The effects of psychological stress on approach tendencies for smoking-related cues in smokers.

Stress may potentiate the chronification of nicotine addiction, but the exact mechanisms remain elusive. We performed an explorative pilot study examining the effects of psychological stress, administered via the socially evaluated cold pressor task (SECPT), on implicit approach bias for smoking-related cues in smokers in the approach-avoidance task (AAT). Smokers (N = 24) were subjected to the stress or control condition of the SECPT by using a within-subject design. Consistent with previous findings, a strong approach bias for smoking-related cues in the AAT was found in smokers. Exposure to stress did not affect the general bias for smoking-related cues in the AAT relative to the control condition of the SECPT. In additional explorative analyses, an interaction among carbon monoxide (CO) levels in expired air, cortisol levels, and stress on approach bias for smoking-related cues was found. Higher CO levels, possibly due to recent smoking, prior to stress exposure were associated with an approach bias for smoking-related cues. Our results suggest that CO levels in interaction with stress can modulate implicit, automatic processing in the context of nicotine addiction. Our findings might provide novel cues to how stress influences cigarette craving and smoking behavior.

The relationship of action, affect, and metacognition in functional seizures.

INTRODUCTION: Metacognition provides a lens through which individuals experience, interpret, and respond to their affective states and behavior; it might thus influence complex neuropsychiatric conditions such as functional seizures - events characterized by states of heightened affective arousal and the disinhibition of prepotent behavior. In this pilot study, we aimed to establish a better understanding of the role of metacognition in functional seizures and its relationship to affective arousal and behavioral disinhibition (i.e., problems in suppressing prepared behavior). We hypothesized that affective arousal is related to higher behavioral disinhibition as well as slower reaction times, that affect and action (performing vs. not performing a movement) are related to memory and metacognition, and that metacognition is related to illness characteristics. METHODS: We used a combination of an emotional go/no-go and a metacognitive recognition task with affectively valenced and neutral images in 18 patients with functional seizures. We compared markers of behavioral inhibition as well as indices for memory and metacognitive performance between affective (vs. neutral) and action/go (vs. inhibition/no-go) conditions. RESULTS: Contrary to our hypothesis, behavioral disinhibition was not different between conditions. However, we found slower reaction times for affectively valenced stimuli. Memory performance and metacognition were better for affectively valenced pictures and for pictures used in go trials (i.e., associated with action/performing the movement). Illness factors (illness duration, seizure frequency, levels of self-reported anxiety) were correlated with aspects of metacognition. CONCLUSIONS: This pilot study offers first insights into alterations in metacognition related to action and affect in patients with functional seizures; specifically, that affectively valenced stimuli and active engagement are related to enhanced memory and metacognition. This relationship was also found with respect to illness factors. These results provide insight into potentially underlying pathomechanisms, although the lack of a control group limits evaluating the specificity of these findings.

Activation and fluoride-assisted phosphating of aluminum-silicon-coated steel.

Phosphating is a crucial process in the corrosion protection of metals. Here, activation and fluoride-assisted tricationic phosphating is investigated on aluminum-silicon (AS) coated steel surfaces. Dynamic light scattering results from the activation bath show a bimodal size distribution, with hydrodynamic radii of ~400 nm and ~10 µm. For the smaller particle fraction, static light scattering results are consistent with the interpretation of disklike particles as scattering objects. Particles of the larger fraction sediment with time. In the presence of electrolyte, the scattering intensity from the larger particle fraction increases. Coagulation with time is suggested to be related to the decrease in activity of the activation bath. Scanning Auger microscopy (SAM) shows a higher phosphorus concentration after titanium phosphate activation in the Al-rich areas compared to the Si-rich areas of the AS coatings. There is no correlation between the size of the species in the activation bath, and the size of the phosphate-containing regions on the activated surface. Phosphating was performed in the presence of hexafluorosilicic acid, H2SiF6, ammonium hydrogen difluoride, NH4HF2, and both, at an initial pH of 2.5. The absence of crystals after phosphating with H2SiF6 is an indication that SiF6(2-) is the final product of the oxide dissolution in the presence of fluoride. In the presence of NH4HF2, the Si-rich regions of the surface are phosphated before the Si-poor (Al-rich) regions. Hence, the phosphate distribution after activation and after phosphating are opposite. These results show that a high surface concentration of phosphate after activation is not sufficient for a high coverage with phosphate crystals after phosphating.