We consider critical factors such as the degree of control that an animal believes it exerts over key aspects of its environment, the distinction between ‘better’ and ‘good’ actual or predicted future states, and the potential requirement for a particular form of opponent to dopamine to ensure proper calibration of state values.We enjoy a sophisticated understanding of how animals learn to predict appetitive outcomes and direct their behaviour accordingly. This encompasses well-defined learning algorithms and details of how these might be implemented in the brain. Dopamine has played an important part in this unfolding story, appearing to embody a learning signal for predicting rewards and stamping in useful actions, while also being a modulator of behavioural vigour. By contrast, although choosing correct actions and executing them vigorously in the face of adversity is at least as important, our understanding of learning and behaviour in aversive settings is less well developed. We examine aversive processing through the medium of the role of dopamine and targets such as D Our comprehension of appetitive Pavlovian and instrumental conditioning at multiple levels of theory and experiment has progressed dramatically over the last few years. We now enjoy a richly detailed picture, encompassing computational questions about the sorts of prediction and optimization that animals perform, and priors over these; algorithmic issues about the nature of different sorts of learning that get recruited and exploited in various circumstances; and implementational details about the involvement of many structures, including substantial pre-frontal cortical areas, the amygdala, the striatum, and also their respective dopaminergic neuromodulation –8. AlongBy contrast, the case of aversive Pavlovian and instrumental conditioning is rather less well understood. Perhaps the most venerable puzzle concerns the instrumental case of active avoidance: how could it be that the desired absence of an aversive outcome can influence the choice and motivation of behaviour –22? Howe2 receptors because of their seemingly special role in passive forms of behavioural inhibition [In this review, we examine aversion through the medium of dopamine and some of its key targets. Dopamine is by no means the only, or perhaps even the most important, implementational facet of negative valence. For instance, as we will see, complex, species-specific, defensive systems provide an elaborate hard-wired mosaic of responsivity to a panoply of threatening cues –29. Furthibition , 33.Almost all the elements of this account have been aired in previous analyses of appetitive and aversive neural reinforcement learning, with the role of dopamine also attracting quite some attention –40. Our Reinforcement learning (RL) addresses the following stark problem: learn to choose actions which maximize the sum of a scalar utility or reward signal over the future by interacting with an initially unknown environment. Such environments comprise states or locations, and transitions between these states that may be influenced by actions. What make this problem particularly challenging are both the trial-and-error nature of learning—the effect of actions must be discovered by trying them—and the possibility that actions affect not only immediate but also delayed rewards by changing which states are occupied in the future .model-based and model-free methods [Two broad classes of RL algorithms address this computational problem:  methods , 42. Bri methods –46. Mode methods .value of a state, which summarizes how good it is as judged by the cumulative rewards that are expected to accrue in the future when the subject starts from that state. This is, of course, the quantity that requires optimization. Crucially, the values of successive states satisfy a particular consistency relationship [temporal difference (TD) methods, use inconsistencies in the values of sampled successive states—a TD prediction error signal—to improve estimates of state values [By contrast, model-free methods do not construct an internal model, but rather learn simpler quantities in the service of the same goal. One such is the mean tionship , so thate values .actor-critic [critic, which uses the TD error to learn the model-free value of each state. However, future rewards typically depend on the actions chosen, or the behavioural policy followed. A policy is a state-response mapping, and is stored in the other component, the actor, which determines the relative probabilities of selecting actions. It turns out that the same TD prediction error that can improve the predictions of the critic may also be employed to improve the choices of the actor. There are also other model-free quantities that can be used for action selection. These include the Q value [For selecting appropriate actions, a prominent model-free method is the r-critic , 49. Thi Q value  of a staSuch model-free methods have the virtue of being able to learn to choose good actions without estimating a world model. However, summarizing experience by simple state values also means that these methods are relatively inflexible in the face of changes in environmental contingencies. Consequently, model-free RL methods have been suggested as a possible model of habitual actions , 45.exploration bonus, quantifying optimism in the face of uncertainty [Both model-based and model-free methods must balance exploration and exploitation. The former is necessary to learn the possibilities associated with a novel domain; the latter then garners the rewards (or avoids the punishments) that the environment has been discovered to afford. This balance depends sensitively on many factors, including prior expectations about the opportunities and threats in the environment, how much control can be exerted over them, and how fast they change . It alsoertainty , 55.Calculating such bonuses correctly, balancing exploration and exploitation optimally, and even just finding the optimal trajectory of actions in a rich state space, are radically computational intractable; heuristics therefore abound which are differently attuned to different classes of method . Perhapsunconditioned stimuli (USs). Presentation of a US typically inspires what is known as a consummatory response, attuned to the particularities of the US. It is through Pavlovian, or classical, conditioning that such innate responses can be attached not only to USs but also to formerly neutral predictors of such outcomes. These predictors are then called conditioned stimuli (CSs) since their significance is ‘conditioned’ by experience. Along with targeted preparation for particular outcomes, CS-elicited conditioned responses (CRs) include generic, so-called preparatory, actions: typically approach and engagement for appetitive cues, associated with predictions of rewarding outcomes; and inhibition, disengagement and withdrawal for aversive cues, associated with future threats or punishments. The predictions that underpin preparation can be either model-based or model-free [Such hard-wired behaviours may be elicited in the absence of learning by certain stimuli, which are therefore designated del-free . We shoudel-free –59 is nodel-free , 60–66.The fuller case of RL, in which actions come to be chosen because of their contingent effects rather than being automatically elicited by predictions, corresponds to instrumental conditioning. At least in experimental circumstances such as negative automaintenance , automatWe start by considering the implications of Pavlovian and instrumental paradigms for the neural realization of control. We use a rather elaborated discussion of appetitive conditioning and rewards as a foundation, since this valence has received more attention and so is better understood. As a preview, we will see that dopamine in the ventral striatum has a special involvement in model-free learning (reporting the TD prediction error). However, dopamine likely also plays an important role in the expression and invigoration of both model-based and model-free behaviour.Model-free RL, with its TD prediction errors, has played a particularly central role in developing theories of how animals learn state values, the latter interpreted as the predictions of long run rewards that underpin Pavlovian responses –77. TherAlong with its involvement in plasticity, dopamine, particularly in the NAc, has long been implicated in the intensity of the expression of innate, motivated behaviours  in response to both unconditioned and conditioned stimuli , 86, 87.The influence of dopamine neurons over the expression of behaviour might extend to model-based as well as model-free predictions, based on other afferent projections to the dopamine system. Model-based values are thought to be stored in, and calculated by, other areas, such as the basolateral amygdala and orbitofrontal cortex , 102–109Three further details of the ventral striatum and dopamine release in this structure are important. Firstly, anatomically, the NAc is classically subdivided into ‘core’ (NAcC) and ‘shell’ (NAcS) subregions . As wellTwo related ideas are abroad about the separate roles of these structures. One is that NAcS and NAcC mediate the motivational impact of USs and CSs, respectively . For insoutcome-specific and general PIT, respectively [The other idea is that NAcS and NAcC are involved in ectively . The difectively .These ideas are not quite compatible, since both sorts of PIT involve conditioned stimuli. Perhaps, instead, we should think of the NAcC as being more involved in preparatory behaviours, attuned only to the valence (positive or negative) of a predicted outcome but not its particularities, while the NAcS is more involved in consummatory behaviours, which additionally reflect knowledge of the particular expected outcome(s) –123. Thi1 or D2 receptors, but not both [1-like (D1 and D5 receptors), and D2-like . D1 and D2 receptors are of prime interest here since they are by far the most abundantly expressed dopamine receptors in the striatum and throughout the rest of the brain [1 and D2 receptors are thought to occupy states in which their affinities for dopamine are low and high respectively [1 and D2 receptors appear to mediate opposite effects of dopamine on their targets: activation of D1 receptors tends to excite, and D2 to inhibit, neurons; this modulation of excitability can then also have consequences for activity-dependent plasticity [The second relevant, if somewhat contentious (see below), feature is that, as appears to be the case in the striatum generally, the majority of the principal projection neurons in NAc—medium spiny neurons (MSNs)—may express either Dnot both , 125. Brhe brain –128. In ectively , with thectively . Furtherasticity , 132.1-expressing ‘Go’  and D2-expressing ‘NoGo’  pathways [1-expressing MSNs within NAcC are reported to also project within the striatopallidal (‘indirect’) pathway [1 and D2 receptors, particularly in NAcS [1 and D2 receptors can interact to form heteromeric dopamine receptor complexes within the same cell [1 receptors may be of particular importance in learning Pavlovian contingencies [1 or D2 receptors appear to disrupt the expression of such learning [1 and D2 receptors in these respective areas in appetitive conditioning appears to be lacking.In the dorsal striatum, there is substantial evidence for an anatomical segregation between Dpathways , 133–136pathways , as we dpathways –140 althpathways , 141–143 pathway ; there i in NAcS , 146; aname cell , 148, thame cell . In funcngencies –154, whilearning –159, inclearning , 153. UnThe third detail, which applies equally to ventral and dorsal striatum, concerns the link between the activity of dopaminergic cells and the release of dopamine into target areas. While there is little doubt that phasic release of striatal dopamine can be driven by activity in midbrain dopaminergic cells (e.g. ), a rangIn the instrumental, model-free, actor-critic method, the critic is the Pavlovian predictor, associated with the ventral striatum. The actor, by contrast, has been tentatively assigned to the dorsal striatum , 80, 1691-expressing (dMSNs) and D2-expressing (iMSNs) medium spiny neurons are organised respectively into a direct  pathway, which promotes behaviour, and an indirect  pathway, which suppresses behaviour [1 and D2 receptors would then allow dopamine to modulate the balance between the two pathways by differentially regulating excitability and plasticity [1 receptors in dMSNs increases their excitability and strengthens the direct pathway via long-term potentiation (LTP) of excitatory synapses. By contrast, activation of D2 receptors in iMSNs decreases their excitability and weakens the indirect pathway by promoting long-term depression (LTD) of excitatory synapses.As noted above, the classical view of dorsal striatum is that the projections of largely separate populations of Dehaviour , 134. Thasticity . In partThis effect is then the basis of an elegant model-free account of instrumental conditioning , 180–182While it is natural to associate a dopamine TD prediction error with model-free prediction and control, there are hints that this signal shows a sophistication which potentially reveals more model-based influences , 188–191Along with Pavlovian vigour is the possibility of choosing the alacrity or force of an action based on the contingent effects of this choice. Dopamine has also been implicated in this , potentiOne idea is that there is a coupling between instrumental vigour and relatively tonic levels of dopamine, in the case that the latter report the prevailing average reward rate , 197. ThThe putative involvement of dopamine in both vigour and valence leads to the prediction of a particular sort of hard-wired misbehaviour, or Pavlovian-instrumental conflict, namely that it might be hard to learn to withhold actions in the face of stimuli that predict rewards if inhibition is successful. This is indeed true, for both animals  and humaThe main intent of this review is to understand how the elements of adaptive behaviour that we have just described apply in the aversive case. Coarsely, we need to (i) examine the complexities of consummatory versus preparatory, and active versus passive, defensive choices in the face of unconditioned aversive stimuli and their conditioned predictors; (ii) consider how instrumental avoidance actions can be learned to prevent threats from arising in the first place; and (iii) consider how the vigour of defensive actions is set appropriately.The reason that we structured this review through the medium of dopamine is that it seems that many of the same dopaminergic mechanisms that we have just described for appetitive conditioning also operate in the aversive case, subject to a few added wrinkles. This makes for puzzles, both for aversion  and for dopamine (why dopamine would apparently be released in just such purely aversive circumstances).safety , which ety  depending on how it needs to be handled. However, the response elicited by an aversive US—notably fleeing, freezing, or fighting—appears to depend in a richer way on the nature of the perceived threat, and indeed the species of the animal threatened . Differeactive defensive responses, such as fight, flight, or freeze, and passive ones, such as quiescence, immobility, or decreased responsiveness. These need to be engaged in different circumstances, subject particularly to whether or not the stressor is perceived as being escapable or controllable [engagement with the environment, while passive responses entail a degree of disengagement from the environment [For our purposes, the most important distinction is between rollable . Thus, aironment . Even fr2 receptors in this area, promotes active defence, whereas a decreased tonic level of dopamine in NAc, and the resulting decrease in D2 stimulation, promotes passive defence. This suggestion has clear parallels in the appetitive case. As there, in addition to the canonical direct and indirect pathways, typically associated with dorsal striatum and the expression of instrumental behaviours via disinhibition of cortically-specified actions [The potential link to dopamine here is the proposal, particularly advocated by Cabib and Puglisi-Allegra –211 and  actions , 212, we actions , 214.For dopamine release, studies using microdialysis to measure extracellular concentrations of dopamine have reported elevated levels in response to an aversive US in NAc , 216, asThe substrate for this release is less clear. As we noted, many dopamine neurons appear to be activated by unexpectedly appetitive events. Although most studies report that dopamine neurons are inhibited by an aversive US , there are long-standing reports suggesting that a relatively small proportion may instead be activated . The dop2 receptors in defence comes from a series of experiments exploiting the ability of local disruptions to glutamate signalling in NAcS to elicit motivated behaviours [1 and D2 receptors. By contrast, (appetitive) feeding behaviour, elicited by glutamate disruption more rostrally in the medial NAcS, only requires intact signalling of D1 receptors [1 receptors in active defence—as well as particular subregions of NAcS . Mohaviours , 229. Thhaviours  have shohaviours , but alseceptors . This reough see  for evid2 stimulation in active defence, though do not necessarily trace this to NAcS. For example, the expression of certain defensive behaviours in cats , elicitable by electrical stimulation in ventromedial hypothalamus, can also be respectively instigated or blocked by direct microinjection into that area of a D2 agonist or antagonist [Other studies also suggest a role for Dtagonist , 233. Intagonist , 214.2 stimulation. Evidence for the other side of the proposal—promotion of passive Pavlovian defences via a drop in dopamine release and reduced NAc D2 stimulation—is provided by experiments in which animals are exposed to chronic (i.e. inescapable) aversive stimuli, such as in animal models of depression [Such lines of evidence are consistent with promotion of active Pavlovian defences via enhanced dopamine release and increased NAc Dpression . Brieflypression –237, butpression –241. Sin2 stimulation in particular, and analgesia [2-expressing) iMSNs in NAc [2 receptors [Pain research provides a complementary view. Bolles and Fanselow  pointed nalgesia , 243. Cos in NAc , and thas in NAc . In turneceptors , 247. Bo2 signalling in particular, in modulating defence, we note some important caveats. As mentioned earlier, the separation of direct and indirect pathways in the accumbens is subject to continuing debate, with evidence that D1-expressing MSNs in NAc also project within the canonical indirect pathway [1 and D2 receptors [2 receptors may be more attuned to changes in tonic dopamine levels by virtue of their higher affinity, such changes presumably affect occupancy at both D1 and D2 receptors dependent on their affinities [1 and D2 systems that can be independently switched on and off, the true situation is likely to be more complex. Furthermore, experiments involving dopamine receptor agonists and antagonists can be difficult to interpret, since they may involve certain side-effects—such as the well known extrapyramidal symptoms associated with D2 antagonists [While these various lines of evidence point to involvement of accumbens dopamine, and NAc D pathway  and thateceptors . Furtherfinities . In shoragonists —and plac2 receptors raise two salient issues. The first is how to make sense of the apparent asymmetry in the involvement of D2 receptors in defensive, as opposed to appetitive, behaviours. One possibility starts from the observation that traditional paradigms assessing the interaction of Pavlovian and instrumental conditioning suggest that the Pavlovian defence system is biased towards behavioural inhibition in the face of threat [disinhibit active defensive responses when required. Of course, this mechanistic speculation merely poses the further question of why the Pavlovian defence system should be biased towards behavioural inhibition in the first place. One dubitable speculation is that this stems from asymmetries in the statistics of rewards and punishments in the environment [From an RL perspective, the roles of dopamine and Df threat , 250. Thironment . HoweverThe second, and more fundamental, issue is how to interpret variation, particularly enhancement, of NAc dopamine release in response to an aversive US in the first place, given the apparent tie between dopamine, appetitive prediction errors, and reward rates. This is the extended version of the puzzle of active avoidance to which we referred at the beginning. To answer this, we first consider certain similarities and differences between the unexpected arrival of an appetitive or aversive US . This reworse than originally expected, since the animal is now in an undesirable state of danger: i.e., (a) the aversive US is an ‘unpredicted predictor of possible future punishment’. As such, we should expect a negative prediction error. Indeed, at least the net value of the prediction error had better be negative to avoid misassignment of positive values to dangerous states and the consequent development of masochistic tendencies . On the other hand, relative to this new state of danger, the possible prospect of future safety—a positive outcome—comes into play. That is, at the point that the animal would actually manage to eliminate the threat if it can do so, the change in state from danger to safety would lead to an appetitive prediction error—just as with the change in state associated with the unexpected observation of food. Thus, provided the animal has the expectation that it will ultimately be able to achieve safety, i.e., that the situation is controllable, observation of the aversive stimulus should predict this future appetitive outcome, and so (b) lead to an immediate appetitive prediction error. The challenge therefore seems to be that of reconciling (a) and (b), i.e., the role of the aversive US as unpredicted predictor of both danger and possible future safety. To avoid any confusion, note that we discuss learning processes associated with signalling safety below; here, we consider hard-wired assessments of the absence of danger.Consider now the arrival of an unexpected aversive US (e.g. the sight of a predator). What this event signifies seems more complex. On the one hand, this surprising event presumably indicates that the present situation is opponency [One attractive reconciliation comes from appealing to the concept of pponency , 254. Hepponency , with thpponency , 256), spponency .a priori belief that safety is controllable, but the unexpected (and therefore ‘novel’) arrival of an aversive US may nevertheless be attended by uncertainty about how this new situation should be controlled. The issue of how exploration may then be carried out in a benign manner is of course particularly salient here . Of particular note is that insufficient exploration can lead to persistent miscalibration [2 receptors, leading to a lack of inhibition of passive defensive mechanisms, could readily have the same consequence.A further consideration is the value of exploration. In appetitive contexts, we noted that exploration can be motivated by bonuses associated with the future value of what might be presently discovered. A potential heuristic realization of this was through the phasic activity of dopamine neurons inspired by novel stimuli , 193. Coee, e.g. ). The idee, e.g. . In theiibration . That isibration , 32). AtRelevant to the issue of exploration and dopamine’s possible involvement is the topic of anxiety. Fear and anxiety can be differentiated both by the behaviours they characteristically involve and their sensitivity to pharmacological challenge , 260. ExIn addition to evidence that some dopamine cells show phasic excitation in response to an aversive US, we also noted evidence from microdialysis studies for enhanced dopamine release in response to an aversive US over longer periods of time. What is the aversive parallel of the suggestion in the appetitive case that tonic dopamine levels, particularly in NAc, reflect an average reward rate which realizes the opportunity cost for acting slowly ? In averSuch considerations indicate the incompleteness of this previous account of tonic dopamine levels. In particular, dovetailing with our suggestions regarding phasic dopamine above, the suggested mapping of tonic dopamine to the average rate of reward needs to be broadened to include the potentially-achievable rate of safety  which, aIn relation to conditioning in aversive settings, similar complexities arise due to the fact that learning is likely to result in both aversive (i.e. danger-predicting) and appetitive (i.e. safety-predicting) conditioned stimuli, and may promote passive or active defensive strategies. Again, we use dopamine as a medium through which to view these complexities, with its preferential attachment to single sides of these dichotomies.fear conditioning due to the constellation of physiological and behavioural responses that the aversive CS comes to evoke. As in the appetitive case, conditioned and unconditioned responses need not be the same. Take, for instance, the case of conditioning a rat to a footshock US [Conditioning in the aversive case, where animals are exposed to cues predictive of aversive outcomes, is generally known as shock US . Here, tshock US ) as wellThe intricacies of how CR and UR relate to each other, which are arguably greater in the case of fear conditioning where these may be in conflict, may explain some of the difficulties in explicating dopamine’s role in fear conditioning. A role for dopamine in fear conditioning seems to be generally accepted, though there is less consensus on the exact nature of this role (reviews include –267).Electrophysiological studies report that a substantial fraction (35–65 %) of putative dopamine neurons are activated by an aversive CS which is interleaved with an appetitive CS, a fraction that even exceeds the frequency (<15 %) of activations in response to an aversive US . HoweverRegardless of the interpretation of such activations of dopamine cells by aversive CSs, this activity appears to play a role in fear conditioning. For example, Zweifel et al.  have recand increases in NAcC dopamine were observed: an increase on trials in which animals successfully avoided shock, but a decrease on trials in which animals failed to avoid shock.Similar to observations in microdialysis studies of an increase in NAcS dopamine following an aversive US, enhanced NAcS dopamine release is also observed following presentation of an aversive CS . Such en1 receptor agonists and antagonists respectively promote or impede learning and expression in fear conditioning paradigms, while the effect of D2 manipulations is less clear [1 receptors but not of D2 receptors . Consisitioning . Combineitioning –277, as se areas .absence of a US is usually known as ‘conditioned inhibition’ [safety signal [The situation in which a CS predicts the ibition’ , 280. Iny signal , 282. InSuch safety signals are capable of inhibiting fear and stress responses, and are known to have rewarding properties. For example, safety signals have been shown to act as conditioned reinforcers of instrumental responses . This is1/D2 receptors in NAcS—but not in NAcC—disrupted the fear-inhibiting properties of a safety signal. While this finding implicates a role of NAcS in mediating the impact of the safety signal, why these manipulations had similar, as opposed to contrasting, effects is not clear.Neuroscientific study of safety signals is, however, at a relatively early stage . S2 receptors in particular, has long been suggested by the fact that dopamine antagonists interfere with avoidance learning [The final form of learning we consider in detail is instrumental avoidance. This is a rich paradigm that involves many of the behaviours and learning processes that we have discussed so far: innate defence mechanisms, fear conditioning, safety conditioning, and instrumental learning (cf. ). Furthelearning , 292. Inlearning , 12, 248learning , 201 thaA typical avoidance learning experiment involves placing an animal  in an environment in which a warning signal  predicts future experience of an aversive US  unless the animal performs a timely instrumental avoidance response . That animals successfully learn to avoid under such conditions posed a problem that concerned early learning theorists : how canA solution to this ‘problem of avoidance’ has long been suggested in the form of a two-factor theory , 293–296As mentioned above, the importance of innate defensive behaviours in the avoidance context has long been noted. Bolles , highligJust as in the appetitive case, conflict between such Pavlovian behaviours and instrumental contingencies can lead to apparently maladaptive behaviour, albeit in rather unnatural experimental settings. Thus, Seymour et al.  highlighSimilarly, just as it has been suggested that the animal’s appraisal of whether a threat is escapable or not is crucial in determining its defensive strategy in general , it wasThe issue of model-free versus model-based influences has received rather less attention in aversive than appetitive contexts. However, sensitivity to revaluation of aversive USs in the context of instrumental avoidance has been demonstrated in rats , 304 andTwo-factor theories of avoidance fit well with the idea that the striatum, in interaction with dopamine, implements an actor-critic algorithm , 307. ThIt was the abilities of certain antipsychotic drugs and neurotoxic lesions to produce active avoidance learning deficits , 292 tha2 receptors appears of particular importance for this. Evidence from active avoidance studies suggests that while blocking D2 receptors leaves fear conditioning intact, instrumental learning of the avoidance response requires intact D2 signalling [2 receptors therefore does not interfere with the learning of negative state values by the critic but does interfere with the learning of the actor [2 receptor blockade leaves conditioning to aversive stimuli intact in the active avoidance setting is consistent with evidence from fear conditioning studies (see above). Furthermore, that D2 blockade also disrupts instrumental learning is consistent with dopamine’s modulation of direct and indirect pathways in the dorsal striatum, as in Frank’s [2 receptors within dorsal striatum should be implicated more strongly in learning than are those in ventral striatum. A pertinent observation might be a distinction between the longevity of the effects of tying optogenetic stimulation of (D1-expressing) dMSNs and (D2-expressing) iMSNs in the dorsomedial striatum [Dopamine’s action on Dgnalling , 312. Frhe actor . The fin Frank’s  model, sstriatum  of mice.Nevertheless, while many findings accord well with an actor-critic account of avoidance learning, there are at least two omissions in such accounts that require correction. Firstly, similar to Bolles’ complaints about two-factor theory, actor-critic accounts have largely ignored the role for innate  defence mechanisms. Secondly, the key factor of controllability has not been fully integrated with actor-critic models.2 blockade occurs as well as disruption of instrumental learning of the active avoidance response. There are suggestions that suppression of conditioned avoidance may rely more on disruption of D2 signalling within ventral, rather than dorsal, striatum [2 antagonist into NAcS, but not into dorsolateral striatum, leads to a relatively immediate suppression of a conditioned avoidance response [2 activation appears to promote active defensive strategies. Similarly, there is evidence that D2 blockade leads to enhanced freezing responses—arguably, a more passive form of defence—following footshock, interfering with rats’ ability to emit avoidance responses [2 blockade does not disrupt defensive behaviour globally but rather ‘changes the probability that a given class of defensive response will be selected’ In relation to controllability, we have already referred to evidence that exposure to chronic, inescapable stress abolishes stress-induced increases in the concentration of accumbens dopamine –241. SucMore recently, Tye et al.  used optWhile there is evidence from microdialysis studies that support a link between controllability, defensive strategy, and tonic NAc dopamine, it should be noted that not all such evidence points in this direction. For example, Bland et al.  measuredThese latter studies and others –323 high2 system, as a form of canary, since the way that dopamine underpins model-free learning, and model-free and model-based vigour, turns out to be highly revealing for the organization of aversive processing. Our essential explanatory strategy rested on three concepts: safety, opponency, and controllability.Here, we have discussed unconditioned/conditioned, Pavlovian/instrumental, and passive/active issues associated with aversion. We used dopamine, and particularly its projection into the striatum and the DWhen under threat, safety is a desirable state. We suggested that the prospect of possible future safety underlies positive dopamine responses—both tonic and phasic—in response to aversive stimuli. Indeed, the interpretation of these responses is very similar to the more obviously appetitive case involving rewards, since safety is an appetitive outcome. Thus, phasic activation of dopamine cells in response to an aversive stimulus can be interpreted in TD terms as an ‘unpredicted predictor of future safety’. Similarly, increased levels of tonic dopamine in conditions of stress, particularly in NAc, can be interpreted as signalling a potentially-achievable rate of safety.opponent signal is required, marking the value of the path that will (hopefully) not be taken, and providing a new baseline against which to measure outcomes. This results in a form of counterfactual learning signal, a quantity that has also been investigated in purely appetitive contexts, and may have special relevance to the dorsal, rather than the ventral, striatum [Of course, what makes safety a more subtle concept is that it is relative; it is defined in opposition to danger. Dangerous states are not, in general, good states, which is why, in opposition to an appetitive process directed at safety in such states, there should be an aversive system which signals the disutility of occupying dangerous states. Therefore, positive dopamine responses which putatively signal the appetitive component of a TD prediction error in such states can only be part of the story—an striatum –328.Unfortunately, while the notion of opponent appetitive and aversive processes is long-standing , 285, we2-receptor stimulation in particular, modulates active versus passive defensive strategies . Modulation of dopamine in this way raises pressing questions about controllability at both more and less abstract levels. Indeed, even formalizing an adequate concept of behavioural control in the first instance is nontrivial [Whether safety is appraised as achievable or not appears to be crucial, hence our appeal to the concept of controllability. We reviewed evidence that tonic levels of dopamine are modulated downwards over time with chronic exposure to aversive stimuli. Further, we reviewed evidence that dopamine, and NAc Dntrivial .The concept of controllability brings model-based and model-free considerations back into focus since, at least intuitively, this concept seems to imply explicit knowledge of action-outcome statistics in the current environment. In relation to dopamine, this is consistent with evidence that a model-based system could potentially influence model-free learning and performance via the dopaminergic TD signal. However, implementation of heuristics aimed at optimizing the exploration-exploitation trade-off, such as possibly instantiated in a dopaminergic exploration bonus, may provide a model-free proxy for controllability. Thus, further work is required to disentangle the relative contributions of model-based and model-free systems in modulating dopamine signals which, in turn, modulate defensive strategy.2 receptors are particularly prevalent in the central amygdala [2 receptors in the central nucleus is to modulate reflex-like defensive behaviours organised in the brain stem. This clearly relates to the proposed importance of D2 in modulating Pavlovian defence discussed here. Similarly, it is known that stress-induced increases in accumbens dopamine release is constrained by activation of D1 receptors in mPFC, with both mPFC dopamine depletion or blockade of D1 receptors leading to enhanced stress-induced accumbens release of dopamine credit to actions that may have led to aversive outcomes, and (b) to promote suitable (Pavlovian) behaviour prospectively in light of possible future safety.Throughout the review, we have highlighted various issues that merit experimental and theoretical investigation. Experimentally, the most pressing issue is perhaps heterogeneity in the dopamine system—arriving at a clearer view of the potentially separate roles and activation of different groups of dopamine neurons, and reconciling activation and release. Technical advances have allowed increasingly sophisticated attacks on this issue, though a consensus regarding the degree of heterogeneity, both in terms of activity , 334 andSimilarly, it would be important to understand the true degree of separation between putative direct and indirect pathways in the core and shell of the accumbens. Heterogeneity in the serotonin system, and its interactions with dopamine in the case of aversion, would also merit investigation. A recent revealing analysis of active avoidance in the zebrafish, showing the critical involvement of a pathway linking the lateral habenula to the median raphe  is of im2 blockade does not arrest learning aversive predictions even though it does avoidance responses [2 antagonist is washed out—rather leaving it to be acquired slowly, as if it was purely model-free.From a more behavioural viewpoint, it would be interesting to get a clearer view of the scope of model-based aversive conditioning. For instance, take the experiment showing that Desponses : it is nAnother important experimental avenue is to try and integrate the processing of costs  with that of actual punishment. Costs, which could be either physical or mental –342, alsFrom a more theoretical viewpoint, perhaps the most urgent question concerns pinning down the different facets of controllability, the way that these determine operations such as exploration, and relative model-based and model-free influences. Entropy and reachability of outcomes were considered by , but othA further direction is to construct a more comprehensive theory of aversive vigour  looked aFinally, we have noted various structural asymmetries between appetitive and aversive systems, ascribing many of them to asymmetric priors about the structure of rewards and punishments in environments . It woulIn conclusion, we have attempted to use our evolving and rich view of the nature and source of learned, appetitive behaviour to examine the case of aversion and defence. Along with substantial commonalities between the two, we have discussed some critical differences—notably in the way that aversive behaviour appears to piggy-back on appetitive processing, leading to various intricate complexities that are incompletely understood. Dopamine plays a number of critical and apparently confounded roles; we therefore used it to lay as bare as possible the extent and limits of our current understanding.


TP53 mutation. Here we show that the sub-cellular localization of the WRAP53 protein has a significant impact on breast cancer survival, and thus has a potential as a clinical marker in diagnostics and treatment.WRAP53 protein controls intracellular trafficking of DNA repair proteins, the telomerase enzyme, and splicing factors. Functional loss of the protein has been linked to carcinogenesis, premature aging and neurodegeneration. The aim of this study was to investigate the prognostic significance of WRAP53 protein expression in breast cancer. A tissue microarray was constructed from primary breast tumors and immunostained by a polyclonal WRAP53 antibody to assess the protein expression pattern. Two different patient cohorts with long term follow-up were studied; a test- and a validation set of 154 and 668 breast tumor samples respectively. Breast cancer patients with tumor cells lacking the expression of WRAP53 in the nucleus had a significantly poorer outcome compared to patients with tumor cells expressing this protein in the nuclei . Nuclear localization of WRAP53 was further shown to be an independent marker of prognosis in multivariate analysis , and also significantly associated with better outcome in patients with  WRAP53 gene, which has a genomic location in head-to-head arrangement with the TP53 gene on 17p13.1[The WRAP53 protein is encoded by the n 17p13.1–4.Depletn 17p13.1. In addiTP53 and its flanking genes, where single nucleotide polymorphisms  was suggested to be associated with increased risk for developing Estrogen Receptor (ER) negative breast carcinomas[WRAP53 gene, resulting in impaired function of WRAP53, cause the cancer predisposition disorder dyskeratosis congenita[in press). Similarly, loss of nuclear WRAP53 associates with poor prognosis in head and neck cancer[WRAP53 was first implicated in cancer in an extensive re-sequence analysis of arcinomas. The SNPcongenita. A role congenita,12. WRAPcongenita. Downregcongenita, in presck cancer.Here, we have analyzed WRAP53 protein expression in breast carcinomas and show that the sub-cellular localization of the protein has an impact on the mortality of breast cancer patients.The study cohort consists of 154 out of 212 primary breast tumor samples sequentially collected at Ullevål University Hospital, Norway from 1990 to 1994 (termed A tissue microarray (TMA) was constructed from formalin fixed and paraffin embedded primary breast tumor tissue  and consisted of three 0.6 mm paraffin cores from each individual tumor (selecting the most aggressive components and minimum of non infiltrating components), that altogether constituted five recipient paraffin blocks. TMA for the validation set (n = 668) was constructed following the similar procedure, but with two cores from each individual tumor that altogether constituted eight recipient paraffin blocks.+ System–HRP (DAB) kit  and Dako Autostainer following manufacturer’s standard procedure. Following treatment with a peroxidase block, the TMA sections were immunostained with WRAP53-C1 primary antibodies (diluted 1:1000) and subsequently with secondary antibody; peroxidase-labelled polymer conjugated to goat anti-rabbit immunoglobulins. HIER procedure for the validation set was performed in a water bath based Dako PTLink instrument using EnVisionTM FLEX Target Retrieval solution, Low pH (corresponds to citrate-buffer pH6). The sections were stained with WRAP53 antibody (diluted 1:500) using Dako EnVisionTM Flex+ system. For signal amplification, the sections were further incubated with EnVisionTM Flex+ rabbit LINKER. The immunostained sections  were then visualized with 3’3 diaminobenzidine tetrachloride (DAB), a chromogenic reporter DAB, counterstained with hematoxylin, dehydrated and cover-slipped with Richard-Allan Scientific Cytoseal XYL .The TMA sections were immunostained by a rabbit polyclonal WRAP53 antibody , targeted against amino acids 483–496 of full length WRAP53 protein. The antibody specifically detects WRAP53 protein in cells as affirmed by western blot analysis [The stained sections in both the test- and validation set were visually inspected and scored in random order for the WRAP53 protein expression using light microscopy. The criteria for a sample to be scorable were set to the presence of at least one core containing at least 50 intact tumor cells. Some internal background was noticed for several samples and if the intensity of such cytoplasmatic staining was above the level of staining in other cell types it was scored as positive. WRAP53 expression in nucleus and cytoplasm were scored separately and the samples were categorized based on the fraction of stained cells . Samples with below 5% positively stained cells were considered negative for protein expression. For patients with discrepant results between the individual cores from the same tumor, the core with highest percentage of positively stained cells was taken into account. The semi quantitative scoring criteria were established by two pathologists, and cases with discrepant results were discussed to obtain consensus.2) test and Fisher’s exact test were used when appropriate to test association between different variables.All statistical analysis were performed using R version 3.0 with the package ‘rms’. SurvivaWRAP53 gene.The WRAP53 protein was found to localize both in the nucleus and the cytoplasm of the breast carcinoma cells, separately or in combination . A substIn the test set, WRAP53 protein expression did not demonstrate a statistically significant association with any of the commonly used clinico-pathological and molecular markers . In the Univariate survival analysis showed that breast cancer patients with negative nuclear staining of the WRAP53 protein had a statistically significantly increased mortality compared to patients with positive nuclear staining  of WRAP53 prevented formation of Cajal bodies and resulted in more dispersed localization of the protein in the nucleoplasm instead of its normal accumulation in Cajal bodies[The role of WRAP53 in formation and maintenance of Cajal bodies is largely affected by its proper localization. Mahmoudi al bodies. This imin press).The WRAP53 protein has recently been shown to regulate the assembly of repair factors at sites of DNA damage. Consequently, loss of this protein was found to disturb repair of DNA double-strand break and resulted in the accumulation of spontaneous DNA breaks–21. InvoAberrant localization of proteins may be caused by mutation, altered expression of cargo proteins or deregulated trafficking machinery, and contributes to the pathogenesis of many human diseases, such as cancer (reviewed in ). ConsisTP53 mutation status) that could have an increased clinical benefit of nuclear WRAP53. Nuclear WRAP53 predicted outcome in the ER negative subgroup and in the TP53 mutated group in the test set. In the validation set, significant prognostic effect was observed in ER positive and in bothTP53 mutated and TP53 wildtype group. These differences can partly be explained by the differences between the two cohorts, where the tumors in the test set overall can be characterized as more aggressive and advanced than those in the validation set. Also, the larger sample size of the validation cohort may have allowed discovering the subtle associations, which, in the test set, could not be discovered due to smaller patient cohort. Another important discrepancy is the prognostic effect of ER status and TP53 mutation status in these two cohorts. While, ER-status is not prognostic in the test set, it is highly prognostic in the validation set, whereas the opposite is true for TP53 mutation status. Thus far, there has not been reported any direct associations between TP53 and WRAP53 at the protein level. The sense-antisense posttranscriptional regulatory relationship between TP53 mRNA and the overlapping isoform WRAP53α observed in cell-lines[TP53 mutated group in the test set, which is a poor prognosis group and lacks robust prognosis markers; the finding calls for further validation.The association of WRAP53 with some clinicopathological variables  was observed only in the validation set. Furthermore, our study does not define a patient group Click here for additional data file.S1 Table(XLSX)Click here for additional data file.S2 Table(XLSX)Click here for additional data file.S3 Table(XLSX)Click here for additional data file.S4 Table(XLSX)Click here for additional data file.S5 Table(XLSX)Click here for additional data file.


M. bovis by PCR, with an overall prevalence of 29.16% and 8.33%, respectively. Female had a higher prevalence rate than male cattle at 16.66% and 12.5 % by ZN and 5.00% and 3.33% by PCR, respectively . However, there was a statistically significant association  between detection of bTB and the age of cattle. ZN revealed that cattle aged 6 years and above had the highest number of positive bTB cases 67.9%, while cattle aged 3–5 years had the lowest 14.81%. PCR technique revealed that the cattle aged 6 and above years also had the highest percentage positive M. bovis cases of 22.84%, whereas cattle aged 3–5 years had the lowest and the overall prevalence rate of 8.33%. The study found a high infection rate of bTB among cattle and majority of the lesions 54.2% were from lungs. The prevalence of bTB was higher in Bauchi metropolitan abattoir which supplies larger population of the state with beef.Bovine tuberculosis is a chronic, infectious, and contagious zoonotic disease of domestic animals, wild animals, and humans. It also poses a public health threat and economic losses. This study was aimed at determining the prevalence of bovine tuberculosis in slaughtered cattle, based on PM meat inspection, Ziehl-Neelsen staining, and PCR techniques in Bauchi State, Nigeria. A Prospective study was conducted on 800 cattle slaughtered in the three Zonal abattoirs of Bauchi State, Nigeria. One hundred and twenty (15%) tissues from different organs had suspected bTB lesions at PM. Out of the samples examined 35 (29.2%) were AFB positive by ZN and 10 (8.3%) were confirmed positive for Bovine tuberculosis (bTB) is a chronic infectious and contagious zoonotic disease of domestic animals, wild animals, and humans . It also Mycobacterium bovis (bovine tubercle bacillus) which is a member of Mycobacterium tuberculosis complex [ Mycobacterium tuberculosis complex (MTBC), include Mycobacterium tuberculosis, M. bovis, M. microti, M. caprae, M. africanum, M. canettii, and M. pinnipedii. Mycobacterium africanum consists of a rather heterogeneous group of strains isolated from humans in Africa [Bovine tuberculosis is caused by complex , 8. The n Africa . The orgn Africa . Cattle n Africa .Bovine TB in cattle is initially asymptomatic and, prior to testing, farmers usually remain unaware of the outbreak during this stage. It can take as long as a few years before any signs can be observed. As the infection progresses in cattle, bovine tuberculosis causes a slight fever and roughened hair coat and the lymph nodes usually swell or have abscesses and show signs of dyspnoea with an associated cough. The cow will appear weak, show signs of laboured breathing, and have an increased breathing rate. A loss of appetite will be noticed and the decrease in weight may be so significant that the cow actually becomes emaciated. Tuberculosis (TB) in humans is characterized by prolonged coughing, general body weakness, wasting, and sweating at night with slight fever .In UK, badgers have been culled since 1971, when a tuberculous dead badger was found in an infected farm. Bovine TB control has proved difficult to achieve where there is a persistent reservoir of infection in wildlife . ConsequDespite the availability of effective therapy, tuberculosis remains a major public health problem worldwide , 17. FacRecent advances in the treatment of human TB have permitted effective management of cases on an ambulatory basis . However2 (250/sqmi) and per capita income of $983 [Bauchi State occupies a total land area of 49,119 Km² representing about 5.3% of Nigeria's total land mass and is located between latitudes 9°3′ and 12°3′ north of the equator and longitudes 8°50′ and 11° east of the Greenwich Meridean . The sta of $983 . Bauchi The three major slaughter houses, namely, Bauchi, Misau, and Katagum (Azare), in each of the three senatorial zones of Bauchi State were selected for the study for sampling purposes, based on their daily slaughter capacity and socioeconomic impact of the abattoir. Accordingly, out of the 800 head of cattle examined (sample size), a proportionate distribution was employed, given 50% (400) to Bauchi abattoir and 25% (200), each, to Katagum and Misau slaughter houses. This was based on their daily slaughter capacity of 40–60, 20–30, and 20–25 head of cattle from Bauchi abattoir, Katagum, and Misau slaughter houses, respectively. The selection of the cattle sampled at each of the abattoirs was strictly on the basis of the age of the cattle (meant for slaughter and three years above), following then PM observation of typical granulomatous bTB lesions in any of the visceral organs before the cattle is considered a case and sample.Most of the animals brought for slaughter were mainly sourced from Maiduguri, Chad, and Niger.Identification of cases was based on presence of typical tubercle, yellowish, granulomatous, and caseous lesions in the lungs, lymph nodes, kidneys, intestines, and liver . Aging o M. bovis, as described by [A total of 800 head of slaughtered cattle were examined at postmortem for TB lesions. Using a convenience sampling, a total of 400 head of cattle from Bauchi, 200 head of cattle each from Misau and Katagum LGA slaughter houses were examined. One hundred and twenty (120) tissue samples were collected from cattle with suspected TB lesions into sterile screw-capped containers  and transported inside a cooler containing ice pack to the Veterinary Public Health Bacterial Zoonoses Laboratory, Ahmadu Bello University, Zaria, and stored at −20°C until analysis was carried out. Stored samples were processed  for microscopic examination (modified Ziehl-Neelsen staining technique) and only AFB positive samples were taken to the DNA Labs, Kaduna, and used for conventional PCR amplification protocols specific forribed by .Ziehl-Neelsen staining (“Hot” ZN technique) was carried out on the tissues stored at −20°C after thawing them to room temperature using standard protocol for mycobacterial identification of  to detecDirect smears were prepared from tissues presenting tuberculous lesions using Ziehl-Neelsen staining/acid fast technique. The collected samples were crushed using a pestle in a clean mortar and homogenized using a stomacher. The crushed tissues were placed on a new, clean, and labelled grease-free glass slide and spread with a sterile pipette tip to make a smear (1 cm × 2 cm). The smeared slides were air-dried and heat-fixed by passing them gently over the flame (Bunsen burner) with the specimen side up. This fixed the specimen to the slide and preserved the bacterial morphology.Direct smears were prepared. The crushed tissues were placed on a grease-free glass slide to make a smear (1 cm × 2 cm). The smears were then stained with carbol fuchsin and allowed to stand for 5 minutes. The stained smear was washed with tap water (to remove excess stain from the slide). The slide was decolourized with 3% acid alcohol. After decolourization, the slide was counterstained with methylene blue for 1 minute. Additional rinsing was done with water to remove excess colour and the slide was allowed to air-dry. Finally, the slide was viewed in an optical microscope (×100—an oil emersion objective). Results were that acid fast bacilli appeared red. A red, straight or slightly curved rod occurring singly or in a cluster indicates the presence of tubercle bacilli.μL of 1x Tris-Borate (1× TBE) buffer and DNA was precipitated with ethanol, collected by centrifugation and dissolved in 50 μL of distilled water. 5 μL of the extracted DNA was run on 1.0% agarose gel and spectrophotometer to confirm the presence of DNA. The remaining DNA samples were stored at −20°C until further use.The tissue samples positive by ZN were collected into a 1.5 mL microfuge tube containing lysis buffer, stored at room temperature, and transported on ice pack to DNA Labs, Kaduna. About 1 g of the tissue sample was homogenized with pestle and mortar for chromosomal DNA extraction using a phenol-chloroform technique as described by , 27. The Mycobacterium bovis genome. The primers were synthesized based on the G+C contents of the Mycobacterium bovis strains available at the gene bank of the Bioneer, USA [eer, USA .2 were used. All amplification reactions were performed using a Perkin Elmer Thermocycler (Perkin Elmer Cetus) programmed for 40 amplification cycles [μL containing 10 μL of DNA template, 1x TBE (1x Tris-Borate) reaction buffer (containing 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 1.3 mM MgCl2, and 0.001% of gelatin), 2.5 U Taq polymerase, 0.2 mM of each deoxynucleoside triphosphate, and 75 pmol of each primer , 40 amplification cycles were performed as follows: denaturation at 94°C for 1 min, annealing at 58°C for 30 sec, and extension at 72°C for 30 sec, with an increment of 1 sec per cycle for the denaturation and extension segment. A final extension was performed at 72°C for 15 min.Ten (10) microlitres suspended DNA was used as a template for PCR amplification under standard conditions as described by . A commen cycles , 30. Theh primer . DNA froµL of the PCR product was loaded with gel loading buffer in a 1% agarose gel  containing 0.5 pug/mL ethidium bromide. The gel was also loaded with the 100 base pair (bp) DNA molecular marker (ladder). Gel electrophoresis was done at a 5 v/cm for 1 hour. Finally, after electrophoresis, the DNA bands were visualized (using UV light box or gel imaging system) and photographed.After amplification, 20 χ2) was used to determine association between variables and M. bovis infection. Odds ratio (OR) and 95% confidence interval were calculated to measure the strengths of associations between variables and bTB (M. bovis). Values of P < 0.05 were considered significant.Descriptive statistical tables and bar charts were constructed using Microsoft Excel 2010. The data were also analysed using statistical package for social sciences (SPSS) version 20.0. Chi-square , followed by the lymph nodes 7.14% (2/28) and then the intestines and the liver had the least number of positives for bTB (M. bovis), while the spleen, heart, and mammary gland were all negative for bTB  tissues from different organs were suspected to have bTB lesions. Out of the 120 tissues, thirty-five 29.16% 35) were positive for bTB using Ziehl-Neelsen staining technique  and gave5 were po for bTB .P < 0.05; χ2 = 4.623, OR = 3.680) association between detection of the bTB in the tissues using ZN and the age of cattle  association between detection of bTB in the tissues and the age of the cattle. Cattle aged six (6) years had a prevalence rate of 8.33%, while cattle aged 3–5 years were negative for bTB using PCR method.There was a statistically significant  between the presence of bTB in the tissues sampled and the sex of the cattle using ZN method. However, the female cattle had higher prevalence and sex-specific rates than the male cattle sampled   . M. bovis. The infection rates were higher in females than in males. By the confirmatory PCR, the overall prevalence rate of M. bovis (bTB) in Bauchi State was 8.33%.The prevalence rates of bTB found in this present study based on ZN and confirmatory PCR were 29.16% and 8.33%, respectively. This study also showed that PCR is a highly sensitive and specific  test that can be adapted as a confirmatory test to conventional tests such as PM, tuberculin skin test (TST), and ZN because of its ability to rule out possible false positive results associated with these tests. However, ZN has the ability to detect more AFB positive samples as fastidious organisms that may be present in the granulomatous lesions obtained from slaughtered cattle. This agreed with the previous report by  using ZNThe findings that 120 (15%) bTB suspected lesions were observed in the 800 head of slaughtered cattle examined in Bauchi State abattoirs had emphasized the importance of PM meat inspection. This agrees with the report of , as postThe distribution and occurrence of suspected bTB lesions in different organs of slaughtered cattle in Bauchi State showed 54.20% (65/120) in the lungs and 23.30% (28/120) in the lymph nodes, while the heart, liver, spleen, intestines, and mammary glands made up the least number of bTB positives. This agreed with the retrospective study reported by  on gross M. bovis alone, as other MTBC and AFB organisms may cause bTB-like lesions which were excluded by PCR.The present study estimated the prevalence rate of bTB in Bauchi State, using PM, ZN, and PCR techniques at . Bovine TB lesions found at PM were not all due to M. africanum.Proper PM meat inspection should be practiced efficiently at the abattoir and slaughter houses, before taking beef to the public. The emergence MDR and XDR-TB strains are also a major concern in Nigeria. Thus, further molecular epidemiological studies with more improved techniques, like MIRU-VNTR and spoligotyping, should be carried out on isolates from the state to look for other zoonotics, like


The Internet is one of the most key technical infrastructures in existence today. It will be a catalyst for much of our innovation and prosperity in the future. However, the present Internet may not be capable of meeting so many requests much longer. Fortunately, scientists and engineers believe that new technologies, protocols, and standards can be developed to meet tomorrow's demands. The research on this new Internet is considered as a global research challenge. Therefore, we have organized a special issue for researchers, engineers, and practitioners to share their work on next-generation Internet technologies.Nowadays, the researches about next-generation Internet mostly focus on the design, engineering, protocols, and operation the of the new signal processing techniques in 3G/4G/B4G/LTE , 2, Ad HThe papers in this special issue of next-generation Internet and communication cover a wide range of topics from underlying infrastructure and protocols to high-level systems design and analysis.The new signal processing techniques in 3G/4G/B4G/LTE are a hot issue, and for this topic, we accepted three papers. They talk about the channel allocation and transmission problems in LTE.Ad Hoc Network/Wireless Mesh Network has been a hot topic for several years and it is still a hot topic. The Wireless Mesh Network is Ad Hoc Network essentially, so we regard them as one topic. We accepted seven papers for this topic. They focus on the routing protocols and data delivery method in Ad Hoc Network or Wireless Mesh Network and propose some new routing protocols, such as a source-initiated on-demand routing algorithm.Another important topic is channel allocation. We accepted six papers for this topic, including a paper about routing scheme. They talk about how to gain the network transfer capacity.Security is another basic issue. For this topic, we accepted two papers. One is about defense model based on fuzzy evaluation. In the paper, first, the authors propose a distributed network security architecture, comprising a hybrid firewall, intrusion detection, virtual honey net projects, and connectivity and interactivity between these three components. The other one is about multiple-feature extracting modules. In the paper, they implement a crawler mining system that is equipped with SQL injection vulnerability detection, by means of an algorithm developed for the web crawler.Cloud computing and IoT are very hot in recent years. We accepted two papers. One is about cloud computing. In the paper, the authors propose a novel unfair rating filtering method for a reputation revision system using prior knowledge as the basis of similarity when calculating the average rating, which facilitates the recognition and filtering of unfair ratings. The other one is about IOT. IOT accumulates large amounts of data by IOT users, which is a great challenge to mining useful knowledge from IOT. Classification is an effective strategy which can predict the need of users in IOT. In the paper, a new rule-based classification is proposed.All the researches about Internet are for the purpose of getting better services, so the services of Internet are also important topics. For this topic, we accepted three papers. They are about social network, content centric Internet, and power WebGIS platform.We hope that readers will find in this special issue not only the new ideas, cutting-edge information, new technologies, and applications of next-generation Internet and communication, but also a special emphasis on how to solve various problems.Weifeng  SunWeifeng  SunGuoqiang  ZhangGuoqiang  ZhangJingjing  ZhouJingjing  ZhouVijay  BhuseVijay  Bhuse


Vibrio vulnificus, a gram-negative bacterial pathogen, causes high mortality of aquaculture fishes upon infection. Humans can become infected with V. vulnificus through open wounds or by eating raw seafood, and such infections may result in systemic septicemia. Moreover, patients with liver diseases are vulnerable to infection, and are more likely than healthy persons to present with liver inflammation following infection. This study quantified n-3 PUFAs and their anti-bacterial effects in Fadsd6 and Elvol5a transgenic zebrafish.Highly desaturated n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are synthesized by desaturases and elongase. They exert hepatoprotective effects to prevent alcoholic fatty liver syndrome or cholestatic liver injury. However, it is unclear how n-3 PUFAs improve immune function in liver. Fabp10 promoter) were established using the Tol2 system. Synthesis of n-3 PUFAs in these strains were increased by 2.5-fold as compared to wild type (Wt) fish. The survival rate in 24 h following challenge with V. vulnificus was 20 % in Wt, but 70 % in the transgenic strains. In addition, the bacteria counts in transgenic fish strains were significantly decreased. The expression levels of pro-inflammatory genes, such as TNF-α, IL-1β, and NF-κB, were suppressed between 9 and 12 h after challenge. This study confirms the anti-bacterial function of n-3 PUFAs in a transgenic zebrafish model.Two transgenic zebrafish strains with strong liver specific expression of Fadsd6 and Elvol5a  contains supplementary material, which is available to authorized users. Docosahexaenoic acid DHA, 22: 6 n-3) and eicosapentaenoic acid EPA, 20:5 n-3) are formed through desaturation and elongation of α-linolenic acid ALA, 18: 3 n-3), as catalyzed by pivotal desaturases and elongase [8: 3 n-3,2: 6 n-3  n-3 are 2 to enhance inflammation. In contrast, the other substrate for COX is EPA, which is not only an inhibitor of AA metabolism, but also an alternative substrate for COX-mediated synthesis of PGH3, an anti-inflammatory cytokine. Furthermore, other inflammatory mediators, such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), are inhibited by EPA [Various n-3 PUFAs have been reported to exert beneficial effects, such as protection against liver diseases, regulation of cholesterol, and reduction of blood pressure, which prevents cardiovascular diseases (CVDs) , 10. On d by EPA . Hence, d by EPA .Propionibacterium acnes and Staphylococcus aureus [EPA and DHA also exhibit significant anti-bacterial effects against s aureus . In 2005s aureus . These fVibrio vulnificus (V. vulnificus) is a gram-negative bacterium which causes infectious disease and striking mortality, mostly due to septicemia [V. vulnificus infection is associated with high mortality [V. vulnificus induces the host immune response through TLRs and their downstream genes, NF-κB, which translocates to the nucleus and leads to inflammation [pticemia . Infectiortality . Moreoveortality . On the ortality . V. vulnammation , 22.V. vulnificus [Fadsd6 and Elvol5a in transgenic zebrafish exerts protection from V. vulnificus infection. Our findings suggest that liver-specific expression of Fadsd6 or Elvol5a enhances the bio-synthesis of EPA and DHA in transgenic zebrafish, and this is sufficient to increase the survival rate in response to V. vulnificus challenge.Most fresh water fish lack the n-3 PUFAs and can’t protect from bacterial infection. We try to increase the n-3 PUFAs by transgenic fish. Because the liver is the major organ for lipid metabolism, it is also a target of lnificus . Accordilnificus . In thisDanio rerio) was maintained under standard conditions (water-flow tanks at 28.5 °C with a 12 h light/12 h dark cycle). Zebrafish was fed on a commercial diet twice a day. The embryos were collected through natural matching and cultured in a 28.5 °C incubator. All conditions for maintaining zebrafish were as previously described  [Wild-type (AB) zebrafish  .Research was conducted in compliance with the principles stated in the Guide for the Care and Use of Laboratory Animals, National Research Council, 1996. All animal experiments in this study were approved by the Academia Sinica Institutional Animal Care & Utilization Committee (AS IACUC).Fabp10 promoter, which was used to drive a tetracycline-controlled transactivator (tTA) and either the TcFP13 (GFP) or TcFP11 (RFP) reporter genes. The Fadsd6 and Elvol5a genes of Atlantic salmon  were individually flanked by the Tol2 transposon element, and placed downstream of the tetracycline responsive element. This liver-specific gene expression system was modified from that described in our previous publication [Plasmids contained the lication .Transposase messenger RNA (mRNA) was co-injected with vectors into embryos (at the one-cell stage), and excision efficiency assays were performed as described . Injecte-ΔΔCT) for each gene by subtracting the ΔCT value of the control sample from that of the infected sample (i.e. ΔΔCT). Values are presented as relative fold expression levels with the standard error; results from at least three independent experiments were averaged.RNA from zebrafish liver tissue was extracted with TRIzol reagent (Invitrogen) and reverse transcribed to cDNA using the High Capacity cDNA Reverse Transcription Kit (Applied Biosystems). Quantitative real time-PCR was performed using a LightCycler480 system . The Q-PCR synthesis mix reagents included 5 μL Master Buffer (Roche Applied Science), 2 μL each primer (2 μM), 0.1 μL probe  and added to 500 μL 2-D rehydration sample buffer with 5 μL ready prep TBP reducing agent . After centrifugation at top speed for 20 min at 18 °C, 300 μL supernatants were collected and transferred to new 1.5 mL microcentrifuge tubes, and kept at -80 °C for long-term storage. Protein concentrations were determined using a Protein Assay Kit . For Western blot, protein samples (100 mg) were separated using the NuPAGE Bis-Tris Mini Gel Kit (Invitrogen) and transferred to a 0.45 nm PVDF membrane  using a trans-blot SD cell (Bio-Rad). Membranes were blocked with 5 % milk (Anker) for 1 h, and then rinsed three times with PBS (Bioman) for 5 min with shaking; next, membranes were incubated with primary Anti-V5 antibody  overnight at 4 °C. Samples were incubated with β-actin antibody  as an internal control; after washing to remove excess antibody, samples were incubated with secondary antibody  for 1 h at room temperature with shaking, and then washed as described above. Membranes were exposed to Immobile Western Chemiluminescent HRP Substrate (Millipore), and proteins were then detected using an Imaging System (UVP).3-MeOH 7 %  and boiling stones for 40 min (reflux at 90 °C). Subsequently, 5 mL hexane (Sigma) was added, and the sample was incubated for an additional 1 min. Fatty acid methyl esters (approximately 5 mL) were dried and diluted with highly pure hexane (100 mg/mL). The samples were analyzed using an Agilent 5975C Series GC-MSD (Agilent). The Agilent column was 30 mm X 0.25 mm, with a film thickness of 0.25 mm ; conditions were as previously described  [For fatty acid analysis of transgenic lines and wild-type zebrafish, total lipids were extracted with organic solvent , using a previously described method  . Crude lu, 2009) .V. vulnificus was cultured on BHI  agar plates containing 1.5 % w/v sodium chloride (Merck) in a 30 °C incubator for 16 h. A single colony of V. vulnificus was subsequently incubated in 300 mL BHI (NaCl 1.5 %) media in a 30 °C incubator on a shaker operating at 200 rpm for a further 16 h. Subsequently, 30 μl of bacteria were cultured with 300 μL of BHI (NaCl 1.5 % w/v) media in a 30 °C incubator on a shaker operating at 200 rpm to obtain the appropriate concentration (107 CFU/mL).V. vulnificus . Five fish were sacrificed at 0, 1, 3, 6, 9, 12, 24, and 48 h after challenge for each group.Wild-type and transgenic zebrafish were challenged by intraperitoneal injection of 10 μL V. vulnificus colonies were then counted.Liver samples were homogenized in BHI  media, and the supernatants were serially diluted in BHI  media. Ten microliters of each dilution were spotted onto a TCBS  plate. Plates were incubated in a 30 °C incubator for 16 h, and V. vulnificus was detected by subjecting paraffin-embedded sections to the TUNEL assay, using the In Situ Cell Death Detection kit, POD (Roche Applied Science).Liver tissue was fixed with 10 % neutral formalin (Sigma) and embedded in paraffin. Sections with a thickness of 5 mm were prepared, and then stained with hematoxylin and eosin  for histological examination. DNA damage resulting from challenge with t-test, and significance was set at *P < 0.05, **P < 0.01.The expression values of all the data are presented as the average ± standard deviation (SD). Statistical analysis was performed using Student’s Fabp10 promoter, which was used to drive a tetracycline-controlled transactivator (tTA) and either the TcFP13 (GFP) or TcFP11 (RFP) reporter genes. The Fadsd6 and Elvol5a genes of Atlantic salmon  were flanked by the Tol2 transposon element, and placed downstream of the tetracycline responsive element . One group of Wt fish was injected with 10 μL 1X PBS as a negative control. Each group contained at least 30 fish for one test. Fish mortality was determined at 0, 1, 3, 6, 9, 12, 18, 24, and 48 h after challenge.We proceeded to examine whether high n-3 PUFA contents suppress bacterial infection. The bodies of transgenic and Wt fish were IP-injected with 10 μL V. vulnificus. However, both two transgenic fish showed slight bleeding. The skin looks quite smooth as normal fish , lymphocyte infiltration, and extensive monocyte recruitment were observed within the livers of Wt fish. However, Fadsd6 and Elvol5a transgenic fish did not exhibit substantial damage after infection  the liver is the major organ for lipid metabolism; (2) Fadsd6 has been shown to be rate limiting for the conversion of ALA to EPA in the lipid biosynthesis pathway; and (3) Elvol5a improves the production of DHA and DPA in the n-3 PUFA biosynthesis pathway [Long-chain n-3 PUFAs, such as EPA and DHA, are well-known to have many beneficial effects on biological functions. However, total fat content and the ratio of n-3 to n-6 PUFAs in food have decreased significantly since the Industrial Revolution . Moreove pathway , 34. Whe3 [in vitro studies have indicated that EPA suppresses the growth of Staphylococcus aureus and Propionibacterium acnes [Vibrio alginolyticus growth [A separate study showed that increasing n-3 PUFA content reduced the generation of eicosanoids from AA and promoted the generation of PGH3 . These num acnes , 36. It s growth .V. vulnificus causes serious, fulminant sepsis, mostly in patients with chronic liver diseases. After reaching the blood stream, the bacteria begin to proliferate and produce two main cytotoxins, VvhA and MARTXvv. VvhA, a haemolysin, is cytotoxic to host cells by causing necrosis or apoptosis depending on the amount of bacteria which cells exposure. MARTXvv is required for V. vulnificus survival during infection by protecting itself from swallowing by phagocytes. Both cytotoxins build a microenvironment for V. vulnificus to facilitate bacterial dissemination and contribute to tissue damage [V. vulnificus infection, with repressed growth of V. vulnificus in the liver resulting in decreased mortality and reduced hepatocyte damage. Further, the bacterial contents in Wt liver were higher than in muscle (Fig. V. vulnificus caused haemolysis and iron availability has been found to be related in pathogenic vibrios with haemolysin production [V. vulnificus infection [e damage . To elucoduction . In addioduction . In clinnfection . TherefoV. vulnificus infection [V. vulnificus infection (Fig. 3. Anti-inflammatory cytokines may be elevated to diminish the inflammatory response after V. vulnificus infection.NF-κB is activated by nfection . The pronfection . Howevernfection . In agreion Fig. . In addiV. vulnificus as compared to transgenic fish. Expression of these factors can facilitate the removal of pathogen and increase the survival rate after infection. In addition, previous study demonstrated the potency of anti-bacteria of DHA is the highest than other long chain PUFAs [Moreover, IL-15 and lysozyme are secreted by macrophages and recruited to sites of infection to clear pathogens . The expin vivo model for studying the bio-function of n-3 PUFAs, and for increasing EPA and DHA production in aquaculture fish to confer anti-bacterial and/or cold resistance. High n-3 PUFA content zebrafish may also provide a convenient platform with which to study the molecular mechanisms behind potentially lethal inflammation and septicemia due to V. vulnificus infection in human.In summary, the transgenic fish described here can be used as an V. vulnificus infection, with enhanced survival and anti-inflammatory effects. Moreover, these transgenic lines may serve as an in vivo model for studying the effects of n-3 PUFAs on bacterial infection and inflammation-associated diseases.In this study, liver-specific expression of salmon Fadsd6 or Elvol5a in transgenic fish was shown to enhance the bio-synthesis of n-3 PUFAs. Furthermore, transgenic fish exhibited resistance to


Kaposi’s sarcoma (KS) is an angioproliferative disease frequently seen in patients with the acquired immunodeficiency syndrome (AIDS). Previous studies suggest that the HIV-1 protein Tat and Fibroblast Growth Factor 2 (FGF-2) have synergistic angiogenic effects in AIDS-KS tumors. However, the mechanisms by which FGF-2 is released and activated in KS tumors are not clearly defined. We carried out this study to determine whether an FGF-binding protein (FGFBP1 or BP1) that enhances the angiogenic activity of FGF-2 is expressed in AIDS-KS tumors, and to define whether BP1, FGF-2, and HIV-Tat protein-protein interactions could play a potential clinically role in the pathogenesis of AIDS-KS.BP1 was localized in AIDS-KS lesions by immunohistochemistry and in situ hybridization studies. The binding of radiolabeled FGF-2 to His-tagged BP1 or the FGF-receptor 1 was assessed in the presence and absence of HIV-Tat and other viral proteins. Mice carrying tetracycline-regulated BP1 transgene mice were used to determine whether activation of BP1 during wound healing induces KS-like lesions.BP1 expression was detected in AIDS-KS tumor keratinocytes, spindle cells, and infiltrating mononuclear cells. In addition, HIV-Tat competed for the binding of FGF-2 to immobilized BP1, but does not affect the interactions of FGF-2 with its high affinity receptor (FGFR-1). In contrast, two other HIV-proteins, Nef and gp120, did not affect the binding of FGF-2 to BP1 or to FGFR-1. Finally, up-regulation of BP1 expression in tetracycline-regulated –conditional BP1 transgenic mice subjected to skin wounds, induced KS-like skin lesions.in vitro and in vivo, our findings suggest a novel mechanism by which the release and activity of FGFs can be modulated in AIDS-KS tumors by HIV-Tat as well as BP1.Taking into consideration the results of previous studies showing that both HIV-Tat and BP1 enhance the mitogenic and angiogenic activity of locally-stored FGF-2, both  Kaposi’s Sarcoma (KS) is an angiogenic multifocal proliferative tumor which can arise in the skin, mucosa surfaces, and internal organs . ElderlyAmong the many cytokines accumulated in KS lesions, Fibroblast Growth Factor 2 (FGF-2 or basic FGF), plays an important role in the pathogenesis of KS ,6. FGF-2This study was approved by the Institutional Review Board from the Children’s National Medical Center. The diagnosis of HIV-1 infection and KS were done by the attending physicians following standard clinical and pathologic criteria. KS tissues were obtained from biopsies or autopsies of patients with AIDS-KS lesions in the skin (n =2), lung (n=1), gastrointestinal tract (n=1), and from one KS tumor harvested from the skin of an HIV-negative patients. Control sections were obtained from AIDS patients without KS: skin (n =2); liver (n=1), lung (n=1), gastrointestinal tract (n=1).Tissues were fixed in 10% neutral buffered formalin and embedded in paraffin. Paraffin sections were cut at 4 μm, deparaffinized and rehydrated. Sections were then heated twice for 5 min each in 0.01 M sodium citrate (pH 6.0) in a microwave oven  to augment antigen retrieval. Endogenous peroxidase activity was blocked by treating with 3% H2O2 in 100% methanol for 10 min. Immunostaining was performed with a commercial streptavidin-biotin-peroxidase complex HistostainTM SP kit  according to the manufacture’s instructions as previously described . We usedin vitro transcription reactions were performed with SP6 or T7 RNA polymerase in the presence of DIG-UTP by using a DIG RNA labeling Kit (Boehringer-Mannheim Biochemica). Labeling efficiency of the riboprobe was estimated by comparison with 10-fold serial dilution of a digoxigenin-labeled control riboprobe and direct detection of the labeled riboprobe with antidigoxigenin antibodies. Riboprobe concentrations were adjusted to be equivalent on the basis of the labeling efficiency before use in the in situ hybridization studies. The BP1 probe was used at a final concentration of 0.1–0.5 ng/μl in hybridization buffer. Subsequently the slides were washed and incubated with anti-digoxigenin antibody conjugated with alkaline phosphatase (Boehringer- Mannheim Biochemica) at the dilution of 1:750 for 30 min. at 37°C. The negative controls included: (1) hybridization with the sense probe, (2) RNase A  pretreatment before hybridization, and (3) omission of either the antisense RNA probe or the anti-digoxigenin antibody.In situ hybridization studies for FGF-BP were done in 4 μm sections as previously described . BrieflyBriefly, 96 wells plates  were coated with Histidine-tagged BP1 (0.1 ng/ml) diluted in Tris Buffered Saline. Excess of unbound His-BP was removed by washing. Non-specific binding was blocked by adding 300 μl (LB media) and further washes. [125]I-FGF-2 (1–20 μg/ml) was added to the wells at RT0 with constant rocking for two hours, and then, unbound FGF-2 was removed by washing. The binding of radiolabeled FGF-2 to His-BP1 was measured by counting radioactive emission from the individual wells. In some experiments we added HIV-Tat (1–3000 ng/ml) together with (1–20 μg/ml) FGF-2, to determine whether Tat can compete with FGF-2 for its binding to BP-FGF, or 1 hr later after addition of [125] I-FGF-2, to determine whether Tat can dissociate the complex FGF-2/BP1. To determine the specificity of Tat activity other experiments were done in the presence or absence of Nef and gp120 (1–3000 ng/ml). The HIV-1 recombinant peptides were provided by National Institute of Allergy and Infectious, Diseases, NIH AIDS Research and Reference Reagent Program: Tat (contributor Dr. John Brady); SIVnef (contributor Dr. Jose Torres); HIV-1IIIB gp120 . [125]-I-FGF2 was purchased from Amersham Pharmacia Biotech . Human recombinant FGF-2 was purchased from Life Technologies, Inc . Recombinant histidine-tagged BP1 protein purification was produced in Sf-9 insect cells with a baculovirus vector that contains an expression cassette for human BP1  as previously described (15–16). In addition, binding studies of [125]I-FGF-2 to its high and low affinity receptors were done in the presence or absence of BP1. These studies utilized recombinant FGFR-1/Fc chimera , containing the extracellular domain of human FGFR-1 fused via a polypeptide linker to the carboxy-terminal Fc region of human IgG1. The binding interactions between BP1 and HIV-Tat were evaluated by using saturation binding curves and by competitive displacement of the [125I] FGF–2 ligand with an excess of cold ligand (Tat or BP1).The generation of the tetracycline-regulated conditional BP1 transgenic mice, and the impact of BP1 on angiogenesis and wound healing, were previously described by Tassi et al. . BP1 traResults are expressed as the mean value + SD. Difference between two groups were compared by Students’t test. P-values less than 0.05 were considered significant. When more than two means were compared, difference was measured by one way analysis of variance followed by multiple comparisons using the Student-Neuman-Keul’s test.Since FGF-2 was detected in samples of both classic KS and AIDS-KS ,6 Figur and is cin vitro. Two other HIV-proteins, Nef and gp120 were also tested to determine the specificity of the Tat effects in this process. As shown in HIV-Tat protein, although initially described as a nuclear transcriptional regulatory protein, has also been shown to function as an angiogenic heparin-binding growth factor ,13. Morein vitro experiments to determine whether HIV-Tat may interfere with the binding of FGF-2 to FGFR1. In these experiments, [125]I-FGF2 was added to immobilized, recombinant FGFR1 protein in the absence or presence of Tat . As shown in Since HIV-Tat protein acts as an angiogenic growth factor and can bind FGF-2, we carried out additional A previous study by Tassi et al. showed that BP1 induced angiogenic lesions in the skin of BP1 ON conditional transgenic mice by 3-fold during wound healing . This efIn this study, we have described a potential novel mechanism by which the release and activity of FGF-2 can be modulated in AIDS-KS lesions. More specifically, we have found that a secreted FGF-binding protein (FGFBP1 or BP1) is produced by KS spindle cells, and by mononuclear cells infiltrating these vascular tumors. Since BP1 facilitates the release of FGF-2 from the extracellular matrix ,16,20, aIn general, the biological activity of FGF-2 is quenched by its tight binding to HSPG located in the extracellular matrix ,23. ThusOur data suggest an alternative mode of delivering active FGF-2 from the ECM storage site to its receptor could be via non-covalent binding to a secreted carrier protein. Such a secreted binding protein for FGFs was described by Sato and co-workers in 1991 . This prPrevious studies have shown that HIV-Tat synergizes with FGF-2 to induce the proliferation of endothelial and KS spindle cells. More recently we found that the heparin binding motif of HIV-Tat plays a crucial role facilitating its recruitment to lipid rafts and induction of FGF-2 signaling . Here, wThe protein coding sequence of the 234 amino acid FGFBP1 is contained in a single exon and the gene is located on chromosome 4 in human and the respective syntenic loci in other vertebrates . Other pIn summary, we have shown that a FGF binding protein (FGFBP1) which is known to positively modulate the angiogenic and growth promoting activity of FGF’s in tumor cells ,16, is e


The electrospun nanofibers giving rise to these porous-structured composite nanofibers with optimum amount of amorphous C are obtained from the polystyrene to polyacrylonitrile ratio of 1/4. These composite nanofibers also consist of uniformly distributed single-crystalline NiSe2 nanocrystals that have a mean size of 27 nm. In contrast, the densely structured bare NiSe2 nanofibers formed via selenization of the pure NiO nanofibers consist of large crystallites. The initial discharge capacities of the NiSe2-rGO-C composite and bare NiSe2 nanofibers at a current density of 200 mA g−1 are 717 and 755 mA h g−1, respectively. However, the respective 100th-cycle discharge capacities of the former and latter are 468 and 35 mA h g−1. Electrochemical impedance spectroscopy measurements reveal the structural stability of the composite nanofibers during repeated Na-ion insertion and extraction processes. The excellent Na-ion storage properties of these nanofibers are attributed to this structural stability.The first-ever study of nickel selenide materials as efficient anode materials for Na-ion rechargeable batteries is conducted using the electrospinning process. NiSe Next-generation rechargeable batteries have been extensively studied as a potential power source for large-scale devices such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and smart grids12356789111214et al. used a spray pyrolysis process to fabricate yolk-shell-structured MoSe2 microspheres as an anode material for NIBs; these microspheres delivered a 50th-cycle discharge capacity of 433 mA h g−1 at a current density of 0.2 A g−1 et al. used a simple hydrothermal method to fabricate nanooctahedra-assembled FeSe2 microspheres that delivered a stable discharge capacity of 372 mA h g−1 after 2000 cycles at 1 A g−1 −1 at a current density of 143 mA g−1 (~0.2 C) and stable cycle performance over 50 cycles2) materials have not been investigated as anode materials for NIBs.Recently, metal chalcogenide materials including metal sulfides and selenides have been successfully applied as anode materials for NIBs1617188202-reduced graphene oxide (rGO)-carbon composite porous nanofibers were prepared via an electrospinning and subsequent selenization process. Porous nanostructure could enhance the contact area between the host materials (NiSe2) and the electrolyte, additionally shorten the diffusion paths of the electrons and Na+ during cycling362 to alleviate pulverization during cycling362-reduced graphene oxide system to effectively alleviate the aggregation of NiSe2 nanoparticles by separating them from each other and helped reduced graphene oxide build more-efficient 3D conducting networks. The composite nanofibers composed of Ni salt, GO nanosheets, polystyrene (PS), and polyacrylonitrile (PAN) were transformed into the NiSe2-rGO-C composite nanofibers by using a simple selenization process.Electrospinning is a simple and highly versatile method used for the preparation of one-dimensional nanostructures of various compositions29303133342 nanoparticle-decorated rGO-C composite nanofibers is illustrated in x-Ni-rGO-C composite nanofibers were formed by post-treating the electrospun nanofibers formed from the colloidal DMF solution containing Ni acetate, PS, PAN, and GO nanosheets, at 450 °C under an Ar atmosphere. Subsequent selenization of these composite nanofibers at 300 °C under H2Se gas gives rise to the NiSe2-rGO-C composite nanofibers, in which NiSe2 nanocrystals are uniformly distributed throughout the rGO-C composite nanofibers.The formation mechanism of the NiSeThe effect of the PS on the morphologies of the electrospun nanofibers before and after the post-treatment is shown in 2-rGO-C composite nanofibers resulting from the selenization of the nanofibers shown in 2 nanocrystals are uniformly distributed over the surface of the composite nanofibers. These nanocrystals have a single-crystalline structure  analysis revealed that the composite nanofibers . The resulting XPS survey spectrum , epoxy and alkoxy groups (C–O), and carbonyl and carboxylic (C=O) components at 284.6, 286.6, and 288.1 eV, respectively; the peak corresponding to the C–C bond exhibits high intensity, whereas those associated with the C–O and C=O bonds have low intensities. This indicates that the GO nanosheets undergo thermal reduction to rGO nanosheets during the two-step post-treatment preparation process40tructure , as revenofibers  had a Ninofibers  show thaspectrum . The higspectrum  exhibitespectrum  occurredspectrum  also con2 nanofibers formed via selenization of the nanofibers shown in 2 nanofibers are cubic and phase-pure . The elemental mapping images also  and galvanostatic discharge/charge cycling at voltages ranging from 0.001–3 V vs. Na/Na+. −1 from the first five cycles of the NiSe2-rGO-C composite and bare NiSe2 nanofibers, respectively. The first cathodic scan of the NiSe2-rGO-C composite nanofibers exhibited two broad peaks at 1.2 and 0.9 V. However, the Na-ion insertion and desertion mechanisms of NiSe2 have not been identified in previous studies and therefore, the electrochemical reaction of NiSe2 for Na-ion storage was estimated from that of NiS2S + Nix and Na2Se, and Ni and Na2Se, respectively. During the anodic scans, two oxidation peaks, which may be attributed to the formation of NiSex and NiSe2, occurred at respective voltages of 1.8 and 1.9 V. A broad reduction peak  of the electrodes42Rct are calculated from a simulated equivalent circuit. Prior to cycling, the porous highly conductive NiSe2-rGO-C composite nanofibers had a lower Rct of 373 Ω -C composite nanofibers were prepared in a three-step process. During this process, nickel (II) acetate tetrahydrate-polyacrylonitrile-polystyrene with graphene oxide (GO) [Ni(OCOCH3)2·4H2O-PAN-PS-GO] composite nanofibers were prepared as precursor fibers via electrospinning. GO was synthesized from graphite flakes using a modified Hummers method, as described in our previous report3)2·4H2O , 1 g of PAN , 4 g of PS , and 0.2 g of GO into a solution of 50 mL of N,N-dimethylformamide . The prepared solution was loaded at a flow rate of 2 mL h−1 into a plastic syringe equipped with a 25-gauge stainless steel nozzle, ejected, and subsequently electrospun onto a drum collector covered with Al foil. During the electrospinning process, the drum rotated at 100 rpm and a distance of 20 cm was maintained between the tip and the collector; a voltage of 25 kV was applied between the collector and the syringe tip. The first step in the post-treatment process was performed at 450 °C for 3 h under an Ar atmosphere, and yielded NiOx-Ni nanosphere-decorated rGO-C composite nanofibers. In the second step of the process, these composite nanofibers were subjected to selenization at 300 °C for 10 h in H2Se gas, which was formed from commercial Se metal powders and H2 gas. For the selenization process, the composite nanofibers and Se metal powders were loaded into a covered alumina boat and placed in a quartz tube reactor; selenization resulted in the formation of NiSe2 nanosphere-decorated rGO-C composite nanofibers. Bare NiSe2 nanofibers were also synthesized for the sake of comparison. The nanofibers were prepared by electrospinning Ni(OCOCH3)2·4H2O-PAN composite nanofibers, without PS and GO, under conditions identical to the aforementioned conditions. Bare NiSe2 nanofibers were obtained by post-treating the resulting Ni(OCOCH3)2·4H2O-PAN composite nanofibers at 450 °C for 3 h under an air atmosphere and then selenizing at 300 °C for 10 h in H2Se gas.NiSeα radiation (λ = 1.5418 Å), performed at the Korea Basic Science Institute (Daegu), was used to evaluate the corresponding crystal structures. The composition of the specimens was determined via X-ray photoelectron spectroscopy  performed with a focused monochromatic Al Kα beam operating at 12 kV and 20 mA. Moreover, the surface area of the nanofibers was determined by using the Brunauer–Emmett–Teller (BET) method, with N2 as the adsorbate gas. The structure of the C in the specimens was characterized via Raman spectroscopy  performed at room temperature. Furthermore, thermogravimetric analysis (TGA) was performed using a Pyris 1 TGA (Perkin Elmer) at temperatures ranging from 25–650 °C at a heating rate of 10 °C min−1 under a static air atmosphere.The microstructure of the nanofibers was examined via field emission scanning electron microscopy  and field emission transmission electron microscopy . In addition, X-ray diffraction  using Cu K2 nanofibers were determined by constructing a 2032-type coin cell. The anode was prepared by mixing the active material, carbon black, and sodium carboxymethyl cellulose (CMC) in a weight ratio of 7:2:1. Na metal and microporous polypropylene film were used as the counter electrode and the separator, respectively. Moreover, the electrolyte used consisted of 1 M NaClO4 (Aldrich) dissolved in a mixture of ethylene carbonate/dimethyl carbonate , to which 5 wt% fluoroethylene carbonate (FEC) was added. The discharge/charge characteristics of the samples were investigated by cycling the cells at various current densities for potentials ranging from 0.001–3 V. The corresponding cyclic voltammograms (CV) were measured at a scan rate of 0.07 mV s−1. The dimensions of the negative electrode were 1.5 cm × 1.5 cm and the mass loading was approximately 1.2 mg cm−2. In addition, the electrochemical impedance over a frequency range of 0.01 Hz–100 kHz was measured via electrochemical impedance spectroscopy (EIS).The electrochemical properties of the fabricated NiSeHow to cite this article: Cho, J. S. et al. First Introduction of NiSe2 to Anode Material for Sodium-Ion Batteries: A Hybrid of Graphene-Wrapped NiSe2/C Porous Nanofiber. Sci. Rep. 6, 23338; doi: 10.1038/srep23338 (2016).