Scalable one-step production of electrochemically exfoliated graphene decorated with transition metal oxides for high-performance supercapacitors.

Graphene and related materials have been widely studied due to their superior properties in a wide range of applications. However, large-scale production remains a critical challenge to enable commercial acceptance. Here, we present a facile, scalable, one-step electrochemical method for producing hybrid transition metal oxide (V, Fe, Ti, or Mn)/graphene materials (TMO-EGs) as active materials for supercapacitors. Therein, we have designed and developed a continuous flow reactor with a high production rate (>4 g h-1) of TMO-EGs, where the TMO accounts for 36 weight%. TMO-EG flakes demonstrate a moderate lateral size of up to 5 µm and a specific surface area of 64 m2 g-1. Notably, TMO-EGs present a capacitance of up to 188 F g-1 as single electrodes in 4 M LiCl. The most promising material, MnOx-EG, has been used for the large-scale production of thin-film supercapacitor devices (40 × 40 × 0.25 mm) in a commercial pilot line. Using 1 M Na2SO4 as the electrolyte, the as-fabricated devices deliver a capacitance of 52 mF cm-2, with 83% capacitance retention after 6000 charge-discharge cycles, comparable to recent reports of similar devices. The simplicity, scalability, and versatility of our method are highly promising to promote the commercial applications of graphene-based materials and can be further developed for the upscalable production of other 2D materials, such as transition metal dichalcogenides and MXenes.

Do alcohol-dependent patients show different neural activation during response inhibition than healthy controls in an alcohol-related fMRI go/no-go-task?

RATIONALE: Alcohol dependence is associated with impaired response inhibition and heightened cue reactivity towards alcohol-related stimuli. Several brain areas, but mainly prefrontal structures, have been linked to response inhibition in addiction. This study aimed at combining both aspects: salience of drug-associated cues and response inhibition using a go/no-go task with alcohol-associated stimuli during functional magnetic resonance imaging (fMRI). OBJECTIVES: Nineteen abstinent alcohol-dependent patients (ADP) and 21 healthy control subjects (HC) were compared on blood oxygen level-dependent (BOLD) responses during successful inhibition of no-go stimuli and successful reactions to go stimuli. RESULTS: ADP and HC did not significantly differ in their behavioural performance in the task. However, both groups performed worse during the inhibition of alcoholic-associated stimuli compared to neutral stimuli. On the neural level, ADP displayed enhanced BOLD activity relative to HC during successful response inhibition in several areas involved in visual processing, cognitive and impulse control, including occipital structures, anterior cingulate gyrus, medial frontal gyrus and medial orbitofrontal cortex. CONCLUSIONS: We interpret these findings as a possible compensation strategy for impaired cognitive processing. Furthermore, the results underline the impact of salience of alcohol-related stimuli on response inhibition, which seems to affect both ADP and HC.

The impact of cognitive impairment and impulsivity on relapse of alcohol-dependent patients: implications for psychotherapeutic treatment.

Recent models of the development of addiction propose a transition from a pleasure-driven to a heavily automatized behaviour, marked by a loss of cognitive control. This study investigated the deficits in different components of cognitive functions including behavioural inhibition in response to alcohol-related stimuli in alcohol-dependent patients (ADP) and healthy controls (HC). The aims of the study were to identify which particular cognitive functions are impaired in ADP. Furthermore, we analysed the association between cognitive deficits and relapse rates and the reversibility of cognitive deficits under abstinence in a 6-month follow-up period. Ninety-four recently detoxified ADP and 71 HC completed the cognitive tasks as well as questionnaire measures assessing drinking behaviour and personality traits. Compared with HC, ADP showed poorer performance in response initiation, response inhibition, complex-sustained attention and executive functions. Impairment in response inhibition was a significant predictor for relapse, yet the strongest predictor was the interaction between the number of previous detoxifications and response-inhibition deficits. The results of a moderation analysis showed that patients with many previous detoxifications and large deficits in response inhibition showed the highest relapse risk. These findings indicate that interventions should take into account inhibitory deficits especially in ADP with a high number of previous detoxifications.

Stability of phosphatidylethanol species in spiked and authentic whole blood and matching dried blood spots.

BACKGROUND: Phosphatidylethanol (PEth) is currently under investigation as a highly sensitive and specific marker of alcohol misuse. As its stability in blood samples has not systematically been investigated, a study was performed to determine the stability of major PEth species in spiked and authentic whole blood and also in matching dried blood spots (DBS) at different conditions. METHODS: To PEth-free blood from teetotalers, low and high concentrations of two major PEth (18:1/18:1 and 16:0/18:1) species were added chosen on the basis of concentrations determined from authentic samples which were collected from the subjects undergoing alcohol detoxification treatment. Effects of sampling (EDTA or heparinized tubes), temperature, and time (≤30 days) were investigated. Processed samples (two at each condition, respectively) were subjected to LC gradient separation using multiple reaction monitoring. Stability was assessed using the critical difference or a periodic analysis result that was within 15 % of the initial concentration. Reaction kinetics of degradation was investigated with rate constants being checked for an Arrhenius relationship. RESULTS: PEth was stable in dried blood spot (DBS) stored either at room temperature or frozen, whereas it was not stable in whole blood except in samples stored at -80 °C. Activation energies increased in the following order: spiked heparinized blood < spiked EDTA blood < authentic EDTA blood. CONCLUSIONS: PEth is a labile analyte which is predominantly degraded by hydrolysis. Only at -80 °C, stability in whole blood can be ascertained, and analysis should be performed within 30 days. EDTA should be preferred over heparin as an additive. DBS is able to stabilize PEth thus partly resolving pre-analytical difficulties of PEth measurement.

LC-MS/MS analysis of phosphatidylethanol in dried blood spots versus conventional blood specimens.

Phosphatidylethanol (PEth), which is formed extrahepatically by the action of phospholipase D on phosphatidylcholine in the presence of ethanol, has been suggested as a promising marker of alcohol misuse. Analysis of dried blood spots (DBS) is particularly advantageous for the determination of delicate analytes such as PEth. Therefore, measurement of PEth species (18:1/18:1, 16:0/18:1) in DBS versus whole blood was performed to ascertain whether respective results are directly comparable. Samples were obtained from subjects (n = 40) undergoing alcohol detoxification treatment. Analysis involved liquid-liquid extraction from both, DBS and whole blood (100 µL, respectively), with phosphatidylpropanol as the internal standard. Extracts were subjected to LC gradient separation using multiple reaction monitoring of deprotonated molecules. Results from measurements of corresponding DBS and whole blood specimens were compared by estimating the respective mean values and by a Bland and Altman analysis. Concentrations of PEth 18:1/18:1 ranged from 46.1 to 3,360 ng/mL in whole blood (mean, 461.7 ng/mL) and from 35.8 to 3,360 ng/mL in DBS (mean, 457.6 ng/mL); for PEth 16:0/18:1, concentrations were from 900 to 213,000 ng/mL (mean, 23,375 ng/mL) and 922-213,000 ng/mL (mean, 23,470 ng/mL) in blood and DBS, respectively. Estimated mean differences were -4.3 ng/mL for PEth 18:1/18:1 and 95.8 ng/mL for PEth 16:0/18:1. The Bland-Altman plot of both PEth species showed that the variation around the mean difference was similar all through the range of measured values and that all differences except one were within the limits of agreement. It could be shown that the determination of PEth species in DBS is as reliable as in whole blood samples. This assay may facilitate monitoring of alcohol misuse.