Evaluating instrumental learning and striatal-cortical functional connectivity in adolescent alcohol and cannabis use

Adolescence is a vulnerable time for the acquisition of substance use disorders, potentially relating to ongoing development of neural circuits supporting instrumental learning. Striatal-cortical circuits undergo dynamic changes during instrumental learning and are implicated in contemporary addiction theory. Human studies have not yet investigated these dynamic changes in relation to adolescent substance use. Here, functional magnetic resonance imaging was used while 135 adolescents without (AUD-CUDLow ) and with significant alcohol (AUDHigh ) or cannabis use disorder symptoms (CUDHigh ) performed an instrumental learning task. We assessed how cumulative experience with instrumental cues altered cue selection preferences and functional connectivity strength between reward-sensitive striatal and cortical regions. Adolescents in AUDHigh and CUDHigh groups were slower in learning to select optimal instrumental cues relative to AUD-CUDLow adolescents. The relatively fast learning observed for AUD-CUDLow adolescents coincided with stronger functional connectivity between striatal and frontoparietal regions during early relative to later periods of task experience, whereas the slower learning for the CUDHigh group coincided with the opposite pattern. The AUDHigh group not only exhibited slower learning but also produced more instrumental choice errors relative to AUD-CUDLow adolescents. For the AUDHigh group, Bayesian analyses evidenced moderate support for no experience-related changes in striatal-frontoparietal connectivity strength during the task. Findings suggest that adolescent cannabis use is related to slowed instrumental learning and delays in peak functional connectivity strength between the striatal-frontoparietal regions that support this learning, whereas adolescent alcohol use may be more closely linked to broader impairments in instrumental learning and a general depression of the neural circuits supporting it.

Brain function and clinical characterization in the Boston adolescent neuroimaging of depression and anxiety study

We present a Human Connectome Project study tailored toward adolescent anxiety and depression. This study is one of the first studies of the Connectomes Related to Human Diseases initiative and is collecting structural, functional, and diffusion-weighted brain imaging data from up to 225 adolescents (ages 14-17 years), 150 of whom are expected to have a current diagnosis of an anxiety and/or depressive disorder. Comprehensive clinical and neuropsychological evaluations and longitudinal clinical data are also being collected. This article provides an overview of task functional magnetic resonance imaging (fMRI) protocols and preliminary findings (N = 140), as well as clinical and neuropsychological characterization of adolescents. Data collection is ongoing for an additional 85 adolescents, most of whom are expected to have a diagnosis of an anxiety and/or depressive disorder. Data from the first 140 adolescents are projected for public release through the National Institutes of Health Data Archive (NDA) with the timing of this manuscript. All other data will be made publicly-available through the NDA at regularly scheduled intervals. This article is intended to serve as an introduction to this project as well as a reference for those seeking to clinical, neurocognitive, and task fMRI data from this public resource.

First Accurate Normalization of the β-delayed α Decay of ^{16}N and Implications for the ^{12}C(α,γ)^{16}O Astrophysical Reaction Rate

The ^{12}C(α,γ)^{16}O reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced α width, γ_{11}, of the bound 1^{-} level in ^{16}O is particularly important to determine the cross section. The magnitude of γ_{11} is determined via sub-Coulomb α-transfer reactions or the β-delayed α decay of ^{16}N, but the latter approach is presently hampered by the lack of sufficiently precise data on the β-decay branching ratios. Here we report improved branching ratios for the bound 1^{-} level [b_{β,11}=(5.02±0.10)×10^{-2}] and for β-delayed α emission [b_{βα}=(1.59±0.06)×10^{-5}]. Our value for b_{βα} is 33% larger than previously held, leading to a substantial increase in γ_{11}. Our revised value for γ_{11} is in good agreement with the value obtained in α-transfer studies and the weighted average of the two gives a robust and precise determination of γ_{11}, which provides significantly improved constraints on the ^{12}C(α,γ) cross section in the energy range relevant to hydrostatic He burning.

Study of key resonances in the 30P(p,γ)31S reaction in classical novae

Among reactions with strong impact on classical novae model predictions, 30P(p,γ)31S is one of the few remained that are worthy to be measured accurately, because of their rate uncertainty, as like as 18F(p,α)15O and 25Al(pγ)26Si. To reduce the nuclear uncertainties associated to this reaction, we performed an experiment at ALTO facility of Orsay using the 31P(3He,t)31S reaction to populate 31S excited states of astrophysical interest and detect in coincidence the protons coming from the decay of the populated states in order to extract the proton branching ratios. After a presentation of the astrophysical context of this work, the current situation of the 30P(p,γ)31S reaction rate will be discussed. Then the experiment set-up of this work and the analysis of the single events will be presented.

Behavior of Natural Uranium, Thorium and Radium Isotopes in The Wolfcamp Brine Aquifers, Palo Duro Basin, Texas

Previously reported results for Palo Duro deep brines show that Ra is highly soluble and not retarded. Relative to Ra, U and Th are highly sorbed. Uranium, like thorium, is in the +4 valence state, indicating a reducing environment. Additional data reported here support these results. However, one Wolfcamp brine sample gives somewhat different results. Radium appears to be somewhat sorbed. Uranium is largely in the +6 valence state, indicating a less reducing condition. In all brines, kinetics for sorption (228Th) and desorption (224Ra) are rapid. This Wolfcamp brine was tested for the effects of colloids for Ra, U, and Th concentrations. No effects were found.

The Use of Natural Radionuclides to Predict the Behavior of Radwaste Radionuclides In Far-Field Aquifers

In appropriate aquifers the natural radionuclides of the U and Th decay series are important sources of information about the behavior of radwaste radionuclides in far-field aquifers. The Wolfcamp Carbonate, Pennsylvanian Carbonate and Granite Wash aquifers in the Palo Duro Basin of the Texas Panhandle are prime examples of such aquifers. Sampling and analysis for key radionuclides in the ground waters of these aquifers are quite feasible and have been accomplished. Key early results are: (1) Ra does not appear to be retarded by sorption, (2) Th appears to be strongly sorbed, (3) kinetics seem to be different on time scales of days to months than on ones of hundreds of thousands of years, and (4) U and Th behave similarily when the time scales (half-lives) are similar, leading to the suggestion that uranium is in the +4 valence state in these aquifers.

Endoscopic endoluminal radiofrequency ablation of Barrett's esophagus in patients with fundoplications

BACKGROUND

Endoscopic endoluminal radiofrequency ablation using the Barrx device is a new technique to treat Barrett's esophagus. This procedure has been used in patients who have not had antireflux surgery. This report is presents an early experience of the effects of endoluminal ablation on the reflux symptoms and completeness of ablation in post-fundoplication patients.

METHODS

Seven patients who have had either a laparoscopic or open Nissen fundoplication and Barrett's esophagus underwent endoscopic endoluminal ablation of the Barrett's metaplasia using the Barrx device (Barrx Medical, Sunnyvale, CA). Preprocedure, none of the patients had significant symptoms related to gastroesophageal reflux disease. One to two weeks after the ablation, patients were questioned as to the presence of symptoms. Preprocedure and postprocedure, they completed the GERD-HRQL symptom severity questionnaire (best possible score, 0; worst possible score, 50). Patients had follow-up endoscopy to assess completeness of ablation 3 months after the original treatment.

RESULTS

All patients completed the ablation without complications. No patients reported recurrence of their GERD symptoms. The median preprocedure total GERD-HRQL score was 2, compared to a median postprocedure score of 1. One patient had residual Barrett's metaplasia at 3 months follow-up, requiring re-ablation.

CONCLUSIONS

This preliminary report of a small number of patients demonstrates that endoscopic endoluminal ablation of Barrett's metaplasia using the Barrx device is safe and effective in patients who have already undergone antireflux surgery. There appears to be no disruption in the fundoplication or recurrence of GERD-related symptoms. Nevertheless, longer-term follow-up with more patients is needed.

The nature of thrombosis induced by platinum and tungsten coils in saccular aneurysms

PURPOSE

To compare the efficacy and biocompatability of electrolytic and mechanically detachable embolization coils of two metal types.

METHODS

Experimental saccular aneurysms in pigs were used to assess embolization induced by platinum or tungsten coils. Longitudinal angiographic and histologic studies were performed on treated and untreated (control) aneurysms to compare thrombosis and cellular responses after embolization with electrolytically detachable platinum coils and with mechanically detached tungsten coils.

RESULTS

Fewer tungsten than platinum coils were needed to induce thrombosis. The inflammatory response within the aneurysmal lumen was more florid in embolized aneurysms than in control aneurysms. No difference was found in the timing or extent of accumulation of eosinophils, lymphocytes, or polymorphs between the two coils used. Giant cell responses were more marked in treated aneurysms; tungsten coils more than platinum coils. The amount of collagen and fibrosis present increased over the study period and was similar in treated and control aneurysms.

CONCLUSION

The coil type influenced the initial cellular response but had little effect on the rate or degree to which blood clot within the aneurysm was replaced by fibrous tissue.

Endovascular coil occlusion of experimental aneurysms: partial treatment does not prevent subsequent rupture

Experimental aneurysms with a high propensity to spontaneous rupture were used to assess the efficacy of endosaccular packing with platinum coils. Lateral aneurysms, surgically constructed in pigs from vein allographs, were untreated or treated by partial or total endovascular packing with coils. All untreated aneurysms (4/4) ruptured and most (3/4) partially treated aneurysms also ruptured. None of 6 aneurysms in which the lumen was occluded by 90% or more ruptured or demonstrated regrowth on subsequent angiography. Partial treatment was therefore not effective in preventing delayed haemorrhage. These findings suggest that subtotal endovascular treatment may not be protective after aneurysmal subarachnoid haemorrhage.