Chlamydia infection, PID, and infertility: further evidence from a case-control study in China.

BACKGROUND: Chlamydia trachomatis infection and pelvic inflammatory disease (PID) are well-known risk factors for female infertility. But there is limited evidence from China. This study aimed to further explore the associations between previous/current chlamydial infection, PID, and infertility in China. METHODS: We performed a 1:2 matched case-control study with two control groups: pregnant controls and non-pregnant controls in China in 2019. Women diagnosed with infertility were selected as cases (n = 255). Controls were selected based on the following criteria: Pregnant women who were documented in the selected hospitals were chosen as Pregnant controls (n = 510), and people who sought health care in Obstetric/Gynecologic clinics, Family Planning clinics, Dermatology and STD Department or Urological department were selected as Non-pregnant controls (n = 510). Infertility induced by male factors and people who used antibiotics in the vagina within two weeks were excluded. The first-stream specimen of urine samples was tested for chlamydia by nucleic acid amplification testing (NAAT). Conditional logistic regression was used to estimate the association. RESULTS: The prevalence of previous chlamydial infection and PID were significantly higher in cases (2.4%, 17.3%) than in controls (Non-pregnancy: 0.4%, 3.0%; Pregnancy: 0.4%, 9.0%). The current chlamydial infection rates were 5.9%, 7.3%, and 7.1% in infertile, pregnant, and non-pregnant women, respectively. After adjusting for confounders, PID largely elevated the risk of infertility (using non-pregnant controls: adjusted OR = 2.57, 95% CI 1.51, 4.39; using pregnant controls: adjusted OR = 6.83, 95% CI 3.47, 13.43). And the positive association between PID and tubal infertility was more obvious for both groups. For current chlamydial infection, none of the odds ratios were significant at the 0.05 level, while small sample size limited the evaluation of an association between prior chlamydial infection with infertility. CONCLUSIONS: Previous PID was indicated to largely increase the risk of infertility, especially tubal infertility. And there should be continuing emphasis on highly sensitive and specific biomarker for prior chlamydial infection.

Improving Radar Rainfall Estimations with Scaled Raindrop Size Spectra in Mei-Yu Frontal Rainstorms.

Hydrological calibration of raw weather radar rainfall estimation relies on in situ rainfall measurements. Raindrop size distribution (DSD) was collected during three typical Mei-Yu rainstorms in July 2014 using three particle size velocity (Parsivel) DSD sensors along the Mei-Yu front in Nanjing, Chuzhou, and the western Pacific, respectively. To improve the radar precipitation estimation in different parts of the Mei-Yu front, a scaling method was adopted to formulate the DSD model and further derive the Z-R relations. The results suggest a distinct variation of DSDs in different parts of the Mei-Yu front. Compared with statistical radar Z-ARb relations obtained by mathematical fitting techniques, the use of a DSD model fitting based on a scaling law formulation theoretically shows a significant improvement in both stratiform (33.9%) and convective (2.8%) rainfall estimations of the Mei-Yu frontal system, which indicates that using a scaling law can better reflect the DSD variations in different parts of the Mei-Yu front. Polarimetric radar has indisputable advantages with multiparameter detection ability. Several dual-polarization radar estimators are also established by DSD sensor data, and the R(ZH, ZDR) estimator is proven to be more accurate than traditional Z-R relations in Mei-Yu frontal rainfall, with potential applications for operational C-band polarimetric radar.

Isotope 87Rb Faraday filter with a single transmission peak resonant with atomic transition at 780 nm.

We demonstrate an isotope 87Rb Faraday anomalous dispersion optical filter (FADOF) with a single transmission peak resonant with the 5S1/2, F = 2 → 5P3/2, F' = 1, 2, 3 transitions at 780 nm with an enriched 87Rb isotope at low temperature. The isotope 87Rb FADOF achieves a single peak transmission of 74.8% with a bandwidth of 0.96 GHz. Compared with most of FADOFs operated at frequencies far from absorption, the isotope 87Rb FADOF that we have achieved can provide a transmission band exactly covering atomic transitions for many practical applications.

Effects of potential recirculation on air quality in coastal cities in the Yangtze River Delta.

Air quality is closely related to the synoptic circulation and local wind field affecting a certain area as they have distinct influence on the path and speed of pollutants. The Yangtze River Delta is located on the eastern coast, and the air returning from coastal areas has a detrimental effect on air quality in the area. This study proposes to analyze if certain circulation types and the occurrence of recirculation are predominantly related to the occurrence of bad air quality in the Yangtze River Delta. Using sea level pressure data from 2006 to 2016, we used T-mode objective classification to classify circulation in the Yangtze River Delta into nine categories. At the same time, using the Allwine and Whiteman (AW) method, we categorized local winds in the region as ventilation, stagnation, and recirculation types, and we found that the local wind tends to be under recirculation conditions when the region was controlled by circulation types 3 (CT3, southeast low pressure), CT4 (northeast low pressure), CT7 (northwest high pressure), and CT8 (north high pressure, south low pressure, with a large pressure gradient). By comparing concentrations of pollutants and different local wind types, we found that recirculation tended to promote high pollution situations. Use of the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model to simulate the diffusion of pollutants by recirculation in Shanghai in March 2016 confirmed this conclusion. The outputs of HYSPLIT model can show the track of air mass intuitively, and then reflect the effect of recirculation.

Expression for the granular elastic energy.

Granular solid hydrodynamics (GSH) is a broad-ranged continual mechanical description of granular media capable of accounting for static stress distributions, yield phenomena, propagation and damping of elastic waves, the critical state, shear band, and fast dense flow. An important input of GSH is an expression for the elastic energy needed to deform the grains. The original expression, though useful and simple, has some drawbacks. Therefore a slightly more complicated expression is proposed here that eliminates three of them: (1) The maximal angle at which an inclined layer of grains remains stable is increased from 26^{∘} to the more realistic value of 30^{∘}. (2) Depending on direction and polarization, transverse elastic waves are known to propagate at slightly different velocities. The old expression neglects these differences, the new one successfully reproduces them. (3) Most importantly, the old expression contains only the Drucker-Prager yield surface. The new one contains in addition those named after Coulomb, Lade-Duncan, and Matsuoka-Nakai-realizing each, and interpolating between them, by shifting a single scalar parameter.