Studying an off-axis optical bench for future gravity missions from the perspective of carrier-to-noise ratio.

The inter-satellite laser ranging heterodyne interferometer is vital for future gravity missions to achieve high ranging accuracy. This paper proposes a novel off-axis optical bench design which integrates merits of the off-axis optical bench design of GRACE Follow-On mission and other on-axis designs. This design makes use of lens systems subtly to restrict the tilt-to-length coupling noise and takes advantage of the DWS feedback loop to maintain the transmitting beam and receiving beam anti-parallel. The critical parameters of the optical components are determined and the carrier-to-noise ratio for a single channel of the photoreceiver is calculated to be more than 100 dB-Hz for the high case. The off-axis optical bench design is a potential candidate for China's future gravity missions.

Automatic Recognition of Ripening Tomatoes by Combining Multi-Feature Fusion with a Bi-Layer Classification Strategy for Harvesting Robots.

Automatic recognition of ripening tomatoes is a main hurdle precluding the replacement of manual labour by robotic harvesting. In this paper, we present a novel automatic algorithm for recognition of ripening tomatoes using an improved method that combines multiple features, feature analysis and selection, a weighted relevance vector machine (RVM) classifier, and a bi-layer classification strategy. The algorithm operates using a two-layer strategy. The first-layer classification strategy aims to identify tomato-containing regions in images using the colour difference information. The second classification strategy is based on a classifier that is trained on multi-medium features. In our proposed algorithm, to simplify the calculation and to improve the recognition efficiency, the processed images are divided into 9 × 9 pixel blocks, and these blocks, rather than single pixels, are considered as the basic units in the classification task. Six colour-related features, namely the Red (R), Green (G), Blue (B), Hue (H), Saturation (S) and Intensity (I) components, respectively, colour components, and five textural features (entropy, energy, correlation, inertial moment and local smoothing) were extracted from pixel blocks. Relevant features and their weights were analysed using the iterative RELIEF (I-RELIEF) algorithm. The image blocks were classified into different categories using a weighted RVM classifier based on the selected relevant features. The final results of tomato recognition were determined by combining the block classification results and the bi-layer classification strategy. The algorithm demonstrated the detection accuracy of 94.90% on 120 images, this suggests that the proposed algorithm is effective and suitable for tomato detection.

Metal- and Base-Free Room-Temperature Amination of Organoboronic Acids with N-Alkyl Hydroxylamines.

We have found that readily available N-alkyl hydroxylamines are effective reagents for the amination of organoboronic acids in the presence of trichloroacetonitrile. This amination reaction proceeds rapidly at room temperature and in the absence of added metal or base, it tolerates a remarkable range of functional groups, and it can be used in the late-stage assembly of two complex units.

Association between bisphenol A exposure and body mass index in Chinese school children: a cross-sectional study.

BACKGROUND: There is increasing evidence suggesting that Bisphenol A (BPA), one of the highest volume chemicals produced worldwide, can interfere with the body's natural weight control mechanisms to promote obesity. However, epidemiological studies for this are limited, especially for children. METHODS: A cross-sectional study was conducted to investigate the association between BPA exposure and body mass index (BMI) in school children. Three primary and three middle schools were randomly selected from 26 primary and 30 middle candidate schools in Changning District of Shanghai City in China. According to the BMI-based criteria by age and sex for screening of overweight or obese children, we randomly chose 20 obese, 10 overweight, and 30 normal weight children aged 8-15 years of age from each selected school. First morning urine was collected and total urine BPA concentrations were determined by ultra-performance liquid chromatography tandem mass spectrometry. Multiple linear regression analysis was conducted to examine the association of urine BPA concentrations and daily intake estimates with BMI. RESULTS: BPA was detected in 84.9% of urine samples with a geometric mean of 0.45 ng/mL. The daily intake estimates ranged from 0.03 µg/day to 1.96 µg/day with a geometric mean of 0.37 µg/day. The average urine BPA concentrations and daily intake estimates were similar for boys and girls, but significantly higher in older children than younger ones, and showed an increasing trend with BMI. Multiple linear regression analyses showed that urine BPA concentrations were significantly associated with increasing BMI values in all subjects after adjustment for age and sex and the results were similar before and after corrected by urine specific gravity. When stratified by age or sex, the associations remained significant in females and in those 8-11 years of age before corrected by specific gravity. Similar results were shown for the association between BMI and daily intake estimates. CONCLUSIONS: There is a possibility that BPA exposure increases BMI in school children. Given the cross-sectional nature of this study, longitudinal studies are warranted to confirm BPA exposure as a contributor to increased BMI in children.

Urinary antibiotic level of school children in Shanghai, East China, 2017-2020.

In recent years, an extensive exposure to antibiotics from various sources has been demonstrated in China by the biomonitoring method, but the temporal trend remains little known. The study aim was to explore the temporal trend of exposure to antibiotics and associated health risk in children. A dynamic child cohort was established in Shanghai, East China between 2017 and 2020. A total of 684 school children aged 7-11 years were included, and 280 in 2017, 279 in 2018, 288 in 2019, and 287 in 2020 participated in annual surveys. Twenty-three typical antibiotics and three metabolites from five categories (four tetracyclines, five qinolones, six macrolides, eight sulfonamides, and three phenicols), bisphenol A (BPA), and monobutyl phthalate (MBP) were determined in urine. Logistic regression analysis with generalized estimating equations was conducted to investigate the associations between various variables and the detection frequency of antibiotics in urine. Seventeen antibiotics and three metabolites were found in 51.9% of all urine samples. Compared to 2017, the detection frequency in urine reduced 31.8% in 2020 for all antibiotics (58.2% vs 39.7%) and reduced 36.8%-55.8% for tetracyclines (11.4% vs 7.0%), qinolones (34.3% vs 21.3%), macrolides (8.6% vs 3.8%), sulfonamides (16.4% vs 8.7%), and phenicols (19.3% vs 12.2%). After accounting for personal characteristics, food consumption, and urinary BPA and MBP, a decreasing temporal trend of detection frequencies was observed from 2017 to 2020 for most antibiotics. Urinary concentration, estimated daily intake, and acceptable daily intake-based health risk of antibiotics showed a temporal trend similar to detection frequency. There was an extensive exposure to antibiotics in children. However, a decreasing temporal trend occurred for the exposure during the period from 2017 to 2020. The trend was likely to be caused by decreased antibiotic use and/or decreased residues in food and/or drinking water.

Association of triclosan and triclocarban in urine with obesity risk in Chinese school children.

BACKGROUND: Laboratory studies have suggested that triclosan and triclocarban can influence energy metabolism by multiple mechanisms and are potential obesogens, but the effect on obesity risk has not been well investigated in human. OBJECTIVE: To examine the associations of triclosan and triclocarban in urine with childhood obesity. METHODS: We investigated 458 school children aged 7-11 years who entered a dynamic cohort of children established in Shanghai in 2019 and 2020. Triclosan and triclocarban were determined in first morning urine by liquid chromatography coupled to mass spectrometry. Body mass index (BMI) and waist circumference (WC) were used to identify general overweight/obesity and central obesity, respectively. Logistic regression and linear models of generalized estimating equations (GEE) were used to investigate the association between urinary triclosan and triclocarban with obesity prevalence. RESULTS: After adjusting for potential confounders, children with detectable triclocarban in urine had a higher proportion of general overweight/obesity (odds ratio (OR): 1.84; 95% confidential interval (95% CI): 1.19, 2.85) or central obesity (OR: 1.71; 95% CI: 1.03, 2.84). Compared to the low tertile, children in the median tertile of triclosan showed a higher proportion of central obesity (OR: 1.78; 95 %CI: 0.98, 3.24) and children in the high tertile of triclocarban had a higher proportion of general overweight/obesity (OR: 2.25; 95 %CI: 1.31, 3.88) and central obesity (OR: 2.08; 95 %CI: 1.12, 3.87). When the tertiles of triclocarban in urine were treated as a continuous variable, a positive exposure-response relationship was found with general overweight/obesity (OR: 1.50; 95 %CI: 1.15, 1.96) and central obesity (OR: 1.44; 95 %CI: 1.06, 1.95). Multiple linear regression showed a positive exposure-response relationship between triclocarban and BMI (ß: 0.45; 95 %CI: 0.11, 0.80) values. CONCLUSION: Exposure to triclosan and triclocarban was associated with increased risk of childhood obesity. Given the cross-sectional design, more studies are needed to interrogate these findings.

Nickel-catalyzed electrochemical carboxylation of unactivated aryl and alkyl halides with CO2.

Electrochemical catalytic reductive cross couplings are powerful and sustainable methods to construct C-C bonds by using electron as the clean reductant. However, activated substrates are used in most cases. Herein, we report a general and practical electro-reductive Ni-catalytic system, realizing the electrocatalytic carboxylation of unactivated aryl chlorides and alkyl bromides with CO2. A variety of unactivated aryl bromides, iodides and sulfonates can also undergo such a reaction smoothly. Notably, we also realize the catalytic electrochemical carboxylation of aryl (pseudo)halides with CO2 avoiding the use of sacrificial electrodes. Moreover, this sustainable and economic strategy with electron as the clean reductant features mild conditions, inexpensive catalyst, safe and cheap electrodes, good functional group tolerance and broad substrate scope. Mechanistic investigations indicate that the reaction might proceed via oxidative addition of aryl halides to Ni(0) complex, the reduction of aryl-Ni(II) adduct to the Ni(I) species and following carboxylation with CO2.

PIG-A gene mutation as a genotoxicity biomaker in polycyclic aromatic hydrocarbon-exposed barbecue workers.

BACKGROUND: The PIG-A gene mutation assay is a valuable tool for measuring in vivo gene mutations in blood cells. The human PIG-A assay, used as a potential genotoxicity biomarker, is minimally invasive, sensitive, and cost-efficient; however, the relationship between carcinogen exposure and PIG-A mutations is not well understood. METHODS: We investigated the genotoxic effect of red blood cells using PIG-A assay and lymphocyte cytokinesis-block micronucleus test in barbecue restaurant workers (N = 70) exposed to polycyclic aromatic hydrocarbons (PAHs) and self-identified healthy control subjects (N = 56). Urinary PAH metabolites were measured to evaluate internal exposure levels. RESULTS: Multivariate Poisson regression showed that the PAH-exposed workers exhibited significantly higher PIG-A mutant frequency (MF) (8.04 ± 6.81 × 10- 6) than did the controls (5.56 ± 5.26 × 10- 6) (RR = 0.707, 95% CI: 0.615-0.812, P < 0.001). These results indicate that PAH exposure is a risk factor for elevated PIG-A MF. The frequencies of micronuclei (MN) and nuclear buds (NBUD) in the PAH-exposed workers (MN: 3.06 ± 2.07 ‰, NBUD: 1.38 ± 1.02 ‰) were also significantly higher than in the controls (MN: 1.46 ± 0.64 ‰, P < 0.001; NBUD: 0.70 ± 0.60 ‰, P < 0.001). Additionally, PIG-A MFs showed better associations with several urinary hydroxylated PAH metabolites (P2-OH-Flu = 0.032, r2-OH-Flu = 0. 268; P2-OH-Phe = 0.022, r2-OH-Phe = 0.286; P3-OH-Phe = 0.0312, r3-OH-Phe = 0.270; P4-OH-Phe = 0.018, r4-OH-Phe = 0.296), while the increase in MN, NPB, and NBUD frequencies was not associated with any OH-PAH metabolites; and high-PAH-exposed workers showed the highest PIG-A MFs. Furthermore, there was a significant association between PIG-A MF and PAH exposure levels (Chi-square test for trend, P = 0.006). CONCLUSIONS: Our results indicate that an increase in PIG-A MF in barbecue workers could reflect the response to PAH exposure, providing evidence of its potential as a genotoxicity biomarker in human risk assessment.

Predictors, sources, and health risk of exposure to neonicotinoids in Chinese school children: A biomonitoring-based study.

BACKGROUND: Recent studies have suggested an extensive exposure to neonicotinoids in human, but the information on predictors, sources, and health risk remains limited in children. OBJECTIVE: To explore the predictors, sources, and health risk for exposure of Chinese school children to neonicotinoids by biomonitoring method. METHODS: In 2019, 309 school children aged 7-11 years were selected from a dynamic cohort of children established in Shanghai, East China. Eight neonicotinoids and four metabolites were determined in first morning urine. After detailed information on demographic and socioeconomic indices, intake of drinking water, food consumption, and anthropometric measurements was collected, the predictors and sources of exposure to neonicotinoids were explored by binary and ordinal logistic regression models. Health risk was assessed by the hazard quotient (HQ) and hazard index (HI) based on estimated daily exposure dose. RESULTS: Six neonicotinoids (thiamethoxam, clothianidin, imidacloprid, acetamiprid, nitenpyram, and dinotefuran) and three metabolites (N-desmethyl-thiamethoxam, N-desmethyl-clothianidin, and N-desmethyl-acetamiprid) were detected in 81.3% of urine samples. Children in nuclear family or girls had a higher detection frequency of thiamethoxam. N-desmethyl-acetamiprid was more likely to be detected in children who were older, physically active, or obese. Parents' occupation was heterogeneously associated with the detection of thiamethoxam and clothianidin. Thiamethoxam and clothianidin were more likely to be detected in children consuming more fresh vegetables in all or its specific items of cabbage, nori, and kelp. N-desmethyl-acetamiprid was more likely to be detected in children who drank more tap water. The maximum HQ and HI were 0.3522 and 0.5187, respectively, and 2.8% of children had a HI between 0.1 and 1. CONCLUSION: Predictors for the exposure of children to neonicotinoids included demographic and socioeconomic factors, physical exercise, and relative body weight. Tap water and fresh vegetables were potential sources. A low risk was posed on children's health by the neonicotinoids.

Urinary phthalate metabolites are associated with body mass index and waist circumference in Chinese school children.

BACKGROUND: Lab studies have suggested that ubiquitous phthalate exposures are related to obesity, but relevant epidemiological studies are scarce, especially for children. OBJECTIVE: To investigate the association of phthalate exposures with body mass index (BMI) and waist circumference (WC) in Chinese school children. METHODS: A cross-sectional study was conducted in three primary and three middle schools randomly selected from Changning District of Shanghai City of China in 2011-2012. According to the physical examination data in October, 2011, 124 normal weight, 53 overweight, and 82 obese students 8-15 years of age were randomly chosen from these schools on the basis of BMI-based age- and sex-specific criterion. First morning urine was collected in January, 2012, and fourteen urine phthalate metabolites (free plus conjugated) were determined by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Multiple linear regression was used to explore the associations between naturally log-transformed urine phthalate metabolites and BMI or WC. RESULTS: The urine specific gravity-corrected concentrations of nine urine phthalate metabolites and five molar sums were positively associated with BMI or WC in Chinese school children after adjustment for age and sex. However, when other urine phthalate metabolites were included in the models together with age and sex as covariables, most of these significant associations disappeared except for mono (2-ethylhexyl) phthalate (MEHP) and monoethyl phthalate (MEP). Additionally, some associations showed sex- or age-specific differences. CONCLUSIONS: Some phthalate exposures were associated with BMI or WC in Chinese school children. Given the cross-sectional nature of this study and lack of some important obesity-related covariables, further studies are needed to confirm the associations.