Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Chemistry ; 29(5): e202202811, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36321591

RESUMO

A solvothermal method to prepare PtNi alloys that have differing morphologies is described. By adjusting the feed ratio of Pt and Ni precursors in this process, PtNi alloys with different compositions (Pt : Ni atomic ratio from 1 : 3 to 3 : 1) and morphologies (evolution from nanobranches to nanoparticles) are generated. The prepared Pt48 Ni52 alloy, which has a composite morphology comprised of nanobranches and nanoparticles, exhibits superior activity and durability towards the hydrogen evolution reaction (HER) in seawater compared to those of commercial Pt/C catalyst and other PtNi alloys that have different compositions and morphologies. The excellent seawater HER performance of Pt48 Ni52 is ascribed to its nanobranch/nanoparticle morphology that optimally facilitates electron accumulation on Pt, which enhances resistance to chloride corrosion in seawater.


Assuntos
Ligas , Cloretos , Corrosão , Halogênios , Hidrogênio , Água do Mar
2.
J Liposome Res ; 33(2): 144-153, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35875973

RESUMO

OBJECTIVE: To investigate the preparation of novel nanoliposomes (Borneol Angelica Polysaccharide Liposomes, BAPL) for anti-cerebral ischaemia and verify its curative effects and mechanism. METHODS: By applying a uniform experiment design to investigate the fitting combination of BAPL. Encapsulation Efficiency Evaluation of BAPL Preparation; Particle Size and Surface Potential Evaluation of BAPL Biological activity; Cerebral ischaemia models of rats Evaluation of BAPL curative effects and mechanism. RESULTS: (1) The fitting combination of lecithin, Cholesterol, AP mass and the borneol mass was 60 mg, 60 mg, 45 mg and 5 mg. the highest encapsulation efficiency was 80.4%, the particle size was 179.1 nm, and the surface zeta potential was -17.2 mV. It conforms to the nano-material standards. (2) The results of animal experiments show that: In the BAPL group, the infarct volume of TTC staining was significantly decreased, and the expression levels of NF-κBp65, TLR-4, IL-8, IL-6, IL-1ß in brain tissue were significantly decreased, while the expression levels of ZO-1, ZO-2, IL-10 were significantly increased after cerebral ischaemia-reperfusion. CONCLUSION: BAPL is a novel nano and effective material for anti-cerebral ischaemia.


Assuntos
Isquemia Encefálica , Lipossomos , Ratos , Animais , Isquemia Encefálica/tratamento farmacológico , Isquemia , Polissacarídeos/farmacologia
3.
Cochrane Database Syst Rev ; 5: CD009858, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-33998662

RESUMO

BACKGROUND: The effective control of moisture and microbes is necessary for the success of restoration procedures. The rubber dam, as an isolation method, has been widely used in dental restorative treatments. The effects of rubber dam usage on the longevity and quality of dental restorations still require evidence-based discussion. This review compares the effects of rubber dam with other isolation methods in dental restorative treatments. This is an update of the Cochrane Review first published in 2016. OBJECTIVES: To assess the effects of rubber dam isolation compared with other types of isolation used for direct and indirect restorative treatments in dental patients. SEARCH METHODS: Cochrane Oral Health's Information specialist searched the following electronic databases: Cochrane Oral Health's Trials Register (searched 13 January 2021), Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 12) in the Cochrane Library (searched 13 January 2021), MEDLINE Ovid (1946 to 13 January 2021), Embase Ovid (1980 to 13 January 2021), LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 13 January 2021), and SciELO BIREME Virtual Health Library (1998 to 13 January 2021). We also searched Chinese BioMedical Literature Database (CBM, in Chinese) (1978 to 13 January 2021), VIP database (in Chinese) (1989 to 13 January 2021), and China National Knowledge Infrastructure (CNKI, in Chinese) (1994 to 13 January 2021). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform, OpenGrey, and Sciencepaper Online (in Chinese) for ongoing trials. There were no restrictions on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: We included randomised controlled trials (including split-mouth trials) over one month in length assessing the effects of rubber dam compared with alternative isolation methods for dental restorative treatments. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the results of the electronic searches, extracted data, and assessed the risk of bias of the included studies. Disagreement was resolved by discussion. We strictly followed Cochrane's statistical guidelines and assessed the certainty of the evidence using GRADE. MAIN RESULTS: We included six studies conducted worldwide between 2010 and 2015 involving a total of 1342 participants (of which 233 participants were lost to follow-up). All the included studies were at high risk of bias. Five studies compared rubber dam with traditional cotton rolls isolation. One study was excluded from the analysis due to inconsistencies in the presented data. Of the four remaining trials, three reported survival rates of the restorations with a minimum follow-up of six months. Pooled results from two studies involving 192 participants indicated that the use of rubber dam isolation may increase the survival rates of direct composite restorations of non-carious cervical lesions (NCCLs) at six months (odds ratio (OR) 2.29, 95% confidence interval (CI) 1.05 to 4.99; low-certainty evidence). However, the use of rubber dam in NCCLs composite restorations may have little to no effect on the survival rates of the restorations compared to cotton rolls at 12 months (OR 1.38, 95% CI 0.45 to 4.28; 1 study, 30 participants; very low-certainty evidence) and at 18 months (OR 1.00, 95% CI 0.45 to 2.25; 1 study, 30 participants; very low-certainty evidence) but the evidence is very uncertain. At 24 months, the use of rubber dam may decrease the risk of failure of the restorations in children undergoing proximal atraumatic restorative treatment in primary molars but the evidence is very uncertain (hazard ratio (HR) 0.80, 95% CI 0.66 to 0.97; 1 study, 559 participants; very low-certainty evidence). None of the included studies mentioned adverse effects or reported the direct cost of the treatment. AUTHORS' CONCLUSIONS: This review found some low-certainty evidence that the use of rubber dam in dental direct restorative treatments may lead to a lower failure rate of the restorations compared with cotton roll usage after six months. At other time points, the evidence is very uncertain. Further high-quality research evaluating the effects of rubber dam usage on different types of restorative treatments is required.


Assuntos
Tratamento Dentário Restaurador sem Trauma/instrumentação , Diques de Borracha , Viés , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
4.
J Periodontal Res ; 55(5): 581-593, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32583879

RESUMO

Periodontal disease (PD), as a chronic bacterial infection, might cause cardiovascular and some other systemic diseases, with recent studies reporting that it exhibits some connection with lung cancer. While studies have shown that poor oral health might increase the risk of lung cancer, the veracity of these reports is questionable. Therefore, this meta-analysis was undertaken to investigate the association between PD and the risk of lung cancer. A search was run in PubMed, EMBASE, MEDLINE, CENTRAL, and ClinicalTrials.gov databases up to January 1, 2020. Cohort and case-control studies investigating the correlation between PD and lung cancer were included. Eligibility assessment and data extraction were conducted independently, and a meta-analysis was performed to synthesize the data. The association between PD, edentulism, and lung cancer was measured by the adjusted hazard ratios (HRs) or odds ratios (ORs) and their 95% confidence intervals (CIs) provided in articles. We employed appropriate effect model in terms of I2 (a fixed-effect model for PD and a random-effect model for edentulism) to obtain summary effect estimates. Statistical heterogeneity was investigated by chi-square test and I2 statistics. Newcastle-Ottawa Scale (NOS) was used to assess the quality of their method. Six cohort studies (eight references) and two case-control studies, assessed as high-quality, involving 167 256 participants, were included in the review. The summary estimates based on adjusted data showed an association between PD and a significant risk of lung cancer both in cohort studies (HR = 1.40, 95% CI = 1.25-1.58; I2  = 8.7%) and case-control studies (OR = 1.51, 95% CI = 1.16-1.98; I2  = 36.5%). Similar features were found in the sensitivity analysis and subgroups for six cohort studies, of male only (HR = 1.36, 95% CI = 1.15-2.60), setting the lung cancer incidence as endpoint (HR = 1.39, 95% CI = 1.24-1.57; I2  = 23.9%), and adjusting alcohol for multifactorial HR (HR = 1.38, 95% CI = 1.21-1.57; I2  = 39.9%). The summary HR for edentulism was 1.93 (95% CI = 1.05-3.57; I2  = 55.3%). No obvious publication bias was detected. This systematic review and meta-analysis demonstrated a significant association between PD and the incidence of lung cancer. Further observational studies are required by using standardized measurements to assess the periodontal status and by eliminating confounding factors, such as alcohol and diabetes, to verify such a relationship.


Assuntos
Neoplasias Pulmonares , Doenças Periodontais , Estudos de Casos e Controles , Estudos de Coortes , Humanos , Incidência , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/etiologia , Masculino , Doenças Periodontais/complicações , Doenças Periodontais/epidemiologia
5.
Chem Soc Rev ; 45(12): 3479-563, 2016 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-27255561

RESUMO

Over the last decade, significant effort has been devoted to the applications of hierarchically structured porous materials owing to their outstanding properties such as high surface area, excellent accessibility to active sites, and enhanced mass transport and diffusion. The hierarchy of porosity, structural, morphological and component levels in these materials is key for their high performance in all kinds of applications. The introduction of hierarchical porosity into materials has led to a significant improvement in the performance of materials. Herein, recent progress in the applications of hierarchically structured porous materials from energy conversion and storage, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine is reviewed. Their potential future applications are also highlighted. We particularly dwell on the relationship between hierarchically porous structures and properties, with examples of each type of hierarchically structured porous material according to its chemical composition and physical characteristics. The present review aims to open up a new avenue to guide the readers to quickly obtain in-depth knowledge of applications of hierarchically porous materials and to have a good idea about selecting and designing suitable hierarchically porous materials for a specific application. In addition to focusing on the applications of hierarchically porous materials, this comprehensive review could stimulate researchers to synthesize new advanced hierarchically porous solids.


Assuntos
Materiais Biocompatíveis , Fontes Geradoras de Energia , Processos Fotoquímicos , Adsorção , Materiais Biocompatíveis/química , Catálise , Porosidade
6.
Bioconjug Chem ; 27(3): 762-71, 2016 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-26848507

RESUMO

Considering the systemic toxicity of chemotherapeutic agents, there is an urgent need to develop new targeted drug delivery systems. Herein, we have developed a new nuclear targeted, redox sensitive, drug delivery vehicle to simultaneously deliver the anticancer drugs gemcitabine and doxorubicin to the nuclei of pancreatic cancer cells. We prepared polymeric bilayer vesicles (polymersomes), and actively encapsulated the drug combination by the pH gradient method. A redox-sensitive polymer (PEG-S-S-PLA) was incorporated to sensitize the formulation to reducing agent concentration. Acridine orange (AO) was conjugated to the surface of the polymersomes imparting nuclear localizing property. The polymersomes' toxicity and efficacy were compared with those of a free drug combination using monolayer and three-dimensional spheroid cultures of pancreatic cancer cells. We observed that the redox sensitive, nuclear-targeted polymersomes released more than 60% of their encapsulated contents in response to 50 mM glutathione. The nanoparticles are nontoxic; however, the drug encapsulated vesicles have significant toxicity. The prepared formulation can increase the drug's therapeutic index by delivering the drugs directly to the cells' nuclei, one of the key organelles in the cells. This study is likely to initiate research in targeted nuclear delivery using other drug formulations in other types of cancers.


Assuntos
Laranja de Acridina/química , Antineoplásicos/administração & dosagem , Núcleo Celular/metabolismo , Desoxicitidina/análogos & derivados , Doxorrubicina/administração & dosagem , Neoplasias Pancreáticas/patologia , Polímeros/química , Linhagem Celular Tumoral , Desoxicitidina/administração & dosagem , Humanos , Microscopia Eletrônica de Transmissão , Gencitabina
7.
Small ; 11(17): 2003-10, 2015 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-25641812

RESUMO

An individual cyanobacterium cell is interfaced with a nanoporous biohybrid layer within a mesoporous silica layer. The bio-interface acts as an egg membrane for cell protection and growth of outer shell. The resulting bilayer shell provides efficient functions to create a single cell photosynthetic bioreactor with high stability, reusability, and activity.


Assuntos
Reatores Biológicos , Cianobactérias/metabolismo , Nanoconchas/química , Fotossíntese , Materiais Biocompatíveis/química , Biomassa , Dióxido de Carbono/química , Cisteína/química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanotecnologia/métodos , Transição de Fase , Porosidade , Silício , Dióxido de Silício , Energia Solar , Propriedades de Superfície , Synechococcus , Raios Ultravioleta
8.
Mol Pharm ; 11(1): 158-63, 2014 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-24266549

RESUMO

Pegylation of therapeutic proteins is an established technology used to enhance the bioavailability of an active pharmaceutical ingredient in the body of patients. While the physiochemical properties of pegylated monomeric proteins have been extensively described, there is still limited information on the characterization of pegylated oligomeric proteins. In this study, we report the characterization of a pegylated interferon alpha2b (PEGIFN-α2b) concentration-dependent oligomerization by a series of orthogonal biochemical and biophysical methods. These methods include sedimentation velocity and sedimentation equilibrium analytical ultracentrifugation, matrix-assisted laser desorption ionization, and size exclusion chromatography of bissulfosuccinimidyl suberate cross-linked PEGIFN. We report here that PEGIFN-α2b self-associates in a concentration-dependent manner into mainly monomers, dimers, and trimers. In the presence of the chemical cross-linker, PEGIFN-α2b is primarily monomeric (57%) at concentration lower than 0.3 mg/mL and contains about equal amount of monomers and dimers (47.0% and 37.7%, respectively), about 15% of trimers, and up to 4% of higher molecular weight species at 0.7 mg/mL and above.


Assuntos
Antivirais/química , Interferon-alfa/química , Polietilenoglicóis/química , Cromatografia em Gel , Reagentes de Ligações Cruzadas/farmacologia , Eletroforese em Gel de Poliacrilamida , Humanos , Interferon alfa-2 , Proteínas Recombinantes/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Ultracentrifugação
9.
Carbohydr Polym ; 329: 121748, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38286537

RESUMO

Hydrogel beads prepared from protein nanofibers are popular because of their safety, sleek appearance, and protection of biologically active substances. However, extreme external environmental variations, such as pH and temperature, can limit their practical application. To meet the application requirements of hydrogel beads in different environments, non-covalent mixtures of CaCl2 cross-linked soybean protein nanofibers (SNF) and sodium alginate (SA) were used to prepare hydrogel beads. In the present study, the hardness (782.48 g) and elasticity of hydrogel beads formed at SNF/SA = 7:3 and CaCl2 concentration of 0.1 mol/L were the maximum. Furthermore, the water content and pH swelling also reached a peak (98.68 %, 43.85 g/g) due to the best morphology and regular internal network structure. Meanwhile, the pH-responsive hydrogel beads with added anthocyanins were able to respond to the ambient pH under different temperatures and pH conditions and maintained color stability during 96 h of storage (ΔE < 5). In this experiment, a pH-responsive hydrogel bead based on soybean protein nanofiber (SNF) and sodium alginate (SA) was prepared by simple ionic crosslinking. It provides a theoretical and experimental basis for the future application of plant protein nanofibers as pH-responsive hydrogel materials.


Assuntos
Hidrogéis , Nanofibras , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Proteínas de Soja , Alginatos/química , Antocianinas , Cloreto de Cálcio , Concentração de Íons de Hidrogênio
10.
ACS Nano ; 18(16): 10840-10849, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38616401

RESUMO

External electric field has the potential to influence metabolic processes such as biological hydrogen production in microorganisms. Based on this concept, we designed and constructed an electroactive hybrid system for microbial biohydrogen production under an electric field comprised of polydopamine (PDA)-modified Escherichia coli (E. coli) and Ni foam (NF). In this system, electrons generated from NF directly migrate into E. coli cells to promote highly efficient biocatalytic hydrogen production. Compared to that generated in the absence of electric field stimulation, biohydrogen production by the PDA-modified E. coli-based system is significantly enhanced. This investigation has demonstrated the mechanism for electron transfer in a biohybrid system and gives insight into precise basis for the enhancement of hydrogen production by using the multifield coupling technology.


Assuntos
Elétrons , Escherichia coli , Hidrogênio , Polímeros , Escherichia coli/metabolismo , Hidrogênio/metabolismo , Hidrogênio/química , Polímeros/química , Polímeros/metabolismo , Indóis/química , Indóis/metabolismo , Níquel/química , Níquel/metabolismo , Transporte de Elétrons
11.
J Prosthodont ; 22(8): 597-602, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23725052

RESUMO

Various methods of using skeletal anchorage for the intrusion of overerupted maxillary molars have been reported; however, it is difficult to intrude the overerupted upper second molars because of the low bone density in the region of the tuberosity. This article illustrates a new treatment method using partial fixed edgewise appliances and miniscrews to intrude the overerupted upper second molars. The miniscrews were applied to reinforce the anchorage of the upper first molar. The intrusive force was generated by the Ni-Ti wire. The clinical results showed a significant intrusion effect without root resorption or periodontal problems. This report demonstrates that the combination of partial conventional fixed appliances with miniscrews is a simple and effective treatment option to intrude overerupted upper second molars, especially in situations where miniscrews cannot be inserted directly next to the second molar.


Assuntos
Parafusos Ósseos , Procedimentos de Ancoragem Ortodôntica/instrumentação , Técnicas de Movimentação Dentária/instrumentação , Ligas Dentárias/química , Feminino , Humanos , Maxila/patologia , Pessoa de Meia-Idade , Miniaturização , Dente Molar/patologia , Dente Serotino/patologia , Níquel/química , Braquetes Ortodônticos , Fios Ortodônticos , Titânio/química , Erupção Dentária , Técnicas de Movimentação Dentária/métodos , Resultado do Tratamento
12.
ACS Appl Mater Interfaces ; 15(42): 48871-48881, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37816068

RESUMO

Virus-like particle (VLP)-based vaccines are required to be associated with a suitable adjuvant to potentiate their immune responses. Herein, we report a novel, biodegradable, and biocompatible polyphosphoester-based amphiphilic cationic polymer, poly(ethylene glycol)-b-poly(aminoethyl ethylene phosphate) (PEG-PAEEP), as a Hepatitis B surface antigen (HBsAg)-VLP vaccine adjuvant. The polymer adjuvant effectively bound with HBsAg-VLP through electrostatic interactions to form a stable vaccine nanoformulation with a net positive surface charge. The nanoformulations exhibited enhanced cellular uptake by macrophages. HBsAg-VLP/PEG-PAEEP induced a significantly higher HBsAg-specific IgG titer in mice than HBsAg-VLP alone after second immunization, indicative of the antigen-dose sparing advantage of PEG-PAEEP. Furthermore, the nanoformulations exhibited a favorable biocompatibility and in vivo tolerability. This work presents the PEG-PAEEP copolymer as a promising vaccine adjuvant and as a potentially effective alternative to aluminum adjuvants.


Assuntos
Antígenos de Superfície da Hepatite B , Vacinas de Partículas Semelhantes a Vírus , Camundongos , Animais , Polímeros , Adjuvantes de Vacinas , Vacinas contra Hepatite B , Adjuvantes Imunológicos/farmacologia , Adjuvantes Farmacêuticos , Imunidade Celular , Camundongos Endogâmicos BALB C
13.
Int J Nanomedicine ; 18: 7305-7333, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38084124

RESUMO

Spinal cord injury (SCI) treatment represents a major challenge in clinical practice. In recent years, the rapid development of neural tissue engineering technology has provided a new therapeutic approach for spinal cord injury repair. Implanting functionalized electroconductive hydrogels (ECH) in the injury area has been shown to promote axonal regeneration and facilitate the generation of neuronal circuits by reshaping the microenvironment of SCI. ECH not only facilitate intercellular electrical signaling but, when combined with electrical stimulation, enable the transmission of electrical signals to electroactive tissue and activate bioelectric signaling pathways, thereby promoting neural tissue repair. Therefore, the implantation of ECH into damaged tissues can effectively restore physiological functions related to electrical conduction. This article focuses on the dynamic pathophysiological changes in the SCI microenvironment and discusses the mechanisms of electrical stimulation/signal in the process of SCI repair. By examining electrical activity during nerve repair, we provide insights into the mechanisms behind electrical stimulation and signaling during SCI repair. We classify conductive biomaterials, and offer an overview of the current applications and research progress of conductive hydrogels in spinal cord repair and regeneration, aiming to provide a reference for future explorations and developments in spinal cord regeneration strategies.


Assuntos
Traumatismos da Medula Espinal , Regeneração da Medula Espinal , Humanos , Hidrogéis/uso terapêutico , Traumatismos da Medula Espinal/tratamento farmacológico , Materiais Biocompatíveis/uso terapêutico , Engenharia Tecidual , Regeneração Nervosa/fisiologia , Medula Espinal
14.
Colloids Surf B Biointerfaces ; 214: 112454, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35290821

RESUMO

Whole-cell biocatalysis, owing to its high enantioselectivity, environment friendly and mild reaction condition, show a great prospect in chemical, pharmaceutical and fuel industry. However, several problems still limit its wide applications, mainly concerning the low productivity and poor stability. Although the biocatalyst encapsulated in the most-commonly-used alginate hydrogels demonstrate enhanced stability, it still suffers from low biocatalytic productivity, long-term reusability and poor mass diffusion control. In this work, hybrid alginate@polydopamine@SiO2 microcapsules with controlled porosity are designed to encapsulate yeast cells for the asymmetric biosynthesis of (S)- 1-phenylethonal from acetophenone. The hybrid microcapsules are formed by the ionic cross-linking of alginate, the polymerization of dopamine monomers and the protamine-assisted colloidal packing of uniform-sized silica nanoparticles. Alginate provides the encapsulated cells with highly biocompatible environment. Polydopamine enables to stimulate the biocatalytic productivity of the encapsulated yeast cells. Silica shells can not only regulate the mass diffusion in biocatalysis but also enhance the long-term mechanical and chemical stability of the microcapsules. The morphology, structure, chemical composition, stability and molecular accessibility of the hybrid microcapsules are investigated in detail. The viability and asymmetric bioreduction performance of the cells encapsulated in microcapsules are evaluated. The 24 h product yield of the cells encapsulated in the hybrid microcapsules shows 1.75 times higher than that of the cells encapsulated in pure alginate microcapsules. After 6 batches, the 24 h product yield of the cells encapsulated in the hybrid microcapsules is well maintained and 2 times higher than that of the cells encapsulated in pure alginate microcapsules. Therefore, the hybrid microcapsules designed in this study enable to enhance the asymmetric biocatalytic activity, stability and reusability of the encapsulated cells, thus contributing to a significant progress in cell-encapsulating materials to be applied in biocatalytic asymmetric synthesis industry.


Assuntos
Alginatos , Álcool Feniletílico , Alginatos/química , Álcoois Benzílicos , Cápsulas/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Indóis , Polímeros , Porosidade , Saccharomyces cerevisiae , Dióxido de Silício , Estereoisomerismo
15.
World Neurosurg ; 164: e724-e740, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35595047

RESUMO

BACKGROUND: Treatment of Chiari malformation (CM) is controversial, especially when it coexists with "stable" or Type II basilar invagination (CM + II-BI). Precise evaluation of craniovertebral junction (CVJ) stability is crucial in such patients; however, this has never been validated. This study aimed to dynamically evaluate atlanto-condyle and atlantoaxial stability by kinematic computed tomography (CT) and report its surgical treatment. METHODS: The study recruited 101 patients (control, CM, and CM + II-BI groups: 48, 34, and 19 patients, respectively). During kinematic CT, the CVJ stability-related parameters were measured and compared between the 3 groups. The surgical strategy for treating CM + II-BI was based on these results. Preoperative and postoperative images were acquired, and functional scores were used to assess the outcome. RESULTS: Among the 3 groups, the length of the clivus and the height of the condyle were the shortest in the CM + II-BI group, which was accompanied by the greatest rotation of the atlas and atlanto-condyle facet movement on cervical flexion and extension. Moreover, in such patients, increased Chamberlain's baseline violation indicated the aggregate invagination of the odontoid in the flexed position, and asymmetric displacement of atlantoaxial facets was observed. Seventeen CM + II-BI patients underwent surgical treatment with atlantoaxial distraction and occipitocervical fusion. The syringomyelia width and tonsillar herniation decreased significantly, and functional scores indicated symptom relief and good outcomes. CONCLUSIONS: CVJ instability, especially the ultramovement of atlanto-condyle facets, commonly exists in II-BI as evaluated using kinematic CT. The surgical strategy of atlantoaxial distraction and occipitocervical fusion should be considered to treat such patients.


Assuntos
Malformação de Arnold-Chiari , Articulação Atlantoaxial , Platibasia , Fusão Vertebral , Malformação de Arnold-Chiari/complicações , Malformação de Arnold-Chiari/diagnóstico por imagem , Malformação de Arnold-Chiari/cirurgia , Articulação Atlantoaxial/anormalidades , Articulação Atlantoaxial/diagnóstico por imagem , Articulação Atlantoaxial/cirurgia , Fenômenos Biomecânicos , Descompressão Cirúrgica/métodos , Humanos , Platibasia/complicações , Platibasia/diagnóstico por imagem , Platibasia/cirurgia , Fusão Vertebral/métodos , Tomografia Computadorizada por Raios X
16.
Adv Sci (Weinh) ; 9(20): e2201657, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35491498

RESUMO

Molecular light-harvesting capabilities and the production of low-temperature heat output are essential for flexible self-heated textiles. An effective strategy to achieve these characteristics is to introduce photoresponsive molecular interactions (photodynamic bonds) to increase the energy storage capacity and optimize the low-temperature photochromic kinetics. In this study, a series of sulfonic-grafted azobenzene-based polymers interacted with different metal ions (PAzo-M, M = Mg, Ca, Ni, Zn, Cu, and Fe) to optimize the energy level and isomerization kinetics of these polymers is designed and prepared. Photoinduced formation and dissociation of MO dynamic bonds enlarge the energy gap (∆E) between trans and cis isomers for high-energy storage and favor a high rate of isomerization for low-temperature heat release. The suitable binding energy and high ∆E enable PAzo-M to store and release isomerization energy and bond enthalpy even in a low-temperature (-5 °C) environment. PAzo-Mg possesses the highest energy storage density of 408.6 J g-1 (113.5 Wh kg-1 ). A flexible textile coated with PAzo-Mg can provide a high rise in temperature of 7.7-12.5 °C in a low-temperature (-5.0 to 5.0 °C) environment by selectively self-releasing heat indoors and outdoors. The flexible textile provides a new pathway for wearable thermal management devices.


Assuntos
Temperatura Alta , Têxteis , Íons , Isomerismo , Polímeros
17.
Sci China Life Sci ; 65(11): 2269-2286, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35596888

RESUMO

Inducible expression systems are indispensable for precise regulation and in-depth analysis of biological process. Binary Tet-On system has been widely employed to regulate transgenic expression by doxycycline. Previous pig models with tetracycline regulatory elements were generated through random integration. This process often resulted in uncertain expression and unpredictable phenotypes, thus hindering their applications. Here, by precise knock-in of binary Tet-On 3G elements into Rosa26 and Hipp11 locus, respectively, a double knock-in reporter pig model was generated. We characterized excellent properties of this system for controllable transgenic expression both in vitro and in vivo. Two attP sites were arranged to flank the tdTomato to switch reporter gene. Single or multiple gene replacement was efficiently and faithfully achieved in fetal fibroblasts and nuclear transfer embryos. To display the flexible application of this system, we generated a pig strain with Dox-inducing hKRASG12D expression through phiC31 integrase-mediated cassette exchange. After eight months of Dox administration, squamous cell carcinoma developed in the nose, mouth, and scrotum, which indicated this pig strain could serve as an ideal large animal model to study tumorigenesis. Overall, the established pig models with controllable and switchable transgene expression system will provide a facilitating platform for transgenic and biomedical research.


Assuntos
Terapia Genética , Integrases , Masculino , Animais , Suínos , Integrases/genética , Integrases/metabolismo , Transgenes , Animais Geneticamente Modificados , Expressão Gênica
18.
Small ; 7(4): 475-83, 2011 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-21254396

RESUMO

Very uniform and well shaped Mn3O4 nano-octahedra are synthesized using a simple hydrothermal method under the help of polyethylene glycol (PEG200) as a reductant and shape-directing agent. The nano-octahedra formation mechanism is monitored. The shape and crystal orientation of the nanoparticles is reconstructed by scanning electron microscopy and electron tomography, which reveals that the nano-octahedra only selectively expose {101} facets at the external surfaces. The magnetic testing demonstrates that the Mn3O4 nano-octahedra exhibit anomalous magnetic properties: the Mn3O4 nano-octahedra around 150 nm show a similar Curie temperature and blocking temperature to Mn3O4 nanoparticles with 10 nm size because of the vertical axis of [001] plane and the exposed {101} facets. With these Mn3O4 nano-octahedra as a catalyst, the photodecomposition of rhodamine B is evaluated and it is found that the photodecomposition activity of Mn3O4 nano-octahedra is much superior to that of commercial Mn3O4 powders. The anomalous magnetic properties and high superior photodecomposition activity of well shaped Mn3O4 nano-octahedra should be related to the special shape of the nanoparticles and the abundantly exposed {101} facets at the external surfaces. Therefore, the shape preference can largely broaden the application of the Mn3O4 nano-octahedra.


Assuntos
Magnetismo , Compostos de Manganês/química , Nanoestruturas/química , Nanotecnologia/métodos , Óxidos/química , Fotoquímica/métodos , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Nanoestruturas/ultraestrutura , Polietilenoglicóis/química , Rodaminas/química
19.
Arch Toxicol ; 85(11): 1407-17, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21461751

RESUMO

It has been reported that sodium fluoride suppressed proliferation and induced apoptosis in osteoblasts. However, the details about the mechanism at work in bone metabolism are limited. In this study, we further investigated the mechanisms of NaF on proliferation and apoptosis in the primary cultured mouse osteoblasts, which were exposed to different concentration of NaF (10(-6)-5 × 10(-4) M). We examined the effect of NaF on proliferation, cell cycle, apoptosis, oxidative stress, and the protein level of insulin-like growth factor-I (IGF-I) in osteoblasts. All the tested NaF inhibited proliferation and arrested cell cycle at S phase in osteoblasts, and further demonstrated to induce apoptosis in osteoblasts. On the other hand, we found that NaF increased oxidative stress and decreased protein expression of IGF-I. Our study herein suggested that NaF caused proliferation suppression, and apoptosis may contribute to decrease IGF-I expression and increased oxidative stress damage by NaF in the primary mouse osteoblasts.


Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/metabolismo , Osteoblastos/citologia , Estresse Oxidativo/efeitos dos fármacos , Fluoreto de Sódio/farmacologia , Animais , Ciclo Celular/efeitos dos fármacos , Sobrevivência Celular , Células Cultivadas , Flúor/metabolismo , Flúor/toxicidade , Regulação da Expressão Gênica , Fator de Crescimento Insulin-Like I/genética , Camundongos , Camundongos Endogâmicos , Osteoblastos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
20.
Dentomaxillofac Radiol ; 50(6): 20200251, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33444070

RESUMO

OBJECTIVES: The aim of this study was extracting any single tooth from a CBCT scan and performing tooth and pulp cavity segmentation to visualize and to have knowledge of internal anatomy relationships before undertaking endodontic therapy. METHODS: We propose a two-phase deep learning solution for accurate tooth and pulp cavity segmentation. First, the single tooth bounding box is extracted automatically for both single-rooted tooth (ST) and multirooted tooth (MT). It is achieved by using the Region Proposal Network (RPN) with Feature Pyramid Network (FPN) method from the perspective of panorama. Second, U-Net model is iteratively performed for refined tooth and pulp segmentation against two types of tooth ST and MT, respectively. In light of rough data and annotation problems for dental pulp, we design a loss function with a smoothness penalty in the network. Furthermore, the multi-view data enhancement is proposed to solve the small data challenge and morphology structural problems. RESULTS: The experimental results show that the proposed method can obtain an average dice 95.7% for ST, 96.2% for MT and 88.6% for pulp of ST, 87.6% for pulp of MT. CONCLUSIONS: This study proposed a two-phase deep learning solution for fast and accurately extracting any single tooth from a CBCT scan and performing accurate tooth and pulp cavity segmentation. The 3D reconstruction results can completely show the morphology of teeth and pulps, it also provides valuable data for further research and clinical practice.


Assuntos
Tomografia Computadorizada de Feixe Cônico Espiral , Dente , Tomografia Computadorizada de Feixe Cônico , Cavidade Pulpar/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Raiz Dentária
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA