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1.
Cell Biol Int ; 46(3): 336-343, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34941001

RESUMO

Osteosarcoma is a malignant tumor that often occurs in adolescents. There is an urgent need for new treatment options for osteosarcoma due to its poor prognosis after metastasis. Cancer stem cell (CSC) theory states that CSCs represent a small proportion of cancer cells. These CSC have self-renewal ability and are closely associated with cancer growth and metastasis as well as chemotherapy resistance. Similarly, osteosarcoma stem cells (OSCs) play an important role in the growth, metastasis, and chemotherapy resistance of osteosarcoma cells. Targeting OSCs may represent a future treatment of osteosarcoma. Furthermore, some genes have been shown to regulate the growth, metastasis, and chemotherapy resistance of osteosarcoma cells by altering the stemness of OSCs. Targeting these genes may help in the treatment of osteosarcoma. This review mainly discusses recent advances in the research of OSCs and their related genes.


Assuntos
Neoplasias Ósseas , Osteossarcoma , Adolescente , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Células-Tronco Neoplásicas/patologia , Osteossarcoma/patologia
2.
Front Bioeng Biotechnol ; 10: 912133, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35573242

RESUMO

Non-traumatic osteonecrosis of the femoral head (NONFH) remains a common refractory disease with poorly understood pathogenesis. Macrophage M1/M2 imbalance and chronic inflammatory microenvironment have been suggested to be closely related to osteonecrosis. Here we describe direct visual evidence for the involvement of dynamic changes in macrophages and the chronic inflammatory microenvironment in human NONFH. Osteonecrosis induces inflammatory responses and macrophage enrichment in the reparative area, and the number of inflammatory cells and macrophages falls during progressive-to end-stage NONFH. Multiplex immunohistochemistry demonstrated that macrophage M1/M2 ratio increased from 3 to 10 during progressive-to end-stage. During the progressive-stage, new blood vessels formed in the reparative area, M2 macrophages accumulated in perivascular (M1/M2 ratio ∼0.05), while M1 macrophages were enriched in avascular areas (M1/M2 ratio ∼12). Furthermore, inflammatory cytokines were detected in synovial fluid and plasma using cytometric bead arrays. Interleukin (IL)-6 and IL-1ß were persistently enriched in synovial fluid compared to plasma in patients with NONFH, and this difference was confirmed by immunohistochemistry staining. However, only IL-6 levels in plasma were higher in patients with progressive-stage NONFH than in osteoarthritis. Moreover, fibrosis tissues were observed in the necrotic area in progressive-stage and end-stage NONFH based on Sirius Red staining. Together, these findings indicate that macrophage M1/M2 imbalance facilitates the progression of NONFH, a chronic inflammatory disease characterized by chronic inflammation, osteonecrosis and tissue fibrosis in the local lesion. Inhibiting inflammation, promoting the resolution of inflammation, switching macrophages to an M2 phenotype, or inhibiting their adoption of an M1 phenotype may be useful therapeutic strategies against NONFH.

3.
Artigo em Inglês | MEDLINE | ID: mdl-35427416

RESUMO

The treatment of intervertebral disc degeneration (IVDD) is still a huge challenge for clinical updated surgical techniques and basic strategies of intervertebral disc regeneration. Few studies have ever tried to combine surgery and cell therapy to bridge the gap between clinical and basic research. A prospective clinical study with a 72-month follow-up was conducted to assess the safety and feasibility of autologous discogenic cells transplantation combined with discectomy in the treatment of lumbar disc herniation (LDH) and to evaluate the regenerative ability of discogenic cells in IVDD. Forty patients with LDH who were scheduled to have discectomy enrolled in our study and were divided into the observed group (transplantation of autologous discogenic cells after discectomy) and control group (only-discectomy). Serial MRI and X-ray were used to evaluate the degenerative extent of index discs, and clinical scores were used to determine the symptomatic improvement. No adverse events were observed in the observed group, and seven patients in the control group underwent revisions. Both groups had significant improvement of all functional scores post-operatively, with the observed group improving more considerably at 36-month and 72-month follow-up. The height and water content of discs in both groups decreased significantly since 36 months post-op with the control group decreased more obviously. Discectomy combined with autologous discogenic cells transplantation is safe and feasible in the treatment of LDH. Radiological analysis demonstrated that discogenic cells transplantation could slow down the further degeneration of index discs and decrease the complications of discectomy.

4.
Curr Biol ; 32(8): 1869-1874.e4, 2022 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-35278348

RESUMO

Predator-prey interactions are ubiquitous and powerful forces that structure ecological communities.1-3 Habitat complexity has been shown to be particularly important in regulating the strength of predator-prey interactions.4-6 While it is well established that changes in habitat structure can alter the efficacy of predatory and anti-predatory behaviors,7-9 little is known about the consequences of engineering activity by prey species who modify the external environment to reduce their own predation risk. Using field surveys and manipulative experiments, we evaluated how habitat modification by Brandt's voles (Lasiopodomys brandtii) influences predation risk from a principal avian predator (shrike; Lanius spp.) in a steppe grassland, located in Inner Mongolia, China. We found that voles actively modify habitat structure by cutting down a large, unpalatable bunchgrass species (Achnatherum splendens) in the presence of shrikes, a behavior that disappeared when these avian predators were excluded experimentally. The damage activities of these voless dramatically decreased the volume of unpalatable grasses, which in turn reduced visitations by shrikes and thus mortality rates. Our study shows that herbivorous prey that act as ecosystem engineers can directly reduce their own predation risk by modifying habitat structure. Given the ubiquity of predation risks faced by consumers, and the likely ability of many consumers to alter the habitat structure in which they live, the interplay between predation risk and ecosystem engineering may be an important but unappreciated mechanism at play in natural communities.


Assuntos
Ecossistema , Comportamento Predatório , Animais , Aves , Cadeia Alimentar , Herbivoria , Poaceae , Comportamento Predatório/fisiologia , Roedores
5.
Food Funct ; 13(5): 2832-2845, 2022 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-35179169

RESUMO

Obesity continues to be a global public health challenge. Litchi chinensis seed is rich in bioactive ingredients with pharmacological effects, such as hypoglycemic activity and anti-oxidation. This study aimed to assess the potential anti-obesity effects of L. chinensis seed and the changes of gut microbiota and mycobiota compositions in obese zebrafish induced by a high-fat diet. The anti-obesity effects were supplemented and validated in high-fat diet-induced obese mice. In this study, various chemical components of L. chinensis seed water and ethanol extracts were detected using UHPLC-QE-MS, and both extracts showed strong in vitro antioxidant activities. Network pharmacology analysis showed the potential of the extracts to improve obesity. Litchi chinensis seed powder, water and ethanol extracts decreased the weight of obese zebrafish, improved lipid accumulation and lipid metabolism, regulated appetite, and inhibited cell apoptosis and inflammation of the liver and intestine. They showed similar effects in obese mice, and also reduced the weight of fat tissues, regulated insulin resistance and glucose metabolism, and improved the intestinal barrier. Additionally, L. chinensis seed modulated the compositions of gut microbiota and mycobiota in zebrafish, with the regulation of the proportion of bacteria that produce short-chain fatty acids or affect intestine health, including Cetobacterium, Trichococcus, Aeromonas, Staphylococcus, and Micrococcaceae, and the proportion of fungi that produce mycotoxins or have special metabolic capacities, including Penicillium, Candida, Rhodotorula, and Trichoderma. Spearman's correlation analysis revealed the potential link between zebrafish obesity parameters, gut bacteria and fungi. Overall, these findings indicated that L. chinensis seed effectively improved obesity.


Assuntos
Fármacos Antiobesidade/farmacologia , Antioxidantes/farmacologia , Litchi , Extratos Vegetais/farmacologia , Animais , Fármacos Antiobesidade/química , Antioxidantes/química , Dieta Hiperlipídica , Modelos Animais de Doenças , Microbioma Gastrointestinal/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/prevenção & controle , Extratos Vegetais/química , Sementes , Peixe-Zebra
6.
ACS Appl Mater Interfaces ; 14(9): 11350-11358, 2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35199988

RESUMO

The electrochemical oxygen reduction reaction (ORR) offers a promising method to replace the anthraquinone process for hydrogen peroxide (H2O2) production. However, the efficiency of this process suffers from sluggish kinetics, particularly in an acidic environment. Therefore, employing catalysts with high electroactivity is highly desirable for H2O2 synthesis. Here, an effective strategy for preparing Co-N-C/Ti3C2Tx with high H2O2 selectivity and ORR reactivity is proposed. The acquired Co-N-C/Ti3C2Tx shows excellent H2O2 electrosynthesis performance in acidic media with H2O2 productivity of up to 3200 ppm h-1, superior to state-of-the-art catalysts. Interestingly, a H2O2 concentration of 6.0 wt % was obtained after the stability test, and the Co-N-C/Ti3C2Tx catalyst was found to effectively catalyze organic dye degradation. Further analysis reveals that the enhanced H2O2 electrosynthesis performance originates from the layered structure and the oxygen functional groups of Ti3C2Tx. The layered structure can effectively promote increased exposure of active sites, while the oxygen functional groups will fine-tune the electronic structure of Co atoms, allowing a selective ORR pathway to produce H2O2. This work provides a strategy to design and fabricate highly efficient catalysts for H2O2 production and degradation of organic pollutants.

7.
ACS Appl Mater Interfaces ; 14(6): 7592-7608, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35119809

RESUMO

Natural polysaccharide (NPH)-based injectable hydrogels have shown great potential for critical-sized bone defect repair. However, their osteogenic, angiogenic, and mechanical properties are insufficient. Here, MgO nanoparticles (NPs) were incorporated into a newly synthesized water-soluble phosphocreatine-functionalized chitosan (CSMP) water solution to form an injectable hydrogel (CSMP-MgO) via supramolecular combination between phosphate groups in CSMP and magnesium in MgO NPs to circumvent these drawbacks of chitosan-based injectable hydrogels. Water-soluble chitosan deviate CSMP was first synthesized by grafting methacrylic anhydride and phosphocreatine into a chitosan chain in a one-step lyophilization process. The phosphocreatine in this hydrogel not only provides sites to combine with MgO NPs to form supramolecular binding but also serves as the reservoir to control Mg2+ release. As a result, the lyophilized CSMP-MgO hydrogels presented a porous structure with some small holes in the pore wall, and the pore diameters ranged from 50 to 100 µm. The CSMP-MgO injectable hydrogels were restricted from swelling in DI water (lowest swelling ratio was 16.0 ± 1.1 g/g) and presented no brittle failure during compression even at a strain above 85% (maximum compressive strength was 195.0 kPa) versus the control groups (28.0 and 41.3 kPa for CSMP and CSMP-MgO (0.5) hydrogels), with regulated Mg2+ release in a stable and sustained manner. The CSMP-MgO injectable hydrogels promoted in vitro calcium phosphate (hydroxyapatite (HA) and tetracalcium phosphate (TTCP)) deposition in supersaturated calcium phosphate solution and presented no cytotoxicity to MC3T3-E1 cells; the CSMP-MgO hydrogel promoted MC3T3-E1 cell osteogenic differentiation with upregulation of BSP, OPN, and Osterix osteogenic gene expression and mineralization and HUVEC tube formation. Among them, CSMP-MgO (5) presented most of these properties. Moreover, this hydrogel (CSMP-MgO (5)) showed an excellent ability to promote new bone formation in critical-sized calvarial defects in rats. Thus, the CSMP-MgO injectable hydrogel shows great promise for bone regeneration.


Assuntos
Quitosana , Nanopartículas , Animais , Regeneração Óssea , Quitosana/química , Quitosana/farmacologia , Durapatita/química , Hidrogéis/química , Hidrogéis/farmacologia , Óxido de Magnésio/farmacologia , Nanopartículas/química , Osteogênese , Óxidos , Ratos
8.
Ecology ; 103(4): e3635, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35060616

RESUMO

While large herbivores are critically important components of terrestrial ecosystems and can have pronounced top-down effects on plants, our understanding of the underlying mechanisms driving these effects remains incomplete. Large herbivores can alter plant growth, reproduction, and abundance through direct effects (predominantly consumption) and through indirect effects via altered interactions with abiotic factors and other species. We know considerably less about these indirect effects than the direct effects. Here, we integrate medium- and small-scale field experiments to investigate how a large vertebrate herbivore, cattle (Bos taurus), affects the aboveground biomass of a dominant forb species, Artemisia scoparia, via diverse direct and indirect pathways in a temperate grassland in northeast China. Although cattle consumed this forb, its biomass increased significantly in response to grazing, due to multiple indirect positive effects that outweighed the direct negative effects of consumption. Cattle preferentially consumed the competing grass Leymus chinensis, and altered Artemisia microhabitats by reducing total plant cover and litter biomass and by increasing the abundance of co-occurring ant species (e.g., Formica spp. and Lasius spp.). This led to additional indirect positive effects on A. scoparia likely due to (1) increased light availability in understory layers and other limiting resources (e.g., soil nutrients and moisture) caused by removal of competitors and plant litter at the soil surface and (2) the changes in resource availability (e.g., soil nutrients and moisture) associated with ant colonies. Our results show that large herbivores can affect plant growth not only via direct consumption, but also via multiple indirect effects. Focusing on the causes and consequences of herbivore-induced indirect effects will not only help us to better understand the influence of these animals in ecological systems, but will also lead to more effective land management and conservation practices in the regions they inhabit.


Assuntos
Pradaria , Herbivoria , Animais , Biomassa , Bovinos , Ecossistema , Herbivoria/fisiologia , Poaceae , Solo
9.
Cancer Chemother Pharmacol ; 89(1): 31-40, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655298

RESUMO

BACKGROUND: Osteosarcoma is a prevalent type of bone tumor in children and adolescents, with limited treatment and poor prognosis. Abemaciclib, an inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), is approved for the treatment of advanced breast cancer as single agent therapy and is currently under investigation in clinical trials for the treatment of several solid tumors. METHODS: The efficacy of abemaciclib was determined using osteosarcoma cellular assays and xenograft mouse model. The combination studies were performed based on the Chou-Talalay method. Immunoblotting analysis was performed to determine the underlying mechanisms of abemaciclib in osteosarcoma cell lines. RESULTS: Abemaciclib potently inhibits growth, anchorage-independent colony formation and survival of a panel of osteosarcoma cell lines, with IC50 range from 90 nM to >20 µM. In addition, the combination of abemaciclib and doxorubicin is synergistic and antagonistic in abemaciclib-sensitive (IC50 <1 µM) and abemaciclib-resistant (IC50 >1 µM), respectively. Abemaciclib inhibits tumor formation and growth in a dose-dependent manner without causing significant drug toxicity in mice. The combination of abemaciclib and doxorubicin results in much greater efficacy than doxorubicin alone in inhibiting tumor growth throughout the whole treatment duration. Abemaciclib acts on osteosarcoma via suppressing CDK4/6-Cyclin D-Rb pathway. CONCLUSIONS: Our pre-clinical evidence provides a rationale of initializing clinical trial of investigating the efficacy of abemaciclib in combination with doxorubicin in osteosarcoma patients. Our work also highlights the therapeutic value of CDK4/6 inhibition in osteosarcoma with proper function of Rb.


Assuntos
Aminopiridinas/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Benzimidazóis/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Osteossarcoma/tratamento farmacológico , Aminopiridinas/administração & dosagem , Animais , Benzimidazóis/administração & dosagem , Neoplasias Ósseas/genética , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ciclina D/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Doxorrubicina/administração & dosagem , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Redes e Vias Metabólicas/efeitos dos fármacos , Camundongos SCID , Osteossarcoma/genética , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Proteína do Retinoblastoma/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Sci Total Environ ; 811: 151400, 2022 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-34742802

RESUMO

In grasslands, roots of different plant species decay in combination in the presence of living plants, besides, most root decomposition studies are conducted on how roots of plants decomposed alone or in artificial compositions in the absence of living plants. Therefore, we evaluated how roots of different perennial plants induced effects on decomposition process under living plants and their associated mechanisms. By using litter bag technique, we determined the root decomposition process of three perennial plants, Leymus chinensis, Phragmites australis, and Kalimeris integrifolia grown in monocultures, bi- and tri-species mixtures, after 12 months of incubation under living plants and bare soil communities. We found both additive and non-additive effects on decomposition dynamics indicating that root mass losses of compositions cannot be calculated from decaying rates of individual species. The rich-nutrient roots of K. integrifolia in monocultures and in mixtures with other plant species decayed faster. Compared with bare soil, microbial activities were enhanced under living plant communities and hence stimulated decomposition rates. Our results indicated that microbial activities are important but secondary factors to root physico-chemical properties impacting root decomposition rates. In conclusion, the empirical relationships developed here are helpful to better understand the effects of root properties and microbial activities on decay rates.


Assuntos
Ecossistema , Pradaria , Folhas de Planta , Plantas , Poaceae , Solo
11.
Ther Innov Regul Sci ; 56(3): 501-516, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35320578

RESUMO

BACKGROUND: Removal of the extracellular Aß plaques in the brain is one of the mechanisms to treat Alzheimer's disease (AD). Separate clinical trials for several therapeutic compounds that target amyloid plaque reduction have shown noteworthy correlations among plaque removal, the Amyloid-Related Imaging Abnormalities (ARIA) rate, and clinical efficacy of the treatment. The relationships among therapeutic dose levels, the rate of amyloid removal, and the clinical efficacy deserve further investigation across therapeutic agents, particularly for clinical trials to provide insights for strategies to develop amyloid therapies in Alzheimer's disease. METHODS: Published data summaries from clinical trials with amyloid therapies of aducanumab, donanemab, lecanemab, and gantenerumab are evaluated with meta-analyses. Linear mixed models for repeated measurements for visits and random study effects are applied to analyze amyloid centiloid value reduction from baseline and clinical cognition change from baseline for treatment groups according to doses and compounds for the clinical trials. Logistic regression analysis is applied to evaluate the relationship between the amyloid removal rate and the ARIA-Edema (ARIA-E) rate across different dose groups and clinical trials. RESULTS: The extent of amyloid removal varies among therapeutic agents and their dose levels. Across treatment groups and clinical trials, amyloid centiloid value reductions at Weeks 26 and 52 are strongly correlated with both ARIA-E rate over 78 weeks and the clinical efficacy response in the Clinical Dementia-Rating Scale Sum of Boxes (CDR-SB) score change from baseline at Week 78; and the Spearman rank correlations for amyloid reduction at Week 52 are stronger as - 0.79 with the ARIA-E rate over 78 weeks and 0.73 with the Week 78 CDR-SB score change from baseline. CONCLUSION: Aß plaques removal in the brain due to amyloid therapy is strongly correlated with a better clinical response in patients with early Alzheimer's disease and a higher ARIA-E rate for the treatment groups and clinical trials in this meta-analysis. These relationships suggest that the balance between the clinical efficacy response and safety in ARIA-E rate is relevant for the choice of doses for amyloid therapies in confirmatory clinical trials.


Assuntos
Doença de Alzheimer , Doença de Alzheimer/tratamento farmacológico , Anticorpos Monoclonais/uso terapêutico , Encéfalo , Cognição , Humanos , Resultado do Tratamento
12.
Small Methods ; 5(11): e2100937, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34927969

RESUMO

Carbon encapsulation is an effective strategy for enhancing the durability of Pt-based electrocatalysts for the oxygen reduction reaction (ORR). However, high-temperature treatment is not only energy-intensive but also unavoidably leads to possible aggregation. Herein, a low-temperature polymeric carbon encapsulation strategy (≈150 °C) is reported to encase Pt nanoparticles in thin and amorphous carbonaceous layers. Benefiting from the physical confinement effect and enhanced antioxidant property induced by the surface carbon species, significantly improved stabilities can be achieved for polymeric carbon species encapsulated Pt nanoparticles (Pt@C/C). Particularly, a better antipoisoning capability toward CO, SOx , and POx is observed in the case of Pt@C/C. To minimize the thickness of the catalyst layer and reduce the mass transfer resistance, the high mass loading Pt@C/C (40 wt%) is prepared and applied to high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). At 160 °C, a peak power density of 662 mW cm-2 is achieved with 40% Pt@C/C cathode in H2 -O2 HT-PEMFCs, which is superior to that with 40% Pt/C cathode. The facile strategy provides guidance for the synthesis of highly durable carbon encapsulated noble metal electrocatalysts toward ORR.

13.
Ecol Evol ; 11(22): 16314-16326, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34824829

RESUMO

Large herbivores often co-occur and share plant resources with herbivorous insects in grassland ecosystems; yet, how they interact with each other remains poorly understood. We conducted a series of field experiments to investigate whether and how large domestic herbivores (sheep; Ovis aries) may affect the abundance of a common herbivorous insect (aphid; Hyalopterus pruni) in a temperate grassland of northeast China. Our exclosure experiment showed that 3 years (2010-2012) of sheep grazing had led to 86% higher aphid abundance compared with ungrazed sites. Mechanistically, this facilitative effect was driven by grazing altering the plant community, rather than by changes in food availability and predator abundance for aphids. Sheep significantly altered plant community by reducing the abundance of unpalatable forbs for the aphids. Our small-scale forb removal experiment revealed an "associational plant defense" by forbs which protect the grass Phragmites australis from being attacked by the aphids. However, selective grazing on forbs by sheep indirectly disrupted such associational plant defense, making P. australis more susceptible to aphids, consequentially increasing the density of aphids. These findings provide a novel mechanistic explanation for the effects of large herbivores on herbivorous insects by linking selective grazing to plant community composition and the responses of insect populations in grassland ecosystems.

14.
Toxics ; 9(11)2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34822700

RESUMO

The mercury that is released from the centralized treatment of municipal solid waste is an important source of atmospheric mercury. We chose the main urban area of Changchun as a representative area. Environmental factors such as total mercury content, temperature, wind speed, and other factors were measured in samples from the trash cans of two types of collection points (trash cans and garbage stations), the topsoil under the selected trash cans, and the ambient air above the selected trash cans. The potential ecological risks of mercury pollution were evaluated. The results showed that the mercury content levels of all sample types in the refuse transfer station were higher than the garbage cans and there were no significant differences observed between soil surface mercury and garbage cans. The mercury content levels in the atmosphere and the surface soil at the garbage collection points were found to increase along the cascade relationship of the garbage collection. However, there were no correlations observed between the atmospheric mercury content levels and the surface soil mercury content levels with the attachments and the sum of the former two. There were no correlations observed between surface soil and the attachments, or among the attachments, surface soil, and the atmospheric mercury content levels. The mercury content levels in the attachments, surface soil, and atmosphere of the garbage collection points in the study area were negatively correlated with the loop lines. Meanwhile, the potential ecological risk indexes of the garbage cans and garbage stations were found to be high. The chronic non-carcinogenic risks of mercury to children and adults were determined to be very low. The risks of mercury to children were higher when compared with adults. The highest non-carcinogenic risks of mercury pollution were determined to be within the central area of Changchun.

15.
Materials (Basel) ; 14(21)2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34772118

RESUMO

The traditional mathematical model of shape memory alloy (SMA) is complicated and difficult to program in numerical analysis. The artificial neural network is a nonlinear modeling method which does not depend on the mathematical model and avoids the inevitable error in the traditional modeling method. In this paper, an optimized neural network prediction model of shape memory alloy and its application for structural vibration control are discussed. The superelastic properties of austenitic SMA wires were tested by experiments. The material property test data were taken as the training samples of the BP neural network, and a prediction model optimized by the genetic algorithm was established. By using the improved genetic algorithm, the position and quantity of the SMA wires were optimized in a three-storey spatial structure, and the dynamic response analysis of the optimal arrangement was carried out. The results show that, compared with the unoptimized neural network prediction model of SMA, the optimized prediction model is in better agreement with the test curve and has higher stability, it can well reflect the effect of loading rate on the superelastic properties of SMA, and is a high precision rate-dependent dynamic prediction model. Moreover, the BP network constitutive model is simple to use and convenient for dynamic simulation analysis of an SMA passive control structure. The controlled structure with optimized SMA wires can inhibit the structural seismic responses more effectively. However, it is not the case that the more SMA wires, the better the shock absorption effect. When SMA wires exceed a certain number, the vibration reduction effect gradually decreases. Therefore, the seismic effect can be reduced economically and effectively only when the number and location of SMA wires are properly configured. When four SMA wires are arranged, the acceptable shock absorption effect is obtained, and the sum of the structural storey drift can be reduced by 44.51%.

16.
Stem Cells Int ; 2021: 9941733, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34725550

RESUMO

SOX12 plays a role in promoting the growth of some tumors; however, its role in osteosarcoma remains unclear. From gene expression omnibus (GEO) and tumor alterations relevant for genomics-driven therapy (TARGET) databases, Kaplan-Meier analyses were conducted to establish relationships between SOX12 expression and osteosarcoma survival and recurrence in osteosarcoma patients. We also performed in vitro and in vivo assays to determine SOX12 function in osteosarcoma etiology. SOX12 expression was increased in osteosarcoma; high SOX12 expression levels were related to a poor prognosis and a high disease recurrence in patients. Moreover, SOX12 expression in osteosarcoma cell lines was increased, similar to osteosarcoma cancer stem cells. We also observed that SOX12 knockdown inhibited the spheroidization and expression of stemness markers in osteosarcoma cells and tumor formation in nude mice. In addition, SOX12 knockdown inhibited JAGGED1 and HES1 expression. Similarly, JAGGED1 knockdown also inhibited the formation of osteosarcoma cancer stem cells into pellets and reduced the expression of stemness markers and tumor formation capabilities in nude mice. Finally, during SOX12 knockdown, JAGGED1 overexpression rescued osteosarcoma cells from spheroidizing. SOX12 promotes stem cell-like phenotypes and osteosarcoma tumor growth by upregulating JAGGED1.

17.
Artigo em Inglês | MEDLINE | ID: mdl-34639417

RESUMO

Mercury is a global pollutant. The mercury exchanges between vegetation and the atmosphere are important for the global mercury cycle. Grassland ecosystems occupy more than 25% of the global land area and have different succession processes and ecological functions. The current research regarding mercury exchanges between forests and the atmosphere have attracted much attention, but the research regarding grasslands tends to be rare. To reveal the characteristics of mercury exchanges in grasslands, this study conducted field in-situ monitoring experiments in a Leymus meadow grassland regions of the Songnen Plains in northeastern China. The exchange flux values of the GEM (gaseous element mercury) between the plants and the atmosphere were measured using a dynamic flux bag method (DFB). The experiments were conducted for the purpose of assessing the mercury flux levels between the vegetation and the atmosphere in a typical Leymus chinensis meadow. The goal was to further the understanding of the change characteristics and influential factors and to describe the source and sink actions and dynamics between the grassland vegetation and the atmosphere. The diurnal variation characteristics were as follows: High during the day and low at night, with peaks generally appearing at noon. The growing period was characterized by absorption peaks of atmospheric mercury by the plants. The breeding period was characterized by the peak release of atmospheric mercury by the plants. The change characteristics were as follows: During the growing period, the duration of the plants in a mercury absorption state exceeded 96.5%, which was represented as the net sink of the atmospheric mercury. During the breeding period, the time of mercury release ranged between 46.4% and 66.8%, making the breeding period the net source of atmospheric mercury. The results of this study's analysis indicated that each environmental factor was correlated with the mercury flux, and the environmental factors had different effects on the mercury flux during the different stages of plant growth. The atmospheric mercury concentration levels were the main factor during the growing period. Atmospheric humidity was the main factor during the breeding period. Solar radiation was the decisive factor during the entire experimental period.


Assuntos
Poluentes Atmosféricos , Mercúrio , Poluentes Atmosféricos/análise , China , Ecossistema , Monitoramento Ambiental , Pradaria , Mercúrio/análise , Melhoramento Vegetal
18.
J Cell Mol Med ; 25(21): 10175-10184, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34612603

RESUMO

Steroid-induced osteoblast apoptosis is a crucial pathological process in steroid-induced osteonecrosis of the femoral head (SONFH). Autophagy can resist apoptosis and AMPK plays an important role in autophagy regulation. Aucubin from the small tree Eucommia ulmoides Oliv., which has a long history of use in orthopaedics and traumatology in Asian medicine, can promote bone formation, but whether it can slow or prevent steroid-osteoblast apoptosis is unclear. Therefore, we investigated the pathogenesis of SONFH and how the osteoblast responds to aucubin under the dexamethasone stimulation. In human femoral head osteonecrosis specimens, we found that the autophage and apoptosis level were increased, and the AMPK signalling was crucial to autophagy. We observed that aucubin could prevent dexamethasone-induced apoptosis in osteoblasts by enhancing the level of autophagy. Further, we confirmed that the regulatory effect of aucubin on autophagy and apoptosis was achieved by activating AMPK signalling. We have demonstrated a mechanism of disease progression and shown that aucubin could enhance autophagy through AMPK signalling to prevent osteoblast apoptosis. These findings provide a basis for the further investigation of the potential therapeutic role of aucubin in the SONFH.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Autofagia/efeitos dos fármacos , Glucosídeos Iridoides/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Substâncias Protetoras/farmacologia , Esteroides/farmacologia , Proteínas Quinases Ativadas por AMP/genética , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Relação Dose-Resposta a Droga , Humanos , Imunofenotipagem , Camundongos , Osteoblastos/ultraestrutura , Fosforilação
19.
Biology (Basel) ; 10(9)2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34571793

RESUMO

Mercury (Hg) is a global pollutant that may potentially have serious impacts on human health and ecologies. The gaseous elemental mercury (GEM) exchanges between terrestrial surfaces and the atmosphere play important roles in the global Hg cycle. This study investigated GEM exchange fluxes over two land cover types (including Artemisia anethifolia coverage and removal and bare soil) using a dynamic flux chamber attached to the LumexR RA915+ Hg analyzer during the growing season from May to September of 2018, in which the interactive effects of plant coverage and meteorological conditions were highlighted. The daily mean ambient levels of GEM and the total mercury concentrations of the soil (TSM) were determined to be 12.4 ± 3.6 to 16.4 ± 5.6 ng·m-3 and 32.8 to 36.2 ng·g-1, respectively, for all the measurements from May to September. The GEM exchange fluxes (ng·m-2·h-1) during the five-month period for the three treatments included the net emissions from the soil to the atmosphere (mean 5.4 to 7.1; range of -27.0 to 47.3), which varied diurnally, with releases occurring during the daytime hours and depositions occurring during the nighttime hours. Significant differences were observed in the fluxes between the vegetation coverage and removal during the growing months (p < 0.05). In addition, it was determined that the Hg fluxes were positively correlated with the solar radiation and air/soil temperature levels and negatively correlated with the air relative humidity and soil moisture under all the conditions (p < 0.05). Overall, the results obtained in this study demonstrated that the grassland soil served as both a source and a sink for atmospheric Hg, depending on the season and meteorological factors. Furthermore, the plants played an important inhibiting role in the Hg exchanges between the soil and the atmosphere.

20.
Mater Sci Eng C Mater Biol Appl ; 128: 112347, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474897

RESUMO

Although the use of bioactive ions and proteins are crucial for bone defect repair, delivering them in a stable and controlled manner remains challenging. To achieve controlled delivery of osteogenic active factor, we developed a novel double network (DN) hydrogel capable of co-delivering Mg2+ ions and BMP2 in a controlled localized manner. This DN hydrogel was composed of poly (acrylamide) and chitosan, in which the poly (acrylamide) was cross-linked via covalent bond and the chitosan was grafted using bisphosphonate (BP) to form metal coordination bonds with Mg2+ ions. Due to this dynamic dissociation and re-association of the "BP-Mg2+" coordination bond, it was possible to deliver Mg2+ ions in a stable and controlled manner. Additionally, the obtained DN hydrogel exhibited an effective tensile strength (0.62 MPa), perfect stretchability (973% fracture strain), and good creep and recovery properties due to the dynamic cross-linking effect of "BP-Mg2+". Additionally, the hydrogel could synergistically promote the proliferation and differentiation of mouse embryo osteoblast precursor cells (MC3T3-E1 cells) in vitro via the BMP2/Wnt pathway. In the skull defect rat model, this positive delivery government of Mg2+ ions and BMP2 synergistically accelerated bone regeneration. In conclusion, this dynamic cross-linked hydrogel containing Mg2+ ions established a new platform for the sustained release of osteogenesis factor and accelerated the bone regeneration process.


Assuntos
Hidrogéis , Magnésio , Animais , Proteína Morfogenética Óssea 2 , Regeneração Óssea , Diferenciação Celular , Íons , Camundongos , Osteogênese , Ratos
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