Ion beam analysis techniques: a powerful set ge tools for identification and sourcing of ancient gems

Gemstones are defined as rare minerals having a high clarity, a high hardness and showing a bright colour and a nice shining. The most important gems are diamond, sapphire and emerald. These gems are callad precious stones. Gems have fascinated man since the earliest times. They have always been sought out by man for their aesthetic and symbolic valué. Due to their scarceness and high '^alue, gems were appreciated by the mighty ones as a sign of their power (emperors ^nd kings, dignitaries of religions ...). Their high hardness and henee strong resismnce to deterioration symbolised the everlastingness of their reign. This last property is interesting from an archaeological point of view: gemstones travel through time without noticeable alteration, even buried in aggressive environment. On the other hand, gems oiay be used several times on different jewels, possibly cut and polished again. Like spices and other precious and sought-after items, gems were brought back from long distance. Accordingly, they are good tracers for ancient trading routes and influence of civilisations. Each civilisation had its own favourite gemstones: lapis lazuli in Egypt; amber and emerald in the Román Empire; gamet in early Middle Ages westem civil isations; jade, ruby and sapphire in Far-East cultures. Moreover, the provenance of some ancient gems such as emeralds or gamets is still debated. For all these reasons, the study of gems kept in museum collections is a promising research fíeld

Complications of arteriovenous hemodialysis access: Recognition and management

English language citations reporting complications of arteriovenous access for hemodialysis are critically reviewed and discussed. Venous hypertension, arterial steal syndrome, and high-output cardiac failure occur as a result of hemodynamic alterations potentiated by access flow. Uremic and diabetic neuropathies are common but may obfuscate recognition of potentially correctable problems such as compression or ischemic neuropathy. Mechanical complications include pseudoaneurysm, which may develop from a puncture hematoma, degeneration of the wall, or infection. Dysfunctional hemostasis, hemorrhage, noninfectious fluid collections, and access-related infections are, in part, manifestations of the adverse effects of uremia on the function of circulating hematologic elements. Impaired erythropoiesis is successfully managed with hormonal stimulation; perhaps, similar therapies can be devised to reverse platelet and leukocyte dysfunction and reduce bleeding and infectious complications

The optimization problem of the shaped knife profiling

Проаналізовано переваги та недоліки процесу гарячого поділу безперервнолитої квадратної заготовки на ножицях з фасонними ножами. Відзначається доцільність проведення теоретичних досліджень розділових операцій на ножицях з використанням методу скінченних елементів (МСЕ). Метою даної роботи було визначення оптимальної форми профілювання фасонного ножа для поділу квадратної заготовки в гарячому стані шляхом математичного моделювання на базі МСЕ. Представлено методику проведення досліджень, що включали два етапи. На першому етапі використовували математичне моделювання відповідно до плану повного факторного експерименту 24 згідно виробничих умов реалізації процесу з ножами що мали значення кута розкриття ножів 90…98° та ухилу контактних поверхонь 3…11°. При обробці даних моделювання були отримані три відносних параметра, два з яких характеризують зминання (затяжка) і загин кінців розкату, і ще один – ромбічність торцевої поверхні. Для кожного з параметрів, отримані лінійні рівняння регресії як функція температури різання та розмірів заготовок, величини кута розкриття ножів та ухилу контактних поверхонь. На другому етапі дослідження вирішували оптимізаційну задачу пошуку мінімуму цільової функції – ромбічності. За результатами відзначено, що оптимальні значення профілювання ножів залежать від вимог, що висуваються до якості зрізу. Введено фактор граничного відхилення зминання і загину кінців, встановлений діапазон його значень та проаналізовано вплив на оптимальні параметри. Запропоновано величини кута розкриття ножів та ухилу контактних поверхонь, за умови мінімізації граничного відхилення зминання і загину кінців у досліджуваних діапазонах температур та розмірів заготовок. Отримано залежності параметрів профілювання ножів від граничного відхилення зминання і загину кінців заготовок після поділу. Результати роботи можуть бути рекомендовані для використання при прийнятті проектно-конструкторських і технологічних рішень в питаннях гарячого розділення безперервнолитої квадратної заготовки фасонними ножами на кут.The advantages and disadvantages of the process of separation in hot condition of billet with square shape by special profiled knives were analyzed. There is expediency of carrying out theoretical researches the separating operations by shears based on finite elements method (FEM) is noted. The purpose of the work was to determine the optimal shape for make form a profiled knife for separating a square billet in a hot state by simulating based on the FEM. A methodology of study realization consisting of two stages is presented. At the first stage, simulating was used in accordance with the plan of the full factorial experiment 24 according to the technological environment for the process implementation with knives having a knife opening angle of 90...98° and a contact surface inclination of 3...11°. At the processing the simulation results, three relative parameters were obtained. Two parameters characterize the crumpling (tightening) and bending of the billet ends, and one more – the rhomboidity of the end surface. For each of the parameters, the linear regression equations obtained as a function of cutting temperature and billet sizes, the knife opening angle and contact surface inclination. At the second stage of the study, the optimization problem of determining the minimum of the objective function – rhomboidity – was solved. According to the results, it was noted that the optimal values of the profiling of knives depend on the requirements for the quality of the cut. The factor of the maximum deviation of crumpling and bending of the ends is introduced. The range of its values is established and the influence on the optimal parameters is analyzed. The values of the knife opening angle and contact surface inclination are proposed, provided that the maximum deviation of the crumpling and bending of the ends, at the studied temperature ranges and sizes of the billets, is minimized. The dependences of the optimal parameters of the profiling of knives on the maximum deviation of the crumpling and bending of the ends of the billets after separation are obtained. Results of work can be recommended for use to get solutions in design and technology questions of hot separation square billet by profiled knife on the angle

Clinical alert: Patterns of oxygen saturation in prolonged recovery from COVID-19 pneumonia

During the second wave of the COVID-19 pandemic in South Africa, a recurrent pattern of prolonged recovery after acute COVID-19 pneumonia, characterised by low oxygen saturation levels for >2 weeks, was observed in an intermediate-care facility in Cape Town. A case study together with a series of 12 patients is presented to illustrate this phenomenon, and two types of ‘sats gap’ are described, which were used by physiotherapists and doctors to monitor daily progress. We attempt to explain this prolonged recovery in terms of the possible pathophysiology, and suggest a number of learning points to guide further research

AB0378 UPGRADING THERAPY STRATEGY IMPROVES PREGNANCY OUTCOME IN ANTIPHOSPHOLIPID SYNDROME: A COHORT MANAGEMENT STUDY

Background:While it is generally agreed that pregnant APS patients should receive personalized treatment, evidence-based guidelines for these patients continue to be lacking.Objectives:The current study was designed as a management cohort study aiming to evaluate the efficacy and safety of different treatment strategies for pregnant APS patients in the attempt to provide some practical suggestions for attending physicians.Methods:One-hundred-twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH)+low-dose aspirin (LDA, 100 mg) [Group I] and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH+LDA [Group II]. LMWH doses were increased throughout the pregnancies depending on the patients' weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study's primary outcome was live births.Results:There were no significant differences in live birth rate between Group I (95.4%) and Group II (87.5%). Even, fetal complication rate was similar in the two groups; the Group II nevertheless had a higher prevalence of maternal and neonatal complications (p=0.0005 and p=0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p=0.0001 and p=0.0005, respectively). Two patients in Group I switched to Group II therapy, six patients in Group II switched to a more intensive treatment strategy (weekly plasma exchange+ fortnightly intravenous immunoglobulins in addition to therapeutic LMWH+LDA). Comparison of the clinical and laboratory characteristics between patients who had shifted to a more intensive therapy and those who did not showed a significant prevalence of history of thrombosis ± pregnancy morbidity (p=0.02, OR 5.96, 95% CI 1.33-26.62) previous pregnancy complications (p=0.02, OR 8.32, 95% CI 1.67-41.3), triple aPL positivity (p <0.0001, OR 97.13, 95% CI 10.6-890) and pregnancy complications (p<0.0001, OR 197,7, 95% CI 10.57-3699) in upgrading group, instead single aPL positivity significantly prevailed (p=0.003, OR 0.06, 95% CI 0.008-0.58) in non-upgrading group. Logistic regression analysis demonstrated that triple aPL positivity was an independent factor for switching to a more effective therapy protocol (p <0.0001, OR 98, 95% CI 10.7-897.54). All eight switched patients achieved a live birth.Conclusion:Using adjusted LMWH doses and upgrading therapy at the first signs of pregnancy complications led to a high rate of live births in a relatively large group of APS patients. The study outlines the criteria for prescribing appropriate therapy for various subsets of these patients and for switching/upgrading the treatment protocol when it is no longer sufficient. Unfortunately, for the moment there are no evidence-based guidelines on the ideal additional treatment in refractory to conventional therapy APS patients. The present results will hopefully help point the direction of future clinical trials investigating the efficacy and safety of the different therapies on large numbers of APS pregnant patients in order to identify the benefits and limits of different treatment strategies administered from the beginning of pregnancy.Disclosure of Interests:Ariela Hoxha Speakers bureau: Celgene, UCB, Novartis, Sanofi, Werfen, Maria Favaro: None declared, Antonia Calligaro: None declared, Teresa Del Ross: None declared, Alessandra Teresa Ruffatti: None declared, Chiara Infantolino: None declared, Marta Tonello: None declared, Elena Mattia: None declared, Amelia Ruffatti: None declare

Radiation hard design of HfO2 based 1T1R cells and memory arrays

In this work the electrical performance of a Rad-Hard designed 1T-1R device based on the combination of an Enclosed Layout Transistor (ELT) and a TiN/HfO2/Ti/TiN based resistor is presented for the first time. Moreover, an architectural solution for 1Mbit radiation hard RRAM array implementation is proposed

The use of anticoagulants in patients hospitalised with COVID-19

In this Cochrane Corner, we highlight the main findings of a Cochrane Review by Flumignan et al. entitled ‘Anticoagulants for people hospitalised with COVID‐19’ and discuss the implications of these findings for research and practice in South Africa. In particular, we underscore the need for additional, high‐quality, randomised controlled trials comparing different intensities of anticoagulation in patients with COVID‐19 illness. Individuals in the intensive care unit and those hospitalised with another illness who are incidentally found to be infected with SARS‐CoV‐2 should still only be treated with prophylactic‐dose low‐molecular‐weight heparin

Upgrading Therapy Strategy Improves Pregnancy Outcome in Antiphospholipid Syndrome: A Cohort Management Study

The current study evaluates the efficacy and safety of different treatment strategies for pregnant patients with antiphospholipid syndrome. One hundred twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH) + low-dose aspirin (LDA, 100 mg) (group I) and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH + LDA (group II). LMWH doses were increased throughout the pregnancies depending on the patients' weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study's primary outcome was live births. There were no significant differences in live birth rate between group I (95.4%) and group II (87.5%). Even fetal complication rate was similar in the two groups; group II nevertheless had a higher prevalence of maternal and neonatal complications (p = 0.0005 and p = 0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p = 0.0001 and p = 0.0005, respectively). Two patients in group I switched to group II therapy, six patients in group II switched to a more intensive treatment strategy (weekly plasma exchange + fortnightly intravenous immunoglobulins in addition to therapeutic LMWH + LDA). The multivariate analysis uncovered that triple antiphospholipid antibodies positivity was an independent factor leading to a more intensive therapy. All eight switched patients achieved a live birth. Study results revealed that adjusted LMWH doses and switching therapy at first signs of severe pregnancy complications led to a high rate of live births in antiphospholipid syndrome patients

Performances of a portable Fourier transform hyperspectral imaging camera for rapid investigation of paintings

Abstract: Scientific investigation in the cultural heritage field is generally aimed at the characterization of the constituent materials and the conservation status of artworks. Since the 1990s, reflectance spectral imaging proved able to map pigments, reveal hidden details and evaluate the presence of restorations in paintings. Over the past two decades, hyperspectral imaging has further improved our understanding of paints and of its changes in time. In this work, we present an innovative hyperspectral camera, based on the Fourier transform approach, utilising an ultra-stable interferometer and we describe its advantages and drawbacks with respect to the commonly used line- and spectral-scanning methods. To mitigate the weaknesses of the Fourier transform hyperspectral imaging, we propose a strategy based on the virtual extension of the dynamic range of the camera and on the design of an illumination system with a balanced emission throughout the spectral range of interest. The hyperspectral camera was employed for the analysis of a painting from the “Album of Nasir al-din Shah”. By applying analysis routines based on supervised spectral unmixing, we demonstrate the effectiveness of our camera for pigment mapping. This work shows how the proposed hyperspectral imaging camera based on the Fourier transform is a promising technique for robust and compact in situ investigation of artistic objects in conditions compatible with museum and archaeological sites. Graphic abstract: [Figure not available: see fulltext.

X-ray and Infrared Microanalyses of <i>Mona Lisa</i>'s Ground Layer and Significance Regarding Leonardo da Vinci's Palette

An exceptional microsample from the ground layer of Leonardo da Vinci's Mona Lisa was analyzed by high-angular resolution synchrotron X-ray diffraction and micro Fourier transform infrared spectroscopy, revealing a singular mixture of strongly saponified oil with high lead content and a cerussite (PbCO3)-depleted lead white pigment. The most remarkable signature in the sample is the presence of plumbonacrite (Pb5(CO3)3O(OH)2), a rare compound that is stable only in an alkaline environment. Leonardo probably endeavored to prepare a thick paint suitable for covering the wooden panel of the Mona Lisa by treating the oil with a high load of lead II oxide, PbO. The review of Leonardo's manuscripts (original and latter translation) to track the mention of PbO gives ambiguous information. Conversely, the analysis of fragments from the Last Supper confirms that not only PbO was part of Leonardo's palette, through the detection of both litharge (α-PbO) and massicot (β-PbO) but also plumbonacrite and shannonite (Pb2OCO3), the latter phase being detected for the first time in a historical painting.</p