Probing the dynamics of the photo-induced decarboxylation of neutral and ionic pyruvic acid.

The dynamics of the electronically excited pyruvic acid (PA) and of its unimolecular decomposition upon single photon ionisation are investigated by means of a table top fs laser and VUV synchrotron radiation. The latter is coupled with photo-ion/photo-electron coincidence acquisition devices that allow the identification of the ionic products coming from state-to-state fragmentation upon ionisation. The fs-based setup provides time-resolved mass spectra with 266 nm (= 4.661 eV) excitation and an 800 nm multiphoton probe. For interpretation, we carried out theoretical computations using a composite scheme combining density functional theory full molecular geometric optimisation and post-Hartree-Fock correction inclusion. We therefore determined the neutral and ionic species formed during these experiments and the corresponding dissociation channels. Although several PA isomers are found, we show that solely the most stable isomer of PA (i.e. Tc) is present in the molecular beam prior to ionisation. We determined its adiabatic ionisation energy (AIE = 10.031 ± 0.005 eV). The fragmentation of the Tc+ ion occurs at ∼0.4 eV above the threshold and it is dominated by the CC bond breaking channel, forming the HOCO fragment in conjunction with the CH3CO+ ion. The decarboxylation of Tc+ channels has a minor contribution, although they are more favourable thermodynamically. These findings are in contrast with the dominance of decarboxylation while fragmenting Tc populated in the S1-S3 states. For explanation, we invoke an indirect process populating first a short lived autoionising neutral state located in energy at the HOCO + CH3CO+ dissociation limit. Later on, fragmentation occurs, followed by autoionisation. On the other hand, the fs-based experiment does not reveal any appreciable dynamics for the Tc isomer of PA after a 266 nm excitation because of non-favourable Franck-Condon factors at this energy. In sum, our work highlights the importance of the couplings between the parent ion vibrational modes and the dissociative channels in the vicinity of the loss ionic fragmentation thresholds.

[Cancer during pregnancy: Proposal of a clinical care pathway based on a regional cohort]. / Cancer et grossesse : état des lieux en Occitanie et proposition d'un parcours de soin.

OBJECTIVES: Cancer during pregnancy affects 1 in 1000 pregnancies. This situation requires multidisciplinary team, however there is no care pathway dedicated to these patients. The main objective was to describe oncological, obstetrical, and neonatal care through a regional inventory. Our secondary objective was to define a regional "cancer and pregnancy" care pathway. MATERIAL AND METHOD: We carried out an observational, retrospective study from 2013 to 2019 including 48 women (all cancer types) from 2013 to 2019 in Occitania. Then, we defined an "optimal care pathway" and we assessed whether it was respected in the breast cancer subgroup of our cohort. RESULTS: Live births occurred in 79% of the women included. Maternal treatment was initiated during pregnancy for 67% of our population (44% chemotherapy). The most frequent pregnancy complication was preterm delivery (39%), mainly iatrogenic (86.6%). No patient in the group of breast cancer benefited from all of the ten criteria of the "optimal care pathway" that we proposed. CONCLUSIONS: A coordinated regional care pathway seems necessary to optimize communication between the healthcare providers (oncologists, gynecologists and multidisciplinary prenatal diagnosis centers, pharmacologists, pediatricians, psychologists, and general practitioners). This study identifies weaknesses in the management of women with cancer during pregnancy and suggests regional improvement opportunities.

Molecular frame photoemission by a comb of elliptical high-order harmonics: a sensitive probe of both photodynamics and harmonic complete polarization state.

Due to the intimate anisotropic interaction between an XUV light field and a molecule resulting in photoionization (PI), molecular frame photoelectron angular distributions (MFPADs) are most sensitive probes of both electronic/nuclear dynamics and the polarization state of the ionizing light field. Consequently, they encode the complex dipole matrix elements describing the dynamics of the PI transition, as well as the three normalized Stokes parameters s1, s2, s3 characterizing the complete polarization state of the light, operating as molecular polarimetry. The remarkable development of advanced light sources delivering attosecond XUV pulses opens the perspective to visualize the primary steps of photochemical dynamics in time-resolved studies, at the natural attosecond to few femtosecond time-scales of electron dynamics and fast nuclear motion. It is thus timely to investigate the feasibility of measurement of MFPADs when PI is induced e.g., by an attosecond pulse train (APT) corresponding to a comb of discrete high-order harmonics. In the work presented here, we report MFPAD studies based on coincident electron-ion 3D momentum imaging in the context of ultrafast molecular dynamics investigated at the PLFA facility (CEA-SLIC), with two perspectives: (i) using APTs generated in atoms/molecules as a source for MFPAD-resolved PI studies, and (ii) taking advantage of molecular polarimetry to perform a complete polarization analysis of the harmonic emission of molecules, a major challenge of high harmonic spectroscopy. Recent results illustrating both aspects are reported for APTs generated in unaligned SF6 molecules by an elliptically polarized infrared driving field. The observed fingerprints of the elliptically polarized harmonics include the first direct determination of the complete s1, s2, s3 Stokes vector, equivalent to (ψ, ε, P), the orientation and the signed ellipticity of the polarization ellipse, and the degree of polarization P. They are compared to so far incomplete results of XUV optical polarimetry. We finally discuss the comparison between the outcomes of photoionization and high harmonic spectroscopy for the description of molecular photodynamics.

Attosecond dynamics through a Fano resonance: Monitoring the birth of a photoelectron.

The dynamics of quantum systems are encoded in the amplitude and phase of wave packets. However, the rapidity of electron dynamics on the attosecond scale has precluded the complete characterization of electron wave packets in the time domain. Using spectrally resolved electron interferometry, we were able to measure the amplitude and phase of a photoelectron wave packet created through a Fano autoionizing resonance in helium. In our setup, replicas obtained by two-photon transitions interfere with reference wave packets that are formed through smooth continua, allowing the full temporal reconstruction, purely from experimental data, of the resonant wave packet released in the continuum. In turn, this resolves the buildup of the autoionizing resonance on an attosecond time scale. Our results, in excellent agreement with ab initio time-dependent calculations, raise prospects for detailed investigations of ultrafast photoemission dynamics governed by electron correlation, as well as coherent control over structured electron wave packets.

Long-term oncological results after 400 skin-sparing mastectomies.

OBJECTIVE OF THE STUDY: Skin-sparing mastectomies (SSM) have gained acceptance among teams performing immediate breast reconstruction because this technique provides the best cosmetic outcome. Nevertheless, in France, concerns have been raised that limited skin excision during mastectomy could result in an increased risk of local recurrence especially in invasive breast cancer; many surgeons continue to have reservations regarding the oncologic safety of this operation. This is a retrospective, long-term follow-up study of 400 patients operated and followed by two oncoplastic surgeons. PATIENTS AND METHODS: A total of 400 patients with breast cancer underwent SSM with immediate breast reconstruction from January 1, 1992 to December 31, 2002. The American Joint Committee on Cancer pathological staging was Stage 0 (41.5%), Stage I (33.25%), Stage II (16%), Stage III (7.5%), while 1.75% were non-stageable. RESULTS: With a mean follow-up period of 88 months (range: 13-215 months), the locoregional recurrence rate was 3.5%, the rate of distant metastases was 13.5%, and 83% of patients have remained free of recurrent disease. CONCLUSION: This study provides encouraging results suggesting that skin-sparing mastectomy is a safe and reliable option for the management of selected cases of women with invasive or in situ breast cancer.

Autologous fat transfer in reconstructive breast surgery: indications, technique and results.

AIMS: Reconstructive techniques using flaps to preserve the enveloping skin, and even the nipple areolar complex where there is no neoplastic infiltration, have led to vast improvements in the results of reconstructive breast surgery. To further improve the cosmetic outcome, we have applied the technique of autologous fat transfer or lipoinjection, which has proven very successful in cosmetic surgery, to reconstructive breast surgery, and to the treatment of certain cosmetic sequelae of conservative breast treatment. We report our findings. METHODS: From September 2001 to September 2005, 74 autologous fat transfers were undertaken in 69 patients, with 5 patients receiving injections in both breasts, to improve the cosmetic appearance through resurfacing and to repair certain sequelae of conservative breast treatment. Pre- and postoperative imaging, including MRI, were undertaken to monitor the viability of the fat grafts and detect any suspicious lesions; no suspect lesions were detected either pre- or postoperatively. RESULTS: We did not undertake overcorrection, which creates irregularities of surface or contour. Five cases of cytosteatonecrosis were reported among the 74 procedures. The mean follow-up period for the patients was 11.7 months, ranging from 1 month to 3.2 years. The panel judged improvement to be good to very good in 64 breasts (86.5%) and moderate in 10 breasts (13.5%) primarily due to lack of available adipose material for harvesting in these patients. CONCLUSION: Autologous fat transfer is now a routine procedure in our clinic due to its simplicity, safety, and reproducibility. It is systematically proposed to all of our patients as the final, perfecting procedure of breast reconstruction, irrespective of the technique used for the initial reconstructive procedure, but also to repair certain conservative treatments.

[Nipple areola complex conservation in immediate breast reconstruction: prospective study of 66 cases]. / Conservation aréolo-mamelonnaire en reconstruction mammaire immédiate: étude prospective de 66 cas.

OBJECTIVE OF THE STUDY: Our objective is to define a sub-group of patients in whom skin-sparing mastectomy with immediate reconstruction and preservation of the nipple-areola complex is technically and oncologically feasible without increasing the risk of complications and local recurrence. PATIENTS AND METHODS: Between September 1999 and December 2005, 66 patients presenting an in situ and/or invasive breast carcinoma justifying a mastectomy underwent immediate breast reconstruction preserving the skin and nipple-areolar complex. RESULTS: After a median follow-up of 37 months, definitive conservation of the nipple-areolar complex with good esthetic results was achieved in 71% of the cases. CONCLUSION: This preliminary study provides encouraging results in a selected patient population but requires a longer term follow-up in order to draw definitive conclusions on the oncological safety preserving the nipple-areolar complex.