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We demonstrate a narrow-linewidth, high side-mode suppression ratio (SMSR) semiconductor laser based on the external optical feedback injection locking technology of a femtosecond-apodized (Fs-apodized) fiber Bragg grating (FBG). A single frequency output is achieved by coupling and integrating a wide-gain quantum dot (QD) gain chip with a Fs-apodized FBG in a 1-μm band. We propose this low-cost and high-integration scheme for the preparation of a series of single-frequency seed sources in this wavelength range by characterizing the performance of 1030 nm and 1080 nm lasers. The lasers have a maximum SMSR of 66.3 dB and maximum output power of 134.6 mW. Additionally, the lasers have minimum Lorentzian linewidths that are measured to be 260.5 kHz; however, a minimum integral linewidth less than 180.4 kHz is observed by testing and analyzing the power spectra of the frequency noise values of the lasers.

Background： Genetic factors are the main cause of early miscarriage. This study aimed to investigate aneuploidy in spontaneous abortion by fluorescence in situ hybridization （FISH） using probes for 13, 16, 18, 21, 22, X and Y chromosomes. Methods： A total of 840 chorionic samples from spontaneous abortion were collected and examined by FISH. We analyzed the incidence and type of abnormal cases and sex ratio in the samples. We also analyzed the relationship between the rate of aneuploidy and parental age, the rate of aneuploidy between recurrent abortion and sporadic abortion, the difference in incidence of aneuploidy between samples from previous artificial abortion and those from no previous induced abortion. Results： A total of 832 samples were finally analyzed. 368 （44.23%） were abnormal, in which 84.24% （310/368） were aneuploidies and 15.76% （58/368） were polyploidies. The first was trisomyl6 （121/310）, followed by trisomy 22, and X monosomy. There was no significant difference in the rate ofaneuploidy in the advanced maternal age group （≥35 years old） and young maternal age group （〈35 years old）. However, the rate oftrisomy 22 and the total rate of trisomies 21, 13, and 18 （the number oftrisomy 21 plus trisomy 13 and trisomy 18 together） showed significantly different in two groups. We found no skewed sex ratio. There was no significant difference in the rate of aneuploidy between recurrent miscarriage and sporadic abortion or between the samples fi＇om previous artificial abortion and those from no previous artificial abortion. Conclusions： Aneuploidy is a principal factor of miscarriage and total parental age is a risk factor. There is no skewed sex ratio in spontaneous abortion. There is also no difference in the rate of aneuploidy between recurrent abortion and sporadic abortion or between previous artificial abortion and no previous induced abortion.

Transabdominal ultrasound (US) at 35-day posttransfer showed monochorionic triplets, each with a heartbeat [Figure 1]a.Figure 1 The first and second pregnancy trimesters proceeded smoothly, but one fetus demonstrated intrauterine distress at 33 weeks of gestation, and three normal baby boys were born at the 33rd week of gestation by cesarean section. [3],[4] Although the mechanisms whereby assisted reproductive technology increases the incidence of MZT remain unclear, an increased incidence of monozygotic multiple pregnancies has been associated with advanced maternal age, ovulation induction, certain IVF culture conditions and prolonged culture, zona pellucida (ZP) micromanipulation such as intracytoplasmic sperm injection, assisted hatching, and FET. [5] The mechanisms may involve hardening of the ZP as a consequence of extended exposure to the culture medium, leading to the development of multifetal plates during blastocyst hatching; an effect of the culture medium on the junctions of the inner cell mass, leading to monochorionic multiple gestations; or manipulation of the ZP triggering splitting of the blastocyst and formation of MZTs through the hole in the ZP during blastocyst expansion.

Galangin, a natural flavonoid product derived from the root of galangal, is emerging as a promising anticancer agent against multiple cancers. Yet, whether it also has antitumor effects on cholangiocarcinoma (CCA) and the underlying mechanism is still unknown. Herein, we demonstrate that galangin exhibits multiple antitumor effects on CCA cells including decreases cell viability; inhibits proliferation, migration, and invasion; and induces apoptosis. Moreover, those phenotypic changes are associated with downregulated microRNA-21 (miR-21) expression. To support, overexpression of miR-21 blocks galangin-mediated antisurvival and metastasis effects on CCA cells. Mechanically, galangin increases the expression of phosphatase and tensin homolog (PTEN), a direct target of miR-21, resulting in decreased phosphorylation of AKT, a protein kinase which plays a critical role in controlling survival and apoptosis. In contrast, overexpression of miR-21 abrogates galangin-regulated PTEN expression and AKT phosphorylation. Taken together, these findings indicate that galangin inhibits CCA cell proliferation and metastasis and induces cell apoptosis through a miR-21-dependent manner, and galangin may provide a novel potential therapeutic adjuvant to treat CCA.

Postoperative nausea and vomiting are typical postsurgical complications. Drug therapy is only partially effective. The goal of our meta-analysis is to systematically evaluate the efficacy and safety of electrical acupoint stimulation for postoperative nausea and vomiting and to score the quality of evidence supporting this concept. PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov were searched from inception to March 19, 2020. Twenty-six studies (2064 patients) were included. Compared with control treatment, electrical acupoint stimulation reduced the incidence of postoperative nausea and vomiting (RR 0.49, 95% CI 0.41 to 0.57, P < 0.001), postoperative nausea (RR 0.55, 95% CI 0.47 to 0.64, P < 0.001) and postoperative vomiting (RR 0.56, 95% CI 0.45 to 0.70, P < 0.001). Electrical acupoint stimulation also reduced the number of patients requiring antiemetic rescue (RR 0.60, 95% CI 0.43 to 0.85, P = 0.004). No differences in adverse events were observed. Subgroup analysis showed that both electroacupuncture (RR 0.58, 95% CI 0.46 to 0.74, P < 0.001) and transcutaneous electrical acupoint stimulation (RR 0.44, 95% CI 0.34 to 0.58, P < 0.001) had significant effects. Electrical acupoint stimulation was effective whether administered preoperatively (RR 0.40, 95% CI 0.27 to 0.60, P < 0.001), postoperatively (RR 0.59, 95% CI 0.46 to 0.76, P < 0.001), or perioperatively (RR 0.50, 95% CI 0.37 to 0.67, P < 0.001). The quality of evidence was moderate to low. Electrical acupoint stimulation probably reduce the incidence of postoperative nausea and vomiting, postoperative nausea, postoperative vomiting, and reduce the number of patients requiring antiemetic rescue, with few adverse events.

AbstractWater waves in coastal areas are generally nonlinear, exhibiting asymmetric velocity profiles with different amplitudes of crest and trough. The behaviors of the boundary layer under asymmetric waves are of great significance for sediment transport in natural circumstances. While previous studies have mainly focused on linear or symmetric waves, asymmetric wave-induced flows remain unclear, particularly in the flow regime with high Reynolds numbers. Taking cnoidal wave as a typical example of asymmetric waves, we propose to use an infinite immersed plate oscillating cnoidally in its own plane in quiescent water to simulate asymmetric wave boundary layer. A large eddy simulation approach with Smagorinsky subgrid model is adopted to investigate the flow characteristics of the boundary layer. It is verified that the model well reproduces experimental and theoretical results. Then a series of numerical experiments are carried out to study the boundary layer beneath cnoidal waves from laminar to fully developed turbulent regimes at high Reynolds numbers, larger than ever studied before. Results of velocity profile, wall shear stress, friction coefficient, phase lead between velocity and wall shear stress, and the boundary layer thickness are obtained. The dependencies of these boundary layer properties on the asymmetric degree and Reynolds number are discussed in detail.Graphical abstract

A new carbon bridged cyclopentadienyl chromium complex of the type [（C5H4）C（CH3）2 CH2（C5H4N）]CrCl2 was prepared by treatment of CrCl3·（THF）3 in THF solution with the lithium salt of ligand containing cyclopentadienyl and pyridyl groups. The chromium complex was characterized by 1H NMR and elemental analysis（EA）, and the crystal structure was determined by X-ray diffraction analysis. Activated by Al（i-Bu）3, the chromium complex displayed a very high activity for methyl methacrylate（MMA） polymerization. After 24 hours,more than 95.5% MMA was converted to polymethyl methacrylate（PMMA） with a viscosity average molecular weight（Wη） of 416000 g·mol-1 at 60 ℃ for MMA/ Al（i-Bu）3 /chromium catalyst molar ratio of up to 2000：20：1. Effects of temperature, molar ratios of MMA/catalyst and catalyst/cocatalyst on the polymerization have been studied. The high conversion of MMA and high molecular weight of PMMA with narrow molecular weight distribution is caused by the unique stable active site formed by the new chromium complex and aluminum cocatalyst.

The ultimate goal of quantum information science is to build a global quantum network, which enables quantum resources to be distributed and shared between remote parties. Such quantum network can be realized by all fiber elements, which takes advantage of low transmission loss,low cost, scalable and mutual fiber communication techniques such as dense wavelength division multiplexing. Therefore high quality entangled photon sources based on fibers are on demanding for building up such kind of quantum network. Here we report multiplexed polarization and timebin entanglement photon sources based on dispersion shifted fiber operating at room temperature. High qualities of entanglement are characterized by using interference, Bell inequality and quantum state tomography. Simultaneous presence of entanglements in multichannel pairs of a 100GHz DWDM shows the great capacity for entanglements distribution over multi-users. Our research provides a versatile platform and moves a first step toward constructing an all fiber quantum network.

[ Objective] The paper was to test the feasibility of embryo transfer technique in pig production. [ Method ] Twenty-four estrus muhiparity Landraee sows provided by Longjing Agricultural Science and Technology Institute were performed embryo transfer surgery, and postoperative effects were observed. [ Result] Totally 11 out of 24 receptor sows were pregnant ; pregnant sows delivered 67 cloned piglets, and the average farrowing rate of sows was approximately 6 piglets/sow. There were 22 mortalities of newborn piglets because of various reasons. [ Conclusion] Embryo transfer technique is an indispensable link in pig production, and an important means of pig breeding and improvement.