonly, optic nerve hypoplasia and tortuosity of the retinal vessels, have been reported. The periocular facial features consist of short palpebral fissures (included in the criteria for diagnosis of FAS), telecanthus, epicanthus and blepharoptosis. Visual function may be reduced to a moderate or severe degree. Refractive errors and strabismus are common. Considering the high frequency of ocular pathology in FAS, an ophthalmological examination is helpful in making the diagnosis. The early detection of impaired vision and ocular abnormalities in affected children is important in the management of the disorder. In this article, the ophthalmological signs and symptoms in children with FAS are presented.
HURLER'S SYNDROME
Authors: Danes B. Shannon , Bearn Alexander G. 
Published: June 2004

Seven families affected with Hurler's syndrome have been studied using the methods of cell culture. Skin fibroblasts obtained from the skin of 7 patients with Hurler's syndrome contained metachromatic granules when stained for mucopolysaccharides with toluidine blue O and alcian blue, whereas fibroblasts from normal subjects contained no metachromatic granules.
In four families skin cultures of the clinically normal parents showed fibroblasts which contained demonstrable metachromatic granules and "gargoyle" cells and were considered to be heterozygous for the abnormal gene. Fibroblast cultures from certain other members of these families showed metachromasia. These findings were also considered to indicate heterozygosity for the abnormal gene.
Three families of the X-linked type of the disease were studied. Fibroblasts cultured from the father contained no metachromatic granules whereas those of the hemizygous mother contained both metachromatic granules and "gargoyle" cells. In one family the abnormal gene could be traced through unaffected individuals for three generations. The prolonged preservation of the biochemical trait in tissue culture will permit studies to be performed designed to clarify the primary action of the abnormal genes which result in Hurler's syndrome, as well as to increase the usefulness of this trait in mapping the human X chromosome.
THE FUNCTIONS OF THE THYMUS SYSTEM AND THE BURSA SYSTEM IN THE CHICKEN
Authors: Cooper Max D. , Peterson Raymond D. A. , South Mary Ann , Good Robert A. 
Published: June 2004

The bursa of Fabricius and the thymus are "central lymphoid organs" in the chicken, essential to the ontogenetic development of adaptive immunity in that species. Surgical removal of one or both of these organs in the newly hatched chicken, followed by sublethal X-irradiation the next day, has permitted recognition of two morphologically distinct cell systems in the "peripheral lymphoid tissues" of the spleen, gut, and other organs, and clear definition of the separate functions of each cell system.
The thymus-dependent development is represented morphologically by the small lymphocytes of the circulation and the white pulp type of development in the tissues. As in mammals, the thymus-dependent tissues of the chicken are basic to the ontogenesis of cellular immunity: graft versus host reactions, responses of delayed hypersensitivity and homograft rejection; and play a less clearly defined role in the antibody response to at least some antigens. Thymectomized-irradiated chickens are deficient in all these responses, and grow more slowly than any of the other experimental groups. In these animals germinal centers, plasma cells, and capacity for immunoglobulin synthesis remain intact.
The bursa-dependent development is represented morphologically by the larger lymphocytes of the germinal centers and the plasma cells, and functionally by the immunoglobulins. Bursectomized-irradiated chickens are agammaglobulinemic and unable to produce detectable antibody despite intense, repeated stimulation with bovine serum albumin and Brucella abortus organisms. The thymus-dependent development in these animals seems to be normal; they have adequate numbers of lymphocytes in the circulation and tissues, are able to reject skin homografts, though more slowly than usual, and to exercise graft versus host reactions. The short life span of these chickens has precluded adequate study of responses of delayed hypersensitivity.
There was no evidence of significant impairment of reticuloendothelial function in either the bursectomized-irradiated or the thymectomized-irradiated group, as judged by the clearance of colloidal gold and I131-tagged keyhole limpet hemocyanin.
THE ROLE OF THE MICROBIAL FLORA IN UREMIA
Authors: Einheber Albert , Carter Darryl 
Published: June 2004

Germfree rats were used in 3 experiments to study the effects of the microbial flora on survival time after acute uremia produced by a one-stage bilateral nephrectomy. Germfree rats, limited-flora rats, and conventionalized rats (all maintained continuously in isolators) were subjected to nephrectomy or to sham nephrectomy, deprived of food and water until they died, respectively, of uremia or of starvation, and their survival times compared. To establish a limited defined flora in advance of nephrectomy, germfree rats were either monocontaminated (Staphylococcus albus), dicontaminated (S. albus and Proteus mirabilis) or tetracontaminated (S. albus, S. faecalis, P. mirabilis, and E. coli); to conventionalize germfree rats, they were exposed to the mixed microbial flora contained in the cecal contents of ordinary rats, which was the source of the aforementioned bacteria and which included other uncharacterized microorganisms as well.
The intestine of all rats with a limited flora persisted in a morphologic state that was virtually no different from that of the germfree rat, including the presence of an enlarged, thin-walled cecum; by contrast, the intestine of the conventionalized rats permanently assumed the morphological characteristics of ordinary, open-laboratory rats with the cecum reduced to normal size.
After nephrectomy and food and water deprivation (death from anuria):
(a) All germfree rats but one outlived their conventionalized counterparts in each of the 3 experiments; the 21 germfree rats (127 hr) lived, on the average, 2 days longer than did the 24 conventionalized rats (75 hr). No sex difference was demonstrated.
(b) The rats with a limited flora died correspondingly sooner as the complexity of their flora increased; survival time of the tetracontaminated rats was significantly shorter than that of the germfree rats, and statistically no different from that of the conventionalized rats.
After sham nephrectomy and food and water deprivation (delayed death from starvation):
(a) All rats, irrespective of microbial status or sex, outlived their fasting nephrectomized partners. The conventionalized rats endured starvation approximately 2.5 wk longer than they did anuria and the germfree rats 1 wk longer.
(b) All conventionalized rats, both male and female, outlived their respective germfree counterparts by about 1 wk.
(c) All males, irrespective of microbial status, survived longer than did the females; the average difference was 4 days.
The differences in tolerance to anuria or starvation did not correlate with initial body weight or rate of weight loss.
THE ROLE OF THE MICROBIAL FLORA IN UREMIA
Authors: Carter Darryl , Einheber Albert , Bauer Heinz , Rosen Hyman , Burns Willard F. 
Published: June 2004

Uremic colitis of varying severity occurred in the majority of conventionalized rats dying after removal of both kidneys, but was not found in uremic conventionalized and germfree rats sacrificed preterminally, or in germfree and limited-flora rats dying from uremia, or in any of the controls. The lesions were restricted to the cecum and their incidence and severity paralleled a shorter duration of survival. Cardiovascular damage including focal myocardial necrosis and calcification and patchy aortic and coronary calcification were observed in uremic rats regardless of their microbial status. These lesions had a higher incidence, developed more rapidly, and were more severe in the germfree and limited-flora rats than in the conventionalized animals. The presence or severity of the lesions, however, did not correlate with survival time of rats dying from uremia or with total plasma calcium and inorganic phosphorus levels of individual animals. Generalized necrotizing arteritis was not observed. Wound healing was poor in all uremic rats regardless of microbial status. Focal infection was noted in a few conventionalized rats dying from uremia, did not correlate with survival time, and was absent in all other groups.
Comparison of biochemical findings between uremic germfree and conventionalized rats show a higher blood urea nitrogen and elevated plasma indoxyl sulfate in the presence of a microbial flora and a greater amount of plasma inorganic phosphorus in its absence. Uremia resulted in a decrease in hematocrit and increase in plasma and muscle potassium that were similar for germfree and conventionalized rats. Plasma and muscle sodium, total plasma calcium, glucose, and total protein were essentially unchanged by microbial status or uremia.
Because the foregoing differences in the metabolic and histopathologic changes of uremia are linked to the known difference in microbial status of the fasting bilaterally-nephrectomized rats that were studied, they are a tangible indication of ways by which the indigenous microbial flora and its composition may affect the course of acute uremia.
THE RENAL LESION ASSOCIATED WITH HEMOGLOBINEMIA
Authors: Jaenike John R. , Schneeberger Eveline E. 
Published: June 2004

Histological studies have been performed on experimental acute renal failure induced by intravenous injection of hemoglobin in rats. These have been correlated with alterations in renal excretory function, assessed by the measurement of inulin clearance, at various stages of the lesion. The most prominent morphological changes during the first 24 hr after hemoglobin injection, when inulin clearance is most markedly suppressed, are: the presence of hemoglobin within the lumen of small intrarenal vessels, particularly the vasa recta; hemoglobin cast formation involving predominantly the thick ascending limbs of the loops of Henle; and evidence of injury of the epithelium of the proximal tubules and thick ascending limbs. Notably absent during this stage of the lesion are marked tubular dilatation, interstitial edema, and cast formation in the distal collecting ducts. The considerable recovery of function which occurs at 72 hr is accompanied by a marked reduction in involvement of the vasa recta. Standard sections and microdissection reveal many markedly dilated proximal tubules at this stage of the lesion, suggesting obstruction of filtering nephrons.
These data have led to a tentative hypothesis regarding the pathogenesis of renal failure in this experimental lesion. It is suggested that renal ischemia and failure of glomerular filtration are the primary factors responsible for the early and severe impairment of renal function, and that these are related to intravascular aggregation of hemoglobin pigment. As this defect recedes, tubular obstruction by hemoglobin casts prevents restitution of excretory function in a variable fraction of the nephrons. The latter accounts for the relatively prolonged, moderate reduction in inulin clearance associated with the late stages of this lesion. These hypotheses form the basis for a continuing study of this renal lesion.
THE IGA SYSTEM
Authors: South Mary Ann , Cooper Max D. , Wollheim Frank A. , Hong Richard , Good Robert A. 
Published: June 2004

1. Five patients with congenital or acquired agammaglobulinemia, lacking detectable IgA in serum or saliva, were transfused with 1 to 2 liters of normal plasma. In 2 of these patients IgA was demonstrated in parotid saliva collected after transfusion, but in none of the 5 was salivary IgG or IgM found. This observation indicates the selective transport of IgA into saliva.
2. The observation by others of an immunochemical difference between serum and sahvary IgA globulin was confirmed. In contrast to serum IgA, salivary IgA is attached to a protein having antigenicity which migrates as a gamma1 globulin. We have termed this protein component "transport piece".
3. The transport piece has been found in an unbound form in the saliva of persons completely lacking IgA: agammaglobulinemic patients, ataxia-telangiectasia patients, a healthy person lacking IgA, and a newborn infant. Free transport piece still occurs in the normal child's saliva after IgA production begins. By adulthood there is usually no free transport piece in the saliva.
4. Heat-aggregated salivary IgA, like heat-aggregated serum IgA, does not fix complement.
5. Our findings offer support for the view that there is a distinct local antibody system for the protection of the mucous surfaces.
COLICINE K
Authors: Hinsdill Ronald D. , Goebel Walther F. 
Published: June 2004

1. The transfer of type K. colicinogeny to Shigella sonnei Phase II has been described.
2. The colicine elaborated by this microorganism is a lipopolysaccharide-protein complex which resembles the somatic antigen of the noncolicinogenic parent.
3. Although the colicine K of Escherichia coli K235 and of Sh. sonnei differ both chemically and serologically, they resemble each other in that both elicit type K colicine-neutralizing antibodies and both have the same bactericidal specificity.
4. The nature of the chemical changes brought about in the somatic antigen of Sh. sonnei through the acquisition of colicinogeny remains unknown
STUDIES OF PPLO INFECTION
Authors: Thomas Lewis , Davidson Morton , McCluskey Robert T. 
Published: June 2004

Turkey poults injected intravenously with suspensions of Mycoplasma gallisepticum develop a fatal neurologic disease associated with polyarteritis affecting almost exclusively the cerebral arteries. The incubation period depends on the dose of organisms. With high doses (1010 to 1011 mycoplasmas) the birds become ill and die within a few hours; with lower doses (106 to 108) neurologic manifestations appear after 7 days. The rapid onset of neurologic signs after high doses indicates the presence of a toxin in the mycoplasma, but efforts to extract toxin from disrupted organisms or to demonstrate its presence in culture fluid free of mycoplasmas have been unsuccessful. The toxin appears to be associated only with living mycoplasmas.
The toxic component of M. gallisepticum is inactivated by heating the organisms at 50°C, disruption by repeated cycles of freezing and thawing, and exposure to specific antibody.
Treatment of turkeys with gold thiomalate furnishes partial protection against the toxic effects of large doses of mycoplasmas, and protection against the development of cerebral arteritis. Treatment with tetracycline protects completely against both toxicity and arteritis, and, when delayed, restores diseased birds to a healthy state. Cortisone, methotrexate and 6-mercaptopurine have no effect on the course or outcome of the disease.
Intracerebral injections of M. gallisepticum are less toxic and lethal than when the same dose was given by vein, indicating that the organism exerts its damaging action on blood vessels by way of the blood stream.
The arterial lesions resemble those of serum sickness, except for their distribution, and are associated with glomerular inflammatory lesions. However, for various reasons discussed, it is considered more likely that they result from a direct toxic action of living mycoplasmas on the vessels concerned than from an immunologic mechanism.