RESUMO
EuCd_{2}As_{2} is now widely accepted as a topological semimetal in which a Weyl phase is induced by an external magnetic field. We challenge this view through firm experimental evidence using a combination of electronic transport, optical spectroscopy, and excited-state photoemission spectroscopy. We show that the EuCd_{2}As_{2} is in fact a semiconductor with a gap of 0.77 eV. We show that the externally applied magnetic field has a profound impact on the electronic band structure of this system. This is manifested by a huge decrease of the observed band gap, as large as 125 meV at 2 T, and, consequently, by a giant redshift of the interband absorption edge. However, the semiconductor nature of the material remains preserved. EuCd_{2}As_{2} is therefore a magnetic semiconductor rather than a Dirac or Weyl semimetal, as suggested by ab initio computations carried out within the local spin-density approximation.
RESUMO
AIMS: To investigate the intracellular lipid accumulation inhibitory effect of spent culture medium extract and the cytoplasmic fraction of Weissella koreensis OK1-6 cells isolated from kimchi in differentiating 3T3-L1 cells. METHODS AND RESULTS: Differentiating 3T3-L1 cells were treated with either cytoplasmic fraction of W. koreensis OK1-6 cells or its spent media for 4 days. Both the spent culture medium extract and cytoplasmic fraction of W. koreensis OK1-6 cells significantly decreased the triglyceride concentration and intracellular lipid accumulation in the treated groups compared with the control group. The mRNA expression levels of C/EBP-α, one of the major transcriptional factors involved in adipocyte differentiation, were significantly less expressed in 3T3-L1 cells treated with the spent medium and cytoplasmic fraction. The expressions of aP2, fatty acid synthase (FAS) and SREBP1 genes were also decreased significantly. CONCLUSIONS: These results suggested that W. koreensis OK1-6 could play a crucial role in preventing intracellular lipid accumulation by down-regulating the expression of adipocyte-specific genes C/EBPα, aP2, SREBP1 and FAS. SIGNIFICANCE AND IMPACT OF THE STUDY: These results may contribute to nutraceutical and food industries in developing probiotic-based therapies for the treatment and prevention of obesity.