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61.
Anaerobic lagoons and treatment wetlands are used worldwide to treat wastewater from dense livestock production facilities; however, there is very limited data on the hormonal activity of the wastewater effluent produced by these treatment systems. The objectives of this experiment were to measure (1) the hormonal activity of the initial effluent and (2) the effectiveness of a lagoon-constructed wetland treatment system for producing an effluent with a low hormonal activity. Wastewater samples were taken in April, July, and November 2004 and July 2005 from a lagoon-constructed wetland system at a swine farrowing facility. Estrogenic activity (in vitro E-screen assay), 17 beta-estradiol (E2), and testosterone concentrations (LC/MS-MS) were measured. A high correlation was found between estradiol equivalents determined by E-screen and LC/MS-MS (R2 = 0.82). Nutrient removal was measured to ensure that the wetlands were functioning in a manner similar to literature reports. Nutrient removals were typical for treatment wetlands: TKN 59-75% and orthophosphate 0-18%. Wetlands decreased estrogenic activity by 83-93%. Estrone was the most persistent estrogenic compound. Constructed wetlands produced effluents with estrogenic activity below the lowest equivalent E2 concentration known to have an effect on fish (10 ng/L or approximately 37 x 10(-12) M).  相似文献   
62.
A gel filtration chromatographic method has been developed which is capable of fractionating amylose and amylopectin in starch. Three GFC columns (2 × 4000 A and 1 × 300A PL Separation Sciences, Polymer Laboratories Ltd,) are used in series using sodium chloride solution as eluent. Minimal sample preparation is involved which includes a preliminary wetting of powder starch with ethanol followed by dissolution with sodium hydroxide. Since the solvent system is aqueous, cooked starch samples are analysed by direct dissolution with sodium hydroxide. The method shows promise as a rapid technique in elucidating starch structure.  相似文献   
63.
The mechanical properties of plastics and elastomers reinforced by short fibers are generally dictated by the selection of matrix and reinforcement. However, the high tensile properties attainable in these systems through laboratory processing techniques are frequently not obtained in conventional fabrication operations. To gain a wider latitude in meeting economic and performance constraints, the control of composite structure in the fabrication step should not be overlooked. Tool geometry and processing conditions can be manipulated specifically to control the fiber orientation distribution in the product. A study of fiber orientation in composite compounds during flow through runners, gates, and dies leads to recommendations for optimizing the directional strength and stiffness according to a kinematic model. Performance data on parts fabricated from various short-fiber composite materials bear out these projections.  相似文献   
64.
Short fibers of natural cellulose treated to provide dispersability and strong interfacial bonding are ideal reinforcements for plasticized vinyl compounds. The development of substantial strength and stiffness in unidirectional composites indicates the reinforcing potential of these high aspect-ratio fibers in soft compositions. Special extrusion dies developed to control fiber directionality in rubber extrudates are equally applicable to vinyl hose. The unusual expanding geometry of these tools aligns the fibers toward the circumferential direction to provide optimum reinforcement against contained pressure loading. Thus, reinforced poly(vinyl chloride) air and water hoses can be produced in a single extrusion step, since all of the necessary reinforcement is contained in the compound.  相似文献   
65.
The objective of this article is to synthesize research findings and requirements pertaining to development of time-sensitive remote-sensing systems (TSRSS) that support decision-making pertaining to post-hazard assessment of damage to what we define as hyper-critical infrastructure (HCI), based on an aerial imaging approach known as repeat station imaging (RSI). The following TSRSS components are addressed and related findings are reported: (1) understanding information requirements of emergency managers pertaining to damage of HCI; (2) flight planning and data capture requirements for supporting bi-temporal RSI pairs; (3) automatic image registration and shadow classification and normalization routines applied to RSI pairs; (4) damage detection and delineation approach that exploits simple temporal differences in image brightness to automatically, reliably, and robustly delineates new cracks associated with damage; and (5) rapid data and information transfer to emergency managers. The highest priority follow-on research topics are: (1) integrating small unmanned aerial systems (sUAS) with the RSI approach, while enabling multiple view perspectives other than vertical (i.e. nadir pointing) and (2) developing and testing of machine learning routines for automatic identification of damage features from RSI pairs, particularly those captured from integrated sUAS–RSI.  相似文献   
66.
We have analyzed the T-cell receptor (TCR) V beta repertoire using polymerase chain reaction (PCR) in a cohort of eight patients receiving allogeneic bone marrow transplantation (BMT) from related and unrelated donors at the City of Hope. Results of PCR studies from graft-versus-host disease (GVHD) skin lesions show a bias in the usage of TCR V beta families, whereas examination of peripheral blood (PB) withdrawn at the same time did not reveal a similar phenomenon. In one such family, TCR V beta 2 is predominantly expressed in 7 of 7 biopsy specimens examined. V beta 2 TCR expression from these patients was analyzed more extensively using a combination of individual TCR gene cloning, followed by sequence analysis. We found evidence of oligoclonal expansion of single V beta 2-bearing TCRs in GVHD lesions, and in the PB of some patients after diagnosis of GVHD. In contrast, GVHD-negative biopsy samples showed no evidence for clonotypic TCR amplification. Sequence-specific TCR CDR3 region probes were derived from analysis of the predominant expressed TCR in GVHD lesions, and used to probe Southern blots of amplified V beta 2 TCR mRNA from PB and tissue from BMT recipients and their respective donors. In most cases the probes are highly specific in detecting TCR expression from GVHD lesions alone, although in several instances expression could be detected in PB after GVHD diagnosis. These data provide supporting evidence for the hypothesis that acute GVHD is associated with expansion of T-cell clones expressing antigen-specific TCRs that may contribute to the disease pathology.  相似文献   
67.
68.
L1, NCAM and N-cadherin are cell adhesion molecules (CAMs), present on neuronal growth cones, which promote cell-contact dependent axonal growth by activating a second messenger pathway in neurons that requires calcium influx through L- and N-type calcium channels. In the present study we show that two of these CAMs, (L1 and N-cadherin) can stimulate neurite regeneration from axotomised adult dorsal root ganglion (DRG) neurons cultured in vitro and that this response can be fully inhibited by agents that block or negate the effect of calcium influx into the neurons. However although the response required calcium influx into neurons, it was not associated with an increase in the steady state levels of calcium in neuronal growth cones. These results suggest that small localised changes, or increases in the rate of calcium cycling, in growth cones and/or filopodia, are more important for regulating axonal growth than changes in the steady-state level of calcium.  相似文献   
69.
Prothrombin and thrombin are involved in diverse biological functions. The structure of prothrombin has been studied extensively and its cDNA has been cloned from several species. The tissue-specific expression of this protein has been studied, as well as the developmental expression pattern. The structure of the human gene coding for prothrombin has been determined, and gene regulation studies have been performed that indicate that HNF-1 might be responsible for the liver-specific expression of this protein. Other regulatory elements have been identified. In order to further study the biological properties of prothrombin, prothrombin-deficient mice have been generated using gene targeting technology. Prothrombin deficiency in mice results in partial embryonic lethality. The mice that survive to birth die from bleeding events. The embryonic lethality occurs between embryonic days 9.5 and 11.5 and appears to be due to the loss of integrity of the vasculature due to a failure in blood coagulation. These results indicate that prothrombin plays not only a key role in hemostasis but suggests that it may be important for mouse development.  相似文献   
70.
We proposed the endogenous thrombin potential (ETP) as an overall function test of the coagulation system. We recently introduced a routine test which requires defibrinated plasma. In order to develop an assay in which the ETP-value can be directly obtained by measuring the optical density, we investigated two methods to inhibit fibrinogen clottability and to inactivate alpha2-macroglobulin. The first method makes use of hydroxylamine to inactivate alpha2-macroglobulin and H-Gly-Pro-Arg-Pro-OH to inhibit fibrin polymerization. At pH 7.35, plasma incubated with 25 mM hydroxylamine and 1.5 mg/mL H-Gly-Pro-Arg-Pro-OH for 5 minutes at 37 degrees C resulted in a reduced endlevel of the amidolytic activity on small chromogenic substrates. The second method uses a metalloprotease purified from Crotalus basiliscus to remove alpha2-macroglobulin from plasma in combination with H-Gly-Pro-Arg-Pro-OH. Herein plasma is incubated with 3.5 LM protease during 15 minutes at 37 degrees C in the presence of 1 mg/mL polymerization inhibitor. The enzymatic method results in a zero endlevel of the amidolytic activity and this would imply that measurement of the ETP is reduced to an endpoint determination of the optical density. We show that the endpoint determination of the optical density correlates well with the calculated ETP in plasmas with different degrees of anticoagulation.  相似文献   
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