Search for Dark-Matter-Nucleon Interactions via Migdal Effect with DarkSide-50.

Dark matter elastic scattering off nuclei can result in the excitation and ionization of the recoiling atom through the so-called Migdal effect. The energy deposition from the ionization electron adds to the energy deposited by the recoiling nuclear system and allows for the detection of interactions of sub-GeV/c^{2} mass dark matter. We present new constraints for sub-GeV/c^{2} dark matter using the dual-phase liquid argon time projection chamber of the DarkSide-50 experiment with an exposure of (12 306±184) kg d. The analysis is based on the ionization signal alone and significantly enhances the sensitivity of DarkSide-50, enabling sensitivity to dark matter with masses down to 40 MeV/c^{2}. Furthermore, it sets the most stringent upper limit on the spin independent dark matter nucleon cross section for masses below 3.6 GeV/c^{2}.

Search for Dark Matter Particle Interactions with Electron Final States with DarkSide-50.

We present a search for dark matter particles with sub-GeV/c^{2} masses whose interactions have final state electrons using the DarkSide-50 experiment's (12 306±184) kg d low-radioactivity liquid argon exposure. By analyzing the ionization signals, we exclude new parameter space for the dark matter-electron cross section σ[over ¯]_{e}, the axioelectric coupling constant g_{Ae}, and the dark photon kinetic mixing parameter κ. We also set the first dark matter direct-detection constraints on the mixing angle |U_{e4}|^{2} for keV/c^{2} sterile neutrinos.

Constraints on Sub-GeV Dark-Matter-Electron Scattering from the DarkSide-50 Experiment.

We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target. The detector has a very high trigger probability for these signals, allowing for an analysis threshold of three extracted electrons, or approximately 0.05 keVee. We calculate the expected recoil spectra for dark matter-electron scattering in argon and, under the assumption of momentum-independent scattering, improve upon existing limits from XENON10 for dark-matter particles with masses between 30 and 100 MeV/c^{2}.

Low-Mass Dark Matter Search with the DarkSide-50 Experiment.

We present the results of a search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 20 GeV/c^{2} using a target of low-radioactivity argon with a 6786.0 kg d exposure. The data were obtained using the DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso. The analysis is based on the ionization signal, for which the DarkSide-50 time projection chamber is fully efficient at 0.1 keVee. The observed rate in the detector at 0.5 keVee is about 1.5 event/keVee/kg/d and is almost entirely accounted for by known background sources. We obtain a 90% C.L. exclusion limit above 1.8 GeV/c^{2} for the spin-independent cross section of dark matter WIMPs on nucleons, extending the exclusion region for dark matter below previous limits in the range 1.8-6 GeV/c^{2}.

First Evidence for cos2ß>0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity.

We present first evidence that the cosine of the CP-violating weak phase 2ß is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6}BB[over ¯] pairs recorded by the Belle detector. The results of the measurement are sin2ß=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2ß=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle ß of the CKM Unitarity Triangle is ß=[22.5±4.4(stat)±1.2(syst)±0.6(model)]°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→cc[over ¯] data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2ß>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-ß=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.

First Observation of CP Violation in B[over ¯]

We report a measurement of the time-dependent CP asymmetry of B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays, where the light neutral hadron h^{0} is a π^{0}, η, or ω meson, and the neutral D meson is reconstructed in the CP eigenstates K^{+}K^{-}, K_{S}^{0}π^{0}, or K_{S}^{0}ω. The measurement is performed combining the final data samples collected at the ϒ(4S) resonance by the BABAR and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6} BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6} BB[over ¯] pairs recorded by the Belle detector. We measure the CP asymmetry parameters -η_{f}S=+0.66±0.10(stat)±0.06(syst) and C=-0.02±0.07(stat)±0.03(syst). These results correspond to the first observation of CP violation in B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations.

Energy flow between spectral components in 2D broadband stimulated Raman spectroscopy.

We introduce a general theoretical description of non resonant impulsive femtosecond stimulated Raman spectroscopy in a multimode harmonic model. In this technique an ultrashort actinic pulse creates coherences of low frequency modes and is followed by a paired narrowband Raman pulse and a broadband probe pulse. Using closed-time-path-loop (CTPL) diagrams, the response on both the red and the blue sides of the broadband pulse with respect to the narrowband Raman pulse is calculated, the process couples high and low frequency modes, which share the same ground state. The transmitted intensity oscillates between the red and the blue side, while the total number of photons is conserved. The total energy of the probe signal is periodically modulated in time by the coherence created in the low frequency modes.

Observation of Rayleigh-Lamb waves generated by the 2022 Hunga-Tonga volcanic eruption with the POLA detectors at Ny-Ålesund.

The eruption of the Hunga-Tonga volcano in the South Pacific Ocean on January 15, 2022, at about 4:15 UTC, generated a violent explosion, which created atmospheric pressure disturbances in the form of Rayleigh-Lamb waves detected all over the globe. Here we discuss the observation of the Hunga-Tonga shock-wave performed at the Ny-Ålesund Research Station on the Spitsbergen island, by the detectors of the PolarquEEEst experiment and their ancillary sensors. Online pressure data as well as the results of dedicated offline analysis are presented and discussed in details. Results include wave arrival times, wave amplitude measurements and wave velocity calculation. We observed five passages of the shock wave with a significance larger than 3 [Formula: see text] and an amplitude up to 1 hPa. The average propagation velocity resulted to be (308 ± 0.6) m/s. Possible effects of the atmospheric pressure variation associated with the shock-wave multiple passages on the cosmic-ray rate at ground level are also investigated. We did not find any significant evidence of this effect.

The novel Mechanical Ventilator Milano for the COVID-19 pandemic.

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world.

Coherent anti-Stokes Raman spectroscopy of single and multi-layer graphene.

Spontaneous Raman spectroscopy is a powerful characterization tool for graphene research. Its extension to the coherent regime, despite the large nonlinear third-order susceptibility of graphene, has so far proven challenging. Due to its gapless nature, several interfering electronic and phononic transitions concur to generate its optical response, preventing to retrieve spectral profiles analogous to those of spontaneous Raman. Here we report stimulated Raman spectroscopy of the G-phonon in single and multi-layer graphene, through coherent anti-Stokes Raman Scattering. The nonlinear signal is dominated by a vibrationally non-resonant background, obscuring the Raman lineshape. We demonstrate that the vibrationally resonant coherent anti-Stokes Raman Scattering peak can be measured by reducing the temporal overlap of the laser excitation pulses, suppressing the vibrationally non-resonant background. We model the spectra, taking into account the electronically resonant nature of both. We show how coherent anti-Stokes Raman Scattering can be used for graphene imaging with vibrational sensitivity.

Electronic resonances in broadband stimulated Raman spectroscopy.

Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field, and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by a quantum treatment of the matter through density matrix description of the third order nonlinear polarization, we identify the contributions which generate the Raman bands, by taking into account for the cross section of each process.

[Experimental liver transplantation in pigs. Surgical technique and complications]. / Trapianto di fegato sperimentale nel maiale. Tecnica chirurgica e complicanze.

Only recently, in our laboratory of experimental surgery, we started with a protocol for orthotopic liver transplantation (OLT) in a pig model. This was felt as mandatory for experimental purposes as well as for future clinical applications at our center. We report herein our own experience with 41 OLTx. Intraoperative "lethal" complications occurred in up to 32% (14/41) whereas postoperative complications occurred in the remainders at different intervals of time with a maximum survival of 30 days. No attention was paid to prevent rejection-infection episodes. The main cause of death was the primary non-function (PNF) or dis-function (PDF) manifested either intra or postoperatively in 16 out the 41 OLTx (39%). Intraoperative technical errors accounted for up to 9% (4/41 OLTx). Acute hemorrhage gastritis and gastric perforations occurred postoperatively in 6 animals (14%) and represent one of the peculiar aspects of OLT in pig model.

[The prevention of the aorto-mesenteric compression syndrome in interventions for ileoanal anastomoses]. / Prevenzione della sindrome del compasso aorto-mesenterico negli interventi di ileo-ano-anastomosi.

Restorative proctocolectomy with ileal-anal anastomosis can induce a duodenal stenosis due to the compression between superior mesenteric artery (SMA) and aorta when the ileum is pulled-down to the anus stretching the SMA. This situation may require prolonged nasogastric intubation or even surgery. In our experience this occurred in 10% of pts. Aiming to avoid this complication we have performed an intestinal derotation just before ileal-anal anastomosis abolishing any possibility of duodenal compression. Comparing this latter group of patients to those who didn't receive intestinal derotation, we observed a significant reduction of nasogastric tube drainage and of the nasogastric intubation time. We think that intestinal derotation could be effective in preventing SMA syndrome after restorative proctocolectomy and ileal-anal anastomosis.

Prognostic factors in primary and iterative surgery of colorectal liver metastases.

The aim of this study was to evaluate the results of surgery of colorectal liver metastases and assess prognostic factors influencing the outcome. A total of 135 hepatic resections performed in 107 patients was reviewed. The following prognostic factors were analyzed: primary tumor localization, Dukes stage, number and presence of metastases in one or two lobes, synchronous or metachronous occurrence, type of resection, use and modality of chemotherapy. The perioperative morbidity rate was 6.5% and mortality was 1.9%. Overall survival was 41.2% and disease-free survival 31.5% at 5 years. Survival at 5 years was better for patients with metachronous than for those with synchronous lesions (60.9% vs 28.1%; p<0.05). There were no significant differences in terms of long-term survival between patients with synchronous metastases that were excised simultaneously or with a delay of 3-6 months (p=n.s.). Site of the primary tumor, Dukes stage, number of metastases and type of resection did not influence survival. A favorable survival trend was observed in those patients who underwent both neoadjuvant and adjuvant chemotherapy. The overall survival rate at 5 years was 45.3% for patients undergoing a second hepatic resection and 50% for those with a third or a fourth hepatic resection. Liver resection remains the "gold standard" for the treatment of patients with colorectal liver metastases, with metachronous type having a better outcome than synchronous. Simultaneous or delayed surgery for synchronous metastases does not influence prognosis. Iterative resection is very encouraging and justifies an aggressive surgical approach.

Different role of the colonic pouch for low anterior resection and coloanal anastomosis.

BACKGROUND: Functional outcome after sphincter-saving operations can be improved by colonic pouch compared to the straight procedure. However, it is not clear whether the colonic pouch has a different behavior in patients treated by low anterior resection with colorectal (LAR) or coloanal anastomosis (CAA). METHODS: We evaluated the 1-year results of 75 patients who underwent a sphincter-saving operation for rectal carcinoma or villous tumor of the middle or lower third of the rectum: 18 patients underwent coloanal anastomosis (CAA), in 13 patients we performed a coloanal anastomosis with a colonic pouch (PCAA), 20 patients had low anterior resection (LAR) and 24 had LAR with pouch construction (PLAR). The two groups of patients were similar in terms of age and gender. Anorectal function was assessed 12 months after the initial operation by an interview and anorectal manometry. RESULTS: One year after surgery, the daily mean number of defecations was significantly higher in the LAR group than in the other groups (2.0+/-1.5 in CAA group, 2.2+/-1.0 in PCAA, 2.3+/-1.8 in PLAR, 4.1+/-0.7 in LAR; p<0.05). Frequent soiling was observed in all the groups except PLAR. A lower degree of incontinence and a lower frequency of urgency were found in PCAA than in CAA. There were no differences in anal resting pressure and squeeze pressure among the various groups. Greater distensibility and compliance of the neorectum were observed in CAA, PCAA and PLAR compared to LAR, respectively 8.5+/-7.0 ml air/mmHg for CAA, 8.7+/-5.0 ml air/mmHg for PCAA, 6.3+/-4.0 ml air/mmHg for PLAR and 3.1+/-2.7 ml air/mmHg for LAR. A significant inverse linear correlation was present between the mean daily number of defecations and compliance. No difference in sense of incomplete evacuation was observed among the groups of patients. CONCLUSIONS: Colonic J-pouch provides an advantage over straight anastomosis in sphincter-saving operations by reducing the daily number of defecations, and the frequencies of fecal soiling and urgency. The role of the pouch seems to be different in LAR compared to CAA. In fact, in LAR the pouch increases compliance and consequently decreases the daily number of defecations. In CAA, the pouch does not reduce the number of defecations or the compliance, but reduces the frequency of fecal soiling and urgency.

[Major and repeated liver surgery in the multimodal treatment of synchronous and metachronous metastasis of colorectal cancer]. / La chirurgia epatica maggiore e iterativa nel trattamento multimodale delle metastasi sincrone e metacrone da cancro colorettale.

At the present, surgical treatment still represents the only chance of cure for liver metastases from colorectal cancer. Moreover in the last years the new chemotherapic adjuvant and neoadjuvant regimens and the use of radioablative techniques as radiofrequency have improved resectability and even survival. Besides, iterative surgery seems to show more and more encouraging results in terms of disease-free and overall survival, sometimes even in patients already resected for extrahepatic disease. The golden rule is in fact to try to perform every time an R0 resection, with no macro- and possibly microresidual disease.