Real-time dynamics of vibronic wavepackets within Rydberg and ion-pair states of molecular iodine

Real-time dynamics of vibrationally and electronically excited I2 molecules has been investigated experimentally using the pump-probe technique. A 2-photon excitation was performed either at 269 nm or 266 nm. An electronic and vibrational wavepacket was built as coherent superposition of a few (269 nm excitation) or many (266 nm excitation) Rydberg states of the and series partly coupled with ion-pair states. The probe operated by ionisation or photodetachement. The energy and angular distribution of the resulting photoelectrons, I+ photocations and I- photoanions were monitored. During the dynamics that is turned on by the pump excitation, the wavepacket splits and explores a variety of electronic states of Rydberg and ion-pair character. The experimental results were complemented by molecular dynamics calculations. This provided invaluable information to identify wavepacket motion along ion-pair potential energy curves.

Time-resolved photoelectron spectroscopy of 4-(dimethylamino)benzethyne - an experimental and computational study

We investigated the excited-state dynamics of 4-(dimethylamino)benzethyne (4-DMABE) in a combined theoretical and experimental study using surface-hopping simulations and time-resolved ionisation experiments. The simulations predict a decay of the initially excited S₂ state into the S₁ state in only a few femtoseconds, inducing a subsequent partial twist of the dimethylamino group within ∼100 fs. This leads to drastically reduced Franck-Condon factors for the ionisation transition to the cationic ground state, thus inhibiting the effective ionisation of the molecule, which leads to a vanishing photoelectron signal on a similar timescale as observed in our time-resolved photoelectron spectra. From the phototoelectron spectra, an adiabatic ionisation energy of 7.17 ± 0.02 eV was determined. The experimental decays match the theoretical predictions very well and the combination of both reveals the electronic characteristics of the molecule, namely the role of intramolecular charge transfer (ICT) states in the deactivation pathway of electronically excited 4-DMABE.

[Cancer during pregnancy: Proposal of a clinical care pathway based on a regional cohort]

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.

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 ionization are investigated by means of a table top fs laser and VUV...

Efficient table-top dual-wavelength beamline for ultrafast transient absorption spectroscopy in the soft X-ray region

We present a table-top beamline providing a soft X-ray supercontinuum extending up to 370 eV from high-order harmonic generation with sub-13 fs 1300 nm driving pulses and simultaneous production of sub-5 fs pulses centered at 800 nm. Optimization of high harmonic generation in a long and dense gas medium yields a photon flux of  ~ 1.4 × 106 photons/s/1% bandwidth at 300 eV. The temporal resolution of X-ray transient absorption experiments with this beamline is measured to be 11 fs for 800 nm excitation. This dual-wavelength approach, combined with high flux and high spectral and temporal resolution soft X-ray absorption spectroscopy, is a new route to the study of ultrafast electronic dynamics in carbon-containing molecules and materials at the carbon K-edge.

Disentangling Spectral Phases of Interfering Autoionizing States from Attosecond Interferometric Measurements

We have determined spectral phases of Ne autoionizing states from extreme ultraviolet and midinfrared attosecond interferometric measurements and ab initio full-electron time-dependent theoretical calculations in an energy interval where several of these states are coherently populated. The retrieved phases exhibit a complex behavior as a function of photon energy, which is the consequence of the interference between paths involving various resonances. In spite of this complexity, we show that phases for individual resonances can still be obtained from experiment by using an extension of the Fano model of atomic resonances. As simultaneous excitation of several resonances is a common scenario in many-electron systems, the present work paves the way to reconstruct electron wave packets coherently generated by attosecond pulses in systems larger than helium.

Evidence of depolarization and ellipticity of high harmonics driven by ultrashort bichromatic circularly polarized fields

High harmonics generated by counter-rotating laser fields at the fundamental and second harmonic frequencies have raised important interest as a table-top source of circularly polarized ultrashort extreme-ultraviolet light. However, this emission has not yet been fully characterized: in particular it was assumed to be fully polarized, leading to an uncertainty on the effective harmonic ellipticity. Here we show, through simulations, that ultrashort driving fields and ultrafast medium ionization lead to a breaking of the dynamical symmetry of the interaction, and consequently to deviations from perfectly circular and fully polarized harmonics, already at the single-atom level. We perform the complete experimental characterization of the polarization state of high harmonics generated along that scheme, giving direct access to the ellipticity absolute value and sign, as well as the degree of polarization of individual harmonic orders. This study allows defining optimal generation conditions of fully circularly polarized harmonics for advanced studies of ultrafast dichroisms.

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.

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.

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.

Microwave detection of sulfoxylic acid (HOSOH)

Sulfoxylic acid (HOSOH), a chemical intermediate roughly midway along the path between highly reduced (H2S) and highly oxidized sulfur (H2SO4), has been detected using Fourier transform microwave spectroscopy and double resonance techniques, guided by new high-level CCSD(T) quantum-chemical calculations of its molecular structure. Rotational spectra of the two most stable isomers of HOSOH, the putative ground state with C2 symmetry and the low-lying C(s) rotamer, have been measured to high precision up to 71 GHz, allowing accurate spectroscopic parameters to be derived for both isomers. HOSOH may play a role in atmospheric and interstellar chemistry, and the present work provides the essential data to enable remote sensing and/or radioastronomical searches for these species. Spectroscopic characterization of HOSOH suggests that other transient intermediates in the oxidation of SO2 to H2SO4 may be amenable to laboratory detection as well.

Influence of loco-regional radiation therapy on subsequent cancer risk among BC pts with p53 germline mutations

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Background: The management of breast cancer (BC) patients (pts) with germline p53 mutations, a rare genetic condition, is not the object of specific recommendations. Preclinical data and preliminary clinical observations suggest a theoretically major radio-sensitivity and high risk of secondary radio-induced malignancies. It remains discussed whether the knowledge of a germline p53 mutation may influence treatment (trt) choices and have prognostic importance. We reviewed our cohort of BC diagnosed as first tumor in pts with germline p53 mutations within the past 11 years, with an attempt to describe secondary malignancies occurring after trt of primary tumor. Patients and Methods: 9 pts have been diagnosed and treated in our institution within the past 11 years for BC as first tumor in the context of a documented germline p53 mutation. Their tumor characteristics, treatment and follow-up data were extracted from prospectively-registered medical records. Results: Median age at diagnosis of primary BC was 32 (22–48). 7/9 pts had a family history compatible with Li Fraumeni syndrome, while 2 had no family history. No pt had previous knowledge of her p53 mutation. Primary tumors were ductal carcinoma in situ (4), infiltrating ductal carcinoma (4), phyllode tumor (1). 3 pts had conservative surgery and 6/9 underwent mastectomy (M). 6 received loco-regional radiation therapy (RT). None had prophylactic contra lateral mastectomy. Loco-regional (LRR) and contra-lateral relapses are listed in the Table , as well as incidence of second primaries within or outside radiation field. Second primaries were sarcoma in 3/4 cases and 1 was papillary thyroid carcinoma. Conclusions: Because of high risk of second breast primary and probably very high risk of radio-induced breast cancer, BC pts with germline p53 mutations should be advised bilateral prophylactic mastectomy and avoidance of radiation therapy. In this context, the knowledge of the mutation might be of great importance. [Table: see text]

No significant financial relationships to disclose.

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.