In many Ni-based superalloys, dynamic strain aging (DSA) generates an inhomogeneous plastic deformation resulting in jerky flow known as the Portevin–Le Chatelier (PLC) effect. This phenomenon has a ...deleterious effect on the mechanical properties and, at high temperature, is related to the diffusion of substitutional solute atoms toward the core of dislocations. However, the question about the nature of the atomic species responsible for the PLC effect at high temperature still remains open. The goal of the present work is to answer this important question; to this purpose, three different 718-type and a 625 superalloy were studied through a nonconventional approach by mechanical spectroscopy. The internal friction (IF) spectra of all the studied alloys show a relaxation peak
P
718
(at 885 K for 0.1 Hz) in the same temperature range, 700 K to 950 K, as the observed PLC effect. The activation parameters of this relaxation peak have been measured,
E
a
(
P
718
) = 2.68 ± 0.05 eV,
τ
0
= 2·10
−15 ± 1
s as well as its broadening factor
β
= 1.1. Experiments on different alloys and the dependence of the relaxation strength on the amount of Mo attribute this relaxation to the stress-induced reorientation of Mo-Mo dipoles due to the short distance diffusion of one Mo atom by exchange with a vacancy. Then, it is concluded that Mo is the atomic species responsible for the high-temperature PLC effect in 718 superalloy.
The case of a man with diagnosis of Kikuchi-Fujimoto disease (KFD) and catastrophic antiphospholipid syndrome (CAPS) is reported. He presented prolonged fever, lymphadenopathies, arthralgia, weight ...loss, hepatosplenomegaly and positive IgM for cytomegalovirus. While he was empirically treated with tuberculostatic drugs, he suddenly developed systemic inflammatory response syndrome, multiple organ failure and distal necrosis. On suspicion of severe sepsis, antibiotics, corticoids and recombinant human activated protein C (XIGRIS®) were administrated. Exhaustive laboratory searching was negative. Histopathologic examinations of lymph node first disclosed malignant lymphoma but later KFD was confirmed. One month later, laboratory tests showed the presence of antiphospholipid antibodies (aPL). The patient was discharged after two months of hospitalization. This case exhibits a KFD complicated by definite CAPS. Cytomegalovirus could be involved in the development of both CAPS and KFD. Because of the severity of the case, we believe that XIGRIS® noticeable improved the altered coagulation profile associated with CAPS.
Highlights • Of 2288 T2 DM patient 65.7% had received the influenza vaccine in 2013. • Of 2288 T2 DM patient 19.23% had not received any influenza vaccine from 2007 to 2013. • Vaccination uptake ...increased with GP visits, number of previous influenza vaccines and duration of T2 DM. • Higher mean glycated haemoglobin was associated with a reduced probability of vaccination. • The most common reasons for refusal were the perception of not being at risk and fear of adverse reactions.
A catheter-based approach after fibrinolysis is recommended if fibrinolysis is likely to be successful in patients with acute ST-elevation myocardial infarction. We designed a 2x2 randomized, ...open-label, multicenter trial to evaluate the efficacy and safety of the paclitaxel-eluting stent and tirofiban administered after fibrinolysis but before catheterization to optimize the results of this reperfusion strategy.
We randomly assigned 436 patients with acute ST-elevation myocardial infarction to (1) bare-metal stent without tirofiban, (2) bare-metal stent with tirofiban, (3) paclitaxel-eluting stent without tirofiban, and (4) paclitaxel-eluting stent with tirofiban. All patients were initially treated with tenecteplase and enoxaparin. Tirofiban was started 120 minutes after tenecteplase in those patients randomly assigned to tirofiban. Cardiac catheterization was performed within the first 3 to 12 hours after inclusion, and stenting (randomized paclitaxel or bare stent) was applied to the culprit artery. The primary objectives were the rate of in-segment binary restenosis of paclitaxel-eluting stent compared with that of bare-metal stent and the effect of tirofiban on epicardial and myocardial flow before and after mechanical revascularization. At 12 months, in-segment binary restenosis was similar between paclitaxel-eluting stent and bare-metal stent (10.1% versus 11.3%; relative risk, 1.06; 95% confidence interval, 0.74 to 1.52; P=0.89). However, late lumen loss (0.04+/-0.055 mm versus 0.27+/-0.057 mm, P=0.003) was reduced in the paclitaxel-eluting stent group. No evidence was found of any association between the use of tirofiban and any improvement in the epicardial and myocardial perfusion. Major bleeding was observed in 6.1% of patients receiving tirofiban and in 2.7% of patients not receiving it (relative risk, 2.22; 95% confidence interval, 0.86 to 5.73; P=0.14).
This trial does not provide evidence to support the use of tirofiban after fibrinolysis to improve epicardial and myocardial perfusion. Compared with bare-metal stent, paclitaxel-eluting stent significantly reduced late loss but appeared not to reduce in-segment binary restenosis.
URL: http://clinicaltrials.gov. Unique identifier: NCT00306228.
Subacute thyroiditis (SAT) is an inflammatory disorder of the thyroid gland that causes destructive thyrotoxicosis and is attributed to a viral or post-viral response. SARS-CoV-2 is a novel ...coronavirus that caused a global pandemic in 2020. We present a case that suggests that there may be a relationship between SAT and corona-virus disease 2019 (COVID-19).
We describe the clinical findings, thyroid function tests, and neck ultrasound of a patient presenting with anterior neck pain.
A 47-year-old, Filipino female presented with anterior neck pain associated with neck tenderness and goiter. She did not have fever or respiratory symptoms but had right lower lobe pneumonia on chest radiograph. Thyroid function tests were consistent with subclinical hyperthyroidism with thyroid-stimulating hormone of 0.05 μIU/mL (reference range is 0.47 to 4.68 μIU/mL), free thyroxine of 1.68 pg/mL (reference range is 0.78 to 2.19 pg/mL), and total triiodothyronine of 1.4 ng/mL (reference range is 0.97 to 1.69 ng/mL). Anti-thyroid peroxidase, anti-thyroglobulin, and thyroid-stimulating hormone receptor antibodies were negative. Neck ultrasound showed heterogenous thyroid tissues with normal vascularity. Reverse transcription-polymerase chain reaction for SARS-CoV-2 using nasopharyngeal and oropharyngeal swabs were positive. The patient was diagnosed as having SAT and was treated with mefenamic acid, which was later switched to celecoxib. Ceftriaxone and hydroxychloroquine were started for COVID-19 pneumonia. Complete resolution of symptoms and primary hypothyroidism occurred after 2 months.
SAT may be a presenting symptom or a sequela of COVID-19. Histopathology studies and definitive documentation of the virus in thyroid tissues may be required to confirm the relationship between SAT and COVID-19.
Among the different families of shape memory alloys (SMA), the Fe-Mn-Si-Cr-Ni alloys have attracted a renewed interest because of its low cost, high corrosion resistance and high recovery strength ...during the shape memory effect, and the new technologies of additive manufacturing offer unforeseen possibilities for this family of SMA. In the present work, the reversible γ − ε martensitic transformation (MT), responsible for the shape memory effect, is studied in two Fe-Mn-Si-Cr-Ni alloys with high (20.2 wt%) and low (15.8 wt%) Mn content, produced by the conventional route of casting and rolling, in comparison with the MT in another similar alloy, with intermediate Mn content (19.4 wt%), which was produced by gas atomization and additive manufacturing through laser metal deposition. The forward and reverse γ − ε MT is studied by mechanical spectroscopy through the internal friction spectra and the dynamic modulus variation, together with a parallel microstructural characterization including in-situ observation of the γ − ε MT during cooling and heating at the scanning electron microscope. The evolution of the transformed fraction of ε martensite, evaluated through the integral area of the internal friction peak, was followed along thermal cycling in all three alloys. Both, the internal friction and the electron microscopy studies show that the ε martensite amount increases very fast during the first few cycles, and then decreases with a tendency towards its stabilization for many tens of cycles. The results show that the γ − ε MT is more stable on cycling in the additive manufactured sample than in the conventionally processed samples, opening new avenues for designing shape memory steels to be specifically processed through additive manufacturing.
•Reversible martensitic transformation in shape memory steels.•Shape memory steels produced by additive manufacturing.•Internal friction reveals good shape memory in additive manufactured steels.•Shape memory stainless steel produced by laser metal deposition.•Shape memory steels characterized by mechanical spectroscopy.
IntroductionCardiac adipose tissue is a source of progenitor cells with regenerative capacity. Studies in rodents demonstrated that the intramyocardial delivery of cells derived from this tissue ...improves cardiac function after myocardial infarction (MI). We developed a new reparative approach for damaged myocardium that integrates the regenerative properties of cardiac adipose tissue with tissue engineering. In the adipose graft transposition procedure (AGTP), we dissect a vascularised flap of autologous pericardial adipose tissue and position it over the myocardial scarred area. Following encouraging results in acute and chronic MI porcine models, we performed the clinical trial (NCT01473433, AdiFLAP trial) to evaluate safety in patients with chronic MI undergoing coronary artery bypass graft. The good safety profile and trends in efficacy warranted a larger trial.Study designThe AGTP II trial (NCT02798276) is an investigator initiated, prospective, randomised, controlled, multicentre study to assess the efficacy of the AGTP in 108 patients with non-revascularisable MI. Patients will be assigned to standard clinical practice or the AGTP. The primary endpoint is change in necrotic mass ratio by gadolinium enhancement at 91 and 365 days. Secondary endpoints include improvement in regional contractibility by MRI at 91 and 365 days; changes in functional MRI parameters (left ventricular ejection fraction, left and right ventricular geometric remodelling) at 91 and 365 days; levels of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) at 7, 91 and 365 days; appearance of arrhythmias from 24 hour Holter monitoring at 24 hours, and at 91 and 365 days; all cause death or re-hospitalisation at 365 days; and cardiovascular death or re-hospitalisation at 365 days.Ethics and disseminationThe institutional review board approved the trial which will comply with the Declaration of Helsinki. All patients will provide informed consent. It may offer a novel, effective and technically simple technique for patients with no other therapeutic options. The results will be submitted to indexed medical journals and national and international meetings.Trial registration numberClinicalTrials.gov: NCT02798276, pre-results.
The martensitic transformation temperatures and the types of martensitic phases have been determined in a wide concentration range of technological interest for Cu-Al-Ni shape-memory alloys (SMAs) A ...stability diagram of martensitic phases as a function of alloy concentration has been determined. It is found that when the aluminum content increases, the transformation changes from beta sub 3 - > beta ' sub 3 to beta sub 3 - > gamma ' sub 3 , with an intermediate concentration range where both martensites coexist due to a beta sub 3 - > gamma ' sub 3 + beta ' sub 3 transformation. On the other hand, an increase of nickel content stabilizes the martensite beta ' sub 3 , changing from a mixed beta sub 3 - > gamma ' sub 3 + beta ' sub 3 to a single beta sub 3 - > beta ' sub 3 transformation. Furthermore, linear relationships between M sub s and Al and Ni concentrations have been obtained for all types of martensitic phases.
The influence of precipitation processes on the characteristics of the martensitic transformation in two Cu–Al–Ni shape memory alloys processed by powder metallurgy has been analyzed. The ...Cu–14.37Al–4.2Ni (wt.%) alloy with a hypereutectoid composition undergoes a low-temperature martensitic transformation,
M
s
<
100
°C. On the other hand, the Cu–14.15Al–3.25Ni (wt.%) near eutectoid composition undergoes a high-temperature martensitic transformation,
M
s
>
110
°C. The evolution of the kind of induced martensite, hysteresis and transformation temperatures as a function of thermal history has been studied by differential scanning calorimetry. Also, resonant ultrasound spectroscopy allows changes to be monitored of elastic constants during the evolution of the microstructure. Finally, a comparative analysis of the behavior of both alloys has been made.
Smoldering myeloma is an asymptomatic plasma cell dyscrasia with a heterogeneous propensity to progress to active myeloma. In order to investigate the biology of smoldering myeloma patients with high ...risk of progression, we analyzed the genomic characteristics by FISH, SNP-arrays and gene expression profile of a group of patients with high-risk smoldering myeloma included in a multicenter randomized trial. Chromosomal abnormalities detected by FISH and SNP-arrays at diagnosis were not associated to risk of progression to symptomatic myeloma. However, the overexpression of four SNORD genes (SNORD25, SNORD27, SNORD30 and SNORD31) was correlated with shorter time to progression (P<0.03). When plasma cells from high-risk smoldering patients who progressed to symptomatic myeloma were sequentially analyzed, newly acquired lesions together with an increase in the proportion of plasma cells carrying a given abnormality were observed. These findings suggest that gene expression profiling is a valuable technique to identify smoldering myeloma patients with high risk of progression. (Clinical Trials NCT00443235).
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