High-brightness broad-area diode lasers with enhanced self-aligned lateral structure

Broad-area diode lasers with increased brightness and efficiency are presented, which are fabricated using an enhanced self-aligned lateral structure by means of a two-step epitaxial growth process with an intermediate etching step. In this structure, current-blocking layers in the device edges ensure current confinement under the central stripe, which can limit the detrimental effects of current spreading and lateral carrier accumulation on beam quality. It also minimizes losses at stripe edges, thus lowering the lasing threshold and increasing conversion efficiency, while maintaining high polarization purity. In the first realization of this structure, the current block is integrated within an extreme-triple-asymmetric epitaxial design with a thin p-doped side, meaning that the distance between the current block and the active zone can be minimized without added process complexity. Using this configuration, enhanced self-aligned structure devices with 90 µm stripe width and 4 mm resonator length show up to 20% lower threshold current, 21% narrower beam waist, and slightly higher (1.03 ) peak efficiency in comparison to reference devices with the same dimensions, while slope, divergence angle and polarization purity remain almost unchanged. These results correspond to an increase in brightness by up to 25%, and measurement results of devices with varying stripe widths follow the same trend. © 2020 The Author(s). Published by IOP Publishing Ltd

Montanlandschaft Oberhalbstein – prähistorische Kupferproduktion in Graubünden

Seit Jahrzehnten als prähistorisches Bergbaugebiet bekannt, war das Oberhalbstein in den vergangenen Jahren erstmals Gegenstand systematischer montanarchäologischer Forschungen. Dabei wurden nicht nur Dutzende neue Fundstellen entdeckt, sondern erstmals auch zentrale Verhüttungsbefunde wie Öfen und Röstbette ausgegraben. Zudem konnten gleich mehrere Kupferbergwerke aus der Bronze- und Eisenzeit untersucht werden – eine schweizweite Premiere! Dank ausführlicher Geländearbeiten, Materialauswertungen und Laboranalysen kann nun der gesamte «Oberhalbstein-Prozess» vom Erz bis zum Metall rekonstruiert werden

High-power diode lasers with in-situ-structured lateral current blocking for improved threshold, efficiency and brightness

We present high-power GaAs-based broad-area diode lasers with a novel variant of the enhanced self-aligned lateral structure ‘eSAS’, having a strongly reduced lasing threshold and improved peak conversion efficiency and beam quality in comparison to their standard gain-guided counterparts. To realize this new variant (eSAS-V2), a two-step epitaxial growth process involving in situ etching is used to integrate current-blocking layers, optimized for tunnel current suppression, within the p-Al0.8GaAs cladding layer of an extreme-triple-asymmetric epitaxial structure with a thin p-side waveguide. The blocking layers are thus in close proximity to the active zone, resulting in strong suppression of current spreading and lateral carrier accumulation. eSAS-V2 devices with 4 mm resonator length and varying stripe widths are characterized and compared to previous eSAS variant (eSAS-V1) as well as gain-guided reference devices, all having the same dimensions and epitaxial structure. Measurement results show that the new eSAS-V2 variant eliminates an estimated 89% of lateral current spreading, resulting in a strong threshold current reduction of 29% at 90 μm stripe width, while slope and series resistance are broadly unchanged. The novel eSAS-V2 devices also maintain high conversion efficiency up to high continuous-wave optical power, with an exemplary 90 μm device having 51.5% at 20 W. Near-field width is significantly narrowed in both eSAS variants, but eSAS-V2 exhibits a wider far-field angle, consistent with the presence of index guiding. Nonetheless, eSAS-V2 achieves higher beam quality and lateral brightness than gain-guided reference devices, but the index guiding in this realization prevents it from surpassing eSAS-V1. Overall, the different performance benefits of the eSAS approach are clearly demonstrated

A methodological approach to assess nutrient requirements of heavy pigs in Italy

This paper reports the results of the work of the "Nutrient requirements of heavy pigs" ASPA Commission. The Commission work was mainly focused on the problem of identifying a good and flexible methodology for establishing nutrient requirements of heavy pigs in Italy, in a situation where the major part of the pigs are used for ham and other typical products. Nutrient allowance was considered to be a variable open to manipulation, since its optimal definition depends on the specific circumstances of each single production unit. It appeared that the most logical way to account for the many interactions involved was to integrate available information using computer simulation techniques. A methodology based on the following steps was proposed and analyzed: i) selection of a mathematical model to describe the chemical growth of pigs over time as result of the interactions of genotype, feed and climate; ii) developing suitable equations to predict the quality parameters of the carcass and, if possible, of the single cuts from the body's chemical status and implementation of these equations in the model; iii) identification of production targets and use of the model as a tool to simulate the effect of different genotypes, feed and climate on the productive and the economic results. A model strongly rooted in a theoretical framework, simple enough to be applied in practice and requiring a limited number inputs was selected from literature. From a preliminary evaluation, performed by using experimental calorimetric data, it was concluded that the model was potentially able to accurately predict the chemical growth of pigs under different conditions of feeding and climate. The major lack of knowledge regarded the values of genotypic descriptors of the national pig populations, the evaluation for which some simple experimental protocols are described in literature. Other lack of knowledge involved relationships to predict the anatomical growth and the evolution of quality parameters of carcass and cuts from the chemical composition of the body. If a correlation between the chemical composition of the pig's body and production targets is confirmed, then a link between the farmer and the industry can be established and the model could be used to identify more convenient feeding strategies. The conceptual basis and the way to assess nutrient requirements of heavy pigs have been clearly identified

A methodological approach to assess nutrient requirements of heavy pigs in Italy

This paper reports the results of the work of the "Nutrient requirements of heavy pigs" ASPA Commission. The Commissionwork was mainly focused on the problem of identifying a good and flexible methodology for establishing nutrient requirements of heavy pigs in Italy, in a situation where the major part of the pigs are used for ham and other typical products. Nutrient allowance was considered to be a variable open to manipulation, since its optimal definition depends on the specific circumstances of each single production unit. It appeared that the most logical way to account for the many interactions involved was to integrate available information using computer simulation techniques. A methodology based on the following steps was proposed and analyzed: i) selection of a mathematical model to describe the chemical growth of pigsover time as result of the interactions of genotype, feed and climate; ii) developing suitable equations to predict the qualityparameters of the carcass and, if possible, of the single cuts from the body's chemical status and implementation ofthese equations in the model; iii) identification of production targets and use of the model as a tool to simulate the effectof different genotypes, feed and climate on the productive and the economic results. A model strongly rooted in a theoreticalframework, simple enough to be applied in practice and requiring a limited number inputs was selected from literature.From a preliminary evaluation, performed by using experimental calorimetric data, it was concluded that the modelwas potentially able to accurately predict the chemical growth of pigs under different conditions of feeding and climate.The major lack of knowledge regarded the values of genotypic descriptors of the national pig populations, the evaluationfor which some simple experimental protocols are described in literature. Other lack of knowledge involved relationshipsto predict the anatomical growth and the evolution of quality parameters of carcass and cuts from the chemical compositionof the body. If a correlation between the chemical composition of the pig's body and production targets is confirmed,then a link between the farmer and the industry can be established and the model could be used to identify more convenientfeeding strategies. The conceptual basis and the way to assess nutrient requirements of heavy pigs have beenclearly identified

Mining at the Fringes. High-Altitude Prehistoric Copper Mining in the Oberhalbstein Valley (Grisons, Switzerland)

The mining region of Oberhalbstein, to date sparsely studied, has been the subject of archaeological research since 2013. Two mining areas which lie well above the forest line were studied in the summer of 2017. The Avagna-Ochsenalp site includes multi-phased heap features, of which the earliest phase has been dendrochronologically dated to the 11th century BC. In Cotschens, mining traces in an area of approximately 0.1 km2 from an unknown time period have been observed. Here, the flooded mine 1 was studied in more detail. After the cavity had been drained, 66 wood objects were revealed, including mining tools from the 1st century BC. 14C dating further confirms Late Bronze Age and Early to Late Iron Age activity. Stone tools from the adjacent heap also confirm prehistoric on-site ore processing, a unique find so far in the Oberhalbstein region

[Antinflammatory therapy and cardiovascular risk: a consensus view].

Fin dalla loro scoperta, circa 40 anni fa, i farmaci antinfiammatori non steroidei (FANS) hanno rappresentato una delle classi di farmaci piu utilizzate. Grazie a loro e radicalmente migliorata la capacita di controllare flogosi e dolore sia acuti che cronici. L'efficacia di questi farmaci, specialmente quando assunti cronicamente, si e sempre scontrata con un basso profilo di sicurezza specie a carico dell'apparato gastrointestinale superiore. Si stima che circa l'1% degli utilizzatori di FANS sviluppino lesioni gastro-duodenali importanti (sanguinamento e perforazione) per le quali si deve ricorrere a cure ospedaliere. Malgrado la bassa percentuale di rischio, la vasta diffusione d'uso degli antinfiammatori rende la gastropatia da FANS una causa molto frequente di ospedalizzazione e morte negli USA (1). All

Diagnostic accuracy of a velcro sound detector (VECTOR) for interstitial lung disease in rheumatoid arthritis patients: The InSPIRAtE validation study (INterStitial pneumonia in rheumatoid ArThritis with an electronic device)

Background: Interstitial lung disease (ILD) is a severe systemic manifestation of rheumatoid arthritis (RA). High-resolution computed tomography (HRCT) represents the gold standard for the diagnosis of ILD, but its routine use for screening programs is not advisable because of both high cost and X-ray exposure. Velcro crackles at lung auscultation occur very early in the course of interstitial pneumonia, and their detection is an indication for HRCT. Recently, we developed an algorithm (VECTOR) to detect the presence of Velcro crackles in pulmonary sounds and showed good results in a small sample of RA patients. The aim of the present investigation was to validate the diagnostic accuracy of VECTOR in a larger population of RA patients, compared with that of the reference standard of HRCT, from a multicentre study. Methods: To avoid X-ray exposure, we enrolled 137 consecutive RA patients who had recently undergone HRCT. Lung sounds of all patients were recorded in 4 pulmonary fields bilaterally with a commercial electronic stethoscope (ES); subsequently, all HRCT images were blindly evaluated by a radiologist, and audio data were analysed by means of VECTOR. Results: Fifty-nine of 137 patients showed ILD (43.1%). VECTOR correctly classified 115/137 patients, showing a diagnostic accuracy of 83.9% and a sensitivity and specificity of 93.2 and 76.9%, respectively. Conclusions: VECTOR may represent the first validated tool for the screening of RA patients who are suspected for ILD and who should be directed to HRCT for the diagnosis. Moreover, early identification of RA-ILD could contribute to the design of prospective studies aimed at elucidating unclear aspects of the disease

NEW PERSPECTIVES IN DIAGNOSIS OF INTERSTITIAL LUNG DISEASE RELATED TO RHEUMATOID ARTHRITIS. VALIDATION STUDY OF AN ELECTRONIC STETHOSCOPE AND AD HOC SOFTWARE FOR DETECTION OF PULMONARY CRACKLES

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial joint swelling and tenderness, secondary to the immune-system dysfunction, often complicated by extra-articular manifestations. Among them, lung involvement is very frequent and interstitial lung disease (ILD) represents one of the deleterious complications of RA with impact on both therapeutic approach and overall prognosis. Nevertheless, diagnosis of ILD often remains missing or delayed. Objectives: To preliminarily evaluate the predictive value of pulmonary sound recorded by an electronic stethoscope (ES) and elaborated by an ad hoc software in identification of RA-ILD diagnosed by mean of high resolution computed tomography (HRCT) in a multicenter study. Methods: RA patients who underwent HRCT in the last 12 months were enrolled. They were all auscultated with the ES (Littmann 3200TM 3M, USA), bilaterally, at dorsal level, in at least 3 pulmonary fields (medium and basal). All tracks recorded were analyzed by a suitably developed software capable of recognizing pathological crackles in lung sounds. Results were compared with radiologic findings detected in a blind manner by an expert radiologist. Results: One hundred and six RA patients were enrolled (M/F: 1/2.5, mean age 68.7\ub110.3); among them 45 (42.5%) showed ILD at HRCT. Three patients were excluded because of a low quality of the sound recorded. The algorithm showed a sensitivity and specificity of 72.1% and 84.4%, respectively and a positive/negative predictive value of 69.1% and 86.3%, respectively. Conclusions: Despite preliminary, these data suggest an important role of ES in clinical practice for an early diagnosis of ILD in RA patients and a significant reduction of inappropriate prescription of HRCT. Since very different types of ILD can occur in course of RA, with different radiologic features and localization, proper development of the measurement setup (ES and ad hoc software for the detection of PC) could further increase its predictive value, in particular to avoid incorrect records and misdiagnosis. The routinely employment of ES and proper software, combined to clinical findings (cough, dyspnea) and respiratory lung function, could increase our ability to early identify ILD in RA patients