Testing the passive sampling hypothesis: The role of dispersal in shaping microbial species-area relationship.

Dispersal is one of the key processes determining biodiversity. The passive sampling hypothesis, which emphasizes dispersal processes, suggests that larger habitats receive more species from the species pool as the main mechanism leading to more species in larger habitats than in smaller habitats (i.e., species-area relationships). However, the specific mechanisms by which dispersion shapes biodiversity still need to be discovered due to the difficulties of quantifying dispersal and the influence of multiple factors. Solving the above problem with a designed experiment is necessary to test the passive sampling hypothesis. This study designed a passive sampling experiment using sterile filter paper to quantify the microbial diffusion process, excluding the effects of pure sampling effects, habitat heterogeneity, and extinction processes. The results of high-throughput sequencing showed that a larger filter paper could receive more colonists, and the passive sampling hypothesis of SAR was confirmed. Dispersal shaped SAR by increasing species richness, especially rare species, and increasing the species replacement rate between habitats. These two processes are the mechanisms by which dispersal shapes biodiversity patterns. Compared with the results of this study, the commonly used mathematical model of passive sampling was able to predict the richness of non-rare species accurately but underestimated the richness of rare species. Underestimating rare species by mathematical models of passive sampling is more severe in small habitats. These findings provide new insights into the study of dispersal processes and the mechanism of species-area relationships.

Testing the Resource Hypothesis of Species-Area Relationships: Extinction Cannot Work Alone.

The mechanisms that underpin the species-area relationship (SAR) are crucial for both the development of biogeographic theory and the application of biodiversity conservation. Since its origin, the resource hypothesis, which proposes that rich resources in vast ecosystems will lower extinction rates and shape the SAR, has not been tested. The impossibility to quantify resources and extinction rates using plants and animals as research subjects, as well as the inability to rule out the influences of the area per se, habitat diversity, dispersal, and the historical background of biodiversity, make testing this hypothesis problematic. To address these challenges and test this hypothesis, two sets of microbial microcosm experimental systems with positive and negative correlated resources and volumes were created in this work. The results of 157 high-throughput sequencing monitoring sessions at 11 time points over 30 consecutive days showed that neither of the experimental groups with positive or negative correlations between total resources and microcosm volume had a significant SAR, and there were no negative correlations between extinction rates and resources. Therefore, in our microcosmic system, resources do not influence extinction rates or shape the SAR. Dispersal should be the principal mode of action if the resource theory is correct.

[A multi-center randomized controlled trial of intrauterine device use in Chinese women].

OBJECTIVE: To assess the safety and effectiveness of intrauterine device in Chinese women. METHODS: In this multicenter randomized controlled trial, a total of 24 000 women were randomly (1:1:1) into 3 groups of Yuangong Cu 365 (YCu365), Copper T 380A (TCu380A) and Multiload Cu 375 (MLCu375). Clinical outcomes were assessed at 12 months post-insertion, including discontinuation due to pregnancy, expulsion, hemorrhage and downward displacement, etc. The overall and causal-specific discontinuation rates for adverse events were calculated. RESULTS: At the end of the first year, the discontinuation rate of YCu365 (4.21%) was the lowest, followed by TCu380A (8.42%) and MLCu375 (13.91%) (P < 0.01). The differences of discontinuation rates for pregnancy, expulsion, hemorrhage and downward displacement between these IUDs were also significant. MLCu375, side effect without medical treatment, fewer follow-ups, deeper uterine cavity and previous IUD failure were significantly associated with an increased risk of IUD discontinuation. CONCLUSION: The newly developed indomethacin-releasing YCu365 IUD appears to perform the best. However, its long-term safety and cost-effectiveness should be further evaluated.

Fe(x)O(y)@C spheres as an excellent catalyst for Fischer-Tropsch synthesis.

We demonstrate a one-pot hydrothermal cohydrolysis-carbonization process using glucose and iron nitrate as starting materials for the fabrication of carbonaceous spheres embedded with iron oxide nanoparticles. It is verified by TEM, (57)Fe Mossbauer, and Fe K-edge XAS that iron oxide nanoparticles are highly dispersed in the carbonaceous spheres, leading to a unique microstructure. A formation mechanism is also proposed. This route is also applicable to a range of other naturally occurring saccharides and metal nitrates. A catalytic study revealed the remarkable stability and selectivity of the reduced Fe(x)O(y)@C spheres in the Fischer-Tropsch synthesis, which clearly exemplifies the promising application of such materials.

Mild and selective deprotection method of acetylated steroids and diterpenes by dibutyltin oxide.

Dibutyltin oxide (DBTO) was first utilized for the deacetylation of steroid and diterpene esters. The results showed the deprotection of acetylated steroids and diterpenes separately with moderate catalysis dibutyltin oxide in methanol selectively removed part acetyl groups of these substrates, whereas several functional groups of the steroids and diterpenes were retained and neither isomerization nor degradation of these substrates was observed. It seems that the acetyl groups with lower steric hindrance or near carbonyl, alkoxy, or hydroxyl groups can be cleaved by the reaction, whereas the acetyl groups with higher steric hindrance or without carbonyl, alkoxy, or hydroxyl groups neighboring were retained under the same conditions. One of the interesting results obtained was the selective hydrolysis of the 3beta-O-acetyl group in the presence of the 6beta group in 3beta,6beta-Di-O-acetyl-5alpha-hydroxypregn-16-en-20-one. This allows for subsequent introduction of one unit at C-3 and the other unit at C-6. This procedure is useful for the synthesis of a series of closely related isomers of 3beta,5alpha,6beta-trihydroxypregn-16-en-20-one and other widespread polyhydroxysteroids in marine organisms and some terrestrial species.

[Study on the correlation between induced abortion and reproductive tract infections].

OBJECTIVE: To explore the correlation between induced abortion and reproductive tract infections (RTIs). METHODS: On the basis of keeping the representation of cities under study, 53 652 fertile women aged 15 - 49 were surveyed by using a stratified-cluster-random sampling. Investigation and gynecological examination were conducted by two steps - firstly converging at the clinics, and then visiting those households for someone who did not show up at the clinics. RESULTS: Among all the 32.0% (n=16 800) women ever having experienced the history of induced abortion, 21.1% (n = 11 090) of them had one, 7.6% (n=3976) women had two, and 4.1% (n=1734) women had at least three events. 59.0% (n=30 959) women among our studied samples had ever had RTI, with 30.9% (n=16 215) of them had only one 20.0% (n=10 494) women had two and 8.1% (n=4250) had three or more RTIs. Data from χ(2) text and ordinal regression analysis revealed that the rural married women who underwent more induced abortions were more likely to suffer from RTIs, especially cervical infection and PID. CONCLUSION: Our study showed that the rates of induced abortion and reproductive tract infections among married women in Anhui province were both high. Women who underwent induced abortions had a higher prevalence rate of reproductive tract infections.

[Study on a breast-disease screening program and related factors among rural married women at reproductive age in Anhui province].

OBJECTIVE: To study the prevalence and its related factors on breast-diseases among women at reproductive age in the rural areas of Anhui province, and to provide data for the development of prevention and healthcare on breast-diseases. METHODS: 54 400 rural fertile women aged 15 - 49 were surveyed by a stratified-cluster-random sampling method. Breast examination was conducted in two steps: converging at the clinics, and later visiting their households. Clinical examination and X-ray scanning check up were performed. RESULTS: The rate of the breast-disease among the rural fertile women was 10.69%, and the first three breast-diseases were galactophore hyperplasia, fibroadenoma and intracanalicular papilloma, their prevalence were 9.39%, 0.65% and 0.50% respectively. The results of logistic regression showed in comparison with women and their husbands who were under 29, low education, husbands being farmers, medium menstrual flow, no dysmenorrheal, the total number of deliveries was 0 while no history of abortion, those who aged 30 to 44, high education, husbands were doing other jobs (they were mainly businessmen or teachers), more menstrual flow, dysmenorrheal, the total number of deliveries was 1, they were more likely to got breast diseases. However in comparison with women who earned less than 5000 Yuan per year, those who had 5001 to 8000 Yuan per year were less likely to get breast diseases. CONCLUSION: Breast diseases were prevalent among rural fertile women and were affected by multi-factors. We suggested that screening program on breast cancer should be carried out at regular intervals and at the same time, to intensify second-class prevention of breast cancer, together with actively treating patients with galactophore hyperplasia, to reduce the prevalence of precancerous pathological changes.

Risk factors for reproductive tract infections among married women in rural areas of Anhui Province, China.

OBJECTIVES: The goal of this study is to identify factors that contribute to reproductive tract infections (RTIs) among women in rural China, including prevalence, influence of sociodemographic characteristics, knowledge, hygienic behaviors and the history of childbearing, menstruation and abortion. STUDY DESIGN: A stratified cluster sample of 53,652 married women in rural Anhui Province of China completed an interviewer-administered standardized questionnaire, and underwent gynecological examination and laboratory investigation. RESULTS: RTIs were relatively common (30,939/58.1%) among our sample of 53,652 married women. The three most frequent RTIs in our samples were endocervicitis, bacterial vaginosis (BV) and trichomoniasis, with prevalences of 41.7%, 12.0% and 4.5%, respectively. Multiple infections were prevalent among our sample. 20.4% (10,854) of our sample had two RTIs and 8.8% (4713) had at least three RTIs. Multivariate analysis showed that women's age, education, occupation, dysmenorrhea, number of deliveries, personal hygiene habit, menstrual cycle, menstruation, abortion, the interval between abortion and sexual intercourse afterwards, RTI knowledge and the frequency of sexual intercourse per month were all related to RTIs in our sample. CONCLUSIONS: Among married women in rural China, the prevalence of RTIs was high, indicating the need for health education.

[Health seeking behavior and related influential factors on rural reproductive tract infections among rural women at reproductive age].

OBJECTIVE: To understand health seeking behavior and its influential factors to reproductive tract infections (RTIs) on women at reproductive age in the rural areas. METHODS: 54540 fertile women aged 15 - 49 were surveyed by a stratified-cluster-random sampling method and gynecological examination were conducted in two steps: converging at the clinics, and then visiting their households, later, 31 624 women who had at least one RTI symptom were chosen. RESULTS: Among all the women at reproductive age, the rate of having at least one RTI symptom was 59.8% with the means of RTI symptom as 1.66 +/- 0.89. 15989 women went to see doctors out of the 31 624 women who had RTI symptoms, with a proportion of 50.6%. The results of logistic regress showed that those women whose husbands having higher education level, higher income, more RTI symptoms and better knowledge on RTI were more easily to go to the hospitals. However, those women whose husbands working out of the county, having older first bearing age and more numbers of pregnancy were less likely to go to the hospitals. Reasons that refrained them from going to see a doctor would include: 2137 (13.7%) did not know that RTI was a disease; 7443 (47.6%) of them thought that every woman were bound to have at least one symptom and it did not matter; 1629 (10.4%) of them felt shameful; 349 (2.2%) learned that the diseases were incurable; 975 (6.2%) felt the cost of treatment was too expensive; 2101 (13.4%) had no time; 1001 (6.4%) would treat themselves through buying medicines over the counter. CONCLUSION: RTI symptoms were quite prevalent among women at reproductive age but the rate of seeing a doctor was low and caused by multi-factors. Health education and gynecological census in increasing the curable rate of RTIs should to be strengthened.