Artificial intelligence-aided diagnostic imaging: A state-of-the-art technique in precancerous screening.

BACKGROUND AND AIM: Chromoendoscopy with the use of indigo carmine (IC) dye is a crucial endoscopic technique to identify gastrointestinal neoplasms. However, its performance is limited by the endoscopist's skill, and no standards are available for lesion identification. Thus, we developed an artificial intelligence (AI) model to replace chromoendoscopy. METHODS: This pilot study assessed the feasibility of our novel AI model in the conversion of white-light images (WLI) into virtual IC-dyed images based on a generative adversarial network. The predictions of our AI model were evaluated against the assessments of five endoscopic experts who were blinded to the purpose of this study with a staining quality rating from 1 (unacceptable) to 4 (excellent). RESULTS: The AI model successfully transformed the WLI of polyps with different morphologies and different types of lesions in the gastrointestinal tract into virtual IC-dyed images. The quality ratings of the real IC-dyed and AI images did not significantly differ concerning surface structure (AI vs IC: 3.08 vs 3.00), lesion border (3.04 vs 2.98), and overall contrast (3.14 vs 3.02) from 10 sets of images (10 AI images and 10 real IC-dyed images). Although the score depended significantly on the evaluator, the staining methods (AI or real IC) and evaluators had no significant interaction (P > 0.05) with each other. CONCLUSION: Our results demonstrated the feasibility of employing AI model's virtual IC staining, increasing the possibility of being employed in daily practice. This novel technology may facilitate gastrointestinal lesion identification in the future.

Functional Characterization and Protein Engineering of a Triterpene 3-/6-/2'-O-Glycosyltransferase Reveal a Conserved Residue Critical for the Regiospecificity.

Engineering the function of triterpene glucosyltransferases (GTs) is challenging due to the large size of the sugar acceptors. In this work, we identified a multifunctional glycosyltransferase AmGT8 catalyzing triterpene 3-/6-/2'-O-glycosylation from the medicinal plant Astragalus membranaceus. To engineer its regiospecificity, a small mutant library was built based on semi-rational design. Variants A394F, A394D, and T131V were found to catalyze specific 6-O, 3-O, and 2'-O glycosylation, respectively. The origin of regioselectivity of AmGT8 and its A394F variant was studied by molecular dynamics and hydrogen deuterium exchange mass spectrometry. Residue 394 is highly conserved as A/G and is critical for the regiospecificity of the C- and O-GTs TcCGT1 and GuGT10/14. Finally, astragalosides III and IV were synthesized by mutants A394F, T131V and P192E. This work reports biocatalysts for saponin synthesis and gives new insights into protein engineering of regioselectivity in plant GTs.

Functional Characterization and Structural Basis of an Efficient Di-C-glycosyltransferase from Glycyrrhiza glabra.

A highly efficient di-C-glycosyltransferase GgCGT was discovered from the medicinal plant Glycyrrhiza glabra. GgCGT catalyzes a two-step di-C-glycosylation of flopropione-containing substrates with conversion rates of >98%. To elucidate the catalytic mechanisms of GgCGT, we solved its crystal structures in complex with UDP-Glc, UDP-Gal, UDP/phloretin, and UDP/nothofagin, respectively. Structural analysis revealed that the sugar donor selectivity was controlled by the hydrogen-bond interactions of sugar hydroxyl groups with D390 and other key residues. The di-C-glycosylation capability of GgCGT was attributed to a spacious substrate-binding tunnel, and the G389K mutation could switch di- to mono-C-glycosylation. GgCGT is the first di-C-glycosyltransferase with a crystal structure, and the first C-glycosyltransferase with a complex structure containing a sugar acceptor. This work could benefit the development of efficient biocatalysts to synthesize C-glycosides with medicinal potential.

[Establishment of a model of reproductive system injury in male Wistar rats in high-altitude hypoxia environment].

OBJECTIVE: To establish a model of reproductive system injury in male rats at high altitude using the low-pressure hypoxic animal laboratory and study the changes in the testicular tissue, semen parameters, blood gas and oxidative stress in male rats at different altitudes. METHODS: Sixty male Wistar rats were randomly assigned to be raised on the plains (the plains group, n = 20), at an altitude of 4 000 m (the plateau model group Ⅰ, n = 20), or at an altitude of 6 000 m (the plateau model group Ⅱ, n = 20) for a spermatogenic cycle of 14 days. After establishment of the model of high-altitude reproductive system injury, the testis tissues of the rats were harvested for HE staining and observed for histopathological changes under the light microscope, and their epididymedes collected for preparation of sperm suspension and detection of sperm motility, sperm count and the percentage of morphologically abnormal sperm (MAS). The blood gas level and oxidative stress-related indexes in different groups were also measured using the serological test. RESULTS: With the elevation of altitude, the levels of pH and PO2 were decreased, those of PCO2, Hct, K+, Cl－ and Hb increased markedly, while that of Na+ exhibited no significant change. The model rats also showed folded spermatogenic tubule walls, thinned spermatogenic epithelia, disorderly arranged and reduced number of spermatogenic cells, and increased vascuolization in the spermatogenic epithelia, with decreased sperm motility and count, increased percentage of MAS, elevated concentration of malondialdehyde (MDA) and reduced activity of superoxide dismutase (SOD). CONCLUSIONS: A model of reproductive system injury was successfully established in male rats at a simulated altitude of 4 000 m. With increasing of the altitude to 6000 m, oxidative damage to the testicular tissue was aggravated, sperm motility decreased, and the percentage of MAS increased, indicating that an altitude of 6 000 m may cause serious damage to the rat reproductive system.

[Clinical treatment of erectile dysfunction in type 2 diabeticpatients in the high-altitude area].

OBJECTIVE: To investigate the safety and efficacy of pancreatic kininogenase combined with sildenafil in the treatment of erectile dysfunction(ED) in type 2 diabetes mellitus (DM) patients in the high-altitude area. METHODS: This study included 93 ED patients with type 2 DM, all residents of the Xining area 1500 meters above sea level. We randomly divided them into an experimental group (n = 48) and a control group (n = 45), the former treated with pancreatic kininogenase(120 u, tid) and sildenafil (25 mg, qd at bedtime), while the latter with sildenafil only (25 mg, qd at bedtime).After 4 and 8 weeks of medication, we obtained the penile hemodynamic parameters,IIEF-5 scores, and sexual intercourse satisfaction(SIS) scores and compared them between the two groups of patients. RESULTS: There were no statistically significant differences in age or DM course between the two groups of patients (P >0.05).Compared with the baseline, both the experimental and control groups showed remarkably improvement inthe IIEF-5 score (8.81 ± 2.06 vs 11.54 ± 7.72 and 8.29 ± 1.91 vs 9.37± 1.65, P <0.05), SIS score (3.35 ± 2.43vs6.83± 2.61and 3.41 ± 2.38 vs 4.92± 2.49, P <0.05), and penile hemodynamic parameters obtained by color duplex Doppler ultrasonography(P <0.05), with significant differences between the two groups in the IIEF-5 score (11.54 ± 7.72 vs 9.37± 1.65, P <0.05) and SIS score (6.83± 2.61 vs 4.92± 2.49, P <0.05) but not in the penile hemodynamic parameters (P >0.05). Even more remarkable improvement was observed at 8 weeks in the experimental and control groups in the IIEF-5 score (19.29± 1.85 and 15.43± 1.74)(P <0.05), SIS score (11.73 ± 2.57 and 6.55± 2.71) (P <0.05), and penile hemodynamic parameters(P <0.05), all with significant differences between the two groups (P <0.05). CONCLUSIONS: Pancreatic kininogenase combined with sildenafil has a better clinical effect than sildenafil alone on ED in type 2 DM patientsin the high-altitude area.

Human infection and environmental contamination with Avian Influenza A (H7N9) Virus in Zhejiang Province, China: risk trend across the three waves of infection.

BACKGROUND: The third wave of H7N9 cases in China emerged in the second half of 2014. This study was conducted to identify the risk trends of H7N9 virus in human infections and environment contamination. METHODS: A surveillance program for H7N9 virus has been conducted in all 90 counties in Zhejiang since March 2013. All H7N9 cases were reported by hospitals through the China Information System for Disease Control and Prevention. Sampling sites for environment specimens were randomly selected by a multi-stage sampling strategy. Poultry-related workers for serological surveillance were randomly selected from the sampling sites for environmental specimens in the first quarter of each year. rRT-PCR and viral isolation were performed to identify H7N9 virus. A hemagglutination inhibition assay was conducted to detect possible H7N9 infection among poultry-related workers. RESULTS: A total of 170 H7N9 cases were identified in Zhejiang from 20 March 2013 to 28 February 2015. The proportion of rural cases increased from 42.2% (19/45) to 67.7% (21/31) with progression of the three epidemics (P < 0.05). In 32% (161/503) of towns and 16.0% (238/1488) of surveyed premises, H7N9 virus was detected in the environment. The positive rate of environmental specimens was 6.1% (868/14207). In addition, 912 poultry-related workers were recruited and 3.7% (34) of them tested positive for H7N9 antibodies. Positive detection of H7N9 virus during environmental surveillance increased from the first to third wave (P < 0.05). Almost all positive rates of environmental surveillance were higher in urban than rural in the second wave (P < 0.05), however they were higher in rural area in the third wave (P < 0.05). CONCLUSIONS: Our study highlights that the severity of poultry-related environmental contamination by H7N9 virus is intensifying. We strongly recommend that the local government stop illegal trading immediately and close live poultry markets in the territory. Poultry operations in slaughtering plants must be supervised rigorously. Prior to the closure of live poultry markets, daily cleaning and disinfecting of areas potentially contaminated by H7N9 virus, centralized collection and disposal of trash, designating certain days as market rest days, banning overnight poultry storage and other measures should be strictly carried out in both urban and rural areas.

[Construction of early warning model of influenza-like illness in Zhejiang Province based on support vector machine].

OBJECTIVE: To construct a forecasting model of influenza-like illness in Zhejiang Province. METHODS: The number of influenza-like cases and related pathogens among outpatients and emergency patients were obtained from 11 sentinel hospitals in Zhejiang Province during 2012 to 2013 (total 104 weeks), and corresponding meteorological factors were also collected. The epidemiological characteristics of influenza during the period were then analyzed. Linear correlation and rank correlation analyses were conducted to explore the association between influenza-like illness and related factors. Optimal parameters were selected by cross validation. Support vector machine was used to construct the forecasting model of influenza-like illness in Zhejiang Province and verified by the historical data. RESULTS: Correlation analysis indicated that 8 factors were associated with influenza-like illness occurred in one week. The results of cross validation showed that the optimal parameters were C=3, ε=0.009 and γ=0.4. The results of influenza-like illness forecasting model after verification revealed that support vector machine had the accuracy of 50.0% for prediction with the same level, while it reached 96.7% for prediction within the range of one level higher or lower. CONCLUSION: Support vector machine is suitable for early warning of influenza-like illness.

[Semi-quantitative risk assessment on local transmission of Dengue fever caused by introduced cases].

OBJECTIVE: To assess the risk of local transmission of Dengue caused by introduced cases with semi-quantitative method in 2015 in Zhejiang Province. METHODS: Risk indexes of local transmission of Dengue caused by introduced cases were reviewed. The weights of indexes were computed by analytic hierarchy process and further used to generate absolute risk values by multiplying indexes. Moreover, comprehensive indexes were computed to describe relative risk by combining analytic hierarchy process and TOPSIS methods. RESULTS: Four primary indexes and 19 secondary indexes were identified for risk assessment of local transmission of Dengue. The indexes with maximum and minimum weight were the number of immigration from countries with Dengue patients (weight value: 0.0678) and density of population (weight value: 0.0371) respectively. All CR values, statistics for measuring consistency of score matrix, were less than 0.1 (minimum: 0.000, maximum: 0.0922, average: 0.0251). The absolute risk of Zhejiang Province was within the range of 0.397-0.504 (the full score was 1.0). The risk orders of 11 municipalities sorted by relative comprehensive indexes and absolute risk values methods were similar. The three highest municipalities were Hangzhou, Wenzhou and Ningbo and the ranges of absolute risk value were 0.387-0.494, 0.404-0.511 and 0.392-0.499 respectively. CONCLUSION: The results provides scientific basis for preventing and controlling Dengue in Zhejiang Province. The indexes and weights may be used to assess risk of Dengue in future. In addition, the semi-quantitative method constructed in this study would be a significant reference for risk assessment of public health in emergencies.

Functional characterization, structural basis, and regio-selectivity control of a promiscuous flavonoid 7,4'-di-O-glycosyltransferase from Ziziphus jujuba var. spinosa.

A highly efficient and promiscuous 7,4'-di-O-glycosyltransferase ZjOGT3 was discovered from the medicinal plant Ziziphus jujuba var. spinosa. ZjOGT3 could sequentially catalyse 4'- and 7-O-glycosylation of flavones to produce 7,4'-di-O-glycosides with obvious regio-selectivity. For 7,4'-dihydroxyl flavanones and 3-O-glycosylated 7,4'-dihydroxyl flavones, ZjOGT3 selectively catalyses 7-O-glycosylation. The crystal structure of ZjOGT3 was solved. Structural analysis, DFT calculations, MD simulations, and site-directed mutagenesis reveal that the regio-selectivity is mainly controlled by the enzyme microenvironment for 7,4'-dihydroxyl flavones and 3-O-glycosylated 7,4'-dihydroxyl flavones. For 7,4'-dihydroxyl flavanones, the selectivity is mainly controlled by intrinsic reactivity. ZjOGT3 is the first plant flavonoid 7,4'-di-O-glycosyltransferase with a crystal structure. This work could help understand the catalytic mechanisms of multi-site glycosyltransferases and provides an efficient approach to synthesise O-glycosides with medicinal potential.

Insights into the missing apiosylation step in flavonoid apiosides biosynthesis of Leguminosae plants.

Apiose is a natural pentose containing an unusual branched-chain structure. Apiosides are bioactive natural products widely present in the plant kingdom. However, little is known on the key apiosylation reaction in the biosynthetic pathways of apiosides. In this work, we discover an apiosyltransferase GuApiGT from Glycyrrhiza uralensis. GuApiGT could efficiently catalyze 2″-O-apiosylation of flavonoid glycosides, and exhibits strict selectivity towards UDP-apiose. We further solve the crystal structure of GuApiGT, determine a key sugar-binding motif (RLGSDH) through structural analysis and theoretical calculations, and obtain mutants with altered sugar selectivity through protein engineering. Moreover, we discover 121 candidate apiosyltransferase genes from Leguminosae plants, and identify the functions of 4 enzymes. Finally, we introduce GuApiGT and its upstream genes into Nicotiana benthamiana, and complete de novo biosynthesis of a series of flavonoid apiosides. This work reports an efficient phenolic apiosyltransferase, and reveals mechanisms for its sugar donor selectivity.

[Meta-analysis on efficacy and safety of Shenmai injection in treatment of coronary heart disease].

OBJECTIVE: To evaluate the efficacy and safety of Shenmai injection in the treatment of coronary heart disease (CHD). METHOD: CNKI (1979 to December 2011), VIP (1989 to December 2011), and Wanfang Data (1987 to December 2011) were retrieved for literatures concerning randomized controlled trials of Shenmai injection in the treatment of coronary heart disease. Their quality was assessed by the Jadad scale. Review Manager 5.0 and Stata 12 software were adopted for data analysis. RESULT: Altogether 18 randomized clinical trials were included in the Meta-analysis. According to the findings, compared with routine therapy alone, the combination of Shenmai injection and routine therapy increased the overall effective rate by clinical symptoms by 22% [RD = 0.22, 95% CI (0.17, 0.26), P<0.000 01], with the relative risk ratio of [RR = 1.31, 95% CI (1.20, 1.43), P<0.000 1] and the efficacy by electrocardiogram by 25% [RD = 0.25, 95% CI (0.19, 0.31), P<0.000 01], with the relative risk ratio of [RR = 1.46, 95% CI (1.32, 1.62), P<0.000 1]. It also improved New York heart association classification (NYHA) by 33% [RD = 0.33, 95% CI (0.16, 0.49), P<0.000 01], with the relative risk ratio of [RR = 1.79, 95% CI (1.28, 2.51), P = 0.000 6] and left ventricular ejection fraction [WMD 7.55, 95% CI (2.28, 12.83)]. Additionally, studies reported that Shenmai injection could increase left ventricular stroke volume, decrease left ventricular end systolic diameter, improved hemodynamic indexes, reduced NT-pro-BNP, DMA, cytokines, TNF-alpha, IL-6 and serum enzyme, mitigated infarction-related revascularization IRA indexes and shortened the symptom improvement time and electrocardiogram recovery time. Three studies had reported adverse events, mainly dizziness, palpitation, mild abdominal distension, nausea, metal excitement and flushed face, with no serious adverse effect. CONCLUSION: Clinical evidences prove that Shenmai injection has certain effect in treating CHD and remains to be improved in the overall effective rate. The essay, despite of some shortcomings, provides certain reference for clinical application. It is suggested holding more multicenter randomized controlled trials with rational design, strict implementation, large sample size and sufficient following-up time to further verify its efficacy and safety.

The clinical value of three-dimensional measurement in the diagnosis of thoracic myelopathy caused by ossification of the ligamentum flavum.

BACKGROUND: Thoracic ossification of the ligamentum flavum (OLF) is a major cause of thoracic myelopathy, which is often accompanied by multiple segmental stenosis or other degenerative spinal diseases. However, in the above situations, it is difficult to determine the exact segment responsible. The objective of this study was to analyze three-dimensional (3D) radiological parameters in order to establish a novel diagnostic method for discriminating the responsible segment in OLF-induced thoracic myelopathy, and to evaluate its superiority compared to the conventional diagnostic methods. METHODS: Eighty-one patients who underwent surgery for thoracic myelopathy caused by OLF from 2016 to 2020 were enrolled in this study as the myelopathy group, and 79 patients who had thoracic OLF but displayed no definite neurological signs from 2018 to 2020 were enrolled as the non-myelopathy group. We measured the one-dimensional (1D), two-dimensional (2D), and 3D radiological parameters, calculated their optimal cutoff values, and compared their diagnostic values. RESULTS: Significant differences were observed in the 1D, 2D, and 3D radiological parameters between the myelopathy and non-myelopathy groups (P<0.01). As a 3D radiological parameter, the OLF volume (OLFV) ratio (OLFV ratio = OLFV/normal canal volume × 100%) was the most accurate parameter for diagnosing OLF-induced thoracic myelopathy, with a diagnostic coincidence rate of 88.1%. We also found that an OLFV ratio of 26.3% could be used as the optimal cutoff value, with a sensitivity of 87.7% and a specificity of 88.6%. Moreover, the OLFV ratio [area under the curve (AUC): 0.92, 95% confidence interval (CI): 0.86-0.95] showed a statistically higher diagnostic value than the 1D and 2D parameters (AUC: 0.75, 95% CI: 0.67-0.81; AUC: 0.84, 95% CI: 0.77-0.89, respectively) (P<0.05). Pearson correlation analysis illustrated that the OLFV ratio was significantly negatively correlated with preoperative modified Japanese Orthopedic Association (mJOA) score (r=-0.73, 95% CI: -0.81 to -0.60, P<0.01). CONCLUSIONS: Our results demonstrate the superiority of the OLFV ratio over the conventional 1D and 2D computed tomography (CT)-based radiological parameters for the diagnosis of OLF-induced thoracic myelopathy. The novel diagnostic method based on the OLFV ratio will help to determine the responsible segment in multi-segmental thoracic OLF or when thoracic OLF coexists with other degenerative spinal diseases. The OLFV ratio also accurately reflects the clinical state of symptomatic patients with thoracic OLF.

A U-shaped Association of Breastfeeding Duration with Cognitive Impairment in Chinese Postmenopausal Women.

Breastfeeding is related to maternal health. However, the association of women's breastfeeding duration with cognitive function in their later life is limited and inconsistent. The aim of this study was to accurately evaluate the association in Chinese postmenopausal women. We analyzed the data from Zhejiang Ageing and Health Cohort Study including 5487 postmenopausal women. Cognitive impairment was assessed via the Mini-Mental State Examination. Data on breastfeeding duration was collected in the reproductive history section within the questionnaire. Generalized additive models (GAMs) and logistic regression models, controlled for an extensive range of potential confounders, were generated to examine the associations. A U-shaped association was identified between breastfeeding duration and cognitive impairment based on GAM. The nadir with lowest odds of cognitive impairment was ascertained by quadratic model as 12 months. The logistic models showed that compared with women breastfeeding 12 months per child, the fully adjusted odds ratios (ORs) were 1.50 (95% Confidence Interval (CI): 1.20-1.88), 1.58 (95% CI: 1.29-1.93), 1.33 (95% CI: 1.06-1.68), 2.08 (95% CI: 1.64-2.65) for those averagely breastfeeding <6, 6-<12,>12-18,>18 months, respectively. Furthermore, we did not observe significant effect modification of the association. Future longitudinal studies are needed to confirm the association.

Association of postlunch napping duration and night-time sleep duration with cognitive impairment in Chinese elderly: a cross-sectional study.

OBJECTIVE: To analyse the independent and combined associations of postlunch napping duration and night-time sleep duration with risk of cognitive impairment among Chinese elderly. DESIGN: A cross-sectional study. SETTING: We analysed the data from Zhejiang Ageing and Health Cohort, a population-based survey of seven counties located in Zhejiang province in eastern China. PARTICIPANTS: 10 740 participants aged 60 years or older were included in final analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: Cognitive impairment was assessed through Mini-Mental State Examination. Data on sleep-related characteristics was collected in the behavioural habits section within the questionnaire. RESULTS: Relative to participants with 1-30 min of postlunch napping, those who did not nap and who napped longer had significantly higher risks for cognitive impairment. OR of cognitive impairment were 1.41 (95% CI 1.14 to 1.75) for participants with longer night-time sleep duration (≥9 hours), compared with those sleeping 7-8.9 hours. In addition, combined effects were further identified. Participants with both longer night-time sleep duration (≥9 hours) and longer postlunch napping duration (>60 min) (OR=2.01, 95% CI 1.30 to 3.13), as well as those with both longer night-time sleep duration (≥9 hours) and appropriate postlunch napping duration (1-30 min) (OR=2.01, 95% CI 1.20 to 3.38), showed significantly higher risk of cognitive impairment than those with sleeping 7-8 hours and napping 1-30 min. Meanwhile, a 34% increase in odds of cognitive impairment was observed in participants with both shorter night-time sleep duration (5-6.9 hours) and no napping. CONCLUSION: Both postlunch napping duration and night-time sleep duration were independently and jointly associated with cognitive impairment, which needs verification in prospective studies.

Tea consumption is inversely associated with depressive symptoms in the elderly: A cross-sectional study in eastern China.

BACKGROUND: Epidemiological studies suggest that higher tea consumption was associated with lower risk of depressive symptoms, but this has not been found consistently. Moreover, the effect of different types of tea on depressive symptoms needs to be further explored. This study aimed to examine the association between tea consumption and depressive symptoms in Chinese elderly. METHODS: We analyzed the baseline data from Zhejiang Major Public Health Surveillance Program including 9371 participants. Depressive symptoms was assessed through the application of Patient Health Questionnaire-9 scale (PHQ-9). Logistic regression models, controlled for an extensive range of potential confounders, were generated to evaluate the association between tea consumption and risk of depressive symptoms. RESULTS: The black tea drinkers had a significantly decreased risk of depressive symptoms (p<0.01), whereas no association was found in green tea drinkers. Compared with non-drinkers, the adjusted ORs (95% CIs) were 0.48 (0.23, 0.99) and 0.35 (0.17, 0.72) for participants consuming <3 cups and ≥3 cups of black tea per day, respectively (P for trend: <0.01). A linear association between concentration of black tea and depressive symptoms was also confirmed in our study. LIMITATIONS: Cross-sectional data could not make a causation conclusion, and the observed association in our study could not be ascribed to any specific component in tea. CONCLUSIONS: Our results indicated that higher black tea consumption was associated with a lower prevalence of depressive symptoms in the elderly.

Reproductive history and risk of cognitive impairment in elderly women: a cross-sectional study in eastern China.

BACKGROUND: Epidemiological studies suggest that proxies of higher lifetime estrogen exposure are associated with better cognitive function in postmenopausal women, but this has not been found consistently. OBJECTIVE: To determine whether reproductive history, an important modifier of estrogen exposure across the lifetime, is associated with risk of cognitive impairment in postmenopausal women. METHODS: We analyzed the baseline data from Zhejiang Major Public Health Surveillance Program (ZPHS) including 4,796 postmenopausal women. Cognitive impairment was assessed through the application of Mini-Mental State Examination questionnaire. Logistic regression models, controlled for an extensive range of potential confounders, were generated to examine the associations between women's reproductive history and risk of cognitive impairment in their later life. RESULTS: The length of reproductive period was inversely associated with risk of cognitive impairment (p = 0.001). Odds ratio (OR) of cognitive impairment were 1.316 (95% CI 1.095∼1.582) for women with 5 or more times of full-term pregnancies, compared with those with 1∼4 times of full-term pregnancies. Women without incomplete pregnancy had a significant higher risk of cognitive impairment (OR = 1.194, 95% CI 1.000∼1.429), compared with the reference (1∼2 times of incomplete pregnancies). Oral contraceptive use (OR = 0.489, 95% CI 0.263∼0.910) and intrauterine device (IUD) use (OR = 0.684, 95% CI 0.575∼0.815) were associated with significantly reduced risk of cognitive impairment. CONCLUSION: Our results indicated that shorter reproductive period, higher number of full-term pregnancies and no incomplete pregnancy history were associated with an increased risk of cognitive impairment. In contrast, oral contraceptive and IUD use corresponded to reduced risk of cognitive impairment.

Optimal control in microgrid using multi-agent reinforcement learning.

This paper presents an improved reinforcement learning method to minimize electricity costs on the premise of satisfying the power balance and generation limit of units in a microgrid with grid-connected mode. Firstly, the microgrid control requirements are analyzed and the objective function of optimal control for microgrid is proposed. Then, a state variable "Average Electricity Price Trend" which is used to express the most possible transitions of the system is developed so as to reduce the complexity and randomicity of the microgrid, and a multi-agent architecture including agents, state variables, action variables and reward function is formulated. Furthermore, dynamic hierarchical reinforcement learning, based on change rate of key state variable, is established to carry out optimal policy exploration. The analysis shows that the proposed method is beneficial to handle the problem of "curse of dimensionality" and speed up learning in the unknown large-scale world. Finally, the simulation results under JADE (Java Agent Development Framework) demonstrate the validity of the presented method in optimal control for a microgrid with grid-connected mode.