Showing papers by "Virginia Commonwealth University published in 1973"
TL;DR: In this paper, the authors present the theory and development of an algorithm associated with the exploration of a dual response surface system, where a user can generate simple two dimensional plots to determine the conditions of constrained maximum primary response regardless of the number of independent variables in the system.
Abstract: The purpose of this paper is to present the theory and develop an algorithm associated with the exploration of a dual response surface system. The approach is to find conditions on a set of independent or “design” variables which maximize (or minimize) a “primary response” function subject to the condition that a “constraint response” function takes on some specified or desirable value. A method is outlined whereby a user can generate simple two dimensional plots to determine the conditions of constrained maximum primary response regardless of the number of independent variables in the system. He thus is able to reduce to simple plotting the complex task of exploring the dual response system. The procedure that is used to generate the plots depends on the nature of the individual univariate response functions. In certain situations it becomes necessary to apply the additional constraint that the located operating conditions are a certain “distance” from the origin of the independent variables (or the cent...
287 citations
122 citations
TL;DR: The degree of renaturation between Nocardia farcinica 330 deoxyribonucleic acid (DNA) and DNA from 17 nocardial strains and 11 mycobacterial strains, and between Mycobacterium smegmatis 405 DNA andDNA from 11Mycob bacterial strains and 14 nocardIAL strains was determined by using the nitrocellulose membrane filter technique.
Abstract: The degree of renaturation between Nocardia farcinica 330 deoxyribonucleic acid (DNA) and DNA from 17 nocardial strains and 11 mycobacterial strains, and between Mycobacterium smegmatis 405 DNA and DNA from 11 mycobacterial strains and 14 nocardial strains was determined by using the nitrocellulose membrane filter technique. These results indicated that some cultures designated N. farcinica were identical to some cultures designated N. asteroides but that other strains called N. asteroides were distinctly different. The species M. smegmatis was homogeneous and distinct from the other species examined. Data comparing the extent of nucleotide sequences shared by M. smegmatis 405 DNA and DNA from nine other mycobacterial strains, as determined by the membrane filter technique and by monitoring DNA reassociation optically, were similar. The extent of reassociation between M. tuberculosis H37Ra DNA and DNA from 14 mycobacterial strains was determined optically. DNA from M. bovis BCG was 86% homologous with M. tuberculosis H37Ra DNA. The other mycobacterial DNA preparations examined were less than 40% homologous with M. tuberculosis H37Ra DNA. The genome sizes of the mycobacteria examined ranged between 2.5 x 10(9) daltons and 4.5 x 10(9) daltons.
97 citations
TL;DR: In this article, two sediment cores drawn from springs in the Cuatro Cienegas Basin, a small desert valley in central Coahuila, yielded fossil pollen chronologies transgressing more than 30,000 radiocarbon years.
Abstract: Two sediment cores drawn from springs in the Cuatro Cienegas Basin, a small desert valley in central Coahuila, yielded fossil pollen chronologies transgressing more than 30,000 radiocarbon years. Comparisons of modern pollen spectra from the basin floor with the fossil records indicate that vegetation ecologically equivalent, if not identical, to that now present has occupied the floor of the basin since mid—Wisconsin time. A highly—endemic fauna and a lack of geological evidence for large Pleistocene lakes in the area afford strong support for this interpretation, and suggest that aquatic and terrestrial habitats of the valley lowlands remained stable environments throughout the Quaternary, regardless of fluctuations in regional climate. Fossil arboreal and Compositae pollen sequences provide a means for making stratigraphic correlations between the cores, and are the first late—Quarternary palynoclimatic chronologies available from northeastern Mexico. Trends in those components of the fossil records indicate that regional climate was cooler and perhaps more moist during the last Pluvial than at present. It became progressively warmer and drier during late—Pluvial time, and approximated modern climate during the Holocene. Holocene Altithermal or Hypsithermal intervals were undetected, but may be obscured by gaps in the fossil records.
96 citations
88 citations
TL;DR: An optical source simulating the sun at the top of the atmosphere has been constructed and used to obtain retinal burn thresholds in the rhesus monkey for image diameters corresponding to that of the solar disk on the human retina.
Abstract: An optical source simulating the sun at the top of the atmosphere has been constructed and used to obtain retinal burn thresholds in the rhesus monkey for image diameters corresponding to that of the solar disk on the human retina. Powers incident on the cornea and retinal irradiances required to produce threshold lesions are given for exposure times ranging from 1 s to 3 min. The ocular hazards associated with viewing the sun through aircraft window systems are assessed in terms of these data. Also, radiation in the near infrared is shown to be less dangerous than visible light in producing thermal injury to the retina.
53 citations
TL;DR: Tests included detailed identification and determination of 24- and 48-hr minimal inhibitory concentrations and minimal fungicidal concentrations of 5-fluorocytosine (5-FC) and susceptibility varied amount the different species.
Abstract: One hundred yeasts were studied. Tests included detailed identification and determination of 24- and 48-hr minimal inhibitory concentrations and minimal fungicidal concentrations of 5-fluorocytosine (5-FC). Final identifications included 57 isolates of Candida albicans , 15 isolates of C. tropicalis , 13 isolates of C. parapsilosis , 7 isolates of Torulopsis glabrata , 3 isolates of C. guilliermondii , 2 isolates each of C. stellatoidea and Cryptococcus neoformans , and 1 isolate of Candida krusei . Twenty-three original identifications were in error; these involved mostly C. albicans, C. tropicalis, C. parapsilosis , and T. glabrata . Inhibitory end point readings based on 24 hr of incubation were misleading. Whereas 79 of 91 isolates of Candida appeared to be inhibited at 24 hr by 12.5 μg or less of 5-FC/ml, only 52 were inhibited at 48 hr; whereas only 12 isolates appeared to be resistant to 100 μg/ml after 24 hr, 37 were resistant after 48 hr. Susceptibility varied amount the different species. C. tropicalis was the most susceptible, with 10 of 15 isolates (66.7%) being inhibited by 12.5 μg or less/ml and 7 (46.7%) being killed by 100 μg or less/ml. C. albicans was similarily susceptible; 33 of 57 isolates (57.9%) were inhibited by 12.5 μg or less/ml and 25 (43.9%) were killed by 100 μg or less/ml. C. parapsilosis was quite resistant, as only 4 of 13 isolates (30.8%) were inhibited by 12.5 μg or less/ml and 3 (23.1%) were killed by 100 μg or less/ml.
44 citations
TL;DR: Two theoretical models have emerged to account for variations in the response to imprisonment among inmate populations as discussed by the authors, the "deprivation model" focuses attention on the pressures and deprivat...
Abstract: Two theoretical models have emerged to account for variations in the response to imprisonment among inmate populations. One, the “deprivation model,” focuses attention on the pressures and deprivat...
42 citations
38 citations
TL;DR: Findings indicate that cirrhotic patients are not predisposed to develop cholesterol gallstones and that the bile of patients with cirrhosis was entirely normal (no insoluble cholesterol) and had a greater cholesterol holding capacity than the biliary of control subjects.
36 citations
TL;DR: The production of the sporulation pigment on glucose-salts-agar was comparable to that obtained on tomato paste-oatmeal-agar medium, and among the nitrogenous substances tested, KNO(3) was most desirable for pigmentation.
Abstract: Streptomyces venezuelae S13 produced a pH-indicating sporulation pigment on a glucose-salts-agar medium consisting of glucose, KNO(3), MgSO(4), and Na(2)HPO(4), pH 7. Pigmentation on this medium appeared to be closely associated with sporulation, which normally required 5 to 7 days at 30 C. The pigment was soluble in water as well as in a number of organic solvents. Butanol-extracted pigment exhibited absorption maxima at 430 and 520 nm at pH 3 and 12, respectively. Although many salts of organic acids and amino acids could replace glucose as the sole carbon source in basal salts-agar medium for growth and pigmentation, most sugars that were tested supported good growth but negligible pigmentation. Among the nitrogenous substances tested, KNO(3) was most desirable for pigmentation. The organism did not exhibit any specific requirements for divalent cations with respect to growth and pigmentation. In the absence of MgSO(4), however, glucose-salts-agar prepared by autoclaving all components together failed to support growth. The production of the sporulation pigment on glucose-salts-agar was comparable to that obtained on tomato paste-oatmeal-agar medium. Incorporation of partially purified pigment material into broth medium that did not normally support sporulation induced sporulation, and amino acid-salts-agar medium could induce vegetative mycelia to pigment when transferred from medium that did not support either pigmentation or sporulation.
Patent•
09 Oct 1973TL;DR: In this paper, a triester triester containing at least one mole of a hydroxymethyl bicyclic phosphate and 0-2 moles of a phenyl or naphthyl aryl compound was used as the sole flame-retardant additive or a two-component additive comprising the triester in admixture with 20 to 80 percent of certain polychlorinated or polybrominated diaryl compounds.
Abstract: Flame-retardant polyester fibers containing 5 to 20 percent by weight of phosphate triester containing at least one mole of a hydroxymethyl bicyclic phosphate and 0-2 moles of a phenyl or naphthyl aryl compound as the sole flameretardant additive or a two-component additive comprising the aforesaid triester in admixture with 20 to 80 percent of certain polychlorinated or polybrominated diaryl compounds.
TL;DR: It is concluded that alpha thalassemia may be easily detected through MSCV and MCH screening of newborn populations at risk.
TL;DR: Examination of the differential prestige accorded various medical specialities by practicing physicians in a metropolitan medical community is provided and the implications for intra-occupational interaction and organizational change are explored.
TL;DR: Hb Leiden participates to the same extent as does Hb A in gelation with deoxy Hb S and has a slightly higher oxygen affinity in 0.1 M Phosphate, a normal Bohr effect but an abnormal response to 2,3 diphosphoglycerate and inositol hexaphosphate.
Journal Article•
TL;DR: Pretreatment of mice with multiple doses of Escherichia coli endotoxin resulted in a significant reduction in the lethality of 6-mercaptopurine- or vincristine-endotoxin combinations, but had no influence on 5-fluorouracil- or methotrexate-endOToxin combinations.
Abstract: The toxicity of Salmonella typhosa 0901W endotoxin to mice was potentiated by (per kilogram) 1 mg of colchicine, 20 mg of emetine, 100 mg of 6-mercaptopurine, 100 mg of 6-methylmercaptopurine riboside, 75 mg of methotrexate, 2 mg of sparsomycin, or 2.5 mg of vinblastine. No potentiation of endotoxin lethality was evident with simultaneously administered (per kilogram): 200 mg of cytosine arabinoside, 450 mg of dibromomannitol, 100 mg of 5-fluorouracil, 125 mg of 5-fluorouracil deoxyriboside, 8 mg of mitomycin C, 1 mg of nitrogen mustard, or 10 mg of tris(1-aziridinyl)-phosphine sulfide. With the exception of colchicine, all drugs prolonged the duration of sleep after the administration of 80 mg of hexobarbital per kg. Simultaneous injection of endotoxin with 100 mg of 6-mercaptopurine per kg, 75 mg of methotrexate per kg, or 1 mg of vincristine per kg resulted in significantly greater lethality than administration either prior to or after the drug. However when endotoxin was administered prior to 100 mg of 5-fluorouracil per kg, lethality was significantly increased. The route of administration of endotoxin and 5-fluorouracil, 6-mercaptopurine, methotrexate, or vincristine did not influence overall lethality. Pretreatment of mice with multiple doses of Escherichia coli endotoxin resulted in a significant reduction in the lethality of 6-mercaptopurine- or vincristine-endotoxin combinations, but had no influence on 5-fluorouracil- or methotrexate-endotoxin combinations. Endotoxin-pretreated mice were more susceptible to vincristine alone and more resistant to high doses of 5-fluorouracil. The lethality of 6-mercaptopurine was increased by simultaneous administration of gram-negative isolates from feces of human patients with neoplastic disease.
TL;DR: In this article, behavioral measures of personal space were taken on 102 fifth and sixth grade children, each of whom was assigned to one of three groups: (a) Model-Close condition, (b) Model Far condition, and (c) No-Model Control condition.
Abstract: Summary Approach vs. be approached behavioral measures of personal space were taken on 102 fifth and sixth grade children, each of whom was assigned to one of three groups: (a) Model-Close condition, (b) Model Far condition, and (c) No-Model Control group. A male peer served as model (M), and a 41-year-old female served as the object person. Results revealed a strong modeling tendency with both girls and boys tending to stay close or far from the object person as a function of M behavior. Boys and girls tended to behave similarly in the Close and Far modeling groups, but girls used more space in the No-Model Control condition. These findings suggest that modeling had an attenuating effect on sex differences in use of space. It was concluded that modeling theory is a viable conceptual tool for use in personal space research.
TL;DR: Fractionation reduced the final degree of lens opacification by a factor of 2 or less, depending upon the dose and type of radiation.
Abstract: Opacification of the rabbit lens was studied as a function of dose and time post irradiation for single and fractionated doses of 1 MeV X-rays, 20 and 100 MeV protons. The degree of opacification was found to be a function of time, radiation dose, LET and mode of dose deliverance. Fractionation reduced the final degree of lens opacification by a factor of 2 or less, depending upon the dose and type of radiation.
TL;DR: Saliva flow, protein concentration, and blood group substance concentration in the whole saliva of 106 persons were compared and some of these variables then were compared with age, decayed surfaces, DMF surfaces, and immunoglobulin concentration.
Abstract: Saliva flow, protein concentration, and blood group substance concentration in the whole saliva of 106 persons were compared. Some of these variables then were compared with age, decayed surfaces, DMF surfaces, and immunoglobulin concentration (IgA and IgG).
TL;DR: In this article, the chemical modification of the quadrupole interaction of supported α-Fe 2 O 3 microcrystallites with H 2 S and H 2 O was investigated in both the oxidized and the reduced states.
TL;DR: The female American cockroach undergoes harmonious cycles of ingestion and elimination during the 6-day vitellogenic cycle, and under dessicating conditions the female cockroach is able to reduce water loss by regulation of transpiration.
TL;DR: The authors investigated how individuals are perceived as a function of their association with others and found that an unattractive male was perceived in a more favorable light when he was paired with an attractive female.
Abstract: The present study investigated how individuals are perceived as a function of their association with others. An unattractive male was perceived in a more favorable light when he was paired with an ...
TL;DR: An unusual case of hepatitis following repeated surreptitious administration of halothane was studied, and necrosis and ballooning of liver cells in central areas without nuclear unrest and with minimal inflammatory activity were shown.
Abstract: An unusual case of hepatitis following repeated surreptitious administration of halothane was studied. Light microscopy showed necrosis and ballooning of liver cells in central areas without nuclear unrest and with minimal inflammatory activity. Electron microscopy showed cell shrinkage with dark-staining liver cells, myelin-like figures, enlargement of the intercellular space and intercellular villus formation. The balloon cells contained large intracellular areas free of organelles. Mitochondria appeared quite well preserved, even in areas adjacent to intracellular ballooning. Some cells contained bundles of fibrillar material. The pattern of injury appears to be largely nonspecific.
TL;DR: There is considerable theoretical and empirical evidence that proximity to an emergency event increases the probability that helping behavior will occur as discussed by the authors, and the relationship between physical proximity to emergency and helping behavior may be explained in terms of physiological arousal.
Abstract: There is considerable theoretical and empirical C:11nnn....+ +n.-r+’ho lwmnthn.-~ +’h_+ _’h--r..-&dquo;: _....1 su-ort for the hy-,othes4-s that pll-~ys,4,ca’L --1’1’-’&’’’’’ .&..V’.&. &dquo;&dquo;’£&.’&dquo; £&.J 1’’&dquo;’ &dquo;&dquo;J.&,,&dquo;,ü..l...;J B..JAg.B.. J:1J1] ;:J..L’-Q..L proximity to an emergency event increases the probability that helping behavior will occur. The disruption of accustomed patterns of interaction associated with involvement in natural disaster situations has been credited with the strengthening of primary group life (Fritz, 1961, p. 690) and causing &dquo;the reconstitution of a Gemeinschaft, a &dquo;community&dquo; (1967, p. 8) or, as Turner puts it, &dquo;a resurgence of mechanical solidarity&dquo; (1966, p.3). Increased social interaction in response to the threat posed by disasters may be compared to the social consequences of conflict with out-groups (cf. Simmel, 1955; Coser, 1956), and has been reported to result in &dquo;a phenomenal increase in acts of altruism&dquo; (Shaskolsky, 1967, p. 8) among those surviving the emergency (Wallace, 1956, p. 124; Moore, 1958, p. 313). According to equity theory, the relationship between physical proximity to emergency and helping behavior may be explained in terms of physiological arousal. Distress is produced in bystanders by inequitable arrangements, and the arousal thus elicited
TL;DR: In this paper, the pyridine adduct of n-butyltrichlorostannane with 2,4-pentanedione in the presence of polypyridine was identified.
TL;DR: Pactamycin rendered the mice more susceptible to endotoxin and that endotoxin was the causal lethal agent, and Prednisolone pretreatment alleviated the toxicity of the combination.
Abstract: Combinations of pactamycin and Salmonella typhosa 0901 endotoxin, administered simultaneously, killed more BALB/c mice than comparable doses of either agent alone The slopes of the dose-response curves for combinations of endotoxin and pactamycin were parallel to both that for endotoxin alone and the antitumor drug alone; therefore, no new mechanism of toxicity has been evoked by the combination. The synergistic toxicity of endotoxin and pactamycin was due to an in vivo interaction rather than a direct reaction between the two agents. Phenobarbital pretreatment protected the mice from toxicity of the antitumor agent alone but not from the lethal action of the combination. Pretreatment with endotoxin increased the resistance of the mice to both endotoxin alone and the combination. Third agents unable to protect mice from the synergistic toxicity of endotoxin and pactamycin were alpha[p-(fluoren-9-ylidenemethyl)-phenyl]-2-piperidine-ethanol, neomycin, phenylbutazone, polymyxin B, and tybamate. Prednisolone pretreatment alleviated the toxicity of the combination. For the restricted series of killed bacteria and bacterial products tested for capability to enhance the toxicity of pactamycin, only gram-negative bacterial cells were potent. These results indicated that pactamycin rendered the mice more susceptible to endotoxin and that endotoxin was the causal lethal agent.
TL;DR: The cockroaches' ability to hyporegulate their blood is discussed with relation to possible mechanisms of salt and water balance in insects.