Effects of pH on the bioconcentration of pyrene in the larval midge, Chironomus riparius

Bioconcentration, depuration and biotransformation of the polycyclic aromatic hydrocarbon, pyrene, were studied at pH 4, 6 and 8 with larval stages of the chironomid midge, Chironomus riparius. ¹⁴C-labelled pyrene was applied. The results revealed pH-dependant bioconcentration and depuration-kinetics as well as biotransformation of pyrene. At higher pH the bioconcentration rate (k₁) was greater than at lower pH. Hereby the bioconcentration rate correlated with the accumulation potential of pyrene. That means at pH 8 the larvae accumulated pyrene strongest, at pH 4 the bioconcentration of the larvae was lowest. Due to biotransformation of pyrene the calculated bioconcentration factor (BCF) based on total ¹⁴C found in the larvae. Depuration revealed a biphasic kinetic. Data were fit with a two compartment model to calculate the volume of each of the two compartments. To calculate for the depuration rate (k₂), data were additionally fit with a one compartment model. The larvae displayed an intriguing pH-dependent behaviour: At pH 4 the Chironomus larvae started to increase mucus-production of the salivary glands and accelerated the built up of their tubes. The latter were of “cocoon”-like structure. At pH 8 the composition of the tubes was more loose. It is hypothezised that this response to an acidified environment caused the reduced bioconcentration rate as well as the reduced biconcentration.     

Korrosionsschutz durch Auftragschweißen mit den reaktiven Metallen Titan,Tantal und Zirkonium

Corrosion protection using surface-welded titanium, tantalum and zirconium claddings Very stringent demands are imposed on the corrosion resistance properties of components, apparatus, and plants of the chemical industry as well as in apparatus and machine construction. For technical and economic reasons, composite-layer materials which withstand the mechanical and corrosive conditions are employed. The special-purpose metals, titanium, tantalum, and zirconium exhibit high resistance to corrosion by many aggressive media, even at high pressure and temperature; these properties are not achieved by any of the conventional corrosion-resistant materials under the same conditions. The object of the research work was to develop a basis for producing claddings of titanium, tantalum, and zirconium by weld surfacing on a base metal of different composition with the application of the PHS method. Within the scope of the present project, single-layer claddings were applied by PHS weld surfacing with the use of titanium, tantalum, and zirconium of high purity as cladding materials on intermediate layers of nickel and copper, or alloys of these plasma hot wire weld surfacing, titanium, tantalum, zirconium, dilution, intermetallic phases, bonding, ductility elements. Boiler plate HI1 was employed as substrate for the three-layer composite materials. The titanium claddings thus applied have been thoroughly examined by metallographic techniques, layer analysis, and corrosion chemistry. The results indicate the possibility of producing corrosion-resistant claddings of titanium by the PHS method, provided that the welding process is shielded against contamination by atmospheric gases, and the formation of undesirable reaction products in the bonding zone between the base metal and filler material is minimized by means of an intermediate layer. The corrosion resistance of the surface-welded titanium claddings on an intermediate nickel layer coincides extensively with that of the reference material. On the basis of the corrosion analyses, the surface-welded titanium cladding on an intermediate copper layer is not resistant to corrosion. The results of weld surfacing with titanium have been applied to heterogeneous PHS weld surfacing with the special purpose metals tantalum and zirconium. In principle, metallographic examinations verify the possibility of producing a flawless bond between a cladding of zirconium and an intermediate nickel layer. In comparison with the filler material, Zr 702, however, the zirconium claddings applied by PHS weld surfacing exhibit a considerably greater hardness and low ductility. Because of the large difference between the melting points of tantalum and the substrate material, claddings of this kind cannot be reproducibly manufactured with sufficient quality by the PHS method, since the necessary parameters are at the extreme limit of the feasible range as far as the heat transfer is concerned.     

Synthetic carbonaceous fuel and feedstock using nuclear power,air and water

Development of synthetic carbonaceous fuels and feedstocks (SCFF) is imperative if the U.S. is to maintain its world leadership. Nuclear power can provide not only the stationary thermal and electrical power backbone in the country but can also be of great assistance in supplying SCFF. All forms of carbonaceous materials can serve as sources of raw material for SCFF, however, here we consider the ultimate renewable resource of carbon which is CO₂ from the atmosphere or the oceans. A number of methods for the recovery of CO₂ have been examined. An absorption-stripping system utilizing dilute carbonate solvent appears most economical for atmospheric recovery while distillation appears of interest for sea-water recovery. An alternative isothermal process utilizing chlor-alkali cells is also described. Electrolytic hydrogen is thermocatalytically combined with the CO₂ to form methanol which can then be dehydrated to gasoline. Production cost is dominated by the energy for hydrogen and the plant capital investment. Base loaded nuclear power plants supplying peaking load and generating SCFF in an off-peak mode is proposed for reducing costs. Under 1974/5 conditions, incremental power costs would have been a minimum. Under 1985 escalated conditions, incremental costs indicate 6 mills/kWh(e) for power which yields 33.9 c/gallon methanol or 77.1 c/gallon of equivalent gasoline which takes credit for oxygen would break even with $23/bb1 of oil. The capital investment for producing the equivalent of one million barrels/day of gasoline in 142 nuclear reactors of 100 MW(e) capacity, operating in an off-peak mode, amounts to slightly more than the investment in new oil exploration and production facilities and considerable less than the projected outflow of capital to foreign OPEC countries. The nuclear synthesis-route using atmospheric and aquatic CO₂, simulates the solar photosynthetic process and provides a long-term renewable and environmentally acceptable alternate source of SCFF.     

Gender and haplotype effects upon hematological manifestations of adult sickle cell anemia

We evaluated the rates of short-term neonatal complications, neonatal brain damage or mortality in a group of 96 singleton pregnancies complicated by hypertension and electively delivered before 36 weeks gestation. The neonatal outcome of these pregnancies was compared with that of a matched control group of 192 uneventful pregnancies delivered because of spontaneous preterm labor or premature rupture of membranes. Although the rates of acidosis, apneoic crises, bradycardia and ventilatory support were higher among cases than controls, the risk of intraventricular hemorrhage, severe brain damage (grade III-IV intraventricular hemorrhage or periventricular leucomalacia) or neonatal mortality were comparable between the two groups. Neonatal complications were more frequent among infants born to mothers with severe hypertension or severe proteinuria. In conclusion, this study has shown that short term neonatal complications after elective preterm delivery in hypertensive pregnancies are increased in comparison with low risk controls. However, these complications, which were well managed in our intensive care nursery, did not affected neonatal mortality or severe brain damage.     

Costs and charges associated with three alternative techniques of hysterectomy

BACKGROUND: Many hysterectomies are now performed by a laparoscopically assisted vaginal technique. This procedure is controversial, partly because of concern about cost. We studied hospital charges and costs for the procedure as compared with those for total abdominal hysterectomy and total vaginal hysterectomy in clinically similar groups of patients. METHODS: From hospital-discharge data and patients' charts, we identified hysterectomies performed in 1993 and 1994 by 96 surgeons at a community teaching hospital to treat benign conditions. The patients were grouped according to the surgical procedures performed in conjunction with the hysterectomy. Data on hospital charges and cost-to-charge ratios for 64 hospital cost centers were used to assess charges and costs for specific resources, as well as for the hospitalization overall. RESULTS: Of 1049 patients studied, 26 percent underwent laparoscopically assisted vaginal hysterectomy, 54 percent underwent abdominal hysterectomy, and 20 percent underwent vaginal hysterectomy. The average hospital stays were 2.6, 3.9, and 2.9 days, respectively, and the mean total charges (facility charges plus professional fees) for the hospitalizations were $6,116, $5,084, and $4,221 (P<0.001 for the comparison of the laparoscopic technique with both other techniques). The mean facility costs were $4,914, $3,954, and $3,116, respectively (P<0.001 for the same comparison), with similar findings in all subgroups. The higher charges and costs for laparoscopically assisted vaginal hysterectomy were due to higher supply costs, particularly when disposable supplies were used, and to longer operating-room time. CONCLUSIONS: Despite shorter hospital stays, in-hospital charges and costs for laparoscopically assisted vaginal hysterectomy are higher than for either alternative procedure, because of the disposable supplies that are typically used and the longer operating-room time.     

Early temperamental antecedents of adult Type A behaviors.

Examined the role of early childhood temperament in the development of adult Type A (coronary prone) behaviors, using data on 108 young adults from the ongoing New York Longitudinal Study (begun by A. Thomas and S. Chess in 1956). The data included measures of temperament derived from interviews conducted with the children's mothers when the youngsters were 3 and 4 yrs of age and measures of Type A behaviors derived from interviews conducted with the participants during young adulthood (mean age 21 yrs). Correlational and regression analyses indicated that early childhood temperament accounted for approximately 20% of the variance in achievement-striving, 13% of the variance in impatience-anger, and 15–25% of the variance in overall Type A behavior scores. Achievement-striving in young adulthood was associated with high adaptability and negative mood during early childhood, whereas impatience-anger had as its antecedents low sensory threshold, low persistence, and low adaptability. Findings suggest that certain temperamental attributes, visible early in childhood, may predispose individuals toward the development of the Type A behavior pattern. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anti-DNA, anti-deoxyribonucleoprotein and rheumatoid factor measured by ELISA in patients with systemic lupus erythematosus, Sj?gren's syndrome and rheumatoid arthritis

Serum concentrations of anti-DNA and anti-deoxyribonucleoprotein (NP) antibodies were measured in parallel by standardized ELISA methods with a polyvalent anti-immunoglobulin conjugate in patients with systemic lupus erythematosus (SLE), Sj?gren's syndrome (SS) and rheumatoid arthritis (RA). High levels of these antibodies predominated in systemic lupus erythematosus. While an appreciable incidence of antibodies also occurred in SS and RA, they were mostly at lower levels. By using heavy chain-specific anti-immunoglobulin conjugates, IgG antibodies to both DNA and NP were found in SLE more frequently and at higher levels than were IgM antibodies. In contrast, IgM antibodies to DNA and NP predominated in SS and RA. The immunoglobulin class of the anti-DNA and anti-NP responses in a given SLE patient were not infrequently different. For example, a patient might show a very high IgG but low IgM anti-DNA value, with the reverse being true for anti-NP. IgG anti-DNA antibodies were significantly associated with depressions of C3. During changes in SLE serology, normalization of DNA binding by Farr radioimmunoassay and/or complement was most frequently associated with normalization of the IgG anti-DNA antibody concentrations. In patients simultaneously possessing elevated levels of anti-DNA, anti-NP and rheumatoid factor (RF), absorption with aggregated human IgG usually decreased only the RF activity. In some, however, such absorption decreased all three antibody values simultaneously. The latter findings support observations that some RF possess antinuclear properties.     

Channel simulation and coding with side information

Studies the minimum random bit rate required to simulate a random system (channel), where the simulator operates with a given external input. As measures of simulation accuracy the authors use both the variational distance and the d¯ distance between joint input-output distributions. They find the asymptotic number of random bits per input sample required for accurate simulation, as a function of the distribution of the input process. These results hold for arbitrary channels and input processes, including nonstationary and nonergodic processes and do not hinge on a specific simulation scheme. A by-product of the analysis is a general formula for the minimal achievable source coding rate with side information     

Microwave imaging of aircraft

Three methods of imaging aircraft from the ground with microwave radar with quality suitable for aircraft target recognition are described. The imaging methods are based on a self-calibration procedure called adaptive beamforming that compensates for the severe geometric distortion inherent in any imaging system that is large enough to achieve the high angular resolution necessary for two-dimensional target imaging. The signal processing algorithm is described and X-band (3-cm)-wavelength experiments demonstrate its success on commercial aircraft flying into Philadelphia International Airport.<>