Daily VMA (vanillyl mandelic acid) variation in urine in relation of fatigue sensation, stress and life stile of nurses on night shift.

Daily VMA variation in urine in relation of fatigue sensation, stress and life stile of nurses on night shift. To evaluate exhaustion objectively in hospital nurses, daily variation of urinaly VMA (vanillyl mandelic acid) excretion was measured in hospital nurses working in daytime and nighttime and it's correlation with the data from Psychological Stress Response Scale (PSRS) test, the burn-out scale, quality and quantity of sleep and daily life stile recorded throughout 24 hours were studied. VMA level in urine showed circadian rhythmic movement, higher in daytime and lower in nighttime. During night shift, VMA in urine in nighttime showed slightly higher level than during day shift but in the subsequent daytime after night shift, VMA level was stillkeeping normal circadian rhythm, resuling flatness of daily fluctuation of VMA level. Dissatisfaction of sleep during daily fluctation of VMA level. Dissatisfaction of sleep during daytime was noticed. Correlation between VMA level in urine and sense of tiredness, stresses or burn-out scale were not carfied in this study because of shortage of samples but working conditions might affect biologicalresponse of exhaustion

Natural van der Waals heterostructural single crystals with both magnetic and topological properties

Heterostructures having both magnetism and topology are promising materials for the realization of exotic topological quantum states while challenging in synthesis and engineering. Here, we report natural magnetic van der Waals heterostructures of (MnBi2Te4)m(Bi2Te3)n that exhibit controllable magnetic properties while maintaining their topological surface states. The interlayer antiferromagnetic exchange coupling is gradually weakened as the separation of magnetic layers increases, and an anomalous Hall effect that is well coupled with magnetization and shows ferromagnetic hysteresis was observed below 5 K. The obtained homogeneous heterostructure with atomically sharp interface and intrinsic magnetic properties will be an ideal platform for studying the quantum anomalous Hall effect, axion insulator states, and the topological magnetoelectric effect.Comment: 40 pages, 15 figure

Kondo effect in coupled quantum dots: a Non-crossing approximation study

The out-of-equilibrium transport properties of a double quantum dot system in the Kondo regime are studied theoretically by means of a two-impurity Anderson Hamiltonian with inter-impurity hopping. The Hamiltonian, formulated in slave-boson language, is solved by means of a generalization of the non-crossing approximation (NCA) to the present problem. We provide benchmark calculations of the predictions of the NCA for the linear and nonlinear transport properties of coupled quantum dots in the Kondo regime. We give a series of predictions that can be observed experimentally in linear and nonlinear transport measurements through coupled quantum dots. Importantly, it is demonstrated that measurements of the differential conductance ${\cal G}=dI/dV$, for the appropriate values of voltages and inter-dot tunneling couplings, can give a direct observation of the coherent superposition between the many-body Kondo states of each dot. This coherence can be also detected in the linear transport through the system: the curve linear conductance vs temperature is non-monotonic, with a maximum at a temperature $T^*$ characterizing quantum coherence between both Kondo states.Comment: 20 pages, 17 figure

Exploration for Two-Dimensional Electrides via Database Screening and Ab Initio Calculation

Inspired by the recent demonstration that Ca_{2}N is a two-dimensional electride in which electrons near the Fermi level float between ionic layers, we have conducted a systematic search for 2D electrides by an approach combining crystal structure databases and ab initio electronic structure calculations. Starting from a set of working hypotheses, we have identified six 2D metallic electrides, of which one is nonmagnetic and five are nearly ferromagnetic ferrimagnets with a distinct spin texture. The latter five materials are the first magnetic electrides reported at ambient pressure