Dark Matter Search with the XENON1T Experiment: Background Predictions, Data Analysis and Final Results

The XENON1T experiment is currently the most sensitive in the world for the direct search for dark matter (DM). XENON1T employs a dual-phase (liquid-gas) time projection chamber (TPC) featuring 2.0 t liquid xenon (LXe) target mass. The detector is operated in the underground Laboratori Nazionali del Gran Sasso, in Italy. The search for WIMP, the most popular DMcandidate, conducted with the XENON1T detector for a total exposure of 1.0 t-y is presented in this work. The measured background level amounts to 82^{+5}_{-3}\rm{(syst)\pm3\rm{(stat)}}\,(\si{t}\cdot\si{y}\cdot\si{keV})^{-1} , the lowest ever achieved in a direct detection DM experiment. The profile likelihood analysis of data collected in 278.8 live-days finds no significant excess over background. The statistical inference on the WIMP-nucleon spin-independent cross section sets the world-best exclusion limit for WIMP masses above 8\,GeV/c$^2$, with a minimum of $4.1\times10^{-47}$\,cm$^2$ at 30\,GeV/c$^2$ and 90\% confidence level

A METHOD TO CALIBRATE THE HIGH-RESOLUTION CATANIA ASTROPHYSICAL OBSERVATORY SPECTROPOLARIMETER

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Study of the sensitivity of the XENON1T experiment with the profile likelihood method

Oggi sappiamo che la materia ordinaria rappresenta solo una piccola parte dell'intero contenuto in massa dell'Universo. L'ipotesi dell'esistenza della Materia Oscura, un nuovo tipo di materia che interagisce solo gravitazionalmente e, forse, tramite la forza debole, è stata avvalorata da numerose evidenze su scala sia galattica che cosmologica. Gli sforzi rivolti alla ricerca delle cosiddette WIMPs (Weakly Interacting Massive Particles), il generico nome dato alle particelle di Materia Oscura, si sono moltiplicati nel corso degli ultimi anni. L'esperimento XENON1T, attualmente in costruzione presso i Laboratori Nazionali del Gran Sasso (LNGS) e che sarà in presa dati entro la fine del 2015, segnerà un significativo passo in avanti nella ricerca diretta di Materia Oscura, che si basa sulla rivelazione di collisioni elastiche su nuclei bersaglio. XENON1T rappresenta la fase attuale del progetto XENON, che ha già realizzato gli esperimenti XENON10 (2005) e XENON100 (2008 e tuttora in funzione) e che prevede anche un ulteriore sviluppo, chiamato XENONnT. Il rivelatore XENON1T sfrutta circa 3 tonnellate di xeno liquido (LXe) e si basa su una Time Projection Chamber (TPC) a doppia fase. Dettagliate simulazioni Monte Carlo della geometria del rivelatore, assieme a specifiche misure della radioattività dei materiali e stime della purezza dello xeno utilizzato, hanno permesso di predire con accuratezza il fondo atteso. In questo lavoro di tesi, presentiamo lo studio della sensibilità attesa per XENON1T effettuato tramite il metodo statistico chiamato Profile Likelihood (PL) Ratio, il quale nell'ambito di un approccio frequentista permette un'appropriata trattazione delle incertezze sistematiche. In un primo momento è stata stimata la sensibilità usando il metodo semplificato Likelihood Ratio che non tiene conto di alcuna sistematica. In questo modo si è potuto valutare l'impatto della principale incertezza sistematica per XENON1T, ovvero quella sulla emissione di luce di scintillazione dello xeno per rinculi nucleari di bassa energia. I risultati conclusivi ottenuti con il metodo PL indicano che XENON1T sarà in grado di migliorare significativamente gli attuali limiti di esclusione di WIMPs; la massima sensibilità raggiunge una sezione d'urto σ=1.2∙10-47 cm2 per una massa di WIMP di 50 GeV/c2 e per una esposizione nominale di 2 tonnellate∙anno. I risultati ottenuti sono in linea con l'ambizioso obiettivo di XENON1T di abbassare gli attuali limiti sulla sezione d'urto, σ, delle WIMPs di due ordini di grandezza. Con tali prestazioni, e considerando 1 tonnellata di LXe come massa fiduciale, XENON1T sarà in grado di superare gli attuali limiti (esperimento LUX, 2013) dopo soli 5 giorni di acquisizione dati

The Xenon Road to Direct Detection of Dark Matter at LNGS: The XENON Project

Dark matter is a milestone in the understanding of the Universe and a portal to the discovery of new physics beyond the Standard Model of particles. The direct search for dark matter has become one of the most active fields of experimental physics in the last few decades. Liquid Xenon (LXe) detectors demonstrated the highest sensitivities to the main dark matter candidates (Weakly Interactive Massive Particles, WIMP). The experiments of the XENON project, located in the underground INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy, are leading the field thanks to the dual-phase LXe time projection chamber (TPC) technology. Since the first prototype XENON10 built in 2005, each detector of the XENON project achieved the highest sensitivity to WIMP dark matter. XENON increased the LXe target mass by nearly a factor 400, up to the 5.9 t of the current XENONnT detector installed at LNGS in 2020. Thanks to an unprecedentedly low background level, XENON1T (predecessor of XENONnT) set the world best limits on WIMP dark matter to date, for an overall boost of more than 3 orders of magnitude to the experimental sensitivity since the XENON project started. In this work, we review the principles of direct dark matter detection with LXe TPCs, the detectors of the XENON project, the challenges posed by background mitigation to ultra-low levels, and the main results achieved by the XENON project in the search for dark matter

Improvement of survival in patients with intermediate stage (BCLC-B) hepatocellular acrcinoma complicating liver cirrhosis by combination therapy with radiofrequency ablation and transcatheter chemioembolization

Efficacia del trattamento combinato di radiofrequenza e chemioembolizzazione vs. chemioembolizzaione semplice in pazienti selezionati con HCC in stadio intermedio (BCLC score). Approccio con Propensity score matchin

Female sterilization: Update on clinical efficacy, side effects and contraindications.

Purpose: The aim of this review is to compare studies concerning female sterilization in order to define the most suitable approach and device for each patient considering timing, safety, cost-effectiveness, failure rate, complication rate and patient satisfaction. Methods: A systematic literature search was conducted in electronic databases MEDLINE-EMBASE-Sciencedirect and Cochrane Library between 2000 and 2012. All original descriptions, case reports, retrospective and review articles on tubal sterilization methods have been considered. Outcome measures were effectiveness, tolerability, procedure complications and female satisfaction. Results: The ideal female sterilization system should be a simple, safe, highly efficient, easily learned, inexpensive, one-time procedure without negative side-effects. Nowadays, the trans-cervical approach is associated with minimal postoperative pain, allowing short hospitalization and fast resumption of daily activities. Laparoscopic and laparotomic approaches are considered second choices, since, particularly in developing countries, the transcervical hysteroscopic methods will increasingly spread within gynaecological clinical practice. Conclusions: Safety issues, hospital stay, costs and surgeons' experience are important factors in decision-making of the method for female sterilization. Hysteroscopic devices should be preferred when possible. The counselling time remains a fundamental step in choice. The decision concerning method depends on the setting, the surgeon's experience, the country's economical development and the woman's preference

Could in-vitro studies on Ishikawa cell lines explain the endometrial safety of raloxifene? Systematic literature review and starting points for future oncological research.

To evaluate all the in-vitro raloxifene (RAL) mechanisms of action on normal, Ishikawa, and different endometrium-derived cell lines to explain the in-vivo RAL endometrial effects, a systematic literature search was performed in the electronic databases MEDLINE, EMBASE ScienceDirect, and the Cochrane Library for the time period between 2002 and 2012. Outcomes were considered in relation to in-vitro stimulatory, inhibitory, or neutral actions of RAL in Ishikawa cell lines compared with different endometrial-derived cell lines (both cancerous and normal endometrium). We also considered all the RAL molecular mechanisms responsible for the in-vitro effects observed. More than 150 articles were available in the scientific database literature, but only 21 fulfilled our selection criteria. Although in-vitro studies appear to yield conflicting results, most evidence has shown that RAL seems to induce endometrial cell mitochondria-mediated apoptosis, and to inhibit estrogen-related cell proliferation and endometrial carcinogenesis by inducing antiangiogenic factors, and reducing cytoskeletal reorganization. If the endometrial safety profile of RAL is confirmed, in the near future, selective estrogen receptor modulators could represent an efficient alternative adjuvant treatment to tamoxifen (TAM) in women with breast cancer considered to be at an increased risk of endometrial disease. The confirmation of the endometrial safety profile could enable the proposal of RAL by clinicians as the most appropriate treatment for BRCA1-2 patients after prophylactic salpingo-oophorectomy

Combination of radiofrequency ablation and transcatheter arterial chemoembolization improves survival in advanced hepatocellular carcinoma complicating liver cirrhosis

Background: Treatment of hepatocellular carcinoma (HCC) still remains a controversial issue. In particular, for patients with HCC status exceeding the criteria for “curative” options (advanced HCC) there is no defined standard of therapy. Aim: To evaluate efficacy of combined treatment with radiofrequency ablation (RFA) and transcatether arterial chemio-embolization (TACE) in advanced HCC. Materials and Methods: We performed a retrospective study to compare the cumulative survival rate of patients with advanced HCC treated with combined therapy (simultaneous application of TACE and RFA) [RFA-TACE group, n=35] vs. those treated only by TACE [TACE group, n=36] or those treated only by conservative option [Control group, n=36]. HCC was confirmed by imaging and/or histology. All patients were monitored at one-three months after treatment and every six months by imaging to check for treatment success and/or HCC recurrence. In order to minimize possible bias due to the retrospective design, a propensity score approach was used in analysing the results. Results: The median survival time were 31 months for TACE-RFA group, 21 months for patients in TACE group and 10 months in control group, respectively. The 6-month survival rate was 96%, 90% and 78% in TACE-RFA group, TACE group and control group, respectively; the 1-year survival rate was 89%, 75% and 20.3%. At 3 years from HCC diagnosis, 6% of control group patients were alive, versus 34% and 45% of TACE and TACE-RFA group, respectively. Survival rates difference between groups were significant (p=0.011 and p<0.001 TACE and Controls with respect to TACE-RFA group). Treatment allocation (HR 2.14, p=0.022), and complete treatment response were important independent predictors (HR 3.25, p=0.018) of survival. Conclusion: Based on the results of this study we conclude that the combination of RFA and TACE may represent a promising approach for the treatment of advanced HCC complicating liver cirrhosis. nevertheless, a better definition of patient’s characteristics and technical approaches together with larger scale-randomized trials are needed

Could surgeon's expertise resolve the debate about surgery effectiveness in treatment of endometriosis-related infertility?

Purpose: Restoring the anatomical relationship and preserving the function of pelvic organs represent the ideal outcome of surgical intervention in patients suffering from endometriosis-related infertility. The aim of the study was to compare two large cohorts (Group A and Group B) of infertile patients in terms of postsurgical spontaneous/assisted fertility and perioperative surgical outcomes. The surgical treatment was performed by a skilled surgeon (Group A) and a surgeon dedicated to endometriosis-related infertility (Group B). Methods: An observational cohort study on women affected by pelvic endometriosis who underwent laparoscopic treatment (to restore/improve their fertility) was conducted. A comparison, between Group A and Group B, in terms of perioperative surgical outcomes, clinical/ongoing pregnancy and live birth rates, spontaneous pregnancy rate and obstetrical outcome was performed. Results: A significantly higher spontaneous fertility rate (particularly in the first year after surgery) and lower ectopic pregnancy rate were found in Group B. ART success rates were not affected by different surgical approaches. Perioperative and obstetrical outcomes were similar in both groups. Conclusion: In patients affected by endometriosis, the choice between expectant management versus intervention should be personalized: when the estimated probability of natural conception is low, surgery may be considered as a second-line treatment. Conversely, in all other cases surgery should be offered early (as a first-line approach) as it improves the chance of spontaneous conception. The laparoscopic treatment of infertility due to endometriosis must be performed by a skilled specialized surgeon to ensure a complete “pelvic cleanout” while respecting the anatomical structures and reducing the risk of fertility impairment due to surgical procedure

Which luteal phase support is better for each IVF stimulation protocol to achieve the highest pregnancy rate? A superiority randomized clinical trial.

In vitro fertilization (IVF) cycles generate abnormalities in luteal-phase sex steroid concentrations and this represent an important limiting factor to achieve a good pregnancy rate. Although there are evidences about the usefulness of luteal phase support (LPS) after IVF cycles, no consensus exist about the best dose and way of progesterone (PG) administration, the advantages of estradiol (E2) supplementation and which IVF protocol could benefit from one more than other LPS scheme. Aim of the study was to assess the best LPS (low-dose PG, high-dose PG, high-dose PG and E2 supplementation) to achieve the highest clinical/ongoing pregnancy rate according to stimulation protocol, E2 at ovulation induction, endometrial thickness at pick-up and women's age. We conducted a randomized trial on 360 women undergoing IVF (180 treated by long-GnRH agonist, 90 by short-GnRH agonist and 90 by short-GnRH antagonist protocol) and stimulated by recombinant follicle-stimulating hormone alone. Our data demonstrated that high-dose PG is better than low-dose to increase both clinical and ongoing pregnancy rate. E2 supplementation are mandatory in case of short-GnRH antagonist protocol and strongly suggested in all protocols when E2max 35 years, the real advantages of E2 supplementation remain debatable and require further confirmation