We present a systematic measurement of the X-ray emission asymmetries in the K-shell dielectronic, trielectronic, and quadruelectronic recombination of free electrons into highly charged ions. Iron ...ions in He-like through O-like charge states were produced in an electron beam ion trap, and the electron-ion collision energy was scanned over the recombination resonances. Two identical X-ray detectors mounted head-on and side-on with respect to the electron beam propagation recorded X-rays emitted in the decay of resonantly populated states. The degrees of linear polarization of X-rays inferred from observed emission asymmetries benchmark distorted-wave predictions of the Flexible Atomic Code for several dielectronic recombination satellite lines. The present method also demonstrates its applicability for diagnostics of energy and direction of electron beams inside hot anisotropic plasmas. Both experimental and theoretical data can be used for modeling of hot astrophysical and fusion plasmas.
In electron–ion collisions, recombination processes play a very important role. Recently, multielectron recombination processes have been highly investigated, as they carry information about ...electron–electron interaction. Among them, the most basic process is dielectronic recombination (DR). The research presented here was conducted using an EBIT at Jagiellonian University. Using X-ray spectroscopy, we conducted research into K-LL, K-LM, K-LN, K-LO and K-MM resonances. The aim of this study was to investigate the contribution of the intershell higher-order recombination processes in collected spectra. A good resolution for the K-LL DR spectrum made it possible to distinguish structures for He- up to C-like Ar ions.
Six fully formulated wind turbine gear oils with the same viscosity grade and different formulations were selected and their physical properties were determined.
Thrust ball bearing friction torque ...tests were performed on a modified Four-Ball Machine at a constant temperature of 80°C under the following operating conditions: speed between 75 and 1200rpm and two loads (700N and 7000N).
The experimental results showed that wind turbine gear oil formulation has a significant influence on rolling bearing friction torque.
•Six wind turbine gear oils were selected. Density and viscosities were measured.•Frictional behaviour of a thrust ball bearing (51107).•Tests were performed in a modified Four-Ball Machine between 75 and 1200rpm.•Friction torque is presented for different loads at constant temperature (80°C).•Rolling and sliding friction torques were determined.
Boerhaave syndrome (BS) is a rare but potentially fatal condition. Although surgery is considered the standard treatment, endoscopic therapy has acquired an important role as a minimally invasive ...management approach. The authors describe 2 cases of middle-aged male patients, presenting with spontaneous esophageal perforation after severe straining and vomiting. In the first case, the patient presented with a bone impaction in the upper esophagus successfully removed by rigid esophagoscopy. After the procedure, a chest X-ray/cervicothoracic computerized tomography scan (CT) showed a left hydropneumothorax and pneumomediastinum with oral contrast leak at the lower esophagus. In the second case, the patient presented to the Emergency Department with severe chest pain after an episode of vomiting. The CT showed a massive pneumomediastinum, subcutaneous emphysema, and an oral contrast leak compatible with BS. The patient was initially submitted to surgical suture, but contrast extravasation persisted after 12 days. After multidisciplinary team discussion of both patients, an upper gastrointestinal endoscopy was performed, which revealed pericentimetric wall defects at the distal esophagus. These were successfully closed using an over-the-scope clip (OTSC). After at least a 9-month follow-up, patients have remained clinically well with no relapse. The authors highlight the severity of these clinical cases and the endoscopic option that proved to be decisive in addressing BS. The favorable outcomes suggest a role for the OTSC approach in closing spontaneous esophageal perforation both as first-line and as rescue therapy after a surgical failure.
Six fully formulated wind turbine gear oils with the same viscosity grade and different formulations were selected and their physical properties were determined.
Cylindrical roller thrust bearing ...friction torque tests were performed on a modified Four-Ball Machine at a constant temperature of 80°C under the following operating conditions: speed between 75 and 1200rpm and two loads (700N and 7000N).
The experimental results showed that wind turbine gear oil formulation has a significant influence on rolling bearing friction torque.
•Six wind turbine gear oils were selected. Density and viscosities were measured.•Frictional behaviour of a cylindrical roller thrust bearing (81107).•Tests were performed in a modified Four-Ball Machine between 75 and 1200rpm.•Friction torque is presented for different loads at constant temperature (80°C).•Rolling and sliding friction torques were determined.
Digital transformation has increased the demand for skilled Information Technology (IT) professionals, to an extent that universities cannot satisfy it with newly graduated students. Furthermore, the ...economical downturn has created difficulties and scarcity of opportunities in other areas of activity. This combination of factors led to the need to consider requalification programmes that enable individuals with diverse specialisations and backgrounds to realign their careers to the IT area. This has led to the creation of many coding bootcamps, providing intensive full-time courses focused on unemployed people or unhappy with their jobs, and individuals seeking a career change. A multidisciplinary group of higher education teachers, in collaboration with several industry stakeholders, have designed and promoted an embedded systems programming course, using an intensive project-based learning approach comprising 6 months of daylong classes and a 9 months internship. Having finished two editions of the programme, a questionnaire was presented to the students that finished successfully, in order to evaluate the long-term benefits to graduates and companies. This paper presents a brief discussion of the programme organisation and pedagogical methodologies, as well as the results of the questionnaire, conducted following a Goal–Question–Metric (GQM) approach. The results demonstrate very positive outcomes, both for graduates and companies.
X-ray spectra of the Fe-L complex Gu, Liyi; Shah, Chintan; Mao, Junjie ...
Astronomy and astrophysics (Berlin),
09/2020, Letnik:
641
Journal Article
Recenzirano
Odprti dostop
The Hitomi results for the Perseus cluster have shown that accurate atomic models are essential to the success of X-ray spectroscopic missions and just as important as the store of knowledge on ...instrumental calibration and astrophysical modeling. Preparing the models requires a multifaceted approach, including theoretical calculations, laboratory measurements, and calibration using real observations. In a previous paper, we presented a calculation of the electron impact cross sections on the transitions forming the Fe-L complex. In the present work, we systematically tested the calculation against cross-sections of ions measured in an electron beam ion trap experiment. A two-dimensional analysis in the electron beam energies and X-ray photon energies was utilized to disentangle radiative channels following dielectronic recombination, direct electron-impact excitation, and resonant excitation processes in the experimental data. The data calibrated through laboratory measurements were further fed into a global modeling of the Chandra grating spectrum of Capella. We investigated and compared the fit quality, as well as the sensitivity of the derived physical parameters to the underlying atomic data and the astrophysical plasma modeling. We further list the potential areas of disagreement between the observations and the present calculations, which, in turn, calls for renewed efforts with regard to theoretical calculations and targeted laboratory measurements.
(1) Background: The pandemic context has limited the social and family contacts of institutionalized older adults, and intervention is urgently needed. The aim of this study is to assess the impact ...of the implementation of a "Geriatric Proximity" intervention on the functioning, satisfaction with social support, affective experience, and feelings of loneliness of institutionalized older adults in the times of the pandemic. (2) Methods: This is a pilot study. An experimental group (subject to the "Geriatric Proximity" intervention) and a control group were constituted. Four assessment instruments were applied to both groups: the satisfaction with social support scale; the elderly nursing core set; the positive and negative affect schedule; and the UCLA loneliness scale. (3) Results: The control group shows no differences between the three measurement instants, while the experimental group shows between first and third measurements (all
< 0.05). We observed a reduction in the scores of loneliness scale, negative affect, and cognition functioning and an increase in satisfaction with social support and positive affect. (4) Conclusions: The intervention "Geriatric Proximity" showed a positive contribution by decreasing loneliness and increasing affectivity, satisfaction with social support, and cognitive function during the pandemic period.
X-linked hypophosphataemic rickets (XLH) is a rare disease caused by a mutation in the phosphate-regulating neutral endopeptidase (PHEX) gene, located on the X chromosome. This gene encodes the ...phosphate-regulating endopeptidase, and its inactivation leads to increased levels of circulating phosphatonins responsible for renal phosphate loss. The treatment for XLH is still carried out with long-term administration of phosphate and calcitriol, which can be complicated by hyperparathyroidism, nephrocalcinosis, renal failure, and hypertension. We describe the case of a four-decade follow-up patient with XLH. When she was diagnosed, at 19 years, due to bone pain and deformities, she was put on therapy with phosphorus and cholecalciferol. Despite the clinical improvement, serum phosphorus remained difficult to control. At the age of 44 years, she developed tertiary hyperparathyroidism and was submitted to parathyroidectomy. Five years later, parathyroid hyperfunction recurred. This time, cinacalcet was started, 30 mg alternating with 60 mg/day. Currently, she is 59-years old and remains with controlled mineral metabolism. The genetic study of this patient revealed a nonsense heterozygous mutation (c.501G>A) in PHEX gene that was not previously described. In this case, the off-label use of cinacalcet resulted in the normalisation of serum parathormone and phosphorus levels, eliminated recurrent secondary hyperparathyroidism, which aggravates the bone fragility inherent to XLH, and prevented a new parathyroidectomy. This report also adds important information to the genetic basis of XLH with the identification of a new nonsense mutation of the PHEX gene.
Introduction: Colonic lipomas are common mesenchymal tumours. They are usually asymptomatic and incidentally diagnosed during endoscopic or radiological examinations. Taking into account their ...typical endoscopic and radiological features and benign nature, tissue sampling, resection or follow-up are generally not required. Case Report: A 61-year-old woman with poor surgical fitness presented with colonic subocclusion and lower gastrointestinal bleeding. A colonoscopy performed 1 month earlier showed a large polypoid lesion with necrotic and ulcerated areas occupying the lumen of the proximal ascending colon with inconclusive histology. An abdominopelvic computed tomography scan with intravenous contrast was done revealing a cecal-colonic intussusception of a heterogeneous mass. The patient was successfully managed conservatively. A delayed revision colonoscopy showed a significantly smaller atypical subepithelial lesion with no necrosis or ulceration. A single, large and deep incision with a pre-cut needle-knife® allowed the direct collection of lesion tissue using standard biopsy forceps through the so-called single-incision needle-knife® (SINK) biopsy technique. Histological examination was compatible with submucosal lipoma. After 18 months of follow-up, the patient remains asymptomatic. Discussion/Conclusion: Colonic lipoma complications are rare and can lead to misdiagnosis; in general, they are surgically managed. A conservative approach and a minimally invasive endoscopic procedure allowed a definite diagnosis avoiding the morbidity and mortality of a major surgical intervention in a high-risk patient.
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