Search

Many astrophysical and cosmological observations point to the presence of Dark Matter (DM) in the universe. Among the potential DM candidates, WIMPs emerge from theories beyond the SM. The XENON Dark Matter Project is one of the leading experiments for DM direct detection, employing a dual-phase xenon TPC. The current phase of the project, XENONnT, features a TPC with a sensitive liquid xenon mass of 5.9 t surrounded by a Gadolinium-loaded water Cherenkov Neutron Veto (NV). A critical challenge in DM detection is distinguishing WIMP-induced NR from the backgrounds. In particular, neutrons emitted by detector materials can mimic WIMP signals, posing a significant threat to the sensitivity to DM. The NV plays a crucial role in mitigating this background by tagging the escaping neutrons through their delayed capture in water. The NV surrounds the TPC, with highly reflective panels and is instrumented with 120 PMTs. In the first two science runs the NV operated with pure water. In this setup, the NV achieved a neutron tagging efficiency of 53%, contributing significantly to the first WIMP analysis in the first XENONnT science run. A blind analysis over a total exposure of 1.1 tonne-year revealed no significant excess over the expected background, establishing the lowest upper limit to the WIMP-nucleon spin-independent cross-section of 2.58×10−47 cm2 for WIMPs of 28 GeV/c2 mass at a 90% confidence level.

Yang An,1– 3,* Xiangbo Xu,1– 3,* Tianshu Ren,1– 3,* Zhenhua Tong,1,4,* Fernando Gomes Romeiro,5 Andrea Mancuso,6 Xiaozhong Guo,1 Xingshun Qi1 1Liver Cirrhosis Study Group, Department of Gastroenterology, General Hospital of Northern Theater Command, Shenyang, 110840, People’s Republic of China; 2Postgraduate College, Shenyang Pharmaceutical University, Shenyang, 110016, People’s Republic of China; 3Department of Pharmacy, General Hospital of Northern Theater Command, Shenyang, 110840, People’s Republic of China; 4Section of Medical Service, General Hospital of Northern Theater Command, Shenyang, 110840, People’s Republic of China; 5Department of Internal Medicine, Botucatu Medical School, UNESP – Univ Estadual Paulista. Av. Prof. Mário Rubens Guimarães Montenegro, s/n Distrito de Rubião Jr, Botucatu, Brazil; 6Medicina Interna 1, ARNAS-Civico, Di Cristina-Benfratelli, Palermo, Italy*These authors contributed equally to this workCorrespondence: Xingshun Qi; Xiaozhong Guo Email xingshunqi@126.com; guo_xiao_zhong@126.comBackground and Aim: Long-term use of non-selective beta blockers (NSBBs) is essential for the prevention of esophageal variceal bleeding in liver cirrhosis but may impair the patient’s adherence. The present study aimed to investigate the adherence to NSBBs to prevent variceal bleeding in cirrhotic patients.Methods: All patients who had an indication of NSBBs for the prophylaxis of variceal bleeding between February 2018 and June 2019 were screened. Clinical pharmacists gave pre-medication education and recorded the adherence to NSBBs during the patients’ hospitalizations. Factors associated with poor adherence were evaluated by univariate logistic regression analysis. Odds ratios (OR) with 95% confidence intervals (CI) were calculated. The relationship between poor adherence during follow-up and variceal bleeding after discharge was also evaluated.Results: Overall, 108 patients were screened

Background and Aim. Spontaneous bacterial peritonitis (SBP) is one of the most common complications of liver cirrhosis. Antibiotics are the main treatment regimen of SBP. Traditional Chinese medicine Xuebijing injection has been used in such patients. Our study aimed to overview the efficacy of Xuebijing injection combined with antibiotics for the treatment of SBP. Method. We searched the PubMed, Embase, China National Knowledge Infrastructure, VIP, and Wanfang databases. The search items included "Xuebijing", "peritonitis", "liver cirrhosis", and "random" to identify all relevant randomized controlled trials (RCTs). The Cochrane risk of bias tool was used to assess the study quality. The odd ratios (ORs) with 95% confidence intervals (CIs) were calculated by using a random-effect model. Heterogeneity was also calculated. Results. A total of 9 RCTs were included. The study quality was unsatisfied. The overall (OR = 2.95, 95% CI = 1.97–4.42, p<0.00001) and complete (OR = 2.18, 95% CI = 1.57–3.04, p<0.00001) responses were significantly higher in the Xuebijing injection combined with antibiotics group than the antibiotics alone group. The incidence of cirrhosis related complications, including hepatic encephalopathy and hepatorenal syndrome, was lower in the Xuebijing injection combined with antibiotics group than the antibiotics alone group. No significant heterogeneity was observed among studies. Conclusion. Additional use of Xuebijing injection may improve the efficacy of antibiotics for the treatment of SBP in liver cirrhosis. However, due to a low level of current evidence, we did not establish any recommendation regarding the use of Xuebijing injection for the treatment of SBP.

Numerous and convincing are the experimental evidences that led to the believe that most of the Universe is constituted by the so-called Dark Matter (DM). Its research has attracted many experimental efforts to the point of being considered the greatest mystery of physics. The most promising candidates to DM are generically named as WIMPs, an acronym for Weakly Interacting Massive Particles.The detectors that have reached the most competitive sensitivity levels have in common the characteristics of being built with ultrapure materials and located underground, shielded from cosmic rays. The XENON project,located at the Laboratori Nazionali del Gran Sasso (LNGS). The XENON1T experiment employed a dual-phase Time Projection Chamber (TPC) with 2t of xenon active mass. The next step of the detector is XENONnT, and is currently in the final assembling stage. With a bigger TPC containing 6t of xenon active mass, the main goal is to improve the detection potential for WIMPs by increasing the sensitivity of one order of magnitude in five years of data taking. That result can be achieved only with a substantial background lowering attained with a reduction of the contaminants of the xenon as well as of the detector materials and finally, with the Neutron Veto system (nVeto); the latter is a detector which tags the radiogenic neutrons coming from the materials of the experiment. The nVeto will employ the gadolinium-loaded water technology to significantly enhance the neutron capture cross-section. It will be instrumented with 120 8'' Hamamatsu R5912 photomultipliers (PMT) featuring high quantum efficiency and low radioactivity. Most of the work done to design and realize the nVeto is the argument of this thesis. In addition, an extensive study of the nVeto PMT performance has been done in a dedicated experimental setup at the LNGS. The complete description of the setup,as well as the results of the nVeto PMT tests, is the other big topic of this thesis.

Diverse osservazioni, su scala astronomica e cosmologica, suggeriscono l'esistenza di Materia Oscura e che questa componga quasi il 90% della materia nell'Universo. Le particelle candidate più promettenti sono le Weakly Interacting Massive Particle. La loro rivelazione è difficile a causa della piccola sezione d'urto prevista; l'osservazione di Materia Oscura necessita quindi di rivelatori ultra puri e ultrasensibili, situati in ambienti in cui i segnali di fondo possano essere ridotti. Il progetto XENON, ai Laboratori Nazionali del Gran Sasso, si pone l'obiettivo di rivelare direttamente le interazioni della Materia Oscura con rivelatori costituiti da una Time Projection Chamber contenente Xeno. La fase attuale del progetto è XENON1T; i primi risultati non hanno evidenziato eventi dovuti a Materia Oscura, permettendo invece di fissare un limite per la sezione d'urto WIMP-nucleo, indipendente dallo spin e di migliorare quelli precedentemente ottenuti. Con lo scopo di aumentare ulteriormente la sensibilità, ed eventualmente confermare un'osservazione da parte di XENON1T, la collaborazione sta lavorano alla fase successiva, prevista per il 2019: XENONnT. Per ridurre il fondo dovuto a neutroni generati dai materiali del rivelatore è in progetto un sistema di Veto di Neutroni basato su scintillatore liquido dopato con Gadolinio (Gd). Tale rivelatore è completato da 120 Fotomoltiplicatori, ovvero dispositivi in grado di convertire il segnale luminoso in un segnale di corrente analizzabile e amplificabile. In questo lavoro di tesi saranno riportati i risultati di primi test di funzionalità di PMT 8" Hamamatsu R5912-100WA-D30, effettuati presso i laboratori dell'Università e della Sezione INFN di Bologna. In particolare è stato misurato il guadagno di tre PMT campione e lo si è confrontato con i valori forniti dalla casa produttrice, allo scopo di valutare un possibile utilizzo dei PMT nel futuro Veto di Neutroni di XENONnT.

Numerous and convincing are the experimental evidences that led to the believe that most of the Universe is constituted by the so-called Dark Matter (DM). Its research has attracted many experimental efforts to the point of being considered the greatest mystery of physics. The most promising candidates to DM are generically named as WIMPs, an acronym for Weakly Interacting Massive Particles.The detectors that have reached the most competitive sensitivity levels have in common the characteristics of being built with ultrapure materials and located underground, shielded from cosmic rays. The XENON project,located at the Laboratori Nazionali del Gran Sasso (LNGS). The XENON1T experiment employed a dual-phase Time Projection Chamber (TPC) with 2t of xenon active mass. The next step of the detector is XENONnT, and is currently in the final assembling stage. With a bigger TPC containing 6t of xenon active mass, the main goal is to improve the detection potential for WIMPs by increasing the sensitivity of one order of magnitude in five years of data taking. That result can be achieved only with a substantial background lowering attained with a reduction of the contaminants of the xenon as well as of the detector materials and finally, with the Neutron Veto system (nVeto); the latter is a detector which tags the radiogenic neutrons coming from the materials of the experiment. The nVeto will employ the gadolinium-loaded water technology to significantly enhance the neutron capture cross-section. It will be instrumented with 120 8'' Hamamatsu R5912 photomultipliers (PMT) featuring high quantum efficiency and low radioactivity. Most of the work done to design and realize the nVeto is the argument of this thesis. In addition, an extensive study of the nVeto PMT performance has been done in a dedicated experimental setup at the LNGS. The complete description of the setup,as well as the results of the nVeto PMT tests, is the other big topic of this thesis.

Diverse osservazioni, su scala astronomica e cosmologica, suggeriscono l'esistenza di Materia Oscura e che questa componga quasi il 90% della materia nell'Universo. Le particelle candidate più promettenti sono le Weakly Interacting Massive Particle. La loro rivelazione è difficile a causa della piccola sezione d'urto prevista; l'osservazione di Materia Oscura necessita quindi di rivelatori ultra puri e ultrasensibili, situati in ambienti in cui i segnali di fondo possano essere ridotti. Il progetto XENON, ai Laboratori Nazionali del Gran Sasso, si pone l'obiettivo di rivelare direttamente le interazioni della Materia Oscura con rivelatori costituiti da una Time Projection Chamber contenente Xeno. La fase attuale del progetto è XENON1T; i primi risultati non hanno evidenziato eventi dovuti a Materia Oscura, permettendo invece di fissare un limite per la sezione d'urto WIMP-nucleo, indipendente dallo spin e di migliorare quelli precedentemente ottenuti. Con lo scopo di aumentare ulteriormente la sensibilità, ed eventualmente confermare un'osservazione da parte di XENON1T, la collaborazione sta lavorano alla fase successiva, prevista per il 2019: XENONnT. Per ridurre il fondo dovuto a neutroni generati dai materiali del rivelatore è in progetto un sistema di Veto di Neutroni basato su scintillatore liquido dopato con Gadolinio (Gd). Tale rivelatore è completato da 120 Fotomoltiplicatori, ovvero dispositivi in grado di convertire il segnale luminoso in un segnale di corrente analizzabile e amplificabile. In questo lavoro di tesi saranno riportati i risultati di primi test di funzionalità di PMT 8" Hamamatsu R5912-100WA-D30, effettuati presso i laboratori dell'Università e della Sezione INFN di Bologna. In particolare è stato misurato il guadagno di tre PMT campione e lo si è confrontato con i valori forniti dalla casa produttrice, allo scopo di valutare un possibile utilizzo dei PMT nel futuro Veto di Neutroni di XENONnT.