A universal packaging substrate for mechanically stable assembly of stretchable electronics.

Stretchable electronics commonly assemble multiple material modules with varied bulk moduli and surface chemistry on one packaging substrate. Preventing the strain-induced delamination between the module and the substrate has been a critical challenge. Here we develop a packaging substrate that delivers mechanically stable module/substrate interfaces for a broad range of stiff and stretchable modules with varied surface chemistries. The key design of the substrate was to introduce module-specific stretchability and universal adhesiveness by regionally tuning the bulk molecular mobility and surface molecular polarity of a near-hermetic elastic polymer matrix. The packaging substrate can customize the deformation of different modules while avoiding delamination upon stretching up to 600%. Based on this substrate, we fabricated a fully stretchable bioelectronic device that can serve as a respiration sensor or an electric generator with an in vivo lifetime of 10 weeks. This substrate could be a versatile platform for device assembly.

Systemic interindividual DNA methylation variants in cattle share major hallmarks with those in humans.

BACKGROUND: We recently identified ~ 10,000 correlated regions of systemic interindividual epigenetic variation (CoRSIVs) in the human genome. These methylation variants are amenable to population studies, as DNA methylation measurements in blood provide information on epigenetic regulation throughout the body. Moreover, establishment of DNA methylation at human CoRSIVs is labile to periconceptional influences such as nutrition. Here, we analyze publicly available whole-genome bisulfite sequencing data on multiple tissues of each of two Holstein cows to determine whether CoRSIVs exist in cattle. RESULTS: Focusing on genomic blocks with ≥ 5 CpGs and a systemic interindividual variation index of at least 20, our approach identifies 217 cattle CoRSIVs, a subset of which we independently validate by bisulfite pyrosequencing. Similar to human CoRSIVs, those in cattle are strongly associated with genetic variation. Also as in humans, we show that establishment of DNA methylation at cattle CoRSIVs is particularly sensitive to early embryonic environment, in the context of embryo culture during assisted reproduction. CONCLUSIONS: Our data indicate that CoRSIVs exist in cattle, as in humans, suggesting these systemic epigenetic variants may be common to mammals in general. To the extent that individual epigenetic variation at cattle CoRSIVs affects phenotypic outcomes, assessment of CoRSIV methylation at birth may become an important tool for optimizing agriculturally important traits. Moreover, adjusting embryo culture conditions during assisted reproduction may provide opportunities to tailor agricultural outcomes by engineering CoRSIV methylation profiles.

Effect of IL-9 neutralising antibody on pyroptosis via SGK1/NF-κB/NLRP3/GSDMD in allergic rhinitis mice.

Allergic rhinitis is a common non-infectious inflammatory disease that affects approximately 15 % of people worldwide and has a complex and unclear aetiology. In recent years, pyroptosis has been found to play a role in the development of allergic rhinitis. IL-9, pyroptosis, serum and glucocorticoid-induced protein kinase 1 (SGK1), NOD-like receptor 3 (NLRP3), and nuclear factor kappa B (NF-κB) have been shown to influence each other. Herein, we aimed to explore the role of IL-9 neutralising antibody in pyroptosis involving IL-9, SGK1, NF-κB, and NLRP3 in allergic rhinitis. We observed a decrease in cytokines involved in pyroptosis and gasdermin D (GSDMD) compared with those in mice with allergic rhinitis. Further, phosphorylation of NF-κB/p65 decreased compared with that in mice with allergic rhinitis; NLRP3 and ASC also decreased, although the levels were higher than those in controls. SGK1 levels decreased compared with that in mice with allergic rhinitis and increased after using IL-9 neutralising antibodies, thus demonstrating its negative regulatory effects. The IL-9 neutralising antibody reduced the inflammatory and pyroptosis responses via SGK1 and NF-κB/NLRP3/GSDMD pathway. Our research results indicate that IL-9 regulates allergic rhinitis via the influence of SGK1 and NF-κB/NLRP3/GSDMD signalling pathway, providing new insights for developing novel drugs to treat allergic rhinitis.

Stretchable Electrodes with Interfacial Percolation Network.

Stretchable electrodes are an essential component that determines the functionality and reliability of stretchable electronics, but face the challenge of balancing conductivity and stretchability. This work proposes a new conducting concept called the interfacial percolation network (PN) that results in stretchable electrodes with high conductivity, large stretchability, and high stability. The interfacial PN is composed of a 2D silver nanowires (AgNWs) PN and a protruding 3D AgNWs PN embedded on the surface and in the near-surface region of an elastic polymer matrix, respectively. The protruded PN is obtained by changing the arrangements of AgNWs from horizontal to quasi-vertical through introducing foreign polymer domains in the near-surface region of the polymer matrix. The resulting electrode achieves a conductivity of 13 500 S cm-1 and a stretchability of 660%. Its resistance changes under stretched conditions are orders of magnitude lower than those of conventional 2D PN and 2D + 3D PN. An interfacial PN electrode made from liquid metal remained its conductivity at 46 750 S cm-1 after the electrode underwent multiple stretch-release cycles with a deformation of >600%. The concept of interfacial PN provides fruitful implications for the design of stretchable electronics.

Key roles of insulin receptor InR1 in initiating reproductive diapause in males of the cabbage beetle Colaphellus bowringi (Coleoptera: Chrysomelidae).

BACKGROUND: Reproductive diapause serves as a valuable strategy enabling insects to survive unfavorable seasonal conditions. However, forcing insects into diapause when the environment is conducive to their well-being can cause them to miss out on seasonal opportunities for reproduction. This outcome not only reduces insect populations but also minimizes crop losses caused by insect feeding. Therefore, altering the timing of diapause initiation presents a potential strategy for managing pests. In this study, we examined the possible role of the Insulin Receptor 1 (InR1) in controlling reproductive diapause entry in the male cabbage beetle, Colaphellus bowringi. RESULTS: Compared to short-day (SD) conditions, long-day (LD) conditions led to reproductive diapause of C. bowringi males, characterized by arrested gonad development, increased Triglyceride (TG) accumulation, and upregulated expression of diapause protein 1 and genes associated with lipogenesis and stress tolerance. Upon employing RNA interference to knock down InR1 under SD conditions, males destined for reproduction were compelled into diapause, evidenced by arrested gonadal development, accumulation of TG, and elevated expression of diapause-related genes. Intriguingly, despite the common association of the absence of juvenile hormone (JH) with reproductive diapause in females, the knockdown of InR1 in males did not significant affect the expression of JH biosynthesis and JH response gene. CONCLUSION: The study highlight InR1 is a key factor involved in regulating male reproductive diapause in C. bowringi. Consequently, targeting insulin signaling could be a viable approach to perturb diapause timing, offering a promising strategy for managing pests with reproductive diapause capabilities. © 2024 Society of Chemical Industry.

A spatiotemporal molecular atlas of the ovulating mouse ovary.

Ovulation is essential for reproductive success, yet the underlying cellular and molecular mechanisms are far from clear. Here, we applied high-resolution spatiotemporal transcriptomics to map out cell type- and ovulation stage-specific molecular programs as function of time during follicle maturation and ovulation in mice. Our analysis revealed dynamic molecular transitions within granulosa cell types that occur in tight coordination with mesenchymal cell proliferation. We identified molecular markers for the emerging cumulus cell fate during the preantral-to-antral transition. We describe transcriptional programs that respond rapidly to ovulation stimulation and those associated with follicle rupture, highlighting the prominent roles of apoptotic and metabolic pathways during the final stages of follicle maturation. We further report stage-specific oocyte-cumulus cell interactions and diverging molecular differentiation in follicles approaching ovulation. Collectively, this study provides insights into the cellular and molecular processes that regulate mouse ovarian follicle maturation and ovulation with important implications for advancing therapeutic strategies in reproductive medicine.

A Spatiotemporal Molecular Atlas of the Ovulating Mouse Ovary.

Ovulation is essential for reproductive success, yet the underlying cellular and molecular mechanisms are far from clear. Here, we applied high-resolution spatiotemporal transcriptomics to map out cell-type- and ovulation-stage-specific molecular programs as function of time during follicle maturation and ovulation in mice. Our analysis revealed dynamic molecular transitions within granulosa cell types that occur in tight coordination with mesenchymal cell proliferation. We identified new molecular markers for the emerging cumulus cell fate during the preantral-to-antral transition. We describe transcriptional programs that respond rapidly to ovulation stimulation and those associated with follicle rupture, highlighting the prominent roles of apoptotic and metabolic pathways during the final stages of follicle maturation. We further report stage-specific oocyte-cumulus cell interactions and diverging molecular differentiation in follicles approaching ovulation. Collectively, this study provides insights into the cellular and molecular processes that regulate mouse ovarian follicle maturation and ovulation with important implications for advancing therapeutic strategies in reproductive medicine.

Effects of Gibberellin Pre-Treatment on Seed Germination and Seedling Physiology Characteristics in Industrial Hemp under Drought Stress Condition.

The present study aimed to explore the effects of exogenous gibberellins (GAs) on seed germination and subsequent seedling growth of hemp (Cannabis sativa L.) under drought stress. Seeds of two industrial hemp cultivars i.e., 'Yunma 1', (YM) and 'Bamahuoma', (BM) were treated with different concentrations of GA3 solution (0, 200, 400, 600, 800 mg/L) at 20 °C for 8 h. The effect of pre-treatment was assessed on germination characteristics and physiological indexes on subsequent exposure to drought stress using 20% (m/v) polyethylene glycol (PEG) for 7 days. The results revealed that seed germination in hemp was sensitive to drought stress, as the germination indexes (germination rate and germination potential) decreased significantly, and seedling growth (hypocotyl length and radicle length) was impeded under 20% PEG-6000 condition. GA3 pre-treatment affected germination rate, germination potential, hypocotyl length and radicle length. With increasing GA3 concentration, these indexes first increased and then decreased. For seedling physiology characteristics in hemp, GA3-pretreatment remarkedly increased the osmotic regulating substances (soluble sugar and soluble protein contents) and the activities of antioxidant enzymes (SOD, superoxide dismutase and POD, peroxidase), while sharply decreased the lipid peroxidation (malondialdehyde, MDA) in seedlings grown under PEG-6000 induced drought stress. These results suggested that seeds pre-treated with GA3 could enhance the drought tolerance of hempseeds, and the optimal effect of GA3 for seed pre-treatment of YM and BM could be obtained when the concentration of GA3 solution reached 400 mg/L and 600 mg/L, respectively.

Recent progress in performance optimization of Cu-SSZ-13 catalyst for selective catalytic reduction of NO x.

Nitrogen oxides (NO x ), which are the major gaseous pollutants emitted by mobile sources, especially diesel engines, contribute to many environmental issues and harm human health. Selective catalytic reduction of NO x with NH3 (NH3-SCR) is proved to be one of the most efficient techniques for reducing NO x emission. Recently, Cu-SSZ-13 catalyst has been recognized as a promising candidate for NH3-SCR catalyst for reducing diesel engine NO x emissions due to its wide active temperature window and excellent hydrothermal stability. Despite being commercialized as an advanced selective catalytic reduction catalyst, Cu-SSZ-13 catalyst still confronts the challenges of low-temperature activity and hydrothermal aging to meet the increasing demands on catalytic performance and lifetime. Therefore, numerous studies have been dedicated to the improvement of NH3-SCR performance for Cu-SSZ-13 catalyst. In this review, the recent progress in NH3-SCR performance optimization of Cu-SSZ-13 catalysts is summarized following three aspects: 1) modifying the Cu active sites; 2) introducing the heteroatoms or metal oxides; 3) regulating the morphology. Meanwhile, future perspectives and opportunities of Cu-SSZ-13 catalysts in reducing diesel engine NO x emissions are discussed.

An Explainable AI Approach for the Rapid Diagnosis of COVID-19 Using Ensemble Learning Algorithms.

Background: Artificial intelligence-based disease prediction models have a greater potential to screen COVID-19 patients than conventional methods. However, their application has been restricted because of their underlying black-box nature. Objective: To addressed this issue, an explainable artificial intelligence (XAI) approach was developed to screen patients for COVID-19. Methods: A retrospective study consisting of 1,737 participants (759 COVID-19 patients and 978 controls) admitted to San Raphael Hospital (OSR) from February to May 2020 was used to construct a diagnosis model. Finally, 32 key blood test indices from 1,374 participants were used for screening patients for COVID-19. Four ensemble learning algorithms were used: random forest (RF), adaptive boosting (AdaBoost), gradient boosting decision tree (GBDT), and extreme gradient boosting (XGBoost). Feature importance from the perspective of the clinical domain and visualized interpretations were illustrated by using local interpretable model-agnostic explanations (LIME) plots. Results: The GBDT model [area under the curve (AUC): 86.4%; 95% confidence interval (CI) 0.821-0.907] outperformed the RF model (AUC: 85.7%; 95% CI 0.813-0.902), AdaBoost model (AUC: 85.4%; 95% CI 0.810-0.899), and XGBoost model (AUC: 84.9%; 95% CI 0.803-0.894) in distinguishing patients with COVID-19 from those without. The cumulative feature importance of lactate dehydrogenase, white blood cells, and eosinophil counts was 0.145, 0.130, and 0.128, respectively. Conclusions: Ensemble machining learning (ML) approaches, mainly GBDT and LIME plots, are efficient for screening patients with COVID-19 and might serve as a potential tool in the auxiliary diagnosis of COVID-19. Patients with higher WBC count, higher LDH level, or higher EOT count, were more likely to have COVID-19.

Effects of IGF-1 on the Three-Dimensional Culture of Ovarian Preantral Follicles and Superovulation Rates in Mice.

Insulin-like growth factor-1 (IGF-1) plays a crucial role during folliculogenesis, which has been demonstrated by previous research. However, the optimal IGF-1 dosage in the three-dimensional (3D) culture system is unknown. Mouse secondary follicles (140−150 µm) were cultured for 6 days within an alginate bead in a medium supplemented with 0 (G0), 5 ng/mL (G5), 10 ng/mL (G10), or 50 ng/mL IGF-1 (G50). Secretions of 17ß-estradiol and progesterone were significantly increased in G10 and G50 (p < 0.05). However, G50 significantly inhibited follicular growth (p < 0.05), while G10 showed a higher oocyte maturation rate. Thus, the 10 ng/mL IGF-1 was used in subsequent experiments. IGF-1 enhanced the function of granulosa cells (GCs) by upregulating expressions of Star, Cyp19a1, Hsd3b1, Fshr, and Lhcgr. Oocyte secretory function was promoted by upregulating expressions of Bmp-15, Gdf-9, and Fgf-8. Addition of IGF-1 showed anti-apoptotic effect. However, G10 did not improve fertilization rate of MII oocytes compared to G0. In an intraperitoneal injection experiment in mice, IGF-1 significantly increased the number of ovulated oocytes (p < 0.05). In conclusion, 10 ng/mL IGF-1 can promote the production of mature oocytes in the 3D culture medium and injection of IGF-1 before superovulation increases the number of ovulated oocytes.

Fate of the neonicotinoid insecticide cycloxaprid in different soils under oxic conditions.

Neonicotinoids are the most widely used pesticides worldwide due to their high toxicity to invertebrates. However, these compounds also increase the probability of environmental contamination. Cycloxaprid (CYC) is a promising neonicotinoid due to its insecticidal effectiveness and low cross resistance, but little is known about its fate in soils. Using radioisotope tracing techniques, the fate of 14C-labeled CYC enantiomers and racemic mixtures in aerobic soil was investigated in this research. After 100 d of incubation, the extractable residue (ER) of CYC decreased from 89.6% to 36.4% in red clay soil, from 46.1% to 10.1% in yellow loam soil, and from 93.2% to 12.2% in coastal saline soil. The radioactivity was substantially lower in methanol than in the other two solvents, but the distribution of CYC ER in various solvents across the three soils dramatically differed. The fraction of radioactive CYC that diffused into bound residue (BR) in the three soils increased over time to 56.8-83.0%. The variability in BR was influenced by soil properties such as organic matter concentration, pH, and residual microbial activity. Among the soils, yellow loam soil had the greatest tendency (53.0-83.0%) to form BR, while red clay soil showed the lowest capacity (7.5-61.2%). Cumulative mineralization (MI) to 14CO2 accounted for 0.12-0.23%, 6.69-7.31% and 14.82-20.06% in acidic soil, neutral soil and alkaline soil, respectively, which suggests that the environmental fate of chiral pesticides may be influenced by soil pH. No stereoselective behavior was detected in this study. These findings provide a framework to assess the environmental impact and ecological safety of CYC application.

Graph neural network and multi-data heterogeneous networks for microbe-disease prediction.

The research on microbe association networks is greatly significant for understanding the pathogenic mechanism of microbes and promoting the application of microbes in precision medicine. In this paper, we studied the prediction of microbe-disease associations based on multi-data biological network and graph neural network algorithm. The HMDAD database provided a dataset that included 39 diseases, 292 microbes, and 450 known microbe-disease associations. We proposed a Microbe-Disease Heterogeneous Network according to the microbe similarity network, disease similarity network, and known microbe-disease associations. Furthermore, we integrated the network into the graph convolutional neural network algorithm and developed the GCNN4Micro-Dis model to predict microbe-disease associations. Finally, the performance of the GCNN4Micro-Dis model was evaluated via 5-fold cross-validation. We randomly divided all known microbe-disease association data into five groups. The results showed that the average AUC value and standard deviation were 0.8954 ± 0.0030. Our model had good predictive power and can help identify new microbe-disease associations. In addition, we compared GCNN4Micro-Dis with three advanced methods to predict microbe-disease associations, KATZHMDA, BiRWHMDA, and LRLSHMDA. The results showed that our method had better prediction performance than the other three methods. Furthermore, we selected breast cancer as a case study and found the top 12 microbes related to breast cancer from the intestinal flora of patients, which further verified the model's accuracy.

FSH Promotes Progesterone Synthesis by Enhancing Autophagy to Accelerate Lipid Droplet Degradation in Porcine Granulosa Cells.

Little is known about the molecular relationships among follicle stimulating hormone (FSH), lipid droplet (LD) degradation, and autophagy. In this study, we aimed to investigate the pathway by which FSH regulates autophagy and the potential role of autophagy in progesterone production. Our results revealed that FSH stimulated progesterone production in mammalian follicular granulosa cells (GCs) through a non-canonical pathway. In porcine secondary follicles cultured in vitro, FSH treatment increased the level of the autophagic marker, LC3-II, as well as increased the number of autophagic vacuoles in GCs. The underlying molecular mechanism and biological functions were then investigated in porcine GCs. Our results demonstrated that FSH could upregulate Beclin1 levels in porcine GCs; however, this effect was blocked by LY294002 (a PI3K/AKT inhibitor) and SP600125 (SAPK/JNK inhibitor). Further research confirmed that the transcriptional factor, c-Jun, was phosphorylated by FSH, then translocated into the nucleus from the cytoplasm and bound to the BECLIN1 promoter region, and that LY294002, SP600125, or c-Jun knockdown prevented the increase in Beclin1 levels induced by FSH. Interestingly, inhibition of autophagy using chloroquine or SP600125 decreased progesterone production in porcine GCs treated with FSH, although the expression of StAR and P450scc was not disturbed. Moreover, FSH treatment reduced the average number and size of LDs in porcine GCs, but these effects were eliminated by knocking down the key autophagy genes, ATG5 and BECLIN1; in addition, the effect of FSH on promoting progesterone secretion by the cells was also reduced significantly. Based on the above results, we concluded that FSH promoted progesterone production by enhancing autophagy through upregulation of Beclin1 via the PI3K/JNK/c-Jun pathway to accelerate LD degradation in porcine GCs, independent of the classical steroidogenic pathway.

[Corncornin-3-O-glucoside mediates the NF-κB pathway to inhibit H_2O_2-induced apoptosis].

OBJECTIVE: To study the anti-apoptotic effect of cyanidin-3-O-glucoside(C3 G) on H_2O_2-induced injury in human embryonic kidney(HEK)-293 cells. METHODS: Hydrogen peroxide induced injury of HEK-293 cell was used as the research object. HEK-293 cells were pretreated with different concentrations of C3 G(1. 25, 5, 20 µmol/L). The anti-apoptotic effects of C3 G on injured cells were examined by the release rates of LDH and mitochondrial membrane potential(MMP). Western blot and qRT-PCR were used to detect the protein expression and mRNA expression of NF-κB P65. RESULTS: The result showed that the release rate of LDH was increased, MMP was decreased, the protein and mRNA of P65 was increased after H_2O_2 inducing. Whereas, the release rates of LDH were significantly lower than that of the injured group after 1. 25, 5, 20 µmol/L C3 G pretreatment of injured cells(P<0. 05). The MMP of C3 G group was significantly higher than injured group with concentration-dependent increases. The proteins and mRNA of P65 were also significantly lower than that of injured group(P<0. 05). CONCLUSION: Cyanidin-3-O-glucoside shows anti-apoptotic effect on H_2O_2-induced injury in HEK-293 cell. The mechanisms of anti-apoptotic effects may be to achieve by protecting cell biofilms, and inhibiting the activity of NF-κB signaling pathway.

Early cleavage of preimplantation embryos is regulated by tRNAGln-TTG-derived small RNAs present in mature spermatozoa.

tRNA-derived small RNAs (tsRNAs) from spermatozoa could act as acquired epigenetic factors and contribute to offspring phenotypes. However, the roles of specific tsRNAs in early embryo development remain to be elucidated. Here, using pigs as a research model, we probed the tsRNA dynamics during spermatogenesis and sperm maturation and demonstrated the delivery of tsRNAs from semen-derived exosomes to spermatozoa. By microinjection of antisense sequences into in vitro fertilized oocytes and subsequent single-cell RNA-seq of embryos, we identified a specific functional tsRNA group (termed here Gln-TTGs) that participate in the early cleavage of porcine preimplantation embryos, probably by regulating cell cycle-associated genes and retrotransposons. We conclude that specific tsRNAs present in mature spermatozoa play significant roles in preimplantation embryo development.

Birth month associates with risk of coronary artery disease and its complications: A propensity score matched analysis.

OBJECTIVE: Birth month and climate affect lifetime disease risk, while the underlying mechanisms remain largely elusive. It is vital to investigate the risks of coronary artery disease (CAD) and its complications in patients born in different months. METHODS: A total of 12,263 patient medical records were reviewed from the BioBank of First Affiliated Hospital of Xinxiang Medical University, with 4729 records from patients with CAD (CAD group) and 7534 records from control patients without CAD (control group). Two groups of patients were matched by the propensity score matched method. Birth months were compared between two groups of patients. The relationships between birth month and the numbers of CAD and its complications were also investigated. Interestingly, we also explore the relationship between the birth seasons and the numbers of CAD and its complications. RESULTS: Compared to control, CAD group had greater CAD risks for patients born in November (OR 1.390, 95% CI 1.090-1.772), December (OR 1.358, 95% CI 1.067-1.730), and February (OR 1.332, 95% CI 1.043-1.700) compared to those born in May. Compared to patients born in December, patients born in January to March and May to September had greater risk of heart failure (P<0.05). There was no difference in the incidence of myocardial infarction, conduction block, and atrial fibrillation across birth months (P>0.05). In terms of birth season, patients born in winter have greater CAD risk than those born in spring (OR 1.247, 95% CI 1.075-1.447). And there was no difference in the incidence of CAD complications across with birth seasons (P>0.05). CONCLUSIONS: There was a correlation between birth month and CAD. People born in November, December, and February had greater CAD risk, and people born in winter had greater CAD risk. Among CAD patients, those born in January to March and May to September had the greater risk of heart failure.

Effects of Transgenic Bt Rice Containing the Cry1Ab Protein on the Gastrointestinal Health of Highly Inbred Wuzhishan Pigs after Two Generations of Feeding.

To assess the safety of transgenic Bt rice, we evaluated the chronic effects of Bt rice carrying the Cry1Ab protein (1.64 mg/kg) on the gut microbiota and histopathology in highly inbred Wuzhishan pigs (WZSP) in a two-generation feeding study. The WZSP of the f0 ( n = 26) and f1 ( n = 27) generations were divided into GM and Non-GM groups and fed for 360 and 420 days with Bt and isogenic parent-line rice, respectively. The high-throughput 16S rRNA gene sequencing results revealed that the relative abundance of the family Enterobacteriaceae and genus Escherichia were significantly different between f1F and f1Z. The level of the genera CF231 and SMB53 in the f0Z group was higher than that in the f0F group. In addition, no abnormal histopathology changes in the main gastrointestinal tissues were found after feeding with Bt rice. In conclusion, Bt rice consumption has no adverse effects on the gut microbiota or organ function of WZSP.

Non-stereoselective transformation of the chiral insecticide cycloxaprid in aerobic soil.

Cycloxaprid (CYC) is one of the most effective neonicotinoid insecticides and is proposed to be a replacement of imidacloprid that has caused concerns over non-targeted resistance and ecological toxicity worldwide. The present study was performed with the 14C-labeled racemic CYC and its two enantiomers in aerobic soil. Racemic CYC and the enantiomers 1S2R-CYC and 1R2S-CYC underwent non-stereoselective degradation in the three soils tested. During the incubation period, CYC was transformed into three achiral degradation products which displayed varying degradation kinetics dependent upon soil properties. The soil properties were found to significantly influence the CYC metabolite profiles. The fastest degradation occurred in loamy soil, whereas the slowest reactions occurred in acidic clay soil. The primary transformation of CYC included cleavage of the oxabridged seven-member ring and CN between chloropyridinylmethyl and imidazalidine ring, carboxylation of the alkene group, and hydroxylation of imidazolidine ring. The results shed light on understanding of CYC degradation and provided useful information for applications and environmental assessments of chiral pesticides.

Assessment of the environmental fate of cycloxaprid in flooded and anaerobic soils by radioisotopic tracing.

Cycloxaprid (CYC) is a novel broad-spectrum neonicotinoid insecticide that has been developed for agricultural pest control. The fate of the (14)C-labeled racemic and enantio-pure CYC isomers in flooded and anaerobic soil was investigated using radioisotope tracing techniques. After 100 d of incubation, only a minor portion (<1%) of the applied CYC isomers is mineralized by each of the four tested soil types. The fraction of initially applied radioactive CYC dissipated into the bound or non-extractable residues (BR) increases with increase in the length of the incubation period, reaching up to 53.0-81.6%. The dissipation of the CYC through mineralization or formation of BR is strongly influenced by soil properties, such as humic content, pH value, and retained microbial activity. Amongst the soils studied, the fluvio-marine yellow loamy soil displayed the highest tendency to mineralize CYC while the coastal saline soil exhibited the strongest tendency to form BR. The observation that the water phase retained the large portion(>60%) of the radioactivity attributed to the total extractable residue suggested that under the experimental condition, the initially applied (14)C-labeled CYC residues were readily available for leaching or offsite transport. Additionally, no enantiomer-specific behaviors are observed. The results from this study provide a framework for assessing the environmental impact resulting from the use of this pesticide.