Empagliflozin improves cardiac function in rats with chronic heart failure.

The objective of this study is to examine the effect of empagliflozin on cardiac function in rats with chronic heart failure and the possible mechanism. Forty 6-week-old male SD rats were randomly divided into the control group, empagliflozin treatment group, and sham-operated group. SD rats in the control group and empagliflozin treatment group were subjected to ligation of the anterior descending coronary artery to induce an acute myocardial infarction model. SD rats in the sham-operated group were only subjected to threading of the anterior descending branch of the coronary artery without ligation. On the second day after surgery, the control group and sham operation group were given physiological saline by gavage, while the empagliflozin treatment group was given empagliflozin (30 mg/kg/day) by gavage. Sixteen weeks later, cardiac function, intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), serum brain natriuretic peptide, hypersensitive C-reactive protein (hs-CRP), iNOS expression levels, and myocardial morphological changes were observed. Compared with that in the control group, heart function in the empagliflozin-treated group was significantly improved, MMP was increased, intracellular ROS levels were decreased, and NT-proBNP and hs-CRP were significantly reduced, and HE staining showed that the cell oedema was less than that in the control group, tissue arrangement was more orderly, and iNOS expression was inhibited. Empagliflozin can improve cardiac function in rats with chronic heart failure, and the mechanism may involve inhibiting inflammation, reducing myocardial oxidative stress, and improving myocardial fibrosis.

The Effect of Mn, Al Doping on the CO2 Hydrogenation Performance of CaCO3 -Supported Fe-Based Catalysts.

With increasingly serious environmental problems caused by the greenhouse effect, it has also become essential to reduce the concentration of CO2 in the atmosphere. In this paper, CaCO3 -supported Fe-based catalysts doped with Mn, Al, and K are prepared by a straightforward method and used for CO2 hydrogenation. The fresh and spent catalysts were characterized by SEM-EDS, BET, TG, CO2 -TPD, XRD, and XPS. The experimental results show that the highest CO2 conversion rate of Fe10Mn2Al10Ca is 35.99 %, the maximum FTY value is 293.98 µmolCO2 ⋅ g Fe - 1 ${{\rm{g}}_{{\rm{Fe}}}^{ - 1} }$ ⋅ s-1 , the maximum O/P value is 6.61, and the lowest CO selectivity is 32.21 %. At the same time, according to the characterization results, the doping of Mn and Al increased the Fe3 O4 /FeCx ratio. As the Fe3 O4 /FeCx ratio increases, the proportion of short-chain hydrocarbons (CH4 , C2-4 ) in the products increases, and the proportion of long-chain hydrocarbons (C5+ ) decrease. Therefore, the co-doping of Mn and Al promotes the conversion of CO and reduces its selectivity, and promotes the formation of light olefins. Finally, it is hoped that this study can provide a reference for further research on CaCO3 -supported Fe catalysts.

The Effect Of Ca Doping On The CO2 Hydrogenation Performance Of CaxZn10-xFe20 Catalysts (x=0, 0.5, 1 and1.5).

In this paper, CaxZn10-xFe20 catalysts were prepared by the co-precipitation method and applied to CO2 hydrogenation. The experimental results show that the CO2 conversion of the catalyst Ca1Zn9Fe20 at a Ca doping amount of 1 mmol can reach 57.91 %, which is 13.5 % more than the CO2 conversion of the catalyst Zn10Fe20. Moreover, the catalyst Ca1Zn9Fe20 has the lowest selectivity for both CO and CH4, with 7.40 % and 6.99 %, respectively. The catalysts were characterized by XRD, N2 adsorption-desorption, CO2 -TPD, H2 -TPR, and XPS. The results demonstrate that the doping of Ca increases the basic sites on the catalyst surface and thus allows the catalyst to adsorb more CO2 to promote the reaction. Besides, the Ca doping amount of 1 mmol can suppress the formation of graphitic carbon on the catalyst surface and prevent the excess graphitic carbon from covering the active site Fe5 C2 .

Three-wave differential locking scheme in a 12-m-perimeter large-scale passive laser gyroscope.

Large-scale laser gyroscopes with sufficiently high sensitivity for measurement of the rotation rate of the Earth Ω E are inertial sensors with the capability to provide Earth orientation parameters, i.e., rotation rate and polar motion in near real time. Larger-scale passive resonant gyroscopes (PRGs) theoretically have a lower shot-noise limit. However, the cavity perimeter fluctuations and laser frequency noise become challenges in a passive gyro. In this paper, we introduce a three-wave differential locking scheme for large-scale PRGs, resulting in an in situ measurement of the cavity perimeter with nanometer resolution. Furthermore, the laser frequency noise is effectively suppressed with an additional gain of 30 dB by a double-stage locking system, based on the three-wave differential locking scheme. Finally, the rotation rate resolution of our 3m×3m gyroscope improves to 1.1×10-9 r a d/s over 200 s. The simplicity, robustness, and effectiveness of the locking scheme are important to the long-term operation of large-scale PRGs aiming for applications in the geosciences.

Renal Safety of Sacubitril/Valsartan: A Meta-Analysis of Randomized Controlled Trials.

ABSTRACT: As a first-line therapy, sacubitril/valsartan (S/V) plays a significant role in the treatment of heart failure. However, its effect on renal function is still uncertain. We searched PubMed, EMBASE, the Cochrane Library, and Clinical Trials for randomized controlled trials to evaluate the effect of S/V on renal function in patients. The results are reported as the mean difference, relative ratio, and 95% confidence intervals. A total of 13 randomized controlled trials were included (19,367 patients). Among them, 11 studies focused on patients with heart failure, 1 on patients with acute myocardial infarction, and 1 on patients with chronic kidney disease. We found that fewer worsening renal function events, elevated creatine level events, and severe hyperkalemia events (blood potassium >6.0 mmol/L) occurred in the S/V group than those in the renin-angiotensin-aldosterone system inhibitor (RASi) group. The estimated glomerular filtration rate decreased in both the S/V group and the RASi group, but the change was more obvious in the RASi group. There was no significant difference in hyperkalemia events (blood potassium >5.5 mmol/L) between the 2 groups. Subgroup analysis showed that with the extension of follow-up time (>6 months), worsening renal function events occurred less frequently in the S/V group than in the RASi group. Existing evidence has shown that S/V is superior to RASi in general renal safety. Perhaps with the prolongation of treatment time, the advantages of S/V are more obvious.

Plasma GAS6 predicts mortality risk in acute heart failure patients: insights from the DRAGON-HF trial.

BACKGROUND: Growth arrest-specific 6 (GAS6) is a vitamin K-dependent protein related to inflammation, fibrosis, as well as platelet function. Genetic ablation of GAS6 in mice protects against cardiac hypertrophy and dysfunction. Nonetheless, the association between plasma GAS6 levels and acute heart failure (AHF) patients is still unknown. METHODS: We measured plasma GAS6 concentrations in 1039 patients with AHF who were enrolled in the DRAGON-HF trial (NCT03727828). Mean follow-up of the study was 889 days. The primary endpoint is all-cause death. RESULTS: In total, there were 195 primary endpoints of all-cause death and 135 secondary endpoints of cardiovascular death during the mean follow-up duration of 889 days. The higher levels of GAS6 were associated with higher rates of all-cause and cardiovascular death (P < 0.05). Baseline plasma GAS6 levels were still strongly correlated with clinical outcomes in different models after adjustment for clinical factors and N-terminal pro-brain natriuretic peptide (NT-proBNP, P < 0.05). GAS6 could further distinguish the risks of clinical outcomes based on NT-proBNP measurement. CONCLUSION: Elevated plasma GAS6 levels were associated with an increased risk of all-cause and cardiovascular death in patients with AHF. Trial registration NCT03727828 (DRAGON-HF trial) clinicaltrials.gov.

[Observation of effect of Wu Yun Liu Qi on reproductive hormones in varicocele patients].

Objective： To observe roproductive hormone levels in varicocele patients during a cycle (6 years) of Wu Yun Liu Qi, and explore whether the cycle had effect on the roproductive hormone levels. Methods： Data of roproductive hormone levels in varicocele patients from 2015 to 2020 were analyzed retrospectively. FSH、LH、T、PRL、E2 levels and T/E2 ratio were compared among the six years. According to Chinese sexagenary cycle heavenly stems and earthly branches of each year from 2015 to 2020 its yunqi characteristics were determined. Results: Totally data of 848 cases of varicocele patients were collected from 2015 to 2020. Among which, in 2015 (Yiwei year) there were 57 cases, in 2016 (Bingshen year) 83 cases, in 2017 (Dingyou year ) 133 cases, in 2018(Wuxu year) 156 cases, in 2019(Sihai year) 274 cases, and in 2020(Gengzi year) 145 cases. The levels of FSH、LH、PRL、T were not diferrent statistically from the six years except individual year. However, the level of E2 in 2016 when the Yunqi was Shao Yang Xiang Huo Si Tian and Jue Yin Feng Mu Zai Quan obviously higher than other years excpet 2018( All P< 0.05). And T/E2 ratio was lower in 2016 than other years except 2018 and 2020( All P< 0.05). Conclusions: Shi Xiang factors of Wu Yun Liu Qi had effect on roproductive hormone levels in varicocele patients, showing by higher E2 level in Yinshen year when the Shi Xiang factors may have bad effect on human fertility.

Dual crosslinking of folic acid-modified pectin nanoparticles for enhanced oral insulin delivery.

Pectin-based drug delivery systems hold great potential for oral insulin delivery, since they possess excellent gelling property, good mucoadhesion and high stability in the gastrointestinal (GI) tract. However, lack of enterocyte targeting ability and premature drug release in the upper GI tract of the susceptible ionic-crosslinked pectin matrices are two major problems to be solved. To address these issues, we developed folic acid (FA)-modified pectin nanoparticles (INS/DFAN) as insulin delivery vehicles by a dual-crosslinking method using calcium ions and adipic dihydrazide (ADH) as crosslinkers. In vitro studies indicated insulin release behaviors of INS/DFAN depended on COOH/ADH molar ratio in the dual-crosslinking process. INS/DFAN effectively prevented premature insulin release in simulated GI fluids compared to ionic-crosslinked nanoparticles (INS/FAN). At an optimized COOH/ADH molar ratio, INS/DFAN with FA graft ratio of 18.2% exhibited a relatively small particle size, high encapsulation efficiency and excellent stability. Cellular uptake of INS/DFAN was FA graft ratio dependent when it was at/below 18.2%. Uptake mechanism and intestinal distribution studies demonstrated the enhanced insulin transepithelial transport by INS/DFAN via FA carrier-mediated transport pathway. In vivo studies revealed that orally-administered INS/DFAN produced a significant reduction in blood glucose levels and further improved insulin bioavailability in type I diabetic rats compared to INS/FAN. Taken together, the combination of dual crosslinking and FA modification is an effective strategy to develop pectin nano-vehicles for enhanced oral insulin delivery.

Enhancement in the active site exposure in a porphyrin-based PIL/graphene composite catalyst for the highly efficient conversion of CO2.

Poly(ionic liquid)s (PILs) have gained widespread attention in recent years due to their excellent properties similar to both ionic liquids and polymers. However, their further applications are limited because abundant and flexible ions easily block nanopores in the PIL catalysts, thus blocking the active sites and ultimately leading to decreased catalytic activity. This work reports the synthesis of a PIL/graphene composite catalyst (iPOP-ZnTPy@GNFs) based on an in situ surface preparation strategy, which effectively controlled the particle size and dispersion state of ionic liquids. The iPOP-ZnTPy@GNFs exhibited a larger surface area and more exposed active sites, which intensified the catalytic activity in the CO2 cycloaddition reaction with propylene oxide with almost double the reaction rate as compared to that of iPOP-ZnTPy-2 at 100 °C and S/C = 1000. As expected, the iPOP-ZnTPy@GNF catalyst efficiently converted epoxides to cyclic carbonates at room temperature or atmospheric pressure, which can significantly reduce the process cost. In addition, iPOP-ZnTPy@GNFs exhibited excellent broad substrate scope, catalytic diversity, and remarkable reusability. The reaction mechanism of CO2 cycloaddition was studied via density functional theory calculations and was validated by experimental findings. This work provides a feasible method for improving the utilization of active sites in PILs as a highly robust catalyst for CO2 cycloaddition and can be further extended to other types of catalytic reactions in practical applications.

Circulating miR-19b-3p as a Novel Prognostic Biomarker for Acute Heart Failure.

Background Circulating microRNAs are emerging biomarkers for heart failure (HF). Our study aimed to assess the prognostic value of microRNA signature that is differentially expressed in patients with acute HF. Methods and Results Our study comprised a screening cohort of 15 patients with AHF and 5 controls, a PCR-discovery cohort of 50 patients with AHF and 26 controls and a validation cohort of 564 patients with AHF from registered study DRAGON-HF (Diagnostic, Risk Stratification and Prognostic Value of Novel Biomarkers in Patients With Heart Failure). Through screening by RNA-sequencing and verification by reverse-transcription quantitative polymerase chain reaction, 9 differentially expressed microRNAs were verified (miR-939-5p, miR-1908-5p, miR-7706, miR-101-3p, miR-144-3p, miR-4732-3p, miR-3615, miR-484 and miR-19b-3p). Among them, miR-19b-3p was identified as the microRNA signature with the highest fold-change of 8.4 and the strongest prognostic potential (area under curve with 95% CI, 0.791, 0.654-0.927). To further validate its prognostic value, in the validation cohort, the baseline level of miR-19b-3p was measured. During a follow-up period of 19.1 (17.7, 20.7) months, primary end point comprising of all-cause mortality or readmission due to HF occurred in 48.9% patients, while patients in the highest quartile of miR-19b-3p level presented the worst survival (Log-rank P<0.001). Multivariate Cox model showed that the level of miR-19b-3p could independently predict the occurrence of primary end point (adjusted hazard ratio,1.39; 95% CI, 1.18-1.64). In addition, miR-19b-3p positively correlated with soluble suppression of tumorigenicity 2 and echocardiographic indexes of left ventricular hypertrophy. Conclusions Circulating miR-19b-3p could be a valuable prognostic biomarker for AHF. In addition, a high level of circulating miR-19b-3p might indicate ventricular hypertrophy in AHF subjects. Registration URL: https://www.clinicaltrials.gov. Unique Identifier: NCT03727828.

Heart Failure With Mid-range Ejection Fraction: Every Coin Has Two Sides.

This review summarizes current knowledge regarding clinical epidemiology, pathophysiology, and prognosis for patients with HFmrEF in comparison to HFrEF and HFpEF. Although recommended treatments currently focus on aggressive management of comorbidities, we summarize potentially beneficial therapies that can delay the process of heart failure by blocking the pathophysiology mechanism. More studies are needed to further characterize HFmrEF and identify effective management strategies that can reduce cardiovascular morbidity and mortality of patients with HFmrEF.

Vibration Property of a Cryogenic Optical Resonator within a Pulse-Tube Cryostat.

Cryogenic ultrastable laser cavities push laser stability to new levels due to their lower thermal noise limitation. Vibrational noise is one of the major obstacles to achieve a thermal-noise-limited cryogenic ultrastable laser system. Here, we carefully analyze the vibrational noise contribution to the laser frequency. We measure the vibrational noise from the top of the pulse-tube cryocooler down to the experiment space. Major differences emerge between room and cryogenic temperature operation. We cooled a homemade 6 cm sapphire optical resonator down to 3.4 K. Locking a 1064 nm laser to the resonator, we measure a frequency stability of 1.3×10-15. The vibration sensitivities change at different excitation frequencies. The vibrational noise analysis of the laser system paves the way for in situ accurate evaluation of vibrational noise for cryogenic systems. This may help in cryostat design and cryogenic precision measurements.

[Effect of bilateral microsurgical subinguinal varicocelectomy on asthenozoospermia and oligozoospermia: A report of 109 cases].

OBJECTIVE: To investigate the effects of bilateral microsurgical subinguinal varicocelectomy (BMSV) in patients with asthenozoospermia or oligozoospermia. METHODS: Totally 147 patients with male infertility received BMSV from January 2018 to May 2019, of whom 109 had complete data recorded. We retrospectively analyzed the clinical data, including the total sperm count per ejeculate, sperm concentration and sperm motility before and after surgery, and the rate of natural conception achieved during the follow-up. RESULTS: BMSV achieved a total effectiveness rate of 79.00% in improving the percentage of progressively motile sperm (a rise of ≥20%) and a marked effectiveness rate of 70.00% (a rise of ≥50%) in the 100 cases of asthenozoospermia as compared with the baseline, with a mean recovery time of (110.13 ± 37.43) days. Besides, a total effectiveness rate of 74.29% (an increase of ≥20%) and a marked effectiveness rate of 71.43% (an increase of ≥50%) were attained in the improvement of sperm concentration in the 35 cases of oligozoospermia, with a mean recovery time of (117.00 ± 48.79 ) days. A natural conception rate of 30.30% was observed during the follow-up. No severe adverse events occurred postoperatively. CONCLUSIONS: BMSV is significantly effective for the treatment of asthenozoospermia and oligozoospermia.

Efficacy of early initiation of ivabradine treatment in patients with acute heart failure: rationale and design of SHIFT-AHF trial.

AIMS: Elevated heart rate (HR) in heart failure (HF) is associated with worse outcomes, particularly in acute HF (AHF). HR reduction with ivabradine reduces cardiovascular events in HF patients with reduced ejection fraction. The present trial aimed to test the hypothesis that the early HR reduction using ivabradine improves clinical outcomes in patients with AHF. METHODS AND RESULTS: SHIFT-AHF is a prospective, multi-centre, double-blind, randomized, placebo-controlled trial to evaluate the efficacy and safety of ivabradine when adding to standard therapy in AHF patients (SHIFT-AHF). The trial will include 674 AHF patients with left ventricular ejection fraction < 45% and New York Heart Association functional classes III-IV. Participants were enrolled from March 2020 and will be followed up until December 2022. Patients are randomized to treatment with ivabradine or placebo (randomization 1:1). After allocation, the dose of ivabradine is titrated according to HR. Six months' follow-up and three control visits (7, 90, and 180 days after enrolment) are required for every participant. Assessment involves clinical examination, laboratory tests, echocardiography, electrocardiography, heart rhythm, cardiac function, and quality of life. The primary endpoint is a composite of all-cause mortality or re-admission due to worsening HF. Secondary endpoints include the assessments of cardiac remodelling, cardiac functional capacity, and quality of life. CONCLUSIONS: The SHIFT-AHF trial will shed further light on the role of early HR reduction using ivabradine in patients with AHF.

Noise Analysis of a Passive Resonant Laser Gyroscope.

Large-scale laser gyroscopes have found important applications in Earth sciences due to their self-sufficient property of measurement of the Earth's rotation without any external references. In order to extend the relative rotation measurement accuracy to a better level so that it can be used for the determination of the Earth orientation parameters (EOP), we investigate the limitations in a passive resonant laser gyroscope (PRG) developed at Huazhong University of Science and Technology (HUST) to pave the way for future development. We identify the noise sources from the derived noise transfer function of the PRG. In the frequency range below 10-2Hz, the contribution of free-spectral-range (FSR) variation is the dominant limitation, which comes from the drift of the ring cavity length. In the 10-2 to 103Hz frequency range, the limitation is due to the noises of the frequency discrimination system, which mainly comes from the residual amplitude modulation (RAM) in the frequency range below 2 Hz. In addition, the noise contributed by the Mach-Zehnder-type beam combiner is also noticeable in the 0.01 to 2 Hz frequency range. Finally, possible schemes for future improvement are also discussed.

Prognostic value of serum hyponatremia for outcomes in patients with heart failure with preserved ejection fraction: An observational cohort study.

Hyponatremia is a risk factor associated with poor prognosis in patients with heart failure (HF) with reduced ejection fraction. However, whether hyponatremia has a similar role in patients with HF with preserved ejection fraction (HFpEF) has remained controversial. Therefore, the present study aimed to investigate the clinical characteristics and 24-month prognostic profile of a cohort of patients with HFpEF in China. From a registered observational cohort study on 1,027 subjects with HF, 496 patients with HFpEF were included. The association between baseline hyponatremia on admission and 24-month adverse outcomes (including all-cause mortality, re-hospitalization for HF and stroke) was analyzed using logistic regression with the Cox proportional hazards model. Of the 496 patients with HFpEF with a mean age of 72.8 years and proportion of males of 53.0%, 71 patients were diagnosed with hyponatremia. Furthermore, 29 patients (5.8%) were lost to follow-up. The hyponatremia group had lower blood pressure and serum hemoglobin, higher N-terminal pro B-type natriuretic peptide (NT-proBNP) and D-dimer, more patients with a history of atrial fibrillation and a higher proportion of spironolactone and loop diuretic use. According to a multivariate regression analysis, New York Heart Association functional classes III-IV and a serum NT-proBNP level above the median were risk factors for hyponatremia, while higher systolic blood pressure and ß-blocker use were protective factors against hyponatremia. In the Kaplan-Meier analysis, hyponatremia was associated with all-causes of mortality, re-hospitalization for HF and a poor prognosis for patients suffering from strokes (log-rank P<0.05 for all 3 endpoints). On multivariate logistic regression analysis with the Cox proportional hazard model, hyponatremia was an independent predictor of three adverse outcomes [all-cause mortality: Hazard ratio (HR)=1.54, 95% CI=1.07-2.91, P=0.034; re-hospitalization for heart failure: HR=1.28, 95% CI=1.16-2.47, P=0.013; stroke: HR=1.78, 95% CI=1.04-2.89, P=0.016]. Collectively, the present results suggested that hyponatremia on admission was significantly associated with all-cause mortality, re-hospitalization and stroke within 24 months in a cohort of hospitalized patients with HFpEF in China. Thus, hyponatremia should be carefully monitored and frequently adjusted in patients with HFpEF (NCT04062500).

Acute non-traumatic subdural hematoma induced by intracranial aneurysm rupture: A case report and systematic review of the literature.

RATIONALE: Intracranial aneurysm with the first manifestation of acute subdural hematoma (aSDH) is rare in the field of neurosurgery. Usually subarachnoid hemorrhage or intracranial hematoma happens after the rupture of an intracranial aneurysm, whereas trauma is the primary cause of aSDH. PATIENT CONCERNS: Here, we present the case of a 71-year-old woman who presented with spontaneous aSDH with progressive headache and vomiting. DIAGNOSIS: Urgent head computed tomography (CT) identified an aSHD, but the patient had no history of trauma. CT angiography (CTA) identified the cause of the aSDH as rupture of an intracranial aneurysm in the left middle cerebral artery. INTERVENTIONS: Emergent craniotomy with hematoma evacuation was performed. OUTCOMES: Due to prompt diagnosis and appropriate intervention, the patient recovered fully with no disability. LESSONS: This unique case demonstrates that aSDH caused by intracranial aneurysm rupture requires timely identification and appropriate action to prevent adverse outcomes. We performed a comprehensive systematic literature review to examine the etiology and pathogenesis of non-traumatic aSDH. Furthermore, digital subtraction angiography should be considered in patients diagnosed with an aSDH with no known cause.

Intravitreal Injection of Human Retinal Progenitor Cells for Treatment of Retinal Degeneration.

BACKGROUND Retinal degeneration causes irreversible blindness. Human retinal progenitor cells (hRPCs) have the potential to treat retinal diseases. The vitreous cavity is a relatively immune-privileged site that is suitable for stem cell transplantation in the treatment of retinal diseases. This study aimed to evaluate the therapeutic efficacy and safety of intravitreal injection of hRPCs in retinal degeneration therapy. MATERIAL AND METHODS hRPCs were primary-cultured and injected into the vitreous cavity of RCS rats. To determine whether hRPCs formed teratomas in immune-deficient mice, hRPCs at different passages were transplanted into BALB/c-nu mice. The visual function was detected by electroretinography recording. Changes in the outer nuclear layer (ONL) were analyzed by histological testing and cell counting. The protective mechanism was further assessed by cytokine antibody array. RESULTS Intravitreal transplantation of hRPCs maintained retinal function and preserved retinal morphology. Importantly, grafted cells in the vitreous cavity were well tolerated, with no adverse effects. Teratoma was not formed in BALB/c-nu mice after hRPCs transplantation. The number of hRPCs-injected eyes and thickness of ONL in the hRPCs-treated group were higher than those in the untreated group and HBSS injection group. The cytokine antibody array revealed that hRPCs expressed GDF-15, PDGF-AA, EGF, and NT-4. CONCLUSIONS Our findings show that intravitreal injection of hRPCs is effective and safe in protecting photoreceptor cells in RCS rats, but were no longer effective at 12 weeks after transplantation. Moreover, hRPCs released multiple neurotrophic factors that may be involved in treating retinal disease.

Long-term digital frequency-stabilized laser source for large-scale passive laser gyroscopes.

We report on the development of a digitally controlled long-term frequency stabilized ultrastable laser source, which serves as an injection laser to stabilize the perimeter of a 3 m × 3 m heterolithic passive resonant gyroscope. We operate the gyroscope at two different cavity modes to reduce back-scattering coupling disturbance for gyroscope locking. This scheme increases the requirement for the injection laser frequency stability since we are using the wavelength of the laser as the length standard for the heterolithic gyroscope structure. The laser source is digitally locked to an ultrastable high-finesse Fabry-Perot cavity and a femtosecond optical frequency comb referenced to an active hydrogen maser simultaneously. The fractional frequency stability of the locked laser is better than 1.2 × 10-14 for averaging times from 0.1 s to 10 000 s. The short-term frequency stability is limited by the stability of the Fabry-Perot cavity, and the long-term frequency stability is limited by the stability of the frequency comb. The digital locking system enables the laser to run autonomously for weeks and can quickly relock itself within seconds to ensure continuous running of the gyroscope. The digital frequency stabilization technique can also fulfill the requirements of space gravitational waves detection and the next generation space gravity recovery mission.

[Method of Dividing the Value of Soil Heavy Metal Pollution Risk Screening: Using Cd as an Example].

The Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (GB 15618-2018) provides the risk screening value of soil environmental quality in China; however, because of differences in soil composition, and physical and chemical properties in different regions, this value has limitations for certain regions. Based on the limits of pollutants in crops given in the National Food Safety Standards Limits of Pollutants for Foods (GB 2762-2017), and using Cd in the soil of the main farming areas in southeastern Chongqing as an example, the content of the elemental biological effective state was determined for the suggested screening value. This method can provide a reference and method for improving the heavy metal and healthy element thresholds of soils with high or low bioavailability, and that are rich in Se content, among other factors.