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11.
Phosphorus load estimates have been updated for all of the Great Lakes with an emphasis on lakes Superior, Michigan, Huron and Ontario for 1994–2008. Lake Erie phosphorus loads have been kept current with previous work and for completeness are reported here. A combination of modeling and data analysis is employed to evaluate whether target loads established by the Great Lakes Water Quality Agreement (GLWQA, 1978, Annex 3) have been and are currently being met. Data from federal, state, and provincial agencies were assembled and processed to yield annual estimates for all lakes and sources. A mass-balance model was used to check the consistency of loads and to estimate interlake transport. The analysis suggests that the GLWQA target loads have been consistently met for the main bodies of lakes Superior, Michigan and Huron. However, exceedances still persist for Saginaw Bay. For lakes Erie and Ontario, loadings are currently estimated to be at or just under the target (with some notable exceptions). Because interannual variability is high, the target loads have not been met consistently for the lower Great Lakes. The analysis also indicates that, because of decreasing TP concentrations in the lakes, interlake transport of TP has declined significantly since the mid-1970s. Thus, it is important that these changes be included in future assessments of compliance with TP load targets. Finally, detailed tables of the yearly (1994–2008) estimates are provided, as well as annual summaries by lake tributary basin (in Supplementary Information). 相似文献
12.
Ibrahim Greiby Muhammad Siddiq Kirk D. Dolan Shantanu Kelkar 《International Journal of Food Science & Technology》2013,48(5):992-998
Anthocyanins (ACY) and colour changes in cherry pomace under non‐isothermal processing were investigated. Pomace at moisture levels of 70% (MC‐70), 41% (MC‐41) and 25% (MC‐25) was heated at 126.7 °C in a retort for 25, 40 and 60 min. Total ACY, Hunter colour values, total colour difference (ΔE), chroma, hue angle (h°) and browning index (BI) were analysed. Thermal degradation kinetics for colour parameters were determined using zero‐ and first‐order models. ACY degradation increased with heating time and ranged from 34 to 68% for 25 and 60 min heating, respectively. The half‐life of ACY was 38, 33 and 27 min for MC‐70, MC‐41 and MC‐25 pomace, respectively. The ΔE increased with increasing heating time, whereas BI exhibited an inverse trend. Except for ?E for MC‐70, the zero‐order kinetic model showed better fit (R2 = 0.85–0.97) to experimental data than the first‐order kinetic model for Hunter colour b values and ?E. 相似文献
13.
Alonso DO An C Daggett V 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2002,360(1795):1165-1178
As computer power increases, so too does the range of interesting biomolecular phenomena and properties that can be simulated. It is now possible to simulate complicated protein conformational changes at ambient or physiological temperatures. In this regard, we are attempting to map the conformational transitions of the normal, cellular prion protein (PrP(C)) to its infectious scrapie isoform (PrP(Sc)), which causes neurodegenerative diseases in many mammals. These two forms have identical sequences and are conformational isomers, with heightened formation of beta-sheet structure in the scrapie form. Conversion can be triggered by lowering the pH, but thus far it has been impossible to characterize the conformational change at high resolution using experimental methods. Therefore, to investigate the effect of acidic pH on PrP conformation, we have performed molecular-dynamics simulations of hamster, human and bovine forms of the prion protein in water at neutral and low pH. In all cases the core of the protein is well maintained at neutral pH. At low pH, however, the protein is more dynamic, and the sheet-like structure increases both by lengthening of the native beta-sheet and by addition of a portion of the N-terminus to widen the sheet by another 2-3 strands. 相似文献
14.
Experimental data from protein engineering studies and NMR spectroscopy have been used by theoreticians to develop algorithms for helix propensity and to benchmark computer simulations of folding pathways and energy landscapes. Molecular dynamic simulations of the unfolding of chymotrypsin inhibitor 2 (CI2) have provided detailed structural models of the transition state ensemble for unfolding/folding of the protein. We now have used the simulated transition state structures to design faster folding mutants of CI2. The models pinpoint a number of unfavorable local interactions at the carboxyl terminus of the single alpha-helix and in the protease-binding loop region of CI2. By removing these interactions or replacing them with stabilizing ones, we have increased the rate of folding of the protein up to 40-fold (tau = 0.4 ms). This correspondence, and other examples of agreement between experiment and theory in general, Phi-values and molecular dynamics simulations, in particular, suggest that significant progress has been made toward describing complete folding pathways at atomic resolution by combining experiment and simulation. 相似文献
15.
CT Furstenberg TA Ahles MB Whedon KL Pierce M Dolan L Roberts PM Silberfarb 《Canadian Metallurgical Quarterly》1998,15(6):335-349
The knowledge and attitudes toward cancer pain management of physicians, nurses, and pharmacists in the state of New Hampshire were examined through the use of a statewide survey. Many of the providers who completed the survey, and thus indicated that they treated patients with cancer pain on a regular basis, were not pain or oncology specialists. Most of these providers were quite well informed about the fundamentals of cancer pain management. Approximately 90% of providers in all three groups were not concerned about addiction among cancer patients. Yet, there was a small percentage of providers who responded in less than optimal ways to items dealing with opioid pharmacology, pain assessment, and the importance of pain relief. Comparison of responses among provider groups indicated that nurses were the most knowledgeable and pharmacists the least knowledgeable about pain assessment. Physicians were the most knowledgeable regarding opioid pharmacology but seemed the least committed to providing optimal pain relief. Further analysis identified a small group of physicians that included a disproportionately high percentage of family practitioners and surgeons who consistently responded in less than optimal ways to items dealing with the importance of pain relief. The results of this study indicate a continuing need for broad-based educational programs in cancer pain management and for new initiatives focused on practitioners who see relatively few cancer patients and may have difficulty accessing traditional educational programs. 相似文献
16.
This prospective study examined the predictive validity of the Structured Assessment of Violence Risk in Youth (SAVRY) and the Psychopathy Checklist: Youth Version (PCL: YV) in 99 male adolescents who were assessed in custody and followed up 12 months post release. Outcome data on recidivism were based on official Home Office records. The base rates for violent and general recidivism, respectively, were 38.4% and 70.7%. The predictive validity of the SAVRY Risk Total and the SAVRY Risk Rating was moderate for both violent and general recidivism, but both showed incremental validity in predicting outcomes compared with the PCL: YV. Data are discussed in relation to the limited published international literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
The misfolding and aggregation of the prion protein (PrP) is the primary cause of a group of infectious neurodegenerative
diseases including Creutzfeldt-Jacob disease in humans and Bovine Spongiform Encephalopathy in cows. A single disease can
exhibit different infectious strains distinguishable by incubation time and morphology or distribution of the aggregates.
Infected brain tissue from one species can be used to infect other species, but with different efficiencies, suggesting a
spectrum of species compatibility. If PrP is, as widely believed, the sole component of infection, then the species and strain
differences must be accounted for by the structure of the aggregates, likely influenced by each species’ PrP sequence. As
there are no high-resolution data exploring this hypothesis, we performed molecular dynamics simulations of PrP for human,
bovine, hamster, and D147N mutant hamster sequences at low pH to induce misfolding of the protein. We selected representative
converted structures from each of the four sequences and, with the guidance of experimental data, constructed models of the
infectious aggregates. Both hamster monomers showed high flexibility during conversion, suggesting hamster may more easily
adopt altered conformations, which in turn may explain why it is more easily infected by some other species. Human and bovine
aggregates were similar, with monomers docking in P31 symmetry to form a left-handed spiral. In contrast, hamster aggregates formed a P31 right-handed spiral. We detail the differences in the converted monomers that give rise to this difference and show that
our results compare favorably with experimental data.
This paper is part of the special Journal of Materials Science issue Nano- and micromechanical properties of hierarchical biological materials: Linking mechanics, chemistry and biology; Guest
Editor: Markus J. Buehler that appeared in Journal of Materials Science volume 42, issue 21, November 2007. This paper was delayed for nonscientific
reasons. 相似文献
18.
The dry hot syngas cleaning process appears to be potentially more efficient and cleaner than the proven wet cleaning or semi-wet cleaning processes but it is still far from commercialisation. There are several technological barriers responsible such as poor availability factor, degeneration of sorbent and several stages of separation. This paper summarises the reported current status of dry hot cleaning of syngas from coal gasification processes along with the shortcomings of reporting of dry hot syngas cleaning performance results. The paper also proposes and discusses a rational method of performance reporting, a novel pulse less filtration concept and a system to prevent failure of filter elements. 相似文献
19.
A method for the determination of the fermentability of unboiled, filtered, malt Hot Water Extracts has been developed. The wort is fermented under carefully controlled conditions, using fresh distillers' yeast. Knowledge of a malt's extract and fermentability allows calculation of its fermentable extract content, which allows spirit yield prediction, and the method is in use as a basis for Malt Purchase Specifications. 相似文献
20.
Dolan Michael P.; Black John L.; Penk Walter E.; Robinowitz Ralph; DeFord Horace A. 《Canadian Metallurgical Quarterly》1985,53(4):549
Evaluated the effectiveness of a contingency contracting intervention on reducing illicit drug use by 21 25–60 yr old male methadone maintenance patients selected on the basis of positive urinalysis results during a 60-day baseline. The intervention consisted of a 30-day contract, which stated that Ss would continue to receive a specified dosage of methadone, would not be asked to leave the program or detoxify, and would not use illicit drugs during the contract period. Illicit drug use was significantly reduced during the 30-day intervention and remained below baseline levels during a 60-day follow-up. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献