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Microvariant genotypes of Ostreid herpesvirus 1 (OsHV-1) are associated with mass mortality events of Pacific oysters in many countries. The OsHV-1 microvariant (µVar) emerged in France 2008 and caused significant economic losses as it became endemic and displaced the previously dominant OsHV-1 reference genotype. Recently, considerable genotypic variation has been described for OsHV-1 microvariants, however, less is known about variation in viral phenotype. This study used an in vivo laboratory infection model to assess differences in total cumulative mortality, peak viral load, transmissibility, and dose-response for three OsHV-1 isolates obtained between 2011 and 2015 from endemic waterways in Australia. This followed field observations of apparent reductions in the severity of mass mortalities over this time. Significantly higher hazard of death and cumulative mortality were observed for an isolate obtained in 2011 compared to isolates from 2014–2015. In keeping with other studies, the hazard of death was higher in oysters challenged by injection compared to challenge by cohabitation and the mortality was higher when the initial dose was 1 × 104 OsHV-1 DNA copies per oyster injection compared to 1 × 102 DNA copies. There was no difference in the quantity of OsHV-1 DNA at time of death that could be related to isolate or dose, suggesting similar pathogenetic processes in the individual oysters that succumbed to end-stage disease. While the isolates examined in this study were biased towards pathogenic types of OsHV-1, as they were collected during disease outbreaks, the variation in virulence that was observed, when combined with prior data on subclinical infections, suggests that surveillance for low virulence genotypes of OsHV-1 would be rewarding. This may lead to new approaches to disease management which utilize controlled exposure to attenuated strains of OsHV-1.  相似文献   
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Humans spend much of their lives engaging with their internal train of thoughts. Traditionally, research focused on whether or not these thoughts are related to ongoing tasks, and has identified reliable and distinct behavioral and neural correlates of task-unrelated and task-related thought. A recent theoretical framework highlighted a different aspect of thinking—how it dynamically moves between topics. However, the neural correlates of such thought dynamics are unknown. The current study aimed to determine the electrophysiological signatures of these dynamics by recording electroencephalogram (EEG) while participants performed an attention task and periodically answered thought-sampling questions about whether their thoughts were 1) task-unrelated, 2) freely moving, 3) deliberately constrained, and 4) automatically constrained. We examined three EEG measures across different time windows as a function of each thought type: stimulus-evoked P3 event-related potentials and non–stimulus-evoked alpha power and variability. Parietal P3 was larger for task-related relative to task-unrelated thoughts, whereas frontal P3 was increased for deliberately constrained compared with unconstrained thoughts. Frontal electrodes showed enhanced alpha power for freely moving thoughts relative to non-freely moving thoughts. Alpha-power variability was increased for task-unrelated, freely moving, and unconstrained thoughts. Our findings indicate distinct electrophysiological patterns associated with task-unrelated and dynamic thoughts, suggesting these neural measures capture the heterogeneity of our ongoing thoughts.

Cognitive neuroscience has reached a consensus that the brain is not idle at rest (1). This rings intuitively true: When left alone, our minds rarely stay still. Moreover, recent evidence suggests that rest is not a homogeneous state (2), nor is the brain truly “at rest” as it fluctuates across time and contexts (36). This too is intuitive: What is striking is not just that we move from thought to thought unprompted but also the diverse ways that trains of thought unfold over time. Sometimes, our thoughts freely wander between topics. You might remember this morning’s run, then imagine gardening, then think about the dinner you’ll cook tonight. Other times, we deliberately constrain our thoughts and work diligently toward a goal. In a quiet moment, you might methodically contemplate the results of your latest experiment. Still other times, our thoughts get stuck on an affectively salient topic, from which it is difficult to break free. You might worry, over and over, about your niece who is going through major surgery next week.Research has traditionally examined the internal train of thought in the context of mind wandering. This field has expanded at such a rapid pace that some have dubbed this the “era of the wandering mind” (7). To date, the vast majority of mind-wandering research has focused on the static content of individual thoughts. In particular, mind-wandering studies have primarily focused on task-unrelated thought (8)—that is, thoughts that are unrelated to an ongoing, typically externally oriented, task (810). In the laboratory, subjects’ thoughts are often unrelated to the experimental task (9). Task-unrelated thought is also frequent in everyday life (11), as when a student becomes distracted during a lecture or while driving.Recent theories are less task-centric and instead focus on the dynamics of mind wandering—that is, how internal trains of thoughts unfold over time (1217). In particular, the “dynamic framework” of spontaneous thought distinguishes three subtypes within the train of thoughts: 1) deliberately constrained, 2) automatically constrained, and 3) freely moving thoughts (12, 14). Constraints on the train of thoughts serve to focus internal attention on a topic for extended periods of time. For example, deliberately constrained thoughts occur when a person actively directs her thoughts to goal-relevant information (e.g., when you contemplate your latest experiment). This type of constraint is implemented through cognitive control. Automatically constrained thoughts focus on affectively or personally salient information that is difficult to disengage from (e.g., when you worry about your niece who will have surgery). This type of constraint is automatic in nature and thought to operate largely outside of cognitive control. In contrast, freely moving thoughts occur when both of these constraints are weak, allowing the mind to wander with no overarching purpose and direction (e.g., when your thoughts drift from a movie, to gardening, to dinner). Notably, the dynamic framework purports that these three subtypes of thoughts are independent of task relatedness. In other words, task-related and task-unrelated thoughts can both be deliberately constrained, automatically constrained, or freely moving. See SI Appendix for further details about the relationship between dynamic categories.Empirical research on the dynamics of thought is in its infancy. Behavioral research has focused on contrasting task-unrelated thoughts with the other three subtypes of thoughts, with a particular emphasis on freely moving thoughts. These findings suggest that self-reported freely moving and task-unrelated thoughts have distinct behavioral markers. For example, studies of mind wandering in everyday life found that self-reports of freely moving and task-unrelated thought fluctuate at different rates throughout the day (11). Consistent with predictions of the dynamic framework, these studies reported that task-unrelated and freely moving thoughts are only modestly correlated (r < 0.3) and they occurred independent of each other (8, 11). Specifically, although task-related thoughts are often deliberately constrained and task-unrelated thoughts sometimes move freely, the dynamic framework predicts that this is not always the case. In fact, task-related thoughts can move freely (e.g., when a graphic designer freely associate ideas for her new website design) or be automatically constrained (e.g., when someone obsesses over a problem at work). Task-unrelated thoughts can be deliberately or automatically constrained (e.g., when you construct a grocery list or worry about your niece’s surgery during a lecture). The only two empirical studies to date have focused explicitly on freely moving thought (8, 11). Although this provides some initial evidence that task-unrelated thought is different from dynamic thoughts, no studies have assessed the neural correlates of dynamic thought types. The identification of different electrophysiological signatures of these thought types would thus provide important validation that these categories reflect distinct entities.In the current study, we examined the electrophysiological signatures of the four types of thought by recording an electroencephalogram (EEG) while participants performed an attention task. Participants occasionally answered thought-sampling questions about the nature of their thoughts throughout the task. Thought sampling is the standard method in mind-wandering research: Participants are randomly interrupted as they perform a laboratory task and answer questions about their immediately preceding thoughts (9, 10). In line with previous studies, we ask the standard question about whether participants’ thoughts were task-unrelated (see ref. 8 for a review). In addition, we asked whether subjects’ trains of thought were freely moving, deliberately constrained, and automatically constrained.We used electroencephalography because this method has the temporal resolution necessary to capture the transient changes in neural activity corresponding to our trains of thoughts, including stimulus-evoked, task-dependent activity and stimulus-independent, intrinsic activity. We first examined event-related potentials (ERPs), which index the electrophysiological response evoked by task-relevant stimuli. Previous research suggests that task-unrelated thought attenuates the magnitude of ERP components associated with sensory (1820) and cognitive (2124) processing of task-relevant stimuli. ERPs therefore provide an electrophysiological signature of when a participant has disengaged from task-relevant stimuli. We predicted that task-unrelated thoughts would be associated with a reduced P3 ERP component.To index stimulus-independent, intrinsic neural activity, we examined spectral power in the alpha band (8 to 14 Hz) during a time window after the offset of ERPs, which is unlikely to be impacted by stimulus-evoked responses. This segregation of the poststimulus time window allowed us to disentangle stimulus-evoked, task-dependent responses captured by ERP components in the earlier window and stimulus-independent activity likely associated with the subject’s ongoing thoughts as captured by alpha power in the later time window (as illustrated in Fig. 1). Alpha-power increases recorded over posterior sites have been associated with internal attention (23, 25) as well as spontaneous brain activity recorded at rest that is not elicited by external stimuli (26, 27). In contrast, frontal alpha has been linked to creative, divergent thinking (28, 29). Accordingly, we hypothesized that task-unrelated thoughts would be associated with enhanced posterior alpha power, whereas freely moving thoughts would be associated with increased frontal alpha power. Given that our dynamic thought-sampling questions address variability within the train of thought over time, we examined the neural correlates of these thought dynamics by capturing momentary changes in alpha power (i.e., alpha-power variability) over the same ERP-free time window. We predicted that freely moving thought would be associated with increased alpha-power variability, whereas constrained thought would show reduced alpha-power variability.Open in a separate windowFig. 1.EEG measures across the poststimulus time window. We examined three EEG measures. Stimulus-evoked activity as captured by P3 ERP components was examined during the 0- to 0.6-s poststimulus time window. Alpha power and variability index intrinsic neural activity not impacted by an external stimulus examined after the offset of P3s during the 0.6- to 1.8-s poststimulus time window.  相似文献   
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Background

Over the last 10 years, the paradigm of damage control resuscitation (DCR) has been associated with improved patient outcomes. This study investigates the outcomes of both closed and open pelvic ring fractures at a single institution before and after the formal implementation of DCR principles.

Methods

A retrospective chart review was performed in an urban level I trauma center of all patients who sustained open or closed pelvic ring fractures between 2002 and 2012.

Results

Two thousand two hundred forty-seven patients presented with pelvic fractures between 2002 and 2012. Overall mortality was 10% (n = 212). Only 8% of all patients with closed fractures required DCR compared with 28% of patients with open fractures. There was no difference in mortality when comparing DCR and pre-DCR cohorts for either open or closed pelvic fractures.

Conclusions

Interestingly, although DCR seems to lead to more efficient initial resuscitations, further improvements in patient mortality were not realized with formal implementation of DCR principles.  相似文献   
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Background

Infection is a common phenomenon following stroke, and adversely affects outcome. Previous studies suggest that interleukin-1 receptor antagonist (IL-1ra) and single nucleotide polymorphisms (SNPs) in the IL1RN gene might influence the risk of post-stroke infection and outcome. In this study, we addressed the effects of the rs4251961 SNP in IL1RN on infection risk and outcome.

Methods

Subjects with acute ischemic stroke were enrolled within 72 h of symptom onset and followed up to 1 year. Plasma IL-1ra was measured at multiple time points and outcome assessed at 1, 3, 6, and 12 months. Active surveillance for infection occurred while subjects were hospitalized. Subjects were genotyped for the IL1RN rs4251961 polymorphism.

Results

In the population of 113 subjects for this study, those with the minor C allele of rs4251961 polymorphism in IL1RN were more likely to be Caucasian, hypertensive, and to be afflicted with coronary heart disease. Higher plasma IL-1ra was associated with an increased risk of infection (other than pneumonia), and the minor C allele of rs4251961 was independently associated with a decreased risk of infection (other than pneumonia). Initial plasma IL-1ra was not predictive of long-term outcome, but patients with the minor C allele of rs4251961 were more likely to experience good (modified Rankin Score <2) long-term outcome.

Conclusions

These data indicate that IL-1ra and IL1RN may influence the risk of infection after stroke, but this influence seems limited to infections other than pneumonia. Further studies are needed to better understand the complexities of immune regulation on infection and outcome after stroke.  相似文献   
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