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1.
J Biomater Sci Polym Ed ; : 1-17, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39225005

RESUMO

Graphene oxide (GO) is widely used in bone tissue engineering due to its good biocompatibility and proliferation, and is often used in combination with other hydrogels, which not only reduces the cytotoxicity of GO but also improves the mechanical properties of the hydrogels. We developed injectable carboxymethyl chitosan (CMC)/hydroxyethyl cellulose (HEC)/ß-tricalcium phosphate (ß-TCP)/GO hydrogel via hydrogen bonding cross-linked between (CMC) and (HEC), also, calcium cross-linked by ß-TCP was also involved to further improvement of mechanical properties of the hydrogel, and incorporate different concentration of GO in these hydrogel systems. The characterization of the novel hydrogel was tested by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The swelling ratio and mechanical properties were investigated, the results showed that the addition of GO was able to reduce the swelling rate of hydrogels and improve their mechanical properties, with the best effect in the case of 1 mg/mL content. In vivo experimental studies showed that the hydrogel significantly promoted the osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs), with the best effect at a concentration of 2 mg/mL. The results of the cellular experiments were similar. Therefore, the novel environment-friendly and non-toxic injectable CMC/HEC/ß-TCP/GO hydrogel system may have potential applications in bone tissue engineering.

2.
Mar Pollut Bull ; 208: 116979, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39303552

RESUMO

Antibiotic resistance genes (ARGs) are an important class of pollutants in the environment. This study investigated the characteristics and ecological effects of ARGs in the Bohai Sea sediments. The results showed that ARGs are widely distributed, and exhibit significant spatial and subtype variations, with absolute abundance following the decreasing order of Liaodong Bay, Laizhou Bay, Bohai Bay, and Bohai Strait. Tetracycline ARGs dominated, comprising 50 % to 62 % of all ARGs, with tetM having the highest abundance at 1.43 × 107 copies/g. Symbiotic network analysis revealed that the phyla Deinococcota, Dadabacteria were serve as the primary likely host of ARGs. The ARGs have a wide range of potential hosts, and bacteria often carry multiple ARGs, enhancing the mobility and ecological niche adaptation of ARGs. This study will provide an important reference for assessing ARGs pollution in semi-enclosed seas.


Assuntos
Resistência Microbiana a Medicamentos , Sedimentos Geológicos , Sedimentos Geológicos/microbiologia , China , Resistência Microbiana a Medicamentos/genética , Monitoramento Ambiental , Genes Bacterianos , Bactérias/genética , Antibacterianos , Poluentes Químicos da Água/análise , Farmacorresistência Bacteriana/genética
3.
Sci Total Environ ; 951: 175684, 2024 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-39173766

RESUMO

The demographic traits of an organism are key components of its fitness and life history theory aims at identifying the environmental drivers underlying the evolution of life history strategies. For fishes, the equilibrium species, those investing into larval survival (large eggs, parental care) rather than into absolute fecundity, are hypothesized to have evolved in stable and predictable environments with high biotic pressure. Human induced nutrient enrichment in many lakes around the world makes them increasingly subjected to perturbations such as anoxia and toxic algal blooms. We hypothesized that eutrophication results in lakes becoming more unstable, unpredictable and less resource-limited, in turn less favorable to equilibrium species. Another hypothesis states that lacustrine environment stability increases with ecosystem size. This study presents the first attempt to compare the two hypotheses in a group of 26 lakes. We found that the population abundance of equilibrium species was negatively related to increasing eutrophication. Long-lived and highly fecund periodic species responded more positively to eutrophication than short lived opportunistic species, with no parental care. This result could be demonstrated by seasonality in primary productivity which favors periodic species, disconnection from the river which prevents good colonist (i.e., opportunistic) species to (re)-establish after perturbation events, and predation by periodic species on opportunistic species. In contrast, we found no support for the ecosystem size hypothesis. Overall, we showed that human driven eutrophication affected species according to their life history strategies, reinforcing the usefulness of life history theory as a framework for assessing fish community response to a large array of human perturbations. More generally, our study emphasizes the importance of species traits to assess, explain, and predict community responses to human and natural perturbations.


Assuntos
Eutrofização , Peixes , Lagos , Animais , Características de História de Vida , Ecossistema , Monitoramento Ambiental/métodos
4.
Sci Rep ; 14(1): 17790, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39090174

RESUMO

A specific optimized configuration for low threshold organic semiconductor laser based on a holographic polymer dispersed liquid crystal (HPDLC) transmission grating was demonstrated. Here the organic semiconductor films and phase separated liquid crystal (LC) molecules were oriented along the direction of the HPDLC grating grooves. The influence of the organic semiconductor chain orientation and the excitation polarization on the optical properties of the materials has been investigated. Especially, when polymer chain orientation, LC molecules and pump light polarization are consistent with the direction of the grating grooves, the performance of the outgoing laser is greatly improved. Up to 9.78% conversion efficiency with a threshold lower to 0.12 µJ/pulse can be obtained, indicating their potential for high-performance organic optoelectronics.

5.
Mar Environ Res ; 200: 106648, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39043062

RESUMO

The oxygen minimum zone (OMZ) is an important representative of marine hypoxia in the open ocean, and it is developing rapidly under the context of global warming. However, the research on OMZ in the Western Pacific is still deficient. This study focused on its basic characteristics and impact on the degradation of particulate matters in the M4 seamount of Western Pacific. The results showed that the OMZ is located at 290-1100 m, just below the high-salinity area and thermocline. The M4 seamount has a weak impact on the OMZ, and only the bottom waters contacting with the seamount have a weak decrease in dissolved oxygen (DO). With the increase of water depth, particulate nitrogen and phosphorus decrease first above and in the OMZ and then increase below the OMZ, while particulate organic carbon (POC) gradually decreases. The low-DO environment in the OMZ is not conducive to the degradation of particulate matters, which promotes the transport of particulate matters to the deep sea, and most particulate matters have the lowest degradation rate here. The waters above the OMZ have the fastest change rate of particulate matters, in which particulate organic phosphorus (POP) and particulate inorganic phosphorus (PIP) are preferentially degraded, and the degradation rate of them is significantly higher than particulate organic nitrogen (PON) and particulate inorganic nitrogen (PIN). The particulate nitrogen and phosphorus in the waters below the OMZ continue to increase, while PON/total particulate nitrogen (TPN) and POP/total particulate phosphorus (TPP) increase significantly, and the increase rate of PIN and PIP is far lower than PON and POP, indicating that the increase of organic matters in particulate matters is more significant. It is speculated that this phenomenon might be related to the input of Antarctic Bottom Water or the in-situ production by microorganisms. This study revealed the relationship between OMZ and different particulate matters, which may provide a valuable pathway for the biogeochemical effects of OMZ in the Western Pacific.


Assuntos
Monitoramento Ambiental , Nitrogênio , Oxigênio , Material Particulado , Fósforo , Água do Mar , Material Particulado/análise , Oxigênio/análise , Oxigênio/metabolismo , Fósforo/análise , Água do Mar/química , Nitrogênio/análise , Oceano Pacífico , Poluentes Químicos da Água/análise
6.
RSC Adv ; 14(17): 11908-11913, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38623298

RESUMO

Microplastics (MPs) as the formidable pollutants with high toxicity and difficult degradation may threaten the aquaculture industry and human health, making it highly necessary to develop the effective removal methods. In this article, Fe3O4 nanoparticles (NPs) were initially fabricated with mesoporous structure, but showing undesirable adsorption efficiencies for the adsorption of MPs (lower than 70%). Inspired by the reefs-rebuilding corals acting as the sinks for various marine pollutants like plastic, Fe3O4 NPs were coated further with adhesive polymerized dopamine (PDA) yielding Fe3O4@PDA absorbents. Unexpectedly, it was discovered that the corals-mimicking absorbents so formed could allow for the removal of MPs with dramatically enhanced efficiencies up to 98.5%, which is over about 30% higher than those of bare Fe3O4 NPs. Herein, the PDA shells might conduct the increased adhesion to MPs, presumably through the formation of hydrogen bonding, π-π stacking, and hydrophobic interactions. A fast (within 20 min) and stable adsorption of MPs can also be expected, in addition to the PDA-improved environmental storage of Fe3O4 NPs. Subsequently, the Fe3O4@PDA adsorbents were utilized to remove MPs from different water sources with high efficiencies, including pure water, suburban streams, village rivers, lake water, inner-city moats, and aquaculture water. Such a magnet-recyclable adsorbent may provide a new way for rapid, effective, and low-cost removal of MPs pollutants from various water systems.

7.
Mar Pollut Bull ; 201: 116241, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38479325

RESUMO

Nutrients directly control the level of primary productivity and are crucial for the stability of marine ecosystems. Focusing on the survey results in August 2020 of the Yangtze River Estuary, this study elucidated the distribution characteristics and controlling factors of three nutrients: NO3-N, PO4-P, SiO3-Si. The results showed that the concentrations of NO3-N, PO4-P, SiO3-Si in the study area were generally higher near the shore than far shore, with average concentrations of 11.40, 0.70, and 23.73 µmol/L, respectively. The ocean currents drove the distribution of nutrients, and the transport of CDW and YSCC increased the nutrient levels. The resuspension of sediment caused by factors such as terrain and weather may lead to an abnormal increase in nutrients in the bottom waters. The main controlling factors of the three nutrients were different. NO3-N was significantly affected by human activities, PO4-P and SiO3-Si were mainly affected by natural factors.


Assuntos
Estuários , Rios , Humanos , Ecossistema , Estações do Ano , Nutrientes , China , Monitoramento Ambiental
8.
Sci Total Environ ; 913: 169562, 2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38142998

RESUMO

In eutrophic lake ecosystems, cyanobacteria typically lead to unbalanced phytoplankton community structure and low dietary quality for consumers at higher trophic levels. However, it still remains poorly understood how zooplankton manage to respond to seasonal and spatial differences in lake trophic gradients and temperature factors to retain highly required dietary nutrients from phytoplankton. In this field study, we investigated seston and different size classes of zooplankton of temperate and subtropical large lakes of different trophic conditions in China. We used fatty acids (FA) as dietary nutrients from seston to zooplankton to investigate how eutrophication affects the FA composition of various zooplankton size classes. This study revealed a curvilinear relationship between total phosphorus (TP) and polyunsaturated fatty acids (PUFA) contents of edible phytoplankton ("seston") across 3 seasons and 2 climatic areas. The PUFA content of seston increased until mesotrophic lake conditions (TP: 11-20 µg L-1), after which the dietary provision of PUFA for respective consumers declined. Seston FA, rather than trophic condition or water temperature, primarily predicted changes in zooplankton FA, while this predictive power decreased with zooplankton size. Despite increasing eutrophic lake conditions, LC-PUFA content of the zooplankton consistently increased per unit biomass. The results indicate that the nutritional value of phytoplankton was highest in mesotrophic lakes, and lake zooplankton selectively increased their LC-PUFA retention with body size and/or were able to convert dietary FA endogenously to meet their size-specific FA demands, independent of lake location or time (season) or the measured trophic condition of the lake (from oligo- to eutrophic).


Assuntos
Cadeia Alimentar , Lagos , Animais , Lagos/química , Ecossistema , Ácidos Graxos , Fitoplâncton , Zooplâncton/química , Ácidos Graxos Insaturados , Biomassa
9.
Opt Express ; 31(25): 41292-41300, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-38087531

RESUMO

What we believe to be a novel integrated circular polarization dynamic converter (CPDC) is proposed based on the four-layer mirror symmetry structure. By designing the twisted structure and rearranging the orientation direction of liquid crystal molecules for each layer, the application wavelength range could be broadened. For the viewing angle expansion, negative birefringent films are selected to compensate for the retardation deviation under oblique incidence. Finally, the particle swarm algorithm is used to optimize the whole configuration, and the polarization conversion efficiency calculated by the finite element method (FEM) can achieve 90% in the wavelength range from 320 nm to 800 nm at an ultrawide view of 160°. Compared with traditionally active liquid crystal waveplates, the design has potential advantages in both wavelength and field of view (FOV) and provides the possibility for the integrated and flimsy fabrication of devices.

10.
Ying Yong Sheng Tai Xue Bao ; 34(11): 3114-3126, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37997423

RESUMO

Fluoroquinolone antibiotics (FQs) are one of the most widely used antibiotics, which are new pollutants with 'pseudo persistence' in the environment, causing great ecological risks. FQs could change the structure and function of microbial communities and affect nitrogen cycling mediated by microorganisms. Consequently, FQs would change the composition of various types of nitrogen in the environment and exert a significant impact on the global nitrogen cycling. We encapsulated the distribution of FQs in the environment and its impacts on nitrogen cycling mediated by microorganisms, explained the role of FQs in each key process of nitrogen cycling, aiming to provide an important reference for revealing the ecological effects of FQs. Generally, FQs could be detected in various environmental media, with significant differences in the concentration and types of FQs in different environments. Ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin are the four types of FQs with the highest detection frequency and concentration. The effect of FQs on nitrogen cycling deeply depends on typical characteristics of concentration and species. FQs mainly inhibit nitrification by reducing the abundance of amoA gene related to ammoxidation process and the abundance and composition of ammoxidation bacteria. FQs inhibits nitrification by reducing the abundance and composition of microbial communities. The denitrification process is mainly inhibited due to the reduction of the activity of related enzymes and the abundance of genes such as narG, nirS, norB, and nosZ genes, as well as the abundance and composition of denitrifying functional microorganisms. The process of anammox is restricted due to the reduction of the abundance, composition and hzo gene abundance of anaerobic anammox bacteria. FQs lead to the reduction of active nitrogen removal and the increase of N2O release in the environment, with further environmental problems such as water eutrophication and greenhouse effect. In the future, we should pay attention to the effects of low concentration FQs and complex antibiotics on the nitrogen cycling, and focus on the effects of FQs on the changes of nitrogen cycle-related microbial monomers and communities.


Assuntos
Fluoroquinolonas , Ciclo do Nitrogênio , Fluoroquinolonas/química , Antibacterianos/farmacologia , Antibacterianos/química , Poluição Ambiental , Nitrogênio , Desnitrificação
11.
Ying Yong Sheng Tai Xue Bao ; 34(8): 2274-2284, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37681392

RESUMO

Sulfonamides (SAs) are the first broad-spectrum synthetic antimicrobial agents used in human health and veterinary medicine. The majority of SAs entering human body is discharged into aquatic environment in the form of parent material or metabolites. The residues of SAs and their metabolites in the aquatic environment and the development of drug resistance can be serious threats to ecosystems and human health. We summarized recent advances in the research of SAs. The main metabolite types of SAs and the distribution characteristics of metabolites in different aquatic environments were introduced. The ecotoxicology of SAs metabolites, especially the distribution and hazards of sulfonamide resistance genes (sul-ARGs), were discussed with emphasis. Finally, the future research works were proposed. This paper could provide basic information for further research on SAs.


Assuntos
Ecossistema , Ecotoxicologia , Humanos , Sulfanilamida , Sulfonamidas/toxicidade
12.
Ying Yong Sheng Tai Xue Bao ; 34(6): 1680-1692, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37694431

RESUMO

Synthetic fluoroquinolones (FQs) are the third most commonly used antibiotics in the world and play an extremely important role in antibacterial drugs. The excessive use and discharge will alter ecological environment, with consequence on human health and global sustainable development. It is therefore of great significance for scientific use and management of FQs to systematically understand their biogeochemical behavior and eco-environmental effects. After drug administration in humans and animals, only a small part of FQs are transformed in vivo. The main transformation processes include formylation, acetylation, oxidation and cleavage of piperazine ring, defluorination and decarboxylation of aromatic core ring, etc. About 70% of the original drug and a small amount of transformed products would be migrated to the environment through excretion. After entering the environment, FQs and their transformation products mainly exist in environmental media such as water, soil and sediment, and undergo migration and transformation processes such as adsorption, photolysis and biodegradation. Adsorption facilitates transfer of FQs from medium to another. The photolysis mainly affects the C7-amine substituents of FQs, whereas the core structure of FQs remains intact. Biodegradation mainly refers to the degradation of FQs by microorganisms and microalgae, including piperazine modification of the piperazine ring such as acetylation and formylation, partial or complete ring cleavage, core structure decarboxylation, defluorination and conjugation formation. The migration and transformation processes of FQs cannot completely eliminate them from the environment. Instead, they would become "pseudo-persistent" pollutants, which seriously affect the behavior, growth and reproduction of algae, crustaceans and fish, change biogeochemical cycle, destroy aquatic environment, and stimulate microbial resistance and the generation of resistance genes. In the future, more in-depth studies should be conducted on the environmental behavior of FQs and their impacts on ecological environment, the risk assessment of microbial resistance and resistance genes of FQs, and the mechanism and effect of micro-biodegradation of FQs.


Assuntos
Clima , Fluoroquinolonas , Animais , Humanos , Antibacterianos , Biodegradação Ambiental , Piperazinas
13.
ACS Omega ; 8(36): 32907-32916, 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37720790

RESUMO

In general, although abundant literature studies are available on epoxy resin systems, a complete description of the curing kinetics in epoxy-cyanate ester composites relevant to the microelectronics industry is still lacking. Herein, curing behaviors of Ajinomoto build-up films, which are epoxy/silica composites, were studied by the non-isothermal differential scanning calorimetry method, and then, three non-isothermal curing kinetics models and model-free curing methods were used to analyze curing behaviors. In addition, a copper layer was also deposited onto the surface of the build-up film, and its interfacial adhesion property was also analyzed at different pre-curing conditions. The results showed that the curing reaction of the build-up film contains two curing reaction processes, and the first curing process is suited for the autocatalytic curing model, while the other curing process is suited for the Kamal curing kinetics model. Three model-free curing methods were used to calculate the activating energy at different degrees of curing, which indicated that the activating energy is variable during the whole curing process. The interfacial adhesion strength between the build-up film and copper layer decreased with the increase in the degree of curing, which is attributed to the contribution of mechanical anchoring. This work will offer guidance in curing behaviors for improving interfacial bonding force and controlling warpage behavior for chip substrates in the future.

14.
Front Genet ; 14: 1163162, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37476411

RESUMO

Sarcopenia and osteoporosis, two degenerative diseases in older patients, have become severe health problems in aging societies. Muscles and bones, the most important components of the motor system, are derived from mesodermal and ectodermal mesenchymal stem cells. The adjacent anatomical relationship between them provides the basic conditions for mechanical and chemical signals, which may contribute to the co-occurrence of sarcopenia and osteoporosis. Identifying the potential common crosstalk genes between them may provide new insights for preventing and treating their development. In this study, DEG analysis, WGCNA, and machine learning algorithms were used to identify the key crosstalk genes of sarcopenia and osteoporosis; this was then validated using independent datasets and clinical samples. Finally, four crosstalk genes (ARHGEF10, PCDH7, CST6, and ROBO3) were identified, and mRNA expression and protein levels of PCDH7 in clinical samples from patients with sarcopenia, with osteoporosis, and with both sarcopenia and osteoporosis were found to be significantly higher than those from patients without sarcopenia or osteoporosis. PCDH7 seems to be a key gene related to the development of both sarcopenia and osteoporosis.

15.
RSC Adv ; 13(20): 13991-14000, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37181518

RESUMO

Graphene oxide (GO) was utilized as an additive to encourage the development of early strength in order to improve steel slag cement's low early strength. This work investigates the compressive strength and setting time of cement paste. The hydration process and its products were explored using hydration heat, low-field NMR, and XRD; in addition, the internal microstructure of the cement was analyzed utilizing MIP, SEM-EDS, and nanoindentation testing technologies. The results demonstrated that the inclusion of SS retarded cement's hydration, leading to a degradation of compressive strength and microstructure. However, the addition of GO was able to accelerate the hydration of steel slag cement, giving rise to a reduction in total porosity, a strengthening of the microstructure, and an improvement in compressive strength, particularly the material developing trends at the early stage. Due to its nucleation and filling capabilities, GO increases the total amount of C-S-H gels present in the matrix, specifically vast amounts of C-S-H gels with high density. It has been established that the addition of GO is capable of greatly enhancing steel slag cement's compressive strength.

16.
Int J Nanomedicine ; 18: 1875-1895, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37051313

RESUMO

Background: Immune responses and osteogenesis differentiation induced by implants are crucial for bone tissue regeneration. Consideration of only one of those properties is not sufficient. To investigate the synergistic actions, we designed alginate/graphene oxide/sericin/nanohydroxyapatite (Alg/GO/Ser/nHAP) nanocomposite hydrogels with both osteoimmunomodulatory and osteoinductive activities. This study aimed to explore the effect of hydrogel with osteoimmunomodulatory properties on promoting osteogenesis of bone marrow stem cells (BMSCs). Methods: Alg/GO/Ser/nHAP nanocomposite hydrogel was fabricated and was characterized by SEM, FTIR, XRD, stress-strain, rheology, swelling and degradation. After the impact of sericin on M2 macrophage polarization was identified, the BMSCs viability and adhesion were evaluated by CCK8 assay, live/dead staining, cytoskeleton staining. The cell osteogenic differentiation was observed by ALP/ARS staining, immunofluorescence staining, RT-PCR, and Western blotting, respectively. Rat cranial defect model was used to assess osteoimmunomodulatory effects of scaffolds in vivo by micro­computed tomographic, histological, and immunohistochemical analyses after 8 weeks of healing. Results: In vitro experiments revealed that the hydrogel presented desirable mechanical strength, stability, porosity, and biocompatibility. Significantly, sericin and nHAP appeared to exert synergistic effects on bone regeneration. Sericin was observed to inhibit the immune response by inducing macrophage M2-type polarization to create a positive osteoimmune microenvironment, contributing to improving osseointegration at the bone-implant interface to promote osteogenesis. However, the osteogenic differentiation in rat BMSCs was further enhanced by combining nHAP and sericin in the nanocomposite hydrogel. Eventually, the hydrogel was implanted into the rat cranial defect model, assisting in the reduction of local inflammation and efficient bone regeneration. Conclusion: The nanocomposite hydrogel stimulated bone formation by the synergistic effects of immunomodulation of macrophage polarization by sericin and direct osteogenic induction by nHAP, demonstrating that such a scaffold that modulates the osteoimmune microenvironment to promote osteogenesis is a promising approach for the development of bone tissue engineering implants in the future.


Assuntos
Osteogênese , Sericinas , Ratos , Animais , Hidrogéis/farmacologia , Hidrogéis/química , Sericinas/farmacologia , Durapatita/farmacologia , Durapatita/química , Nanogéis , Alicerces Teciduais/química , Regeneração Óssea , Diferenciação Celular , Imunidade , Imunomodulação
17.
Opt Express ; 31(4): 6615-6622, 2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36823913

RESUMO

A high-speed circular polarization converter (CPC) with a wide field of view (FOV) and wavelength range is designed and fabricated in this paper. The multi-waveplate combined structure is applied to constitute the basic configuration of the CPC for broadening the wavelength range. An electrically suppressed helix ferroelectric liquid crystal (ESHFLC) material with fast response is used as a medium for dynamic polarization operation. The compensation films are used to expand the FOV by attaching to the configuration. The simulation results demonstrate that the optimized CPC structure can achieve over 97% orthogonal circular polarization conversion efficiency in 300 nm bandwidth at a 90° viewing cone for both working states. Finally, we have experiments and the results show well consistency with the theoretical results.

18.
Int J Mol Sci ; 24(3)2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36769013

RESUMO

Zwitterionic materials are widely applied in the biomedical field due to their excellent antimicrobial, non-cytotoxicity, and antifouling properties but have never been applied in bone tissue engineering. In this study, we synthesized a novel zwitterionic hydrogel incorporated with graphene oxide (GO) using maleic anhydride (MA) as a cross-linking agent by grafted L-cysteine (L-Cys) as the zwitterionic material on maleilated chitosan via click chemistry. The composition and each reaction procedure of the novel zwitterionic hydrogel were characterized via X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FT-IR), while the morphology was imaged by scanning electron microscope (SEM). In vitro cell studies, CCK-8 and live/dead assay, alkaline phosphatase activity, W-B, and qRT-CR tests showed zwitterionic hydrogel incorporated with GO remarkably enhanced the osteogenic differentiation of bone mesenchymal stem cells (BMSCs); it is dose-dependent, and 2 mg/mL GO is the optimum concentration. In vivo tests also indicated the same results. Hence, these results suggested the novel zwitterionic hydrogel exhibited porous characteristics similar to natural bone tissue. In conclusion, the zwitterionic scaffold has highly biocompatible and mechanical properties. When GO was incorporated in this zwitterionic scaffold, the zwitterionic scaffold slows down the release rate and reduces the cytotoxicity of GO. Zwitterions and GO synergistically promote the proliferation and osteogenic differentiation of rBMSCs in vivo and in vitro. The optimal concentration is 2 mg/mL GO.


Assuntos
Grafite , Células-Tronco Mesenquimais , Osteogênese , Engenharia Tecidual/métodos , Hidrogéis/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Osso e Ossos , Grafite/farmacologia , Grafite/química , Diferenciação Celular , Alicerces Teciduais
19.
Mar Pollut Bull ; 187: 114579, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36634538

RESUMO

The continuous expansion of the oxygen minimum zone (OMZ) is a microcosm of marine hypoxia problem. Based on a survey in M4 seamount area of Tropical Western Pacific Ocean, the effects of thermodynamic parameters on OMZ were discussed. The study showed thermodynamic parameters mainly affect the upper oxycline of OMZ. The increase in temperature aggravates seawater stratification, which not only shallows oxycline but also increases the strength of DO stratification, promoting the expansion of OMZ. Based on relationships between thermodynamic parameters, water mass and DO, OMZ in this area is defined as follows: the water layer with low DO between the lower boundary of high-salt area and 1000 m. Moreover, the study showed that though there is no "seamount effect" on a scale of 3000 m, low-value areas of DO form at the bottom of seamount. This study will provide an evidence for expansion of OMZ exacerbated by global warming.


Assuntos
Oxigênio , Água do Mar , Oceano Pacífico , Oxigênio/análise , Temperatura , Água
20.
Sci Total Environ ; 857(Pt 3): 159651, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36280085

RESUMO

Rapid anthropogenic nutrient enrichment has caused widespread ecological problems in aquatic ecosystems and the resulting eutrophication has dramatically changed fish communities throughout the world. However, few studies addressed how fish communities responded to eutrophication in terms of multidimensional functional and taxonomic structure, especially how eutrophication acted as an environment filter on functional traits. The aim of the present study was to investigate the effects of eutrophication on fish species composition, community metrics and species functional traits in 26 shallow lakes from the middle reaches of Yangtze River basin, China. This study validated that eutrophication is an important factor shaping the fish community structure. Regression analyses showed that eutrophication favored higher total biomass and lower functional diversity of fish communities but had little effect on species richness. Despite the fact that some pelagic zooplanktivorous species were more abundant in the most eutrophic lakes, multivariate analyses of the relationships between species traits and environmental variables revealed weak relationships between feeding traits and eutrophication. In contrast, species with a benthic life stage were negatively associated with eutrophication while those with a large body size and high absolute fecundity showed the opposite trend. Due to demersal habitat degradation, and to a lesser degree, to changes in trophic resources availability, eutrophication caused functional simplification of fish communities by increasing functional traits homogeneity among the most tolerant species. Some relationships between functional traits and eutrophication well established in the western palearctic have not been observed in this study, emphasizing the importance of biases resulting from specific evolutionary histories. This work will provide useful insights on on-going restoration and management of shallow lakes in the Yangtze River basin.


Assuntos
Ecossistema , Eutrofização , Animais , Lagos , Peixes , Rios/química , China
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