Multiplexed direct-frequency-comb Vernier spectroscopy of carbon dioxide 2ν1 + ν3 ro-vibrational combination band.

We investigated a set of nineteen 12C16O2 transitions of the 2ν1 + ν3 ro-vibrational band in the spectral region from 5064 to 5126 cm-1 at different pressures, using frequency-comb Vernier spectroscopy. Our spectrometer enabled the systematic acquisition of molecular absorption profiles with high precision. Spectroscopic parameters, namely, transition frequency, linestrength, and self-pressure broadening coefficient, have been accurately determined by using a global fit procedure. These data are in agreement with theoretical values contained in HITRAN2016 database [I. E. Gordon et al., J. Quant. Spectrosc. Radiat. Transfer 203, 3-69 (2017)] at the same precision level. A moderate improvement of the line intensity determinations, by a factor 1.5 in the best case [P(10) transition at 5091.6 cm-1], should be noticed, projecting direct-comb-Vernier-spectroscopy as an adequate tool for spectral intensity calibration.

Ultimate Limit in the Spectral Resolution of Extreme Ultraviolet Frequency Combs.

We present the results of direct interferometric measurements on the pulse-to-pulse phase jitter of a metrological, fiber-based, infrared (IR) frequency comb. We show that the short-time evolution of such phase fluctuations, which cannot be actively controlled by any feedback system, imposes a stringent limit on the tooth linewidth of extreme ultraviolet (XUV) combs produced by high-order harmonic conversion, thus explaining the difference of 9 orders of magnitude between the coherence times of state-of-the-art IR and XUV frequency combs.

An ultrastable Michelson interferometer for high-resolution spectroscopy in the XUV.

We developed an ultra-stable and accurately-controllable Michelson interferometer to be used in a deeply unbalanced arm configuration for split-pulse XUV Ramsey-type spectroscopy with high-order laser harmonics. The implemented active and passive stabilization systems allow one to reach instabilities in the nanometer range over meters of relative optical path differences. Producing precisely delayed pairs of pump pulses will generate XUV harmonic pulses that may significantly improve the achievable spectral resolution and the precision of absolute frequency measurements in the XUV.

Optical Kerr effect of liquid and supercooled water: the experimental and data analysis perspective.

The time-resolved optical Kerr effect spectroscopy (OKE) is a powerful experimental tool enabling accurate investigations of the dynamic phenomena in molecular liquids. We introduced innovative experimental and fitting procedures, that enable a safe deconvolution of sample response function from the instrumental function. This is a critical issue in order to measure the dynamics of liquid water. We report OKE data on water measuring intermolecular vibrations and the structural relaxation processes in an extended temperature range, inclusive of the supercooled states. The unpreceded data quality makes possible a solid comparison with few theoretical models: the multi-mode Brownian oscillator model, the Kubo's discrete random jump model, and the schematic mode-coupling model. All these models produce reasonable good fits of the OKE data of stable liquid water, i.e., over the freezing point. The features of water dynamics in the OKE data becomes unambiguous only at lower temperatures, i.e., for water in the metastable supercooled phase. We found that the schematic mode-coupling model provides the more rigorous and complete model for water dynamics, even if its intrinsic hydrodynamic approach does not give a direct access to the molecular information.

Evidence of two distinct local structures of water from ambient to supercooled conditions.

The liquid and supercooled states of water show a series of anomalies whose nature is debated. A key role is attributed to the formation of structural aggregates induced by critical phenomena occurring deep in the supercooled region; the nature of the water anomalies and of the hidden critical processes remains elusive. Here we report a time-resolved optical Kerr effect investigation of the vibrational dynamics and relaxation processes in supercooled bulk water. The experiment measures the water intermolecular vibrations and the structural relaxation process in an extended temperature range, and with unprecedented data quality. A mode-coupling analysis of the experimental data enables to characterize the intermolecular vibrational modes and their interplay with the structural relaxation process. The results bring evidence of the coexistence of two local configurations, which are interpreted as high-density and low-density water forms, with an increasing weight of the latter at low temperatures.

Method for high-resolution frequency measurements in the extreme ultraviolet regime: random-sampling Ramsey spectroscopy.

Ramsey-like schemes have been recently introduced in combination with high-order laser harmonic sources for high-resolution spectroscopic studies in the extreme ultraviolet (XUV). Here we demonstrate a novel method, combining measurements only in a limited subset of randomly chosen time-sampling intervals, which lead us to perform the first high-resolution XUV spectroscopy of atomic argon with a simple split-pulse setup. Providing an experimentally simple and convenient solution to the problem of performing high-resolution absolute frequency measurements in the XUV, our approach will help paving new roads into this challenging spectral territory.

Split-pulse spectrometer for absolute XUV frequency measurements.

A split-pulse spectrometer based on pairs of time-delayed femtosecond pulses can give access to accurate frequency measurements in the extreme ultraviolet (XUV) spectral domain. We demonstrate this approach by measuring the absolute frequency of a single-XUV-photon transition to a bound state of atomic argon excited with the ninth harmonic of an amplified Ti:sapphire laser.

Ramsey spectroscopy of bound atomic states with extreme-ultraviolet laser harmonics.

We report the experimental measurement of Ramsey interference fringes in the single-photon excitation to a high-lying bound state of atomic argon by pairs of phase-locked, time-delayed, extreme UV high-order-harmonic pulses at 87 nm. High-visibility Ramsey fringes are observed for delays larger than 100 ps, thus demonstrating a potential resolving power >10(5) at this wavelength.

Accuracy of remote sensing of water temperature by Raman spectroscopy.

We present an experimental study of the Raman spectrum of pure and synthetic seawater with respect to its salinity and temperature dependence. Experiments made in the laboratory with both cw and pulsed excitation yield information on the limits and applicability of the technique in actual experiments in the field. We have also performed an experimental analysis to determine the presence of stimulated Raman scattering and its influence on the temperature dependence of the spectrum.

[Management of breast cancer in geriatric age; observations on 164 cases]. / La terapia del cancro della mammella in età geriatrica: considerazioni su 164 casi osservati.

Progressive increasing of the life expectancy and the ever more frequent finding of breast cancer in elderly women have focused the attention on the treatment of this pathology in the elderly women. Today most studies support a more aggressive locoregional and systemic therapy in older patients in good physical condition. Authors analyze retrospectively a series of 164 women with breast cancer aged over 69 years treated with combined modality therapy regarding the stage of disease and the status of the patient. Survival by stage, tumor characteristics, node involvement have been compared with a series of patients less than 70 years treated on the same period. Survival curves were not significantly different between the two groups, except for T1 which showed a better survival in younger patients. Also survival according to node involvement did not show significant differences between the two groups. in conclusion, older women should be treated with the same surgical procedures, according to stage, of the younger patients, if they are not too frail to undergo surgery. Only the definitive results of prospective randomized trials will better define the indications and limits of a further reduction of the extent of surgical excision.

[Evaluation of the surgical risk and preparation to major surgical intervention in geriatric surgery]. / La valutazione del rischio operatorio e la preparazione all'intervento di "major surgery" in chirurgia geriatrica.

BACKGROUND: The progress in surgery, anaesthesia, pre and postoperative care improves the number of old patients undergoing major surgery. The preoperative physiologic assessment is very important to identify patients who are at higher risk group and to plan the therapeutical strategics. METHODS: This study has been carried out on 849 patients aged 70 years and over who underwent major surgery; biliary tract surgery in 314 cases, colorectal in 279, gastroesophageal in 144, vascular in 48, jejunal in 32, pulmonary in 13, pancreatic in 11, hepatic in 8. 158 patients underwent urgency surgery. Mortality and morbidity index are related to the age of the patients, the urgency of the treatment, the time required for the operation, the preoperative physiologic assessment. RESULTS: The overall mortality rate was 13.7%: 84 patients died for cardiovascular complications and 32 for pulmonary complications. Mortality rate was 6% after elective surgical treatment and 48% in urgency. The urgency influences considerably the mortality in the group over 80 years than in younger (p < 0.01). The difference in mortality after elective surgery was less significative (p < 0.06). The time required for the operation doesn't influence the mortality rate. CONCLUSION: The authors emphasize that the preoperative physiologic assessment to identify patients at higher risk and an accurate preoperative care may reduce the mortality rate also in patients over 80 years undergoing major surgery. In urgency, when the patients cannot undergo a preoperative assessment and care, the postoperative mortality is higher in the group over 80 years than in younger.

[Latero-lateral portocaval anastomosis in the surgical treatment of portal hypertension: evaluation of a mean follow up of 14 years]. / L'anastomosi porto-cava latero-laterale nel trattamento chirurgico dell'ipertensione portale: valutazione su un follow-up medio di 14 anni.

After the enthusiasm given by the new treatment techniques of complicated portal hypertension (sclerotherapy, TIPS and liver transplantation), various authors in the literature are considering the role of derivative surgery in the treatment of this affection, due to their consolidated experiences and with a long term follow-up. The authors analyse their own long experience, regarding 104 side-to-side porto-caval shunt. It has been done a complete follow-up, of 71 patients, for a period lasting from 4 to 20 years from the operation. Intraoperative mortality was 5,7%, global morbidity was 28%. Haemorrhagic recurrence from rupture of oesophageal varices was found in 2 cases (1 soon after and the other 3 months from the operation). 5 years survival was depending from Child score (96% Child A, 66,4 Child B, 25% Child C) and from the ethology of cirrhosis (70% for alcoholic cirrhosis and 80% for post-hepatitis cirrhosis). The survival was anyhow mainly connected with the persistence of alcohol abuse. The EPS appeared or became worse after the operation in 12 patients out of 71 checked (16.7%). It has never made a patient enable to lead an ordinary life. Due to the results of their own experience, the authors underline the efficacy of side-to-side porto-caval shunt in the prevention of the haemorrhagic recurrence from oesophageal rupture. In selected patients, Child A and B, not responding to the endoscopic treatment and in elective operations, the mortality was very well contained with a good prevention even after many years and a very small occurrence of EPS. For all those reasons, the side-to-side porto-caval shunt still keeps its validity also towards the selective shunts that are much more difficult technically and that can't be done on ascitic patients.

Third-harmonic generation in positively dispersive gases with a novel cell.

The generation of UV third-harmonic radiation by a focused laser beam in a positively dispersive gaseous medium is investigated. The nonlinear gas is confined to a focal half-space by using a differentially pumped gas cell. The resulting density gradient along the beam axis is shown to provide an efficient frequency conversion in spectral regions of positive dispersion. Experimental results obtained in argon at λ ~ 197 nm, which compare favorably with theory, are presented.