Telecom-wavelength conversion in a high optical depth cold atomic system.

We experimentally investigate the frequency down-conversion through the four-wave mixing (FWM) process in a cold 85Rb atomic ensemble, with a diamond-level configuration. An atomic cloud with a high optical depth (OD) of 190 is prepared to achieve a high efficiency frequency conversion. Here, we convert a signal pulse field (795 nm) attenuated to a single-photon level, into a telecom light at 1529.3 nm within near C-band range and the frequency-conversion efficiency can reach up to 32%. We find that the OD is an essential factor affecting conversion efficiency and the efficiency may exceed 32% with an improvement in the OD. Moreover, we note the signal-to-noise ratio of the detected telecom field is higher than 10 while the mean signal count is larger than 0.2. Our work may be combined with quantum memories based on cold 85Rb ensemble at 795 nm and serve for long-distance quantum networks.

3D reconstruction of a gallbladder duplication to guide LC: A case report and literature review.

RATIONALE: Gallbladder duplication is a congenital aberration of the biliary tree, which is rarely encountered in the abdomen. It is a challenge that can be encountered by surgeons and is associated with an increased risk of complications after cholecystectomy. More than 50% of gallbladder duplication cases were undetected on preoperative traditional imaging. In this study, a case of gallbladder duplication in a patient with mild abdominal pain detected using preoperative 3-dimensional (3D) reconstruction of the gallbladder was described for the first time. PATIENT CONCERNS AND DIAGNOSIS: We present a case of gallbladder duplication in a 32-year-old man who was referred to our hospital for recurrent right upper quadrant abdominal pain without any other significant history. INTERVENTIONS AND OUTCOMES: He underwent a 3D reconstruction technique as a supplement for gallbladder duplication that could not be diagnosed using magnetic resonance cholangiopancreatography or other traditional tools. Compared with other diagnostic tools, 3D reconstruction is more visual and accurate for diagnosing gallbladder duplication and guiding laparoscopic cholecystectomy without ductal injuries or other complications. CONCLUSION: Gallbladder duplication is an extremely rare biliary anatomical anomaly; failure to recognize it perioperatively exposes the patient to an increased risk of bile duct injuries. We review 28 cases of missed gallbladder duplication and conclude that less 50% of gallbladder duplication cases were detected via preoperative traditional imaging. We present a case and find that the 3D reconstruction technique can be used as a supplement for gallbladder duplication that could not be diagnosed by using magnetic resonance cholangiopancreatography or other tools. The value of using 3D reconstruction of gallbladder duplication is feasible and innovative, and facilitates guiding to laparoscopic cholecystectomy.

Optical memory for arbitrary perfect Poincaré states in an atomic ensemble.

Inherent spin angular momentum (SAM) and orbital angular momentum (OAM), which manifest as polarization and spatial degrees of freedom (DOFs) of photons, hold a promise of large capability for applications in classical and quantum information processing. To enable these photonic spin and orbital dynamic properties strongly coupled with each other, Poincaré states have been proposed and offer advantages in data multiplexing, information encryption, precision metrology, and quantum memory. However, since the transverse size of Laguerre-Gaussian beams strongly depends on their topological charge numbers | l |, it is difficult to store asymmetric Poincaré states due to the significantly different light-matter interaction for distinct spatial modes. Here, we experimentally realize the storage of perfect Poincaré states with arbitrary OAM quanta using the perfect optical vortex, in which 121 arbitrarily selected perfect Poincaré states have been stored with high fidelity. The reported work has great prospects in optical communication and quantum networks for dramatically increased encoding flexibility of information.

Long-Lived Memory for Orbital Angular Momentum Quantum States.

Quantum memories that are capable of storing multiple spatial modes offer advantages in speed and robustness when incorporated into quantum networks. When it comes to spatial degrees of freedom, orbital angular momentum (OAM) modes have received widespread attention since they enable encoding with inherent infinite number of dimensions. Although the faithful storage of OAM qubits or qutrits has been realized in previous works, the achieved lifetimes are still on the order of a few microseconds as limited by the spatially dependent decoherence. We here demonstrate a long-lived quantum memory for OAM qutrits by suppressing the decoherence in the transverse and longitude direction simultaneously; the achieved fidelity beats the quantum-classical criteria after a storage time of 400 µs, which is 2 orders of magnitude longer than earlier works. The present work is promising for establishing high-dimensional quantum networks.

All-optical reversible single-photon isolation at room temperature.

Nonreciprocal devices operating at the single-photon level are fundamental elements for quantum technologies. Because magneto-optical nonreciprocal devices are incompatible for magnetic-sensitive or on-chip quantum information processing, all-optical nonreciprocal isolation is highly desired, but its realization at the quantum level is yet to be accomplished at room temperature. Here, we propose and experimentally demonstrate two regimes, using electromagnetically induced transparency (EIT) or a Raman transition, for all-optical isolation with warm atoms. We achieve an isolation of 22.52 ± 0.10 dB and an insertion loss of about 1.95 dB for a genuine single photon, with bandwidth up to hundreds of megahertz. The Raman regime realized in the same experimental setup enables us to achieve high isolation and low insertion loss for coherent optical fields with reversed isolation direction. These realizations of single-photon isolation and coherent light isolation at room temperature are promising for simpler reconfiguration of high-speed classical and quantum information processing.

Protective Effects of Allicin on ISO-Induced Rat Model of Myocardial Infarction via JNK Signaling Pathway.

OBJECTIVE: This research was aimed to explore protective effects of allicin on rat model of myocardial infarction via JNK signaling pathway. METHODS: Rat myocardial ischemia model was established with subcutaneous injection of isoproterenol (ISO). Seventy-five rats were randomly divided into 5 groups (n = 15): sham group, ISO group, low-dose group (1.2 mg/kg/days for 7 days), medium-dose group (1.8 mg/kg/days for 7 days), and high-dose group (3.6 mg/kg/days for 7 days). Routine HE staining and Masson staining were performed to observe myocardial histopathology. The expression of oxidative stress-related indicators, heart tissue apoptosis-related proteins, and JNK and p-JNK proteins were measured for different groups. RESULTS: Compared with the sham group, the T wave value of the ISO group was significantly increased (p < 0.01). When allicin was administered, the T wave values at different time points in all groups were all decreased. Compared with the sham group, the ratio of eNOS, Bcl-2/Bax was significantly decreased, and p-eNOS, iNOS, caspase-3, caspase-9, and Cyt-c were significantly elevated in the ISO group (p < 0.05). After allicin was administered, significant changes in these proteins were observed in the medium- and high-dose groups. There was no significant change in the expression of JNK protein in the ISO group compared with the sham group; however, the expression of eNOS and p-JNK protein were significantly upregulated (p < 0.01) and the expression of p-eNOS and iNOS were significantly downregulated (p < 0.01). When allicin was administered, expression of p-JNK protein was significantly downregulated. CONCLUSION: Allicin can reduce oxidative stress damage and cardiomyocyte apoptosis in rat model of myocardial infarction and can significantly regulate JNK signaling pathway.

Baicalein Protects Rats with Diabetic Cardiomyopathy Against Oxidative Stress and Inflammation Injury via Phosphatidylinositol 3-Kinase (PI3K)/AKT Pathway.

BACKGROUND The aim of this study was to explore the effect of baicalein on diabetic cardiomyopathy (DCM) rats and the mechanisms involved, and to determine the theoretical basis for clinical anti-tumor therapy. MATERIAL AND METHODS DCM rat model was induced with a single injection of streptozotocin. Then, DCM rats were treated with baicalein alone or co-treated with baicalein and PI3K/Akt inhibitor. Myocardial pathological changes were detected by HE and Masson staining. The activities of SOD, GSH-Px, and MDA in myocardial tissue were measured by biochemical tests. The levels of TNF-α, IL-1ß, and cTn-I were examined by ELISA. NADP+/NADPH ratio was measured with the NADP+/NADPH assay kit. RT-PCR was used to detect the levels of PI3K and Akt. The levels of Bax, Bcl-2, Caspase-3, GSK-3ß, PI3K, and Akt were detected by Western blot. RESULTS Baicalein could improve pathological injury. SOD and GSH-Px activity decreased while the level of MDA increased in myocardial tissue. Baicalein treatment enhanced SOD activity in a dose-dependent manner but markedly reduced MDA. Similar changes were observed in both serum inflammatory factors and the NADP+/NADPH ratio. After adding PI3K-Akt inhibitor, the levels of PI3K and Akt mRNA expression were significantly decreased, but were not significantly different from the DCM group. Levels of Bcl-2, PI3K, p-GSK-3ß/GSK-3ß, and p-Akt were decreased in the DCM group, while the levels of Bax and Caspase-3 were obviously increased. CONCLUSIONS Baicalein can protect DCM rats against damage from oxidative stress and inflammation in myocardial tissue, and PI3K/Akt signaling pathway may be involved to mediating these effects.