Arm locking using laser frequency comb.

The space-borne gravitational wave (GW) detectors, e.g., LISA, TaiJi, and TianQin, will open the window in the low-frequency regime (0.1 mHz to 1 Hz) to study the highly energetic cosmic events, such as coalescences and mergers of binary black holes and neutron stars. For the sake of successful observatory of GWs, the required strain sensitivity of the detector is approximately 10-21/Hz1/2 in the science band, 7 orders of magnitude better than the state of the art of the ultra-stable laser. Arm locking is therefore proposed to reduce the laser phase noise by a few orders of magnitude to relax the burden of time delay interferometry. During the past two decades, various schemes have been demonstrated by using single or dual arms between the spacecraft, with consideration of the gain, the nulls in the science band, and the frequency pulling characteristics, etc. In this work, we describe an updated version of single arm locking, and the noise amplification due to the nulls can be flexibly restricted with the help of optical frequency comb. We show that the laser phase noise can be divided by a specific factor with optical frequency comb as the bridge. The analytical results indicate that, the peaks in the science band have been greatly reduced. The performance of the noise suppression shows that the total noise after arm locking can well satisfy the requirement of time delay interferometry, even with the free-running laser source. When the laser source is pre-stabilized to a Fabry-Perot cavity or a Mach-Zehnder interferometer, the noise can reach the floor determined by the clock noise, the spacecraft motion, and the shot noise. We also estimate the frequency pulling characteristics of the updated single arm locking, and the results suggest that the pulling rate can be tolerated, without the risk of mode hopping. Arm locking will be a valuable solution for the noise reduction in the space-borne GW detectors. We demonstrate that, with the precise control of the returned laser phase noise, the noise amplification in the science band can be efficiently suppressed based on the updated single arm locking. Not only does our method allow the suppression of the peaks, the high gain, and low pulling rate, it can also serve for full year, without the potential risk of locking failure due to the arm length mismatch. We then discuss the unified demonstration of the updated single arm locking, where both the local and the returned laser phase noises can be tuned to generate the expected arm-locking sensor actually. Finally, the time-series simulations in Simulink have been carried out, and the results indicate a good agreement with the theory, showing that the presented method is reasonable and feasible. Our work could provide a back-up strategy for the arm locking in the future space-borne GW detectors.

Constraining the Symmetron Model with the HUST-2020 Torsion Pendulum Experiment.

The search for dynamically screening the coupling between the scalar field and matter in high-density environment is achievable with the symmetron model. The high-accuracy and short-range gravity experiment is proposed to test the symmetron model. In this Letter, the data of the HUST-2020 torsion pendulum experiment testing the inverse-square law at submillimeter range is analyzed to constrain the symmetron model. The results show that the HUST-2020 experiment is uniquely sensitive to probe the symmetron model with a mass scale of µ=7.2×10^{-3} eV, and the self-coupling parameter λ≲105 is excluded at mass scale M=0.3 TeV. Especially, at the dark energy scale µ=2.4×10^{-3} eV, the constraint at M=1.3 TeV is improved by about 10 times the previous constraints on the torsion pendulum experiment.

Combined Test of the Gravitational Inverse-Square Law at the Centimeter Range.

Experiments measuring the Newtonian gravitational constant G can offer uniquely sensitive probes of the test of the gravitational inverse-square law. An analysis of the non-Newtonian effect in two independent experiments measuring G is presented, which permits a test of the 1/r^{2} law at the centimeter range. This work establishes the strongest bound on the magnitude α of Yukawa-type deviations from Newtonian gravity in the range of 5-500 mm and improves the previous bounds by up to a factor of 7 at the length range of 60-100 mm.

Combined Search for a Lorentz-Violating Force in Short-Range Gravity Varying as the Inverse Sixth Power of Distance.

Precision measurements of the inverse-square law via experiments on short-range gravity provide sensitive tests of Lorentz symmetry. A combined analysis of data from experiments at the Huazhong University of Science and Technology and Indiana University sets simultaneous limits on all 22 coefficients for Lorentz violation correcting the Newton force law as the inverse sixth power of distance. Results are consistent with no effect at the level of 10^{-12} m^{4}.

Combined Search for Lorentz Violation in Short-Range Gravity.

Short-range experiments testing the gravitational inverse-square law at the submillimeter scale offer uniquely sensitive probes of Lorentz invariance. A combined analysis of results from the short-range gravity experiments HUST-2015, HUST-2011, IU-2012, and IU-2002 permits the first independent measurements of the 14 nonrelativistic coefficients for Lorentz violation in the pure-gravity sector at the level of 10^{-9} m^{2}, improving by an order of magnitude the sensitivity to numerous types of Lorentz violation involving quadratic curvature derivatives and curvature couplings.

[Therapeutic effect of baicalin in treatment of renal interstitial fibrosis in rats with unliateral ureteral obstruction and related mechanisms].

OBJECTIVE: To investigate the therapeutic effect of baicalin at different doses administered for different periods of time in the treatment of renal interstitial fibrosis in rats with unliateral ureteral obstruction (UUO) and related mechanisms. METHODS: Sixty-four Sprague-Dawley rats were randomly divided into sham-operation, model, low-dose baicalin, and high-dose baicalin groups, and each group was further randomly divided into 7-day and 14-day groups (n=8 each). Left ureteral ligation was used to establish the rat model of UUO. Hematoxylin and eosin staining was used to observe the pathological changes in the kidney. ELISA was used to measure the serum levels of transforming growth factor-ß1 (TGF-ß1), Notch1, and Jagged1. Immunohistochemistry was used to measure the expression of TGF-ß1 and Notch1. The Pearson correlation analysis was used for correlation analysis. RESULTS: Hematoxylin and eosin staining showed inflammatory cell infiltration and edema in renal interstitium, tubular dilation and structure disorder, degeneration and necrosis of renal tubular epithelial cells, and a basically normal structure of the glomeruli on days 7 and 14 in the model group, and these lesions were alleviated in the low- and high-dose baicalin groups. Compared with the sham-operation group, the model group had a significantly higher serum level of TGF-ß1 and a significantly higher number of TGF-ß1-positive cells in renal tissues on days 7 and 14 (P<0.05). Compared with the model group at the same time points, the high- and low-dose baicalin groups had a significantly lower serum level of TGF-ß1 and a significantly lower number of TGF-ß1-positive cells in renal tissues on days 7 and 14 (P<0.05). The serum level of Jagged1 showed no significant differences between any two groups on days 7 and 14 (P>0.05). The serum level of TGF-ß1 was positively correlated with that of Notch1 (r=0.650, P<0.01), and the serum level of Notch1 was positively correlated with that of Jagged1 (r=0.727, P<0.01). TGF-ß1 level in renal tissues was also positively correlated with the number of Notch1-positive cells (r=0.743, P<0.01). CONCLUSIONS: Baicalin can alleviate renal interstitial fibrosis in UUO rats, probably by inhibiting Notch1 signaling pathway and the expression of TGF-ß1.

[Role of urotensin II gene in the genetic susceptibility to gestational diabetes mellitus in northern Chinese women].

OBJECTIVE: To investigate the relationship between the polymorphism of site rs228648 in urotensin II gene and the genetic susceptibility to gestational diabetes mellitus in northern Chinese women. METHODS: Genotyping was conducted to investigate the polymorphism of site rs228648 (G-A) in urotensin II gene among 70 unrelated gestational diabetes mellitus (GDM) subjects and 70 normal controls. DNA samples isolated from leucocyte of the control and study groups were analyzed for single-nucleotide polymorphisms of the urotensin II gene at positions rs228648 using polymerase chain reaction and restriction analysis. RESULTS: (1) The distribution of genotype frequencies of site rs228648 accorded with Hardy-Weinberg's equation law, being colony representative. (2) The frequency of G allele of site rs228648 was 70.7% in GDM group, significantly higher than that in the control group (57.9%, P < 0.05); and the frequency of A allele of site rs228648 was 29.3% in GDM group, significantly lower than that in the control group (42.1%, P < 0.05). There was no significant difference in the frequency of G/G genotype between GDM group and control group (52.9% vs 41.4%, P > 0.05). (3) Women in control group were more likely to be homozygous for the allele A of site rs228648 than women with GDM. The frequency of A/A genotype of rs228648 was negatively correlated with GDM group. By the logistic procedure, after adjustment by age and gestational weeks, the odds ratio was 0.312, and Wald Confidence Limites were 0.108 to 0.900 (P = 0.031). CONCLUSION: Urotensin II gene may contribute to the genetic susceptibility to gestational diabetes mellitus in northern Chinese population. G allele of site rs228648 is related to GDM possibly, and that homozygosis A of site rs228648 is likely to be an important protecting factor for GDM.

Establishment of a Simple and Quick Method for Detecting Extended-Spectrum ß-Lactamase (ESBL) Genes in Bacteria.

Extended-spectrum ß-lactamase (ESBL) genes that render bacteria resistant to antibiotics are commonly detected using phenotype testing, which is time consuming and not sufficiently accurate. To establish a better method, we used phenotype testing to identify ESBL-positive bacterial strains and conducted PCR to screen for TEM (named after the patient Temoneira who provided the first sample), sulfhydryl reagent variable (SHV), cefotaxime (CTX)-M-1, and CTX-M-9, the 4 most common ESBL types and subtypes. We then performed multiplex PCR with 1 primer containing a biotin and hybridized the PCR products with gene-specific probes that were coupled with microbeads and coated with a specific fluorescence. The hybrids were linked to streptavidin-R-phycoerythrins (SA-PEs) and run through a flow cytometer, which sorted the fluorescently dyed microbeads and quantified the PEs. The results from single PCR, multiplex PCR, and cytometry were consistent with each other. We used this method to test 169 clinical specimens that had been determined for phenotypes and found 154 positive for genotypes, including 30 of the 45 samples that were negative for phenotypes. The CTX-M genotype tests alone, counting both positive and negative cases, showed 99.41% (168/169) consistency with the ESBL phenotype test. Thus, we have established a multiplex-PCR system as a simple and quick method that is high throughput and accurate for detecting 4 common ESBL types and subtypes.