The technique of Brillouin light scattering is used to observe strong excitation of magnons in an... more The technique of Brillouin light scattering is used to observe strong excitation of magnons in antiferromagnetically coupled trilayers of Fe/Cr/Fe at room temperature. The magnons are driven out of equilibrium by a microwave current applied in the trilayer through point contacts. The magnitude of the scattering intensity is investigated as a function of the magnon wave number and applied magnetic field. Confirming recent theoretical predictions, the observations provide strong evidence of electronic spin injection in the rf driving field.
Ferromagnetic resonance has been used to study the room-temperature linewidth and frequency shift... more Ferromagnetic resonance has been used to study the room-temperature linewidth and frequency shift of the q=0 spin-wave mode in thin films of NiFe sputtered on Si(100) substrates. The data on the variation of the linewidth and resonance field with film thickness are completely ...
A microwave-pumped spin-wave-instability experiment is used to demonstrate that chaos can be cont... more A microwave-pumped spin-wave-instability experiment is used to demonstrate that chaos can be controlled by a small periodic perturbation of an available system parameter, as recently proposed by Ott, Grebogi, and Yorke. The experiment is performed in an yttrium-iron-garnet sphere ...
A spin-wave theory is presented for the magnetization dynamics in a ferromagnetic film that is tr... more A spin-wave theory is presented for the magnetization dynamics in a ferromagnetic film that is traversed by spin-polarized carriers at high direct-current densities. It is shown that nonlinear effects due to four-magnon interactions arising from dipolar and surface anisotropy energies limit the growth of the driven spin wave and produce shifts in the microwave frequency oscillations. The theory explains quantitatively recent experimental results in nanometric point contacts onto magnetic multilayers showing downward frequency shifts (redshifts) with increasing current, if the external field is on the film plane, and upward shifts (blueshifts), if the field is perpendicular to the film.
New strategies to increase coronary patency rate before primary angioplasty are under discussion.... more New strategies to increase coronary patency rate before primary angioplasty are under discussion. We tested the hypothesis that use of a high dose of a standard heparin bolus could achieve an acceptable rate of re-opening occluded infarct-related arteries thus providing an alternative to chemical thrombolysis before admission of the patient to hospital, and a pretreatment for primary angioplasty. Forty-eight patients who presented within 12 h of acute myocardial infarction with ST segment elevation were assigned randomly to groups to receive aspirin (200 mg orally) and high-dose standard heparin 300 U/kg as an intravenous bolus (n = 25), or aspirin and placebo bolus (n = 23). Thereafter, all patients underwent coronary arteriography to assess their suitability for primary angioplasty. The high-dose heparin group had greater patency rate (Thrombolysis in Myocardial Infarction grade 2 or 3 flow in the infarct-related artery) than the placebo group (52% compared with 13%, P = 0.006). Hemorrhages related to the puncture site that required blood transfusion occurred in two of 25 and in one of 23 patients in the high-dose heparin and placebo groups, respectively. Our study suggests that high-dose standard heparin does have a thrombolytic action when administered as an intravenous bolus.
New strategies to increase coronary patency rate before primary angioplasty are under discussion.... more New strategies to increase coronary patency rate before primary angioplasty are under discussion. We tested the hypothesis that use of a high dose of a standard heparin bolus could achieve an acceptable rate of re-opening occluded infarct-related arteries thus providing an alternative to chemical thrombolysis before admission of the patient to hospital, and a pretreatment for primary angioplasty. Forty-eight patients who presented within 12 h of acute myocardial infarction with ST segment elevation were assigned randomly to groups to receive aspirin (200 mg orally) and high-dose standard heparin 300 U/kg as an intravenous bolus (n = 25), or aspirin and placebo bolus (n = 23). Thereafter, all patients underwent coronary arteriography to assess their suitability for primary angioplasty. The high-dose heparin group had greater patency rate (Thrombolysis in Myocardial Infarction grade 2 or 3 flow in the infarct-related artery) than the placebo group (52% compared with 13%, P = 0.006). Hemorrhages related to the puncture site that required blood transfusion occurred in two of 25 and in one of 23 patients in the high-dose heparin and placebo groups, respectively. Our study suggests that high-dose standard heparin does have a thrombolytic action when administered as an intravenous bolus.
The technique of Brillouin light scattering is used to observe strong excitation of magnons in an... more The technique of Brillouin light scattering is used to observe strong excitation of magnons in antiferromagnetically coupled trilayers of Fe/Cr/Fe at room temperature. The magnons are driven out of equilibrium by a microwave current applied in the trilayer through point contacts. The magnitude of the scattering intensity is investigated as a function of the magnon wave number and applied magnetic field. Confirming recent theoretical predictions, the observations provide strong evidence of electronic spin injection in the rf driving field.
Ferromagnetic resonance has been used to study the room-temperature linewidth and frequency shift... more Ferromagnetic resonance has been used to study the room-temperature linewidth and frequency shift of the q=0 spin-wave mode in thin films of NiFe sputtered on Si(100) substrates. The data on the variation of the linewidth and resonance field with film thickness are completely ...
A microwave-pumped spin-wave-instability experiment is used to demonstrate that chaos can be cont... more A microwave-pumped spin-wave-instability experiment is used to demonstrate that chaos can be controlled by a small periodic perturbation of an available system parameter, as recently proposed by Ott, Grebogi, and Yorke. The experiment is performed in an yttrium-iron-garnet sphere ...
A spin-wave theory is presented for the magnetization dynamics in a ferromagnetic film that is tr... more A spin-wave theory is presented for the magnetization dynamics in a ferromagnetic film that is traversed by spin-polarized carriers at high direct-current densities. It is shown that nonlinear effects due to four-magnon interactions arising from dipolar and surface anisotropy energies limit the growth of the driven spin wave and produce shifts in the microwave frequency oscillations. The theory explains quantitatively recent experimental results in nanometric point contacts onto magnetic multilayers showing downward frequency shifts (redshifts) with increasing current, if the external field is on the film plane, and upward shifts (blueshifts), if the field is perpendicular to the film.
New strategies to increase coronary patency rate before primary angioplasty are under discussion.... more New strategies to increase coronary patency rate before primary angioplasty are under discussion. We tested the hypothesis that use of a high dose of a standard heparin bolus could achieve an acceptable rate of re-opening occluded infarct-related arteries thus providing an alternative to chemical thrombolysis before admission of the patient to hospital, and a pretreatment for primary angioplasty. Forty-eight patients who presented within 12 h of acute myocardial infarction with ST segment elevation were assigned randomly to groups to receive aspirin (200 mg orally) and high-dose standard heparin 300 U/kg as an intravenous bolus (n = 25), or aspirin and placebo bolus (n = 23). Thereafter, all patients underwent coronary arteriography to assess their suitability for primary angioplasty. The high-dose heparin group had greater patency rate (Thrombolysis in Myocardial Infarction grade 2 or 3 flow in the infarct-related artery) than the placebo group (52% compared with 13%, P = 0.006). Hemorrhages related to the puncture site that required blood transfusion occurred in two of 25 and in one of 23 patients in the high-dose heparin and placebo groups, respectively. Our study suggests that high-dose standard heparin does have a thrombolytic action when administered as an intravenous bolus.
New strategies to increase coronary patency rate before primary angioplasty are under discussion.... more New strategies to increase coronary patency rate before primary angioplasty are under discussion. We tested the hypothesis that use of a high dose of a standard heparin bolus could achieve an acceptable rate of re-opening occluded infarct-related arteries thus providing an alternative to chemical thrombolysis before admission of the patient to hospital, and a pretreatment for primary angioplasty. Forty-eight patients who presented within 12 h of acute myocardial infarction with ST segment elevation were assigned randomly to groups to receive aspirin (200 mg orally) and high-dose standard heparin 300 U/kg as an intravenous bolus (n = 25), or aspirin and placebo bolus (n = 23). Thereafter, all patients underwent coronary arteriography to assess their suitability for primary angioplasty. The high-dose heparin group had greater patency rate (Thrombolysis in Myocardial Infarction grade 2 or 3 flow in the infarct-related artery) than the placebo group (52% compared with 13%, P = 0.006). Hemorrhages related to the puncture site that required blood transfusion occurred in two of 25 and in one of 23 patients in the high-dose heparin and placebo groups, respectively. Our study suggests that high-dose standard heparin does have a thrombolytic action when administered as an intravenous bolus.
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