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Introduction Antenatal depression is common, but most women with the condition choose to remain untreated. The Apgar score, an important indicator of newborn health, has been reported to be influenced by antenatal depression; thus, maternal antenatal depression, as reflected by a poor Apgar score, may harm children's health. Aim To conduct a systematic review and meta-analysis to explore whether maternal antenatal depression is associated with the neonatal Apgar score. Methods We registered the protocol for this study with PROSPERO (CRD42019137585). We searched PubMed, Embase, Web of Science, and the Cochrane Library for published papers that reported the association between depression and Apgar score from inception to December 4, 2019. Two reviewers independently screened and selected the studies according to the inclusion and exclusion criteria, and extracted data according to the predesigned table. Stata version 12.0 software was used to analyze data. Results We finally identified 13 studies for inclusion, including a total of 12017 women. We did not find an association between antenatal depression and the 1-minute Apgar score of neonates (mean difference= -0.03, 95% CI= -0.15–0.09) or the risk of a low Apgar score (OR=1.82, 95% CI=0.51 to 3.13). We found that antenatal depression increased the risk of a low Apgar score at 5 minutes (OR= 1.91, 95% CI= 1.23–2.59), but the association between the 5-minute Apgar score and antenatal depression was not significant (mean difference= -0.001, 95% CI= -0.07–0.07). The results of the subgroup analyses also indicated that there was no association between the 5-minute Apgar score and antenatal depression. Conclusions Antenatal depression increased the risk of a low 5-minute Apgar score; however, we did not find a difference in the mean and distribution of neonatal Apgar scores of mothers with depression and mothers without depression.

Letrozole, an aromatase inhibitor that blocks estrogen synthesis by inhibiting the final step of the estrogen biosynthetic pathway, has been used in the applications of a wide range of infertility settings. It has been more than 20 years since the initial clinical trial of letrozole for ovulation induction. In light of the accumulating clinical and basic evidence, the efficacy and safety of letrozole have been identified. This mini review focuses on our current knowledge of the applications and mechanisms of letrozole for female infertility and various questions are put forward about how letrozole could be more effectively used.

ObjectiveTo investigate the factors that influence luteal phase short-acting gonadotropin-releasing hormone agonist (GnRH-a) long protocol and GnRH-antagonist (GnRH-ant) protocol on pregnancy outcome and quantify the influence. About the statistical analysis, it is not correct for the number of gravidities.MethodsInfertile patients (n = 4,631) with fresh in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) and embryo transfer were divided into GnRH-a long protocol (n =3,104) and GnRH-ant (n =1,527) protocol groups and subgroups G1 (EMT ≤7mm), G2 (7 mm 10 mm) according to EMT on the trigger day. The data were analyzed.ResultsThe GnRH-ant and the GnRH-a long protocols had comparable clinical outcomes in the clinical pregnancy, live birth, and miscarriage rate after propensity score matching. In the medium endometrial thickness of 7–10 mm, the clinical pregnancy rate (61.81 vs 55.58%, P < 0.05) and miscarriage rate (19.43 vs 12.83%, P < 0.05) of the GnRH-ant regime were significantly higher than those of the GnRH-a regime. The EMT threshold for clinical pregnancy rate in the GnRH-ant group was 12 mm, with the maximal clinical pregnancy rate of less than 75% and the maximal live birth rate of 70%. In the GnRH-a long protocol, the optimal range of EMT was >10 mm for the clinical pregnancy rate and >9.5 mm for the live birth rate for favorable clinical outcomes, and the clinical pregnancy and live birth rates increased linearly with increase of EMT. In the GnRH-ant protocol, the EMT thresholds were 9–6 mm for the clinical pregnancy rate and 9.5–15.5 mm for the live birth rate.ConclusionsThe GnRH-ant protocol has better clinical pregnancy outcomes when the endometrial thickness is in the medium thickness range of 7–10 mm. The optimal threshold interval for better clinical pregnancy outcomes of the GnRH-ant protocol is significantly narrower than that of the GnRH-a protocol. When the endometrial thickness exceeds 12 mm, the clinical pregnancy rate and live birth rate of the GnRH-ant protocol show a significant downward trend, probably indicating some negative effects of GnRH-ant on the endometrial receptivity to cause a decrease of the clinical pregnancy rate and live birth rate if the endometrial thickness exceeds 12 mm.

The structural transition of methane-ethane gas hydrates is generally observed during the forming process; however, it has seldom been reported during the dissociation process. Study on the dissociation behavior of methane-ethane hydrate below ice point has important implications on gas storage and transportation. It was also be helpful for the natural gas hydrate production by depressurization in permafrost zones. The dissociation of a series of methane-ethane hydrate samples at atmospheric pressure and temperatures below ice point (272.15–269.15 K) was performed, and the influence of gas composition and temperature on the structural transition was examined using in situ Raman spectroscopy. The hydrate structures were found to transition from structure I to structure II over a methane composition range of 50–68 mol%. The hydrates remained as sI or sII type compounds, and no structural transition occurred during the dissociation when the methane content in methane-ethane gas mixture was decreased to a certain amount (

BackgroundThe risk of spontaneous abortion in patients with polycystic ovary syndrome (PCOS) undergoing assisted reproductive treatment (ART) is higher than that in patients without PCOS, however, no definitive risk factors have been confirmed to associate with the high spontaneous abortion rate in PCOS patients undergoing ART. This study was performed to assess the impact of relevant risk factors on spontaneous abortion in patients with PCOS. Clinical questions were formulated and organized according to the PICOS principle.MethodsA systematic review and meta-analysis were conducted on all published studies on PCOS and spontaneous abortion in Embase, PubMed, Web of Science and Cochrane Library. Related risk factors included body mass index (BMI), age, insulin resistance (IR), hyperandrogenism, and chromosome aberrations. All patients were diagnosed as PCOS using the Rotterdam criteria. The primary endpoint was miscarriage and live birth rate. Fixed-effect models were used to analyze homogeneous data, and subgroup and sensitivity analyses were performed on heterogeneous data. The source of heterogeneity was evaluated, and the random effect model was used to summarize the heterogeneity.ResultsAmong 1836 retrieved articles, 22 were eligible and included in the analysis with 11182 patients. High BMI (OR = 1.48, 95% CI [1.32, 1.67], MD = 1.35, 95% CI [0.58,2.12]) and insulin resistance (MD = 0.32, 95% CI [0.15, 0.49]) were associated with an increased risk of spontaneous abortion in PCOS patients undergoing ART. Older age (OR = 0.29, 95% CI [0.29, 0.44], MD = 2.01, 95% CI [0.04, 4.18]), embryonic chromosomal aberrations (OR = 0.75, 95%CI [0.31,1.77]), and hyperandrogenism (MD = 0.10, 95% CI [- 0.02, 0.22]) were not associated with the high spontaneous abortion rate in patients with PCOS. A subgroup analysis of BMI showed that there was no statistically significant difference in the effect between overweight and obesity on spontaneous abortion in PCOS patients undergoing ART (OR = 1.34, 95% [0.97, 1.85]).ConclusionHigh BMI and insulin resistance are two risk factors for an increased risk of spontaneous abortion in PCOS patients undergoing ART, and losing weight and mitigating insulin resistance may decrease the spontaneous abortion rate in these patients undergoing ART.

This study was to retrospectively analyze the effect of the age of embryos transfer and oocyte retrieval on the clinical pregnancy outcome in patients with simple tubal factor infertility (TFI) who received frozen-thawed embryo transfer. Patients (n = 3619) with simple TFI who underwent in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) frozen-thawed embryo transfer at our hospital were enrolled. Univariate logistic regression analysis, categorical multivariate logistic regression analysis, curve fitting and threshold effect analysis were performed. Age of embryo transfer was a significant (P

Nowadays, the combination of natural gas hydrates exploitation and CO2 storage is considered of excellent application. In this work, we explored reservoir reformation technology to enhance gas recovery from the unsealed water-saturated hydrate-bearing deposits in a large-scale tridimensional simulator. Firstly, recurrent CO2 injection into the overburden was to gradually form CO2 hydrate and reduce its permeability. Then traditional depressurization operations were conducted to compare the influences of overburden thickness and additional reservoir reformation on the evolution of pressure distribution and the gas/water production. The results showed that reservoir reformation could effectively improve the mining efficiency, reaching ∼2–4 times of gas production and ∼3–5 times of gas–water ratio compared with the direct depressurization. After a long-term reformation, CH4 recovery ratio was increased from 24.5% to 84.9%. Additionally, we further demonstrated the complete spatiotemporal evolution mechanism of the initial CH4 hydrate and artificial overlying CO2 hydrate during depressurization. A large amount of CO2 was ultimately stored in the depleted reservoir in the form of CO2 hydrate and the CO2 storage ratio was up to 79.5%. Therefore, this reservoir reformation approach is greatly promising for high-efficient and safe exploitation of marine hydrate and CO2 storage.

Traditional lidar sensitivity is not up to the requirements in detecting small long-range targets with weak echo signals. Due to the limitation by the background noise of sunlight and complex climate, the high sensitivity detection cannot be realized by a photon counting lidar with Geiger-mode Avalanche Photodiode Detector (Gm-APD). In this paper, a new system is proposed to improve the performance of photon counting lidar ranging based on two-dimensional modulation. The new system uses two modulation methods to modulate the transmitted signal, which are chirp modulation and photon orbital angular momentum modulation. Chirped modulation is used to adjust the transmitted signal waveform in the frequency domain, and the detection performance improvement of Gm-APD can be improved with response probability correction. Photon orbital angular momentum modulation is used to adjust the transmitted signal waveform in the spatial domain, which is used to filter out background noise. The simulation results show that two-dimensional modulation is independent and do not interfere with each other. Comparing with the traditional lidar, the detection probability increased by 52%; the SNR can be increased by up to 115%, the range accuracy can be up to two-thirds of the traditional range accuracy (means increased by 32%). The new system achieves high sensitivity detection in complex environment.

CO2 replacement is considered as a promising method for the simultaneous development of natural gas hydrate and CO2 sequestration. The addition of small molecular gases, such as N2 and H2, into the injected gas can increase the gas recovery ratio and prevent CO2 liquefaction. Based on previous studies, this work presents methane hydrate exploitation using the CO2/H2 continuous injection-production mode. The mechanism combines gas sweep with CH4/CO2 replacement. A series of experiments were carried out to optimize the injected gas composition and flow rate, which have a significant effect on the rate of CH4 hydrate decomposition, amount of CO2 sequestration, and cost. The compositions of the injected gases had little effect on the recovery rate when a relatively higher flow rate was employed. A balance between CH4 production and CO2 sequestration was established when the CO2 mole fraction was slightly

Traditional lidar is not effective in detecting small long-range targets with weak echo signals. Geiger-mode Avalanche Photodiode (Gm-APD) single photon detector has super high sensitivity. By adding photon orbital angular momentum modulation module, a photon-counting chirped amplitude modulation lidar with high sensitivity ranging function is designed. Based on the characteristics of photon orbital angular momentum space transmission, a special demodulation method is used to realize the spatial separation of noise and signal. The above scheme achieves the goal of high sensitivity ranging detection. The simulation results show that the scheme can improve the signal-to-noise ratio of the system effectively and realize the high-sensitivity ranging function of small target in long distance.

CH4 hydrate have been considered as the future clean energy resource. Recovery of CH4 from natural gas hydrates by CO2 replacement is a promising method for energy harvest and CO2 sequestration. Field production tests have proved the feasibility of gas production by CO2 replacement in the permafrost region. However, most of the hydrate reservoirs are located at marine conditions where pressure and temperature conditions are not favorable for the replacement process. In this work, we identified a possible marine condition, where mixed hydrates could potentially form. We investigated the technical feasibility of CH4 recovery by a depressurization process followed by the injection of CO2-N2 gas. To quantify the dynamic behavior of mixed hydrates formation and dissociation, we developed a numerical method to estimate the phase partitioning during the replacement process. The effects of mixed gas compositions in the reactor on the replacement efficiency were investigated. Our experimental results showed that rapid co-growth of mixed hydrates occurs when the injected gas composed of a lower N2 concentration (

A novel natural gas hydrate production method combined with methane steam reforming and CO2/H2 replacement was proposed to improve the replacement effect and reduce the cost of later gas separation, in which the role of H2 is to decrease the partial pressure of methane in gas phase and help to break the methane hydrate stability. After preparing representative hydrate sediment samples, we conducted a series of experiments to study the characteristics of gas production by the CH4-CO2/H2 replacement method. For the composition of CO2 and H2 in the feed gas, an increase in the mole fraction of H2 would result in a higher accumulative gas production ratio during the gas sweep and replacement stages but decrease the CO2 sequestration ratio, which refers to the amount of CO2 captured by the hydrate versus the gross CO2 injected into the hydrate layer. On the contrary, an increase in the mole fraction of CO2 in the feed gas would have a higher CO2 sequestration ratio, but would sacrifice both the gas production rate and the accumulative methane production ratio. Notably, when the mole fraction of the CO2 ranges from 55% to 72%, the amount of CO2 trapped into hydrate phase is close to the amount of methane dissociated from hydrate. Although the accumulative gas production ratio is not the highest in this range, it can meet the dual function of CO2 replacement.

Natural gas hydrates samples are rare and difficult to store and transport at in situ pressure and temperature conditions, resulting in difficulty to characterize natural hydrate-bearing sediments and to identify hydrate accumulation position and saturation at the field scale. A new apparatus was designed to study the acoustic properties of seafloor recovered cores with and without hydrate. To protect the natural frames of recovered cores and control hydrate distribution, the addition of water into cores was performed by injecting water vapor. The results show that hydrate saturation and types of host sediments are the two most important factors that govern the elastic properties of hydrate-bearing sediments. When gas hydrate saturation adds approximately to 5–25%, the corresponding P-wave velocity (Vp) increases from 1.94 to 3.93 km/s and S-wave velocity (Vs) increases from 1.14 to 2.23 km/s for sandy specimens; Vp and Vs for clayey samples are 1.72–2.13 km/s and 1.10–1.32 km/s, respectively. The acoustic properties of sandy sediments can be significantly changed by the formation/dissociation of gas hydrate, while these only minorly change for clayey specimens.

Objective To quantitatively analyze distribution characteristics of sweat gland nerve fibres (SGNF) in normal Chinese individuals for obtaining a reference for early diagnosis of peripheral neuropathy. Patients and methods Skin biopsy samples were collected from 192 normal Chinese individuals and divided into six, four and two groups according to anatomic sites, age and gender, respectively. SGNF morphology was observed and SGNF density (SGNFD) was determined. Results There was a significant difference in SGNFD among different anatomic sites, age and gender. A degressive tendency was observed from proximal to distal anatomic sites. SGNFD was the lowest in subjects in the 21–40-year-old age group, but was the highest in subjects in the >61-year-old age group. Overall, SGNFD fluctuated with age. SGNFD in males was significantly higher than that in females. Conclusions Distribution characteristics of SGNF in normal individuals may serve as a reference for early diagnosis of nerve fibre damage.

IntroductionThis study aimed to investigate the effect of androgen on bone metabolism in hyperuricemic rats.Material and methodsForty male Wistar rats were randomly divided into four groups: sham operation group, simple hyperuricemic group, hyperuricemic castration group, and simple castration group. A rat model of chronic hyperuricemia was established using potassium oxonate and ethambutol. Blood was sampled from the vena angularis at week 0, 4, 6, 8 and 12 after surgery to detect for uric acid, calcium, phosphorus and alkaline phosphatase, and investigate the effect of androgen on bone metabolism in hyperuricemic rats.ResultsFrom the 4th week, compared with the sham operation group, the differences in uric acid levels between the simple hyperuricemic group and hyperuricemia castration group were statistically significant (p < 0.05), suggesting the successful establishment of the model of hyperuricemia. At the 6th week, uric acid levels decreased in the two hyperuricemic groups, and the difference from the sham operation group decreased (p = 0.05), showing that the modeling method had deteriorated. At the 8th week, the differences in uric acid levels between the two castration groups and sham operation group were statistically significant (p < 0.05). At the 12th week, the differences in serum levels of phosphorus between the simple hyperuricemic group and hyperuricemic castration group were statistically significant (p < 0.05).ConclusionsAndrogen can induce bone metabolism changes in rats with hyperuricemia.

The exploitation of unsealed marine hydrate deposits is of greater commercial value, but also more challenging because of the risks of the invading of huge body of sea water and subsidence of the seabed. In this work, we proposed a new method to recover natural gas from the usealed hydrate deposits saturated with water by pressure-retaining gas (CO2 + H2) injection. A series of experimental simulations was performed to prove its feasibility through establishing a highly simulated unsealed marine hydrate-bearing sediments system. The results demonstrated that overlying water invading was almost completely inhibited for the pressure-retaining approach while unimpeded for the simple depressrization process. Further, we designed a temporary depressurization process before gas injection to establish a flow field for gas in the sediments. This combined operation effectively enhanced the migration and spread of the injected gas, eventually increasing gas recovery ratio from 25% to 60% while the produced water/gas ratio remains as low as 12.6 ST kg/m3. Additionally, it is proved that the balance between CO2 sequestered and CH4 recovered could be achieved, which was an excellent support for reservoir stability. The combination method realized a higher CH4 concentration in the produced gas and a lower injection-production ratio, which greatly reduced the costs of gas injection and subsequent treatment of produced gas. For comparison, similar simulation work was also performed with respect to sealed gas-rich hydrate-bearing sediments. Overall, this temporary depressurization aided pressure-retaining gas injection approach is very promising for high efficient and safe exploitation of marine hydrtates.

The relationship between the hydrate-bearing sediments with physical properties such as wave velocity is of importance for the exploration and exploitation of natural gas hydrate. The distribution modes of naturally occurring gas hydrates in sediments are diverse and have significant influence on physical properties of rocks. However, hydrates in homogeneous distribution are in general investigated in laboratory currently. In this work, to simulate the diverse distribution modes of naturally occurring gas hydrates, a novel method to prepare the hydrate-bearing sediments with heterogeneous distribution including layered distribution was proposed by controlling the temperature, water migration, and water saturation distribution. Velocity and amplitude of P-wave are investigated to evaluate the physical properties of hydrate-bearing sediments with homogeneous or heterogeneous distribution. The results showed that the hydrate formation process apparently consists of unconsolidated and consolidated steps according to the amplitude curve. The amplitude of P-wave in the unconsolidated stage increases slowly, while it increases suddenly and rapidly in the consolidated stage. The P-wave velocity of the hydrate deposits with homogeneous distribution is faster than that with heterogeneous distribution when under a same hydrate saturation. This is also verified from the experiments performed on hydrate-bearing sediments with layered distribution, which provided direct evidence and quantification about heterogeneous degree of hydrate distribution in sediment. This difference of the P-wave velocity between heterogeneous and homogeneous hydrate-bearing sediments would provide a guidance in the future development of natural gas hydrate.

Gas injection, as a method for natural gas hydrate exploitation, has attracted much attention, because of its advantages of low energy consumption and non-destructive characteristics. The gas recovery can be significantly enhanced by adding small-molecule gases such as N2 or H2 to the injecting gas mixture. To evaluate the independent effects of the small-molecule gases on the CH4 hydrate decomposition behaviours, the Raman spectroscopy, gas chromatography, and a CCD camera were adopted. The experimental results show that the CH4 decomposition pressure was increased by injection of small-molecule gases such as N2 or H2. The addition of small-molecule gases in the gas phase led to the change of the hydrate phase equilibrium, which made the CH4 hydrate become more unstable. No N2/H2 hydrates Raman peaks were obtained throughout the experimental process, which indicates that the N2/H2 molecules did not enter the hydrate cages and did not participate in the hydrate formation. Moreover, it suggests that the injected small-molecule gases promote the decomposition of CH4 hydrate by changing the fugacity of CH4. H2 has a more significant effect on the decomposition of CH4 hydrate than N2. This is probably due to the larger diffusion coefficient of H2 in the hydrate phase than that of N2. This kind of promotion effect is beneficial to the production of CH4 gas from hydrate.

Lidar based on Geiger-mode Avalanche Photodiode Detector (Gm-APD), also called Gm-APD Lidar for short, has the advantages of the ultra-high sensitivity and ranging accuracy, and therefore it is widely used in the weak signal detection over a long distance. Time-Correlated Single Photon Counting (TCSPC) is a more commonly used signal processing method of Gm-APD Lidar. However, after each avalanche response, Gm-APD needs a certain time to quench avalanche current, which is called the dead time. In the dead time, Gm-APD can't response any signal. This will result in the uneven response by Gm-APD, and the response probability of the front of the echo pulse signal is higher than that of the back of the echo pulse signal. The peak of photon counting results will deviate from the real peak of the echo signal, and this deviation will become larger with the increase of the echo pulse width. In many application environments (for example, underwater, battlefield smoke, fog and dust, etc.), the broadening effect of the echo pulse signal is obvious, and this will seriously impact the ranging accuracy of Gm-APD Lidar. In this paper, an improved method uses the multi-gate detection to response the complete waveform of the echo pulse signal, and thus improves the ranging accuracy of GmAPD due to obtaining more accurate echo pulse peak.

Photon counting lidar based on a single-photon detector has ultrahigh sensitivity and ranging accuracy, and thus it is widely used in remote detection with extremely weak received signal (even less than one photon in each received pulse). In this paper, a novel improved photon counting lidar is proposed and demonstrated. This improved system uses a piecewise statistical method and is able to acquire radial range, velocity, and acceleration of the target without increasing system hardware complexity. An experimental system of principle verification is constructed, and a reflector attached to an electrically controlled transmission belt is used to simulate a moving target. The experimental results show the acquisition of radial range, velocity, and acceleration simultaneously in the case of photon starved scenes.

An intelligent terminal of telemetering, remote control and remote signaling which was capable of all the system operation regarding distant data transmission and monitoring on mobile, was assembled through the application of microcontroller and industrial communication module. Various physical quantities of devices could be measured and text-message transmitted by the designed multi-sensor. a microcomputer control center monitoring all kinds of terminals could be set up. The design can be further applied in Internet of Things.

The development of a large display and can control a variety of compatible lighting control system, the system is suitable for wide range control distance. Can be widely used in modern college park, landscape building, business building and landscaping all buildings, publicity, service, advertising and other large screen and lighting systems. Using large-scale high-speed FPGA technology, Gigabit fiber communication technology, through a multi-level processing and protocol conversion, can be terminal for the different display mode (divided into static, 2 sweep, sweep 4, 8, sweep, sweep five kinds of 16), data in the order, alignment methods, control methods, the preparation of their own in the FPGA, the protocol conversion module, through the software are free to choose set the display terminal type, to achieve 16 control port can be controlled separately different types of display terminal. Control distance up to 5000 meters or more. Effectively address all the original control system can not be compatible, not centralized control, can not share resources and control of the key problems of distance is too short.

Geiger mode avalanche photodiode detector (Gm-APD) possesses the ultra-high sensitivity. Photon counting chirped amplitude modulation (PCCAM) light detection and ranging (lidar) uses the counting results of the returned signal detected by Gm-APD to mix with the reference signal, which makes PCCAM lidar capable of realizing the ultra-high sensitivity, and this is very important for detecting the remote and weak signal. However, Gm-APD is a nonlinear device, different from traditional linear detectors. Due to the nonlinear response of Gm-APD, the counting results of the returned signal detected by Gm-APD are different from those of both the original modulation signal and the reference signal. This will affect the mixing effect and thus degrade the detection performance of PCCAM lidar. In this paper, we propose a response probability correction method. First, the response probability correction model is established on the basis of Gm-APD Poisson probability response model. Then, the response probability correction model is used to adjust the original modulation signal that is used to drive laser, in order to make the counting results of the returned signal detected by Gm-APD better mix with the local reference signal in the same form. Through this method, the detection performance of PCCAM lidar is enhanced efficiently.