Some general principles of coin conservation and the mechanical cleaning process adopted by the Museu Histórico Nacional

O texto apresenta uma coletânea de procedimentos técnicos relativos à limpeza e conservação de moedas metálicas e que resultaram de experiências bem sucedidas realizadas com o acervo do Museu Histórico Nacional, Rio de Janeiro.The text describes technical procedures related to the cleaning and conservation of metallic coins, which resulted from successful experiments performed at the Museu Histórico Nacional, Rio de Janeiro, involving its collection

Precious metals determination in ancient coins by portable ED-XRF spectroscopy with a 238Pu source

A portable X-ray fluorescence system (pXRF) was employed to analyse a set of gold, silver and billon coins from the collection of the Museu Histórico Nacional do Rio de Janeiro (MHN), struck during the Brasil Colônia period, under the Dutch occupation, and in Portuguese mints under the reigns of Fernando I (1367 to 1383) and his successor João I (1383 to 1433). The experimental setup consisted of a mini Si-PIN detector and a radioactive source of 238Pu for the excitation of the samples. The aim of the study was to test the possibilities and limitations of this portable system for the determination of the coins’ base alloys, and to verify whether the results obtained were consistent with historical facts. The Brasil Colônia period coins show about 80.5% gold and 96.8% silver. For the Portuguese coins, we could identify a possible monetary debasement during the reign of João I. No matrix corrections were made for these preliminary results.Un équipement portable à fluorescence X (pFX) a été utilisé pour l’analyse de monnaies en or, en argent et en billon appartenant à la collection du Museu Histórico Nacional de Rio de Janeiro (MHN). Certaines de ces monnaies ont été frappées au Brésil pendant la période Brasil Colônia et sous l’occupation hollandaise, alors que d’autres ont été frappées au Portugal sous les règnes de Ferdinand I (1367-1383) et de son successeur Jean I (1383-1433). Le montage expérimental est constitué d’un mini détecteur Si-PIN et d’une source radioactive de 238Pu, dont la radiation émise est utilisée comme source d’excitation. Le but de ce travail est double : vérifier les possibilités et les limites de ce système portable lors qu’il s’agit de déterminer les alliages constitutifs de monnaies en métal précieux et vérifier les rapports entre l’évolution des compositions des monnaies et les différents faits historiques. Les monnaies appartenant à la période Brasil Colônia sont constituées de 80,5 % d’or et de 96,8 % d’argent et les monnaies frappées au Portugal montrent une dévaluation sous Jean I

Détermination des métaux précieux dans les monnaies anciennes par spectroscopie ED-XRF portable avec une source de 238Pu

International audienceA portable X-ray luorescence system (pXRF) was employed to analyse a set of gold, silver and billon coins from the collection of theMuseu Histórico Nacional do Rio de Janeiro (MHN), struck during the Brasil Colônia period, under the Dutch occupation, and in Portuguesemints under the reigns of Fernando I (1367 to 1383) and his successor João I (1383 to 1433). he experimental setup consisted of a mini Si-PINdetector and a radioactive source of 238Pu for the excitation of the samples. he aim of the study was to test the possibilities and limitations ofthis portable system for the determination of the coins’ base alloys, and to verify whether the results obtained were consistent with historicalfacts. he Brasil Colônia period coins show about 80.5% gold and 96.8% silver. For the Portuguese coins, we could identify a possible monetarydebasement during the reign of João I. No matrix corrections were made for these preliminary results

The first gold coins struck in Brazil: myth or reality?

Besieged in Pernambuco by the Portuguese, the Dutch issued in 1645 and 1646, to pay their soldiers, the first coin inscribed “BRASIL”. Named obsidional, it is said to have been fabricated by melting either African gold or gold tableware. It is only in 1694 that the Brazilian itinerant mint was created in Bahia, and successively closed and transferred to Rio de Janeiro in 1698, to Pernambuco in 1700, and back to Rio de Janeiro in 1702. This itinerary is related to the exhaustion of the local metal supplies, until the discovery of gold in Brazil in the late 1600s. SR-XRF analyses of a small set of coins issued by the Dutch West Indies Company and the first Rio de Janeiro mint show the use of different gold alloys and the ratios of trace elements allow advancing several assumptions on the provenance of the gold.Afin de payer la solde de leurs soldats assiégés par les Portugais à Pernambuco, les Hollandais frappèrent, en 1645 et 1646, les premières monnaies portant l’inscription « BRASIL », dites obsidionales, à partir de la fonte d’or africain ou de vaisselle d’or. Ce n’est qu’en 1694 que le premier atelier itinérant brésilien fut créé à Bahia; il fut ensuite fermé et transféré à Rio de Janeiro en 1698, puis à Pernambuco en 1700 avant de s’installer de nouveau à Rio de Janeiro en 1702. Ces délocalisations successives apparaissent liées à l’épuisement des stocks de métal jusqu’aux découvertes de gisements d’or au Brésil à la fin du xvie siècle. L’analyse par SR-XRF de quelques monnaies émises par la Compagnie Hollandaise des Indes Occidentales et d’autres frappées par le premier atelier de Rio de Janeiro indique que l’utilisation de différents alliages d’or et les teneurs en certains éléments traces apportent quelques indices quant à la provenance de l’or

Effect of lung recruitment and titrated Positive End-Expiratory Pressure (PEEP) vs low PEEP on mortality in patients with acute respiratory distress syndrome - A randomized clinical trial

IMPORTANCE: The effects of recruitment maneuvers and positive end-expiratory pressure (PEEP) titration on clinical outcomes in patients with acute respiratory distress syndrome (ARDS) remain uncertain. OBJECTIVE: To determine if lung recruitment associated with PEEP titration according to the best respiratory-system compliance decreases 28-day mortality of patients with moderate to severe ARDS compared with a conventional low-PEEP strategy. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized trial conducted at 120 intensive care units (ICUs) from 9 countries from November 17, 2011, through April 25, 2017, enrolling adults with moderate to severe ARDS. INTERVENTIONS: An experimental strategy with a lung recruitment maneuver and PEEP titration according to the best respiratory-system compliance (n = 501; experimental group) or a control strategy of low PEEP (n = 509). All patients received volume-assist control mode until weaning. MAIN OUTCOMES AND MEASURES: The primary outcome was all-cause mortality until 28 days. Secondary outcomes were length of ICU and hospital stay; ventilator-free days through day 28; pneumothorax requiring drainage within 7 days; barotrauma within 7 days; and ICU, in-hospital, and 6-month mortality. RESULTS: A total of 1010 patients (37.5% female; mean [SD] age, 50.9 [17.4] years) were enrolled and followed up. At 28 days, 277 of 501 patients (55.3%) in the experimental group and 251 of 509 patients (49.3%) in the control group had died (hazard ratio [HR], 1.20; 95% CI, 1.01 to 1.42; P = .041). Compared with the control group, the experimental group strategy increased 6-month mortality (65.3% vs 59.9%; HR, 1.18; 95% CI, 1.01 to 1.38; P = .04), decreased the number of mean ventilator-free days (5.3 vs 6.4; difference, −1.1; 95% CI, −2.1 to −0.1; P = .03), increased the risk of pneumothorax requiring drainage (3.2% vs 1.2%; difference, 2.0%; 95% CI, 0.0% to 4.0%; P = .03), and the risk of barotrauma (5.6% vs 1.6%; difference, 4.0%; 95% CI, 1.5% to 6.5%; P = .001). There were no significant differences in the length of ICU stay, length of hospital stay, ICU mortality, and in-hospital mortality. CONCLUSIONS AND RELEVANCE: In patients with moderate to severe ARDS, a strategy with lung recruitment and titrated PEEP compared with low PEEP increased 28-day all-cause mortality. These findings do not support the routine use of lung recruitment maneuver and PEEP titration in these patients. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01374022