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1.
Phys Rev Lett ; 123(23): 233603, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31868469

RESUMO

Quantum simulations of Fermi-Hubbard models have been attracting considerable effort in the optical lattice research, with the ultracold antiferromagnetic atomic phase reached at half filling in recent years. An unresolved issue is to dope the system while maintaining the low thermal entropy. Here we propose to achieve the low temperature phase of the doped Fermi-Hubbard model using incommensurate optical lattices through adiabatic quantum evolution. In this theoretical proposal, we find that one major problem about the adiabatic doping is atomic localization in the incommensurate lattice, potentially causing an exponential slowing down of the adiabatic procedure. We study both one- and two-dimensional incommensurate optical lattices, and find that the localization prevents efficient adiabatic doping in the strong lattice regime for both cases. With density matrix renormalization group calculation, we further show that the slowing down problem in one dimension can be circumvented by considering interaction induced many-body delocalization, which is experimentally feasible using Feshbach resonance techniques. This protocol is expected to be efficient as well in two dimensions where the localization phenomenon is less stable.

2.
Phys Rev Lett ; 122(25): 253201, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31347860

RESUMO

Stimulated Raman adiabatic passage (stirap) allows efficiently transferring the populations between two discrete quantum states and has been used to prepare molecules in their rovibrational ground state. In realistic molecules, a well-resolved intermediate state is usually selected to implement the resonant stirap. Because of the complex molecular level structures, the detuned stirap always coexists with the resonant stirap and may cause unexpected interference phenomenon. However, it is generally accepted that the detuned stirap can be neglected if compared with the resonant stirap. Here we report on the first observation of interference between the resonant and detuned stirap in the adiabatic creation of ^{23}Na^{40}K ground-state molecules. The interference is identified by observing that the number of Feshbach molecules after a round-trip stirap oscillates as a function of the hold time, with a visibility of about 90%. This occurs even if the intermediate excited states are well resolved, and the single-photon detuning of the detuned stirap is about 1 order of magnitude larger than the linewidth of the excited state and the Rabi frequencies of the stirap lasers. Moreover, the observed interference indicates that if more than one hyperfine level of the ground state is populated, the stirap prepares a coherent superposition state among them, but not an incoherent mixed state. Further, the purity of the hyperfine levels of the created ground state can be quantitatively determined by the visibility of the oscillation.

3.
Science ; 363(6424): 261-264, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30655438

RESUMO

Resonances in ultracold collisions involving heavy molecules are difficult to simulate theoretically and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between potassium-40 (40K) atoms and sodium-23-potassium-40 (23Na40K) molecules in the rovibrational ground state. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atom-molecule Feshbach resonances are identified by observing an enhancement of the loss. We have observed 11 resonances in the magnetic field range of 43 to 120 gauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with exceptional resolution and will help to improve understanding of ultracold collisions.

4.
Biochem Biophys Res Commun ; 505(4): 1236-1243, 2018 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-30333091

RESUMO

Diabetic retinopathy (DR) is a progressive microvascular complication associated with diabetes, and remains the leading cause of preventable blindness worldwide. Recent studies have revealed that microRNAs (miRNAs) were involving in the physiological and pathophysiological processes of diabetes and its microvascular and macrovascular complications. The purpose of the current investigation is to identify the candidate miR-211 as a novel biomarker for occurrence and progression of DR in clinical study and experimental research. Firstly, miR-211 was considered as a candidate miRNA identifying by miRNA microarray analysis, Venn diagram analysis, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and receiver operating characteristic curve in clinical study. Then, the predicted Sirtuin 1 (SIRT1) may be the target gene of miR-211 searching by TargetScan 7.2. Moreover, miR-211 was significantly up-regulated, while SIRT1 mRNA significantly down-regulated measuring by qRT-PCR, meanwhile, SIRT1 protein was significantly down-regulated in coincidence with SIRT1 mRNA detecting by western blot, and even aggravated associated with diabetes duration in diabetic retinal tissues of vivo experiment. Additionally, miR-211 was directly targeted SIRT1 confirming by dual-luciferase reporter assay. Furthermore, with transfection of antagomiR-211, the apoptosis of HUVECs was significantly suppressed employing by flow cytometry analysis, nevertheless the viability of HUVECs was significantly promoted exploiting by Cell Counting Kit-8 assay. Finally, SIRT1 mRNA and SIRT1 protein were significantly up-regulated testing by qRT-PCR and western blot respectively in hyperglycemic HUVECs transfected with antagomiR-211 of vitro experiment. Consequently, the current clinical study and experimental research imply that serum miR-211 as a novel biomarker with high sensitivity and specificity could be associated with occurrence and progression of DR via targeting SIRT1.


Assuntos
Retinopatia Diabética/diagnóstico , MicroRNAs/sangue , Sirtuína 1/genética , Adulto , Animais , Biomarcadores/sangue , Células Cultivadas , Retinopatia Diabética/sangue , Retinopatia Diabética/genética , Retinopatia Diabética/patologia , Feminino , Regulação da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Masculino , MicroRNAs/metabolismo , Ratos Wistar , Retina/metabolismo , Retina/patologia , Sirtuína 1/metabolismo
5.
Int J Ophthalmol ; 9(5): 757-62, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27275436

RESUMO

AIM: To identify possible differences of efficacy, safety, predictability, higher-order aberrations and corneal biomechnical parameters after small-incision lenticule extraction (SMILE) and femtosecond lenticule extraction (FLEx). METHODS: A systematic literature retrieval was conducted in Medline, Embase and the Cochrane Library, up to October, 2015. The included studies were subject to a Meta-analysis. Comparison between SMILE and FLEx was measured as pooled odds ratio (OR) or weighted mean differences (WMD). Of 95% confidence intervals (CI) were used to analyze data. RESULTS: A total of seven studies were included. Firstly, there were no differences in uncorrected distance visual acuity (UDVA) 20/20 or better (OR, 1.37; 95% CI, 0.69 to 2.69; P=0.37) and logMAR UDVA (WMD, -0.02; 95% CI, -0.05 to 0.01; P=0.17) after SMILE versus FLEx. We found no differences in corrected distance visual acuity (CDVA) unchanged (OR, 0.98; 95% CI, 0.46 to 2.11; P=0.97) and logMAR CDVA (WMD, -0.00; 95% CI, -0.01 to 0.01; P=0.90) either. Secondly, we found no differences in refraction within ±1.00 D (OR, 0.98; 95% CI, 0.13 to 7.28; P=0.99) and ±0.50 D (OR, 1.62; 95% CI, 0.62 to 4.28; P=0.33) of target postoperatively. Thirdly, for higher-order aberrations, we found no differences in the total higher-order aberrations (WMD, -0.04; 95% CI, -0.09 to 0.01; P=0.14), coma (WMD, -0.04; 95% CI, -0.09 to 0.01; P=0.11), spherical (WMD, 0.01; 95% CI, -0.02 to 0.03; P=0.60) and trefoil (WMD, -0.00; 95% CI, -0.04 to 0.03; P=0.76). Furthermore, for corneal biomechanical parameters, we also found no differences (WMD, 0.08; 95% CI, -0.17 to 0.33; P=0.54) after SMILE versus FLEx. CONCLUSION: There are no statistically differences in efficacy, safety, predictability, higher-order aberrations and corneal biomechnical parameters postoperative between SMILE and FLEx.

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