Creation of memory-memory entanglement in a metropolitan quantum network.

Towards realizing the future quantum internet1,2, a pivotal milestone entails the transition from two-node proof-of-principle experiments conducted in laboratories to comprehensive multi-node set-ups on large scales. Here we report the creation of memory-memory entanglement in a multi-node quantum network over a metropolitan area. We use three independent memory nodes, each of which is equipped with an atomic ensemble quantum memory3 that has telecom conversion, together with a photonic server where detection of a single photon heralds the success of entanglement generation. The memory nodes are maximally separated apart for 12.5 kilometres. We actively stabilize the phase variance owing to fibre links and control lasers. We demonstrate concurrent entanglement generation between any two memory nodes. The memory lifetime is longer than the round-trip communication time. Our work provides a metropolitan-scale testbed for the evaluation and exploration of multi-node quantum network protocols and starts a stage of quantum internet research.

Main components from cultivated and wild Nardostachyos Radix et Rhizoma by LC-MS and GC-MS / 中国中药杂志

In this study, ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and gas chromatography-mass spectrometry(GC-MS) were combined with non-targeted metabonomic analysis based on multivariate statistics analysis, and the content of five indicative components in nardosinone was determined and compared by UPLC. The main chemical components of Nardostachyos Radix et Rhizoma with imitative wild cultivation and wild Nardostachyos Radix et Rhizoma were comprehensively analyzed. The results of multivariate statistical analysis based on liquid chromatography-mass spectrometry(LC-MS) and GC-MS were consistent. G1 and G2 of the imitative wild cultivation group and G8-G19 of the wild group were clustered into category 1, while G7 of the wild group and G3-G6 of the imitative wild cultivation group were clustered into category 2. After removing the outlier data of G1, G2, and G7, G3-G6 of the imitative wild cultivation group were clustered into one category, and G8-G19 of the wild group were clustered into the other category. Twenty-six chemical components were identified according to the positive and negative ion modes detected by LC-MS. The content of five indicative components(VIP>1.5) was determined using UPLC, revealing that chlorogenic acid, isochlorogenic acid A, isochlorogenic acid C, linarin, nardosinone, and total content in the imitative wild cultivation group were 1.85, 1.52, 1.26, 0.90, 2.93, and 2.56 times those in the wild group, respectively. OPLS-DA based on GC-MS obtained 10 diffe-rential peaks. Among them, the relative content of α-humulene and aristolene in the imitative wild cultivation group were extremely significantly(P<0.01) and significantly(P<0.05) higher than that in the wild group, while the relative content of 7 components such as 5,6-epoxy-3-hydroxy-7-megastigmen-9-one, γ-eudesmol, and juniper camphor and 12-isopropyl-1,5,9-trimethyl-4,8,13-cyclotetrade-catriene-1,3-diol was extremely significantly(P<0.01) and significantly(P<0.05) lower than that in the wild group, respectively. Therefore, the main chemical components of the imitative wild cultivation group and wild group were basically the same. However, the content of non-volatile components in the imitative wild cultivation group was higher than that in the wild group, and the content of some volatile components was opposite. This study provides scientific data for the comprehensive evaluation of the quality of Nardostachyos Radix et Rhizoma with imitative wild cultivation and wild Nardostachyos Radix et Rhizoma.

Quality evaluation of Huocao based on UPLC fingerprint and multi-component content determination / 中国中药杂志

Huocao(a traditional Chinese herbal medicine) moxibustion is a characteristic technology in Yi medicine suitable for cold-dampness diseases. Huocao, as the moxibustion material, is confusedly used in clinical practice and little is known about its quality control. In this study, UPLC method was used to establish the chemical fingerprint of non-volatile components in Huocao, and the contents of eight phenolic acids such as chlorogenic acid were determined. Multivariate statistical analysis was performed to obtain the indicator components of Huocao for quality evaluation, and thus a comprehensive evaluation system for the quality of Huocao was built. The UPLC fingerprints of 49 batches of Huocao were established, and there were 20 common peaks, of which eight phenolic acids including neochlorogenic acid and chlorogenic acid were identified. Except for three batches of Huocao, the similarity of the other 46 batches was higher than 0.89, suggesting that the established fingerprint method could be used for quality control of the medicinal herb. The correlation coefficient between entropy weight score of the eight phenolic acids and comprehensive fingerprint score in Huocao was 0.875(P<0.01), which indicated that the eight phenolic acids could be used as indicator components for the quality evaluation of Huocao. Furthermore, in multivariate statistical analysis on the common peaks of fingerprint and the contents of the eight phenolic acids, chlorogenic acid, isochlorogenic acid A and isochlorogenic acid C were screened to be the indicator components. The results revealed that the proposed method achieved a simple and accurate quality control of Huocao based on UPLC fingerprint and multi-component content determination, which provided useful data for establishing the quality standard of Huocao.

Selection and validation of reference genes for quantitative real-time PCR analysis in Paeonia veitchii / 中国中药杂志

Paeonia veitchii and P. lactiflora are both original plants of the famous Chinese medicinal drug Paeoniae Radix Rubra in the Chinese Pharmacopoeia. They have important medicinal value and great potential in the flower market. The selection of stable and reliable reference genes is a necessary prerequisite for molecular research on P. veitchii. In this study, two reference genes, Actin and GAPDH, were selected as candidate genes from the transcriptome data of P. veitchii. The expression levels of the two candidate genes in different tissues(phloem, xylem, stem, leaf, petiole, and ovary) and different growth stages(bud stage, flowering stage, and dormant stage) of P. veitchii were detected using real-time fluorescence quantitative technology(qRT-PCR). Then, the stability of the expression of the two reference genes was comprehensively analyzed using geNorm, NormFinder, BestKeeper, ΔCT, and RefFinder. The results showed that the expression patterns of Actin and GAPDH were stable in different tissues and growth stages of P. veitchii. Furthermore, the expression levels of eight genes(Pv-TPS01, Pv-TPS02, Pv-CYP01, Pv-CYP02, Pv-CYP03, Pv-BAHD01, Pv-UGT01, and Pv-UGT02) in different tissues were further detected based on the transcriptome data of P. veitchii. The results showed that when Actin and GAPDH were used as reference genes, the expression trends of the eight genes in different tissues of P. veitchii were consistent, validating the reliability of Actin and GAPDH as reference genes for P. veitchii. In conclusion, this study finds that Actin and GAPDH can be used as reference genes for studying gene expression levels in different tissues and growth stages of P. veitchii.

Postselected Entanglement between Two Atomic Ensembles Separated by 12.5 km.

Quantum internet gives the promise of getting all quantum resources connected, and it will enable applications far beyond a localized scenario. A prototype is a network of quantum memories that are entangled and well separated. In this Letter, we report the establishment of postselected entanglement between two atomic quantum memories physically separated by 12.5 km directly. We create atom-photon entanglement in one node and send the photon to a second node for storage via electromagnetically induced transparency. We harness low-loss transmission through a field-deployed fiber of 20.5 km by making use of frequency down-conversion and up-conversion. The final memory-memory entanglement is verified to have a fidelity of 90% via retrieving to photons. Our experiment makes a significant step forward toward the realization of a practical metropolitan-scale quantum network.

UPLC fingerprint and indicator components of Boenninghausenia albiflora var. albiflora / 中国中药杂志

The fingerprint of Boenninghausenia albiflora var. albiflora was established by ultra performance liquid chromatography(UPLC), and the content of 12 active components including chlorogenic acid was determined. Multivariate statistical analysis was used to explore the indicator components of B. albiflora var. albiflora and a comprehensive evaluation system was created for the quality of B. albiflora var. albiflora. In this study, 33 batches of B. albiflora var. albiflora with different sources were collected and studied, and the UPLC fingerprint of B. albiflora var. albiflora was developed. There were 37 common peaks, of which 12 components were identified, and the content of these 12 components was measured. In combination of the common peaks and the content of chemical components, multivariate statistical analysis was performed, and the results showed that 6 components [daphnoretin, isoimperatorin, astragalin, imperatorin, neochlorogenic acid, and isoquercitrin(weight coefficient>0.1)] were selected as chemical markers for the quality of B. albiflora var. albiflora. Technique for order of preference by similarity to ideal solution(TOPSIS) analysis and chemometrics revealed that the quality of S32, S28 and S29 were superior, while that of S12, S7 and S16 were inferior. The quality evaluation method of B. albiflora var. albiflora constructed in this study was accurate and reliable, with simpleness and easiness to operate. It is suggested that the 6 above-mentioned active components could be used as indicator components for quality control of B. albiflora var. al-biflora. The samples were harvested during the flowering and fruiting period, which is from the beginning of July to the end of August.

Improved Spatial Resolution Achieved by Chromatic Intensity Interferometry.

Interferometers are widely used in imaging technologies to achieve enhanced spatial resolution, but require that the incoming photons be indistinguishable. In previous work, we built and analyzed color erasure detectors, which expand the scope of intensity interferometry to accommodate sources of different colors. Here we demonstrate experimentally how color erasure detectors can achieve improved spatial resolution in an imaging task, well beyond the diffraction limit. Utilizing two 10.9-mm-aperture telescopes and a 0.8 m baseline, we measure the distance between a 1063.6 and a 1064.4 nm source separated by 4.2 mm at a distance of 1.43 km, which surpasses the diffraction limit of a single telescope by about 40 times. Moreover, chromatic intensity interferometry allows us to recover the phase of the Fourier transform of the imaged objects-a quantity that is, in the presence of modest noise, inaccessible to conventional intensity interferometry.

Non-Line-of-Sight Imaging with Picosecond Temporal Resolution.

Non-line-of-sight (NLOS) imaging enables monitoring around corners and is promising for diverse applications. The resolution of transient NLOS imaging is limited to a centimeter scale, mainly by the temporal resolution of the detectors. Here, we construct an up-conversion single-photon detector with a high temporal resolution of ∼1.4 ps and a low noise count rate of 5 counts per second (cps). Notably, the detector operates at room temperature, near-infrared wavelength. Using this detector, we demonstrate high-resolution and low-noise NLOS imaging. Our system can provide a 180 µm axial resolution and a 2 mm lateral resolution, which is more than 1 order of magnitude better than that in previous experiments. These results open avenues for high-resolution NLOS imaging techniques in relevant applications.

Diarrhea-predominant irritable bowel syndrome of spleen deficiency and damp excess treated with fire needling therapy with filiform needle and acupoint application therapy: a randomized controlled trial / 中国针灸

OBJECTIVE@#To compare the clinical therapeutic effect on diarrhea-predominant irritable bowel syndrome (IBS-D) of spleen deficiency and damp excess among fire needling therapy with filiform needle combined with acupoint application therapy, simple acupoint application therapy and pinaverium bromide tablets, and explore the mechanism on the improvements in IBS-D.@*METHODS@#A total of 150 patients with IBS-D of spleen deficiency and damp excess were randomized into a combined treatment group (50 cases, 14 cases dropped off), an acupoint application group (50 cases, 16 cases dropped off ) and a western medication group (50 cases, 13 cases dropped off ). In the western medication group, pinaverium bromide tablets were prescribed for oral administration, 50 mg per time, three times a day. In the acupoint application group, the herbal plaster of @*RESULTS@#Except the score for abdominal pain in the acupoint application group and the scores for abdominal pain and abdominal distention in the western medication group after 7 days of treatment, the scores for abdominal pain, abdominal distention, defecation frequency, stool form and incomplete bowel movement after 7 and 28 days of treatment were all reduced as compared with those before treatment in each group separately (@*CONCLUSION@#The combined treatment with the fire needling therapy with filiform needle and the acupoint application therapy effectively relieves the clinical symptoms, improves the quality of life and strengthens the immunity in the patients with IBS-D. The therapeutic effect of this combined regimen is better than either simple acupoint application therapy or the oral medication of pinaverium bromide. The mechanism may be related to the regulation of the levels of T lymphocyte subsets and the modulation of the expressions of 5-HT3R and 5-HT4R mRNA in colon tissue.

Chromatic interferometry with small frequency differences.

By developing a 'two-crystal' method for color erasure, we can broaden the scope of chromatic interferometry to include optical photons whose frequency difference falls outside of the 400 nm to 4500 nm wavelength range, which is the passband of a PPLN crystal. We demonstrate this possibility experimentally, by observing interference patterns between sources at 1064.4 nm and 1063.6 nm, corresponding to a frequency difference of about 200 GHz.

Optimizing up-conversion single-photon detectors for quantum key distribution.

High-performance single-photon detectors (SPDs) at 1550-nm band are critical for fiber-based quantum communications. Among many types of SPDs, the up-conversion SPDs based on periodically poled lithium niobate waveguides are of great interest. Combined with a strong pump laser, the telecom single-photons are converted into short wavelength ones and detected by silicon-based SPDs. However, due to the difficulty of precise controlling waveguide profile, the direct coupling between a single-mode fiber and the waveguide is not efficient. Here by utilizing fiber taper with proper diameter, optimal mode-matching is achieved and coupling efficiency up to 93% is measured. With an optimized design, a system detection efficiency of 36% and noise counting rate of 90 cps are realized. The maximum detection efficiency is characterized as 40% with a noise counting rate of 200 cps. Numerical simulation results indicate that our device can significantly improve the performance of QKD and extend the communication distance longer than 200 km.

Entanglement of two quantum memories via fibres over dozens of kilometres.

A quantum internet that connects remote quantum processors1,2 should enable a number of revolutionary applications such as distributed quantum computing. Its realization will rely on entanglement of remote quantum memories over long distances. Despite enormous progress3-12, at present the maximal physical separation achieved between two nodes is 1.3 kilometres10, and challenges for longer distances remain. Here we demonstrate entanglement of two atomic ensembles in one laboratory via photon transmission through city-scale optical fibres. The atomic ensembles function as quantum memories that store quantum states. We use cavity enhancement to efficiently create atom-photon entanglement13-15 and we use quantum frequency conversion16 to shift the atomic wavelength to telecommunications wavelengths. We realize entanglement over 22 kilometres of field-deployed fibres via two-photon interference17,18 and entanglement over 50 kilometres of coiled fibres via single-photon interference19. Our experiment could be extended to nodes physically separated by similar distances, which would thus form a functional segment of the atomic quantum network, paving the way towards establishing atomic entanglement over many nodes and over much longer distances.

Color Erasure Detectors Enable Chromatic Interferometry.

By engineering and manipulating quantum entanglement between incoming photons and experimental apparatus, we construct single-photon detectors which cannot distinguish between photons of very different wavelengths. These color-erasure detectors enable a new kind of intensity interferometry, with potential applications in microscopy and astronomy. We demonstrate chromatic interferometry experimentally, observing robust interference using both coherent and incoherent photon sources.

Comparative study on six alkaloids in Aconiti Lateralis Radix Praeparata and Aconiti Radix in Jiangyou of Sichuan Province based on multivariate statistical analysis / 中草药

Objective: To establish a UPLC method for the simultaneous determination of benzoylmesaconitine, benzoylaconitine, benzoylhypaconitine, mesaconitine, hypaconitine and aconitinein Aconiti Lateralis Radix Praeparata (ALRP) and Aconiti Radix (AR), and to compare the content difference of six alkaloids in the samples with multivariate statistical analysis. Methods Alkaloids in ALRP and AR were extracted with 0.05 mol/mL hydrochloric acid solution by ultrasonic extraction. The UPLC method was performed on a BEH C18 (100 mm × 2.1 mm, 1.7 μm) through a gradient elution of acetonitrile and water at a flow rate of 0.1 mL/min with column temperature at 35 ℃. The injection volume was set at 4.0 μL, and the detection wavelength was set at 235 nm. Difference significance analysis, activity ratio analysis, toxic constituents index analysis, correlation analysis, hierarchical cluster heatmap analysis, principal component analysis, and TOPSIS analysis were used for data processing to comprehensively evaluate the quality of ALRP and AR. Results The method was in accordance with the regulations. Compared with the content of six alkaloids in ALRP and AR, significant difference existed in mesaconitine, benzoylhypaconitine, aconitine, and monoester diterpenoid alkaloids (MDAs); Significant difference existed in benzoylmesaconitine and benzoylaconitine; There were no significant difference in hypaconitine and diester-diterpenoid alkaloids (DDAs). Taking the six alkaloids as indexes, the sample No. 15 of ALRP was the best in quality and the samples No. 7 of AR was the best in quality. Conclusion The established method is simple, accurate and reliable with good precision, repeatability and stability, which can be used for the simultaneous determination of six alkaloids in ALRP and AR. It is much more accurate and convenient to conduct the quality evaluation by using activity ratio, toxic constituents index and multivariate statistical analysis. The study could provide a reference for improving analysis and determination of ester-type alkaloids in ALRP and AR in ChP, and providing a reference for quality control and evaluation of ALRP and AR.

Determination and multivariate statistical analysis of four nucleosides in Aconiti Lateralis Radix praeparata and Aconiti Radix in Jiangyou of Sichuan Province / 中草药

Objective To establish a UPLC method for the simultaneous determination of uracil, adenosine, guanosine, and uridine in Aconiti Lateralis Radix Praeparata (ALRP) and Aconiti Radix (AR), and to compare the content difference of four nucleosides in the samples based on multivariate statistical analysis. Methods Nucleosides in ALRP and AR were extracted with purified water by ultrasonic extraction. The UPLC method was performed on a BEH C18 (100 mm × 2.1 mm, 1.7 μm) through a gradient elution of acetonitrile and water at a flow rate of 0.2 mL/min with column temperature at 30 ℃. The injection volume was set at 4.0 μL, and the detection wavelength was set at 260 nm. Difference significance analysis, hierarchical cluster heatmap analysis, principal component analysis, and TOPSIS analysis were used for data processing to comprehensively evaluate the quality of ALRP and AR. Results The method was in accordance with the regulations, the quantitative evaluation of uracil, adenosine, guanosine, and uridine was in good linear range (r2 > 0.999 3), and the average recovery was 99.86%, 99.14%, 99.74%, and 98.71% respectively, and the RSDs were all less than 2.0%. Taking the four nucleosides as indexes, the samples No. 18 of ALRP and the samples No. 23 of AR were the best in quality. Conclusion The established method is simple, accurate, and reliable with good precision, repeatability, and stability, which can be used for the simultaneous determination of four nucleosides in ALRP and AR, and it might provide the scientific basis for the study of water-soluble constituents in ALRP and AR.

1.064-µm-band up-conversion single-photon detector.

Based on the technique of periodically poled lithium niobate waveguide, up-conversion single-photon detection at 1.064-µm is demonstrated. We have achieved a system photon detection efficiency of 32.5% with a very low noise count rate of 45 counts per second by pumping with a 1.55-µm-band single frequency laser using the long-wavelength pumping technique and exploiting volume Bragg grating as a narrow band filter. Replacing the volume Bragg grating with a combination of adequate dielectric filters, a detection efficiency of up to 38% with a noise count rate of 700 counts per second is achieved, making the overall system stable and practical. The up-conversion single-photon detector operating at 1.064 µm can be a promising robust counter and find usage in many fields.

Integrated four-channel all-fiber up-conversion single-photon-detector with adjustable efficiency and dark count.

Up-conversion single photon detector (UCSPD) has been widely used in many research fields including quantum key distribution, lidar, optical time domain reflectrometry, and deep space communication. For the first time in laboratory, we have developed an integrated four-channel all-fiber UCSPD which can work in both free-running and gate modes. This compact module can satisfy different experimental demands with adjustable detection efficiency and dark count. We have characterized the key parameters of the UCSPD system.

GPIbα reflects the development and progress of the patients with severe preeclampsia.

UNLABELLED: Preeclampsia (PE) is a pregnancy-specific syndrome that occurs in a previously normotensive woman. Some data suggested that the activation parameters of platelets in preeclampsia. The aim of this study is to determine whether the levels of GPIbα and GPIIb for patients with preeclampsia were enhanced after cesarean section. In this study, detecting levels of GPIbα and GPIIb by flow cytometry (FCM). The venous blood of 48 severe preeclampsia women, 16 mild preeclampsia and 22 normotensive women, were collected before operation and 72 hours after the operation. Blood samples were obtained also from 20 non-pregnant women. RESULTS: The level of GPIbα of the normotensive pregnancy was lower than the control group, but there was no significance (P > 0.05). The level of GPIbα of the severe preeclampsia group was much lower than other groups (P < 0.01). In the severe preeclampsia group, the level of GPIbα of postoperative patients was higher than preoperative patients (P < 0.01). There was no significance of GPIIb levels between each group (P > 0.05). In conclusion, GPIbα was an important index of reflecting the change of severe preeclampsia. Detecting the levels of GPIbα plays an important role in observing the development of this disease and guiding clinical treatment.

Contrasted study on pharmacokinetics of Tibetan medicine Renqing Mangjue compatible with Zuota / 中国中药杂志

To provide insights into the mechanism for the attenuate-synergistic effect of Zuota to Tibetan medicine Renqing Mangjue, a contrasted study was carried out on the pharmacokinetics of brucine and strychnine in mice plasm, which are active and toxicant ingredient in the Tibetan medicine Renqing Mangjue. LC-MS/MS was used to detect simultaneously the concentrations of brucine and strychnine in mice plasm at-different time intervals after administration parallelly and randomly, and the pharmacokinetic software Kinetica 5. 0 was selected to non-compartmental analysis (NCA) for data, and statistical analysis software SPSS 19. 0 was used for significance test on the pharmacokinetic parameters. A reliable LC-MS/MS method was established for the determination of brucine and strychnine in blood plasma, which are consistent with the requirements of the preclinical pharmacokinetic study confirmed by the methodology. The linear concentration ranges of brucine and strychnine were 0.301-104.4 µg · L(-1) (r = 0.999 5) and 0.305-106 µg · L(-1) (r = 0.999 7), respectively; The intra-day and inter-day variable coefficients were both less than 10.0% with good precision; The average extraction recoveries of brucine and strychnine were 116.23% and 112.82%, and RSD were 3.2% and 2.3% separately;The average matrix effects of brucine and strychnine were 122.48% and 116.36%, and RSD were 7.7% and 4.4%, respectively. The pharmacokinetic results showed that AUCtot of brucine and strychnine in Zuota group were both increased remarkably (P < 0.05), and the Cmax of brucine in Zuota group was about 5.25-fold higher than that of brucine in non-Zuota group (P < 0.05). The Tmax of brucine and strychnine reduced to one-eighth and one-quarter respectively compared with those in Non-Zuota group. In addition, the eliminations of brucine and strychnine in vivo were accelerated after the compatibility of Zuota. A significant difference (P < 0.05) occurred at the MRT0-t, of brucine, while the MRT0-∞ and Lz of strychnine were statistically significant upon the inspection level α = 0.1. It was found that the absorption degree of brucine and strychnine in Zuota group increased in the range of the safe dose (or concentration), while their elimination rates were accelerated, which may be one of the mechanisms for attenuate-synergistic effect of Zuota to Tibetan medicine Renqing Mangjue.

Ultralow noise up-conversion detector and spectrometer for the telecom band.

We demonstrate up-conversion single-photon detection for the 1550-nm telecommunications band using a PPLN waveguide, long-wavelength pump, and narrowband filtering using a volume Bragg grating. We achieve total-system detection efficiency of around 30% with noise at the dark-count level of a Silicon APD. Based on the new detector, a single-pixel up-conversion infrared spectrometer with a noise equivalent power of -142 dBm Hz(-1/2) was demonstrated, which was as good as a liquid nitrogen cooled CCD camera.