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Achieving the concurrent manifestation of thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) within a single molecular system is highly sought after for organic light-emitting diodes (OLEDs), yet remains rare. In this study, we present a novel TADF-AIE dye, named PQMO-PXZ, which has been designed, synthesized, and systematically characterized. Our comprehensive investigation, which includes structural analysis, theoretical calculations, and optical studies, evaluates the potential of PQMO-PXZ for integration into OLEDs. Unlike existing azaryl-ketone-based emitters, PQMO-PXZ exhibits red-shifted emission and enhanced luminescence efficiency, due to its rigid structure and strong intramolecular charge transfer characteristics. Significantly, PQMO-PXZ demonstrates pronounced AIE properties and TADF with a short delayed lifetime. When utilized as the emissive core, OLED devices based on PQMO-PXZ achieve a respectable external quantum efficiency of up to 11.8% with minimal efficiency roll-off, underscoring PQMO-PXZ's promise as a highly efficient candidate for OLED applications.
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State-of-the-art smart cities have been calling for economic but efficient energy management over a large-scale network, especially for the electric power system. It is a critical issue to monitor, analyze, and control electric loads of all users in the system. In this study, a non-intrusive load monitoring method was designed for smart power management using computer vision techniques popular in artificial intelligence. First of all, one-dimensional current signals are mapped onto two-dimensional color feature images using signal transforms (including the wavelet transform and discrete Fourier transform) and Gramian Angular Field (GAF) methods. Second, a deep neural network with multi-scale feature extraction and attention mechanism is proposed to recognize all electrical loads from the color feature images. Third, a cloud-based approach was designed for the non-intrusive monitoring of all users, thereby saving energy costs during power system control. Experimental results on both public and private datasets demonstrate that the method achieves superior performances compared to its peers, and thus supports efficient energy management over a large-scale Internet of Things network.
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Background: The benefits of hyperbaric oxygen (HBO) in treating animals with heat stroke (HS) have been established. This study aims to retrospectively analyze the effect of HBO on multiple organ dysfunction following HS in humans. Methods: Retrospective data were collected from patients with HS admitted to our hospital in the past 7 years. Patients were categorized into groups based on whether they received HBO therapy. The study compared various factors, including sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation-â ¡ (APACHE-â ¡) scores, mortality rates, neurological function scores, serum myocardial enzyme levels, liver, kidney, and coagulation function indicators, blood routine results, electrolyte levels, and modified Barthel index (MBI) score for standard daily living ability before treatment and after 2 and 4 weeks of treatment. Results: The mortality rates in the HBO and control group were 0% and 8.49%, respectively. Upon admission, the HBO group had higher SOFA and APACHE-â ¡ scores and lower neurological, coagulation, and liver functions than those of the control group. HBO treatment significantly improved SOFA, APACHE-â ¡, and neurological scores while relieving levels of alanine aminotransferase, aspartate aminotransferase, creatinine, and myocardial enzymes. Additionally, it mitigating lymphocyte and platelet count decline caused by HS. The MBI score was significantly enhanced after treatment in the HBO group. Conclusions: Clinical practice advocates administering HBO therapy to patients with severe illness, organ damage, and nerve impairment. Compared with conventional treatment, combined HBO therapy demonstrated superior efficacy in alleviating multiple organ dysfunction and improving daily living ability in patients with HS.
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Objective: The present study aimed to evaluate the efficacy of a new two-dimensional shear wave elastography (2D-SWE) method using a Siemens ultrasound system and its combination with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) for the differential diagnosis of benign and malignant thyroid nodules. Methods: Conventional ultrasound images and 2D-SWE (E-whole-mean and E-stiffest-mean) were prospectively analyzed in 593 thyroid nodules from 543 patients. Nodules were divided into diameter (D) ≤10 mm and D > 10 mm groups and graded using ACR TI-RADS. The receiver operating characteristic curve was plotted using pathological findings as the gold standard. Diagnostic performance was compared among 2D-SWE, ACR TI-RADS, and their combination. Results: The area under the curve (AUC) for E-whole-mean was higher than that for E-stiffest-mean (0.858 vs. 0.790, P < 0.001), which indicated that it was the better 2D-SWE parameter for differentiating malignant nodules from benign nodules with an optimal cut-off point of 11.36 kPa. In the all-sizes group, the AUC for E-whole-mean was higher than that for ACR TI-RADS (0.858 vs. 0.808, P < 0.001). The combination of E-whole-mean and ACR TI-RADS resulted in a higher AUC (0.929 vs. 0.858 vs. 0.808, P < 0.001), sensitivity (87.0% vs. 80.3% vs. 85.2%), specificity (85.1% vs. 74.0% vs. 73.6%), accuracy (86.3% vs. 78.1% vs. 81.1%), positive predictive value (91.5% vs. 85.1% vs. 85.6%), and negative predictive value (78.0% vs. 67.0% vs. 72.9%) compared to E-whole-mean or ACR TI-RADS alone. The AUC for the combination of 2D-SWE and ACR TI-RADS was superior to that for E-whole-mean or ACR TI-RADS alone in both D ≤ 10 mm and D > 10 mm groups (P < 0.001). Conclusion: As the better 2D-SWE parameter, E-whole-mean had a higher diagnostic power than ACR TI-RADS and enhanced the diagnostic performance of ACR TI-RADS when identifying benign and malignant thyroid nodules. The combination of E-whole-mean and ACR TI-RADS improved the diagnostic performance compared to using ACR TI-RADS alone, providing a new and reliable method for the clinical diagnosis of thyroid nodules.
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Objective: Our aim was to develop dual-modal CNN models based on combining conventional ultrasound (US) images and shear-wave elastography (SWE) of peritumoral region to improve prediction of breast cancer. Method: We retrospectively collected US images and SWE data of 1271 ACR- BIRADS 4 breast lesions from 1116 female patients (mean age ± standard deviation, 45.40 ± 9.65 years). The lesions were divided into three subgroups based on the maximum diameter (MD): ≤15 mm; >15 mm and ≤25 mm; >25 mm. We recorded lesion stiffness (SWV1) and 5-point average stiffness of the peritumoral tissue (SWV5). The CNN models were built based on the segmentation of different widths of peritumoral tissue (0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm) and internal SWE image of the lesions. All single-parameter CNN models, dual-modal CNN models, and quantitative SWE parameters in the training cohort (971 lesions) and the validation cohort (300 lesions) were assessed by receiver operating characteristic (ROC) curve. Results: The US + 1.0 mm SWE model achieved the highest area under the ROC curve (AUC) in the subgroup of lesions with MD ≤15 mm in both the training (0.94) and the validation cohorts (0.91). In the subgroups with MD between15 and 25 mm and above 25 mm, the US + 2.0 mm SWE model achieved the highest AUCs in both the training cohort (0.96 and 0.95, respectively) and the validation cohort (0.93 and 0.91, respectively). Conclusion: The dual-modal CNN models based on the combination of US and peritumoral region SWE images allow accurate prediction of breast cancer.
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Reward signals reflect the developmental tendency of reinforcement learning (RL) agents. Reward-modulated spike-time-dependent plasticity (R-STDP) is an efficient and concise information processing feature in RL. However, the physical construction of R-STDP normally demands complex circuit design engineering, resulting in large power consumption and large area. In this work, we studied the role of ferroelectric polarization in the modulation of carbon nanotube transistor channel polarity. Furthermore, we applied a modulating channel method to construct a 2T synaptic component by spin-coating technology. Based on the nonvolatility of ferroelectric polarization, the synaptic component constructed has the characteristics of reconfigurable polarity. One channel could be modulated to n-type and the other to p-type. One modulated channel was used to perform the STDP function when the reward signal arrived, and the other modulated channel was used to perform the anti-STDP function when the punishment signal arrived. Finally, R-STDP learning rules are implemented on hardware. This work provides a strategy for hardware construction of RL.
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Modelos Neurológicos , Plasticidade Neuronal , Recompensa , Reforço Psicológico , AprendizagemRESUMO
Nonylphenol (NP) is a widely used chemical, which has been considered a kind of endocrine-disrupting chemical and is involved in the occurrence and development of many types of cancers. Our recent studies demonstrated that NP exposure is related to colorectal cancer (CRC) progression. In this study, we also found epithelial-mesenchymal transition (EMT) promoted by NP treatment in CRC cells. However, the mechanism of NP on tumor metastasis is still unclear. In this study, we focused on the effect of the regulator of cell cycle (RGCC) induced by NP treatment. The cancer genome atlas (TCGA) analysis suggested that the expression of RGCC increased in CRC tissues, and our clinical samples showed that the expression of RGCC in tumor tissues is positively correlated with the serum level of NP in CRC patients. Further studies revealed that overexpression of RGCC could enhance the NP-induced EMT process in CRC cells and activate ERK signaling pathways. Inhibiting ERK signaling by ERK inhibitors or the knockdown of RGCC could attenuate the NP-induced EMT process. In addition, both RGCC overexpression and NP treatment could activate ERK pathways and attenuate the effect of ERK inhibitors on the EMT process in CRC cells. Altogether, this study demonstrated that NP could induce cell invasion and migration by increasing the expression of RGCC to enhance the EMT process, which might be through the activation of ERK signaling pathways. This finding supported a potential target for studying NP exposure-related colorectal cancers.
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Neoplasias Colorretais , Transição Epitelial-Mesenquimal , Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células/genética , Neoplasias Colorretais/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Fenóis/farmacologiaRESUMO
Magnesium (Mg) alloys are potential materials for orthopedic fixation devices but rapid degradation of the materials restricts wider clinical applications. Herein, zinc-incorporated calcium phosphate (Ca-Zn-P) coatings are prepared on the Zn-pretreated WE43 Mg alloy by a hydrothermal technique under relatively stable and favorable conditions. The hydrothermal coating consists of a compact bottom layer of CaZn2(PO4)2â2 H2O and ZnO granular crystals and a jagged upper layer of CaHPO4. The Zn coating reduces the corrosion current density of WE43 to (3.49 ± 1.60) × 10-5 A cm-2, whereas the Ca-Zn-P/Zn composite coating further reduces it by 3 orders of magnitude in the simulated body fluid (SBF). The charge transfer resistances of the Zn-coated and Ca-Zn-P/Zn-coated alloys increase by 49 and 7176 times to 835 and 1.22 × 105 Ω cm2, respectively. The 7-day immersion results reveal that the Zn coating cannot provide long-term protection to WE43 in SBF because of the formation of galvanic couples between the Zn coating and WE43. In contrast, Ca-Zn-P/Zn-coated WE43 remains intact after soaking for 7 days and furthermore, the Ca-Zn-P coating self-repairs and continues to grow despite dissolution. The compact and adherent Ca-Zn-P bottom layer plays a major role in mitigating corrosion of WE43 by hindering penetration of the aggressive medium and charge transfer of the corrosion reactions resulting in only slight corrosion of the Zn layer. Biologically, the Zn coating reduces attachment and proliferation of MC3T3-E1 pre-osteoblasts on WE43, but the composite coating fosters cell adhesion and proliferation which stems from the good biocompatibility of the hydrothermal layer and relatively stable surface conditions avoiding severe corrosion.
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Magnésio , Óxido de Zinco , Ligas/química , Ligas/farmacologia , Fosfatos de Cálcio , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Corrosão , Magnésio/química , Magnésio/farmacologia , Teste de Materiais , Zinco/química , Zinco/farmacologiaRESUMO
To study the responses of radial growth of Juniperus przewalskii to climate factors of the different periods (pre-growing season (February-April), growing season (May-July)), and the vulnerability (resistance, RT; recovery, RC) of J. przewalskii to different drought events (precipitation, temperature and the both caused), we used tree ring width data of J. przewalskii from 17 sampling sites across the northeastern Tibetan Plateau to analyze the correlation between radial growth and climate factors of different periods, and the vulnerability in different drought events. The results showed that radial growth of J. przewalskii had significant positive correlation with drought index and negative correlation with temperature in the growing season (P<0.1). The vulnerability of J. przewalskii to drought events of different periods had significant difference. In the pre-growing season drought events, the RT of J. przewalskii at low altitude was 2.3% higher than that at high altitude, the RC of J. przewalskii at low altitude was 25.1% lower than that at high altitude. For drought events in the growing season, the RT of J. przewalskii at low altitude was 23.7% lower than that at high altitude, the RC of J. przewalskii at low altitude was 107.1% higher than that at high altitude. The mean RC(1.68) of J. przewalskii in precipitation-caused drought events was strong, while the mean RT(1.43) of J. przewalskii in temperature-caused drought events was strong. The growth of J. przewalskii, especially for that at low altitude, would be largely limited by drought caused by global warming in the future.
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Juniperus , China , Clima , Mudança Climática , Secas , Tibet , ÁrvoresRESUMO
Aim: Annual T1 stage papillary thyroid carcinoma (PTC) incidence rates continue to rise, yet the optimal treatment for this cancer type remains controversial. Central lymph node metastasis (CLNM) is a critical determinant in the context of treatment decision-making. While several prior studies have evaluated patients with clinica l T1a(cT1a) stage PTC, there have been fewer analyses of clinical T1b(cT1b) disease to date. The present study was thus formulated to explore predictors of CLNM in patients with cT1a and cT1b stage PTC. Methods: A retrospective analysis of data including clinicopathological characteristics and BRAFV600E mutation status was conducted for 452 PTC patients undergoing surgical treatment. Logistic univariate and multivariate analyses were performed to identify risk factors associated with CLNM in particular patients' characteristics and the accuracy of the established logistic regression models was evaluated using the R software platform. Results: Respective CLNM incidence rates in cT1a and cT1b disease were 39.39% and 67.21%. Factors associated with a higher risk of CLNM among PTC(cT1a) patients included male sex, young age, tumor size, contact with capsule, and multifocality as determined through comparisons of the area under the curve for logistic regression models. Whereas male sex and age were associated with CLNM risk in PTC(cT1b) patients in univariate and multivariate analyses, age was the only risk factor associated with CLNM incidence among women with PTC(cT1b). Conclusion: Predictors of CLNM differ between PTC patients with cT1a and cT1b stage disease, and a comprehensive assessment of these risk factors should thus be conducted when designing individualized treatment regimens for PTC patients.
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Carcinoma Papilar , Neoplasias da Glândula Tireoide , Carcinoma Papilar/patologia , Feminino , Humanos , Metástase Linfática , Masculino , Estudos Retrospectivos , Fatores de Risco , Câncer Papilífero da Tireoide/patologia , Câncer Papilífero da Tireoide/cirurgia , Neoplasias da Glândula Tireoide/epidemiologia , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/cirurgiaRESUMO
The aim of the study described here was to assess the evaluation of tissue stiffness around lesions by sound touch shear wave elastography (STE) in breast malignancy diagnosis. This was an institutional ethics committee-approved, single-center study. A total of 90 women with breast masses examined with conventional ultrasound and STE were eligible for enrollment from December 2020 to July 2021. The maximum and mean elastic values of masses, Emax and Emean, were determined. Shell function was used to measure the maximum and mean elastic values of tissues around masses in annular shells 0.5, 1.0, 1.5 and 2.0 mm wide, recorded as corresponding Emax-shell and Emean-shell. All parameters were analyzed and compared with histopathologic results. Receiver operating characteristic curves were constructed to assess diagnostic performance. Logistic regression analysis was conducted to determine the best diagnostic model. Collagen fiber content of tissues around breast lesions was evaluated using Masson staining and ImageJ software. Ninety women with breast masses were included in this study; 50 had benign (mean diameter 15.84 ± 4.39 mm) and 40 had malignant (mean diameter 17.40 ± 5.42 mm) masses. The diagnostic value of Emax-shell-2.0 was the highest (area under the curve = 0.930) with a sensitivity of 87.5% and specificity of 88%. According to stepwise logistic regression analysis, Emax-shell-2.0 and age were independent predictors of malignancy. Emax-shell-2.0 was also found to be highly correlated with the collagen fiber content of tissue in the malignant group (r = 0.877). Tissue stiffness around lesions measured by STE is a useful metric in identifying malignant breast masses by reflecting collagen fiber content, and Emax-shell-2.0 performs best.
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Neoplasias da Mama , Técnicas de Imagem por Elasticidade , Mama/diagnóstico por imagem , Mama/patologia , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Colágeno , Diagnóstico Diferencial , Técnicas de Imagem por Elasticidade/métodos , Feminino , Humanos , Sensibilidade e Especificidade , Ultrassonografia Mamária/métodosRESUMO
Axillary lymph node schistosomiasis is a form of ectopic schistosomiasis, in which the Schistosoma adult worms or eggs are infected in the axillary lymph nodes. A 53-year-old woman visited our hospital with a small mass in the right armpit, which had been present for over 1 month. Histological examination of biopsy samples from the right axillary lymph nodes revealed granulomas containing calcified Schistosoma eggs. This is the first authentic case of ectopic schistosomiasis identified in the axillary lymph nodes.
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Neoplasias da Mama , Esquistossomose , Humanos , Feminino , Axila , Linfonodos , Esquistossomose/diagnóstico , Neoplasias da Mama/patologiaRESUMO
Recently, the effect of endocrine-disrupting chemicals on the cancer procession has been a concern. Nonylphenol (NP) is a common environmental estrogen that has been shown to enhance the proliferation of colorectal cancer (CRC) cells in our previous studies; however, the underlying mechanism remains unclear. In this study, we confirmed the increased concentration of NP in the serum of patients with CRC. RNA sequencing was used to explore the differentially expressed genes after NP exposure. We found 16 upregulated genes and 12 downregulated genes in COLO205 cells after NP treatment. Among these differentially expressed genes, we found that coiled-coil domain containing 80 (CCDC80) was downregulated by NP treatment and was associated with CRC progression. Further experiments revealed that the overexpression of CCDC80 significantly suppressed NP-induced cell proliferation and recovered the reduced cell apoptosis. Meanwhile, the overexpression of CCDC80 significantly inhibited the activation of ERK1/2 induced by NP treatment. ERK1/2 inhibitor (PD98059) treatment also suppressed NP-induced CRC cell growth, but the overexpression of CCDC80 did not enhance the effect of ERK1/2 inhibitor. Taken together, NP treatment significantly inhibited the expression of CCDC80, and the overexpression of CCDC80 suppressed NP-induced CRC cell growth by inhibiting the activation of ERK1/2. These results suggest that NP could induce CRC cell growth by influencing the expression of multiple genes. CCDC80 and ERK1/2 inhibitors may be suitable therapeutic targets in NP-related CRC progression.
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The species-habitat association analysis facilitates a better understanding of species coexis-tence and community assembly. Here, all trees in a 25-hm2 broadleaved deciduous forest plot in the Qinling Mountains of North-central China were classified into three life stages (i.e., seedling, sapling, and adult). The Torus-translation test was used to examine the species-habitat association. The results showed that the association of species with habitats varied across different species. Most species were significantly associated with high slopes, 95.7% of which showed negative association. 89.5% and 90.9% of tree species were negatively associated with low slopes and ridges, respectively. Most species had positive association with high valley, with only one negative association (0.03%). There were 80, 44 and 23 significant associations with habitats at seedling, sapling and adult stages, respectively, indicating that a greater dependence of seedlings on habitat. 38 species at seedling stage and 25 species at the sapling stage were associated with at least one habitat type, while only 17 species at the adult stage were significantly associated. The effects of habitat on species varied across life stages, showing a weaker species-habitat association at the later stage. Due to the specific environmental demands, most species showed different habitat preferences across life stages.
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Ecossistema , Florestas , China , Plântula , ÁrvoresRESUMO
Biocontrol of root-knot nematode has attracted increasing attention over the past two decades. The inconsistent field performance of biocontrol agents, which is caused by soil fungistasis, often restricts their commercial application. There is still a lack of research on the genes involved in biocontrol fungi response to soil fungistasis, which is important for optimizing practical applications of biocontrol fungi. In this study, the lactoylglutathione lyase-encoding AOL_s00004g335 in the nematophagous fungi Arthrobotrys oligospora was knocked out, and three mutant strains were obtained. The hyphal growth of mutants on the three media was almost the same as that of the wild-type strain, but mutants had slightly higher resistance to NaCl, SDS, and H2O2. Methylglyoxal (MG) significantly increased the resistance of A. oligospora to ammonia, but decreased the resistance to benzaldehyde. Furthermore, the resistance of the mutants to soil fungistasis was largely weakened and MG could not increase the resistance of A. oligospora to soil fungistasis. Our results revealed that MG has different effects on the fungistatic roles of ammonia and benzaldehyde and that lactoylglutathione lyase is very important for A. oligospora to resist soil fungistasis.
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Lactoilglutationa Liase , Nematoides , Amônia , Animais , Ascomicetos , Benzaldeídos , Peróxido de Hidrogênio , Aldeído Pirúvico , SoloRESUMO
Tumor-associated macrophages contribute to cell growth, development, and metastasis in various cancers. However, the underlying mechanisms of M2 macrophage that modulate the progression of gastric cancer (GC) remain largely unknown. In this study, we detected the ratio of macrophages in GC tissues and found that the proportion of M2 macrophages was increased in GC tissues. We then co-cultured GC cells with M1 and M2 macrophages, respectively, and then assessed cell proliferation and tumorigenicity of GC cells by MTT and colony formation assay. The results indicated that M2 macrophages promoted the proliferation of GC cells, but M1 not. Besides, GW4869, an exosomes inhibitor, reduced the effects induced by M2 macrophage. Then, we isolated and identified exosomes derived from M1 and M2 macrophage, and confirmed that the exosomes could be taken up by GC cells. We demonstrated that M2 macrophage-exosomes could induce the proliferation and tumorigenesis in vitro and in vivo. Moreover, miR-487a was enriched in M2 macrophage-exosomes and further determined that miR-487a exert the functions by targeting TIA1. In conclusion, exosomal miR-487a derived from M2 macrophage promotes the proliferation and tumorigenesis in gastric cancer, and the novel findings might be helpful to the development of novel diagnostic and therapeutic methods in GC.
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Progressão da Doença , Exossomos/metabolismo , Macrófagos/metabolismo , MicroRNAs/biossíntese , Neoplasias Gástricas/metabolismo , Animais , Proliferação de Células/fisiologia , Técnicas de Cocultura , Exossomos/genética , Exossomos/patologia , Humanos , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologiaRESUMO
OBJECTIVES: To evaluate the surrounding tissue stiffness measured by sound touch elastography for differential diagnosis of thyroid nodules (TNs). METHODS: Thirty-nine benign and 90 malignant TNs were included in this study. The conventional ultrasound features, the maximum Young modulus value of the stiffness of the TNs (recorded as E), and the stiffness of the 0.5-, 1.0-, 1.5-, and 2.0-mm perinodular regions of the TNs (recorded as Eshell0.5 , Eshell1.0 , Eshell1.5 , and Eshell2.0 , respectively) were prospectively analyzed and compared to histopathologic results. The abundance of collagen fibers at various widths in the perinodular regions of the TNs was evaluated by Masson staining and ImageJ software (National Institutes of Health, Bethesda, MD). The fibrous structures in the perinodular regions of the TNs were classified. RESULTS: The various Eshell values of malignant TNs were significantly higher than those of benign TNs (P < .001 for all). Eshell0.5 correlated highly with E in the malignant TNs and in all samples (r = 0.722 and 0.772; P < .001 for both). Eshell2 yielded the highest area under the receiving operating characteristic curve value (0.96) for the differential diagnosis of TNs. The abundance of collagen fibers in the 2-mm perinodular region of the TNs was closely correlated with Eshell2 in the malignant TNs and in all samples (r =0.729 and 0.867; P < .001). The Eshell2 values for different levels of disorder of the tissue surrounding TNs were significantly different (P < .01 for all). CONCLUSIONS: Perinodular stiffness measured by sound touch elastography improved the diagnostic accuracy in TNs.
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Técnicas de Imagem por Elasticidade , Nódulo da Glândula Tireoide , Diagnóstico Diferencial , Módulo de Elasticidade , Humanos , Sensibilidade e Especificidade , Nódulo da Glândula Tireoide/diagnóstico por imagem , UltrassonografiaRESUMO
Soil enzymes play critical roles in material cycle and energy flow of ecosystems. Understanding soil enzyme activities is of great significance for exploring ecosystem functions. In this study, we investigated soil enzyme activities, stoichiometry and their driving factors at six different altitudes (4300-5100 m) on Qinghai-Tibet Plateau alpine meadow using Biolog microplate analysis. The results showed that ß-1,4-glucosidase (ßG) closely related to C cycle, ß-1,4-N-acetylglucosaminidase (NAG) and L-leucine aminopeptidase (LAP) closely related to N cycle and the activity of acid phosphatase (AP), which was closely related to P cycle, all exhibited unimodal trends with increasing altitude, with the order of 4800 mï¼4950 mï¼4400 mï¼4650 mï¼5100 mï¼4300 m. Soil N:P enzyme activity ratio showed the same trend as soil enzyme activity, and reached the highest value at 4950 m, however, soil C:N and C:P enzyme activities ratios increased along the altitude. Pearson correlation analysis showed that SOC, TN and soil water content were significantly positively correlated with the activities of four types of enzymes. Mean annual precipitation was significantly negatively associated with the activities of NAG and AP. Mean annual precipitation, mean annual temperature, Shannon diversity, vegetation richness, vegetation coverage and TN affected ratios of soil C:P and N:P enzymes. Soil C:N activity ratio correlated with mean annual temperature, mean annual precipitation, vegetation richness, vegetation coverage, SOC and TN. In summary, soil enzyme activities and stoichiometry had remarkable difference along the altitude gradient on Qinghai-Tibet Plateau alpine meadow, with certain N limitation in high altitude areas. Soil water content, TN, SOC, mean annual precipitation and mean annual temperature were key factors driving such differences.
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Altitude , Solo , China , Ecossistema , Pradaria , TibetRESUMO
Soil microbial community structure and functional diversity have great implications for the maintenance of the function and stability of grassland ecosystem. We studied the variation of soil microbial community structure, community diversity of carbon metabolism and their driving factors between the long-term enclosure and the free grazing grasslands in Qinghai-Tibet Plateau by using phospholipid fatty acid and Biolog techniques. The results showed that: 1) there were significant differences in soil microbial community structure and the utilization of carbon source between the long-term enclosed and free grazed grasslands. 2) Long-term enclosure significantly increased the content of total PLFA, bacteria, fungi and actinomycetes. 3) Soil carbon metabolic activity, diversity and richness in free-grazing grassland was significantly higher than the enclosed grassland, but evenness showed an opposite pattern. 4) Compared with the free grazed grassland, long-term enclosure significantly increased the utilization of polymers, carbohydrates, carboxylic acids, and amines by soil microorganisms. 5) Results from the redundancy analysis showed that vegetation coverage significantly affected soil microbial community structure and carbon metabolism. The soil microbial content, carbon metabolism diversity and richness in the long-term enclosed grassland were higher than those of the free grazing grassland, indicating that long-term enclosure was more conducive to improve the diversity and carbon metabolism of soil microbial community.
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Pradaria , Microbiologia do Solo , Bactérias , Carbono , Ecossistema , Ácidos Graxos , Fungos , Fosfolipídeos , Solo , TibetRESUMO
At the Jiapigou gold mine of the Songhua River upstream, reed leaves (Phragmites australis), soil, and water samples were collected from June (summer) and September (autumn) 2016 for the determination of mercury. Moreover, the mercury concentrations in the air were determined synchronously. Furthermore, the level of mercury pollution in the reed leaves was determined by a single factor pollution index method, and the relationships among mercury concentrations in the reed leaves and environmental factors were analyzed to research the distribution characteristics, influencing factors, and correlations around the gold mining area. The results show that, in terms of spatial distribution, the mercury concentrations in reed leaves, soil, and water gradually decay with the distance from the gold mining area, and the spatial distribution of the mercury concentrations in the air was not obvious. Regarding a temporal distribution, the mercury concentrations in the reed leaves in summer were lower than those in autumn in the heavy pollution areas, while the distribution in the light pollution areas was the opposite, as the mercury concentrations of air and soil in summer were higher than those in autumn. The influence of environmental factors on the mercury concentrations in the reed leaves was soil > air > water. In addition, after stopping gold mining and processing using mercury, the mercury source in the area was the soil.