Commercial gigahertz-class NMR magnets

Nuclear Magnetic Resonance (NMR) spectroscopy is a wide-spread analytical technique which is used in a large range of different fields, such as quality control, food analysis, material science and structural biology. In the widest sense, NMR is an analytical technique to determine the structure of molecules. At the time of writing this manuscript, commercial NMR spectrometers with a proton resonance frequency ≥ 900 MHz are only available from Bruker. In 2019, Bruker installed the first 1.1 GHz (25.8 T) NMR spectrometer at the St. Jude Children Research Hospital in Memphis, Tennessee, followed by the installation of the first 1.2 GHz (28.2 T) NMR spectrometer at the University of Florence in Italy in 2020. These were the first commercial NMR spectrometers operating at magnetic fields in excess of what can be achieved with conventional low temperature superconductors, and which depend on high temperature superconductors to generate the required magnetic field. In this paper, the requirements on commercial NMR magnets are discussed and the history of high-field NMR magnets is reviewed. Bruker’s R&D program for 1.1 and 1.2 GHz NMR magnets and spectrometers will be described, and some of the key properties of these first commercial NMR magnets with high-temperature superconductors are reported.

The Importance of Correspondence in Studying the Activities of the Nineteenth-Century Researchers Expedition of Stephen Sommier and Emile Levier to the Caucasus

The archives of Stephen Sommier and Emile Levier, two Florentine scientists are preserved at the University of Florence Botanical Library archive fund. The archives are comprised of manuscripts and correspondence of the two scientists. Stephen Sommier and Emile Levier travelled to Georgia in 1890 to conduct anthropological researches and to collect and study rare plants. Although a number of articles and books designated for academic circles and a broad circle of readers were published in subsequent years, historians still have not studied their expedition. Correspondence of Sommier and Levier preserved at the Botanical Library has turned out to be a significant resource and example for studying the methodology the nineteenth-century scientists used for long-distance trips.

Introduction

This book is the English version of a work first published in Italian in 1983 and reprinted in 2016. It originated from my tesi di laurea in Latin literature completed a few years earlier at the University of Florence under the supervision of Antonio La Penna, and followed the tenets of that disciplinary sphere, as was customary in Italian academia at the time: it focused on the philological dimension of Ovid’s text, the framing of the individual episode within the structure of the immediate context and the poem as a whole, and analysis of language and style. The main aim of the work was to interpret the two important episodes of Narcissus and Pygmalion—i.e. Ovid’s rewriting of the respective myths—and to highlight the author’s poetics, in response to the considerable interest that had grown in the latter decades of the twentieth century (documented, and greatly bolstered, by G.B. Conte’s influential 1974 essay ...

FLOW CHECK AND ADIABATIC EFFECTIVENESS MEASUREMENTS ON TRADITIONALLY VERSUS ADDITIVELY MANUFACTURED FILM-COOLING HOLES

In the recent years Additive Manufacturing (AM) methods are getting more and more attractive and feasible for the realization of components and subcomponents of gas turbines. They are receiving much attention since, on one hand, the manufacturing of complex 3D geometries is allowed and, on the other, manufacturing and delivery times can be cut down. At the current state of the art, to the authors' knowledge only few applications have yet been commercialized relatively to cooling holes, due to the intrinsic difficulties associated with such a critical feature. Lately, Baker Hughes is studying the possibility to manufacture film-cooling holes via the DMLM technology in order to exploit the flexibility of such innovative manufacturing method and hence eliminate additional processes and lead time. From the open literature it is known that additively manufactured holes can have a more irregular shape and higher roughness than traditional ones, which may lead not only to a reduction in coolant flow but more importantly to a decay of the film-cooling adiabatic effectiveness. For this reason, a test campaign has been conducted in collaboration with the University of Florence (Italy) with the objective of characterizing the performance (minimum passage diameter, flow check and adiabatic effectiveness) of AM vs traditional cylindrical holes on simple-geometry coupons built upon different construction angles. Results were then analyzed in order to fully compare the performance of AM vs traditional film-cooling holes at different operating regimes.

Structural and chemical characterization of dienerite, Ni3As, and its revalidation as a mineral species

ABSTRACT Dienerite, ideally Ni3As, was discovered in 1919 near Radstadt (Salzburg, Austria) and its description and chemical characterization date back to the 1920s. The paucity of reliable experimental data, as well as the absence of any other documented occurrences of such a mineral in over 80 years, led to the supposition of a typographic error in the transcription of the original chemical analysis, suggesting the mineral might in fact be nickelskutterudite [(Ni,Co,Fe)As3]. As a consequence, the mineral was discredited and deleted in the post-2006 IMA list of valid mineral species. Nonetheless, several minerals having a metal/As ratio close to 3:1 and a description fitting that of dienerite were reported after its discreditation. Here we report the discovery of minute inclusions in a sample of josephinite from Josephine Creek (Oregon, USA) exhibiting high optical and electron reflectance. Structural and chemical investigations unequivocally showed that a mineral having cubic structure [a = 9.6206(9) Å, sp. gr. I3d; R1 = 0.0353] and ideal chemical formula Ni3As does exist, suggesting that dienerite could in fact be a valid species. The proposal to revalidate dienerite has been approved by the Commission on New Minerals, Nomenclature and Classification (IMA-Proposal 19-E). The neotype is deposited in the mineralogical collections of the Natural History Museum, University of Florence, Italy, under catalogue number 3364/I.

L’Archive Dionysos: une approche méthodologique à l’iconographie théâtrale

"The Dionysos Archive: a Methodological Approach to Theatre Iconography. The article illustrates the Dionysos Digital Archive of Theatrical Iconography, created by the research team of the University of Florence directed by Renzo Guardenti. The Dionysos Archive collects more than 22,000 images accompanied by cataloguing files, relating to the history of Performing Arts from Greek theatre to the first decades of the 20th century. The cataloguing of the images contained in the archive is based on criteria aimed at highlighting their theatrical specificity and responds to a historiographic perspective that privileges the visual dimension of the Performing Arts, of which iconographic documentation constitutes a source of primary importance. Keywords: theatre iconography; history of theatre; performing arts; digital archive; cataloguing "

Andres Neumann’s Theatrical Archive. Sources for the History of Contemporary Performing Arts

"The paper, at the conclusion of the work conducted during the first year of the PhD course in Storia delle Arti e dello Spettacolo (History of Cinema, Music, Fine and Performing Arts) at the University of Florence, briefly describes the structure and content of the theatrical archive of Andres Neumann, preserved at the il Funaro Centro Culturale of Pistoia. The fund is a precious instrument of historiography, because it contains documents relating to the main plays of the international theatre of the last thirty years of the twentieth century. After having presented and discussed some examples of documentary types contained in the archive, in particular regarding Tadeusz Kantor and Anatoly Vasiliev, the paper illustrates the prospects for development of this research project. Keywords: Andres Neumann, contemporary theatre, Tadeusz Kantor, Peter Brook, Pina Bausch, Anatoly Vasiliev, il Funaro Centro Culturale, Rondò di Bacco. "

Study Progress of Important Agricultural Heritage Systems (IAHS): A Literature Analysis

Important Agricultural Heritage Systems (IAHS), as a new type of heritage, has received extensive attention from the international scientific communities. With the increase of IAHS research, reviews on it have been conducted by many scholars. However, visualized research to show future research trends of IAHS are lacking. Therefore, using metrology analysis methods, this study aims at presenting the progress of research and the general development trends of Globally Important Agricultural Heritage Systems (GIAHS) in the world from 2006 to 2020 to provide ideas for the development of countries or regions in the future. This study mapped 292 literatures from Web of Science core collections from 2006 to 2020 by CiteSpace software. The results show that research on IAHS from 2006 to 2020 experienced two stages: the fluctuating increase stage, and the steady growth stage. Author groups from China, Italy, the USA, Japan, etc., contributed many papers on IAHS. Institutions including the Chinese Academy of Sciences, the University of Florence and the University of Padua in Italy, etc., have a relatively high influence on international IAHS research. Agriculture Ecosystems & Environment is the most cited journal. Agricultural Heritage Systems, regeneration, agriculture, agroforestry, dry-stone wall, social capital, instability, and agricultural biodiversity have been hotspots in the past 15 years. The research themes mainly focus on GIAHS, tourism, livelihood assets, and direct georeferencing. Authors in different regions concern different research themes. In the future, the fields of applications and microscopic views, social sciences, applications of standardized quantitative research methods, and broadened international cooperation should be paid more attention.

Thyroidectomy for Cancer: The Surgeon and the Parathyroid Glands Sparing

Background: The diagnosis of thyroid cancer is continuously increasing and consequently the amount of thyroidectomy. Notwithstanding the actual surgical skill, postoperative hypoparathyroidism still represents its most frequent complication. The aims of the present study are to analyze the rate of postoperative hypoparathyroidism after thyroidectomy, performed for cancer by a single first operator, without any technological aid, and to compare the data to those obtained adopting the most recent technological adjuncts developed to reduce the postoperative hypoparathyroidism. Methods: During the period 1997–2020 at the Endocrine Surgery Unit of the Department of Clinical and Experimental Medicine of the University of Florence, 1648 consecutive extracapsular thyroidectomies for cancer (401 with central compartment node dissection) were performed. The percentage of hypoparathyroidism, temporary or permanent, was recorded both in the first period (Group A) and in the second, most recent period (Group B). Total thyroidectomies were compared either with those with central compartment dissection and lobectomies. Minimally invasive procedures (MIT, MIVAT, some transoral) were also compared with conventional. Fisher’s exact and Chi-square tests were used for comparison of categorical variables. p < 0.01 was considered statistically significant. Furthermore, a literature research from PubMed® has been performed, considering the most available tools to better identify parathyroid glands during thyroidectomy, in order to reduce the postoperative hypoparathyroidism. We grouped and analyzed them by technological affinity. Results: On the 1648 thyroidectomies enrolled for the study, the histotype was differentiated in 93.93 % of cases, medullary in 4% and poorly differentiated in the remaining 2.06%. Total extracapsular thyroidectomy and lobectomy were performed respectively in 95.45% and 4.55%. We recorded a total of 318 (19.29%) cases of hypocalcemia, with permanent hypoparathyroidism in 11 (0.66%). In regard to the literature, four categories of tools to facilitate the identification of the parathyroids were identified: (a) vital dye; (b) optical devices; (c) autofluorescence of parathyroids; and (d) autofluorescence enhanced by contrast media. Postoperative hypoparathyroidism had a variable range in the different groups. Conclusions: Our data confirm that the incidence of post-surgical hypoparathyroidism is extremely low in the high volume centers. Its potential reduction adopting technological adjuncts is difficult to estimate, and their cost, together with complexity of application, do not allow immediate routine use. The trend towards increasingly unilateral surgery in thyroid carcinoma, as confirmed by our results in case of lobectomy, is expected to really contribute to a further reduction of postsurgical hypoparathyroidism.