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1.
Antimicrob Agents Chemother ; 68(7): e0031124, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38874346

RESUMO

The emergence of clinically drug-resistant malaria parasites requires the urgent development of new drugs. Mosquitoes are vectors of multiple pathogens and have developed resistance mechanisms against them, which often involve antimicrobial peptides (AMPs). An-cecB is an AMP of the malaria-transmitting mosquito genus Anopheles, and we herein report its antimalarial activity against Plasmodium falciparum 3D7, the artemisinin-resistant strain 803, and the chloroquine-resistant strain Dd2 in vitro. We also demonstrate its anti-parasite activity in vivo, using the rodent malaria parasite Plasmodium berghei (ANKA). We show that An-cecB displays potent antimalarial activity and that its mechanism of action may occur through direct killing of the parasite or through interaction with infected red blood cell membranes. Unfortunately, An-cecB was found to be cytotoxic to mammalian cells and had poor antimalarial activity in vivo. However, its truncated peptide An-cecB-1 retained most of its antimalarial activity and avoided its cytotoxicity in vitro. An-cecB-1 also showed better antimalarial activity in vivo. Mosquito-derived AMPs may provide new ideas for the development of antimalarial drugs against drug-resistant parasites, and An-cecB has potential use as a template for antimalarial peptides.


Assuntos
Anopheles , Antimaláricos , Plasmodium berghei , Plasmodium falciparum , Animais , Antimaláricos/farmacologia , Anopheles/efeitos dos fármacos , Anopheles/parasitologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium berghei/efeitos dos fármacos , Camundongos , Cecropinas/farmacologia , Peptídeos Antimicrobianos/farmacologia , Peptídeos Antimicrobianos/química , Malária/tratamento farmacológico , Malária/parasitologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/parasitologia , Humanos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/parasitologia , Feminino , Proteínas de Insetos/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Cloroquina/farmacologia , Testes de Sensibilidade Parasitária
2.
Malar J ; 22(1): 163, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37226272

RESUMO

BACKGROUND: Malaria is a worldwide infectious disease. For countries that have achieved malaria elimination, the prevention of re-establishment due to infections in returned travellers has become important. The accurate and timely diagnosis of malaria is the key in preventing re-establishment, and malaria rapid diagnostic tests (RDTs) are frequently used due to their convenience. However, the RDT performance in Plasmodium malariae (P. malariae) infection diagnosis remains unknown. METHODS: This study analysed epidemiological features and diagnosis patterns of imported P. malariae cases from 2013 to 2020 in Jiangsu Province and evaluated the sensitivity of four parasite enzyme lactate dehydrogenase (pLDH)-targeting RDTs (Wondfo, SD BIONLINE, CareStart and BioPerfectus) and one aldolase-targeting RDT(BinaxNOW) for P. malariae detection. Furthermore, influential factors were investigated, including parasitaemia load, pLDH concentration and target gene polymorphisms. RESULTS: The median duration from symptom onset to diagnosis among patients with P. malariae infection was 3 days, which was longer than that with Plasmodium falciparum (P. falciparum) infection. The RDTs had a low detection rate (39/69, 56.5%) among P. malariae cases. All tested RDT brands had poor performance in P. malariae detection. All the brands except the worst-performing SD BIOLINE, achieved 75% sensitivity only when the parasite density was higher than 5000 parasites/µL. Both pLDH and aldolase showed relatively conserved and low gene polymorphism rates. CONCLUSIONS: The diagnosis of imported P. malariae cases was delayed. The RDTs had poor performance in P. malariae diagnosis and may threaten the prevention of malaria re-establishment from returned travellers. The improved RDTs or nucleic acid tests for P. malariae cases are urgently needed for the detection of imported cases in the future.


Assuntos
Malária Falciparum , Malária , Humanos , Plasmodium malariae , Testes de Diagnóstico Rápido , Malária/diagnóstico , China , Frutose-Bifosfato Aldolase , Aldeído Liases , L-Lactato Desidrogenase
3.
Ecotoxicol Environ Saf ; 237: 113553, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483147

RESUMO

Insecticide-based vector control measures play an important role in the prevention and control of insect-borne infectious diseases such as malaria; however, insecticide resistance has become a severe global problem for vector control. To date, the metabolic mechanism by which Anopheles sinensis, the most widely distributed malaria vector in China and Asia, detoxifies insecticides is not clear. In this study, the molecular metabolite changes in both the larval and adult stages of deltamethrin susceptible (DS) and deltamethrin-resistant (DR) An. sinensis mosquitoes were analysed by using liquid chromatography tandem mass spectrometry (LC-MS/MS) after exposure to deltamethrin. There were 127 differential metabolites in larval DR An. sinensis and 168 in adults. Five metabolites (glycerophosphocholine, deoxyguanosine, DL-methionine sulfoxide, D-myo-inositol-3-phosphate and N-acetyl-alpha-D-glucosamine1-phosphate) were downregulated in both DR larvae and adults, and one metabolite (aspartyl-glutamine) was upregulated, and the ratio of down- and up-regulation of these metabolites was 5:1. The differential metabolites between the DS and DR mosquitos were mainly classified into organic oxygen compounds, carboxylic acids and their derivatives, glycerophospholipids and purine nucleotides, and the common pathway enriched in both the larval and adult DR An. sinensis was glycerophospholipid metabolism. The findings of this study provide further mechanistic understanding of insecticide resistance in An. sinensis.


Assuntos
Anopheles , Inseticidas , Malária , Piretrinas , Animais , Cromatografia Líquida , Resistência a Inseticidas , Inseticidas/toxicidade , Larva , Malária/prevenção & controle , Metaboloma , Mosquitos Vetores , Nitrilas/toxicidade , Piretrinas/toxicidade , Espectrometria de Massas em Tandem
4.
Environ Monit Assess ; 192(1): 29, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31823019

RESUMO

Industrial parks, which are characterized as a group of industrial businesses designed to meet the concomitant demands of different organizations within an area, have played an important role in the national development strategies of many countries. Industrial parks have received increasingly more attention over time. Nevertheless, few scholars have visually analyzed global scientific data. This paper quantitatively and visually examines global academic research papers on industrial parks from 1987 to 2016 by using a bibliometric analysis. A total of 1823 papers from Science Citation Index Expanded and Social Sciences Citation Index databases were analyzed. The distributions of authorship, keywords, countries/territories, and institutes were generated. According to data from Science Citation Index Expanded and Social Sciences Citation Index databases, the top five most productive authors (i.e., Geng Y. with 22 articles, Fujita T. with 17, El-Halwagi M.M. with 15, Zhang Y. with 14, and Tan R.R. with 12) have contributed significantly to industrial park research. Papers on industrial park research have mainly been from China, the USA, and Taiwan. The dominant keywords from industrial park research from 1987 to 2016 are "China", "system", "heavy metal", and "eco-industrial park". These keywords will be the hot topics in industrial park research in the future. The research findings can provide a reference for understanding the research development process and trends in analyses in the field of industrial parks.


Assuntos
Bibliometria , Instalações Industriais e de Manufatura/estatística & dados numéricos , Pesquisa/tendências , Terminologia como Assunto
5.
Environ Monit Assess ; 191(7): 412, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31165935

RESUMO

As a main type of urban construction land, urban-industrial land is used to provide the judging criteria for construction land scale in the planning period when urban population, industrial development, investment scale, and other conditions are uncertain in China; however, research on expected indicator such as urban-industrial land in overall land use plan mainly focuses on qualitative analysis; quantitative analysis research has not yet been carried out. Using MATLAB R2016a software modeling tools to establish GM (1, 1) model and RBF neural network model, respectively, this paper predicted the demand of urban-industrial land in Beijing-Tianjin-Hebei Urban Agglomeration. Comparing the predicated results with the actual value of urban-industrial land in Beijing, Tianjin, and 11 prefecture-level cities in Hebei Province, we determined the reasonable prediction model for urban-industrial land after testing the accuracy of the two prediction models. The results showed that the RBF neural network model was the more reasonable prediction model for urban-industrial land. Using the predicted results of the RBF neural network model, combining expected indicators of overall land use plan (2006-2020) in Beijing and Tianjin, as well as 11 prefecture-level cities in Hebei Province in the planning target year, determined remaining usable time of urban-industrial land. Finally, combined with the actual scale of urban-industrial land in 2015 and the predicated scale of urban-industrial land in 2020, the remaining usable time of each city's urban-industrial land was calculated in terms of the average annual growth rate of urban-industrial land from 2009 to 2015. According to the comparative relationship between the remaining usable time and the remaining time of the overall land use plan (5 years), urban-industrial lands were divided into three kinds of regulation zones: reasonable reduction zone, optimized adjustment zone, and core development zone. The policy implications for urban-industrial land in each regulation zone were also provided. This paper can provide reference for regulation zoning of urban-industrial land in developing countries and regions.


Assuntos
Planejamento de Cidades/métodos , Monitoramento Ambiental/métodos , Indústrias/métodos , Política Pública , Pequim , China , Cidades , Modelos Teóricos , População Urbana
6.
J Exp Biol ; 221(Pt 18)2018 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-29997158

RESUMO

Species of the Ostreidae family are key ecosystem engineers and many of them - including Crassostrea gigas and Crassostreavirginica - are commercially important aquaculture species. Despite similarities in their morphology and ecology, these two species differ in their ability to defend against pathogens, potentially reflecting species-specific differential specialization of hemocytes on immune defense versus biomineralization. To test this hypothesis, we investigated the expression levels of immune- and biomineralization-related genes as well as mineralogical and mechanical properties of the shells and the calcium sequestration ability of the hemocytes of C. gigas and C. virginica The expression of biomineralization-related genes was higher in C. virginica than in C. gigas in multiple tissues including the mantle edge and hemocytes, while the expression of immune genes was higher in the hemocytes of C. gigas Hemocytes of C. virginica contained more calcium (stored intracellularly as calcium carbonate mineral) compared with those of C. gigas Analysis of the adult shells showed that the crystallinity of calcite was higher and the laths of the foliated layer of the shell were thicker in C. virginica than in C. gigas Mechanically, the shells of C. virginica were stiffer, harder and stronger than those of C. gigas Taken together, our results show that the species-specific differences in physiology (such as disease resistance and exoskeleton properties) are reflected at the cellular and molecular levels in the differential specialization of hemocytes on potentially competing functions (immunity and biomineralization) as well as different expression profiles of other tissues involved in biomineralization (such as the mantle edge).


Assuntos
Exoesqueleto/fisiologia , Biomineralização/fisiologia , Crassostrea/fisiologia , Hemócitos/imunologia , Imunidade Inata/fisiologia , Transcriptoma/fisiologia , Animais , Biomineralização/imunologia , Crassostrea/genética , Crassostrea/imunologia , Especificidade da Espécie
7.
IEEE Trans Pattern Anal Mach Intell ; 46(2): 681-694, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37463080

RESUMO

Light field disparity estimation is an essential task in computer vision. Currently, supervised learning-based methods have achieved better performance than both unsupervised and optimization-based methods. However, the generalization capacity of supervised methods on real-world data, where no ground truth is available for training, remains limited. In this paper, we argue that unsupervised methods can achieve not only much stronger generalization capacity on real-world data but also more accurate disparity estimation results on synthetic datasets. To fulfill this goal, we present the Occlusion Pattern Aware Loss, named OPAL, which successfully extracts and encodes general occlusion patterns inherent in the light field for calculating the disparity loss. OPAL enables: i) accurate and robust disparity estimation by teaching the network how to handle occlusions effectively and ii) significantly reduced network parameters required for accurate and efficient estimation. We further propose an EPI transformer and a gradient-based refinement module for achieving more accurate and pixel-aligned disparity estimation results. Extensive experiments demonstrate our method not only significantly improves the accuracy compared with SOTA unsupervised methods, but also possesses stronger generalization capacity on real-world data compared with SOTA supervised methods. Last but not least, the network training and inference efficiency are much higher than existing learning-based methods. Our code will be made publicly available.

8.
IEEE Trans Cybern ; PP2024 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-39471118

RESUMO

Intelligent anomaly detection (AD) methods have achieved much successes in machinery condition monitoring. However, the underlying independent and identically distributed assumption restricts their application scopes to steady operating conditions. False and missing alarms would occur when machines operate under time-varying circumstances. In this work, a more challenging time-varying setting is studied, where the working conditions are continuously changing, such that few or no samples are available for model training at one single condition. To tackle this issue, we propose a unified flowing normality learning (UFNL) framework, which aims to capture the flowing normal conditional distribution of time-varying samples and assigns dynamic decision boundary for AD. Specifically, a manifold-based probability density estimation is utilized to guide the adversarial learning process of generative adversarial networks, where adjacent samples are aggregated to approximate the conditional distribution by a conditional generator. Then, a latent normality inversion is proposed to extract the manifold structure from the pretrained generator and to map it into the latent space via a conditional encoder. The reconstruction errors from the encoder and generator can reveal the deviation of signals to the flowing normality. Finally, a condition-aware adaptive threshold selection strategy is proposed, where different thresholds are adaptively assigned for different conditions. Experiments are carried out under two typical continuous time-varying scenarios. The results demonstrate that the proposed framework can realize accurate fault detection at any operating condition within continuously changing environments.

9.
Front Oncol ; 14: 1345737, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38706597

RESUMO

Introduction: Cancer represents a significant global public health concern. In recent years, the incidence of cancer has been on the rise worldwide due to various factors, including diet, environment, and an aging population. Simultaneously, advancements in tumor molecular biology and genomics have led to a shift from systemic chemotherapy focused on disease sites and morphopathology towards precise targeted therapy for driver gene mutations. Therefore, we propose a comprehensive review aimed at exploring the research hotspots and directions in the field of Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutant cancers over the past decade, providing valuable insights for cancer treatment strategies. Specifically, we aim to present an intellectual landscape using data obtained from the Web of Science (WoS) regarding KRAS mutation. Methods: Bibliometrix, VOSviewer, CiteSpace, and HistCite were employed to conduct scientometric analyses on national publications, influential authors, highly cited articles, frequent keywords, etc. Results: A total of 16,609 publications met the screening criteria and exhibited a consistent annual growth trend overall. Among 102 countries/regions, the United States occupied the vast majority share of the published volume. The journal Oncotarget had the highest circulation among all scientific publications. Moreover, the most seminal articles in this field primarily focus on biology and targeted therapies, with overcoming drug resistance being identified as a future research direction. Conclusion: The findings of the thematic analysis indicate that KRAS mutation in lung cancer, the prognosis following B-Raf proto-oncogene, serine/threonine kinase (BRAF) or rat sarcoma (RAS) mutations, and anti-epidermal growth factor receptor (EGFR)-related lung cancer are the significant hotspots in the given field. Considering the significant advancements made in direct targeting drugs like sotorasib, it is anticipated that interest in cancers associated with KRAS mutations will remain steadfast.

10.
Environ Sci Pollut Res Int ; 29(27): 41492-41504, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35089519

RESUMO

The research on land use transformation has attracted more and more attention, and there are few research results on the eco-environmental effects of regional land use change from the perspective of land use function transformation. From the perspective of production-living-ecological land use function classification, this paper obtained land use change data of Shaanxi Province in 2000, 2010, and 2020, calculated the land use transfer matrix, ecological environment quality index, and ecological contribution rate of land use transformation, and quantitatively analyzed the temporal and spatial evolution of production-living-ecological spaces and the eco-environmental effects of land use structure transformation in Shaanxi Province. The results showed that the land use change in Shaanxi Province is mainly manifested in the continuous increase of ecological and living land area and the continuous decrease of production land area from 2000 to 2020. In the transformation of land use structure in Shaanxi Province, the biggest change in area is the mutual transformation between productive cultivated land and ecological grassland land. The occupation of ecological grassland land by other land types is an important factor leading to the decline of ecological environment quality. Overall, the ecological environment of Shaanxi Province has shown a trend of improvement in the past two decades. Quantitative research on the transformation characteristics of land use structure and its ecological environment effects in the past two decades is conducive to providing data support for the promotion of ecological civilization construction in Shaanxi Province.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , China , Clima , Eficiência
11.
ISA Trans ; 107: 224-255, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32854956

RESUMO

Rotating machinery intelligent diagnosis based on deep learning (DL) has gone through tremendous progress, which can help reduce costly breakdowns. However, different datasets and hyper-parameters are recommended to be used, and few open source codes are publicly available, resulting in unfair comparisons and ineffective improvement. To address these issues, we perform a comprehensive evaluation of four models, including multi-layer perception (MLP), auto-encoder (AE), convolutional neural network (CNN), and recurrent neural network (RNN), with seven datasets to provide a benchmark study. We first gather nine publicly available datasets and give a comprehensive benchmark study of DL-based models with two data split strategies, five input formats, three normalization methods, and four augmentation methods. Second, we integrate the whole evaluation codes into a code library and release it to the public for better comparisons. Third, we use specific-designed cases to point out the existing issues, including class imbalance, generalization ability, interpretability, few-shot learning, and model selection. Finally, we release a unified code framework for comparing and testing models fairly and quickly, emphasize the importance of open source codes, provide the baseline accuracy (a lower bound), and discuss existing issues in this field. The code library is available at: https://github.com/ZhaoZhibin/DL-based-Intelligent-Diagnosis-Benchmark.

12.
ACS Biomater Sci Eng ; 6(4): 1950-1964, 2020 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33455316

RESUMO

Magnesium alloys are the most widely studied biodegradable metals for biodegradable vascular stent application. Two major issues with current magnesium alloy based stents are their low ductility and fast corrosion rates. Several studies have validated that introduction of Li into the magnesium alloys will significantly improve the ductility while alloying with Al will improve the corrosion resistance and strength. In the present study, we studied the effects of alloying different amounts of Li and Al on the Mg-Li-Al-Zn (LAZ) quaternary alloy system. Rods were made from four different LAZ alloys, namely, LAZ611, LAZ631, LAZ911, and LAZ931 following melting, casting, and then extrusion. Systematic assessment of mechanical properties, in vitro corrosion, cytotoxicity, and in vivo degradation including local and systemic toxicity conducted demonstrated the beneficial effects of Li and Al on the mechanical properties. Our results specifically suggest that alloying with Li significantly improved the ductility while Al enhanced the strength of the LAZ alloys. Four of the LAZ alloys exhibited different corrosion rates in Hank's balanced salt solution depending on the chemical composition. Indirect in vitro cytotoxicity tests also showed lower cytotoxicity for the alloys exhibiting higher corrosion resistance. In vivo corrosion rates in the mouse subcutaneous model showed different corrosion rates compared to the in vitro tests. Nevertheless, all of the four LAZ alloys displayed no local and systemic toxicity based on the histology analysis. This research study, therefore, demonstrated the benefits of using Li and Al as alloying elements in LAZ alloys and the potential use of LAZ alloys for vascular stent application.


Assuntos
Alumínio , Lítio , Ligas/toxicidade , Alumínio/toxicidade , Animais , Materiais Biocompatíveis/toxicidade , Teste de Materiais , Camundongos , Stents , Zinco/toxicidade
13.
Commun Biol ; 3(1): 787, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33339963

RESUMO

Pediatric laryngotracheal stenosis is a complex congenital or acquired airway injury that may manifest into a potentially life-threatening airway emergency condition. Depending on the severity of obstruction, treatment often requires a combination of endoscopic techniques, open surgical repair, intraluminal stenting, or tracheostomy. A balloon expandable biodegradable airway stent maintaining patency while safely degrading over time may address the complications and morbidity issues of existing treatments providing a less invasive and more effective management technique. Previous studies have focused on implementation of degradable polymeric scaffolds associated with potentially life-threatening pitfalls. The feasibility of an ultra-high ductility magnesium-alloy based biodegradable airway stents was demonstrated for the first time. The stents were highly corrosion resistant under in vitro flow environments, while safely degrading in vivo without affecting growth of the rabbit airway. The metallic matrix and degradation products were well tolerated by the airway tissue without exhibiting any noticeable local or systemic toxicity.


Assuntos
Ligas , Materiais Biocompatíveis , Lítio , Magnésio , Stents , Zinco , Obstrução das Vias Respiratórias/diagnóstico , Obstrução das Vias Respiratórias/terapia , Animais , Biópsia , Criança , Modelos Animais de Doenças , Humanos , Imageamento Tridimensional , Imuno-Histoquímica , Nanotecnologia , Coelhos , Radiografia , Estenose Traqueal/diagnóstico , Estenose Traqueal/terapia , Resultado do Tratamento , Microtomografia por Raio-X
14.
J Mater Chem B ; 8(36): 8476-8477, 2020 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-32902534

RESUMO

Correction for 'Chondroitin sulfate-polydopamine modified polyethylene terephthalate with extracellular matrix-mimetic immunoregulatory functions for osseointegration' by Ya-Min Li et al., J. Mater. Chem. B, 2019, 7, 7756-7770, DOI: 10.1039/C9TB01984G.

15.
J Biomater Appl ; 33(8): 1080-1093, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30717611

RESUMO

Airway obstruction conditions are relatively rarely observed in clinical settings but nevertheless, extremely challenging to handle, especially when observed in pediatric patients. Several surgical procedures, including tracheal resection, end-to-end tracheal anastomosis, and tracheoplasty, have been developed and practised of late, to treat airway obstruction. However, the clinical outcome is typically not satisfactory due to airway restenosis conditions that develop following surgery. Various types of stents are currently available for airway stenting ranging from non-degradable silicone tubes and bio-inert metallic stents (bare or coated with polymer matrix) to hybrid silicone tubes strengthened by metallic cores, but none of the stents provides the satisfactory long-term effectiveness. Therefore, there is a significant clinical need for a biodegradable airway stent that would maintain airway patency and totally degrade over time after meeting the desired objectives. The present study aims to investigate biodegradable magnesium-aluminum-zinc-calcium-manganese (AZXM) alloy as a potential tracheal stent. The new AZXM alloy was fabricated by partially replacing aliminum in commercial AZ31 alloy with calcium. The present study demonstrates that calcium preferentially segregates along the grain boundaries as intermetallic phases (Mg2Ca) and is homogeneously distributed in the magnesium matrix. The extruded AZXM alloy showed less pitting, higher corrosion resistance in Hank's Balanced Salt Solution (HBSS) compared to the as-cast and solution-treated AZXM alloys and exhibited optimized mechanical properties. In vitro cytotoxicity evaluation using human trachea epithelial cells demonstrated excellent cyto-compatibility of AZXM alloys compared to pure Mg and commercial AZ31 validated by a very preliminary rabbit in vivo tracheal model study. Preliminary results show that the approach to use biodegradable AZXM alloys as a tracheal stent is indeed promising, although further alloy processing is required to improve the ductility needed followed by a more exhaustive in vivo study to demonstrate full viability for stent applications.


Assuntos
Implantes Absorvíveis , Ligas/química , Materiais Biocompatíveis/química , Stents , Traqueia/cirurgia , Animais , Cálcio/química , Linhagem Celular , Sobrevivência Celular , Corrosão , Estudos de Viabilidade , Humanos , Manganês/química , Teste de Materiais , Coelhos , Mucosa Respiratória/citologia , Traqueia/citologia
16.
Colloids Surf B Biointerfaces ; 178: 22-31, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30825775

RESUMO

Although bioactive glasses have been traditionally used in the clinical practice for a long period, their uncontrollable architecture and poor mechanical robustness remains a neck bottle for further biomedical applications. In this study, we firstly developed a series of mesoporous bioactive glass (MBG) nanorods with different aspect ratios and adjustable pore sizes via a thermal-mediation approach. The nanorods were then dispersed in MBG sol, followed by impregnation with sponge and in situ gelation. After sinter treatment, the sponge template was removed to offer interconnected macroporous structure, while the intercross-linked MBG nanorods afford meso- and micro- pores. The resulting scaffolds presented a 2-fold reinforcement in compressive strength (1.03 MPa) which is matchable to that of cancellous bone. When their mesopore size was tuned to 7.38 nm, the scaffolds enabled an optimal protein adsorption capacity and sustainable release property. Upon 3-day incubation in simulated body fluid, the scaffolds with macro/meso/micro porous structure present more needle-like hydroxyapatites, indicating their promoted biomineralization capacity. After culture with rat bone marrow stromal cells for 1 day, the hierarchical porous scaffolds displayed good cell attachment and proliferation ability, suggesting their potential as a kind of scaffolds for tissue engineering.


Assuntos
Cerâmica/química , Nanocompostos/química , Nanotubos/química , Alicerces Teciduais/química , Biomineralização , Porosidade , Engenharia Tecidual/métodos
17.
J Biomed Mater Res B Appl Biomater ; 107(6): 1844-1853, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30521126

RESUMO

Tracheal stenting currently using non-degradable stents is commonplace for treatment of trauma, prolonged intubation related adult airway obstructions, and pediatric patients-associated tracheal stenosis conditions. Degradable tracheal stent placement will avoid complications of stent removal and restenosis. Widespread reports exist on degradable magnesium alloys success for orthopedic and cardiovascular applications but none to date for intra tracheal use. This research explores the use of pure Mg, AZ31, and Mg-3Y alloys for degradable tracheal stent assessment. In vitro evaluation of magnesium, prototype stents in a bioreactor simulate the airway environment and corrosion. Micro-CT imaging and biocompatibility evaluation helped assess the 24-week degradation of intraluminal alloy stents following implantation in a rat tracheal in vivo bypass model. Histological analysis indicate tissue response of the harvested stented trachea segments after each time point. Corrosion studies for each alloy indicate significant differences between the simulated and control in vitro conditions. AZ31 exhibited the lowest volume loss of 6.8% in saline, while pure Mg displayed the lowest volume loss of 4.6% in simulated airway fluid (SAF), both at 1-week time points. Significant differences in percentage of total volume lost after 6 months were determined between the alloys over time. MgY alloy displayed the slowest corrosion losing only 15.1% volume after 24 weeks of immersion. Additionally, in vitro magnesium alloy corrosion was not significantly different from the percentage of total volume lost in vivo at 1-week time point. The study demonstrates promise of magnesium alloys for intraluminal tracheal stent application albeit viability of a clinically translatable model warrants further studies. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1844-1853, 2019.


Assuntos
Implantes Absorvíveis , Ligas , Materiais Revestidos Biocompatíveis , Magnésio , Teste de Materiais , Traqueia , Animais , Criança , Feminino , Humanos , Ratos , Ratos Endogâmicos Lew , Traqueia/metabolismo , Traqueia/patologia , Traqueia/cirurgia
18.
J Mater Chem B ; 7(48): 7756-7770, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31750849

RESUMO

Optimal integration between the polyethylene terephthalate (PET) graft and host bone is a prerequisite to obtain a satisfactory outcome after graft implantation for ligament reconstruction. Recent studies indicate that complex biosignals including immunoregulation, cell recruitment, and osteogenic differentiation provided by the extracellular matrix (ECM) are conducive to promoting osseointegration. In the present study, a chondroitin sulfate (CS)/polydopamine-modified PET graft was developed to regulate the local immune microenvironment, guide stem cell behavior, and promote new bone formation. We found that CS-modified PET grafts significantly regulated the macrophage phenotype switching from M1 to M2 and promoted the expression of pro-repair cytokines including interleukin (IL)-4, IL-10 and transforming growth factor (TGF)-ß1. Moreover, the immunoregulatory function of CS-modified PET guided stem cell behaviors, including recruitment, adhesion, and proliferation, and enhanced the osteogenic differentiation of stem cells. In vivo experiments confirmed that CS-modified PET switched the local immune microenvironment status from pro-inflammatory to anti-inflammatory, up-regulated osteogenic marker expression, and promoted the bone regeneration process, so as to achieve graft-bone osseointegration. These results indicate that an ECM-biomimetic immunoregulatory coating is an effective approach to promote graft integration. This study proposes an effective strategy for an artificial graft to achieve graft-bone osseointegration through immunoregulatory osteogenesis.


Assuntos
Biomimética/métodos , Matriz Extracelular/imunologia , Osseointegração , Polietilenotereftalatos/química , Animais , Regeneração Óssea/efeitos dos fármacos , Sulfatos de Condroitina/química , Humanos , Indóis/química , Osseointegração/efeitos dos fármacos , Osteogênese , Polímeros/química , Próteses e Implantes
19.
Environ Sci Pollut Res Int ; 25(15): 15268, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29151183

RESUMO

The original version of this article unfortunately contains mistakes.

20.
ACS Biomater Sci Eng ; 4(3): 919-932, 2018 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33418774

RESUMO

Magnesium alloys have been extensively studied as a novel biodegradable metallic material for cardiovascular stent application. However, the ductility limitation of magnesium alloy has been a key issue for biodegradable stents applications. In this study, two different multiphase ultrahigh ductility Mg-Li-Zn alloys, LZ61 and LZ91, are fabricated in the form of extruded rods and evaluated both in vitro and in vivo. The microstructure, mechanical properties and in vitro degradation are evaluated as well as in vitro cytotoxicity. The in vivo degradation, tissue response, and systematic toxicity are evaluated in a mouse subcutaneous model. Measurements show that LZ61 and LZ91 exhibit more than 40% elongation at fracture without significantly compromising the strength. Both in vitro and in vivo degradation showed low degradation rates for LZ61 but high degradation rate for the LZ91 alloy. Excellent biocompatibility is observed both in vivo and in vitro for LZ61 and LZ91. In summary, this study successfully demonstrates that the ultraductility multiphase Mg-Li-Zn alloy has the potential to be used for stent applications. Compared to LZ91, the LZ61 alloy shows better balance of mechanical properties, corrosion resistance, and biocompatibility, indicating its promise for cardiovascular stent applications.

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