Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
2.
Eur Phys J C Part Fields ; 82(4): 284, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35464994

RESUMO

The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double- ß decay in 76 Ge using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del Gran Sasso of INFN. After Phase I (2011-2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the half-life sensitivity of Phase II (2015-2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular 228 Th calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in Gerda Phase II corresponding to an exposure of 103.7 kg year. These methods suppress the background by a factor of about 5 in the region of interest around Q ß ß = 2039  keV, while preserving ( 81 ± 3 ) % of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.

3.
Eur Phys J C Part Fields ; 81(6): 505, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34720720

RESUMO

Neutrinoless double- ß decay of 76 Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in 76 Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the Gerda setup. The measured resolutions at the Q-value for double- ß decay of 76 Ge ( Q ß ß  = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (Gerda) experiment and an accumulated exposure of 8.5 kg · year, the background index after analysis cuts is measured to be 4 . 9 - 3.4 + 7.3 × 10 - 4 counts / ( keV · kg · year ) around Q ß ß . This work confirms the feasibility of IC detectors for the next-generation experiment Legend.

4.
Eur Phys J C Part Fields ; 81(8): 682, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34776783

RESUMO

The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double- ß decay in 76 Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The experimental signature of the decay is a monoenergetic signal at Q ß ß = 2039.061 ( 7 )  keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double- ß decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular 228 Th calibrations. In this work, we describe the calibration process and associated data analysis of the full Gerda dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years.

5.
Phys Rev Lett ; 125(1): 011801, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32678643

RESUMO

We present the first search for bosonic superweakly interacting massive particles (super-WIMPs) as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-ß decay experiment which operates high-purity germanium detectors enriched in ^{76}Ge in an ultralow background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c^{2} to 1 MeV/c^{2}. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c^{2} have been set. As an example, at a mass of 150 keV/c^{2} the most stringent direct limits on the dimensionless couplings of axionlike particles and dark photons to electrons of g_{ae}<3×10^{-12} and α^{'}/α<6.5×10^{-24} at 90% credible interval, respectively, were obtained.

6.
Phys Rev Lett ; 125(25): 252502, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33416389

RESUMO

The GERmanium Detector Array (GERDA) experiment searched for the lepton-number-violating neutrinoless double-ß (0νßß) decay of ^{76}Ge, whose discovery would have far-reaching implications in cosmology and particle physics. By operating bare germanium diodes, enriched in ^{76}Ge, in an active liquid argon shield, GERDA achieved an unprecedently low background index of 5.2×10^{-4} counts/(keV kg yr) in the signal region and met the design goal to collect an exposure of 100 kg yr in a background-free regime. When combined with the result of Phase I, no signal is observed after 127.2 kg yr of total exposure. A limit on the half-life of 0νßß decay in ^{76}Ge is set at T_{1/2}>1.8×10^{26} yr at 90% C.L., which coincides with the sensitivity assuming no signal.

7.
Eur Phys J C Part Fields ; 79(11): 978, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31885491

RESUMO

The GERmanium Detector Array (Gerda) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double-beta decay of 76 Ge into 76 Se+2e - . Gerda has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new 76Ge enriched detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the Hades underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for Gerda Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the accuracy of pulse shape simulation codes.

8.
Science ; 365(6460): 1445-1448, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31488705

RESUMO

A discovery that neutrinos are Majorana fermions would have profound implications for particle physics and cosmology. The Majorana character of neutrinos would make possible the neutrinoless double-ß (0νßß) decay, a matter-creating process without the balancing emission of antimatter. The GERDA Collaboration searches for the 0νßß decay of 76Ge by operating bare germanium detectors in an active liquid argon shield. With a total exposure of 82.4 kg⋅year, we observe no signal and derive a lower half-life limit of T 1/2 > 0.9 × 1026 years (90% C.L.). Our T 1/2 sensitivity, assuming no signal, is 1.1 × 1026 years. Combining the latter with those from other 0νßß decay searches yields a sensitivity to the effective Majorana neutrino mass of 0.07 to 0.16 electron volts.

9.
Phys Rev Lett ; 120(13): 132503, 2018 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-29694176

RESUMO

The GERDA experiment searches for the lepton-number-violating neutrinoless double-ß decay of ^{76}Ge (^{76}Ge→^{76}Se+2e^{-}) operating bare Ge diodes with an enriched ^{76}Ge fraction in liquid argon. The exposure for broad-energy germanium type (BEGe) detectors is increased threefold with respect to our previous data release. The BEGe detectors feature an excellent background suppression from the analysis of the time profile of the detector signals. In the analysis window a background level of 1.0_{-0.4}^{+0.6}×10^{-3} counts/(keV kg yr) has been achieved; if normalized to the energy resolution this is the lowest ever achieved in any 0νßß experiment. No signal is observed and a new 90% C.L. lower limit for the half-life of 8.0×10^{25} yr is placed when combining with our previous data. The expected median sensitivity assuming no signal is 5.8×10^{25} yr.

10.
RBM rev. bras. med ; 72(4)abr. 2015.
Artigo em Português | LILACS | ID: lil-749257

RESUMO

Este trabalho teve por objetivo apresentar uma revisão e análise crítica da adenomiose, seu impacto sobre a vida da mulher, revelando sua alta prevalência em cirurgias e dando ênfase aos tratamentos clínicos disponíveis. Pode-se observar uma alta prevalência da doença em exames anatomopatológicos pós-histerectomia, acompanhado ou não, previamente, de clínica associada. O tratamento farmacológico depende da clínica apresentada, desejo de engravidar e idade da paciente. As informações sobre a eficácia das terapêuticas devem ser revistas à medida que surgirem estudos clínicos com evidências mais concretas e confiáveis, já que o único tratamento curativo atualmente é a histerectomia.


Assuntos
Terapêutica , Adenomiose , Diagnóstico
11.
Phys Rev Lett ; 111(12): 122503, 2013 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-24093254

RESUMO

Neutrinoless double beta decay is a process that violates lepton number conservation. It is predicted to occur in extensions of the standard model of particle physics. This Letter reports the results from phase I of the Germanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory (Italy) searching for neutrinoless double beta decay of the isotope (76)Ge. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kg yr. A blind analysis is performed. The background index is about 1 × 10(-2) counts/(keV kg yr) after pulse shape discrimination. No signal is observed and a lower limit is derived for the half-life of neutrinoless double beta decay of (76)Ge, T(1/2)(0ν) >2.1 × 10(25) yr (90% C.L.). The combination with the results from the previous experiments with (76)Ge yields T(1/2)(0ν)>3.0 × 10(25) yr (90% C.L.).

12.
Breast ; 20(3): 264-70, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21208804

RESUMO

Percutaneous core biopsy (CB) has been introduced to increase the ability of accurately diagnosing breast malignancies without the need of resorting to surgery. Compared to conventional automated 14 gauge needle core biopsy (NCB), vacuum-assisted needle core biopsy (VANCB) allows obtaining larger specimens and has recognized advantages particularly when the radiological pattern is represented by microcalcifications. Regardless of technical improvements, a small percentage of percutaneous CBs performed to detect breast lesions are still classified, according to European and UK guidelines, in the borderline B3 category, including a group of heterogeneous lesions with uncertain malignant potential. We aimed to assess the prevalence and positive predictive values (PPV) on surgical excision (SE) of B3 category (overall and by sub-categories) in a large series of non-palpable breast lesions assessed through VANCB, also comparison with published data on CB. Overall, 26,165 consecutive stereotactic VANCB were identified in 22 Italian centres: 3107 (11.9%) were classified as B3, of which 1644 (54.2%) proceeded to SE to establish a definitive histological diagnosis of breast pathology. Due to a high proportion of microcalcifications as main radiological pattern, the overall PPV was 21.2% (range 10.6%-27.3% for different B3 subtypes), somewhat lower than the average value (24.5%) from published studies (range 9.9%-35.1%). Our study, to date the largest series of B3 with definitive histological assessment on SE, suggests that B3 lesions should be referred for SE even if VANCB is more accurate than NCB in the diagnostic process of non-palpable, sonographically invisible breast lesions.


Assuntos
Biópsia por Agulha/métodos , Neoplasias da Mama/patologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/cirurgia , Detecção Precoce de Câncer , Feminino , Humanos , Itália/epidemiologia , Valor Preditivo dos Testes , Estudos Retrospectivos
13.
Appl Radiat Isot ; 65(7): 858-65, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17419067

RESUMO

In the Abruzzo Region (Central Italy) there is a lack of measurements of gamma-ray activity in soils and waters. For this reason, we have planned to carry out a systematic measurement of soils in the area of the Provincia dell'Aquila, which covers about one-half of the entire region. In this paper we report the results obtained from 56 soil samples, collected in the northern part of the area of interest (about one-fourth of the total area under study). The results, in terms of content of uranium, thorium and potassium and the activity of caesium are reported, as well as the details on the experimental procedure. The results show a limited content of K and U, with no large variations from site to site, in agreement with the expectations based on the knowledge of the geo-lithological nature of the soil. The amount of Th is also quite limited, with a few exceptions where the Th content is up to five times the average value. Caesium, originated from the fall-out following the Chernobyl accident, is very irregularly distributed owing to the complicated orography of the land. Future plans are also shortly discussed.


Assuntos
Radioisótopos de Césio/análise , Radioisótopos de Potássio/análise , Poluentes Radioativos do Solo/análise , Tório/análise , Urânio/análise , Itália , Espectrometria gama/métodos
14.
Minerva Anestesiol ; 65(6): 440-4, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10394817

RESUMO

The prognostic meaning of the routine use of the methods of temporary clipping of the afferent vessel in patients with intracranial aneurysm (Grading 0-III) was the aim of the analysis in this study. In the period 1 January, 1991-31 December 1997, 304 patients underwent surgery for non-giant intracranial aneurysm and a follow-up angiography. 157 patients were operated by routinely using the temporary clipping of the afferent vessel, whereas in 147 patients the surgical procedure was performed by traditional methods. The statistical analysis showed a significant reduction (p < 0.001) in terms of risk of surgical complications in the patients who underwent surgery with the temporary clip method compared to those operated with the traditional method, with a relative risk of such complications about three times greater in the latter. The routine use of temporary clipping offers, therefore, the possibility of a significant improvement of the surgical results, not influenced by a further involvement for the structure, due to the short application time.


Assuntos
Aneurisma Intracraniano/cirurgia , Aneurisma Roto/etiologia , Aneurisma Roto/cirurgia , Feminino , Humanos , Aneurisma Intracraniano/complicações , Aneurisma Intracraniano/diagnóstico , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/cirurgia , Masculino , Procedimentos Neurocirúrgicos/instrumentação , Procedimentos Neurocirúrgicos/métodos , Prognóstico , Estudos Retrospectivos , Instrumentos Cirúrgicos
15.
Ther Drug Monit ; 21(1): 2-7, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10051048

RESUMO

We report pharmacokinetic data on tacrolimus in 14 heart transplant patients (2 women, 12 men). The median age and the median body weight were 55.5 years (range, 23-61 years) and 67.0 kg (55-79 kg), respectively. All patients were maintained on a triple-drug protocol (tacrolimus, azathioprine, and prednisone), with a 7-day antithymocyte globuline induction. The first tacrolimus dose, administered orally 1 to 5 days posttransplant, ranged from 0.03 to 0.4 mg/kg (median = 0.052 mg/kg). The maintenance dose ranged from 0.03 to 0.13 mg/kg/day (administered in two equal doses) to achieve blood levels of 5 of 20 ng/ml, as determined by a microparticle enzyme immunoassay (MEIA). Whole blood samples were drawn just before, at 0.5 hour, and at 1, 2, 3, 4, 6, 8, 10, and 12 hours after the administration of the first dose; trough levels were measured thereafter. The mean oral clearance (CL/F) and apparent volume of distribution (Vd/F) averaged 0.21+/-0.08 L/hour/kg and 2.4+/-0.8 L/kg while the half-life averaged 8.7+/-3.5 hours. Tacrolimus accumulation index during chronic therapy (Rac = Cmin(steady state)/Cmin(first dose) normalized to the same dose) averaged 1.3. Eighty-eight percent of the trough blood levels measured in our patients were within 5 and 20 ng/ml. The incidence of rejection in the study population was extremely low: a prevalence of grade 2 rejection or more, of 0.4+/-0.8 episodes/ patient was observed after a follow-up period of 8.8+/-2.2 months. Only one patient experienced severe renal toxicity, probably because of his preoperative precarious hemodynamic status. Pharmacokinetic data suggest that maintenance tacrolimus daily dose should be equal to 0.1 mg/kg/day to obtain trough blood concentrations of approximately 10 ng/ml. Inter- and intra-patient variability of tacrolimus blood concentration should be expected and justify careful monitoring.


Assuntos
Transplante de Coração , Imunossupressores/farmacocinética , Tacrolimo/farmacocinética , Adulto , Método Duplo-Cego , Feminino , Rejeição de Enxerto/prevenção & controle , Humanos , Imunossupressores/efeitos adversos , Imunossupressores/sangue , Rim/efeitos dos fármacos , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Tacrolimo/efeitos adversos , Tacrolimo/sangue
16.
Clin Ter ; 149(4): 271-5, 1998.
Artigo em Italiano | MEDLINE | ID: mdl-9866888

RESUMO

PURPOSE: To investigate the curative effects of thermal water and thermal muds in various cutaneous pathologies. PATIENTS AND METHODS: Modifications of phmetry and sebometry using sulphur thermal muds in normal, dry and seborrheic skin have been studied. The three groups of patients have been submitted to a 14 day treatment with thermal muds. RESULT: The application of thermal mud normalized the value of cutaneous pH and sebometry. CONCLUSIONS: These beneficial effects are long-lasting in individuals who have a prolonged treatment with thermal muds.


Assuntos
Dermatite Seborreica/terapia , Peloterapia , Fenômenos Fisiológicos da Pele , Pele/fisiopatologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
17.
J Neurosurg Sci ; 42(1 Suppl 1): 77-9, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9800610

RESUMO

The authors' experience in the routine use of temporary clipping procedures in the surgery of endocranial aneurysms is reported. To analyse the validity of such a method we compared the outcome in a series of 153 aneurysms operated according to the traditional procedure (temporary clipping of the afferent vessel only in the case of intraoperative rupture of the aneurysmatic sac) with that of a more recent series of 225 in which the procedure was applied routinely. An unsatisfactory surgical outcome was found in 12.5% and 6.6% of patients respectively, with a corresponding unfavourable outcome in 5.6% and 2.6%.


Assuntos
Aneurisma Intracraniano/cirurgia , Humanos , Complicações Intraoperatórias/prevenção & controle , Neurocirurgia/métodos , Neurocirurgia/tendências , Complicações Pós-Operatórias , Fatores de Tempo , Resultado do Tratamento
18.
Minerva Endocrinol ; 18(1): 21-5, 1993 Mar.
Artigo em Italiano | MEDLINE | ID: mdl-8232118

RESUMO

The relationship between obesity and prevalence of dyslipidemia is well known. Recent studies affirm that differences in fat distribution can be predictive for differences in the prevalence of metabolic disturbances and cardiovascular disease independently of the BMI, presently the most common index of obesity. In order to verify whether body fat distribution can be associated with a higher risk of atherosclerosis, we have evaluated in a group of obese women the eventual presence of endocrine and metabolic diseases. Assessing regional fat distribution, the waist/hip ratio has been shown to be more closely correlated with these diseases than BMI. We have studied two groups of 10 women, comparable for age and BMI: group A aged 45.8 +/- 6.9 years with a BMI of 35.6 +/- 2.8 kg/m2; group B aged 48.3 +/- 3.6 years with a BMI of 38.5 +/- 2.8 kg/m2. The women were divided according to the waist-hip ratio, which was calculated by measuring the circumference of the waist, namely the smallest circumference between the xiphoid and the umbilicus, and the circumference of the hips at the point of the maximum protuberance of the buttocks. The cut-off value for the waist/hip ratio was considered as 0.80 for the reason that this variable is the most accurate cut-off value for abdominal obesity: for group A 0.76 +/- 0.02; for group B 0.89 +/- 0.02 (p < 0.01). All the women were healthy. None of them was in therapy with any kind of drugs, nor was there any restriction to diet. Nobody was a smoker, neither did anyone drink alcoholic beverages.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Tecido Adiposo/patologia , Obesidade/patologia , Somatotipos , Tecido Adiposo/diagnóstico por imagem , Adulto , Pressão Sanguínea , Constituição Corporal , Índice de Massa Corporal , Doenças Cardiovasculares/epidemiologia , Estudos Transversais , Feminino , Teste de Tolerância a Glucose , Humanos , Hidrocortisona/metabolismo , Insulina/sangue , Lipídeos/sangue , Pessoa de Meia-Idade , Obesidade/metabolismo , Fatores de Risco , Ultrassonografia
19.
AJR Am J Roentgenol ; 145(5): 989-93, 1985 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3901711

RESUMO

During sonographic examination of the neck using high-resolution small-parts equipment, the minor neurovascular bundle may be identified in virtually all patients. Postmortem studies in three cadavers demonstrated that this structure is actually the recurrent laryngeal nerve (RLN). Furthermore, findings observed during sonographic examinations of the neck in nine patients with RLN paralysis of unknown origin were reviewed. Compression, displacement, or infiltration of the nerve from thyroid (seven cases) or parathyroid (two cases) nodules were noted, and this allowed the site and cause of the paralysis to be identified.


Assuntos
Nervos Laríngeos/anatomia & histologia , Nervo Laríngeo Recorrente/anatomia & histologia , Ultrassonografia , Humanos , Glândulas Paratireoides/patologia , Nervo Laríngeo Recorrente/patologia , Glândula Tireoide/patologia , Paralisia das Pregas Vocais/diagnóstico , Paralisia das Pregas Vocais/etiologia
20.
Radiology ; 155(3): 607-10, 1985 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3889999

RESUMO

In 12 patients with secondary hyperparathyroidism, 13 parathyroid tumors detected with the use of sonography and confirmed by fine-needle aspiration biopsy were treated by percutaneous injection of absolute ethanol under ultrasonographic guidance. Indications for this procedure were recurrence of parathyroid tumors after previous subtotal surgery, high surgical risk, or refusal of surgery. Significant volume reductions were recorded for the larger glands; in the smaller ones, structural changes were observed as well. Clinical and biochemical therapeutic effects were obtained in most cases of single hyperplastic glands treated. Percutaneous alcoholic ablation of enlarged parathyroid glands can be used in cases of secondary hyperparathyroidism when surgery is contraindicated or problematic; it can also improve responsiveness to medical therapy, delaying the need for surgery.


Assuntos
Etanol/administração & dosagem , Hiperparatireoidismo Secundário/terapia , Injeções/métodos , Neoplasias das Paratireoides/terapia , Ultrassonografia , Adulto , Idoso , Fosfatase Alcalina/sangue , Feminino , Humanos , Hiperparatireoidismo Secundário/sangue , Hiperparatireoidismo Secundário/etiologia , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Neoplasias das Paratireoides/sangue , Neoplasias das Paratireoides/complicações , Recidiva
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA