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1.
Am J Primatol ; 86(8): e23636, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38824636

RESUMO

As a central topic in Behavioral Ecology, animal space use involves dynamic responses to social and ecological factors. We collared 22 rhesus macaques (Macaca mulatta) from six groups on Neilingding Island, China, and collected 80,625 hourly fixes over a year. Using this high-resolution location data set, we quantified the macaques' space use at the individual level and tested the ecological constraints model while considering various environmental and human interfering factors. As predicted by the ecological constraints model, macaques in larger groups had longer daily path lengths (DPLs) and larger home ranges. We found an inverted U-shape relationship between mean daily temperatures and DPLs, indicating that macaques traveled farther on mild temperature days, while they decreased DPLs when temperatures were too high or too low. Anthropogenic food subsidies were positively correlated to DPLs, while the effect of rainfall was negative. Macaques decreased their DPLs and core areas when more flowers and less leaves were available, suggesting that macaques shifted their space use patterns to adapt to the seasonal differences in food resources. By applying GPS collars on a large number of individuals living on a small island, we gained valuable insights into within-group exploitation competition in wild rhesus macaques.


Assuntos
Sistemas de Informação Geográfica , Comportamento de Retorno ao Território Vital , Macaca mulatta , Animais , Macaca mulatta/fisiologia , China , Masculino , Feminino , Ecossistema , Temperatura , Estações do Ano , Ilhas
2.
Clin Immunol ; 257: 109811, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37858752

RESUMO

BACKGROUND: To explore the specific marker of CD8+ T cell subsets which are closely related to the prognosis and immunotherapy of patients with colon cancer. METHODS: 18 kinds of immune cell expression profile data sets were obtained from GEO database. Compared with other immune cell types, the specific markers of CD8 (+) T cells (TI-CD8) in colorectal cancer were screened. Regression analyses were used to further screen prognostic related genes and construct a prognostic evaluation model. The patients were stratified and analyzed according to the risk scores, KRAS mutation status, stage, lymphatic infiltration and other indicators. The landscape of infiltration level, mutation and copy number variation of immune subsets in high and low TI-CD8Sig score groups were compared and analyzed. The difference of drug response between high and low TI-CD8Sig score groups was analyzed. Differential expression of the model genes was verified by the HPA database. RESULTS: Six prognostic-related CD8T cell-specific gene targets were further screened, and the prognostic evaluation model was constructed. The AUC value of the model is >0.75. FAT3 and UNC13C showed a high mutation state in the low-risk group, while USH2A, MUC5B et al. specifically showed a high mutation state in the high-risk group. Compared with the low-risk group, the high-risk group had lower effective rate of drug response. The expression of PD-1 gene was positively correlated with the level of TI-CD8Sig score. CONCLUSION: The risk assessment model based on CD8T cell-specific marker genes can effectively predict the prognosis and the drug response of patients with CRC.


Assuntos
Neoplasias do Colo , Variações do Número de Cópias de DNA , Humanos , Neoplasias do Colo/genética , Neoplasias do Colo/terapia , Linfócitos T CD8-Positivos , Prognóstico , Imunoterapia , Aprendizado de Máquina , Microambiente Tumoral
3.
Analyst ; 148(17): 4148-4155, 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37498542

RESUMO

Rapid screening platforms for antibiotic susceptibility testing (AST) are important in inhibiting bacterial resistance in clinical practice. Herein, a rapid screening platform is reported for AST, which is based on nanofiber membrane enrichment bacteria-assisted cell counting Kit-8 (CCK8) colorimetry. The absorbance of CCK8 formazan has a linear relationship with the number of bacteria. The interference of antibiotics in the absorbance of CCK8 formazan could be eliminated by separating planktonic bacteria from the culture medium using nanofiber membranes. The total detection time is 7-9 h, using the new screening platform, which is significantly shorter than that with the traditional method, and the limit of detection of this method is 10 CFU mL-1. The evaluation results of antibiotic susceptibility are identical when using the new screening method and traditional methods. This method meets the definition of "rapid testing" for antibiotic susceptibility by most microbiologists. Furthermore, the new screening platform for antibiotic susceptibility testing ability in vitro was proved using E. coli in urine and blood, and S. aureus in wound fluid as practical samples. All the results showed that the new screening platform is a promising method for rapid antibiotic susceptibility testing in vitro.


Assuntos
Colorimetria , Staphylococcus aureus , Escherichia coli , Testes de Sensibilidade Microbiana , Formazans , Antibacterianos/farmacologia , Bactérias
4.
Zhongguo Zhong Yao Za Zhi ; 48(15): 4231-4236, 2023 Aug.
Artigo em Zh | MEDLINE | ID: mdl-37802791

RESUMO

Traditional Chinese medicine(TCM) formula granules are highly praised for the advanced, convenient, and modern use of Chinese medicinal materials. The safety of TCM formula granules has long been a concern of regulatory authorities and the medical industry. A multi-center, prospective, open, non-interventional, and centralized monitoring was carried out for the patients treated with TCM formula granules in 252 medical institutions from February 5, 2020 to April 19, 2022. All the case data and the incidence of adverse drug reactions/events were recorded. This study evaluated the safety of TCM formula granules, aiming to provide a reference for the clinically use. A total of 20 547 patients were included in this study. Four adverse events were recorded, including 3 adverse drug reactions with an adverse drug reaction rate of 0.015%, all of which occurred in the digestive system. There was no serious adverse event, and no factors related to adverse drug reactions/events were identified. The incidence of adverse drug reactions/events associated with China Resources Sanjiu Medical & Pharmaceutical Co., Ltd. TCM formula granules was rare, which proved their safety in clinical use. A comprehensive data mining and objective analysis was carried out for the medicines with high frequency in TCM formula granules, the commonly used medicine pairs and combinations, and departmental medication. The drug use characteristics, prescription rules, and departmental use of TCM formula granules were summarized, which can shed light on the prescription compatibility and clinical application.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Medicamentos de Ervas Chinesas , Humanos , Medicina Tradicional Chinesa/efeitos adversos , Medicamentos de Ervas Chinesas/efeitos adversos , Estudos Prospectivos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , China
5.
Sensors (Basel) ; 22(22)2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36433239

RESUMO

We propose a robust RGB-Depth (RGB-D) Visual Odometry (VO) system to improve the localization performance of indoor scenes by using geometric features, including point and line features. Previous VO/Simultaneous Localization and Mapping (SLAM) algorithms estimate the low-drift camera poses with the Manhattan World (MW)/Atlanta World (AW) assumption, which limits the applications of such systems. In this paper, we divide the indoor environments into two different scenes: MW and non-MW scenes. The Manhattan scenes are modeled as a Mixture of Manhattan Frames, in which each Manhattan Frame in itself defines a Manhattan World of a specific orientation. Moreover, we provide a method to detect Manhattan Frames (MFs) using the dominant directions extracted from the parallel lines. Our approach is designed with lower computational complexity than existing techniques using planes to detect Manhattan Frame (MF). For MW scenes, we separately estimate rotational and translational motion. A novel method is proposed to estimate the drift-free rotation using MF observations, unit direction vectors of lines, and surface normal vectors. Then, the translation part is recovered from point-line tracking. In non-MW scenes, the tracked and matched dominant directions are combined with the point and line features to estimate the full 6 degree of freedom (DoF) camera poses. Additionally, we exploit the rotation constraints generated from the multi-view dominant directions observations. The constraints are combined with the reprojection errors of points and lines to refine the camera pose through local map bundle adjustment. Evaluations on both synthesized and real-world datasets demonstrate that our approach outperforms state-of-the-art methods. On synthesized datasets, average localization accuracy is 1.5 cm, which is equivalent to state-of-the-art methods. On real-world datasets, the average localization accuracy is 1.7 cm, which outperforms the state-of-the-art methods by 43%. Our time consumption is reduced by 36%.


Assuntos
Algoritmos
6.
Mol Cancer ; 20(1): 104, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34412644

RESUMO

Circulating tumor cells are tumor cells with high vitality and high metastatic potential that invade and shed into the peripheral blood from primary solid tumors or metastatic foci. Due to the heterogeneity of tumors, it is difficult for high-throughput sequencing analysis of tumor tissues to find the genomic characteristics of low-abundance tumor stem cells. Single-cell sequencing of circulating tumor cells avoids interference from tumor heterogeneity by comparing the differences between single-cell genomes, transcriptomes, and epigenetic groups among circulating tumor cells, primary and metastatic tumors, and metastatic lymph nodes in patients' peripheral blood, providing a new perspective for understanding the biological process of tumors. This article describes the identification, biological characteristics, and single-cell genome-wide variation in circulating tumor cells and summarizes the application of single-cell sequencing technology to tumor typing, metastasis analysis, progression detection, and adjuvant therapy.


Assuntos
Biomarcadores Tumorais , Sequenciamento de Nucleotídeos em Larga Escala , Neoplasias/diagnóstico , Neoplasias/genética , Células Neoplásicas Circulantes/metabolismo , Análise de Célula Única , Citometria de Fluxo , Perfilação da Expressão Gênica , Heterogeneidade Genética , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Neoplasias/terapia , Células-Tronco Neoplásicas/metabolismo , Análise de Célula Única/métodos , Transcriptoma
7.
J Pediatr Nurs ; 53: 6-13, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32299035

RESUMO

BACKGROUND: Extensive research on the link between the organizational characteristics of the work environment and patient safety in a healthcare organization has been conducted; yet, only a few studies have concentrated on care providers in a pediatric unit. OBJECTIVES: To determine the correlation between different work environment factors impacting patient safety in a pediatric care unit from the perspective of registered nurses working in these units. DESIGN: Cross-sectional design. DATA SOURCES AND METHODS: The study was conducted with 155 registered nurses from a pediatric unit in a medical center in Taiwan with the Chinese version of the Safety Attitudes Questionnaire (SAQ) 2014-2017. RESULTS: Teamwork climate, higher job satisfaction, and better working conditions are linked to positive perceptions of patient safety culture. Emotional exhaustion is negatively related to most dimensions of patient safety. CONCLUSION: Teamwork climate, job satisfaction, working conditions, and emotional exhaustion were identified as critical factors impacting the patient safety climate. IMPLICATIONS FOR NURSING OR HEALTH POLICY: Investments to improve teamwork climate, job satisfaction, and working conditions and reduce emotional exhaustion may have a positive effect on patient safety in pediatric care units.


Assuntos
Cultura Organizacional , Segurança do Paciente , Atitude do Pessoal de Saúde , Criança , Estudos Transversais , Pessoal de Saúde , Humanos , Satisfação no Emprego , Percepção , Gestão da Segurança , Inquéritos e Questionários , Taiwan
8.
Chemistry ; 25(30): 7280-7284, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-30946487

RESUMO

Diindeno-fused dibenzo[a,h]anthracene 6 and diindeno-fused dibenzo[c,l]chrysene 9 contain the key moieties 1,4-quinodipropene (1,4-QDP) and 2,6-naphthoquinodipropene (2,6-NQDP), respectively, and they both have an open-shell singlet ground state. The latter compound exhibits a strong biradical character and interesting properties, including a low ΔET-S (2.44 kcal mol-1 ), a small HOMO-LUMO gap (1.06 eV), a wide photoabsorption range (250-1172 nm), and a large two-photon absorption cross-section (σ=1342±56 GM). This work verifies that 6 has a slightly larger HOMO-LUMO gap and ΔET-S than its helical isomer diindeno[2,1-f:1',2'-j]picene (DIP), but is a much stronger two-photon absorber, verifying the important effect of geometry on the photophysical properties.

9.
J Am Chem Soc ; 140(43): 14357-14366, 2018 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-30346739

RESUMO

5,14-Diaryldiindeno[2,1- f:1',2' -j]picene (DDP, 1), a thermally and chemically stable helical arene, can be prepared from 1,4-bis[2-(arylethynyl)phenyl]benzene in four synthetic steps. Its helical backbone, which incorporates an o-quinodimethane moiety, was verified by X-ray crystallography, and this structural feature results in a very high barrier to racemization (exceeding 50 kcal/mol). DDP possesses versatile and promising properties, including a small HOMO-LUMO energy gap (1.31 eV for the dimesityl-substituted derivative 1ab), an electron spin resonance (ESR)-active character, a small triplet-singlet energy gap (4.75 kcal/mol), broad photoabsorption covering the ultraviolet, visible, and near-infrared (NIR) regions, two-photon absorption in the NIR range, and respectable ambipolar charge-transport behavior in a solution-processed organic field-effect transistor.

10.
Soft Matter ; 14(21): 4231-4237, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29624193

RESUMO

3-Hydroxyflavone derivatives have great potential as fluorescent probes for bio-labeling in aqueous medium. They were extensively studied in various organic solvents for the "excited state intramolecular proton transfer" process, but seldom addressed in aqueous solution due to the poor water solubility. Herein, an amphiphilic molecule bearing 3-hydroxyflavone and oligo(ethylene oxide) (denoted as 3HF-EO) was designed and synthesized. Different from the fluorescence in organic solvents, 3HF-EO in aqueous solution showed a remarkable single fluorescence emission, which is ascribed to the fluorescence of its anionic species. We found that the fluorescence intensity could be efficiently tuned via host-guest complexation. α-CD has little effect on the emission, while ß-CD and γ-CD lead to enhanced and reduced emissions of 3HF-EO, respectively. The 1H NMR and 2D NOESY NMR spectra indicate that α-CD barely had any interaction with 3HF-EO, while ß-CD and γ-CD formed complexes with one and two 3HF-EO molecules, respectively. These results provide a sound explanation for the modulated fluorescence intensity.

11.
Soft Matter ; 14(21): 4374-4379, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29767187

RESUMO

Here, we report separately enhanced dual emissions of the amphiphilic derivative of 2-(2'-hydroxyphenyl)benzothiazole (denoted as HBT-11) by supramolecular complexation with cyclodextrins (CDs). When dispersed in water, HBT-11 shows two relatively weak emission bands, which can be assigned to the emissions of enol- and keto-forms, the two tautomers, owing to excited-state intramolecular proton transfers. Upon the addition of α-CD and ß-CD, the keto- and enol-emissions, respectively, are separately enhanced; the enhancement effect is due to the formation of HBT-11/α-CD and HBT-11/ß-CD complexes through multiple hydrogen bonding and host-guest interactions, respectively. It is worth to note that the keto-emission caused by the complex of HBT-11/α-CD has a much shorter wavelength compared with that of the aggregates formed by pure HBT-11. To the best of our knowledge, this is the first time that a study on keto-emission of the isolated HBT chromophore has been reported.

12.
Am J Primatol ; 80(2)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29266298

RESUMO

The social relationships that individuals experience at different life stages have a non-negligible influence on their lives, and this is particularly true for group living animals. The long lifespan of many primates makes it likely that these animals have various tactics of social interaction to adapt to complex changes in environmental or physical conditions. The different strategies used in social interaction by individuals at different life stages, and whether the position (central or peripheral) or role (initiator or recipient) of an individual in the group social network changes with age, are intriguing questions that remain to be investigated. We used social network analysis to examine age-related differences in social interaction patterns, social roles, and social positions in three affiliative social networks (approach, allogrooming, and social play) in a group of wild rhesus macaques (Macaca mulatta). Our results showed that social interaction patterns of rhesus macaques differ between age classes in the following ways: i) young individuals tend to allocate social time to a high number of groupmates, older individuals prefer to focus on fewer, specific partners; ii) as they grow older, individuals tend to be recipients in approach interactions and initiators in grooming interactions; and iii) regardless of the different social interaction strategies, individuals of all ages occupy a central position in the group. These results reveal a possible key role played by immature individuals in group social communication, a little-explored issue which deserves closer investigation in future research.


Assuntos
Fatores Etários , Macaca mulatta/psicologia , Comportamento Social , Animais , China , Asseio Animal , Predomínio Social
13.
Am J Primatol ; 80(7): e22881, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29923328

RESUMO

In the present study, we compared mother-infant relationships in 57 mother-infant dyads residing in two wild, semi-provisioned (22 mother-infant dyads in 2014, 35 dyads in 2015) groups of rhesus macaques (Macaca mulatta) in the Nanwan Nature Reserve for Rhesus Macaques, Hainan, China. We also compared reproductive success between these two groups. The ecology and provisioning regime for each group was similar. These groups differed however, in size. Group 1 contained ∼35 individuals and Group 2 contained ∼120 individuals. Data were collected over a 2-year period (2014-2015). We found that during the birth season, mother-infant relationships in the larger group were characterized by less time in contact and more time separated than in the smaller group. Mothers in the smaller group initiated more contact and proximity with their infants. During the mating season when infants were approximately 6 months old, mother-infant relationships in the smaller group were more rejecting. We also found that birth rates were significantly higher but infant survivorship (to 1-year-old) was significantly lower in the smaller group. Moreover, higher-ranking mothers in the larger group were characterized by a higher reproductive output than females of lower rank. In the smaller group, female rank did not affect reproductive output. There was, however, no clear relationship between infant survivorship and maternal rank. We hypothesize that differences in reproductive success and changes in mother-infant relationships between the birth and mating seasons reflect differences in the costs and benefits of group size: females in the larger group faced (i) higher intragroup feeding competition leading to a reduction in birth rate but also (ii) lower predation risk, resulting in higher infant survival rate compared to females in the smaller group. The results of this study point to the tradeoffs that primate females face in living in smaller and larger social groups.


Assuntos
Macaca mulatta/fisiologia , Reprodução/fisiologia , Predomínio Social , Animais , Comportamento Animal/fisiologia , Coeficiente de Natalidade , China , Feminino , Masculino , Mortalidade , Comportamento Social
15.
Am J Primatol ; 78(6): 679-98, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26848718

RESUMO

The rhesus macaque (Macaca mulatta) is the most widely distributed nonhuman primate species in the world, with six subspecies distributed through China. From 2012 to 2014, we conducted studies on the body mass and morphological variation of the southernmost subspecies M. m. brevicaudus in Nanwan Nature Reserve for Rhesus Macaque, Hainan, China. We compared measurements with other populations of this species. We also investigated the inter-group body mass variation from seven provisioned free-ranging groups in our study site. Our results show that M. m. brevicaudus has the smallest body size, the smallest body mass, and the shortest tail among rhesus macaque subspecies. Its sexual dimorphism score is also among the lowest, which is similar to other southern distributed subspecies in China, but smaller than northern distributed subspecies. We found that the average body mass of female macaques is not correlated with their dominance ranks. There are significant differences in body mass among the seven adjacent study groups at the same site, suggesting the existence of inter-group competition. Average body mass of a group is better described by a quadratic function of group size than a linear one as predicted by the socio-ecological model. Am. J. Primatol. 78:679-698, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Macaca mulatta , Predomínio Social , Distribuição Animal , Animais , Tamanho Corporal , China , Feminino , Masculino
16.
Molecules ; 21(6)2016 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-27248989

RESUMO

Polysaccharide (DOPA) from the stem of D. officinale, as well as two fractions (DOPA-1 and DOPA-2) of it, were isolated and purified by DEAE cellulose-52 and Sephacryl S-300 chromatography, and their structural characteristics and bioactivities were investigated. The average molecular weights of DOPA-1 and DOPA-2 were 394 kDa and 362 kDa, respectively. They were mainly composed of d-mannose, d-glucose, and had a backbone consisting of 1,4-linked ß-d-Manp and 1,4-linked ß-d-Glcp with O-acetyl groups. Bioactivity studies indicated that both DOPA and its purified fractions (DOPA-1 and DOPA-2) could activate splenocytes and macrophages. The D. officinale polysaccharides had stimulatory effects on splenocytes, T-lymphocytes and B-lymphocytes, promoting the cell viability and NO production of RAW 264.7 macrophages. Furthermore, DOPA, DOPA-1 and DOPA-2 were found to protect RAW 264.7 macrophages against hydrogen peroxide (H2O2)-induced oxidative injury by promoting cell viability, suppressing apoptosis and ameliorating oxidative lesions. These results suggested that D. officinale polysaccharides possessed antioxidant activity and mild immunostimulatory activity.


Assuntos
Dendrobium/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Animais , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Cromatografia em Gel , Cromatografia Gasosa-Espectrometria de Massas , Peróxido de Hidrogênio/farmacologia , Fatores Imunológicos/química , Fatores Imunológicos/isolamento & purificação , Fatores Imunológicos/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Espectroscopia de Ressonância Magnética , Masculino , Metilação , Camundongos , Peso Molecular , Óxido Nítrico/biossíntese , Extratos Vegetais/isolamento & purificação , Polissacarídeos/isolamento & purificação , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Environ Sci Pollut Res Int ; 30(45): 100994-101013, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37642910

RESUMO

The National Innovative City Pilot Policy (NICPP) is a policy implemented by the Chinese government to create an environment conducive to innovation, optimize industrial structure, promote economic development, and stimulate green innovation. The impact of this policy on ecological welfare performance is a question worth exploring. Based on panel data from 285 cities from 2007 to 2021, this paper uses the multi-period difference-in-difference (DID) model, propensity score matching method, and spatial DID model to study the impact of NICPP on ecological welfare performance and spatial spillover effects. The results show that (1) NICPP can significantly improve ecological welfare performance. (2) The mechanism analysis found that NICPP mainly improves ecological welfare performance through technological innovation investment, industrial structure upgrading, and increasing government attention. (3) The heterogeneity analysis found that NICPP has a more substantial driving effect on the ecological welfare development of cities in the eastern and western regions, cities with higher administrative levels, and cities with lower secondary industry agglomeration. (4) Further research has found that NICPP not only promotes the development of local ecological welfare but also has a positive spatial spillover effect on the ecological welfare performance of neighboring regions. This paper enriches the research on the effects of NICPP and provides policy references for the sustainable development of cities.


Assuntos
Desenvolvimento Econômico , China , Cidades , Políticas
18.
Materials (Basel) ; 16(20)2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37895677

RESUMO

To further explore the quasi-static mechanical characteristics of composite solid propellants at low strain rates, an investigation was conducted on the mechanical behavior and damage mechanisms of a four-component hydroxy-terminated polybutadiene (HTPB) propellant by means of experiments and numerical simulation. A uniaxial tensile test and scanning electron microscope (SEM) characterization experiment were carried out. A microstructural model, which accurately represents the mesoscopic structure, was developed via the integration of micro-CT scanning and image-processing techniques. The constructed microstructural model was utilized to conduct a numerical simulation of the mechanical behavior. The experimental results demonstrated that the maximum tensile strength increases with increasing strain rate, and the primary cause of propellant failure at low strain rates is the dewetting phenomenon occurring at the interface between the larger particles and the matrix. The maximum tensile strength is 0.48 MPa when the strain rate is 0.00119 s-1, and the maximum tensile strength is 0.37 MPa when the strain rate is 0.000119 s-1. The simulation results indicated a consistent trend in variation when comparing the simulation and experimental curves. This suggested that the established model exhibits a high level of reliability, and provides a promising approach for carrying out microstructural simulations of heterogeneous propellants in future. The mechanical behavior of the propellant can be effectively described by utilizing a mesoscopic finite element model that incorporates the superelastic constitutive model of the matrix and the bilinear cohesive model. This framework facilitates the representation of mesoscopic damage evolution, which consequently provides insights into the damage mechanism. Additionally, the utilization of such models assists in compensating for the limitations of damage evolution characterization experiments.

19.
J Mater Chem B ; 11(23): 5043-5050, 2023 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-37211877

RESUMO

The diseases caused by two pathological processes, thrombosis, and thromboembolism, are clinically known as thrombotic diseases, which seriously threaten human life and health, and their incidence rate is the highest among various diseases. Research on thrombotic diseases is one of the focuses and hotspots of contemporary medical research. Nanomedicine is a new branch of nanotechnology used in the medical field, and nanomaterials are widely used in medical imaging and drug delivery to help diagnose and treat major diseases such as cancer. With the gradual maturity of nanotechnology, new nanomaterials have recently been used in antithrombotic drugs and released accurately at lesions, which has improved antithrombotic therapy safety. Nanosystems can be employed for cardiovascular diagnosis in future as they can aid in diagnosing pathological diseases and treat them with targeted delivery systems. Unlike other reviews, we herein aim to illustrate the progress of nanosystems in thrombosis therapy. This paper mainly describes how a drug-loaded nanosystem can control drug release under various conditions and accurately treat thrombus, summarizing the research progress of nanotechnology in antithrombotic therapy so that clinicians can better understand nanotechnology and its applications and provide new ideas for treating thrombosis.


Assuntos
Fibrinolíticos , Trombose , Humanos , Fibrinolíticos/uso terapêutico , Nanotecnologia/métodos , Nanomedicina/métodos , Sistemas de Liberação de Medicamentos/métodos , Preparações Farmacêuticas , Trombose/diagnóstico por imagem , Trombose/tratamento farmacológico
20.
Polymers (Basel) ; 15(19)2023 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-37835918

RESUMO

To study the mechanical properties of highly filled hydroxy-terminated polybutadiene (HTPB) propellant with 90 wt% solid fillers, the stress-strain curves of the propellant under different temperatures (-50 to 70 °C) and strain rates (0.000476 to 0.119048 s-1) were obtained by uniaxial tensile test. Moreover, to obtain the glass transition temperature and understand the effect of low temperatures on the mechanical properties of the propellant, DMA experiments were carried out. On this basis, the mechanical response laws of the propellant were analyzed, and the master curves of mechanical properties were established. Furthermore, the fracture features of the propellant under typical loading conditions were obtained by SEM, and the corresponding failure mechanisms were analyzed. The results show that the maximum strength decreases with increasing temperature, while the maximum elongation increases with increasing temperature at the same strain rate. The maximum tensile strength increases with increasing strain rate, while the maximum elongation decreases with increasing strain rate at the same temperature. The maximum tensile strength is lowest with a value of 0.35 MPa when the temperature is 343.15 K and the strain rate is 0.000476 s-1, at which time the maximum elongation reaches the highest with a value of 44%. In terms of failure mechanisms, the propellant shows no particle fracture, and the failure modes of the propellant are mainly matrix tearing and dewetting.

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