Twin-Field Quantum Key Distribution with Local Frequency Reference.

Twin-field quantum key distribution (TFQKD) overcomes the linear rate-loss limit, which promises a boost of secure key rate over long distance. However, the complexity of eliminating the frequency differences between the independent laser sources hinders its practical application. We analyzed and determined the frequency stability requirements for implementing TFQKD using frequency-stabilized lasers. Based on this analysis, we proposed and demonstrated a simple and practical approach that utilizes the saturated absorption spectroscopy of acetylene as an absolute reference, eliminating the need for fast frequency locking to achieve TFQKD. Adopting the 4-intensity sending-or-not-sending TFQKD protocol, we experimentally demonstrated the TFQKD over 502, 301, and 201 km ultralow-loss optical fiber, respectively. We expect this high-performance scheme will find widespread usage in future intercity and free-space quantum communication networks.

Early systemic anticoagulation reduces hospital readmission in acute necrotizing pancreatitis patients: A retrospective cohort study.

BACKGROUND: Early systemic anticoagulation (SAC) is a common practice in acute necrotizing pancreatitis (ANP), and its impact on in-hospital clinical outcomes had been assessed. However, whether it affects long-term outcomes is unknown. This study aimed to evaluate the effect of SAC on 90-day readmission and other long-term outcomes in ANP patients. METHODS: During January 2013 and December 2018, ANP patients admitted within 7 days from the onset of abdominal pain were screened. The primary outcome was 90-day readmission after discharge. Cox proportional-hazards regression model and mediation analysis were used to define the relationship between early SAC and 90-day readmission. RESULTS: A total of 241 ANP patients were enrolled, of whom 143 received early SAC during their hospitalization and 98 did not. Patients who received early SAC experienced a lower incidence of splanchnic venous thrombosis (SVT) [risk ratio (RR) = 0.40, 95% CI: 0.26-0.60, P < 0.01] and lower 90-day readmission with an RR of 0.61 (95% CI: 0.41-0.91, P = 0.02) than those who did not. For the quality of life, patients who received early SAC had a significantly higher score in the subscale of vitality (P = 0.03) while the other subscales were all comparable between the two groups. Multivariable Cox regression model showed that early SAC was an independent protective factor for 90-day readmission after adjusting for potential confounders with a hazard ratio of 0.57 (95% CI: 0.34-0.96, P = 0.04). Mediation analysis showed that SVT mediated 37.0% of the early SAC-90-day readmission causality. CONCLUSIONS: The application of early SAC may reduce the risk of 90-day readmission in the survivors of ANP patients, and reduced SVT incidence might be the primary contributor.

Free-space dissemination of time and frequency with 10-19 instability over 113 km.

Networks of optical clocks find applications in precise navigation1,2, in efforts to redefine the fundamental unit of the 'second'3-6 and in gravitational tests7. As the frequency instability for state-of-the-art optical clocks has reached the 10-19 level8,9, the vision of a global-scale optical network that achieves comparable performances requires the dissemination of time and frequency over a long-distance free-space link with a similar instability of 10-19. However, previous attempts at free-space dissemination of time and frequency at high precision did not extend beyond dozens of kilometres10,11. Here we report time-frequency dissemination with an offset of 6.3 × 10-20 ± 3.4 × 10-19 and an instability of less than 4 × 10-19 at 10,000 s through a free-space link of 113 km. Key technologies essential to this achievement include the deployment of high-power frequency combs, high-stability and high-efficiency optical transceiver systems and efficient linear optical sampling. We observe that the stability we have reached is retained for channel losses up to 89 dB. The technique we report can not only be directly used in ground-based applications, but could also lay the groundwork for future satellite time-frequency dissemination.

Quantum Key Distribution over 658 km Fiber with Distributed Vibration Sensing.

Twin-field quantum key distribution (TFQKD) promises ultralong secure key distribution which surpasses the rate distance limit and can reduce the number of the trusted nodes in long-haul quantum network. Tremendous efforts have been made toward implementation of TFQKD, among which, the secure key with finite size analysis can distribute more than 500 km in the lab and in the field. Here, we demonstrate the sending-or-not-sending TFQKD experimentally, achieving a secure key distribution with finite size analysis over a 658 km ultra-low-loss optical fiber. Meanwhile, in a TFQKD system, any phase fluctuation due to temperature variation and ambient variation during the channel must be recorded and compensated, and all this phase information can then be utilized to sense the channel vibration perturbations. With our quantum key distribution system, we recovered the external vibrational perturbations generated by artificial vibroseis on both the quantum and frequency calibration link, and successfully located the perturbation position in the frequency calibration fiber with a resolution better than 1 km. Our results not only set a new distance record of quantum key distribution, but also demonstrate that the redundant information of TFQKD can be used for remote sensing of the channel vibration, which can find applications in earthquake detection and landslide monitoring besides secure communication.

Immune Dysfunction is Associated with Readmission in Survivors of Sepsis Following Infected Pancreatic Necrosis.

OBJECTIVE: Immunosuppression is common in patients with infected pancreatic necrosis (IPN) and associated with morbidity and mortality. This study aimed to investigate the impact of immune status on mortality and readmission after hospital discharge in patients with IPN-related sepsis. METHODS: In this prospective observational study, eligible adult patients with IPN-related sepsis requiring ICU admission were included. Monocytic human leukocyte antigen DR (mHLA-DR), expression of regulatory T cells (Treg), and neutrophil CD88 (nCD88) were measured on the diagnosis of sepsis, ICU discharge, hospital discharge, and 15, 30, 60 days after hospital discharge. Logistic regression model was used to assess potential risk factors for readmission 60-days within the index discharge. RESULTS: A total of 53 patients were included, 13 died during hospitalization and one withdrew the consent soon after discharge. Among the survivors, a tendency of immune recovery was observed during the consecutive follow-ups, evidenced by the increased expression of mHLA-DR. Sixteen patients (41.03%) were readmitted within 60 days after the index discharge. In the multivariable regression model, APACHE II score when sepsis was diagnosed >9 and mHLA-DR at discharged <14,591 AB/C were found to be independent risk factors affecting readmission. CONCLUSION: Immunosuppression is common in patients with IPN-related sepsis and can persist until two months after discharge. The compromised mHLA-DR level at discharge was associated with readmission within two months after discharge.

Digenic Inheritance and Gene-Environment Interaction in a Patient With Hypertriglyceridemia and Acute Pancreatitis.

The etiology of hypertriglyceridemia (HTG) and acute pancreatitis (AP) is complex. Herein, we dissected the underlying etiology in a patient with HTG and AP. The patient had a 20-year history of heavy alcohol consumption and an 8-year history of mild HTG. He was hospitalized for alcohol-triggered AP, with a plasma triglyceride (TG) level up to 21.4 mmol/L. A temporary rise in post-heparin LPL concentration (1.5-2.5 times of controls) was noted during the early days of AP whilst LPL activity was consistently low (50∼70% of controls). His TG level rapidly decreased to normal in response to treatment, and remained normal to borderline high during a ∼3-year follow-up period during which he had abstained completely from alcohol. Sequencing of the five primary HTG genes (i.e., LPL, APOC2, APOA5, GPIHBP1 and LMF1) identified two heterozygous variants. One was the common APOA5 c.553G > T (p.Gly185Cys) variant, which has been previously associated with altered TG levels as well as HTG-induced acute pancreatitis (HTG-AP). The other was a rare variant in the LPL gene, c.756T > G (p.Ile252Met), which was predicted to be likely pathogenic and found experimentally to cause a 40% loss of LPL activity without affecting either protein synthesis or secretion. We provide evidence that both a gene-gene interaction (between the common APOA5 variant and the rare LPL variant) and a gene-environment interaction (between alcohol and digenic inheritance) might have contributed to the development of mild HTG and alcohol-triggered AP in the patient, thereby improving our understanding of the complex etiology of HTG and HTG-AP.

Increased circulating total bile acid levels were associated with organ failure in patients with acute pancreatitis.

BACKGROUND: Recent studies have shown that bile acids (BAs) are closely related to metabolic and inflammatory diseases. Our study aimed to investigate whether circulating total bile acid (TBA) levels were associated with the severity of acute pancreatitis (AP). METHODS: We retrospectively collected data on patients diagnosed with AP in a tertiary center from 01 January 2014 to 31 December 2016. The highest TBA value during the first 1,2,3,5,7 days after admission was determined as D1, D2, D3, D5, D7 TBAmax. Patients were divided into the high TBA (HTBA) group and the normal TBA (NTBA) group according to whether the TBAmax was ≥10 µmol/L. The prognosis and complications, including death, organ failure (OF) and pancreatic necrosis, were compared between the two groups. Logistic regression analysis and receiving operating characteristic (ROC) curve were used to evaluate the relationship between circulating TBA and organ failure in AP patients. RESULTS: Through stratified analysis of each time period, we found that the incidence of OF in the HTBA group was significantly higher than that in the NTBA group, and the AP severity classification in the HTBA group was more serious than that in the NTBA group. In addition, according to the D7 TBAmax values, the pancreatic necrosis rate, percutaneous catheter drainage (PCD) rate and mortality in the HTBA group were higher than those in the NTBA group. Multivariate regression analysis showed that HTBA (odds ratio (OR), 4.894; P = 0.002) was an independent risk factor for AP complicated with OF, which was verified in the grouping based on D7 TBAmax. ROC analysis revealed that a circulating D7 TBAmax cutoff point of 6.450 umol/L had optimal predictive value for the development of OF in AP patients with an area under the curve of the ROC curve (AUCROC) of 0.777. CONCLUSIONS: The increase of circulating TBA in early stage of AP is independently related to organ failure, which indicates the adverse prognosis of AP patients.

Measurement and control from frequency to phase based on virtual signal reconstruction.

A virtual reconstruction method of directly capturing phase information between different nominal frequency signals, without frequency transformation, is proposed in this paper, building a virtual standard frequency signal whose frequency equals the measured nominal frequency and then making continuous comparison in the measuring gate which is synchronous with multiple periods between the measured signal and the reference frequency signal. Phase variations of the measured signal in every continuous gate are determined, and continuous phase-measuring is implemented. The experimental result verifies this special method for directly processing the phase difference between different nominal frequency signals and realizes a comparison precision of 10-17/day in a wide range.

Intercostal artery damage and massive hemothorax after thoracocentesis by central venous catheter: A case report.

Central venous catheters (CVCs) are widely used in various puncture and drainage operations in intensive care units (ICUs) in recent years. Compared to conventional operating devices, CVC was welcomed by clinicians because of the advantages of easy use, less damage to the body and convenient fixation process. We came across a patient with severe acute pancreatitis (SAP) who developed cardiac arrest due to thoracic cavity massive bleeding 24 h after thoracocentesis with CVC. Thoracotomy surgery was carried out immediately, which confirmed an intercostal artery injury. The patient was discharged from hospital without any neurological complications two months later. Here we report this case to remind all the emergency department and ICU physicians to pay more attention to the complication of thoracic cavity bleeding following thoracocentesis conducted by CVC.

The long-term quality of life in patients with persistent inflammation-immunosuppression and catabolism syndrome after severe acute pancreatitis: A retrospective cohort study.

PURPOSE: To explore clinical characteristics and long-term quality of life (QOL) in severe acute pancreatitis (SAP) patients with persistent inflammation-immunosuppression and catabolism syndrome (PICS). MATERIALS AND METHODS: SAP patients admitted to ICU were eligible for the retrospective cohort study if they needed prolonged intensive care (>14days). Post-ICU QOL was assessed by a questionnaire, including 36-item Short Form Health Survey (SF-36) and record of re-work in a long-term follow-up. RESULTS: 214 SAP patients were enrolled, in which 149 (69.6%) patients met the criteria of PICS. PICS patients had more complications and ICU days compared to non-PICS patients (P<0.001), and their post-ICU mortality was higher (P=0.046). When adjusted for confounders, PICS was independently associated with higher post-ICU mortality (hazard ratio 4.5; 95% CI, 1.2 to 16.3; P=0.024). The 36-item Short Form Health Survey (SF-36) score was lower for PICS group in six subscales (P<0.001). Only 28.8% patients in the PICS group returned to work compared to 60% patients in the non-PICS group (P=0.001) CONCLUSIONS: SAP patients with prolonged ICU stay had a high morbidity of PICS, which was a risk factor for the post-ICU mortality and poor long-term QOL.

[Seroepidemiological survey of Toxoplasma gondii in dogs in Urumqi].

From 2011 to 2012 in Urumqi, blood samples of 308 household dogs and of 110 stray dogs were collected from three pet hospitals and a stray dog shelter, respectively. Serum anti-Toxoplasma gondii IgG was detected by ELISA. The results showed that the overall seropositive rate was 31.8% (133/418). The rate in household dogs and stray dogs was 29.9% (92/308) and 37.3% (41/110), respectively (P>0.05). Among 308 household dogs, the positive rate in males and females was 27.0% (41/152) and 32.7% (51/156), respectively (P>0.05). The seropositive rate in dogs <1 years old, 1-2 years old, and more than 2 years old was 27.1% (32/118), 30.2% (29/96), and 33.3% (31/94), respectively (P>0.05). The results revealed a high seroprevalence of T. gondii infection in dogs in Urumqi.

Epidemiology and risk factor analysis for canine echinococcosis in a Tibetan pastoral area of Sichuan.

OBJECTIVE: To determine the prevalence and evaluate the risk factors of canine echinococcosis based on a field survey of dog infections with Echinococcus granulosus and E. multilocularis in Chalong, Kalong, Dade and Chazha Townships in a district of Ganzi County, Sichuan Province, China. METHOD: Questionnaire associated with the acquisition of canine echinococcosis was administered to dog owners. Stray dogs were examined post-mortem and rectal faeces at necropsy were collected to validate a copro-antigen ELISA. Owned dogs were screened for Echinococcus spp. infection in faeces using the genus specific copro-ELISA and the effectiveness of dog treatment was assessed. Chi-square and one-way ANOVA were used for statistical analysis. RESULTS: The prevalence of Echinococcus spp. infection at necropsy in stray dogs was 60.9% (14/23) in 2000; E. multilocularis infection accounted for 34.8% (8/23) and E. granulosus for 26.1% (6/23). The specificity of the copro-ELISA was 80.0% and the sensitivity was 92.3%, compared with the results at necropsy. Fifty percent of owned dogs (290/580) tested was copro-antigen positive at the beginning of the project in 2000, which decreased to 17% (99/580) in the same cohort of owned dogs after praziquantel treatment (5 mg/ kg) at 6-monthly period from 2003 to 2005. Analysis for risk factors associated with copro-antigen positive dogs showed that the never tethered dogs had a higher rate (40.4%, 65/161) than dogs tethered during the day (32.3%, 109/337), or tethered at night [29.2% (21/72)], or those always tethered [20%(2/10)](P<0.01). Dogs that their owners lacked hydatid transmission knowledge [38.1% (121/318)] and did not have de-worming practice [47.7% (92/193)] had significantly higher copro-antigen positive rate than those dogs that their owners knew relevant knowledge [28.6% (75/262)] and were dewormed regularly [20.4% (79/387)](P<0.05 and P<0.01). There was no correlation between the prevalence and dog sex or age or the varieties of livestock that the owner raised. CONCLUSION: Local dogs show high prevalence with both E. granulosus and E. multilocularis. The copro-ELISA can be used to detect infection of Echinococcus in dogs. Allowing dogs to roam, lack of the basic knowledge of hydatid disease transmission and no de-worming practice for dogs are significant factors for the transmission of canine echinococcosis.