Unexpected and delayed fragmentation dynamics of the organometallic ferrocene induced by ion-collision.

We have investigated the fragmentation dynamics of the organometallic ferrocene molecule after interaction with multiply charged ions using multicoincidence mass spectrometry and quantum chemistry calculations. We observed unexpected fragmentation dynamics of the two-body breakup channels from ferrocene dications revealing a charge screening effect from the iron atom and delayed fragmentation dynamics. These observations are rationalized through the population of a specific long-lived excited state, where one positive charge is located on each cyclopentadienyl ring.

Treatment of skin lesions related to pseudoxanthoma elasticum in plastic surgery.

BACKGROUND: Pseudoxanthoma elasticum (PXE) is a hereditary disorder of connective tissue characterized by progressive calcification and fragmentation of elastic fibers, which primarily affects the skin, retinal and arterial walls. Skin damage takes the form of yellow papules that can merge to create a cutaneous fold. This is accompanied by an excess of skin on the different sides of the neck and in the largest folds. These changes to the skin have a significant aesthetic, functional and psychological impact, especially among women. PATIENTS AND METHODS: We evaluated the treatment options in all patients with PXE of our University-Hospital. This group contains people who have been hospitalized for the assessment of their disease and applicants for surgical correction. The goal of the surgery was not the total removal of the lesions but instead a decrease in their size and a tightening of the skin. RESULTS: In total, 250 patients were seen between 2007 and 2022. Surgical treatment was advised for 29 women and 1 man. The main interventions were based on standard techniques such as cervico-facial facelifts, brachioplasties and cruroplasties. The results obtained during postoperative follow-up consultations were rated satisfactory to very good, both aesthetically and functionally. There were no postoperative complications recorded: neither bruising nor scarring issues. Patients with PXE heal as normal. CONCLUSION: Surgical treatment for excess skin observed during PXE is poorly described. Yet, these excesses can be removed when they become troublesome by making use of and adapting the traditional methods of plastic surgery for tightening of the skin.

[Nasal reconstruction: Decision tree based on 229 operated cases]. / Reconstruction des pertes de substances du nez : algorithme décisionnel à propos de 229 cas.

BACKGROUND: The Face is the most frequent localization for cutaneous carcinoma. The nose accounts for about 30% of these tumors. Nose tissue loss repair has to pursue 3 types of objectives: carcinologic, aesthetic and functional. The aim of this article is to identify a decision tree to guide the choice of surgical reconstruction technique based on localization and size of the defect. PATIENTS AND METHODS: We performed a retrospective analysis in Angers' CHU from 2013 to 2019 including 229 patients referred for cutaneous tumors excision in need of reconstruction. We analyzed the type of reconstruction, size of the tissue loss and localization of the defect in terms of nose aesthetic subunits. RESULTS: Among the 229 patients included, the most frequent localization was nose tip (32%). 44% of patients were reconstructed with skin grafts or composite graft, 56% with flaps (48% local flaps and 4% association of both methods). Limited central resections of nose tip were reconstructed with skingraft. The Rybka flap and bilobed flap were the preferred choice for lateral reconstruction of nose tip. Largest tip defects were reconstructed using Rieger flap or forehead flap. The dorsum was often reconstructed with local flap: glabellar on the upper part, Rieger on the lower part. Lateral side was perfectly reconstructed with island flap. Nose wings needed framework: composite graft was the judicious choice in case of limited tissue loss whereas forehead flap with framework or Schmid-Meyer flap were chosen for larger defects. CONCLUSION: Our past experience in nasal reconstruction has provided us with an original decision tree to guide surgeons in choosing the right reconstruction technique according to the size and localization of the defect.

Increase of precuneus metabolism correlates with reduction of PTSD symptoms after EMDR therapy in military veterans: an 18F-FDG PET study during virtual reality exposure to war.

PURPOSE: The prevalence of posttraumatic stress disorder (PTSD) is higher among veterans, and can lead to disastrous consequences such as suicide. Eye movement desensitization and reprocessing (EMDR) is recommended in first-line psychotherapies for PTSD. Virtual reality exposure (VRE) coupled with 18F-FDG PET imaging can highlight the activated brain regions during stress exposure. The objective of this study is to identify, after EMDR therapy, the regions of brain metabolism that evolve during the stress exposure of a war scene with symptomatic remission in a group of military veterans suffering from PTSD, and to secondarily search for predictive metabolic features. METHODS: We recruited 15 military veterans suffering from PTSD who performed an 18F-FDG PET sensitized by the exposure to a virtual war scene, before (T0) and after (T1) EMDR therapy. Statistical parametric mapping was used to compare brain metabolism before and after treatment and to study correlations between metabolism and evolution scores on PTSD clinical scales (PTSD Checklist Scale, PCLS; Clinician-Administered PTSD Scale, CAPS). RESULTS: The metabolic activity of the precuneus was increased after EMDR therapy (p < 0.005 uncorrected, k > 180) and correlated with clinical improvement with the CAPS scale (r = -0.73 and p < 0.001). Moreover, the precuneus metabolic value before therapy predicted the clinical improvement on the PCLS scale (T1-T0) after EMDR (r = -0.667 and p < 0.006). CONCLUSION: The clinical improvement in military patients with PTSD after EMDR is related to increased precuneus metabolism upon VR stress exposure.

Multiple electron capture from isolated protein poly-anions in collision with slow highly charged ions.

Collisions of 375 keV Xe25+ ions with trapped mass/charge selected poly-anions of the cytochrome C protein (∼12.5 kDa) were studied by coupling a linear quadrupole ion trap with low-energy ion beam facility. Tandem mass spectra were recorded for the protein precursor charge states ranging from -9 to -17. The present work reports the first study of slow highly charged ion collisions with poly-anions. A high signal to noise ratio allowed the study of the intensity of single and multiple electron removal by a projectile, as well as associated neutral losses, as a function of the target charge state. Relative single and double electron detachment cross sections were found to increase with increasing charge state of the precursor anion. The experimental findings are supported by the calculations of the total electron capture cross sections, based on the classical over-the-barrier model, restricted to a simple uniformly charged linear protein structure and a near-end electron capture.

Fragmentation of pure and hydrated clusters of 5Br-uracil by low energy carbon ions: observation of hydrated fragments.

The fragmentation of the isolated 5-bromouracil (5BrU) molecule and pure and nano-hydrated 5BrU clusters induced by low energy 12C4+ ions has been studied. A comparison indicates that the environment, on the one hand, protects the system against the complete break-up into small fragments, but, on the other hand, triggers 'new' pathways for fragmentation, for example the loss of the OH group. The most striking result is the observation of several series of hydrated fragments in the hydrated cluster case, with water molecules bound to hydrophilic sites of 5BrU. This highlights the strong interaction between 5BrU and water molecules and the blocking of specific fragmentation pathways, such as the loss of the BrC2H group for example.

[Light sources usable by the plastic surgeon in the absence of photographic studio]. / Sources lumineuses utilisables par le chirurgien plasticien en l'absence de studio photographique.

Medical photography is an important part of the medical file and is widely used in medical communication, especially in our discipline. His practice has to be the most standardized and reproducible as possible, which distinguishes it from artistic photography. Photography fix the light reflecting from a subject, so surgeon have to control of the light source in any environment. In the absence of dedicated studio, using external cobra or ring flashes with special diffusers allow the surgeon to have light sources adapted to the different conditions encountered in daily practice.

Determination of Energy-Transfer Distributions in Ionizing Ion-Molecule Collisions.

The ionization and fragmentation of the nucleoside thymidine in the gas phase has been investigated by combining ion collision with state-selected photoionization experiments and quantum chemistry calculations. The comparison between the mass spectra measured in both types of experiments allows us to accurately determine the distribution of the energy deposited in the ionized molecule as a result of the collision. The relation of two experimental techniques and theory shows a strong correlation between the excited states of the ionized molecule with the computed dissociation pathways, as well as with charge localization or delocalization.

[Impulsivity: What are the consequences on compliance to rehabilitation?]. / L'impulsivité : quelles conséquences sur l'adhésion aux soins ? Présentation d'une étude réalisée en addictologie.

INTRODUCTION: Impulsivity is a transnosographical dimension with major consequences on medical care with which psychiatrists are frequently confronted. Furthermore, compliance is a major variable that can affect the efficiency of therapeutics and hospitalizations in psychiatry. A study was carried out in three drug and alcohol rehabilitation hospitalization units to find out if impulsivity can have consequences on compliance. METHOD: The studied population was composed of 85 patients aged from 18 to 70, hospitalized for one or more addiction disorders in a psychometric hospital in Vannes (France). Impulsivity was measured for all patients with the BIS-11 at the beginning of the rehabilitation program. Because no tool to evaluate a total rehab program compliance existed, a scale, used at the end of the hospitalization, was created to measure patient compliance. This score was composed of two simple numeric scales (one used by the nurses and one used by the patient's psychiatrist) and a coefficient of hospitalization duration that was the ratio of completed to planned days of hospitalization. Correlations were made between the different dimensions: impulsivity and compliance, impulsivity and hospitalization conditions, compliance and hospitalization conditions (voluntary or involuntary, planned by a psychiatrist or not, etc.). RESULTS: The main statistically significant result of the study was a negative correlation existing between the motor dimension of impulsivity and compliance (r=-0.37 and P=0.001). The other dimensions of impulsivity showed no significant correlation with compliance score. The study revealed that the different hospitalization conditions showed no link with compliance or impulsivity. CONCLUSION: These original results show that motor impulsive patients need an adaptation of the rehabilitation programs. Shorter programs might be more efficient.

Rapid onset of squamous cell carcinoma in a thin skin graft donor site.

BACKGROUND: Squamous cell carcinomas are malignant tumours of epithelial origin that can appear on sites subjected to chronic inflammation after a period of several years. The rapid development of squamous cell carcinoma at the donor site for a thin skin graft is a rare and poorly understood situation. PATIENTS AND METHODS: We report the case of a patient undergoing thin skin grafting to cover the area of removal of a vertex squamous cell carcinoma and in whom squamous cell carcinoma appeared at the donor site within 9 weeks. DISCUSSION: In our case, we ruled out intraoperative contamination because two sets of surgical instruments were used. Given the number of cases reported in the literature, a chance event seems unlikely. The hypothesis of an acute inflammatory process caused by scarring of the thin skin graft site appears to us the most convincing. Development of cancer at the graft donor site may thus be added to the list of complications of thin skin grafting.

Childhood neglect predicts disorganization in schizophrenia through grey matter decrease in dorsolateral prefrontal cortex.

OBJECTIVE: Psychosocial trauma during childhood is associated with schizophrenia vulnerability. The pattern of grey matter decrease is similar to brain alterations seen in schizophrenia. Our objective was to explore the links between childhood trauma, brain morphology and schizophrenia symptoms. METHOD: Twenty-one patients with schizophrenia stabilized with atypical antipsychotic monotherapy and 30 healthy control subjects completed the study. Anatomical MRI images were analysed using optimized voxel-based morphometry (VBM). Childhood trauma was assessed with the Childhood Trauma Questionnaire, and symptoms were rated on the Scale for the Assessment of Negative Symptoms (SANS) and Scale for the Assessment of Positive Symptoms (SAPS) (disorganization, positive and negative symptoms). In the schizophrenia group, we used structural equation modelling in a path analysis. RESULTS: Total grey matter volume was negatively associated with emotional neglect (EN) in patients with schizophrenia. Whole-brain VBM analyses of grey matter in the schizophrenia group revealed a specific inversed association between EN and the right dorsolateral prefrontal cortex (DLPFC). Path analyses identified a well-fitted model in which EN predicted grey matter density in DLPFC, which in turn predicted the disorganization score. CONCLUSION: Our findings suggest that EN during childhood could have an impact on psychopathology in schizophrenia, which would be mediated by developmental effects on brain regions such as the DLPFC.

Site- and state-selected photofragmentation of 2Br-pyrimidine.

The fragmentation of the 2Br-pyrimidine molecule following direct valence photoionization or inner shell excitation has been studied by electron-ion coincidence experiments. 2Br-pyrimidine has been chosen as a model for the class of pyrimidinic building blocks of three nucleic acids and several radiosensitizers. It is known that the site- and state-localization of energy deposition, typical of inner shell excitation, results in the enhancement of the total ion yield as well as in changes in the relative intensity of the different fragmentation channels. Here we address the question of the origin of this selective fragmentation by using electron-ion coincidence techniques. The results show that the fragmentation is strongly selective in the final singly charged ion state, independently of the process that leads to the population of that state, and the dominant fragmentation patterns correlate with the nearest appearance potential.

Formation of H2 from internally heated polycyclic aromatic hydrocarbons: excitation energy dependence.

We have investigated the effectiveness of molecular hydrogen (H2) formation from Polycyclic Aromatic Hydrocarbons (PAHs) which are internally heated by collisions with keV ions. The present and earlier experimental results are analyzed in view of molecular structure calculations and a simple collision model. We estimate that H2 formation becomes important for internal PAH temperatures exceeding about 2200 K, regardless of the PAH size and the excitation agent. This suggests that keV ions may effectively induce such reactions, while they are unlikely due to, e.g., absorption of single photons with energies below the Lyman limit. The present analysis also suggests that H2 emission is correlated with multi-fragmentation processes, which means that the [PAH-2H](+) peak intensities in the mass spectra may not be used for estimating H2-formation rates.

Fragmentation of anthracene C14H10, acridine C13H9N and phenazine C12H8N2 ions in collisions with atoms.

We report experimental total, absolute, fragmentation cross sections for anthracene C14H10, acridine C13H9N, and phenazine C12H8N2 ions colliding with He at center-of-mass energies close to 100 eV. In addition, we report results for the same ions colliding with Ne, Ar, and Xe at higher energies. The total fragmentation cross sections for these three ions are the same within error bars for a given target. The measured fragment mass distributions reveal significant contributions from both delayed (≫10(-12) s) statistical fragmentation processes as well as non-statistical, prompt (∼10(-15) s), single atom knockout processes. The latter dominate and are often followed by secondary statistical fragmentation. Classical Molecular Dynamics (MD) simulations yield separate cross sections for prompt and delayed fragmentation which are consistent with the experimental results. The intensity of the single C/N-loss peak, the signature of non-statistical fragmentation, decreases with the number of N atoms in the parent ion. The fragment intensity distributions for losses of more than one C or N atom are rather similar for C14H10 and C13H9N but differ strongly for C12H8N2 where weak C-N bonds often remain in the fragments after the first fragmentation step. This greatly increases their probability to fragment further. Distributions of internal energy remaining in the fragments after knockout are obtained from the MD simulations.

Absolute fragmentation cross sections in atom-molecule collisions: scaling laws for non-statistical fragmentation of polycyclic aromatic hydrocarbon molecules.

We present scaling laws for absolute cross sections for non-statistical fragmentation in collisions between Polycyclic Aromatic Hydrocarbons (PAH/PAH(+)) and hydrogen or helium atoms with kinetic energies ranging from 50 eV to 10 keV. Further, we calculate the total fragmentation cross sections (including statistical fragmentation) for 110 eV PAH/PAH(+) + He collisions, and show that they compare well with experimental results. We demonstrate that non-statistical fragmentation becomes dominant for large PAHs and that it yields highly reactive fragments forming strong covalent bonds with atoms (H and N) and molecules (C6H5). Thus nonstatistical fragmentation may be an effective initial step in the formation of, e.g., Polycyclic Aromatic Nitrogen Heterocycles (PANHs). This relates to recent discussions on the evolution of PAHNs in space and the reactivities of defect graphene structures.

[External canthus reconstruction with tarso-conjunctival transposition flap and Hübner's graft]. / Reconstruction du canthus externe par lambeaux de transposition tarso-conjonctivaux et greffons de Hübner.

The external canthus defects with resection of the superior and inferior eyelids external portion remains difficult to treat. The reconstruction has to focus on both the reconstruction of the tarso-conjunctival plan and the musculo-cutaneous plan but has also to treat the disappearance of the external canthus. Usually the tarso-conjunctival plan is reconstructed by a septal transplant, conqual or of palatine mucous membrane. The technique presented here suggests to use two tarso-conjunctival transposition flaps to reconstruct the external canthus and the canthal external ligament. The palpebral defect is then pulled medialy, and is easily reconstructed by a Hübner's graft. The coverage of these tarso-conjunctival flaps and grafts is realized with local cutaneous or musculo-cutaneous flaps. The aim of this reconstruction is to allow a functional and aesthetic reconstruction with respected lid margins with eyelashes. Thanks to this technique, it is possible to reconstruct external canthus defects up to half of the superior and inferior eyelids.

Formations of dumbbell C118 and C119 inside clusters of C60 molecules by collision with α particles.

We report highly selective covalent bond modifications in collisions between keV alpha particles and van der Waals clusters of C(60) fullerenes. Surprisingly, C(119)(+) and C(118)(+) are the dominant molecular fusion products. We use molecular dynamics simulations to show that C(59)(+) and C(58)(+) ions--effectively produced in prompt knockout processes with He(2+)--react rapidly with C(60) to form dumbbell C(119)(+) and C(118)(+). Ion impact on molecular clusters in general is expected to lead to efficient secondary reactions of interest for astrophysics. These reactions are different from those induced by photons.

Ions colliding with clusters of fullerenes--decay pathways and covalent bond formations.

We report experimental results for the ionization and fragmentation of weakly bound van der Waals clusters of n C60 molecules following collisions with Ar(2+), He(2+), and Xe(20+) at laboratory kinetic energies of 13 keV, 22.5 keV, and 300 keV, respectively. Intact singly charged C60 monomers are the dominant reaction products in all three cases and this is accounted for by means of Monte Carlo calculations of energy transfer processes and a simple Arrhenius-type [C60]n(+) → C60(+)+(n-1)C60 evaporation model. Excitation energies in the range of only ~0.7 eV per C60 molecule in a [C60]13(+) cluster are sufficient for complete evaporation and such low energies correspond to ion trajectories far outside the clusters. Still we observe singly and even doubly charged intact cluster ions which stem from even more distant collisions. For penetrating collisions the clusters become multiply charged and some of the individual molecules may be promptly fragmented in direct knock-out processes leading to efficient formations of new covalent systems. For Ar(2+) and He(2+) collisions, we observe very efficient C119(+) and C118(+) formation and molecular dynamics simulations suggest that they are covalent dumb-bell systems due to bonding between C59(+) or C58(+) and C60 during cluster fragmentation. In the Ar(2+) case, it is possible to form even smaller C120-2m(+) molecules (m = 2-7), while no molecular fusion reactions are observed for the present Xe(20+) collisions.

[Eyebrow reconstruction]. / Ophriopoïèse.

The eyebrow is an essential anatomical area, from a social point of view, so its reconstruction, in case of skin defect, must be as meticulous as possible, with the less residual sequela. Capillary density extremely varies from one person to another and the different methods of restoration of this area should absolutely take this into consideration. We are going to review the various techniques of reconstruction, according to the sex and the surface to cover.

[Eyelid, medial canthus and medial orbital wall reconstruction using a combination of Hübner and conchal grafts with two illustrative cases]. / Reconstruction par greffons de Hübner et conque après exérèse étendue palpébro-cantho-orbitaire médiale - Présentation de deux cas.

Post-ablative medial canthus and medial orbital wall reconstruction may involve various materials. Few articles present such reconstructions using cartilage homografts, and very few opt for conchal cartilage. In some cases of medial orbital wall excision, at least half of the eyelid must also be removed. We present two cases where we decided to use conchal cartilage to reconstruct the medial orbital wall and tarsomarginal Hübner grafts to reconstruct the eyelid. This combination offers several advantages: a very limited resorption, only one operative field and a reduced infection risk.