The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei

The physical conditions in a high density hydrogen gas heated and ionized by suprathermal protons were investigated, with application to the gas in the nuclear region of Seyfert galaxies. The gas is assumed optically thick to Lyman and Balmer line radiation. Mechanisms by which the radiation from the gas can balance the heating by the fast protons were investigated, and minimum values for the mass of gas were estimated. Under certain conditions, the suprathermal atoms themselves can cool the ambient gas by rescattering the line radiation into the optically thin region in the wings of the line. This mechanism, called optical reverberation, can enhance the broad component of the hydrogen lines produced by inelastic atomic collisions and yield line widths consistent with those observed in Seyfert and quasar spectra. Also discussed is the possibility of achieving dynamic equilibrium of the ambient gas by balancing the momentum transfer from the suprathermals with gravitational attraction of a massive central source

On the interpretation of FE 2 emission profiles in Seyfert galaxies and QSOs

High-resolution spectral scans of several QSOs and Seyfert galaxies show broad Balmer lines and permitted Fe II lines in emission. It is suggested that a careful comparison of the Fe II and Balmer profiles may distinguish between the different proposed mechanisms for broadening of the lines. In particular, if the Fe II profile is much narrower that the hydrogen profile, the suprathermal particle mechanism is most likely presented

Penetration of the insect defensin A into phospholipid monolayers and formation of defensin A-lipid complexes

Defensin A is an inducible cationic protein secreted in the hemolymph of fleshfly Phormia terranovae larvae in response to bacterial or septic injuries. Defensin A is known to permeabilize the bacteria cell membranes by forming voltage-dependent channels. The penetration of this small protein into lipid monolayers was studied as a function of the polar head and acyl chain length of phospholipids. The extent of penetration by defensin A is higher in monolayers made of anionic phospholipids than in monolayers made of zwitterionic phospholipids (phosphatidylcholines), because of electrostatic interactions. From the analysis of the compression isotherm parameters of mixed defensin A/phospholipid monolayers, it appears that defensin A interacts with phospholipid by forming 1:4 complexes. These complexes are not miscible in the lipid phase and induce microheterogeneity in the lipid membrane. These clusters might be related to the ion-channel structures responsible for the biological activity of defensin A

The Relationship of Hard X-ray and Optical Line Emission in Low Redshift Active Galactic Nuclei

In this paper we assess the relationship of the population of Active Galactic Nuclei (AGN) selected by hard X-rays to the traditional population of AGN with strong optical emission lines. First, we study the emission-line properties of a new hard X-ray selected sample of 47 local AGN (classified optically as both Type 1 and Type 2 AGN). We find that the hard X- ray (3-20 keV) and [OIII]$\lambda$5007 optical emission-line luminosities are well-correlated over a range of about four orders-of-magnitude in luminosity (mean luminosity ratio 2.15 dex with a standard deviation of $\sigma$ = 0.51 dex). Second, we study the hard X-ray properties of a sample of 55 local AGN selected from the literature on the basis of the flux in the [OIII] line. The correlation between the hard X-ray (2-10 keV) and [OIII] luminosity for the Type 1 AGN is consistent with what is seen in the hard X-ray selected sample. However, the Type 2 AGN have a much larger range in the luminosity ratio, and many are very weak in hard X-rays (as expected for heavily absorbed AGN). We then compare the hard X-ray (3-20 keV) and [OIII] luminosity functions of AGN in the local universe. These have similar faint-end slopes with a luminosity ratio of 1.60 dex (0.55 dex smaller than the mean value for individual hard X-ray selected AGN). We conclude that at low redshift, selection by narrow optical emission- lines will recover most AGN selected by hard X-rays (with the exception of BL Lac objects). However, selection by hard X-rays misses a significant fraction of the local AGN population with strong emission lines

Emotion regulation after traumatic brain injury: distinct patterns of sympathetic activity during anger expression and recognition

Abstract OBJECTIVE: To assess psychological and psychophysiological correlates of emotion recognition and anger experience in participants with traumatic brain injury (TBI). PARTICIPANTS: Twenty participants with TBI presenting with anger problems and 22 healthy controls. PROCEDURES: Participants were administered tasks assessing emotion recognition (The French Evaluation Task) and anger expression (Anger regulation task). The latter, designed to elicit and modulate anger feelings through verbal recall of a self-experienced event, involved 4 recall conditions that followed a resting period: neutral, uninstructed anger recall, anger rumination, and anger reappraisal. MEASURES: Skin conductance levels during recall and a self-report anger questionnaire between each condition. RESULTS: In the TBI and control groups, self-reported anger was similarly modulated across emotion regulation conditions. However, only in the TBI group did skin conductance levels significantly increase between neutral and uninstructed anger recall conditions. CONCLUSIONS: Impaired emotion regulation in TBI participants could be related to increased levels of autonomic system activity during emotional experience. However, anger feelings in these participants can also be modulated with the use of emotion regulation strategies, including adaptive strategies such as reappraisal. Thus, promoting awareness and management of physiological activation and encouraging cognitive restructuring can be recommended as a component of interventions targeting emotion regulation in TBI patients

Chronic toxic encephalopathy in a painter exposed to mixed solvents.

This paper describes symptoms and findings in a 57-year-old painter who had been exposed to various organic solvents for over 30 years. He began to work as a painter at 16 years of age, frequently working in poorly ventilated areas; he used solvents to remove paint from the skin of his arms and hands at the end of each work shift. The patient and his family noticed impaired short-term memory function and changes in affect in his early forties, which progressed until after he stopped working and was thus no longer exposed to paints and solvents. After the patient's exposures had ended, serial neuropsychological testing revealed persistent cognitive deficits without evidence of further progression, and improvement in some domains. Magnetic resonance imaging revealed global and symmetrical volume loss, involving more white than gray matter. The findings in this patient are consistent with chronic toxic encephalopathy and are differentiated from other dementing processes such as Alzheimer's disease, multi-infarct (vascular) dementia, and alcoholic dementia. Previous descriptions in the literature of persistent neurobehavioral effects associated with chronic exposure to organic solvents corroborate the findings in this case