Background and Aims: Severe acute respiratory syndrome (SARS) is a virulent viral infection that affects a number of organs and systems. This study examined if SARS may result in cardiovascular ...complications. Methods and Results: 121 patients (37.5 (SD13.2) years, 36% male) diagnosed to have SARS were assessed continuously for blood pressure, pulse, and temperature during their stay in hopsital. Hypotension occurred in 61 (50.4%) patients in hospital, and was found in 28.1%, 21.5%, and 14.8% of patients during the first, second, and third week, respectively. Only one patient who had transient echocardiographic evidence of impaired left ventricular systolic function required temporary inotropic support. Tachycardia was present in 87 (71.9%) patients, and was found in 62.8%, 45.4%, and 35.5% of patients from the first to third week. It occurred independent of hypotension, and could not be explained by the presence of fever. Tachycardia was also present in 38.8% of patients at follow up. Bradycardia only occurred in 18 (14.9%) patients as a transient event. Reversible cardiomegaly was reported in 13 (10.7%) patients, but without clinical evidence of heart failure. Transient atrial fibrillation was present in one patient. Corticosteroid therapy was weakly associated with tachycardia during the second (χ2 = 3.99, p = 0.046) and third week (χ2 = 6.53, p = 0.01), although it could not explain tachycardia during follow up. Conclusions: In patients with SARS, cardiovascular complications including hypotension and tachycardia were common but usually self limiting. Bradycardia and cardiomegaly were less common, while cardiac arrhythmia was rare. However, only tachycardia persisted even when corticosteroid therapy was withdrawn.
We present X-ray timing results of the new black hole candidate MAXI J1535−571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight-HXMT) observations taken from 2017 September 6 to ...23. Following the definitions given by Belloni, we find that the source exhibits transitions from the low/hard state to the hard intermediate state, and eventually to the soft intermediate state. Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV, which has rarely been explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lag) and strongly correlated with the centroid frequency. Assuming a geometrical origin of type-C QPOs, the source is consistent with being a high-inclination system.
New Fe82-85B13-16Si1Cu1 amorphous alloys with low B content and high B/Si content ratios were synthesized by melt spinning for developing good soft magnetic and high strength materials. The ...crystallization occurs through two stages and the first-stage onset temperature increases from 673 K to 705 K with increasing B content, while the second-stage temperature remains nearly constant. The first and second stages are due to the precipitation of the α-Fe(Si) phase with a size of about 30 nm and the decomposition of the remaining amorphous phase to α-Fe(Si)+Fe3B+Fe2B, respectively. The Fe-based alloys exhibited good soft magnetic properties both in annealed amorphous and nanocrystallized amorphous+α-Fe(Si) phases. The saturated magnetic flux density, coercivity and permeability at 1 kHz are 1.7 T, 4.92 A/m and 7100, respectively, for the annealed amorphous 14B alloy and 1.74 T, 5.62 A/m and 10100, respectively, for the nanocrystallized 13B alloy. The Vickers hardness (Hv) is 803–867 for the as-spun state and it increases with decreasing B content. The Hv increases significantly by crystallization to α-Fe+amorphous phases and reaches 997–1550 for the alloys annealed at 693–763 K just before Tx2. The ultrahigh Hv is presumably due to the combination of fine nanoscale mixed phases, high volume fraction of α-Fe(Si) without internal defects and the enrichment of B into the remaining amorphous phase. Such ultrahigh Hv has not been obtained for Fe-based amorphous and crystallized alloys before and the addition of 1%Cu is essential for the ultrahigh Hv and the amorphous phase formation for the Fe-rich 85%Fe alloy. The new Fe-based alloys are encouraging as future soft magnetic and ultrahigh strength materials with low material cost.
•New Fe82-85B13-16Si1Cu1 amorphous alloys with high B/Si ratios were synthesized.•The Bs, Hc and μ at 1 kHz are 1.74 T, 5.62 A/m and 10100 for the annealed 13%B alloy.•The Vickers hardness increases significantly by annealing and reaches 997–1550.•The addition of 1%Cu is essential for the ultrahigh hardness for the 13%B alloy.
In this prospective cross-sectional study on young premenopausal breast cancer patients, the objectives were to: determine the incidences of chemotherapy-related amenorrhea (CRA) and menopause (CRM); ...identify associated factors; and assess plasma levels of estradiol (E2) and follicular stimulating hormone (FSH) among patients who developed menopause.
Eligibility criteria include Chinese stage I-III breast cancer patients, premenopausal, age ≤45 at breast cancer diagnosis, having received adjuvant chemotherapy, within 3-10 years after breast cancer diagnosis. Detailed menstrual history prior to and after adjuvant treatment was taken at study entry. Patients' background demographics, tumor characteristics and anti-cancer treatments were collected. The rates of CRA and CRM were determined. Analysis was conducted to identify factors associated with CRM. For postmenopausal patients, levels of E2 and FSH were analyzed.
286 patients were recruited; the median time from breast cancer diagnosis to study entry was 5.0 years. 255 patients (91.1%) developed CRA. Of these, 66.7% regained menstruation. At the time of study entry, 137 (48.9%) had developed CRM, amongst whom 84 were age ≤45. On multivariate analysis, age was the only associated factor. Among patients with CRM, the median FSH was 41.0 IU/L; this was significantly lower in those who were taking tamoxifen compared to those who were not (20.1 vs. 59.7 IU/L, p<0.0001). The E2 level was <40 pmol/L; there was no difference between those who were still on tamoxifen or not.
After adjuvant chemotherapy, the majority of young Chinese breast cancer patients developed CRA; ~50% developed CRM, with 61% at age ≤45. Age at diagnosis is the only factor associated with CRM. FSH level may be affected by tamoxifen intake.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
► Microstructure and tensile properties are investigated systematically. ► The TiB and TiC tended to segregate at prior β grain boundaries. ► The prior β grain size and α lath width are significantly ...refined. ► Microstructural refinement donminates the strengthening contribution.
In this paper, high temperature titanium matrix composites with different volume fraction of (TiB+TiC) reinforcements were in situ synthesized by casting route. The microstructure and tensile properties of the composites were presented and discussed. The results reveal that both the TiB whiskers and TiC particles tend to segregate at prior β boundaries. The prior β grain size and α lath width are gradually refined with increasing volume fraction of reinforcements. Evolution of tensile properties shows that enhancement in yield strength and ultimate tensile strength with addition of reinforcements is primarily attributed to microstructural refinement, while the remarkable reduction in ductility is possibly due to the cracking of TiB whiskers and TiC particles.
Extremely high saturated magnetization (Bs) of 1.92 T in conjunction with low coercivity (Hc) of 2 A/m was found to be achieved for (Fe0.8Co0.2)85B14Si1 amorphous alloy. The high Bs above 1.9 T was ...the first evidence for amorphous alloys. The slight increase of B to 15%B reduces Bs to 1.88 T. The high Bs of 1.92 T is much higher than that (1.63 T) for the new commercial Fe-B-Si-C amorphous alloy and comparable to commercial Fe-Si steels. The excellent soft magnetic properties, which cannot be obtained for all soft magnetic alloys including amorphous, nanocrystalline and crystalline alloys reported to date, were obtained by annealing the as-spun amorphous alloy ribbon for 600 s at 593 K in a magnetic field of 15.9 kA/m. The high Bs above 1.9 T was obtained in a rather wide annealing conditions of 543–603 K and 300–1200 s, indicating the ease of achieving the excellent soft magnetic properties. No appreciable crystalline phase is recognized in the annealed ribbon even by HRTEM and electron diffraction pattern. The effective permeability at 1 kHz also exhibits high values above 20000 and the Curie temperature also shows high values above the onset temperature of crystallization corresponding to high thermal stability of soft magnetic properties. Besides, the (Fe0.8Co0.2)84B15Si1 and (Fe0.8Co0.2)85B14Si1 amorphous alloys exhibit good bending ductility even in the optimal annealed state. The corrosion resistance in 3.5 mass% NaCl aqueous solution is better than that for the commercial Fe-Si-B-C amorphous alloy. The first synthesis of the Fe-based amorphous alloy having simultaneously high Bs above 1.9 T, low Hc of about 2 A/m, high effective permeability, high Tc and good bending ductility is promising for future extension of amorphous alloys as engineering soft magnetic materials.
•(Fe0.8Co0.2)85B14Si1 alloy exhibits high Bs above 1.9 T, low Hc of 2.2 A/m and high μe.•This amorphous alloy exhibits high thermal stability of soft magnetic properties.•This amorphous alloy exhibits good bending ductility and corrosion resistance.
The formation, thermal stability and mechanical properties of high entropy (HE) (Fe0.25Co0.25Ni0.25Cr0.125Mo0.125)100-xBx (x = 11–31 at%) amorphous alloys were examined with the aim of clarifying the ...partial replacement effect of Cr by Mo in comparison with previously reported HE (Fe0.25Co0.25Ni0.25Cr0.25)100-xBx amorphous alloys. The amorphous phase was formed in a very wide B range of 11–31 at%, and crystallization temperature (Tx) and Vickers hardness (Hv) increased with increasing B content. The peak position of the X-ray diffraction patterns shifts to the higher diffraction angle side with increasing B content, implying the development of denser coordinated atomic configuration. There is a good linear relation between Hv and the angle shift of the peak position in the broad diffraction pattern. The crystallization mode changes from Am → fcc + Am for the 15–20 at% B alloys to Am → glass transition (GT) →M23B6 for the 25 and 27 at% B alloys. It is noticed that the GT is observed for the alloys with 22–31 at% B. The good bending ductility is obtained for the alloys up to 25 at% B and the ductile 25 at% B alloy exhibits high Tx and high Hv. Considering the previous data that the Mo-free amorphous alloys are formed in the limited B range of 18–22 at% B and do not show the GT, the partial replacement of Cr by Mo is effective for the increase in glass-forming ability and Hv through the development of more coordinated atomic configuration resulting from the increase in the level of satisfaction of the three component rules for stabilization of supercooled liquid. The interpretation is also supported from the differences in the calculated entropy parameters between the HE amorphous alloys and HE crystalline solid solution alloys. The first formation of an amorphous phase for the lower and higher B content alloys of 11–14 and 26–31 at% is also promising for future application to structural materials.
•High entropy (FeCoNiCrMo)100-xBx (x = 11–31 at%) amorphous alloys were studied.•Partial replacing Cr by Mo increases glass-forming ability and Vickers hardness.•Formation of amorphous phase with large B range is promising for future application.
Extremely good soft magnetic properties of high saturation magnetization (Bs) above 1.8 T and low coercivity (Hc) below 5 A/m were obtained for (Fe1-xCox)83B16Si1 (x = 0.1–0.3) amorphous ribbons ...annealed at the temperature between Tx1-120 K and Tx1-40 K. Here Tx1 is the onset temperature of the first exothermic crystallization peak. The best characteristics were 1.86 T for Bs and 3 A/m for Hc at x = 0.2. There are no previous data on the melt-spun alloys with high Bs above 1.8 T and low Hc below 5 A/m and hence the present amorphous alloys are regarded as a novel good soft magnetic alloy with high Bs comparable to Fe-Si steels. Curie temperature (Tc) of the x = 0.2 alloy was above Tx1 (708 K), implying high thermal stability of magnetic characteristics. The saturated magnetostriction for x = 0.2 was about 32 ppm and the effective permeability at 1 kHz showed as high as 1.6 × 104. The high Bs can be attributed to the low metalloid content containing mainly B element which suppresses effectively the reductions of Bs and Tc among metalloid elements, as well as the optimum Co/Fe content ratio with the maximum magnetic interaction in conjunction with maximum atomic volume. Moreover, these alloy ribbons exhibited good bending ductility even after optimum annealing treatment, in addition to high Vickers hardness of about 1000 and improved corrosion resistance comparing with the corresponding Co-free alloy. The excellent soft magnetic amorphous alloys are promising for further extension as engineering soft magnetic materials.
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•Amorphous (Fe0.8Co0.2)83Si1B16 alloy shows high Bs of 1.86 T and low Hc of 3 A/m.•The annealed alloys keep good bending ductility and high Vickers hardness.•The Tc of alloy is higher than its Tx1, and Bs shows high thermal stability.
We examined high entropy (HE) effect on the formation, structure, thermal stability, mechanical properties and corrosion behavior for (Fe,Co,Ni,Cr)100-xBx (x = 18–26) amorphous alloys in comparison ...with Fe100-xBx amorphous alloys. The as-quenched structure consists of an amorphous single phase for the 18–24%B alloys, and amorphous + tetragonal Cr5B3 phases for the 26%B alloy. The broad diffraction peak position due to amorphous phase shifts to a higher wave vector side with increasing B content for the HE alloys, while that of the Fe-B alloys changes to the lower wave vector side, indicating the distinct difference in disordered atomic structure between the HE alloys and the binary alloys. All the as-spun HEA ribbons exhibit good bending ductility in spite of the coexistence with their crystalline phases, being different from the brittle nature for the 26%B binary alloy. The crystallization temperature (Tx) and Vickers hardness (Hv) increase with increasing B content, show maximum values of 803 K and 1130, respectively, at 22%B and then decrease to 793 K and 1070, respectively at 26%B, being different from the nearly constant Tx and almost linear increase in Hv with increasing B content for the Fe100-xBx alloys. The corrosion resistance in NaCl, H2SO4 and HCl solutions evaluated by potential and anode current density is much better for the HE alloys as compared with the Fe-B alloys. Thus, the Tx, Hv, bending ductility and corrosion resistance for the HE amorphous alloys containing more than 20 at%B are much superior to those for the Fe-B amorphous alloys. The fully crystallized structure consists of fcc + FeB + Fe2B + Cr5B3 phase for the HE 22–26 at%B alloys and bcc-Fe + Fe2B for the Fe-B alloys. The significant improvement of the fundamental properties caused by the HE component modification is presumably due to the formation of Cr-B pair with higher B-rich components. The improved properties in conjunction with the change in the disordered structure for the HE amorphous alloys provide an opportunity of developing a new functional material by alloy design to HE type compositions.
•Control and design of spontaneous generation of inhomogeneity of alloy components and atomic configurations.•The high entropy alloys exhibit good bending ductility over the whole B range.•The Hv of the high entropy alloys shows a maximum of 1130 at 20 at%B.•The corrosion resistance in NaCl, H2SO4 and HCl solutions is significantly enhanced.
Abstract
We report on analysis of observations of the bright transient X-ray pulsar Swift J0243.6+6124 obtained during its 2017-2018 giant outburst with Insight-HXMT, NuSTAR, and Swift observatories. ...We focus on the discovery of a sharp state transition of the timing and spectral properties of the source at super-Eddington accretion rates, which we associate with the transition of the accretion disk to a radiation pressure dominated (RPD) state, the first ever directly observed for magnetized neutron star. This transition occurs at slightly higher luminosity compared to already reported transition of the source from sub- to super-critical accretion regime associate with onset of an accretion column. We argue that this scenario can only be realized for comparatively weakly magnetized neutron star, not dissimilar to other ultra-luminous X-ray pulsars (ULPs), which accrete at similar rates. Further evidence for this conclusion is provided by the non-detection of the transition to the propeller state in quiescence which strongly implies compact magnetosphere and thus rules out magnetar-like fields.
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