Quantum-Memory-Enhanced Preparation of Nonlocal Graph States.

Graph states are an important class of multipartite entangled states. Previous experimental generation of graph states and in particular the Greenberger-Horne-Zeilinger (GHZ) states in linear optics quantum information schemes is subjected to an exponential decay in efficiency versus the system size, which limits its large-scale applications in quantum networks. Here, we demonstrate an efficient scheme to prepare graph states with only a polynomial overhead using long-lived atomic quantum memories. We generate atom-photon entangled states in two atomic ensembles asynchronously, retrieve the stored atomic excitations only when both sides succeed, and further project them into a four-photon GHZ state. We measure the fidelity of this GHZ state and further demonstrate its applications in the violation of Bell-type inequalities and in quantum cryptography. Our work demonstrates the prospect of efficient generation of multipartite entangled states in large-scale distributed systems with applications in quantum information processing and metrology.

[Evaluation of visceral adipose in abdominal obesity and its clinical application].

OBJECTIVE: To compare the values of measurements of obesity, including body mass index(BMI), waist circumference (WC), waist-to-hip ratio (WHR), bioelectrical impedance analyzer(BIA) (fat mass and FAT%), ultrasonography (US) (subcutaneous fat distance and intraabdominal fat distance), and computed tomography (CT) in predicting the quantification of visceral adipose in abdominal obesity, and to evaluate the best cut-off point, sensitivity and specificity of these methods. METHODS: 4,301 inpatients with hypertension, 2,155 males and 2,146 females, aged (56.4 +/- 13.8) (11 - 89), all with at least 1 risk factor of cardiovascular diseases, underwent simple body fat measurement. 3458 received BIA, 2,553 received B mode ultrasonography, 1039 underwent CT examination, and 659 received all kinds of examination. Abdominal visceral adipose area (VA) measured with CT >or= 100 cm(2) was the diagnostic criteria of visceral fat obesity (VFO). Receiver operating characteristic (ROC) curve was used to analyze the body fat indexes to determine the best cut-off point. RESULTS: (1) It was accurate for WC, fat mass, BMI, intraabdominal fat distance, FAT%, and WHR were all accurate in diagnosis of VFO with the values of area under ROC of 0.730 - 0.867. WC was the most effective measurement. (2) The best cut-off points of these methods in predicting abdominal visceral obesity in males and females were as follows: WC: 89.5 cm and 85.5 cm for WC. 25 kg/m(2) and 26 kg/m(2) for BMI, 0.97 and 0.95 for WHR, 29% and 38% for fat composition, 18.6 kg, and 20.4 kg for fat mass, and 38.5 mm and 34.7 mm for intraabdominal fat distance. CONCLUSIONS: WC, fat mass, BMI, intraabdominal fat distance, simple fat parameters, and WHR all can predict visceral adipose in abdominal obesity, in which WC is the best. For a given WC, the type of obesity can be determined by BIA and US.

[Relationship of different types of abdominal obesity to risk of metabolic syndrome].

OBJECTIVE: To explore the relationship of different types of abdominal obesity to risk of metabolic syndrome (MS). METHODS: Visceral fat area (VA) and substantial fat area (SA) were assessed by CT in 846 patients, 470 males and 376 females, aged 55 +/- 12, who suffered from at least one cardiometabolic risk factor and divided into 4 groups according to their VA and waist circumference (WC): non-obesity, masked visceral fat obesity (VFO), pseudo-VFO, and VFO groups. Blood pressure, fasting blood glucose, fasting serum insulin, and lipid profile were also measured. The MS risks of different types of abdominal obesity were compared. RESULTS: The prevalence rate of masked VFO of males was 10.9% (51/470), significantly higher than that of female (4.8%, 18/376). The prevalence rate of MS of the male patients with masked VFO was 43.1%, significantly higher than that of those in non-obesity group (25.0%), and lower than those of the males in the pseudo-VFO group (78.7%) and in the VFO group (88.6%), whereas the MS prevalence rate of the males in the pseudo-VFO group was significantly higher than those in the non-obesity and masked VFO groups. On the other hand, the MS prevalence rate of the female patients with masked VFO was 33.3%, not significantly different from that of the female patients in the non-obesity group (31.2%), but significantly lower than those of the pseudo-VFO and VFO groups (78.7% and 90.9% respectively). The MS prevalence rate of the female pseudo-VFO patients was also significantly higher than those in the non-obesity and masked VFO groups. Logistic regression analysis showed that WC and VA were independent risk factors for MS [OR (95% CI) = 1.13 (1.10-1.17), 1.01 (1.01-1.02), respectively, P < 0.01). CONCLUSION: Different types of abdominal obesity have important impacts on the risk of metabolic syndrome. Masked VFO, even though with normal WC, and pseudo-VFO have considerably higher cardiometabolic risks.