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Recurrent miscarriage (RM) is related to the dysfunction of extravillous trophoblast cells (EVTs), but the comprehensive mechanisms remain largely unexplored. We analyzed single-cell RNA sequencing (scRNA-seq), bulk RNA sequencing and microarray datasets obtained from Gene Expression Omnibus (GEO) database to explore the hub genes in the mechanisms of RM. We identified 1724 differentially expressed genes (DEGs) in EVTs from the RM, and they were all expressed along the trajectory of EVTs. These DEGs were associated with hypoxia and glucose metabolism. Single-cell Regulatory Network Inference and Clustering (SCENIC) analysis revealed that E2F transcription factor (E2F) 8 (E2F8) was a key transcription factor for these DEGs. And the expression of ENO1 can be positively regulated by E2F8 via RNA sequencing analysis. Subsequently, we performed immunofluorescence assay (IF), plasmid transfection, western blotting, chromatin immunoprecipitation (ChIP), real-time quantitative polymerase chain reaction (qRT-PCR), and transwell assays for validation experiments. We found that the expression of alpha-Enolase 1 (ENO1) was lower in the placentas of RM. Importantly, E2F8 can transcriptionally regulate the expression of ENO1 to promote the invasion of trophoblast cells by inhibiting secreted frizzled-related protein 1/4 (SFRP1/4) to activate Wnt signaling pathway. Our results suggest that ENO1 can promote trophoblast invasion via an E2F8-dependent manner, highlighting a potential novel target for the physiological mechanisms of RM.
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Aborto Habitual , Proteínas de Ligação a DNA , Proteínas Repressoras , Trofoblastos , Adulto , Feminino , Humanos , Gravidez , Aborto Habitual/metabolismo , Aborto Habitual/genética , Aborto Habitual/patologia , Movimento Celular , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Fosfopiruvato Hidratase/metabolismo , Fosfopiruvato Hidratase/genética , Trofoblastos/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Repressoras/metabolismoRESUMO
Preeclampsia is a gestational disease characterized by two major pathological changes-shallow trophoblast invasion and impaired spiral artery remodeling. Atrial natriuretic peptide (ANP) is a kind of peptide hormone that regulates blood pressure, while the lack of active ANP participates in preeclampsia pathogenesis. However, the underlying mechanism of how ANP modulates trophoblasts function remains unclarified. Here, we performed isobaric tags for relative and absolute quantification (iTRAQ) in ANP-treated HTR-8/SVneo cells and identified Protein Kinase 3 (PKN3) as the downstream factor of ANP, which was downregulated in preeclamptic placenta. Chromatin immunoprecipitation analysis and luciferase assays showed that NFYA was one of the transcription factors for the PKN3 promoter, which was also regulated by ANP treatment in HTR-8/SVneo cells. Transmission electron microscopy and Western Blotting in HTR-8/SVneo cells indicated that ANP inhibited autophagy via AMPK-mTORC1 signaling, while excess autophagy was observed in preeclamptic placenta. The increased expression of PKN3 and enhanced cell invasion ability in HTR-8/SVneo cells induced by ANP could be abolished by autophagy activation or transfection with PKN3 shRNA or NFYA shRNA or NPR-A shRNA via regulating the invasion-related genes and the epithelial mesenchymal transition molecules. Our results demonstrated that ANP could enhance trophoblast invasion by upregulating PKN3 via NFYA promotion through autophagy inhibition in an AMPK/mTORC1 signaling-dependent manner.
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Pré-Eclâmpsia , Feminino , Humanos , Gravidez , Proteínas Quinases Ativadas por AMP/metabolismo , Autofagia , Linhagem Celular , Movimento Celular , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Placenta/metabolismo , Pré-Eclâmpsia/metabolismo , RNA Interferente Pequeno/metabolismo , Trofoblastos/metabolismo , Fator Natriurético AtrialRESUMO
In brief: Preeclampsia (PE) is a severe complication that leads to major maternal and fetal mortality and morbidity, and one of its causes is extravillous trophoblast (EVT) dysfunction. This study revealed the role of CD74 in the invasion and proliferation of EVTs. Abstract: PE is a severe hypertensive disorder during pregnancy, and one of its causes is the dysfunction of EVTs. In this study, we analyzed single-cell RNA sequencing (scRNA-seq) data of placentas from PE patients and the sirtuin 1 (SIRT1) heterozygous knockout mouse model, which exhibited typical PE-like symptoms. We identified 134 differentially expressed genes (DEGs) with similar trends in EVTs of PE patients and in parietal trophoblast giant cells (P-TGCs) of Sirt1-/- (HO) placentas from Sirt1+/- (HE) pregnant mice. Interestingly, Kyoto Encyclopedia of Genes and Genomes analysis showed that 134 overlapping genes were related to the MAPK signaling pathway. We validated several DEGs using immunofluorescence at the protein level. Finally, we selected CD74 for further experiments, which showed a decrease in EVTs of PE patients and in P-TGCs of Sirt1-/- placentas from Sirt1+/- pregnant mice. Additionally, cell proliferation assays and transwell assays showed that the proliferation and invasion abilities were decreased in CD74 knockdown HTR8/SVneo cells using lentivirus transfection, which can be improved by adding the SIRT1 agonist SRT1720 or metformin, an agonist of the MAPK signaling pathway. Importantly, the expression of CD74 can be positively regulated by SIRT1. These data suggest that CD74 plays an important protective role in the pathogenesis of preeclampsia by regulating the MAPK signaling pathway, which can be regulated by SIRT1.
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Pré-Eclâmpsia , Trofoblastos , Gravidez , Feminino , Humanos , Camundongos , Animais , Trofoblastos/metabolismo , Sirtuína 1/genética , Sirtuína 1/metabolismo , Pré-Eclâmpsia/patologia , Placenta/metabolismo , Proliferação de Células , Movimento CelularRESUMO
Recurrent miscarriage (RM) is a pregnancy complication associated with dysregulation of the maternal-fetal interface. We aimed to identify dysfunctional interactions between trophoblast cells and decidual immune cells in RM. We downloaded single-cell RNA sequencing (scRNA-seq) datasets (GSE214607) from the Gene Expression Omnibus (GEO) datasets for further analysis using the R software. The data comprised of paired placental and decidual tissues, including those from patients diagnosed with RM and matched healthy controls. A total of 22976 cells were identified in 11 cell types, including trophoblasts, immune cells, and other cells. We divided trophoblast cells into three types and analyzed their interactions with decidual immune cells. Additionally, we re-clustered NK&T cells and macrophages, identified differentially expressed genes (DEGs), enriched their functions, and compared the cell interactions with trophoblast cells in each cell type. Our single-cell atlas of the maternal-fetal interface revealed alterations in the cellular organization of the decidua and placenta, cell type-specific transcriptome, and cell communication between immune and non-immune cells in RM, which are critical for illuminating the pathophysiology of RM.
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Aborto Habitual , Placenta , Gravidez , Humanos , Feminino , Placenta/metabolismo , Trofoblastos , Decídua/metabolismo , Aborto Habitual/genética , Aborto Habitual/metabolismo , Primeiro Trimestre da GravidezRESUMO
Background: Fetal growth restriction (FGR) is characterized by restricted fetal growth and dysregulated placental development. The etiology and pathogenesis still remain elusive. IL-27 shows multiple roles in regulating various biological processes, however, how IL-27 involves in placentation in FGR pregnancy hasn't been demonstrated. Methods: The levels of IL-27 and IL-27RA in FGR and normal placentae were determined by immunohistochemistry, western blot and RT-PCR. HTR-8/SVneo cells and Il27ra-/- murine models have been adopted to evaluate the effects of IL-27 on the bio-functions of trophoblast cells. GO enrichment and GSEA analysis were performed to explore the underlying mechanism. Findings: IL-27 and IL-27RA was lowly expressed in FGR placentae and administration of IL-27 on HTR-8/SVneo could promote its proliferation, migration and invasion. Comparing with wildtypes, Il27ra-/- embryos were smaller and lighter, and the placentae from which were poorly developed. In mechanism, the molecules of canonical Wnt/ß-catenin pathway (CCND1, CMYC, SOX9) were downregulated in Il27ra-/- placentae. In contrast, the expression of SFRP2 (negative regulator of Wnt) was increased. Overexpression of SFRP2 in vitro could impair trophoblast migration and invasion capacity. Interpretation: IL-27/IL-27RA negatively regulates SFRP2 to activate Wnt/ß-catenin, and thus promotes migration and invasion of trophoblasts during pregnancy. However, IL-27 deficiency may contribute to the development of FGR by restricting the Wnt activity.
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Interleucina-27 , Gravidez , Feminino , Animais , Camundongos , Humanos , Trofoblastos , beta Catenina/genética , Retardo do Crescimento Fetal/genética , Placenta , Proliferação de Células/genética , Proteínas de MembranaRESUMO
BACKGROUND: Autism spectrum disorder (ASD) is a neurodevelopmental disorder that can cause difficulty with communication and social interactions as well as complicated family dynamics. Digital health interventions can reduce treatment costs and promote healthy lifestyle changes. These therapies can be adjunctive or replace traditional treatments. However, issues with cooperation and compliance prevent preschool patients with ASD from applying these tools. In this open-label, randomized controlled trial, we developed a nonwearable digital therapy called virtual reality-incorporated cognitive behavioral therapy (VR-CBT). OBJECTIVE: The aim of this study was to assess the adjunctive function of VR-CBT by comparing the effects of VR-CBT plus learning style profile (LSP) intervention with those of LSP-only intervention in preschool children with ASD. METHODS: This trial was performed in China on 78 preschool children (age 3-6 years, IQ>70) diagnosed with ASD who were randomized to receive a 20-week VR-CBT plus LSP intervention (intervention group, 39/78, 50%) or LSP intervention only (control group, 39/78, 50%). The primary outcome was the change of scores from baseline to week 20, assessed by using the parent-rated Autism Behavior Checklist (ABC). Secondary outcomes included the Childhood Autism Rating Scale (CARS), Attention-Deficit/Hyperactivity Disorder Rating Scale-IV (ADHD-RS-IV), and behavioral performance data (accuracy and reaction time) in go/no-go tasks. All primary and secondary outcomes were analyzed in the intention-to-treat population. RESULTS: After the intervention, there was an intervention effect on total ABC (ß=-5.528; P<.001) and CARS scores (ß=-1.365; P=.02). A similar trend was observed in the ABC subscales: sensory (ß=-1.133; P=.047), relating (ß=-1.512; P=.03), body and object use (ß=-1.211; P=.03), and social and self-help (ß=-1.593; P=.03). The intervention also showed statistically significant effects in improving behavioral performance (go/no-go task, accuracy, ß=2.923; P=.04). Moreover, a significant improvement of ADHD hyperactivity-impulsivity symptoms was observed in 53 children with comorbid ADHD based on ADHD-RS-IV (ß=-1.269; P=.02). No statistically significant intervention effect was detected in the language subscale of ABC (ß=-.080; P=.83). Intervention group girls had larger improvements in ABC subscales, that is, sensory and body and object use and in the CARS score and accuracy of go/no-go task (all P<.05) than the control group girls. Statistically significant intervention effects could be observed in hyperactivity-impulsivity symptoms in the intervention group boys with comorbid ADHD compared with those in the control group boys (ß=-1.333; P=.03). CONCLUSIONS: We found potentially positive effects of nonwearable digital therapy plus LSP on core symptoms associated with ASD, leading to a modest improvement in the function of sensory, motor, and response inhibition, while reducing impulsivity and hyperactivity in preschoolers with both ASD and ADHD. VR-CBT was found to be an effective and feasible adjunctive digital tool. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100053165; http://www.chictr.org.cn/showproj.aspx?proj=137016.
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Transtorno do Espectro Autista , Terapia Cognitivo-Comportamental , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Povo Asiático , Transtorno do Espectro Autista/terapia , Transtorno Autístico , China , Terapia de Exposição à Realidade VirtualRESUMO
A negatively charged boron vacancy (VB-) color center in hexagonal boron nitride has recently been proposed as a promising quantum sensor due to its excellent properties. However, the spin level structure of the VB- color center is still unclear, especially for the excited state. Here we measured and confirmed the excited-state spin transitions of VB- using an optically detected magnetic resonance (ODMR) technique. The zero-field splitting of the excited state is 2.06 GHz, the transverse splitting is 93.1 MHz, and the g factor is 2.04. Moreover, negative peaks in fluorescence intensity and ODMR contrast at the level anticrossing point were observed, and they further confirmed that the spin transitions we measured came from the excited state. Our work deepens the understanding of the excited-state structure of VB- and promotes VB--based quantum sensing applications.
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Preeclampsia (PE) is one of the pregnancy complications, leading to major maternal and fetal morbidity and mortality; however, the underlying mechanisms of PE still remain unclear. We aimed to explore the role of apolipoprotein A1 (APOA1) in the pathophysiology of PE. The expression of APOA1 was elevated in both plasma and placental tissues, as detected by Western blotting, immunohistochemistry, and a qRT-PCR assay. Importantly, we detected the concentration of APOA1 using the ELISA assay in normal control women (n = 30) and women with preeclampsia (n = 29) from a prospective cohort study. The concentration of APOA1 was not significantly altered in plasma during early and mid-term gestation of the PE patients compared to the NP patients; however, it was elevated during late gestation. Additionally, the concentration of APOA1 was positively associated with systolic blood pressure during late gestation. The proliferation and invasion of trophoblast were all increased in HTR8/SVneo cells transfected with APOA1 siRNA and decreased in HTR8/SVneo cells treated with the recombinant human APOA1 protein (rhAPOA1). Additionally, we used public datasets to investigate the downstream genes of APOA1 and qRT-PCR for validation. Furthermore, we explored the transcriptional activity of peroxisome proliferator-activated receptor gamma (PPARγ) in APOA1 by using a luciferase assay, which showed that the APOA1 promoter was activated by PPARγ. Additionally, the inhibitory effect of rhAPOA1 on the ability of trophoblast invasion and proliferation can be rescued by the PPARγ inhibitor. Our findings suggest the crucial role of APOA1 in PE, which might provide a new strategy for the prevention and treatment of PE.
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Placenta , Pré-Eclâmpsia , Gravidez , Humanos , Feminino , Placenta/metabolismo , Pré-Eclâmpsia/metabolismo , Apolipoproteína A-I/genética , Apolipoproteína A-I/metabolismo , PPAR gama/metabolismo , Estudos Prospectivos , Trofoblastos/metabolismo , Movimento Celular , Proliferação de Células/genéticaRESUMO
Pre-eclampsia is a severe pregnant complication, mainly characterized by insufficient trophoblast invasion, impaired uterine spiral artery remodeling, placental hypoxia and ischemia, and endothelial dysfunction. However, the potential mechanisms of pre-eclampsia remain unclear. SIRT1 is a NAD+-dependent deacetylase, involving in multiple biological processes, including energy metabolism, oxidative stress, inflammatory response, and cellular autophagy. Several studies showed that SIRT1 might play a vital role in the pathogenesis of pre-eclampsia. In this review, we aim to integrate the latest research on SIRT1 and pre-eclampsia to explore the comprehensive mechanisms of SIRT1 in pre-eclampsia. More specifically, SIRT1 might affect placental development and trophoblast invasion through autophagy and senescence in pre-eclampsia, and SIRT1 protects vascular endothelial cells from oxidative stress, inflammatory response, autophagy, and senescence. Furthermore, SIRT1 deficiency mice showed typical pre-eclampsia-like performances, which can be reversed via direct SIRT1 supplement or SIRT1 agonist treatment. Additionally, resveratrol, a SIRT1 agonist, attenuates vascular endothelial injury and placental dysfunction, and exerts protective effect on decreasing blood pressure. In this review, we provide new insights into the development of pre-eclampsia, which can establish a theoretical basis for prevention and treatment for pre-eclampsia. Besides, we also propose questions that still need to be further addressed in order to elucidate the comprehensive molecular mechanisms of pre-eclampsia in the future.
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Pré-Eclâmpsia , Animais , Células Endoteliais/patologia , Feminino , Humanos , Placenta/metabolismo , Pré-Eclâmpsia/tratamento farmacológico , Gravidez , Sirtuína 1/metabolismo , TrofoblastosRESUMO
A method for analyzing the influence of velocity changes on metal signals of different materials in oil detection technology is proposed. The flow rate of metal contaminants in the oil will have a certain impact on the sensitivity of the output particle signal in terms of electromagnetic fields and circuits. The detection velocity is not only related to the sensitivity of the output particle signal, but also to the adaptability of high-speed and high-throughput in oil online monitoring. In this paper, based on a high-sensitivity inductive bridge, the eddy current effect of velocity in a time-harmonic magnetic field is theoretically analyzed and experimentally verified, the phenomenon of particle signal variation with velocity for different materials is analyzed and discussed, and finally the effect of velocity on the output signal of the processing circuit is also elaborated and experimentally verified. Experiments show that under the influence of the time-harmonic magnetic field, the increase of the velocity enhances the detection sensitivity of non-ferromagnetic metal particles and weakens the detection sensitivity of non-ferromagnetic particles. Under the influence of the processing circuit, different velocities will produce different signal gains, which will affect the stability of the signal at different velocities.
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The PROSPECT leaf optical radiative transfer models, including PROSPECT-MP, have addressed the contributions of multiple photosynthetic pigments (chlorophyll a and b, and carotenoids) to leaf optical properties, but photo-protective pigment (anthocyanins), another important indicator of vegetation physiological and ecological functions, has not been simultaneously combined within a leaf optical model. Here, we present a new calibration and validation of PROSPECT-MP+ that separates the contributions of multiple photosynthetic and photo-protective pigments to leaf spectrum in the 400-800 nm range using a new empirical dataset that contains multiple photosynthetic and photo-protective pigments (LOPEX_ZJU dataset). We first provide multiple distinct in vivo individual photosynthetic and photo-protective pigment absorption coefficients and leaf average refractive index of the leaf interior using the LOPEX_ZJU dataset. Then, we evaluate the capabilities of PROSPECT-MP+ for forward modelling of leaf directional hemispherical reflectance and transmittance spectra and for retrieval of pigment concentrations by model inversion. The main result of this study is that the absorption coefficients of chlorophyll a and b, carotenoids, and anthocyanins display the physical principles of absorption spectra. Moreover, the validation result of this study demonstrates the potential of PROSPECT-MP+ for improving capabilities in remote sensing of leaf photosynthetic pigments (chlorophyll a and b, and carotenoids) and photo-protective pigment (anthocyanins).
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Antocianinas , Carotenoides , Clorofila , Clorofila A , Folhas de Planta/fisiologiaRESUMO
Metallic contaminants (solid) are generated by friction pair, causing wear of equipment by enters the lubricating system. This poses a great potential threat to the normal operation of such machines. The timely analysis and detection of debris can lead to the avoidance of mechanical failures. Abnormal wear in machinery may produce debris exceeding 10 µm. The traditional inductance detection method has low sensitivity and cannot meet the actual detection requirements. To boost the sensitivity of the inductance sensor, the mutual inductance of coils and the strong magnetic conductivity of permalloy was utilized to design a high sensitivity inductance sensor for the detection of debris in lubricating oil. This design was able to detect 10-15 µm iron particles and 65-70 µm copper particles in the oil. The experimental results illustrate that low-frequency excitation is the best for detecting ferromagnetic particles, while high-frequency excitation has the best effect for detecting non-ferromagnetic particles. This paper demonstrates the significant advantages of coil mutual inductance, and strong magnetic conductivity of permalloy in improving the detection sensitivity of oil debris sensors. This will provide technical support for wear detection in mechanical equipment and fault diagnosis.
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Ferro , Magnetismo , Condutividade Elétrica , PermeabilidadeRESUMO
Heme oxygenase 1 (HO-1, encoded by the HMOX1 gene) is the rate-limiting enzyme that catalyzes heme degradation, and it has been reported to exert antioxidative effects. Recently, decidualization has been reported to confer resistance to environmental stress signals, protecting against oxidative stress. However, the effects and regulatory mechanism of HO-1 in decidual stromal cells (DSCs) during early pregnancy remain unknown. Here, we verified that the levels of HO-1 and heme in DSCs are increased compared with those in endometrial stromal cells. Additionally, the upregulation of HIF1A expression led to increased HMOX1 expression in DSCs possibly via nuclear factor erythroid 2-related factor (encoded by the NFE2L2 gene). However, addition of the competitive HO-1 inhibitor zinc protoporphyrin IX resulted in an increase in HIF1A expression. Hydrogen peroxide (H2O2) induced the production of reactive oxygen species (ROS), decreased the cell viability of DSCs in vitro, and upregulated the level of heme. As an HO-1 inducer, cobalt protoporphyrin IX decreased ROS production and significantly reversed the inhibitory effect of H2O2 on cell viability. More importantly, patients with unexplained spontaneous abortion had low levels of HO-1 that were insufficient to protect against oxidative stress. This study suggests that the upregulation of HO-1 expression via HIF1A protects DSCs against excessive heme-mediated oxidative stress. Furthermore, the excessive oxidative stress injury and impaired viability of DSCs associated with decreased HO-1 expression should be associated with the occurrence and/or development of spontaneous abortion.
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Heme Oxigenase-1 , Peróxido de Hidrogênio , Apoptose , Sobrevivência Celular , Heme , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Heme Oxigenase-1/farmacologia , Humanos , Peróxido de Hidrogênio/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/farmacologia , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Células Estromais/metabolismoRESUMO
A successful pregnancy requires sufficient decidualization of endometrial stromal cells (ESCs). CD82, a metastasis suppressor, is a critical regulator for trophoblast invasion but the effect in decidualization was largely unknown. Here we reported that there was a high level of CD82 in DSC by the immunohistochemistry staining and flow cytometer analysis. Stimulation with prostaglandin E2 (PGE2) elevated the expression of CD82 in ESCs. In contrast, celecoxib, a selective COX-2 inhibitor, significantly downregulated the expression of CD82 in decidual stromal cells (DSCs). Bioinformatics analysis and further research showed that recombinant human interleukin (IL)-1ß protein (rhIL-1ß) upregulated CD82 in ESCs. Of note, blocking IL-1ß signaling with anti-human IL-1ß neutralizing antibody could reverse the stimulatory effect of PGE2 on CD82 in ESCs. Silencing CD82 resulted in the decease of the decidualization markers PRL and IGFBP1 mRNA levels in DSCs. More importantly, we observed rhIL-1ß also upregulated the expression of COX-2, and the upregulation of PRL and IGFBP1 induced by rhIL-1ß could be abolished by celecoxib in ESCs or CD82 deficiency in DSCs. This study suggests that CD82 should be a novel promotor for decidualization under a positive regulation of the COX-2/PGE2/IL-1ß positive feedback loop.
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Decídua , Proteína Kangai-1 , Células Estromais , Células Cultivadas , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Decídua/metabolismo , Feminino , Humanos , Interleucina-1beta/metabolismo , Proteína Kangai-1/genética , Proteína Kangai-1/metabolismo , Gravidez , Células Estromais/metabolismo , Trofoblastos/metabolismoRESUMO
BACKGROUND: The effects of grazing on soil methane (CH4) uptake in steppe ecosystems are important for understanding carbon sequestration and cycling because the role of grassland soil for CH4 uptake can have major impacts at the global level. Here, a meta-analysis of 27 individual studies was carried out to assess the response patterns of soil CH4 uptake to grazing in steppe ecosystems of China. The weighted log response ratio was used to assess the effect size. RESULTS: We found that heavy grazing significantly depressed soil CH4 uptake by 36.47%, but light and moderate grazing had no significant effects in grassland ecosystem. The response of grassland soil CH4 uptake to grazing also was found to depend upon grazing intensity, grazing duration and climatic types. The increase in soil temperature and reduced aboveground biomass and soil moisture induced by heavy grazing may be the major regulators of the soil CH4 uptake. CONCLUSIONS: These findings imply that grazing effects on soil CH4 uptake are highly context-specific and that grazing in different grasslands might be managed differently to help mitigate greenhouse gas emissions.
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Comportamento Alimentar , Pradaria , Metano/metabolismo , Ruminantes/fisiologia , Solo/química , Criação de Animais Domésticos , Animais , China , Clima , Estações do AnoRESUMO
Fluoride concentration is a key aspect of water quality and essential for human health. Too much or too little fluoride intake from water supplies is harmful to public health. In this study, a capillary waveguide integrated fiber-optic sensor was fabricated for fluoride measurement in water samples. The sensor was modularly designed with three parts, i.e., a light source, capillary flow cell and detector. When light propagated from a light emitting diode (LED) to the capillary waveguide cell through an excitation fiber, it interacted with the sensing reagent, and its intensity changed with different fluoride concentrations. Then, the light propagated to the detector through a detection fiber for absorption determination of fluoride according to Beer's law. This miniaturized sensor showed advantages of fast analysis (9.2 s) and small reagent demand (200 µL) per sample, and it also had a low detection limit (8 ppb) and high selectivity for fluoride determination. The sensor was applied to fluoride determination in different water samples. The results obtained were compared with those obtained by conventional spectrophotometry and ion chromatography, showing agreement and validating the sensor's potential application.
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A microfluidic-capillary-waveguide-coupled fiber-optic sensor was developed for colorimetric determination of hazardous nitrite based on the Griess-Ilosvay reaction. The sensor was modularly designed by use of a light-emitting diode as the light source, silica fiber as the light transmission element, and a capillary waveguide tube as the light reaction flow cell. With the light interacting with the azo dye generated by the Griess-Ilosvay reaction between nitrite and Griess reagents, nitrite could be determined by a colorimetric method according to Beer's law. By use of the inexpensive and micro-sized elements mentioned above, the sensor provided a new low-cost and portable method for in situ and online measurement of nitrite. The sensor had a wide linear range for nitrite from 0.02 to 1.8 mg L(-1) and a low detection limit of 7 µg L(-1) (3σ), with a relative standard deviation of 0.37% (n = 10). With a low reagent demand of 200 µL, a short response time of 6.24 s, and excellent selectivity, the sensor is environmentally friendly and has been applied to nitrite determination in different water samples. The results were compared with those obtained by conventional spectrophotometry and ion chromatography, indicating the sensor's potential for practical applications.
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Some FeS2 samples among metamorphic belt between coal and intrusion from Wolonghu mine in the north of Anhui Province were retrieved to characterize the signature of Raman Spectral. The results show that, all Raman data of different samples can be divided into 3 types as â , â ¡ and â ¢ according to distinct differences of in Raman mode (M), Raman shift (Δν) and scattering intensity (â ). There are five strong scattering modes including high value Eg (1.16~1.59×103), high value Ag (2.33~2.53×103) and low value Tg (0.20~0.27×103) in typeâ and only former three modes in type â ¡ although the value of Eg, Ag and Tg are similar between them. While there are only two modes of high value Eg about 327.6~328.8 cm-1 and low value Ag 389.0~390.1 cm-1. Our analyses indicate that type â samples must be mixed crystal of pyrite and natural coke for the former three peaks are same to deformation and stretching vibration of Fe-[S2]2- and stretching vibration of SS in pyrite, while the latter two are similar to the vibration of Tiny graphite crystals and stretching vibration of CC among graphite crystal from Raman data. And typeâ ¡sample may be pyrite for typical pyrite Scattering peak and Type â ¢ sample possibility are low-temperature crystalloblastic of pyrite for Marcasite spectrum features in Raman. Further analysis also showed that the formation pressure of typeâ and â ¡ are the same while type â ¢ samples formed in low pressure for Raman scattered intensity of typeâ and â ¡ are similar, and type â ¢ samples is obviously lower than the former two. And the formation temperature of typeâ , typeâ ¡ and type â ¢ significantly decreased in turn for Ag peak of them are turn to high frequency about 4.4~6.7, 4.5~8.4cm-1 respectively compared with the former. Thusï¼The authors' studies suggest that pyrite samples from Metamorphic coal and metamorphic zone in Wolonghu coal mine are products in high temperature, but samples from Magmatic rocks are Marcasite formed at low temperature.
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A Rh(III)-catalyzed [3 + 3]-coupling cyclization of 3-hydroxy-3-phenylisoindolinone with carbenoids has been developed. The method provides an efficient approach to access polyfunctionalized-spiro[isochromene-1,1'-isoindolin]-3'-ones with good to excellent reaction conversions.
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The external bonding (EB) of fiber-reinforced polymer (FRP) is a usual flexural reinforcement method. When using the technique, premature debonding failure still remains a factor of concern. The effect of incorporating multi-wall carbon nanotubes (MWCNTs) in epoxy resin on the flexural behavior of reinforced concrete (RC) beams strengthened with basalt fiber-reinforced polymer (BFRP) sheets was investigated through four-point bending beam tests. Experimental results indicated that the flexural behavior was significantly improved by the MWCNT-modified epoxy. The BFRP sheets bonded by the MWCNT-modified epoxy more effectively mitigated the debonding failure of BFRP sheets and constrained crack development as well as enhanced the ductility and flexural stiffness of strengthened beams. When the beam was reinforced with two-layer BFRP sheets, the yielding load, ultimate load, ultimate deflection, post-yielded flexural stiffness, energy absorption capacity and deflection ductility of beams strengthened using MWCNT-modified epoxy increased by 7.4%, 8.3%, 18.2%, 22.6%, 29.1% and 14.3%, respectively, in comparison to the beam strengthened using pure epoxy. It could be seen in scanning electron microscopy (SEM) images that the MWCNTs could penetrate into concrete and their pull-out and crack bridging consumed more energy, which remarkably enhanced the flexural behavior of the strengthened beams. Finally, an analytical model was proposed for calculating characteristic loads and characteristic deflections of RC beams strengthened with FRP sheets, which indicated a reasonably good correlation with the experimental results.