Giant magnetoresistance and topological Hall effect in the EuGa4antiferromagnet.

We report on systematic temperature- and magnetic field-dependent studies of the EuGa4binary compound, which crystallizes in a centrosymmetric tetragonal BaAl4-type structure with space groupI4/mmm. The electronic properties of EuGa4single crystals, with an antiferromagnetic (AFM) transition atTN∼ 16.4 K, were characterized via electrical resistivity and magnetization measurements. A giant nonsaturating magnetoresistance was observed at low temperatures, reaching∼7×104% at 2 K in a magnetic field of 9 T. In the AFM state, EuGa4undergoes a series of metamagnetic transitions in an applied magnetic field, clearly manifested in its field-dependent electrical resistivity. BelowTN, in the ∼4-7 T field range, we observe also a clear hump-like anomaly in the Hall resistivity which is part of the anomalous Hall resistivity. We attribute such a hump-like feature to the topological Hall effect, usually occurring in noncentrosymmetric materials known to host topological spin textures (as e.g., magnetic skyrmions). Therefore, the family of materials with a tetragonal BaAl4-type structure, to which EuGa4and EuAl4belong, seems to comprise suitable candidates on which one can study the interplay among correlated-electron phenomena (such as charge-density wave or exotic magnetism) with topological spin textures and topologically nontrivial bands.

[Application effect of sustainable skin-stretching device in scalp and soft tissue defect].

Objective: To explore the application effect of sustainable skin-stretching device in scalp and soft tissue defect. Methods: From June 2017 to January 2020, 5 patients (3 males and 2 females, aged 31-57 (38.0±2.1) years) with large area of scalp and soft tissue defect and skull exposure were admitted to Department of Reparative and Reconstructive Surgery of the Second Hospital of Dalian Medical University. The wound area ranged from 16.0 cm×8.0 cm to 18.0 cm×12.0 cm. The sustainable skin-stretching device was installed after debridement operation for scalp wound. The wound was stretched from the 3rd day after installation of the device, at a basic speed of 1 mm/d and finished for 3 times on average. During stretching, close attention was paid to the changes in blood flow of the wound margin and the subjective feeling of the patients. When the result was negative in the squeezing and pinching test for wound margin after stretching, the further stretching was stopped, the final stretching state was maintained for 3 days, and the wounds were sutured directly. The wound healing during stretching of sustainable skin-stretching device and the occurrence of complications were observed. The rest wound areas after stretching for 5, 10, 15, and 20 days were measured. The wound healing and hair growth were observed during follow-up. Results: All the wounds of 5 patients was sutured directly after stretching for 19-23 d. There was no tension blister on the margin of wounds during stretching, and the margin of wounds healed well after being sutured without skin necrosis. After stretching treatment for 5-20 d, the wound areas were gradually decreased. During follow-up of 2-11 (4.5±1.5) months, the elasticity, color, feeling, and regenerated hair growth of the stretched scalp tissue were close to those of the surrounding normal skin tissue. The linear scar formed on the margin of wounds, but no scar formed on the wounds. Conclusions: The application of sustainable skin-stretching device can reduce the difficulty in repairing scalp and soft tissue defect, with the regenerated hair growing well after treatment, which is worthy of clinical promotion.

Detection of bcr-abl fusion mRNA in chronic myelogenous leukemia by reverse transcription polymerase chain reaction using nested primers.

Chronic myelogenous leukemia (CML) is identified by an unique t (9;22) translocation which fuses the abl gene to the breakpoint cluster region (bcr) gene. We attempted to devise a system based on the reverse transcription-polymerase chain reaction (RT-PCR) technique using nested primer, for detection of CML-specific chimeric mRNA that would provide a practical approach for molecular diagnosis of CML. In the present study, all Philadelphia chromosome (Ph1)-positive CML samples produced positive results, while the Ph1-negative acute lymphocytic leukemia (ALL) sample and samples from normal volunteers produced negative results, indicating that this method had high specificity. We constructed a sensitive and specific system for detection of CML-specific mRNA even in minute amounts of leukemic cells that expressed bcr-abl fusion mRNA in CML patient blood. This system should be useful for clinical diagnosis of CML.