Smoking behavior during the first 24 hours of a quit attempt is a significant predictor of longer-term abstinence, yet little is known about the neurobiology of early tobacco abstinence. ...Specifically, the effects of acute tobacco deprivation and reinstatement on brain function—particularly at the level of large-scale network dynamics and assessed across the entire brain—remain incompletely understood. To address this gap, this study used a mixed within- and between-subjects design to assess the effects of smoking status (yes/no smoker) and state (deprived vs. satiated) on whole-brain patterns of intrinsic connectivity.
Participants included 42 tobacco smokers who underwent resting-state functional magnetic resonance imaging following overnight abstinence (deprived state) and following smoking reinstatement (satiated state, randomized order across participants). Sixty healthy control nonsmokers underwent a single resting-state scan using the same acquisition parameters. Functional connectivity data were analyzed using both a canonical network-of-interest approach and a whole-brain, data-driven approach, i.e., intrinsic connectivity distribution.
Network-of-interest–based analyses indicated decreased functional connectivity within frontoparietal and salience networks among smokers relative to nonsmokers as well as effects of smoking state on default mode connectivity. In addition, intrinsic connectivity distribution analyses identified novel between-group differences in subcortical-cerebellar and corticocerebellar networks that were largely smoking state dependent.
These data demonstrate the importance of considering smoking state and the utility of using both theory- and data-driven analysis approaches. These data provide much-needed insight into the functional neurobiology of early abstinence, which may be used in the development of novel treatments.
Tri-
n-butyltin (TBT), a biocide, is known for its immunotoxicity and hepatotoxicity and is a well-characterised mitochondrial toxin. This report investigates the mechanisms involved in induction of ...apoptosis by TBT in primary cultures of rat hepatocytes. Release of cytochrome
c from mitochondria into the cytosol was apparent after 15 min of exposure to 2.5 μM TBT. In addition, activity of initiator caspase-9 increased after 30 min, representing activation of the mitochondrial pathway in hepatocytes. The death receptor pathway was also activated by TBT, as indicated by recruitment of the adaptor protein FADD from the cytosol to the membrane as soon as 15 min after treatment. In addition, levels of the pro-apoptotic protein Bid decreased in the cytosol, while there was an increase in levels of the cleaved form tBid, in TBT-treated hepatocytes. Activity of initiator caspase-8 increased after 30 min. The principal effector caspase-3 was activated following 30 min of treatment with TBT. Activation was confirmed by immunodetection of a 17-kDa cleaved fragment. Apoptotic substrates such as Poly(ADP-ribose) polymerase and DNA fragmentation factor-45 are cleaved by caspase-3 to ensure the dismantlement of the cell. Cleavage of Poly(ADP-ribose) polymerase into a 85-kDa fragment appeared after 30 min of TBT treatment. DNA fragmentation factor-45 disappeared in TBT-exposed rat hepatocytes. This is the first detailed study reporting the involvement of initiator and effector caspases, cleavage of their intracellular substrates and activation of both death receptor and mitochondrial pathways in TBT-induced apoptosis in rat hepatocytes. The comprehension of molecular events of apoptosis is important for the evaluation of the risk to humans and animals.
Suitable execution of moderation policy is challenging but crucial for the trustworthiness and credibility of internal high-stakes assessment systems. In formal education, policies are rarely ...implemented as intended. Instead, they are
enacted
in ways influenced by mediating factors including the internal and external contexts of organisations. Ball, Maguire and Braun’s (2012) contextual-dimensions heuristic provides a conceptualisation of organisation-specific contexts, which is useful when the organisation is the unit of analysis. However, comprehensive analysis of policy enactment—including that relating to moderation—warrants consideration of contexts narrower in scope than whole organisations
and
wider in scope than individual organisations. In this article, we modify Ball and colleagues’ heuristic, incorporating Biggs’ (1993) application of systems theory, to develop a new contextual framework for moderation that is applicable on multiple scales and enables such analysis. This framework is applied to a selection of contemporary moderation studies with scopes that vary from one course, to jurisdiction-wide, to illustrate its utility. Our framework captures the hierarchy of embedded, interacting systems within which moderation is enacted and makes contextual relationships visible, allowing consideration of perspectives between units of analysis. Our framework provides a nuanced conceptualisation of context that distinguishes between
material
and
human
factors, and
intrinsic
and
extrinsic
contexts. We present potential uses of the framework for education organisations, central agencies and researchers including as a tool for identifying contextual factors involved in executing moderation initiatives and identifying possible pressures, tensions and enablers.
The ignition of flammable atmospheres from hot surfaces arising from mechanical interactions has been a significant cause of many industrial and mining explosions. An investigation of the surface ...temperature generation resulting from sliding friction during short duration mechanical impacts has been carried out and the nature and usefulness of dynamic thermocouple measurement examined in the context of predicting mechanical ignition. The experimental results reveal that there is only a limited relationship between the measured maximum temperatures and the tangential energy loss during an impact. This appears to be mostly due to variation of the extent to which the tangential energy loss represents frictional loss (associated with tip sliding) rather than material deformation. Whilst an increase in impact energy tends to raise the measured surface temperature, there is significant random variation under nominally similar conditions. It is considered that this is associated with the randomness and changing nature of the contacting areas. During the small time-period of a mechanical impact, there is insufficient time for any equalisation of temperature between neighbouring contact zones to take place. With reference to the ignition of flammable gases brought about by mechanical impact, surface temperatures measured by dynamic thermocouple appear to offer only limited predictive usefulness since they could be associated with contact areas of insufficient size to transfer enough energy into the gas mixture to cause ignition. Finger-marking impact surfaces has the effect of greatly reducing the frictional energy loss but this is not fully reflected in the measured maximum surface temperature. It is concluded that ignition prediction should still be based on tests conducted with mechanical impacts taking place in an ambient flammable atmosphere.
•We consider ignition of flammable atmospheres from hot impact surfaces.•Generated contact temperatures are measured during mechanical impact.•We relate surface temperatures to experimentally found energy losses.•Considerable variation of impact nature occurs under same nominal conditions.•Dynamic thermocouple offers limited usefulness for impact ignition prediction.
Treatment data from a university counseling center (UCC) that utilized the Outcome Questionnaire-45.2 (OQ-45;
M. J. Lambert et al., 2004
), a self-report general clinical symptom measure, was ...compared against treatment efficacy benchmarks from clinical trials of adult major depression that utilized similar measures. Statistical analyses suggested that the treatment effect size estimate obtained at this counseling center with clients whose level of psychological distress was above the OQ-45 clinical cutoff score was similar to treatment efficacy observed in clinical trials. Analyses on OQ-45 items suggested that clients elevated on 3 items indicating problematic substance use resulted in poorer treatment outcomes. In addition, clients who reported their relational status as separated or divorced had poorer outcomes than did those who reported being partnered or married, and clients reporting intimacy issues resulted in greater numbers of sessions. Although differential treatment effect due to training level was found where interns and other trainees had better pre-post outcome than did staff, interpretation of this result requires great caution because clients perceived to have complicated issues are actively reassigned to staff. More effectiveness investigations at UCCs are warranted.
It is hypothesized that decreasing mean annual temperature and rates of nitrogen (N) cycling causes plants to switch from inorganic to organic forms of N as the primary mode of N nutrition. To test ...this hypothesis, we conducted field experiments and collected natural-abundance δ^sup 15^N signatures of foliage, soils, and ectomycorrhizal sporocarps along a steep elevation-climate gradient in the White Mountains, New Hampshire, USA. Here we show that with increasing elevation organic forms of N became the dominant source of N taken up by hardwood and coniferous tree species based on dual-labeled glycine uptake analysis, an important confirmation of an emerging theory for the biogeochemistry of the N cycle. Variation in natural abundance foliar δ^sup 15^N with elevation was also consistent with increasing organic N uptake, though a simple, mass balance model demonstrated that the uptake of δ^sup 15^N depleted inorganic N, rather than fractionation upon transfer of N from mycorrhizal fungi, best explains variations in foliar δ^sup 15^N with elevation. PUBLICATION ABSTRACT
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