Showing papers by "Clemson University published in 1980"

Maternal Reactions to Involuntary Fetal/Infant Death

Abstract: (1980). Maternal Reactions to Involuntary Fetal/Infant Death. Psychiatry: Vol. 43, No. 2, pp. 155-159.

Litterfall, stemflow, and throughfall nutrient fluxes in an alluvial swamp forest.

Abstract: Nutrient deposition to the forest floor of an alluvial swamp in the North Carolina Coastal Plain was measured and compared with other wetland and upland forests. For the alluvial forest, annual litterfall was 6428 kg dry mass/ha of which 63% was Nyssa aquatic leaves. Nutrient flux to the forest floor in kilograms per hectare per year for litterfall and aqueous sources (stemflow plus throughfall), respectively, was 2779 and 91.5 for organic carbon, 72.77 and 10.31 for N, 5.38 and 1.55 for P, 7.19 and 9.21 for S, 21.1 and 11.96 for K, 45.1 and 15.31 for Ca, and 17.0 and 7.60 for Mg. Most of these values are near the upper range or higher than those reported for mature upland temperate forests and still-water swamps. The particularly high values for nitrogen and phosphorus in the alluvial forest may be a consequence of fluvial sources, whereas nutrient sources for upland forests and still-water swamps are restricted to atmospheric inputs and weathering.

Relations between d-ribulose-1,5-bis-phosphate carboxylase, carboxysomes and co2 fixing capacity in the obligate chemolithotroph thiobacillus-neapolitanus grown under different limitations in the chemostat

Abstract: An adaptation of the d-ribulose-1,5-bisphosphate carboxylase (RuBPCase) activity to changing CO2 concentrations in the growth medium in the chemostat was observed in the obligate chemolithotroph Thiobacillus neapolitanus. RuBPCase activity has been separated in a soluble and particulate fraction. The activity of the particulate fraction appeared to be associated with the carboxysomes.

Enumeration of Bacteriophages and Host Bacteria in Sewage and the Activated-Sludge Treatment Process

Abstract: Bacteriophage populations in an activated-sludge sewage treatment plant were enumerated. A newly developed assay for quantitation of total phages, employing direct electron microscopic counts, was used in conjunction with the plaque assay. The total concentration of phages was significantly higher in reactor mixed liquor and effluent than in influent sewage, indicating a net production of phages within the reactor. Maximum total phage concentrations in the fluid phase of sewage, activated-sludge mixed liquor, and reactor effluent were 2.2 × 107, 9.5 × 107, and 8.4 × 107/ml, respectively. Conditions were optimized for isolation of predominant heterotrophic aerobic bacteria from sewage and mixed liquor. Blending at ice water temperatures was superior to ultrasound or enzyme treatments for maximum release of viable bacteria from microbial floc. A solidified extract of mixed liquor was superior to standard media for cultivating maximum numbers of heterotrophic bacteria. The highest culture counts for sewage and mixed liquor were 1.4 × 107 and 1.3 × 109/ml, respectively, which represented only 3 and 6.8% of the total microscopic cell counts. Only 3 out of 48 dominant bacterial isolates from either mixed liquor or sewage were hosts for phages present in the system. The sum of phage populations infecting these three hosts accounted for, at best, 3.8% (sewage) and 0.2% (mixed liquor) of the total number of phages present. Generally, specific phage titers were lower in mixed liquor than in sewage, indicating that these hosts were not responsible for the net production of phages in the reactor. This study emphasizes the limitations of the plaque assay for ecological studies of phages, and it suggests that bacteria responsible for phage production in activated-sludge mixed liquor are either minor components of the heterotrophic population, floc-producing strains, or members of other physiological groups.

Purification of peach polyphenol oxidase in the presence of added protease inhibitors

Abstract: Crude preparations of peach fruit (Prunus persica Batsch cv. Redskin) polyphenol oxidase (PPO) showed many apparent isoenzyme forms. Some of these forms were probably the result of proteolytic action of peach proteases while other forms were the result of association of PPO with carbohydrate materials. In the presence of protease inhibitors, Trasylol and phenylmethylsul-fonyl fluoride, three apparent isoenzyme forms of PPO were purified to homogeneity. The purification scheme included hydrophobic chromatography on phenyl sepharose CL-4B, hydroxylapatite chromatography, DEAE cellulose chromatography, and gel filtration on Ultrogel AcA 34. Minor contaminants remaining after these steps were separated from PPO by gel electrophoresis. The major PPO isoenzyme form (A) was purified 44 fold with an overall yield of 5.6% and contained no detectable carbohydrates. Isoenzyme forms A' and A' were purified 104 and 67 fold respectively, but still were associated with carbohydrate material. Cesium chloride centrifugation partially removed the carbohydrates associated with PPO A' and A'. Purified peach PPO A showed greater activity toward D-catechin (539%) and pyrogallol(l82%) than to catechol (100%). An apparent K3 of 4, 0.3, and 2 mM was obtained with D-catechin, pyrogallol and catechol, respectively. The enzyme was severely inhibited by 10 μM 2,3-naphthalenediol (91%) and by 10 pM diethyl dithiocarbamate (100%).

Growth inhibition of cultured fibroblasts by cobalt and nickel.

Abstract: It is known that tissues surrounding the site of an implanted prosthetic alloy are exposed to increased concentrations of the metals comprising the alloy. However, the exact identity and concentration of such metallic products are usually unknown, thus limiting the possibilities for quantifying any observed toxicological response to the metals. This report describes some of the effects of increased concentrations (7.5-30 microgram/ml; 1-5 x 10(-4)M) Of cobalt (as CoCl2.6H2O) and of nickel (NiCl2.6H2O) on the growth and morphology of cultured mouse fibroblasts. Ultrafiltration experiments indicated that much of the total Co or Ni present in cell culture medium could become bound to macromolecular serum components of the medium. Morphological changes and depressions in the cell growth rate were found to result from high concentrations (15-30 microgram/ml) of either Co or Ni. However, lower concentrations of nickel may have produced some stimulation of cell growth, whereas all concentrations of Co studied were found to depress the rate of cell growth. The growth rate of actively proliferating fibroblasts was quite sensitive to variations in the concentration of either cobalt or nickel. Increased concentrations of cobalt or nickel, therefore, might also affect the normal reconstructive activity of fibroblasts in vivo.

Pyrolysis and combustion of cellulose. VII. Thermal analysis of the phosphorylation of cellulose and model carbohydrates during pyrolsis in the presence of aromatic phosphates and phosphoramides

Abstract: Thermal gravimetric analysis, differential scanning calorimetry, and derivative thermal gravimetric analysis were utilized to characterize the thermal interactions between cellulose, 1-6, anhydro β-D-glucopyranoside, and D-glucose and model phosphate and phosphoramide flame retardants. The phosphoramides induced higher char yields than the phosphates during the pyrolysis of the mixtures of carbohydrates and organophosphorus compounds. Exothermic reactions attributed to phosphorylation and char formation were observed with each of the phosphoramide/carbohydrate mixtures and were absent with the phosphates. The individual phosphorus compounds studied showed similar thermal behavior with each of the carbohydrates indicating that the mode of interaction for these mixtures was similar. Isothermal gravimetric analysis of the organophosphorus/carbohydrate mixtures was used to measure the rate of decomposition weight loss from isothermal conditions. This weight loss was used as an indication of rate of fuel formation. The kinetics observed for these measurements indicated that the phosphoramide mixtures underwent a rapid weight loss to a final char with an effective Eact of about 55 kcal/mol while the phosphate mixtures exhibited effective Eact′s for decomposition lower than those observed for the pure carbohydrates. Mixtures of glucose with selcted arylphosphoramide esters were pyrolysed in order to determine the effect of lability of the leaving group on char formation. Gas chromatographic analysis of the pyrolysis products indicated that phenol was the favored leaving group in comparison with aniline units, but char promotion appeared to be dependent on the number of P-N bonds present in the original phosphoramide. Electron spectroscopy for chemical analysis indicated that chemically similar chars were obtained from the different organophosphorus/carbohydrate combinations.

Enrichment of 210Pb and 210Po in the sea-surface microlayer

Abstract: Chemical fractionation at the air–sea interface is frequently suggested1–5 as a possible mechanism contributing to the enrichment of a number of trace metals in the marine atmosphere6,7. The origin of the long-lived radon daughters (210Pb, 210Bi and 210Po) in the atmosphere is of special interest because of their use in the estimation of tropospheric aerosol residence times8. It has been proposed9 that injection of a fractionated marine component by bubbles bursting at the sea surface might be responsible for the occurrence of anomalously high atmospheric 210Po/210Pb ratios in Antarctica10 and Hawaii11. Here we report the first measurements of 210Pb (t1/2 = 22.3 yr) and 210Po (t1/2 = 138 d) in the sea-surface microlayer. These measurements were made to determine whether or not a significant flux of these radionuclides from the sea surface to the atmosphere could occur. We also introduce a method for treating chemical data that we believe may be useful in determining the origin of the trace-metal enrichments often observed1,2 in the microlayer.

Piezoelectric ceramic implants: A feasibility study†

Abstract: A piezoelectric ceramic has been investigated as a direct substitute for hard tissues. Barium titanate (BaTiOz) power was slipcast and fired at 1430 degrees C for 2 hr, then made piezoelectric by polarizing. After 16 and 86 days of implantation in the cortex of the femoral midshafts, the femora with test specimens were sectioned into about 4-cm lengths. Their voltage outputs were measured under cyclic load at 1 Hz. The present results show that the voltage gradient at the implant surface is 0.15 mV/mm for the 16-day implantation with a 445-N (100-lbs.) load. This in turn can give rise to about 0.01 microA current flow in the adjacent area of the 16-day implant. The 86-day implant showed an order of magnitude higher voltage output compared to the 16-day implant with the same magnitude of loads. This is probably due to the "load-transfer" efficiency through the implants, since the voltage output is directly proportional to the actual load transferred to the implant. The more bone implant interface matures, the better the load transfer occurs through the implant, resulting in higher voltage output.

Identification of predaceous arthropods in soybeans by using autoradiography.

Abstract: Field cage experiments were conducted to identify predators which feed on eggs and early stage larvae of Heliothis spp., Pseudoplusia includens (Walker) and Anticarcia gemmatalis Hubner. Isotope labeled (32p) eggs, 1st-, 2nd-, and early 3rd-stage larvae were exposed to possible predators. Predaceous arthropods which obtained the label were identified by autoradiography. A total of 349 individual arthropods from 25 species obtained radioactive labels when exposed to lepidopterous eggs or early stage larvae. Major predators identified in this study were Nabis roseipennis Reuter, Geocoris punctipes (Say), and Oxyopes salticus Hentz. Nabis roseipennis was the most frequently labeled predator of eggs and larvae. Spider species encountered in this study were not labeled when eggs were provided as prey. A high percentage of the carabids found in the foliage such as Lebia analis Dejean, Callida decora (F.) and Colliuris pennsylvanicus (L.) was labeled. Other foliage dwelling beetles which contained the isotope were Coleomegilla maculata (DeGeer) adults and larvae and Notoxus monodon (F.). Several tettigoniids, Conocephalus fasciatus (Forster), also were labeled. Predation upon primary predators was demonstrated when labeled nymphs of G. punctipes and N. roseipennis were exposed to the indigenous predator complex.

Performance of Digital Integrated Circuit Technologies at Very High Temperatures

Abstract: Results of detailed investigations of the performance and reliability of digital bipolar and complementary metal-oxide-semiconductor (CMOS) integrated circuits over the 25-340°C range are reported. Included in these results are both parametric variation information and analysis of the functional failure mechanisms. Although most of the work was done using commercially available circuits (TTL and CMOS) and test chips from commercially compatible processes, some results from experimental simulations of dielectrically isolated CMOS are also discussed. In general, it was found that commercial Schottky-clamped transistor-transistor logic (TTL) and dielectrically isolated, low power Schottky-clamped TTL functioned to junction temperatures in excess of 325°C. Standard gold-doped TTL functioned only to 250°C, while commercial isolated integrated injection logic (l2L) functioned to the range of 250-275°C. Commercial junction-isolated CMOS, buffered and unbuffered, functioned to the range of 280-310+°C, depending on the manufacturer. Experimental simulations of simple dielectrically isolated CMOS integrated circuits, fabricated with heavier doping levels than normal, functioned to temperatures in excess of 340°C. High temperature life testing of experimental, silicone-encapsulated simple TTL and CMOS integrated circuits have shown no obvious lifelimiting problems to date. No barrier to reliable functionality of TTL bipolar or CMOS integrated circuits at temperatures in excess of 300°C has been found.

Populations of methane-producing bacteria and in vitro methanogenesis in salt marsh and estuarine sediments.

Abstract: Most probable numbers (MPNs) of methanogens in various salt marsh and estuarine sediments were determined with an anaerobic, habitat-simulating culture medium with 80% H(2) plus 20% CO(2) as substrate. Average MPNs for the short Spartina (SS) marsh sediments of Sapelo Island, Ga., were maximal at the 5- to 7-cm depth (1.2 x 10/g of dry sediment). Populations decreased to approximately 880/g of dry sediment at the 34- to 36-cm depth. There was no significant difference between summer and winter populations. In tall Spartina (TS) marsh sediments, average populations were maximal (1.2 x 10/g of dry sediment) in the upper 0- to 2-cm zone; populations from the 5- to 36-cm zones were similar (average of 9 x 10/g of dry sediment). Methanogenic populations for TS sediments of James Island Creek marsh, Charleston, S.C., were similar (average of 3 x 10/g of dry sediment) for all depths tested (0 to 22 cm), which was comparable to the trend observed for TS sediments at Sapelo Island, Ga. Sediment grab samples collected along a transect of James Island Creek and its adjacent Spartina marsh had MPNs that were approximately 20 times greater for the region of Spartina growth (average of 10/g of dry sediment) compared with the channel (approximately 5 x 10 methanogens per g of dry sediment). A similar trend was found at Pawley's Island marsh, S.C., but populations were approximately one order of magnitude lower. In vitro rates of methanogenesis with SS sediments incubated under 80% H(2)-20% CO(2) showed that the 5- to 7-cm region exhibited maximal activity (51 nmol of CH(4) g h), which was greater than rates for sediments above and below this depth. SS sediment samples (5 to 7 cm) incubated under 100% N(2) and supplemented with formate exhibited rates of methanogenesis similar to those generated by samples under 80% H(2)-20% CO(2). Replacing the N(2) atmosphere with H(2) resulted in an eightfold decrease in the rate of methanogenesis. In vitro methanogenic activity by TS salt marsh sediments, incubated under 80% H(2)-20% CO(2), was similar for all depths tested (0 to 22 cm). TS sediment samples (0 to 7 cm) supplemented with formate and incubated under 100% N(2) had greater rates of methanogenesis compared with unsupplemented samples.

The use of stimulus control over littering in a natural setting

Abstract: A conventional litter receptacle (55-gallon drum) and a specially designated receptacle consisting of a 55-gallon drum adorned with a plywood "har" were alternated in two areas of a football stadium over a period of four games. A frequency count of several types of litter articles showed that more than twice as many items were deposited within the experimental container than the conventional one (an average of 52.5 and 21.5 items per game, respectively). The weight of litter deposited within each container showed a similar relationship. An average of 0.65 kg of litter per game were deposited within the conventional receptacle compared with an average of 1.3 kg per game for the experimental receptacle.

Effect of lead speciation on toxicity.

Abstract: Limnologists and aquatic toxicologists generally ignore the interactions between metals and ligands in aqueous systems. Chemical considerations often overlooked in metal toxicity bioassays and biogeochemical analyses of aquatic systems include ligand concentrations, pH, oxidation state, complex formation, precipitation and reaction kinetics. Although hardness and alkalinity are occasionally implicated indirectly in some toxicity assays such considerations usually fail to incorporate the metal-ligand reaction mechanisms. Since the biological activity and availability of metals and ligands may be altered by chemical interactions and water systems may have unique chemical constituents, estimates of chemical speciation that incorporate general reaction mechanisms are necessary for accurate assessments of biogeochemical activity. Chemical equilibrium analysis of the interactions of all constituents in the bioassay mixture provides a relatively rapid and inexpensive method for examination of theoretical chemical speciation. If it is assumed that free or uncomplexed forms of the elements are the biochemically active species, experiments can be designed to fit the most important chemical boundary conditions of the reacting mixture. The efficacy of this approach was demonstrated in out experiments on the toxicity of lead in a synthetic medium.

Noether's theorem and Ermakov systems for nonlinear equations of motion

Abstract: We present a simple but important generalization of the use of Noether’s theorem to generate invariants for time-dependent nonlinear equations of motion. Our main result is that Noether’s theorem produces invariants even when the equation of motion contains arbitrary functions. The results obtained by using Noether’s theorem are the most general results for which one obtains explicit nonlinear superposition laws for the class of equations of motion considered. We also correct a recent paper on this same subject.

A new look at numerical analyses of free-edge stresses in composite laminates

Abstract: The edge stress problem for a + or - 45 deg graphite/epoxy laminate was examined. The reliability of the displacement formulated finite element method in analyzing the edge stress problem was investigated. Analyses of two well known elasticity problems, one involving a stress discontinuity and one a singularity, showed that the finite element analysis yields accurate stress distributions everywhere except in two elements closest to the stress discontinuity of singularity. Stress distributions for a + or - 45 deg laminate showed the same behavior near the singularity found in the well known problems with exact solutions. The displacement formulated finite element method appears to be a highly accurate technique for calculating interlaminar stress in composite laminates. The disagreement among the numerical methods was attributed to the unsymmetric stress tensor at the singularity.

General considerations on the design of an interactive system for data analysis

Abstract: Among the most important criteria in the design and implementation of an interactive system for data analysis are: data structure, control language, user interface, sytem versatility, extensibility, and portability. The design of an interactive system, viewed as a set of constrained decisions based on these criteria, will be discussed. The concepts and considerations discussed in this article about the design of interactive systems are general in nature and are neither problem-specific nor discipline-specific. Specific examples from statistical packages and their designs are cited for illustration purposes only.

Pesticide inhibition of the entomogenous fungus Nomuraea rileyi in soybeans.

Abstract: Two applications of the fungicides Benlate®, Du Ter®, and Bravo®, and Benlate in combination with carbaryl were made to soybean. Infection of lepidopterous larvae by the entomogenous fungus Nomuraea rileyi (Farlow) Samson was inhibited to some degree by application of Benlate ®, Du Ter®, and Bravo®. Bravo caused the most inhibition followed by Bentlate and Du Ter respectively. In one instance the combination of Benlate + carbaryl was more disruptive to N. rileyi than either chemical alone. Inhibition was greatest when pesticide application coincided with the early stages of N. rileyi epizootics.

Epr Study of Free Radicals in Pmma Bone Cement: A Feasibility Study

Abstract: In order to determine the feasibility of using electron paramagnetic resonance (EPR) to monitor the molecular processes occurring in polymethylmethacrylate (PMMA) bone cement, a preliminary study has been conducted on the bone cement In vitro.It has been found that a sufficient concentration of free radicals is generated in the bone cement during the polymerization process so that both the polymerization and the curing can be monitored by EPR. The results of these measurements on both radiolucent and radiopaque Surgical SimplexR P bone cement are presented.It has also been found that free radicals are present in the radiopaque bone cement powder as received from the manufacturer. These radicals which apparently are produced in the radiation sterilization process have been found to be unaffected by the polymerization/curing process and to be stable for temperatures below about 100°C.It has clearly been shown that EPR can be used to monitor the molecular processes of bone cement in vitro. It is hoped that t...