125 research outputs found

    Ultrafast giant magnetic cooling effect in ferromagnetic Co/Pt multilayers

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    The magnetic cooling effect originates from a large change in entropy by the forced magnetization alignment, which has long been considered to be utilized as an alternative environment-friendly cooling technology compared to conventional refrigeration. However, an ultimate timescale of the magnetic cooling effect has never been studied yet. Here, we report that a giant magnetic cooling (up to 200 K) phenomenon exists in the Co/Pt nanomultilayers on a femtosecond timescale during the photoinduced demagnetization and remagnetization, where the disordered spins are more rapidly aligned, and thus magnetically cooled, by the external magnetic field via the lattice-spin interaction in the multilayer system. These findings were obtained by the extensive analysis of time-resolved magneto-optical responses with systematic variation of laser fluence as well as external field strength and direction. Ultrafast giant magnetic cooling observed in the present study can enable a new avenue to the realization of ultrafast magnetic devices.111Ysciescopu

    Traumatic neuroma of the right posterior hepatic duct with an anatomic variation masquerading as malignancy: a case report

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    Traumatic neuroma (TN), also known as amputation neuroma, is a reactive hyperplasia of nerve fibers and connective tissue arising from Schwann cells after trauma or surgery. TN of the bile duct is usually asymptomatic, but rarely can lead to right upper quadrant pain, biliary obstruction, and acute cholangitis. It is very difficult to discriminate TN from malignancy before surgery, although doing so could avoid an unnecessary radical resection of the lesion. In the course of surgery, TN can be caused by unintentional injury of a nerve fiber near the common bile duct (CBD) and heat damage to an artery, complete ligation of an artery, and excessive manipulation of the CBD. Therefore, to prevent TN after cholecystectomy, surgery should be performed carefully with appropriate consideration of anatomic variations, and a cystic duct should not be resected too close to the CBD. The possibility of TN should be considered if a patient who has undergone CBD resection with hepaticojejunostomy or cholecystectomy long ago experiences symptoms of jaundice, cholangitis, or obliteration of the CBD. In this report, we present a case of TN mimicking cholangiocarcinoma that emerged from a cystic duct stump after cholecystectomy

    Outcomes of Lung Transplantation in Patients With Right Ventricular Dysfunction: A Single-Center Retrospective Analysis Comparing ECMO Configurations in a Bridge-to-Transplant Setting

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    This study aimed to assess the lung transplantation (LT) outcomes of patients with right ventricular dysfunction (RVD), focusing on the impact of various extracorporeal membrane oxygenation (ECMO) configurations. We included adult patients who underwent LT with ECMO as a bridge-to-transplant from 2011 to 2021 at a single center. Among patients with RVD (n = 67), veno-venous (V-V) ECMO was initially applied in 79% (53/67) and maintained until LT in 52% (35/67). Due to the worsening of RVD, the configuration was changed from V-V ECMO to veno-arterial (V-A) ECMO or a right ventricular assist device with an oxygenator (Oxy-RVAD) in 34% (18/67). They showed that lactic acid levels (2–6.1 mmol/L) and vasoactive inotropic score (6.6–22.6) increased. V-A ECMO or Oxy-RVAD was initiated and maintained until LT in 21% (14/67) of cases. There was no significant difference in the survival rates among the three configuration groups (V-V ECMO vs. configuration changed vs. V-A ECMO/Oxy-RVAD). Our findings suggest that the choice of ECMO configuration for LT candidates with RVD should be determined by the patient’s current hemodynamic status. Vital sign stability supports the use of V-V ECMO, while increasing lactic acid levels and vasopressor needs may require a switch to V-A ECMO or Oxy-RVAD

    Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films

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    We report a universal terahertz (THz) emission behavior from simple Ni, Fe, and Co metallic ferromagnetic films, triggered by the femtosecond laser pulse and subsequent photoinduced demagnetization on an ultrafast time scale. THz emission behavior in ferromagnetic films is found to be consistent with initial magnetization states controlled by external fields, where the hysteresis of the maximal THz emission signal is observed to be well-matched with the magnetic hysteresis curve. It is experimentally demonstrated that the ultrafast THz emission by the photoinduced demagnetization is controllable in a simple way by external fields as well as pump fluences. © 2020, The Author(s).1
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