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Graphene oxide (GO) was synthesised via the oxidation of graphite and was characterised using ATR FTIR, PXRD, SEM, TEM and TGA. These techniques confirmed the presence of characteristic oxygen-containing functional groups and the resulting increase in interlayer spacing in the nanostructure. GO is used as the support to form nanocomposites composed of combinations of the following: iron oxide nanoparticles (Fe3O4), carbon nanotubes (CNT) and palladium nanoparticles (Pd). The four final nanocomposites formed are: Pd/GO, Pd/Fe3O4/GO, Pd/CNT/GO, and Pd/CNT/Fe3O4/GO. Key intermediates were analysed using ATR FTIR for the confirmation of the modification. Additionally, all composites and their precursors underwent electron microscopic analysis to visually assess composite morphologies and the size distribution of deposited nanoparticles. The Fe3O4 and Pd nanoparticles were indistinguishable from each other in their spherical shape and particle diameters, which were no bigger than 32 nm. From the TGA, incorporation of Fe3O4, CNT and finally Pd into the nanocomposites increased total thermal stability in terms of mass percentage lost over the temperature programme. GO showed significant decomposition, with all nanocomposites remaining relatively stable up to 120 °C. ICP OES results showed total Pd content by mass percentage for each final composite, varied from 7.9% to 9.1% mass Pd/collective mass. XPS confirmed the expected elemental compositions of composites according to their structures and the Pd0 : PdII ratios are obtained. The nanocomposites were tested for the catalytic reduction of nitrophenols. Pd/CNT/Fe3O4/GO gave the highest TOF' for the reduction of 4-NP and 2-NP. For the reduction of 3-NP, Pd/GO showed the highest TOF'. Nitrophenol's pK a and catalyst TOF' correlated in a direct proportional relationship for Pd/GO and Pd/Fe3O4/GO. It was found that Pd0 surpassed PdII in catalytic activity. Reduction of PdII to Pd0 took place during the first catalytic cycle.

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Community-based dental education supports the General Dental Council learning outcomes by enabling integrated clinical practice in a primary care setting. There is little available research to identify any additional demands on the outreach clinical teacher. A case study using mixed methods, including interviews, was used to identify the supposed skills and attributes required and the individuals' perception of their preparedness for their teaching role. An online questionnaire survey of student and staff groups (N = 474) was analysed and the results informed a topic guide used in semi-structured interviews of outreach clinical teachers (N = 8). The in-depth interviews were transcribed and analysed thematically. The most desirable skills and attributes of best clinical teachers were perceived to be clinical competence, being current and able to provide clinical demonstration of procedures and to serve as a positive role model. In addition, attributes of being very experienced clinicians and providers of a safe learning environment were expressed as being particularly important to the outreach clinicians, of whom the majority felt somewhat isolated and ill-prepared for their teaching role. Outreach clinicians perceive benefit from integration with the main dental hospital site and of specific induction to their teaching role.

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OBJECTIVES: The aim of this study was to determine any increase in the incidence of cone cut errors that adversely affected diagnostic yield resulting in more retakes using rectangular collimation with film holders in bitewing radiography. Comparisons were also made with other positioning errors that occurred when bitewings were taken with circular collimation, with and without film holders. METHODS: A preliminary questionnaire was used to determine the year that rectangular collimation was adopted by military dental practice. 3 time-framed subsets, each of 1000 bitewing radiographs, were identified: subset 1, films taken with circular collimators without film holders; subset 2, films taken with circular collimators with film holders; and subset 3, films taken with rectangular collimators with film holders. Each subset was assessed for positioning errors of cone cut, horizontal overlap, vertical distortion and film centring. The χ(2) test was used to test significant differences amongst the three subsets. RESULTS: The use of film holders with circular collimation significantly reduced the incidence of cone cut errors from 21.7% to 3.3%. There was an increase in the incidence of cone cut errors from 3.3% to 20.9% when rectangular collimation was used, but the actual number considered "rejects" was very small, only 0.1% (1 in 1000 films) in subset 2 and 0.3% (3 of 1000 films) in subset 3, when assessed for diagnostic yield. CONCLUSIONS: This study provides evidence that rectangular collimation did not significantly affect the diagnostic yield of bitewing radiographs despite the presence of cone cut. Therefore, all practitioners should adopt rectangular collimation.

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Previous studies have shown that high-resolution, empirical food webs possess a non-random network structure, typically characterized by uniform or exponential degree distributions. However, the empirical food webs that have been investigated for their structural properties represent local communities that are only a subset of a larger pool of regionally coexisting species. Here, we use a simple model to investigate the effects of regional food web structure on local food webs that are assembled by two simple processes: random immigration of species from a source web (regional food web), and random extinction of species within the local web. The model shows that local webs with non-random degree distributions can arise from randomly structured source webs. A comparison of local webs assembled from randomly structured source webs with local webs assembled from source webs generated by the niche model shows that the former have higher species richness at equilibrium, but have a nonlinear response to changing extinction rates. These results imply that the network structure of regional food webs can play a significant role in the assembly and dynamics of local webs in natural ecosystems. With natural landscapes becoming increasingly fragmented, understanding such structure may be a necessary key to understanding the maintenance and stability of local species diversity.

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Data collected during the routine assessment of 117 dysphagic children with cerebral palsy have been related to both suckle feeding histories and gestational ages and to the classification of cerebral palsy. In addition, a concurrent survey involving 281 children with cerebral palsy in special schools was undertaken which revealed that the sample of referred children appeared to be a true representation of a wider population of dysphagic children with cerebral palsy. A Feeding Difficulty Symptom Score (FDSS) describes the severity of swallowing symptoms reported. A numerical Dysphagia Complexity Index (DCI) quantifies numerically the neurological complexity of the swallowing difficulty. The FDSS correlates closely with the DCI. Twenty-seven percent of mothers of the children who were referred for advice on their present swallowing difficulties stated that they recalled no suckle feeding problems. However, there was no difference in the severity of present swallowing difficulties between those infants who suckle fed well and those who experienced severe difficulties. Those referred children with cerebral palsy born at term exhibited more complex later swallowing problems and were more likely to be classified as athetoid than those born preterm.

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A variety of environmental stresses stimulate the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEKK) > stress-activated protein kinase (SAPK)-ERK kinase (SEK) > SAPK/c-Jun NH(2)-terminal kinase (JNK) stress-activated protein kinase cascade and coordinately activate the transcription factor NFkappaB. Mechanisms of stress activation upstream of MEKK1 have not been precisely determined. Redox mechanisms involving sulfhydryls are likely because N-acetyl-cysteine at millimolar concentrations blocks stress signals. Because intracellular sulfhydryl concentrations can be regulated through redox cycling involving reactive quinones (1), we tested the ability of quinone reductase inhibitors to alter stress signaling. Several quinone reductases are inhibited by dicoumarol, a coumarin derivative. Dicoumarol prevented SAPK activation in vivo by chemical cell stressors and also prevented SAPK activation induced by expression of the tumor necrosis factor alpha (TNFalpha) receptor-associated protein TRAF2 but not by expression of truncated active MEKK1. Other coumarin derivatives failed to block SAPK activation, but other inhibitors of quinone reductases, particularly menadione, similarly blocked SAPK activation. Cells deficient in a major quinone reductase, NQO1, displayed hypersensitivity to dicoumarol stress inhibition, whereas SAPK in cells reconstituted with the NQO1 gene displayed relative dicoumarol resistance. Consistent with the proposed role of overlapping upstream signaling cascades in activation of NFkappaB, dicoumarol also blocked NFkappaB activation in primary macrophages stimulated with either lipopolysaccharide or TNFalpha. In addition, dicoumarol strongly potentiated TNFalpha-induced apoptosis in HeLa cells, probably by blocking the anti-apoptotic effect of NFkappaB. The ability of dicoumarol to simultaneously inhibit SAPK and NFkappaB activation and to potentiate apoptotic cell death suggests that SAPK is not an obligate participant in apoptosis. Dicoumarol, currently in clinical use as an oral anticoagulant, represents a potential therapeutic inhibitor of the SAPK and NFkappaB response.

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While studying the stress regulation of p70/85 S6 kinase (S6K), we observed that anisomycin and UV light stimulated S6K activity, but that sorbitol inactivated S6K. Pretreatment with hyperosmotic stress also prevented the activation of S6K by both 12-O-tetradecanoylphorbol-13-acetate and anisomycin. Comparison of sorbitol and rapamycin revealed that both agents inactivated S6K and caused dephosphorylation of Ser/Thr-Pro sites in the COOH terminus of S6K, including Thr(412), a residue essential to S6K regulation, as determined by phospho-specific antibodies. Rapamycin-resistant S6K truncation mutants were similarly resistant to deactivation by sorbitol. Additionally, the PHAS-1 mobility shift, which is sensitive to rapamycin, was also found to be sensitive to osmotic stress. Experiments using the p38 inhibitor SB203580 and dominant negative mutants involving both stress-activated protein kinase/c-Jun NH(2)-terminal kinase and p38 stress pathways indicated that these pathways are probably not involved in osmotic stress inhibition of S6K. Examining the potential involvement of a phosphatase, we found that sodium pyrophosphate, sodium vanadate, cyclosporin A, tautomycin, and okadaic acid had no effect on osmotic stress inhibition of S6K. However, calyculin A prevented both rapamycin- and sorbitol-mediated deactivation of S6K. Our results suggest that osmotic stress and rapamycin act through a calyculin A-sensitive phosphatase to cause dephosphorylation and deactivation of S6K.

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The stress-activated protein kinase (SAPK, alternatively JNK) is activated rapidly by cell stress stimuli such as inflammatory cytokines and oxidative stress, and more slowly by the initiation of the apoptotic cell death response by events such as ligation of the Fas protein. Mitogen-activated protein kinase/Erk kinase kinase-1 (MEKK1) is an activator of SAPK, serving as a SAPK-kinase-kinase through intermediate phosphorylation of the SAPK kinase SEK1. By sequencing proteolytic cleavage products of MEKK1, we found that the proapoptotic protease caspase 3 (CPP32) cleaves MEKK1 after residue D68 both in vivo and in vitro. Cleavage of MEKK1 after D68 is blocked by viral and chemical protease inhibitors. Cleavage of MEKK1 at D68 changes the intracellular distribution of the protein from a Triton-insoluble compartment to a Triton-soluble compartment, reflected in a redistribution from a particulate to a diffuse cytoplasmic staining seen by immunofluorescence. Activation of both SAPK and MEKK1 after Fas ligation is prevented by both viral and chemical caspase 3 inhibitors, which in contrast fail to block activation of SAPK by rapidly acting cell stresses. Stress factor-induced SAPK signaling is not dependent on caspase 3 function. We propose that two mechanisms of stress signaling through MEKK1 exist. One is rapid, independent of proteases, and occurs in the particulate Triton-insoluble compartment. The other is more slowly activated and involves liberation of particulate MEKK1 by proteolytic cleavage and activation by caspase 3.

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In conclusion, this is a study of a 52-year-old white male who had the removal of a benign appearing nasal polyp with the surprising diagnosis of extramedullary plasmacytoma. The clinical course has been completely benign since surgery for over two years. This should alert physicians to the possibility that benign appearing polyps, on rare occasion, can be malignant, and particularly those polyps occurring on the septum should be carefully investigated. It happened that this patient had a plasmacytoma, and a search for the presence of multiple myeloma is warranted.

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Eighteen children with cerebral palsy in a special school, most of whom had feeding difficulties, were studied to compare the diagnostic value of the Exeter Dysphagia Assessment Technique (EDAT) with an exhaustive clinical assessment undertaken by a multidisciplinary team experienced in the diagnosis and treatment of dysphagia of neurological origin. Four feeding skills were assessed by each method independently, viz. anticipation, intraoral sensory perception, oral-motor efficiency, and pharyngeal triggering. Comparison of the two sets of results showed agreement in at least 78% of the assessed skills. The possible reasons for the few discrepancies are discussed. The noninvasive EDAT equipment was easy to use with the children, who had a range of type and severity of cerebral palsy. The test was undertaken in their familiar surroundings and took 15 to 20 min per child. Interpretation of the results showed that EDAT provided a rapid, reliable diagnostic aid which assisted in the assessment of the degree of feeding impairment within each of the four feeding skills tested.

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The activities involved in mediating reinforcement for a speaker's behavior constitute only one phase of a listener's reaction to verbal stimulation. Other phases include listening and understanding what a speaker has said. It is argued that the relative subtlety of these activities is reason for their careful scrutiny, not their complete neglect. Listening is conceptualized as a functional relation obtaining between the responding of an organism and the stimulating of an object. A current instance of listening is regarded as a point in the evolution of similar instances, whereby one's history of perceptual activity may be regarded as existing in one's current interbehavior. Understanding reactions are similarly analyzed; however, they are considerably more complex than listening reactions due to the preponderance of implicit responding involved in reactions of this type. Implicit responding occurs by way of substitute stimulation, and an analysis of the serviceability of verbal stimuli in this regard is made. Understanding is conceptualized as seeing, hearing, or otherwise reacting to actual things in the presence of their "names" alone. The value of an inferential analysis of listening and understanding is also discussed, with the conclusion that unless some attempt is made to elaborate on the nature and operation of these activities, the more apparent reinforcement mediational activities of a listener are merely asserted without an explanation for their occurrence.

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The scientific status of History was compared to other sciences in the critical areas event selection, investigative operations, and theory construction. First, in terms of events studied, history is regarded as a quasi-scientific study of past events. However, viewed from the science of behavior's perspective of what historians actually do, history becomes a study of current records. As a study of currently existing records, not the non-existent past, history has potential to become a science. Second, like other scientists, historians may undertake manipulative investigations: they can locate the presence and absence of a condition in records and thereby determine its relation to other recorded phenomena. A limitation has been the lack of quantification that results from emphasis on the uniqueness of things rather than on their communality. Scientific training would facilitate viewing similar things as instances of a larger class that could be counted. Another limitation that cannot be easily overcome is the inability to produce raw data. This limitation has created problems in theoretical practices, the third area of comparison, because theoretical constructions have frequently been substituted for missing data. This problem too could be reduced through scientific training, particularly in other behavior sciences. An authentic science of history is possible.

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The DNA, RNA and protein content of the cyanobacterium Anacystis nidudlans was determined in light-limited and carbon dioxide-limited chemostat cultures over the dilution rate range, D = 0.02 h-1 to 0.19 h-1. The macromolecular contents as a percentage of the dry weight and on a per cell basis varied significantly as a function of organism growth rate and the nature of the growth conditions. For both limitations the RNA content per cell increased [20-55 fg RNA (cell)-1] with increasing dilution rate and also showed an increase as a percentage of the dry weight. The DNA content as a percentage of the dry weight showed a 2-fold decrease with incresing dilution rate over the range examined. On a per cell basis DNA reached a peak at D = 0.1 h-1 [4.5 fg DNA (cell)-1] for light-limited organisms and at D = 0.08 h-1 [8.0 fg DNA (cell)-1] for carbon dioxide-limited organisms. The qRNA increased with increasing dilution rates over the complete growth rate examined whilst qDNA reached a maximum at D = 0.09 to 0.10 h-1. The protein content as a percentage of the dry weight was greater in CO2-limited organisms than light-limited organisms but in both cultures declined as the dilution rate was increased above D = 0.10 h-1.

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