Spin-orbit coupling (SOC) is central to many physical phenomena, including fine structures of atomic spectra and topological phases in ultracold atoms. Whereas, in general, SOC is fixed in a system, laser-atom interaction provides a means to create and control synthetic SOC in ultracold atoms 1 . Despite significant experimental progress in this area 2-8 , two-dimensional (2D) synthetic SOC, which is crucial for exploring two-and threedimensional topological phases, is lacking. Here, we report the experimental realization of 2D SOC in ultracold 40 K Fermi gases using three lasers, each of which dresses one atomic hyperfine spin state. Through spin-injection radiofrequency (rf) spectroscopy 4 , we probe the spin-resolved energy dispersions of the dressed atoms, and observe a highly controllable Dirac point created by the 2D SOC. These results constitute a step towards the realization of new topological states of matter.There have been many theoretical proposals for creating multi-dimensional SOC in ultracold atoms 9-14 , so as to access novel macroscopic quantum phenomena and quantum topological states [15][16][17][18][19][20][21][22][23][24] . Whereas these proposals have not been realized in laboratories, physicists have also just begun to explore topological phenomena in optical lattices [25][26][27][28] . Here, we use the Raman scheme to produce a highly controllable 2D synthetic SOC for an ultracold Fermi gas of 40 K. Such SOC allows us to create and manipulate a single stable Dirac point on a 2D plane, which is detected by spin-injection rf spectroscopy 4 .We apply three far-detuned lasers propagating on the x-y plane to couple three ground hyperfine spin states, within the 4 2 S 1/2 ground electronic manifold, |1 = |F = 9/2, m F = 3/2 , |2 = |F = 9/2, m F = 1/2 and |3 = |F = 7/2, m F = 1/2 , where (F, m F ) are the quantum numbers for hyperfine spin states as shown in Fig. 1a, to the electronically excited states. Unlike the tripod scheme, where a single excited state is considered [9][10][11][15][16][17][18] , in the 40 K used here the excited states include a fine-structure doublet 4 2 P 1/2 (D 1 line) and 4 2 P 3/2 (D 2 line) with a finestructure splitting of ∼3.4 nm. Each of two D-line components also has hyperfine structures. After adiabatically eliminating excited states, the ring scheme proposed in ref. 12 is realized for three cyclically coupled states, with a generalization to arbitrary laser configurations. The Hamiltonian is written as( 1) where p denotes the momentum of atoms, k i (|k i | = 2π/λ i ) and ω i are the wavevectors and frequencies of the three lasers, Ω i are the Rabi frequencies, i, j are the indices for the three ground hyperfine spin and the excited states respectively, ε i and E j are the ground and excited state energies, n is the total number of the excited states and M ij is the matrix element of the dipole transition. Different from refs 9,10,15, each hyperfine ground spin state here is dressed by only one laser field, regardless of the excited states it is coupled to. A gau...

The recent experimental realization of synthetic spin-orbit coupling (SOC) opens a new avenue for exploring novel quantum states with ultracold atoms. However, in experiments for generating twodimensional SOC (e.g., Rashba type), a perpendicular Zeeman field, which opens a band gap at the Dirac point and induces many topological phenomena, is still lacking. Here we theoretically propose and experimentally realize a simple scheme for generating two-dimension SOC and a perpendicular Zeeman field simultaneously in ultracold Fermi gases by tuning the polarization of three Raman lasers that couple three hyperfine ground states of atoms. The resulting band gap opening at the Dirac point is probed using spin injection radio-frequency spectroscopy. Our observation may pave the way for exploring topological transport and topological superfluids with exotic Majorana and Weyl fermion excitations in ultracold atoms. Spin-orbit coupling (SOC), the intrinsic interaction between a particle spin and its motion, plays a key role in many important phenomena, ranging from anomalous Hall effects [1] to topological insulators and superconductors [2][3][4]. Although SOC is ubiquitous in nature, the experimental control and observation of SOC induced effects are quite difficult. In this context, the recent experimental realization of synthetic SOC for cold atoms [5][6][7][8][9][10][11][12] provides a completely new and tunable platform for exploring SOC related physics. Early experiments only realized the 1D SOC (i.e., an equal sum of Rashba and Dresselhaus coupling, ∝ k x σ y ) using two counterpropagating Raman lasers [5][6][7][8][9][10][11][12]. Many theoretical proposals have explored the generation of 2D SOC (i.e., ∝ αk x σ y + βk y σ x ) [13][14][15][16][17][18][19][20] as well as their interesting physical properties in Bose and Fermi gases [21][22][23][24][25][26]. Recently, 2D SOC was also experimentally realized in ultracold 40 K Fermi gases [27] using three Raman lasers and the associated stable Dirac point on a 2D momentum plane was observed [27].The experimental generation of SOC is usually accompanied with a Zeeman field, which breaks various symmetries of the underlying system and induces interesting quantum phenomena. The accompanied Zeeman field can be in-plane (e.g., V σ y for SOC ∝ k x σ y ) or perpendicular (e.g., V σ z for SOC ∝ αk x σ y + βk y σ x ). The in-plane Zeeman field, while preserves the Dirac point, makes the band dispersion asymmetric, leading to new quantum states such as Fulde-Ferrell superfluids [28][29][30][31]. In contrast, the perpendicular Zeeman field can open a topological band gap at the Dirac point of the SOC, leading to many interesting topological transport [1] and superfluid phenomena, such as the long-sought Majorana [32,33] and Weyl [24,34,35] fermions. In cold atom experiments, although both in-plane and perpendicular Zeeman fields have been realized with 1D SOC, only inplane Zeeman field was realized with 2D SOC [27]. A perpendicular Zeeman field with 2D SOC is still lacked but highly...

Increasing energy expenditure through activation of brown adipose tissue (BAT) is a critical approach to treating obesity and diabetes. In this study, rutin, a natural compound extracted from mulberry and a drug used as a capillary stabilizer clinically for many years without any side effects, regulated whole-body energy metabolism by enhancing BAT activity. Rutin treatment significantly reduced adiposity, increased energy expenditure, and improved glucose homeostasis in both genetically obese (Db/Db) and diet-induced obesity (DIO) mice. Rutin also induced brown-like adipocyte (beige) formation in subcutaneous adipose tissue in both obesity mouse models. Mechanistically, we found that rutin directly bound to and stabilized SIRT1, leading to hypoacetylation of peroxisome proliferator-activated receptor γ coactivator-1α protein, which stimulated Tfam transactivation and eventually augmented the number of mitochondria and UCP1 activity in BAT. These findings reveal that rutin is a novel small molecule that activates BAT and may provide a novel therapeutic approach to the treatment of metabolic disorders.-Yuan, X., Wei, G., You, Y., Huang, Y., Lee, H. J., Dong, M., Lin, J., Hu, T., Zhang, H., Zhang, C., Zhou, H., Ye, R., Qi, X., Zhai, B., Huang, W., Liu, S., Xie, W., Liu, Q., Liu, X., Cui, C., Li, D., Zhan, J., Cheng, J., Yuan, Z., Jin, W. Rutin ameliorates obesity through brown fat activation.

ObjectiveDietary fibre has beneficial effects on energy metabolism, and the majority of studies have focused on short-chain fatty acids produced by gut microbiota. Ginseng has been reported to aid in body weight management, however, its mechanism of action is not yet clear. In this study, we focused on the potential modulating effect of ginseng on gut microbiota, aiming to identify specific strains and their metabolites, especially long-chain fatty acids (LCFA), which mediate the anti-obesity effects of ginseng.DesignDb/db mice were gavaged with ginseng extract (GE) and the effects of GE on gut microbiota were evaluated using 16S rDNA-based high throughput sequencing. To confirm the candidate fatty acids, untargeted metabolomics analyses of the serum and medium samples were performed.ResultsWe demonstrated that GE can induce Enterococcus faecalis, which can produce an unsaturated LCFA, myristoleic acid (MA). Our results indicate that E. faecalis and its metabolite MA can reduce adiposity by brown adipose tissue (BAT) activation and beige fat formation. In addition, the gene of E. faecalis encoding Acyl-CoA thioesterases (ACOTs) exhibited the biosynthetic potential to synthesise MA, as knockdown (KD) of the ACOT gene by CRISPR-dCas9 significantly reduced MA production. Furthermore, exogenous treatment with KD E. faecalis could not reproduce the beneficial effects of wild type E. faecalis, which work by augmenting the circulating MA levels.ConclusionsOur results demonstrated that the gut microbiota-LCFA-BAT axis plays an important role in host metabolism, which may provide a strategic advantage for the next generation of anti-obesity drug development.

A fast silyl derivatization technique for simultaneous GC/ MS analysis of alkylphenols, chlorophenols, and bisphenol A was developed. The analytes were silylized with an excess amount of bis(trimethylsilyl)trifluoroacetamide (BSTFA) followed by hydrolysis of excess silyl reagent with water. Reaction rates of derivatization were studied in various solvents and found to be fastest in acetone. Derivatization reaction in acetone was completed quantitatively within 15 s at room temperature while it took more than 1 h in other solvents studied. Similar results were obtained in mixed solvents with acetone if the content of acetone was higher than 60% (v/v). Since water-immiscible solvents such as dichloromethane or hexane are frequently used in the extraction of phenolic analytes in various sample matrixes, acetone can be added to the extracts in order to accelerate the reaction rate of derivatization. Stability of the derivatives in sample for long-term storage was ensured by hydrolyzing excess derivatizing reagent, BSTFA, with a spike of water followed by dehydration using anhydrous sodium sulfate. On the basis of the above results, a derivatizing treatment kit was designed to improve the convenience of analysis. It was possible to treat sample within several minutes successfully by using the kit. So fast simultaneous determination of those anlaytes by GC/MS was possible with improved convenience as well as sensitivity and reproducibility.