3,648 research outputs found
Missouri Firefighter\u27s Rule, The
The firefighter\u27s rule bars injured firefighters and police officers from recovering against individuals whose ordinary negligence created the situation that required the presence of the officer or firefighter. In Missouri, the firefighter\u27s rule originated as a landowner liability rule and as an exception to the rescue doctrine More recently, however, the rule has been influenced by the doctrine of assumption of risk and by public policy concerns. The result has been a hodgepodge of old and new rationales that form the basis for an inconsistent rule that relies on superfluous analysis. In Gray v. Russell, the Missouri Supreme Court reasserted the firefighter\u27s rule\u27s basis in the rescue doctrine, and thereby prevented a beneficial change in analysis
The investigation of innate immune system memory in rag1-/- mutant zebrafish
The innate immune system in vertebrates is considered to lack specific memory. To investigate innate immune system based immunological protection mediated by cells that are not part of the acquired immune system the Tübingen recombination activation gene1 (rag1)t26683 mutant (MT) zebrafish was chosen. Molecular analysis demonstrated MT zebrafish kidney cells expressed Non-specific Cytotoxic cell receptor protein-1 (NCCRP-1) and Natural Killer cell (NK) lysin but lacked T cell receptor (TCR) and immunoglobulin (Ig) VH1, VH2, VH3 and VH4 expression. Differential counts of peripheral blood leukocytes indicated that MT fish had decreased lymphocyte populations (34.7%) compared to rag1+/+ wild-type (WT) fish (70.5%), and increased granulocyte populations (34.7%) compared to WT (17.6%). Further, endocytic functions of phagocytes from MT fish were compared to WT fish. No significant differences in the selective and non-selective mechanisms of uptake in phagocytes were observed between MT and WT zebrafish. For the first time it was shown that zebrafish phagocytes utilize macropinocytosis and Ca2+ dependant endocytosis mechanisms for antigen uptake. These characterization studies suggest that MT zebrafish provide a unique model for investigating innate immune responses because fully functional innate defenses are present without the influence of lymphocytes and lymphocyte associated acquired immune responses. To conduct such large scale investigations the first ongoing rag1t26683 mutant zebrafish breeding colony was established. To meet special husbandry needs of immunodeficient MT zebrafish, standard rearing protocols were advanced and the information was made available to the zebrafish community at: http://www.cvm.msstate.edu/zebrafish/index.html. Multiple trials were conducted to evaluate the potential for memory of the innate immune system. Significant reduction in mortality was observed in MT vaccinated zebrafish upon secondary exposure to Edwardsiella ictaluri when compared to unvaccinated, MT fish. This documents for the first time, that MT zebrafish, lacking an acquired immune system, are able to mount a protective immune response to Edwardsiella ictaluri and generate protection upon a repeated encounter to the same pathogen. The observed protection is long lasting and mediated by the innate immune system, but a specific mechanism is not yet defined
Protected species aerial survey data collection and analysis in waters underlying the R-5306A airspace: final report submitted to US Marine Corps, MCAS Cherry Point
To be in compliance with the Endangered Species Act and the Marine Mammal Protection Act, the United States Department of the Navy is required to assess the potential environmental impacts of conducting at-sea training operations on sea turtles and marine mammals. Limited recent and area-specific density data of sea turtles and dolphins exist for many of the Navy’s operations areas (OPAREAs), including the Marine Corps Air Station (MCAS) Cherry Point OPAREA, which encompasses portions of Core and Pamlico Sounds, North Carolina.
Aerial surveys were conducted to document the seasonal distribution and estimated density of sea turtles and dolphins within Core Sound and portions of Pamlico Sound, and coastal waters extending one mile offshore. Sea Surface Temperature (SST) data for each survey were extracted from 1.4 km/pixel resolution Advanced Very High Resolution Radiometer remote images. A total of 92 turtles and 1,625 dolphins were sighted during 41 aerial surveys, conducted from July 2004 to April 2006.
In the spring (March – May; 7.9°C to 21.7°C mean SST), the majority of turtles sighted were along the coast, mainly from the northern Core Banks northward to Cape Hatteras. By the summer (June – Aug.; 25.2°C to 30.8°C mean SST), turtles were fairly evenly dispersed along the entire survey range of the coast and Pamlico Sound, with only a few sightings in Core Sound. In the autumn (Sept. – Nov.; 9.6°C to 29.6°C mean SST), the majority of turtles sighted were along the coast and in eastern Pamlico Sound; however, fewer turtles were observed along the coast than in the summer. No turtles were seen during the winter surveys (Dec. – Feb.; 7.6°C to 11.2°C mean SST). The estimated mean surface density of turtles was highest along the coast in
the summer of 2005 (0.615 turtles/km², SE = 0.220). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2005 (0.016 turtles/km², SE = 0.009). The mean seasonal abundance estimates were always highest in the coastal region, except in the winter when turtles were not sighted in either region. For Pamlico Sound, surface densities were always greater in the eastern than western section. The range of mean temperatures at which turtles were sighted was 9.68°C to 30.82°C. The majority of turtles sighted were within water ≥ 11°C.
Dolphins were observed within estuarine waters and along the coast year-round; however, there were some general seasonal movements. In particular, during the summer
sightings decreased along the coast and dolphins were distributed throughout Core and Pamlico Sounds, while in the winter the majority of dolphins were located along the coast and in southeastern Pamlico Sound. Although relative numbers changed seasonally between these areas, the estimated mean surface density of dolphins was highest along the coast in the spring of 2006 (9.564 dolphins/km², SE = 5.571). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2004 (0.192 dolphins/km², SE = 0.066). The estimated mean surface density of dolphins was lowest along the coast in the summer of 2004 (0.461 dolphins/km², SE = 0.294). The estimated mean surface density of dolphins was lowest in Core and Pamlico Sounds in the summer of 2005 (0.024 dolphins/km², SE = 0.011). In Pamlico Sound, estimated surface densities were greater in the eastern section except in the autumn. Dolphins were sighted throughout the entire range of mean SST (7.60°C to 30.82°C), with a tendency towards fewer dolphins sighted as water temperatures increased.
Based on the findings of this study, sea turtles are most likely to be encountered within the OPAREAs when SST is ≥ 11°C. Since sea turtle distributions are generally limited by water temperature, knowing the SST of a given area is a useful predictor of sea turtle presence. Since dolphins were observed within estuarine waters year-round and throughout the entire range of mean SST’s, they likely could be encountered in the OPAREAs any time of the year. Although our findings indicated the greatest number of dolphins to be present in the winter and the least in the summer, their movements also may be related to other factors such as the availability of prey. (PDF contains 28 pages
Cause-in-Fact in Missouri: A Return to Normalcy
In order to establish liability in most tort actions, a plaintiff must show that the defendant caused the injury or harm in question. This Note focuses on the cause-in-fact requirement discussed in the Missouri Supreme Court case, Callahan v. Cardinal Glennon Hospital. In Callahan , the court dispelled much of the confusion that has plagued Missouri cause-in-fact analysis.\u27 The court clearly expounded the test for cause-in-fact questions. Furthermore, the court explained the exception to the basic test, and clarified Missouri law regarding this essential element of tort liability
Kinetic studies of the metathesis of 1-hexene using Re2O7/γ-Al2O3 and the synthesis and metathesis of oxazolines
The kinetics of the metathesis of 1-hexene using Re2O7/-Al_2O_3 as the catalyst were investigated under a variety of conditions. The experiments were carried out under high vacuum conditions. The product solutions were characterised by gas liquid chromatography and mass spectroscopy. The initial kinetics of the metathesis of 1-hexene showed that the reaction was first order in the weight of the catalyst and second order in the concentration of 1-hexene. A kinetic scheme which correlated the experimental data with the metallocarbene chain mechanism postulated by Herisson and Chauvin and the kinetics of the reaction was explained using a model based on the Langmuir-Hinshelwood theory. The low conversion of 1-hexene to its products is due to termination reactions which most likely occur by the decomposition of the metallocyclobutane intermediate to produce a cyclopropane derivative and an inactive centre. The optimum temperature for the metathesis of 1-hexene over Re_2O_7/-Al2O3 is 45oC and above this temperature, the rate of metathesis decreases rapidly. Co-catalysts alter the active sites for metathesis so that the catalyst is more selective to the metathesis of 1-hexene. However, the regeneration of metathesis activity is much worse for promoted catalysts than for the unpromoted. The synthesis and metathesis of 4,4-dimethyl-2-allowbreak (9-decenyl)-1,3-oxazoline and 4,4-dimethyl-2-allowbreak (3-pentenyl)-1,3-oxazoline was attempted and the products were analysed by thin layer chromatography, infra-red, 13C and 1H nmr and mass spectroscopy. Obtaining the oxazolines in a good yield with high purity was difficult and consequently metathesis of the impure products did not occur
Annual and Season Weight Changes in a Thirteen-Lined Ground Squirrel Population, Itasca State Park, Minnesota
The ecology of the thirteen-lined ground squirrel (Citellus tridecemlineotus) has been under investigation since 1954 on the grounds of the University of Minnesota Forestry and Biological Station located in Itasca State Park, Minnesota. Over the 11-year period, data have been collected on individuals of this small, relatively isolated, population. Studies of population dynamics, movements, activity patterns, and weights have been stressed, chiefly during the three summer months of June, July, and August. In 1964, the senior author carried out field work for the entire season from April 30 to September 14
Temporal–spectral signaling of sensory information and expectations in the cerebral processing of pain
The perception of pain is shaped by somatosensory information about threat. However, pain is also influenced by an individual's expectations. Such expectations can result in clinically relevant modulations and abnormalities of pain. In the brain, sensory information, expectations (predictions), and discrepancies thereof (prediction errors) are signaled by an extended network of brain areas which generate evoked potentials and oscillatory responses at different latencies and frequencies. However, a comprehensive picture of how evoked and oscillatory brain responses signal sensory information, predictions, and prediction errors in the processing of pain is lacking so far. Here, we therefore applied brief painful stimuli to 48 healthy human participants and independently modulated sensory information (stimulus intensity) and expectations of pain intensity while measuring brain activity using electroencephalography (EEG). Pain ratings confirmed that pain intensity was shaped by both sensory information and expectations. In contrast, Bayesian analyses revealed that stimulus-induced EEG responses at different latencies (the N1, N2, and P2 components) and frequencies (alpha, beta, and gamma oscillations) were shaped by sensory information but not by expectations. Expectations, however, shaped alpha and beta oscillations before the painful stimuli. These findings indicate that commonly analyzed EEG responses to painful stimuli are more involved in signaling sensory information than in signaling expectations or mismatches of sensory information and expectations. Moreover, they indicate that the effects of expectations on pain are served by brain mechanisms which differ from those conveying effects of sensory information on pain
Occult axillary node metastases in breast cancer: their detection and prognostic significance.
Although the presence of axillary node metastases in breast cancer is a key prognostic indicator and may influence treatment decisions, a significant proportion of patients diagnosed as axillary node negative (ANN) using standard histopathological techniques may have occult nodal metastases (OMs). A combination of limited step-sectioning (4 x 100 microns intervals) and immunohistochemical staining (with cytokeratin (MNF.116) and MUC1 (BC2) antibodies) was used to detect OM in a retrospective series of 208 ANN patients. OMs were found in 53 patients (25%), and both step-sectioning and immunohistochemical detection significantly improved detection (P < 0.05). Detection using BC2 (25%) was superior to MNF.116 (18%) and haematoxylin and eosin (H&E) (8%). OMs were found in 51 patients using only the first and deepest sectioning levels and BC2 staining. OMs were more frequently found in lobular (38%) than ductal carcinoma (25%), and more frequently in women less than 50 years (41%) than in older women (19%). Univariate overall and disease-free survival analyses showed that the presence, size and number of OM had prognostic significance as did tumour size (disease-free only) and histological and nuclear grade (P > 0.05). Cox multivariate proportional hazard regression analyses showed that the presence and increasing size of OMs were significantly associated with poorer disease-free survival, independently of other prognostic factors (P < 0.05). However there was not a significant independent association of the presence of occult metastases with overall survival (P = 0.11). These findings have important implications with regard to selection of ANN patients for adjuvant therapy
From one amino acid to another: tRNA-dependent amino acid biosynthesis
Aminoacyl-tRNAs (aa-tRNAs) are the essential substrates for translation. Most aa-tRNAs are formed by direct aminoacylation of tRNA catalyzed by aminoacyl-tRNA synthetases. However, a smaller number of aa-tRNAs (Asn-tRNA, Gln-tRNA, Cys-tRNA and Sec-tRNA) are made by synthesizing the amino acid on the tRNA by first attaching a non-cognate amino acid to the tRNA, which is then converted to the cognate one catalyzed by tRNA-dependent modifying enzymes. Asn-tRNA or Gln-tRNA formation in most prokaryotes requires amidation of Asp-tRNA or Glu-tRNA by amidotransferases that couple an amidase or an asparaginase to liberate ammonia with a tRNA-dependent kinase. Both archaeal and eukaryotic Sec-tRNA biosynthesis and Cys-tRNA synthesis in methanogens require O-phosophoseryl-tRNA formation. For tRNA-dependent Cys biosynthesis, O-phosphoseryl-tRNA synthetase directly attaches the amino acid to the tRNA which is then converted to Cys by Sep-tRNA: Cys-tRNA synthase. In Sec-tRNA synthesis, O-phosphoseryl-tRNA kinase phosphorylates Ser-tRNA to form the intermediate which is then modified to Sec-tRNA by Sep-tRNA:Sec-tRNA synthase. Complex formation between enzymes in the same pathway may protect the fidelity of protein synthesis. How these tRNA-dependent amino acid biosynthetic routes are integrated into overall metabolism may explain why they are still retained in so many organisms
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